BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a vacuum pump required when installing a separated
unit-type air conditioner wherein an indoor unit and an outdoor unit are connected
by connection pipes, and to a method of . installing an air conditioner using this
vacuum pump.
2. Description of the Related Art
[0002] In a conventional method for installing an air conditioner, in order to exhaust the
air in the indoor device and the air in the connection pipes after installation, refrigerant
gas is previously filled into the main body of the outdoor unit to a volume in excess-of
the specified volume required to display an air conditioning function, for the purpose
of purging the air, this refrigerant gas is introduced into the connection pipes and
indoor unit via a liquid-side two-way valve provided in the. outdoor unit, and thereupon,
the air and refrigerant gas in the connection pipes and inside the indoor unit is
exhausted into the atmosphere by means of a valve known as a gas-side three-way service
port, which is provided in the outdoor unit.
[0003] On the other hand, with increasing restrictions relating to the environment in recent
years, due to the destruction of the ozone layer, global warming, and the like, the
expulsion of refrigerant gas, which has a high ozone layer destruction coefficient
and a high global warming coefficient, into the atmosphere during installation of
air conditioners has become a problem and it is recommended that an electric vacuum
pump is used. By connecting this electric type vacuum pump to a valve known as a gas-side
three-way service port on the outdoor unit, supplying electric power and then activating
the electric vacuum pump, the air in the connection pipes and inside the indoor unit
is sucked out and removed to create a sufficient vacuum state, whereupon the refrigerant
gas is introduced via a liquid-side two-way valve into the connection pipes and indoor
unit.
[0004] However, it becomes relatively difficult to use an electric vacuum pump of this kind
in conditions where the installation position is troublesome, such as on the roof,
or the like. Moreover, using the vacuum pump method, installation takes a long time
compared to a method where refrigerant gas inside the outdoor unit is used.
[0005] Furthermore, the present inventors have also proposed a manual vacuum pump in order
to supplement the electric vacuum pump, but with either a manual or an electric vacuum
pump, the degree of vacuum reached in the connection- pipes and the interior of the
indoor unit is managed by means Of the operating time for which the pump is operated,
along with a Bourdon tube pressure gauge.
[0006] However, a Bourdon tube pressure gauge is very susceptible to shocks, and in many
cases, the zero point is disturbed due to a slight operational mistake by the operator.
Moreover, the smallest graduation on the vacuum gauge is generally large, and rather
than indicating the actual level of vacuum reached, it merely serves as a general
measure for management purposes.
SUMMARY OF THE INVENTION
[0007] The present invention was devised with the foregoing problems of the prior art in
view, an object thereof being to provide a vacuum pump which enables easy installation
of an air conditioner whilst considering the effects on the environment, and an installation
method for an air conditioner using the vacuum pump.
[0008] In order to achieve the aforementioned object, the present invention provides a vacuum
pump, and an installation method for an air conditioner using the vacuum pump, wherein
an intake port with a non-return valve and an exhaust port with a non-return valve
are provided respectively at the top dead center and the bottom dead center of a cylinder
divided into two chambers, an upper chamber and a lower chamber, by means of a position.
When the piston is caused to move in either direction, then if the respective exhaust
ports are coupled together, gas inside the cylinder is exhausted, thereby causing
the exhaust port side to assume a pressurized state, and if the intake ports are coupled,
the intake port side of the cylinder is caused to assume a negative pressure state.
[0009] By means of the present invention, in an installation procedure for an air conditioner,
after coupling an indoor unit to an outdoor unit by means of connection pipes, firstly,
the pump can be used as a pressurizing pump by coupling together the exhaust ports,
and leakage inspection for the pipe connection region can be performed at an applied
atmospheric pressure of up to approximately 5 kg/cm
2. Compared to a conventional leakage inspection method using refrigerant filled into
the outdoor unit, it is possible to achieve a leakage inspection method which is less
harmful to the environment. Thereupon, by coupling the intake ports together and using
the pump as a conventional pressure reducing vacuum pump, it is possible to reduce
the pressure of the air inside the indoor unit and the connection pipes, which must
be exhausted from the viewpoint of the reliability of the refrigerating cycle, to
a suitable level. This series of tasks can be performed manually, without having to
use electrical power.
[0010] Furthermore, the present invention is a vacuum pump wherein the intake ports are
connected together by a connecting portion port section, and when the piston moves
in either direction, the intake port side is caused to assume a negative pressure
state, the vacuum pump being provided with a sensor which is capable of counting the
reciprocal movements of the piston.
[0011] According to the present invention, since the number of reciprocal movements of the
piston can be counted reliably, then if a database is previously prepared to indicate
the capacity of the vacuum pump with respect to the internal volume, based on a.visual
estimate of the length of the piping in the indoor unit and the connection pipes,
then it is possible for the operator readily to estimate the level of vacuum attained,
simply by controlling the number of reciprocal movements of the piston.
[0012] Moreover, the present invention is a vacuum pump and an installation method for an-air
conditioner using same, wherein an intake port provided with a non-return valve and
coupled to the air conditioner, and an exhaust port provided with a non-return valve
and connected to the atmosphere, are installed respectively at the top dead center
of a cylinder which is divided into two chambers, an upper and lower chamber, by a
piston which moves upwards and downwards by means of a handle, and an open port which
is open to the atmosphere and is capable of taking in or exhausting air is provided
at the bottom dead center.
[0013] According to the present invention, after causing the upper chamber to assume a negative
pressure state by moving the piston downwards, the piston is induced to return in
the upward direction, of its own accord, due to an intake action via the open port,
so as to correct the pressure differential between the upper chamber and the lower
chamber, and consequently, virtually no force is required in the upward action of
the piston and hence the piston is easy to operate.
[0014] Furthermore, the embodiments of the present invention are described in detail as
follows.
[0015] In order to achieve the aforementioned object, the vacuum pump according to the present
invention is a vacuum pump, wherein the interior of a cylinder is divided into two
chambers by a piston, intake ports and exhaust ports including non-return valves being
provided respectively at the top dead center and the bottom dead center of the cylinder
divided into two chambers, and when the piston is caused to move in either direction,
then if the respective exhaust ports are coupled together, gas inside the cylinder
is exhaused, thereby causing the exhaust port side of the cylinder to assume a pressurized
state, and if the intake ports are coupled, the intake port side of the cylinder is
caused to assume a negative pressure state. By using this vacuum pump, in an installation
procedure for..an air conditioner, after connecting the indoor unit to the. outdoor
unit by connection pipes, firstly, the pump is used as a pressurizing pump by coupling
the exhaust ports together, and leakage inspection for the pipe connection region
can be performed at an applied atmospheric pressure of up to approximately 5 kg/cm
2. Compared to a conventional leakage inspection method using refrigerant filled into
the outdoor unit, it is possible to achieve a leakage inspection method which is less
harmful to the environment. Thereupon, by coupling the intake ports together and using
the pump as a conventional pressure reducing vacuum pump, it is possible to reduce
the pressure of the air inside the indoor unit and the connection pipes, which must
be exhausted from the viewpoint of the reliability of the refrigerating cycle, to
a suitable level. This series of tasks can be performed manually, without having to
use electrical power.
[0016] Moreover, a compression coil spring is provided inside the non-return valves installed
in the intake ports, the spring constant of the compression coil spring being 0.01
- 0.04 N/mm. Thereby, it is possible to provide a non-return valve having a sufficiently
small minimum operating pressure differential.
[0017] Furthermore, the installation method for an air conditioner according to the present
invention is an installation method for the installation of an air conditioner comprising
an indoor unit and an outdoor unit connected by connection pipes, wherein the vacuum
pump comprises a cylinder, the interior of which is divided into two chambers by a
piston, intake ports and exhaust ports including non-return valves being provided
respectively at the top dead center and the bottom dead center of the cylinder divided
into two chambers, and the installation method comprises, at the least: a first step,
wherein the respective exhaust ports are coupled together and if the piston is caused
to move in either direction, then the gas inside the cylinder is exhausted, thereby
causing the interior of the indoor unit and the connection pipes to assume a pressurized
state; and a second step, wherein the intake ports are coupled together, and the interior
of the indoor unit and the connection pipes are caused to assume a negative pressure
state.
[0018] According to this method, using the exhaust port side of the vacuum pump as a pressurizing
pump, it is possible to perform leakage inspection on the connections at a pressure
of approximately 5 kgf/cm
2, after coupling the indoor unit to the outdoor unit by connection pipes. Compared
to a conventional leakage inspection method using the refrigerant filled into the
outdoor unit, it is possible to achieve a leakage inspection method which is less
harmful to the environment. Moreover, by subsequently using the intake port side as
a pressure reducing vacuum pump, it is possible to set the interior of the indoor
unit and the connection pipes to a sufficient negative pressure state. In this way,
it is possible to install an air conditioner by making effective use of both the exhaust
port side and the intake port side of the vacuum pump.
[0019] Moreover, the method of present invention is an installation method for an air conditioner,
comprising the provision of: a first coupling section for coupling together the exhaust
ports; a second coupling section for coupling together the intake ports; a connecting
section for connecting the first coupling section to the exhaust ports; and a connecting
section for connecting the second coupling section to the intake ports. Moreover,
in the installation method for an air conditioner, the connecting sections are detachable.
Thereby, by providing readily detachable connecting sections on the intake ports and
exhaust ports, in the installation of an air conditioner, firstly, the exhaust port
side can be used as a pressurizing pump for performing-leakage inspection of the connection
section, and then the exhaust port side can be used as a conventional pressure reducing
vacuum pump. By providing readily attachable and detachable connecting sections in
this way, it is possible to divide the mechanical function of the vacuum pump according
to the present invention between a pressurizing device and a pressure reducing device.
[0020] Furthermore, the present invention is a vacuum pump, wherein the interior of a cylinder
is divided into two chambers by a piston, the vacuum pump comprises intake ports and
exhaust ports including non-return valves being provided respectively at the top dead
center and the bottom dead center of the cylinder divided into two chambers, the respective
intake ports are coupled together by means of a coupling port section, the pressure
differential between the two chambers is gradually reduced from an initial presuure
differential, as the intake port side is caused to assume a negative pressure state,
by movement of the piston in either direction, and a sensor is provided for counting
the number of reciprocal movements of the piston. By this means, when installing an
air conditioner, it is possible, for example, to reduce the pressure inside the connection
pipes and the indoor unit, thereby drawing in refrigerant gas from the outdoor unit,
via the service port of the gas-side three-way valve in the outdoor unit. Moreover,
since the sensor counts the reciprocal movements of the piston, the level of vacuum
attained on the intake port side can be estimated. For example, if a database is previously
prepared to indicate the capacity of the vacuum pump with respect to the internal
volume, based on a visual estimate of the length of the piping in the indoor unit
and the connection pipes, then it is possible for the operator readily to estimate
the level of vacuum-attained, by controlling the number of reciprocal movements of
the piston. Furthermore, there is no requirement for special caution in handling the
vacuum pump, and the piston can be operated manually.
[0021] Moreover, in the vacuum pump of the present invention, the sensor is an acceleration
sensor and the response sensitivity thereof is 1 to 5 G. Since an acceleration sensor
having a response sensitivity of 1 to 5 G is used as the sensor for counting the reciprocal
movements of the piston, then it is possible to count only the accelerations G caused
when the piston impacts with the inner wall of the cylinder. Thereby, by using an
acceleration sensor capable of responding to an acceleration of 1 to 5 G, it is possible
to count accurately only the accelerations G caused when the piston impacts with the
inner wall of the cylinder, thus providing a sensor which does not provide an inaccurate
count, such as double counting or missed counting of the stroke movements of the piston.
[0022] Furthermore, in the vacuum pump, the sensor has a construction using a wire spring
or an arm held by a cantilever, and the wire spring or arm can be made to respond
accurately to the accelerations G having a uniform direction caused by reciprocal
movements of the piston. In this way, since the acceleration G is received by means
of a wire spring or a cantilevered arm, it is possible to provide an acceleration
sensor which is able to respond accurately to accelerations G having a uniform direction,
such as the reciprocal movements. in the stroke action of the piston.
[0023] Furthermore, the acceleration sensor is a mechanical sensor, the mechanism thereof
being a pressure contact system, a reed switch system or a conductive contact system,
and by adopting a mechanical sensor based on a pressure contact system, a reed switch
system or a conductive contact system, it is possible to achieve a relatively simple
structure. In this way, by a adopting a mechanical system and using a pressure contact
system, a reed switch system or a conductive contact system for the mechanism thereof,
it is possible to count the acceleration G accurately, by means of a relatively simple
mechanical structure, for example, a wire spring, a pendulum or electrical contacts.
[0024] Moreover, in order to achieve the aforementioned object, the present invention is
a vacuum pump, wherein the interior of a cylinder is divided into an upper chamber
and a lower chamber by a piston, the piston being coupled to a handle which causes
the piston to move by means of a supporting shaft provided on the upper chamber side
thereof, an intake port including a non-return valve and an exhaust port including
a non-return valve each being provided at the top dead center of the upper chamber,
an open port provided in the lower chamber of the cylinder and being capable of taking
in or exhausting air, the upper chamber being caused to assume a negative pressure
state by movement of the piston in the downward direction, and furthermore, the piston
being moved in the upward direction by the intake action via the open port. For example,
when installing an air conditioner, if the indoor unit is connected to the outdoor
unit by connection pipes and the intake port and exhaust port are used as a pressure
vacuum pump, then when the upper chamber has been caused to assume a negative pressure
state by moving the piston downwards, the piston will then be induced to return in
an upward direction, of its own accord, due to an intake action via the open port,
so as to correct the pressure differential between the upper chamber and the lower
chamber. Consequently, whilst a uniform force is required to move the piston in a
downward direction, virtually no force is required to move it in the upward direction,
and hence a light operation is achieved. For example, it is possible to reduce the
pressure of the oxygen in the air, which must be exhausted from the viewpoint of the
reliability of the refrigerating cycle, to a suitable level, in addition to which,
the operation of the piston can be performed manually, without having to use electrical
power, which is a great merit.
[0025] Furthermore, the present invention is an installation method for an air conditioner
when using a vacuum pump to install an air conditioner comprising an indoor unit and
an outdoor unit connected by connection pipes, wherein the vacuum pump comprises a
cylinder, the interior of which is divided into an upper chamber and a lower cylinder
by a piston, the piston being coupled to a handle which causes the piston to move
by means of a supporting shaft provided on the upper chamber side thereof, an intake
port and an exhaust port including non-return valves and provided at the top dead
center of the upper chamber, and an open port provided in the lower chamber of the
cylinder and being capable of taking in or exhausting air; the relationship between
A, which is the total volume of the internal spatial volume of the upper chamber formed
when the piston is at the bottom dead center and the internal volume of the space
from the cylinder outlet to the intake port non-return valve and the exhaust port
non-return valve, and B, which is the total volume of the cylinder internal dead space
formed when the piston is at the top dead center, and the internal volume of the space
from the cylinder outlet to the intake port non-return valve and the exhaust port
non-return valve; is V1a/V1b ≥ 20; and after the upper chamber has been caused to
assume a negative pressure state by moving the piston in a downward direction, the
piston is induced to move in the upward direction by the intake action via the open
port, whilst the interior of the indoor unit and the connection pipes is caused to
assume a negative pressure state.
[0026] Furthermore, the present invention is an installation method for an air conditioner
when using a vacuum pump to install an air conditioner comprising an indoor unit and
an outdoor unit connected by connection pipes, wherein the vacuum pump comprises a
cylinder, the interior of which is divided into an upper chamber and a lower cylinder
by a piston, the piston being coupled to a handle which causes the piston to move
by means of a supporting shaft provided on the upper chamber side thereof, an intake
port and an exhaust port including non-return valves and provided at the top dead
center of the upper chamber, and an open port provided in the lower chamber of the
cylinder and being capable of taking in or exhausting air; the relationship between
A, which is the total volume of the internal spatial volume of the upper chamber formed
when the piston is at the bottom dead center and the internal volume of the space
from the cylinder outlet to the intake port non-return valve and the exhaust port
non-return valve, and B, which is the total volume of the cylinder internal dead space
formed when the piston is at the top dead center, and the internal volume of the space
from the cylinder outlet to the intake port non-return valve and the exhaust port
non-return valve, is V1a/V1b ≥ 20, and more desirably, V1a/V1b ≥ 40; and after the
upper chamber has been caused to assume a negative pressure state by moving the piston
in a downward direction, the piston is induced to move in the upward direction by
the intake action via the open port, whilst the interior of the indoor unit and the
connection pipes is caused to assume a negative pressure state. Therefore, in the
installation procedure for the air conditioner, it is possible to reduce the oxygen
in the air, which must be eliminated from the viewpoint of the reliability of the
refrigerating cycle, to a suitable level, and hence the installation of the air conditioner
can be completed in a short period of time.
[0027] Furthermore, the present invention is an installation method for an air conditioner
wherein, in the installation process, the interior of the indoor unit and the connection
pipes are caused to assume a negative pressure state, after a specific gas has been
introduced into the indoor unit and the connection pipes and the air inside the indoor
unit and the connection pipes has been substituted by the specific gas. By means of
this method, since the vacuum pump is used after the air in the indoor unit and the
connection pipes has been substituted with a gas which will not be detrimental to
the refrigerating cycle, even if it is left during the installation process, such
as carbon dioxide gas, then it is possible to a reliable installation process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028]
Fig. 1 is a block diagram of an air conditioner according to the present invention;
Fig. 2 is a diagram showing a construction of a vacuum pump main body and a pressure-resistant
hose connection path according to the present invention;
Fig. 3 is an enlarged diagram of an essential part á of the vacuum pump shown in Fig.
2;
Fig. 4 is a schematic diagram of an acceleration sensor provided in a handle of the
vacuum pump according to the present invention;
Fig. 5 is a schematic diagram of a non-return valve provided in an air exhaust port
according to the present invention;
Fig. 6 is a sectional view along a face A - A' in the non-return valve in Fig. 5;
Fig. 7 is a schematic diagram of a non-return valve provided in an air intake port
according to the present invention;
Fig. 8 is an enlarged diagram of the principal section β of the vacuum-pump shown
in Fig. 2;
Fig. 9 is a schematic diagram of a filter section according to the present invention;
Fig. 10 is a concrete view showing a dead space when the piston is at the bottom dead
center, in the principal section γ of the vacuum pump shown in Fig. 2;
Fig. 11 graph of the relationship between the number of strokes and the internal pressure
in a vacuum pump according to the present invention;
Fig. 12 is a diagram showing the construction of the main body of a vacuum pump according
to the present invention, and the connection path of the pressure-resistant hoses
connected to the exhaust port side;
Fig. 13 is a diagram showing the construction of the main body of a vacuum pump according
to the present invention, and the connection path of the pressure-resistant hoses
connected to the intake port side;
Fig. 14 is a graph of the relationship between the number of strokes and the internal
pressure in a vacuum pump according to the present invention;
Fig. 15 is a diagram showing the construction of the main body of a vacuum pump according
to the present invention, and the connection path of the pressure-resistant hoses
connected to the exhaust port side;
Fig. 16 is a diagram showing the construction of the main body of a vacuum pump according
to the present invention, and the connection path of the pressure-resistant hoses
connected to the intake port side;
Fig. 17 is a schematic diagram showing the air flow on the intake port side of the
filter section according to the present invention;
Fig. 18 is a schematic diagram showing the air flow on the exhaust port side of the
filter section according to the present invention;
Fig. 19 is a schematic diagram of a one-touch pipe joint provided on the main body
of the vacuum pump according to the present invention;
Fig. 20 is a concrete view showing a dead space when. the piston is at the bottom
dead center, in the principal section δ of the vacuum pump shown in Fig. 14;
Fig. 21 is a graph of the relationship between the number of strokes and the internal
pressure of a vacuum pump according to the present invention;
Fig. 22 is a flowchart of the procedure until an acceleration sensor of the vacuum
pump according to the present invention displays a count;
Fig. 23 is a schematic schematic diagram showing an acceleration sensor installed
on the handle of a vacuum pump according to the present invention;
Fig. 24 is a schematic diagram showing a strain gauge of an acceleration sensor of
a vacuum pump according to the present invention;
Fig. 25 is a detection circuit diagram of a strain gauge of an acceleration sensor
in a vacuum pump according to the present invention;
Fig. 26 is a graph of the relationship between the number of strokes and the internal
pressure of a vacuum pump according to the present invention;
Fig. 27 is a schematic diagram showing a counter built into an acceleration sensor
provided in the handle of a vacuum pump according to the present invention;
Fig. 28 is a schematic diagram showing the mechanism of an acceleration sensor in
a vacuum pump according to the present invention;
Fig. 29 is a schematic diagram showing a counter built into an acceleration sensor
provided in the handle of a vacuum pump according to the present invention;
Fig. 30 is a schematic diagram showing the mechanism of an acceleration sensor in
a vacuum pump according to the present invention;
Fig. 31 is a schematic diagram showing a counter built into an acceleration sensor
provided in the handle of a vacuum pump according to the present invention;
Fig. 32 is a schematic diagram showing the mechanism of an acceleration sensor in
a vacuum pump according to the present invention;
Fig. 33 is a refrigerant cycle diagram showing an air conditioner installed using
the vacuum pump of the present invention;
Fig. 34 is a diagram showing the construction of a vacuum pump according to the present
invention and the connection path of a pressure-resistant hose;
Fig. 35 is a detailed schematic diagram of a case where the piston shown in Fig. 2
of the vacuum pump according to the present invention is situated at the top dead
center; and
Fig. 36 is a diagram showing the construction of the vacuum pump according to the
present invention and the connection path of a pressure-resistant hose.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Below, embodiments of the present invention are described with reference to the drawings.
(First embodiment)
[0030] Fig. 1 is a schematic diagram of a refrigeration cycle of an air conditioner described
in the embodiment. The refrigeration cycle comprises, as typical components: a compressor
1, a four-way valve 2, an outdoor, heat exchanger 3, an aperture device 4, a drier
5, and an indoor heat exchanger 6. The compressor 1, four-way valve 2, outdoor heat
exchanger 3, aperture device 4, and drier 5 are situated in an outdoor unit A, and
the indoor heat exchanger 6 is situated in an indoor unit B.
[0031] A liquid side two-way valve 7 and a gas-side three-way valve 8 are provided in the
outdoor unit A. Connection pipes 9, 10 for connecting the outdoor unit A and the indoor
unit B are respectively connected via the liquid-side two-way valve 7 and the gas-side
three-way valve 8. The liquid-side two-way valve has a screw section 7a, and by opening
this screw section 7a, the pipe of the outdoor unit A and the connection pipe 9 are
coupled. Moreover, the gas-side three-way valve 8 has a screw section 8a and a service
port section 8b, and by opening the screw section 8a, the pipe of the outdoor unit
A and the connection pipe 10 are coupled together.
[0032] The outdoor unit A and indoor unit B are connected by indoor/outdoor connection pipes
9, 10, a central port 12a of a gauge manifold 12 being coupled via a pressure-resistant
hose 11 to the service port section 8b of the gas-side three-way valve 8 on the outdoor
unit A, and a low-pressure side port 12b of a gauge manifold 12 being coupled to a
pressure-resistant hose 13 forming a coupling section which couples the two suction
ports into a single port. A filter section 14 is provided in the path of the hose
13.
[0033] Fig. 2 shows a schematic diagram for giving a detailed description of the construction
of the vacuum pump main unit and the connection paths of the pressure-resistant hoses.
[0034] The structure of the vacuum pump comprises an aluminium piston 16 disposed inside
an aluminium cylinder main body 15 in such a manner that it divides the interior of
the cylinder into two chambers, the piston 16 being coupled via a stainless steel
supporting shaft 17 to an aluminium handle 18. An acceleration sensor 181 and a primary
electric cell 182 are built into the handle 18, and a display 183 is provided on the
surface of the upper portion of the handle 18, in such a manner that a signal from
the acceleration sensor 181 can be displayed on the display 183.
[0035] Fig. 3 shows a schematic diagram of the construction of a handle 18, and Fig. 4 shows
a schematic diagram of an acceleration sensor 181.
[0036] The acceleration sensor 181 comprises a thinly formed sensor section consisting of
a semiconductor and a weight section having a large surface area. In operation, when
the stroke movement of the handle 18 halts and an acceleration of G is generated,
the weight section receives this and the sensor section distorts. Due to this distortion,
the electrical resistance of the diffused layer formed on the upper part of the sensor
section changes. The stress caused by the distortion of the sensor section due to
this acceleration is detected by a piezo effect of the sensor section, and is converted
to a voltage output by means of a bridge circuit. The total weight of the vacuum pump
main body is approximately 1 kg.
[0037] A construction is adopted wherein non-return valves 19a, 19b, 20a, 20b connect directly
to the main wall of the cylinder in the regions where the piston 16 forms a top dead
center face and a bottom dead center face when it moves inside the cylinder 15. In
this case, a structure as illustrated in Fig. 5 and Fig. 6 is used for the exhaust
port non-return valves 19a, 19b, and a structure as illustrated in Fig. 7 is used
for the intake port non-return valves 20a, 20b. The copper tube 191 of the exhaust
port non-return valves 19a, 19b is processed with roll grooves at two points, and
a brass valve seating member 192 is fixed in groove section 191a. A nylon valve member
193 impacts with the valve seating member 192, and the movement thereof is halted
by a contact face with the valve seating member 192 in a section having an oblique
face. Moreover, in the opposite direction, the movement of the valve member is halted
by the groove section 191b. Therefore, a non-return valve structure is obtained wherein
air only flows in the direction of the arrow. The copper tube 201 of the intake non-return
valves 20a, 20b is processed with roll grooves at two points, and a brass valve seating
member 202 is fixed to the groove section 201a. A compression coil spring member 203
is connected to a film plate 204 and under the force of the compression coil spring,
the nylon film plate 204 is caused to impact with a brass valve seating member 205,
the fluid path being sealed by the contact between the respective faces of the seating
member 205 and the film plate 202, thereby achieving a non-return valve structure
wherein air is only able to flow in the direction of the arrow. Using a spring made
from SUS 304 steel with a spring constant of 0.04 N/mm for the compression coil spring
member 203, it was possible to achieve a minimum operating pressure differential of
10 torr. A brass valve seating member 205 is fixed by the groove section 201b, and
it is provided with a tapered section, with the object of slightly increasing the
pressure differential required to operate the valve by reducing the suction flow path
surface area in the flow path on the upstream side of the valve seating member 205.
[0038] Furthermore, shaft seals 21a, 21b are disposed in the region where the supporting
shaft 17 meets the outer wall of the cylinder 15, as illustrated in Fig. 8, the seals
being constituted by a dual O-rings made from HNBR. A shaft seal 22 consisting of
an O-ring made from HNBR is also provided in the portion of the piston 16 where it
contacts the inner wall of the cylinder 15.
[0039] Fig. 9 shows the internal construction of the filter section 14. The main body of
the filter section 14 has a circular tubular shape, and air entering into the filter
soon confronts a wall 141 and is caused to change direction to flow in an outward
radial direction, then passing through a tubular pulp film 142 disposed in a fixed
position inside the filter body, and being introduced into an internal passage, before
finally being directed out of the filter. Consequently, when the air passes from the
outer passage to the inner passage, dirt is trapped. Moreover, if the cylindrical
tube 143 of the filter section 14 is made from a transparent glass or resin, then
the state of the trapped dirt can be observed visually.
[0040] Next, the operation of the vacuum pump will be described. Firstly, when the handle
18 is pulled in direction a (towards the top dead center), the air inside the indoor
unit B and the connection pipe 9 is drawn in from the service port section 8b and
via the pressure-resistant hose 11, the gauge manifold 12, and the pressure-resistant
hose 13, and into the cylinder interior section 14b via the non-return valve 20b at
the intake port, whilst conversely, the air in the cylinder interior section 14a is
exhausted into the atmosphere via the non-return valve 19a at the exhaust port. Thereupon,
when the handle 18 is pushed in direction b (towards the bottom dead center), the
air in the indoor unit B and the connection pipe 9 is drawn in from the service port
section 8b and via the pressure-resistant hose 11, the gauge manifold 12, and the
pressure-resistant hose 13, and into the cylinder interior section 14a via the non-return
valve 20a at the intake port, whilst conversely, the air in the cylinder interior
section 14b is exhausted into the atmosphere via the non-return valve 19b at the exhaust
port. Thereupon, when reciprocal movement of the handle 18 is performed, whereby the
handle 18 is again pulled in direction a (towards the top dead center), then the piston
16 performs synchronized movement. In this case, the interior of the cylinder constantly
reduces in pressure, whether the piston moves in direction a or direction b, whilst
the four non-return valves are switched alternately, and ultimately, a sufficient
negative pressure state can be achieved. In strict terms, it is possible to continue
the pressure reducing mechanism, as long as it is possible to generate a pressure
differential between the interior of the pressure-resistant hose 13 and the interior
of the cylinder 14a or 14b when performing reciprocal movement of the handle 18. Therefore,
the non-return valves 20a and 20b provided at the intake ports are required to have
a low minimum operating pressure differential. In the case of a non-return valve as
in the present embodiment, the factor determining this minimum operating pressure
differential is the spring constant of the compression coil spring member 203.
[0041] The series of reciprocal movements is detected by the acceleration sensor 181 and
the number of stroke operations of the handle 18 can be displayed on the display 183.
In the initial period of using the vacuum pump, a large pressure differential is created
between the cylinder interior sections 14a and 14b, but by reciprocal movement of
the piston, this differential pressure state is gradually attenuated. In this case,
the shaft seals 21a and 21b ensure a sufficient differential pressure state between
the negative pressure (30 torr or less) inside the cylinder 14, and the external air
(760 torr), and in order to prevent any leakage of air, a dual O-ring structure is
used for the seals. By adopting a dual-ring structure, it is possible to prevent foreign
material, which is liable to adhere to and infiltrate inside the seal section when
the supporting shaft is operated. Furthermore, the shaft seal 22 provides a sufficient
guarantee of a differential pressure state created when the piston 16 is made to perform
reciprocal movement, by means of a single O-ring.
[0042] A specific installation procedure is now described. The pressure-resistant hose 13
of the vacuum pump is connected to the low pressure port 12b of the gauge manifold
12, and then attached to the service port section 8b, thereby achieving a state where
the interior of the pressure-resistant hose 11 is connected with the indoor unit B
and the connection pipe 9. Moreover, the interior of the pressure-resistant hose 13
is connected by opening the low pressure side handle 12c of the gauge manifold 12.
Thereupon, reciprocal movement of the handle 18 of the vacuum pump is performed, and
by reading off the number of stroke operations thereof, from the display 183, the
operator is able to estimate when the interior of the indoor unit B and the connection
pipe 9 has reached a sufficient state of negative pressure. Furthermore, the sufficient
negative pressure state is ultimately judged by the operator from the scale of the
vacuum gauge 12d of the gauge manifold 12. Immediately, the low pressure side handle
12c of the gauge manifold 12 is closed, and after waiting for a short while, it is
confirmed that there is no change in the reading of the vacuum gauge 12d. Here, if
there is a change in the reading, then there is a point at which an air leak is occurring
in the connection pipe section. Next, the screw section 7a of the liquid side two-way
valve 7 is slightly loosened and refrigerant gas from the outdoor unit A is introduced,
whereby the connection pipes 9, 10 and the interior of the pipes in the indoor unit
B assume a slightly positive pressure state (approximately 0.2 kgf/cm
2). Thereupon, the pressure-resistant hose 11 is detached from the service port section
8b, the screw section 7a of the liquid-side two-way valve 7 is rotated by a further
1/4 turn, and the state of leakage of the connection pipe section is rechecked at
an applied pressure of (3 - 6 kgf/cm
2). Finally, the screw section 7a of the liquid-side two-way valve 7 is opened fully,
and the screw section 8a of the gas-side three-way valve 8 is opened fully, thereby
completing the installation tasks relating to the installation of an air conditioner.
[0043] In the present embodiment, the internal volume of the piping of the indoor unit B
including the indoor heat exchanger 6, and the connection pipes 9, 10, was 1.5 litres.
In the vacuum pump, the internal volume of the cylinder space when the piston is at
the top dead center was 150 ml (27 dia × 260 mm), and the total volume from the cylinder
outlet formed when the piston is at the bottom dead center, to the intake port and
exhaust port non-return valves; was 1.5 ml. These figures are taken to include the
port flow path space arising in the cylinder wall. The cylinder internal dead space
formed when the piston is at the bottom dead center was 2 ml. Taking Via to be the
total volume of the internal volume of the cylinder space when the piston is at the
top dead center, the cylinder internal dead space formed when the piston is at the
bottom dead center, and the volume of the internal space from the cylinder outlet
to the non-return valves of the intake ports and exhaust ports, and taking V1b to
be the total volume of the cylinder internal dead space formed when the piston is
at the bottom dead center, and the volume of the internal space from the cylinder
outlet to the non-return valves of the intake ports and exhaust ports, the relationship
between V1a and V1b is V1a/V1b.
[0044] Fig. 10 shows a concrete illustration of the V1b portion comprising the cylinder
internal dead space and the total volume of the internal space from the cylinder outlet
when the piston is at the bottom dead center to the intake port and exhaust port non-return
valves. By adopting a structure wherein an intake port and exhaust port are embedded
in the cylinder wall at positions corresponding to the top dead center face and the
bottom dead center face of the cylinder main body, in such a manner that each pair
of non-return valves are directly connected, a system structure design is achieved
wherein the portion forming the dead space in the pressure-reducing mechanism is a
minimum.
[0045] In this case, by following the aforementioned work procedure, it was possible to
achieve 30 torr using the vacuum pump, by performing 40 strokes of reciprocal movement
of the handle. Fig. 11 shows the progress of the state of pressure reduction, in the
form of the relationship between the number of strokes and the internal pressure.
The progress of pressure reduction was confirmed up to 50 strokes, but the vacuum
level attained reached a state of equilibrium at 40 strokes and did not advance further
thereafter. Consequently, it can be seen that when a vacuum pump according to the
present embodiment is applied to a system having an internal volume of 1.5 litres,
then 40 strokes is the general standard for the attained vacuum level. To obtain an
accurate figure, the vacuum level was monitored separately using a digital pressure
sensor.
(Second embodiment)
[0046] Fig. 12 is a schematic diagram giving a detailed illustration of a pressure-resistant
hose connection path connecting the vacuum pump main mechanism with the exhaust port
according to the present embodiment, and Fig. 13 is a schematic diagram of a pressure-resistant
hose connection path connecting to the intake port side. In the present embodiment,
a vacuum pump main body similar to the first embodiment is used, but a pressure-resistant
hose 23 is provided which forms a coupling section for coupling the exhaust ports
into one. The constitutional elements which are similar to the first embodiment are
not described in detail here.
[0047] Next, the effects of the present embodiment are described in terms of the operational
mechanism of the vacuum pump. Firstly, when the handle 18 is pulled in direction a
(towards the top dead center), the air in the cylinder interior section 14a is drawn
via the non-return valve 19a forming an exhaust port into the indoor unit B and connection
pipe 9. Thereupon, when the handle 18 is pushed in direction b (towards the bottom
dead center), the air in the cylinder interior section 14b is drawn via the non-return
valve 19b forming an exhaust port into the indoor unit B and the connection pipe 9.
Thereupon, the handle 18 is caused to perform reciprocal movement, in such a manner
that the handle 18 is pulled again in direction a (towards the top dead center), and
the piston 16 becomes synchronized. In this case, the interior of the cylinder can
be used as a pressurizing pump, which constantly causes the indoor unit B and the
interior of the connection pipe 9 to be in a pressurized state due to the atmosphere,
whether the piston moves in direction a or direction b, whilst the four non-return
valves are switched alternately. Since this operation is performed manually, there
is a natural limit on the pressurization level, and anyone can readily achieve a level
of approximate 5 kg/cm
2.
[0048] Now, a concrete installation procedure is described. An indoor unit B and outdoor
unit A are connected by connection pipes, the exhaust port side pressure-resistant
hose 23 of the vacuum pump is connected to the low pressure port 12b of the gauge
manifold 12, and this is then attached to the service port section 8b, whereby the
interior of the pressure-resistant hose 11 becomes connected to the interior of the
indoor unit B and the connection pipe 9. Furthermore, the interior of the pressure-resistant
hose 13 is connected by opening the low pressure side handle 12c of the gauge manifold
12. Thereupon, the handle 18 of the vacuum pump is caused to perform reciprocal movement,
and when the pump has become difficult for the operator to work using his or her own
strength, the low pressure side handle 12c is closed, thereby setting the interior
of the indoor unit B and the connection pipe 9 to a pressurized state at an atmosphere
of approximately 5 kg/cm
2. By waiting for a short while whilst confirming the pressure level using a vacuum
gauge 12d, it is possible to check for leaks relating to the connection pipe sections.
Thereupon, the pressure-resistant hose 23 is detached from the lower pressure side
port 12b of the gauge manifold 12 and the low pressure side handle 12c is opened,
thereby allowing the pressurized air to escape externally, and returning the interior
to a normal pressure state. Next, the pressure-resistant hose 13 of the vacuum pump
is connected to the low pressure port 12b of the gauge manifold 12. Here, the low
pressure side handle 12c of the gauge manifold 12 is open, and hence the indoor unit
B and the connection pipe 9 are in a connected state. When the handle 18 of the vacuum
pump is caused to perform reciprocal movement, the pressure can gradually be reduced,
and by reading the number of strokes of reciprocal movement from the display 183,
the operator is able to estimate when the interior of the indoor unit B and the connection
pipe 9 has reached a sufficient negative pressure state. Furthermore, the sufficient
negative pressure state is ultimately judged by the operator from the scale of the
vacuum gauge 12d of the gauge manifold 12. Immediately, the low pressure side handle
12c of the gauge manifold 12 is closed. Next, the screw section 7a of the liquid side
two-way valve 7 is loosened and refrigerant gas from the outdoor unit A is introduced,
whereby the connection pipes 9, 10 and the interior of the pipes in the indoor unit
B assume a slightly positive pressure state (approximately 0.2 kgf/cm
2). Thereupon, the pressure-resistant hose 11 is detached-from the service port section
8b, and the screw section 7a of the liquid-side two-way valve 7 is opened fully, and
the screw section 8a of the gas-side three-way valve 8 is opened fully, thereby completing
the installation tasks relating to the installation of an air conditioner.
[0049] In the present embodiment, the internal volume of the indoor unit B piping including
the indoor heat exchanger 6, and the connection pipes 9, 10, was 1.5 litres. In the
vacuum pump, the internal volume of the cylinder space when the piston is at the top
dead center was 250 ml (27 dia. × 440 mm), and the total internal volume from the
cylinder outlet formed when the piston is at the bottom dead center, to the intake
port and exhaust port non-return valves, was 1.5 ml. These figures are taken to include
the port flow path space arising in the cylinder wall. The cylinder internal dead
space formed when the piston is at the bottom dead center was 2 ml. The relationship
between V1a and V1b determined in a similar manner to the first embodiment is V1a/V1b
= 72.
[0050] Here, using the vacuum pump in accordance with the work procedure described above,
it was possible to achieve 18 torr by performing 40 strokes of reciprocal movement
of the handle. Fig. 14 shows the progress of the state of pressure reduction, in the
form of the relationship between the number of strokes and the internal pressure.
After 25 strokes, the pressure was 30 torr or less, and the progress of pressure reduction
was confirmed up to 50 strokes, but the vacuum level attained reached a state of equilibrium
at 40 strokes and did not advance further thereafter. Consequently, it can be seen
that when a vacuum pump according to the present embodiment is applied to a system
having an internal volume of 1.5 litres, then 40 strokes is the general standard for
the attained vacuum level. To obtain an accurate figure, the vacuum level was monitored
separately using a digital pressure sensor.
[0051] In the present embodiment, by using the exhaust port side of a vacuum pump as a pressurizing
pump, it was possible to perform adequate leak inspection associated with the installation
work. In the prior art, the only method available was to use the refrigerant in the
leak inspection of the connection pipes and indoor unit, but here, it is possible
to provide an installation method for an air conditioner which is not harmful to the
environment, by using pressurized air to perform a leak inspection.
(Third embodiment)
[0052] In this embodiment, no gauge manifold 12 is interposed in the path from the service
port to the vacuum pump. Fig. 15 shows a schematic diagram which gives a detailed
illustration of a pressure-resistant hose connection path connecting a vacuum pump
main body and an exhaust port side according to the present embodiment, and Fig. 16
is a schematic diagram of a pressure-resistant hose connection path connected to the
intake port side. The structure of the vacuum pump comprises an aluminium piston 27
which is disposed inside an aluminium cylinder main body 15 in such a manner that
it divides the interior of the cylinder into two chambers, the piston 27 being coupled
via a stainless steel supporting shaft 17 to an aluminium handle 18. An acceleration
sensor is built into the handle 18, similarly to the first embodiment, in such a manner
that signals from the acceleration sensor are displayed on a display. In the present
embodiment, a construction is adopted wherein non-return valves 30a, 30b, 31a, 31b
connect directly to the main wall of the cylinder in the regions where the piston
27 forms a top dead center face and a bottom dead center face when it moves inside
the cylinder 15. The non-return valves 30a, 30b used for the exhaust ports and the
non-return valves 31a, 31b used for the intake ports are similar to those used in
the first embodiment. Moreover, shaft seals similar to those of the first embodiment
are provided in the region where the supporting shaft 17 meets the cylinder wall,
and a shaft seal 22 is also provided on the portion of the piston 27 which contacts
the inner wall of the cylinder 15.
[0053] Figs. 17 and 18 illustrate the internal construction of a filter section 14 and the
flow of air therein. The main body of the filter section 14 has a circular tubular
shape, and when the filter section 14 is used on the intake port side, in other words,
as illustrated in Fig. 17, then air entering into the filter immediately confronts
a wall 25 and is caused to change direction to flow towards an outer flow path 252,
and it then passes through a tubular pulp film 253 provided in a fixed position inside
the filter and into an inner passage 254, before finally being directed out of the
filter. Furthermore, if used on the exhaust port side, in other words, as illustrated
in Fig. 18, then air exiting from the internal passage 254 to the outer side of the
tubular pulp film 253 confronts a tubular pulp fibreless cloth 255 provided on the
inner wall of the tubular main body of the filter section 14, and is exhausted out
of the filter via the outer passage 252. Consequently, a construction is achieved
wherein, when the filter is used on the intake port side, dirt is trapped by the tubular
pulp film 253 which has a relatively small mesh size, whereas when the filter is used
on the exhaust port side, dirt is trapped by a tubular fibreless cloth 255 having
a relatively large mesh size.
[0054] The exhaust port non-return valves 30a, 30b used have a similar structure to that
in the first embodiment illustrated in Fig. 5 and Fig. 6, and the intake port non-return
valves 31a, 31b used have a similar structure to that in the first embodiment illustrated
in Fig. 7.
[0055] One-touch pipe joints 34a, 34b are provided respectively at the exhaust port non-return
valves 30a, 30b, via joint sections 33a, 33b. Furthermore, one-touch pipe joints 36a,
36b are provided respectively at the intake port non-return valves 31a, 31b, via joint
sections 35a, 35b. The structure of the one-touch pipe joints 34a, 34b, 36a, 36b is
virtually the same, and Fig. 19 illustrates schematically the construction taking
the one-touch pipe joint 34a as a typical example. The concrete construction is described
below. A release bush 341 is provided around the pressure-resistant hose, and the
release bush 341 is fixed by providing a guide 343 and collet 344 on the main body
342. A chuck 345 is disposed between the release bush 341 and collet 344, and the
chuck 345 is caused to fit into the pressure-resistant hose, thereby preventing detachment
of the pressure-resistant hose, by pushing the chuck 345 in the direction of the pressure-resistant
hose by means of a CR rubber lip seal 346. Furthermore, since the pressure of of the
chuck 345 can be released by pushing the release bush 341 towards the inner side along
the pressure-resistant hose, the pressure-resistant hose can be detached readily.
Provided that the lip seal 346 is functioning sufficiently, it is possible to prevent
air leakage.
[0056] Now, a concrete installation procedure will be described. After connecting the indoor
unit B and the outdoor unit A by means of connection pipes, a pressure-resistant hose
13 forming a connection port is coupled in order to couple the two exhaust ports to
the exhaust port side of the vacuum pump. More specifically, a pressure-resistant
hose 13 which is branched by means of a filter 14 is connected respectively to one-touch
pipe joints 34a and 34b. Furthermore, the pressure-resistant hose 13 is also connected
to the service port section 8b. Next, the handle 18 of the vacuum pump is caused to
perform reciprocal movement, and when the pump has become difficult to work under
the operator's own strength and the operation is halted, it can be estimated that
the interior of the indoor unit B and the connection pipe 9 has reached a pressurized
state of approximately 5 kg/cm
2. This judgement is sufficiently easy to make after a little experience of the installation
work. Thereupon, it is possible to perform a leak inspection relating to the connection
pipe work, using soapy water, or the like. After leak inspection, the interior of
the indoor unit B and the connection pipe 9 are returned again to atmospheric pressure
by releasing the one-touch pipe joints 34a, 34b. Next, the respective branches of
the pressure-resistant hose 13 are connected to the one-touch pipe joints 36a and
36b. If the handle 18 of the vacuum pump is caused to perform reciprocal movement,
the pressure can be gradually reduced, and by means of the operator reading the number
of stroke movements from the display, it is possible to estimate when the interior
of the indoor unit B and the connection pipe 9 has reached a sufficient negative pressure
state. In other words, provided that the operator previously knows the relationship
between the length of the connection pipe 9 and the number of strokes of the vacuum
pump, from experience or from reference data, then he or she is able to judge a sufficient
negative pressure state inside the indoor unit B and connection pipe 9, by confirming
the number of strokes by means of the acceleration sensor.
[0057] Thereupon, by loosening the screw section 7a of the liquid-side two-way valve 7 and
introducing refrigerant gas from the outdoor unit A, the interior of the connection
pipes 9, 10 and the indoor unit B pipes are made to assume a slightly positive pressure
state (approximately 0.2 kgf/cm
2). The pressure-resistant hose 13 is detached from the service port section 8b, and
the screw section 7a of the liquid-side two-way valve 7 is then fully opened. Finally,
the screw section 8a of the gas-side three-way valve 8 is fully opened, thereby completing
the installation work relating to the installation of the air conditioner.
[0058] In the present embodiment, the internal volume of the indoor unit B piping including
the indoor heat exchanger 6, and the connection pipes 9, 10 was 2.5 litres. In the
vacuum pump, the internal volume of the cylinder space when the piston is at the top
dead center was 250 ml (27 dia. × 440 mm), and the total internal volume from the
cylinder outlet formed when the piston is at the bottom dead center, to the intake
port and exhaust port non-return valves, was 1.5 ml. These figures are taken to include
the port flow path space arising between the interior space of the cylinder and the
cylinder wall. The cylinder internal dead space formed when the piston is at the bottom
dead center was 3 ml. The relationship between V1a and V1b determined in a similar
manner to the first embodiment is V1a/V1b = 57. Fig. 20 shows a concrete illustration
of the V1b portion comprising the cylinder internal dead space and the total volume
of the internal space from the cylinder outlet when the piston is at the bottom dead
center to the intake port and exhaust port non-return valves. By adopting a structure
wherein an intake port and exhaust port are embedded in the cylinder side wall at
positions corresponding to the top dead center face and the bottom dead center face
of the cylinder main body, in such a manner that each pair of non-return valves are
directly connected, a design is achieved wherein the portion forming the dead space
in the pressure-reducing mechanism is a minimum, and furthermore, by providing the
non-return valves in the side wall of the cylinder, it possible to perform reciprocal
movement of the piston in a state where the under face of the cylinder 15 of the vacuum
pump is positioned on the ground, or the like. As a result, it is possible to improve
the operability of the vacuum pump for the operator.
[0059] In this case, by following the aforementioned work procedure, it was possible to
achieve 22 torr using the vacuum pump, by performing 70 stroke's of reciprocal movement
of the handle. Fig. 21 shows the progress of the state of pressure reduction, in the
form of the relationship between the number of strokes and the internal pressure.
After 60 strokes, the pressure was 30 torr or less, and although the progress of pressure
reduction was confirmed up to 80 strokes, the vacuum level attained reached a state
of equilibrium at 70 strokes and did not advance further thereafter. Consequently,
it can be seen that when a vacuum pump according to the present embodiment is applied
to a system having an internal volume of 2.5 litres, then 70 strokes is the general
standard for the attained vacuum level. To obtain an accurate figure, the vacuum level
was monitored separately using a digital pressure sensor.
[0060] In the present embodiment, by initially using the exhaust port side of the vacuum
pump having a readily detachable connection device, as a pressurizing pump, it is
possible to perform satisfactory leakage inspection accompanying installation work.
Thereupon, by attaching pressure-resistant hoses to the intake port side, it is possible
to use the pump as a conventional pressure reducing vacuum pump. In this way, by simply
changing the installation of the pressure-resistant hose section forming a coupling
section for the respective exhaust ports or intake ports, between the exhaust port
side or the intake port side, it is possible to use separate active functions of the
vacuum pump. Moreover, since only one pressure-resistant hose is required, it is possible
to achieve a system that is more compact than that described in the second embodiment.
[0061] In the present embodiment, one-touch joints as illustrated in Fig. 19 were used for
the readily attachable and detachable connection devices, but the readily attachable
and detachable connection devices which can be used in the present invention are not
limited to this. In addition to this, it is also possible to use a tube coupler, or
the like, which does not comprise a self-sealing mechanism.
[0062] Installation was completed according to the procedures of the first, second and third
embodiments, for an air conditioner using R410A as the refrigerant and an ester oil
as the cooling unit oil, and reliability testing was carried out for 5000 hours, by
setting the output temperature of the compressor to an overload condition of 115°C,
and setting both the indoor unit and the outdoor unit to high-temperature cooling
conditions of 40°C. No particular irregularities were observed as a result of this
testing.
[0063] In the pressure reducing mechanism of a vacuum pump according to the present invention,
the interior of the cylinder can be maintained constantly at a reduced pressure state
by operating the piston, but the cylinder internal dead space formed when the piston
is at the bottom dead center and the spatial volume from the cylinder outlet to the
non-return valves on the intake port side and the exhaust port side create a dead
space. The cylinder internal dead space comprises the small gap formed when the piston
meets the plane of the bottom dead center of the cylinder, and the intake port and
exhaust port flow paths formed inside the cylinder wall. Therefore, in terms of the
attained vacuum level, the relationship between via, which is the total volume of
the internal volume of the cylinder space, the cylinder internal dead space formed
when the piston is at the bottom dead center, and the volume of the internal space
from the cylinder outlet to the two non-return valves of the intake ports and exhaust
ports, and V1b which is the total of the cylinder internal dead-space formed when
the piston is at the bottom dead center, and the volume of the internal space from
the cylinder outlet to the two non-return valves of the intake ports and exhaust ports,
is very important. Moreover, if the cylinder internal dead space formed when the piston
is at the bottom dead center, and the volume of the space from the cylinder outlet
to the two non-return valves of the intake ports and exhaust ports, is clearly greater
than the aforementioned dead space, then at the top dead center of the piston, rather
than functioning as a vacuum pump, the system conversely reduces the negative pressure
level, and therefore, desirably, the dead space formed at the top dead center and
the bottom dead center should be approximately equal. In other words, the reason why
the dead space formed at the bottom dead center of the piston is a more crucial element
in the level of vacuum attained than that formed at the top dead center, is because
the volume of the cylinder space is reduced by the volume occupied by the supporting
shaft.
[0064] It was observed that, if a design is adopted whereby the relationship between V1a,
which is the total volume of the internal volume of the cylinder space formed when
the piston is at the top dead center, the cylinder internal dead space formed when
the piston is at the bottom dead center, and the volume of the internal space from
the cylinder outlet to the two non-return valves of the intake ports and exhaust ports,
and V1b which is the total of the cylinder internal dead space formed when the piston
is at the bottom dead center, and the volume of the internal space from the cylinder
outlet to the two non-return valves of the intake ports and exhaust ports, is V1a/V1b
≥ 40, and if the leakage at the non-return valves is controlled to some extent, then
it is possible to achieve a pressure of 30 torr or less, satisfactorily, by performing
reciprocal movement of the handle of the vacuum pump. In view of the long-term reliability
of the refrigeration cycle, even if there is no leaking of the airtightness in the
design, a relationship of V1a/V1b ≥ 40 is required. If the relationship V1a/V1b is
too large, then although there will be no impediment to the level of vacuum attained,
the vacuum pump will be become bulky and heavy and portability of the device will
be impaired. Moreover, the operation for performing reciprocal movement of the handle
will be impaired.
[0065] It can be seen that the number of strokes of the vacuum pump required in the installation
of an air conditioner according to the present invention is determined by the relationship
between the internal volume of the piping of the indoor unit and the connection pipes,
and the internal volume of the cylinder space. If the internal volume of the indoor
unit piping and the connection pipes is 1.5 litres, and the internal volume of the
cylinder space is 150 or 250 ml, then a state of equilibrium is reached after performing
approximately 40 strokes of reciprocal movement, and if the internal volume of the
indoor unit and the connection pipes is 2.5 litres, and the internal volume of the
cylinder space is 250 ml, then a state of equilibrium is reached after performing
approximately 70 strokes of reciprocal movement. Therefore, by establishing these
relationships in a database, it is possible for an operator to estimate and deduce
the general state of the vacuum level attained, by controlling the number of strokes
of the vacuum pump.
[0066] The shaft seal used in the present invention is an elastomer with a hardness of approximately
60 - 90 in a spring-type hardness test (type A). More specifically, it is also suitable
to use CR, EPDM, NBR, or the like, in addition to HNBR. Moreover, in the present embodiment,
the shaft seals had a dual O-ring structure and formed a contact with the supporting
shaft at two points, and in this case, the contact point on the outer side has the
action of removing dust adhering to the supporting shaft when the supporting shaft
is outside the cylinder. Moreover, even in the case of sudden movements of the supporting
shaft, since there are two or more contact points with the seals, then even if an
air leakage occurs on one side, this can be sealed off by the contact point on the
other side.
[0067] As a non-return valve structure for the exhaust port side used in the present invention,
in addition to the construction described in the embodiments, it is also possible
to use an opening and closing valve structure by moving a movable member consisting
of a small and lightweight metal ball inside a pipe. For the resin, in addition to
nylon, it is also possible to fluorine based resins, such as PFA, PVDF, or the like,
or PPS. In the non-return valves used in the present invention, the minimum operating
pressure differential is more important on the intake port side than on the exhaust
port side. In other words, the exhaust port side gradually moves towards a greater
pressure differential as the vacuum pump is operated, but on the intake port side,
conversely, the pressure differential between the indoor unit and connection pipes
and the interior of the cylinder becomes smaller. Therefore, it is desirable that
the non-return valves on the intake port side should close and seal even at a small
pressure differential, and more specifically, that the minimum operating pressure
differential should be 10 torr or less. More desirably, the fluid leakage volume at
a pressure differential of 1 kgf/cm
2 should be 1 ml/min or less. This is because operability is impaired, in such a manner
that as soon as the operator stops operating the handle of the vacuum pump, the vacuum
level attained thus far drops suddenly. More specifically, it is desirable that the
non-return valve shuts off the flow path by pressing a resin film against a valve
seating member, by means of a compression coil spring such as that used in the present
embodiment. In this case, the spring constant of the compression coil spring was 0.01
- 0.04 N/mm. If the spring constant is less than 0.01 N/mm, then depending on the
direction of the vacuum pump during operation, the compression coil spring may be
affected by gravity and may fail to function satisfactorily.
[0068] In the present embodiment, the vacuum pump was operated using a manual handle, but
it is also possible to adopt a mechanical construction, wherein a pedal is provided
and the operation of the piston is synchronized to the pedal. Taking the global environment
into consideration, the fact that a satisfactory level of vacuum can be obtained by
using a handle or a pedal, as opposed to an electric pump as in the prior art, brings
significant benefits in terms of reducing the environment load when installing an
air conditioner.
(Fourth embodiment)
[0069] The construction of the refrigerating cycle illustrating an air conditioner according
to the fourth embodiment is the same as that shown in Fig. 1, which is a refrigerating
cycle diagram relating to the first embodiment.
[0070] In the separate type air conditioner of the present embodiment the outdoor unit A
and the indoor unit B are connected in a ring configuration by connection pipes 9,
10, a quantity of refrigerant gas required in order to display a prescribed cooling
effect is previously filled into the pipes of the outdoor unit A, and a screw section
7a of a liquid-side two-way valve 7 and a screw section 8a of a gas-side three-way
valve 8 are closed. After installation for connecting the indoor unit B to the outdoor
unit A by means of connection pipes 9, 10, the vacuum pump P according to the present
invention as illustrated in Fig. 16 is used to perform a vacuum process in order to
reduce the oxygen in air, which must be evacuated from the respective interiors of
the indoor unit B and the connection pipes 9, 10, from the viewpoint of the reliability
of the refrigerating cycle, to a satisfactory level.
[0071] In other words, the connection pipes 9, 10 connected to the indoor unit B are connected
to the liquid-side two-way valve 7 and gas-side three-way valve 8 of the outdoor unit
A, whereupon the vacuum pump P is coupled to a service port section 8b of the gas-side
three-way valve 8 of the outdoor unit A by means of a pressure-resistant hose 13 which
forms a coupling port section for coupling the two exhaust ports 31 into one. The
pressure-resistant hose 13 is provided with a filter section 14 at an intermediate
position therein.
[0072] Fig. 16 is a schematic diagram which gives a detailed illustration of the construction
of the vacuum pump P and the connection path of the pressure-resistant hose according
to the present invention. As the handle 18 is operated upwards and downwards and travels
in either the a direction or the b direction, the pressure difference between the
two chambers gradually declines from the initial differential, and the intake port
side 31 is set to a negative pressure state.
[0073] An acceleration sensor 181 and primary electric cell 182 as illustrated in Fig. 3
and Fig. 4 are built into the handle 18 to serve as a sensor which counts (detects)
each stroke of the piston 27 in the a direction and b direction, and allows the operator
to estimate the negative pressure state on the intake port 31 side. Furthermore, a
display 183 is provided on the upper surface of the handle 18 in such a manner that
the negative pressure state on the intake port 31 side can be displayed on the display
183 on the basis of detection signals from the acceleration sensor 181. Moreover,
the intake ports 31 and exhaust ports 30 are disposed respectively in positions bordering
the top dead center and bottom dead center of the two chambers 26a, 26b of the cylinder
15, and the total weight of the vacuum pump P is -approximately 1 kg.
[0074] Fig. 3 is a schematic view showing the principal part of the construction of the
handle 18, and Fig. 4 is a schematic constitutional view of the acceleration sensor
181. The acceleration sensor 181 is composed of a thinly formed sensor section 41
consisting of a silicon semiconductor 40, and a weight section 42 having a large surface
area. In the operation of the acceleration sensor 181, when the piston 27 arrives
at the top dead center or the bottom dead center of the cylinder 15 due to the manual
operation thereof, it impacts with the wall of the cylinder 15 and the stroke movement
of the handle 18 halts, at which time an acceleration G is generated by this impact
and the weight section 42 receives this acceleration and the sensor section 41 is
caused to distort.
[0075] This distortion in turn causes a change in the electrical resistance of the diffused
layer 43 formed on the top of the sensor section 41. In other words, a construction
is adopted wherein the acceleration sensor 181 detects the stress caused by distortion
of the sensor section 41 due to the acceleration G, by means of a piezo effect of
the sensor section 41, converting this into a voltage output by means of a bridge
circuit, and if this output exceeds a certain prescribed value, then one stroke can
be counted. In the diagram, 44 is an electrode, and 45 is a case comprising a base
plate onto which the electrode 44 is fixed.
[0076] Fig. 22 is a flowchart of the procedure whereby the acceleration sensor 181 counts
the reciprocal movements of the piston 27 and the estimated negative pressure state
on the intake port 31 side is displayed. A signal output based on the piezo effect
in the sensor section 41 is amplified by the amplifying section 50 and after unwanted
components have been removed from the output by a filter section 51, the signal is
passed through an A/D converter 52 for converting the output into a digital signal,
whereupon the negative pressure state at the intake port 31 side is calculated by
an operating unit 53, and finally, the count is displayed on a display section 183.
[0077] Thereupon, the operation of the vacuum pump P is described. Firstly, if the handle
18 is pulled in the a direction (towards the top dead center), then the air inside
the connection pipe 9, the indoor unit B and the connection pipe 19 is drawn in from
the service port section 8b, via the pressure-resistant hose 13 and filter section
14, and into chamber 26b inside the cylinder 15, by means of the intake non-return
valve 31b of the intake port 31, whilst conversely, the air in the chamber 26a inside
the cylinder 15 is exhausted into the atmosphere via the exhaust side non-return valve
30a.
[0078] Thereupon, when the handle 18 is pushed in the b direction (towards the bottom dead
center), the air inside the connection pipe 9, the indoor unit and the connection
pipe 10 is drawn in from the service port section 8b, via the pressure-resistant hose
13 and filter section 14, and into the chamber 26b inside the cylinder 15 by means
of the intake side non-return valve 31a of the intake port, whilst conversely, the
air in the chamber 26a inside the cylinder 15 is exhausted into the atmosphere via
the exhaust non-return valve 30b of the exhaust port 30.
[0079] Thereupon, the reciprocal movement of the handle 18 is repeated in such a manner
that the handle 18 is pulled again in the a direction (towards to the top dead center),
and the piston 17 performs synchronized movement. In this case, the interior of the
cylinder 15 constantly reduces in pressure, whether the piston moves in direction
a or direction b, whilst the four non-return valves are switched alternately, and
ultimately, a sufficient negative pressure state can be achieved. In strict terms,
it is possible to continue the pressure reducing mechanism, as long as it is possible
to generate a pressure differential between the interior of the pressure-resistant
hose 13 and the chambers 26a or 26b inside the cylinder when performing reciprocal
movement of the handle 18. Therefore, the non-return valves 31a and 31b provided at
the intake ports 31 are required to have a low minimum operating pressure differential.
In the case of a non-return valve as in the present embodiment, the factor determining
this minimum operating pressure differential is the spring constant of the compression
coil spring member 203.
[0080] when the vacuum pump P performs this series of reciprocal movements, the operator
causes the piston 27 to impact respectively with the inner wall of the cylinder 15
at the top dead center and the bottom dead center, respectively, and in this case,
the operator is able to cause an acceleration of 1 to 5 G. This acceleration G is
transmitted to the handle 18 via the supporting shaft 17. Consequently, the acceleration
sensor 181 detects the generated acceleration G and is able to display the number
of strokes of reciprocal movement, on the display 183.
[0081] When it is used initially, the vacuum pump P generates a large pressure differential
between the chambers 26a and 26b inside the cylinder 15, but as the piston 27 performs
reciprocal movement, this pressure differential state is gradually attenuated. In
this case, the shaft seals 21a, 21b provide a satisfactory guarantee of the pressure
differential state between the negative pressure (30 torr or less) inside the cylinder
15 and the external atmosphere (760 torr), and in order to prevent leaking of airtightness,
as far as possible, the seals are formed by dual O-rings. By adopting a dual structure
in this way, it is possible to prevent foreign material which is liable to adhere
to and infiltrate inside the seal section when the supporting shaft is operated. Furthermore,
the shaft seal 22 provides a sufficient guarantee of a differential pressure state
created when the piston 27 is made to perform reciprocal movement, by means of a single
O-ring.
[0082] A specific installation procedure for an air conditioner is now described. Connection
pipes 9 and 10 are connected to the indoor unit B and further connected to the liquid-side
two-way valve 7 and gas-side three-way valve 8 of the outdoor unit A, whereupon the
vacuum pump P is coupled by the pressure-resistant hose 13 to the service port section
8b of the gas-side three-way valve 8 of the outdoor unit A. In this way, by attaching
the pressure-resistant hose 13 of the vacuum pump P to the service port section 8b,
the interior of the pressure-resistant hose 13 becomes coupled to the indoor unit
B and the interior of the connection pipes 9, 10.
[0083] Thereupon, the handle 18 of the vacuum pump P is caused to perform reciprocal movement,
and the operator is able to estimate and determine that the interior of the indoor
unit B and the connection pipe 9 has reached a sufficient negative pressure state
by reading out the number of strokes of reciprocal movement performed from the display
183. Then, the screw section 7a of the liquid-side two-way valve 7 is loosened slightly,
and refrigerant gas filled into the outdoor unit is introduced, thereby setting the
interior of the connection pipes 9, 10 and the indoor unit side piping to a slight
positive pressure state (approximately 0.2 kgf/cm
2). Subsequently, the pressure-resistant hose 13 is detached from the service port
section 8b and the service port section 8b is automatically closed. The screw section
7a of the liquid-side two-way valve 7 is rotated by a further 1/4 turn, and a positive
pressure state (approximately 3 - 6 kgf/cm
2) is applied again to recheck for leaking in the connection pipe regions. Finally,
the screw section 7a of the liquid-side two-way valve 7 is opened completely, and
the screw section 8a of the gas-side three-way valve 8 is opened fully, whereby the
installation tasks for the installation of the air conditioner are completed.
[0084] In the present embodiment, the internal volume of the indoor unit piping, including
the indoor heat exchanger 6, and the connection pipes 9, 10, was 2.5 litres. In the
vacuum pump, the internal volume of the cylinder space when the piston is at the top
dead center was 250 ml (27 mm diameter × 440 mm), and the total internal volume from
the cylinder outlet at the exhaust port 30 formed when the piston is at the bottom
dead center, to the two intake port side and exhaust port side non-return valves,
was 1.5 ml. These figures are taken to include the port flow path space arising in
the main wall of the cylinder 15.
[0085] The cylinder internal dead space formed when the piston 27 is at the bottom dead
center was 3 ml. Taking Via to be the total volume of the internal volume of the cylinder
space formed when the piston 27 is at the top dead center, the cylinder internal dead
space formed when the piston is at the bottom dead center, and the volume of the internal
space from the cylinder outlet to the two non-return valves of the intake ports and
exhaust ports, and taking V1b to be the total volume of the cylinder internal dead
space formed when the piston is at the bottom dead center, and the volume of the internal
space from the cylinder outlet to the two non-return valves of the intake ports and
exhaust ports, then the relationship between V1a and V1b is V1a/V1b = 57.
[0086] Fig. 20 is a concrete illustration of the V1b region comprising the cylinder internal
dead space and the total internal volume of the space from the cylinder outlet when
the piston 27 is at the bottom dead center to the two non-return valves on the intake
port side and the exhaust port side. By adopting a system structure wherein intake
ports 31 and exhaust ports 30 are embedded in the cylinder side wall at positions
corresponding to the top dead center and the bottom dead center of the cylinder main
body, in such a manner that the pair of exhaust non-return valves 30a, 30b and the
pair of intake non-return valves 31a, 31b are directly, connected, respectively, a
design is achieved wherein the portion forming the dead space in the pressure-reducing
mechanism is a minimum, and furthermore, it possible to perform reciprocal movement
of the piston 27 in a state where the under face of the cylinder 15 of the vacuum
pump P is placed on the ground, or the like. As a result, it is possible to improve
the operability of the vacuum pump for the operator, and it is also possible for the
pump to handled in a normal way, without the need for special caution.
[0087] The vacuum pump P was able to achieve 22 torr by performing the operation according
to the aforementioned procedure, and by performing 70 strokes of reciprocal movement
of the handle 18. Fig. 21 shows the progress of the state of pressure reduction, in
the form of the relationship between the number of strokes on the horizontal axis
and the internal pressure on the vertical axis. The progress of pressure reduction
was confirmed up to 80 strokes, but the vacuum level attained reached a state of equilibrium
at 70 strokes and did not advance further thereafter. Consequently, it can be seen
that when a vacuum pump according to the present embodiment is applied to a system
having an internal volume of 2.5 litres, then 70 strokes is the general standard for
the attained vacuum level.
[0088] The accurate figure of the vacuum level was monitored separately using a digital
pressure sensor. The number of strokes can be counted by the operator is his or her
head, but if the number of strokes can be counted by an acceleration sensor as in
the present embodiment and displayed in a reliable manner, then this is very convenient
in operational terms. For example, it makes it possible to prevent situations where
someone starts to speak to the operator whilst he or she is counting, thereby making
the operator lose count.
[0089] In the present embodiment, the acceleration sensor 181 is provided inside the handle
18, but the invention is not limited to this. In other words, since the piston 27
which impacts with the cylinder 15 is fixed to the supporting shaft 17, and the supporting
shaft 17is fixed to the handle 18, then it is possible to achieve the initial object
by providing the sensor on either the piston, the supporting shaft or the handle.
(Fifth embodiment)
[0090] Fig. 23 is a schematic constitutional view showing an acceleration sensor provided
on the handle of a vacuum pump according to a fifth embodiment of the present invention.
The present embodiment uses a distortion resistance mechanism for the acceleration
sensor method, and with the exception of this, the construction of the vacuum pump
is the same as that of the fourth embodiment, and hence detailed description thereof
is omitted here and only the different parts are explained.
[0091] A construction is adopted wherein a supporting pillar 132 is provided inside a case
131, and a weight 133 is provided at the front end of the supporting pillar 132 and
is held by an arm 134 in a cantilever fashion. Components forming strain gauges 135
are attached to the front and rear sides of the surface of the arm 134. Fig. 24 shows
the construction of this strain gauge 135. An aluminium metal foil 152 of 3 µm thickness
is adhered onto a polyimide insulating film 151, and after patterning by hot etching
in order to obtain a required shape and resistance values, it is covered with a protective
film. Numerals 153 denote lead wires.
[0093] In the present embodiment, the internal volume of the indoor unit piping, including
the indoor heat exchanger 6, and the connection pipes 9, 10, was 1.5 litres. In the
vacuum pump, the internal volume of the cylinder space when the piston 27 was at the
top dead center was 200 ml (27 mm diameter × 350 mm), the total internal volume of
the space from the cylinder outlet formed when the piston is at the bottom dead center
to the two non-return valves on the intake port side and exhaust port side was 1.5
ml, and the cylinder internal dead space formed when the piston is at the bottom dead
center was 3 ml. This is taken to include the port flow path space arising in the
main wall of the cylinder 13. If the relationship between the total internal volume
V1a and the total internal volume V1b is determined, then V1a/V1b = 45, similarly
to the fourth embodiment.
[0094] In the present embodiment, an installation operation for an air conditioner was carried
out and by performing 40 strokes of reciprocal movement of the handle of the vacuum
pump P, a pressure of 28 torr was reached. Fig. 26 illustrates the state of progress
of the pressure reduction, in the form of a relationship between the number of strokes
and the internal pressure. The progress of the pressure reduction was checked until
50 strokes had been performed, although the pressure level attained reached a state
of equilibrium after 40 strokes and did not progress further thereafter. Consequently,
it can be seen that when a vacuum pump according to the present embodiment is applied
to a system having an internal volume of 1.5 litres, then 40 strokes is the general
standard for the attained vacuum level. To obtain an accurate figure, the vacuum level
was monitored separately using a digital pressure sensor.
[0095] In the present embodiment, an electronic distortion resistance mechanism was used
for the acceleration sensor, but it would also be possible use a piezoelectric mechanism
or electrostatic capacitance mechanism.
(Sixth embodiment)
[0096] Fig. 27 is a schematic diagram wherein a counter containing an acceleration sensor
is provided in the handle of a vacuum pump according to the present invention, and
Fig. 28 is a schematic diagram for further illustrating the mechanism of the acceleration
sensor. The present embodiment also uses a mechanical system for the acceleration
sensor, and the remaining construction of the vacuum pump is similar to that in the
fourth embodiment and detailed description thereof is omitted, only the different
parts being described here.
[0097] Here, a construction is adopted wherein a counter 210 containing an acceleration
sensor is detachably attached to a portion of the handle 18 of a vacuum pump, by means
of a hook and loop fastener 220. The internal mechanism of the counter 210 is designed
in such a manner that a pendulum 212 can move in an upward and downward direction
about a fulcrum 211, as illustrated in Fig. 28. A magnet 213 is attached to the front
end portion of the pendulum 212. Moreover, the upward and downward motion of the pendulum
212 can be controlled by the spring force of a wire spring 214.
[0098] One end of the wire spring 214 is fixed to the main body of the counter 210 by means
of a fixing section 215, and the other end thereof is fixed to the pendulum 212 by
means of a fixing section 216. Moreover, a reed switch 217 is provided in a position
corresponding to that of the magnet 213 when the pendulum 212 has reached its lowermost
position. In addition, a display and a primary electric cell forming a power source
are provided in the counter 210. A reed switch 217 comprises a pair of reeds made
from magnetic material, which are sealed inside a glass tube with an inert gas. The
switch performs a repeating on and off operation under the action of an external magnetic
field.
[0099] In the aforementioned embodiment, each time the piston of the vacuum pump is caused
to perform a downward stroke and reaches the bottom dead center, impacting with the
inner wall of the cylinder, the pendulum 212 also reaches its lowermost position,
once, the reed switch 217 is switched on by the magnet 213, and thus the stroke is
counted. Moreover, each time that the piston is caused to perform an upward stroke
and reaches the top dead center, impacting with the inner wall of the cylinder, the
pendulum 212 also reaches its lowermost position, once, and the reed switch 217 is
switched on by the magnet 213, and hence the stroke is counted. By optimising the
diameter and length of the wire spring 214 in accordance with the impact acceleration
G accompanying the stroke movement of the piston, it was possible to prevent a state
where double counting occurs or where a count is skipped.
(Seventh embodiment)
[0100] Fig. 29 is a schematic diagram showing the mechanism of the acceleration sensor of
a vacuum pump according to a seventh embodiment of the present invention, and Fig.
30 is a schematic diagram for further describing the mechanism of the acceleration
sensor. This embodiment also uses a mechanical system for the method of the acceleration
sensor, and the remaining construction of the vacuum pump is the same as that in the
fourth embodiment, and hence detailed description thereof is omitted and only the
different parts are described here.
[0101] In the present embodiment, similarly to the fifth embodiment, a counter 230 having
a built-in acceleration sensor is detachably attached to a portion of the handle 18
of a vacuum pump, by means of a velcro fastener 240. As shown in Fig. 30, in the internal
mechanism of the counter 230, a rotatable arm 232 is installed in such a manner that
it can move upwards and downwards about a rotating axle 231. One end of a wire spring
233 is fixed by means a fixing section 234 to the main body of the counter 230 and
the other end of the spring is fixed by a fixing section 2321 to the arm 232, in such
a manner that the arm 232 is caused to rock in an upward direction.
[0102] An upper contact switch 235 and a lower contact switch 236 of a contact pressing
type are provided in order to generate an ON state of an electrical circuit when the
arm 232 reaches a lower position. The upper contact switch 235 is connected to a lead
wire via a terminal section 2351, and the end portion thereof is bent into an approximate
right-angled shape. Furthermore, a lead wire is attached to a terminal section 2361
of the lower contact switch 236. An upper stopper 237 is provided in order to restrict
the position of the arm 232 in the upwards direction, and a lower stopper 238 is provided
in order to restrict the position thereof in the downward direction. Besides this,
a display and a primary cell forming an electrical power source are provided in the
counter 230.
[0103] In the embodiment described above, when the piston of the vacuum pump performs a
downward stroke movement and reaches the bottom dead center, impacting with .the internal
wall of the cylinder, the arm 232 also reaches the lower position, once, thereby causing
the upper contact switch 235 to contact with the lower contact switch 236, switching
the circuit on and counting the stroke movement. Furthermore, when the piston performs
an upward stroke movement and reaches the top dead center, impacting with the internal
wall of the cylinder, the arm 232 also reaches the lower position, once, thereby causing
the upper contact switch 235 to contact with the lower contact switch 236, switching
the circuit on and counting the stroke movement. By optimising the diameter and length
of the wire spring 233 in accordance with the impact acceleration G accompanying the
stroke movement of the piston, it was possible to prevent a state where double counting
occurs or where a count is skipped.
(Eighth embodiment)
[0104] Fig. 31 is a schematic diagram showing the mechanism of the acceleration sensor of
a vacuum pump according to an eighth embodiment of the present invention, and Fig.
32 is a schematic diagram for further describing the mechanism of the acceleration
sensor. This embodiment also uses a mechanical system for the method of the acceleration
sensor, and the remaining construction of the vacuum pump is the same as that in the
fourth embodiment, and hence detailed description thereof is omitted and only the
different parts are described here.
[0105] In the present embodiment, similarly to the fifth embodiment, a counter 250 containing
a built-in acceleration sensor is detachably attached to a portion of the handle 18
of a vacuum pump, by means of a velcro fastener 250. As shown in Fig. 32, in the internal
mechanism of the counter 250, a rotatable arm 252 is installed in such a manner that
it can move upwards and downwards.about a rotating axle 251, and a circular metal
component 2521 is provided on the front end portion of the arm.
[0106] One end of a wire spring 253 is fixed by means a fixing section 254 to the main body
of the counter 250 and the other end of the spring is fixed by a fixing section 2522
to the arm 252, in such a manner that the arm 252 is caused to rock in an upward direction.
A right-hand contact switch 255 and a left-hand contact switch 256 forming a contact
conducting type are provided in order to generate an ON state of an electrical circuit
by means of the circular metal component 2521 at the front end of the arm, when the
arm 252 reaches a lower position. An upper stopper 257 is provided in order to restrict
the position of the arm 252 in the upwards direction, and a lower stopper 258 is provided
in order to restrict the position thereof in the downward direction. Besides this,
a display and a primary cell forming an electrical power source are provided in the
counter 250.
[0107] In the embodiment described above, when the piston of the vacuum pump performs a
downward stroke movement and reaches the bottom dead center, impacting with the internal
wall of the cylinder, the arm 252 also reaches the lower position, once, whereby the
right-hand contact switch 255 and the left-hand contact switch 256 are caused to assume
a state of electrical connection by means of the circular metal component 2521, thus
switching the circuit on and counting the stroke movement. Furthermore, when the piston
performs an upward stroke movement and reaches the top dead center, impacting with
the internal wall of the cylinder, the arm 252 also reaches the lower position, once,
whereby the right-hand contact switch 255 and the left-hand contact switch 256 are
caused to assume a state of electrical connection by means of the circular metal component
2521, thus switching the circuit on and counting the stroke movement. By optimising
the diameter and length of the wire spring 253 in accordance with the impact acceleration
G accompanying the stroke movement of the piston, it was possible to prevent a state
where double counting occurs or where a count is skipped.
[0108] Installation was completed according to the procedures of the aforementioned embodiments,
for an air conditioner using R410A as the refrigerant and an ester oil as the cooling
unit oil, and reliability testing was carried out for 5000 hours, by setting the output
temperature of the compressor to an overload condition of 115°C, and setting both
the indoor unit and the outdoor unit to high-temperature cooling conditions of 40°C.
No particular irregularities were observed as a result of this testing.
[0109] In the pressure reducing mechanism of a vacuum pump P according to the present invention,
the interior of the cylinder 15 can be maintained constantly at a reduced pressure
state by operating the piston 27, but the cylinder internal dead space formed when
the piston is at the bottom dead center and the spatial volume from the cylinder outlet
to the two non-return valves on the intake port side and the exhaust port side create
a dead space. The cylinder internal dead space comprises the small gap formed when
the piston meets the plane of the bottom dead center of the cylinder, and the intake
port and exhaust port flow paths formed inside the cylinder wall.
[0110] Therefore, with regard to the attained vacuum level, the relationship between V1a,
which is the total volume of the internal volume of the cylinder space, the cylinder
internal dead space formed when the piston is at the bottom dead center, and the volume
of the internal space from the cylinder outlet to the two non-return valves of the
intake ports and exhaust ports, and V1b which is the total of the cylinder internal
dead space formed when the piston is at the bottom dead center, and the volume of
the internal space from the cylinder outlet to the two non-return valves of the intake
ports and exhaust ports, is very important.
[0111] Moreover, if the cylinder internal dead space formed when the piston is at the bottom
dead center, and the volume of the space from the cylinder outlet to the two non-return
valves of the intake ports and exhaust ports, is clearly greater than the aforementioned
dead space, then at the top dead center of the piston, rather than functioning as
a vacuum pump, the system conversely reduces the negative pressure level, and therefore,
desirably, the dead space formed at the top dead center and the bottom dead centers
should be approximately equal. In other words, the reason why the dead space formed
at the bottom dead center of the piston is a more crucial element in the level of
vacuum attained than that formed at the top dead center, is because the spatial volume
of the cylinder 15 is reduced by the volume occupied by the supporting shaft 17.
[0112] It was observed that, if a design is adopted whereby the relationship between V1a,
which is the total volume of the internal volume of the cylinder space formed when
the piston is at the top dead center, the cylinder internal dead space formed when
the piston is at the bottom dead center, and the volume of the internal space from
the cylinder outlet to the two non-return valves of the intake ports and exhaust ports,
and V1b which is the total of the cylinder internal dead space formed when the piston
is at the bottom dead center, and the volume of the internal space from the cylinder
outlet to the two non-return valves of the intake ports and exhaust ports, is V1a/V1b
≥ 40, and if the leakage at the non-return valves is controlled to some extent, then
it is possible to achieve a pressure of 30 torr or less, satisfactorily, by performing
reciprocal movement of the handle of the vacuum pump P.
[0113] In view of the long-term reliability of the refrigeration cycle, even if there is
no leaking of the airtightness in the design, a relationship of V1a/V1b ≥ 40 is required.
If the relationship V1a/V1b is too large, then although there will be no impediment
to the level of vacuum attained, the vacuum pump will be become bulky and heavy and
portability of the device will be impaired. Moreover, the operation for performing
reciprocal movement of the handle 18 will be impaired.
[0114] It can be seen that the number of strokes of the vacuum pump P required in the installation
of an air conditioner according to the present invention is determined by the relationship
between the internal volume of the piping of the indoor unit and the connection pipes
9, 10, and the internal volume of the cylinder 15 space. If the internal volume of
the indoor unit piping and the connection pipes 9, 10 is 1.5 litres, and the internal
volume of the cylinder 15 space is 200 ml, then a state of equilibrium is reached
after performing approximately 40 strokes of reciprocal movement, and if the internal
volume of the indoor unit and the connection pipes 9, 10 is 2.5 litres, and the internal
volume of the cylinder 15 space is 250 ml, then a state of equilibrium is reached
after performing approximately 70 strokes of reciprocal movement. Therefore, by establishing
these relationships in a database, it is possible for an operator to estimate and
deduce the general state of the vacuum level attained, by controlling the number of
strokes of the vacuum pump by means of the sensor according to the present invention.
[0115] The shaft seal used in the present invention is an elastomer with a hardness of approximately
60 - 90 in a spring-type hardness test (type A). More specifically, it is also suitable
to use CR, EPDM, NBR, or the like, in addition to HNBR. Moreover, in the present embodiment,
the shaft seals 21a and 21b had a dual O-ring structure and formed a contact with
the supporting shaft 17 at two points, and in this case, the contact point on the
outer side has the action of removing dust adhering to the supporting shaft when the
supporting shaft is outside the cylinder. Moreover, even in the case of sudden movements
of the supporting shaft, since there are two or more contact points with the seals,
then even if an air leakage occurs on one side, this can be sealed off by the contact
point on the other side.
[0116] As a non-return valve structure for the exhaust ports 30 used in the present invention,
in addition to the construction described in the embodiments, it is also possible
to use an opening and closing valve structure by moving a movable member consisting
of a small and lightweight metal ball inside a pipe. For the resin, in addition to
nylon, it is also possible to fluorine based resins, such as PFA, PVDF, or the like,
or PPS. In the non-return valves used in the present invention, the minimum operating
pressure differential is more important on the intake port 31 side than on the exhaust
port 30 side. In other words, the exhaust port 30 side gradually moves towards a greater
pressure differential as the vacuum pump P is operated, but on the intake port 31
side, conversely, the pressure differential between the indoor unit and connection
pipes 9, 10 and the interior of the cylinder 15 becomes smaller.
[0117] Therefore, it is desirable that the non-return valves on the intake port side should
close and seal even at a small pressure differential, and more specifically, that
the minimum operating pressure differential should be 10 torr or less. More desirably,
the fluid leakage volume at a pressure differential of 1 kgf/cm
2 should be 1 ml/min or less. This is because operability is impaired, in such a manner
that as soon as the operator stops operating the handle of the vacuum pump, the vacuum
level attained thus far drops suddenly. More specifically, it is desirable that the
non-return valve shuts off the flow path by pressing a resin film against a valve
seating member, by means of a compression coil spring such as that used in the present
embodiment. In this case, the spring constant of the compression coil spring was 0.01
- 0.04 N/mm. If the spring constant is 0.01 N/mm or less, then depending on the direction
of the vacuum pump during operation, the compression coil spring may be affected by
gravity and may fail to function satisfactorily.
[0118] In the present embodiment, the vacuum pump was operated using a manual handle, but
it is also possible to adopt a mechanical construction, wherein a pedal is provided
and the operation of the piston 27 is synchronized to the pedal. Taking the global
environment into consideration, the fact that a satisfactory level of vacuum can be
obtained by using a handle or a pedal, as opposed to an electric pump as in the prior
art, brings significant benefits in terms of reducing the environment load when installing
an air conditioner.
(Ninth embodiment)
[0119] Fig. 33 is a diagram of the construction of a refrigerating cycle of an air conditioner
in a ninth embodiment which is installed using a vacuum pump according to the present
invention and it is virtually the same as the construction of the first embodiment
illustrated in Fig. 1.
[0120] Fig. 34 is a schematic diagram for giving a detailed description of the construction
of the vacuum pump P and the connection path of the pressure-resistant hose 13 according
to the present invention. The structure of the vacuum pump P is such that an aluminium
piston 28 is disposed inside the main body of an aluminium cylinder 15 in such a manner
that it divides the interior of the cylinder 15 into an upper chamber 15a and a lower
chamber 15b, the piston 28 being coupled via a stainless steel supporting shaft 17
to an aluminium handle 18.
[0121] An acceleration sensor 181 and a primary electric cell 182 as illustrated in Fig.
3 and Fig. 4 are built into the handle 18, and a display 183 is provided on the surface
of the upper portion of the handle 18, in such a manner that a signal from the acceleration
sensor 181, which detects acceleration G caused by the impact of the piston 16 against
the cylinder 15 due to upward and downward movement thereof, is displayed on the display
183, thereby allowing the vacuum level of the vacuum pump P to be estimated. Furthermore,
an exhaust port 30 having a non-return valve 30a and an intake port 31 having a non-return
valve 31a are provided in the main wall of the cylinder 15, at positions corresponding
to the top dead center of the piston 28. The total weight of the main body of the
vacuum pump is approximately 1 kg.
[0122] Fig. 3 is a schematic view showing the principal part of the construction of the
handle 18, and Fig. 4 is a schematic constitutional view of the acceleration sensor
181. The acceleration sensor 181 is composed of a thinly formed sensor section 41
made from a silicon semiconductor 40, and a weight section 42 having a large surface
area. In the operation of the acceleration sensor 181, when the piston 28 arrives
at the top dead center or the bottom dead center of the cylinder 15 due to the manual
operation thereof, it impacts with the wall of the cylinder 15 and the stroke movement
of the handle 18 halts, at which time an acceleration G is generated by this impact
and the weight section 42 receives this acceleration and the sensor section 41 is
caused to distort.
[0123] This distortion in turn causes a change in the electrical resistance of a diffused
layer 43 formed on the top of the sensor section 41. In other words, a construction
is adopted wherein the acceleration sensor 181 detects the stress caused by distortion
of the sensor section 41 due to the acceleration G, by means of a piezo effect of
the sensor section 41, converting this into a voltage output by means of a bridge
circuit, and if this output exceeds a certain prescribed value, then one stroke can
be counted. In the diagram, 44 is an electrode, and 45 is a case comprising a base
plate onto which the electrode 44 is fixed.
[0124] The flowchart of the procedure until the acceleration sensor of the vacuum pump displays
a count display is similar to that shown in Fig. 22 corresponding to the fourth embodiment.
[0125] Fig. 5 is a schematic diagram of a non-return valve 30a provided at the exhaust port
30 and Fig. 6 is a sectional view along line A - A' in Fig. 5. The vacuum pump P is
composed in such a manner that when the piston 28 moves inside the cylinder 15, the
non-return valves 30a, 31a are directly coupled to the main wall of the cylinder 15
at the top dead center of the piston 28, and an open port 37 is provided in the main
wall of the cylinder 15 at the bottom dead center of the piston 28. An air filter
38 is provided at the front end of the open port 37. The non-return valve 30 at the
exhaust port has the structure shown in Fig. 5 and Fig. 6, whilst the non-return valve
31a at the intake port has the structure shown in Fig. 7.
[0126] The copper tube 191 of the non-return valve 30a is processed with roll grooves at
two points, and a brass valve seating member 192 is fixed in groove section 191a.
A nylon valve member 193 impacts with the valve seating member 192, and the movement
thereof is halted by a contact face with the valve seating member 192 in a section
having an oblique face. Moreover, in the opposite direction, the movement of the valve
member 193 is halted by the groove section 191b. Therefore, a non-return valve structure
is obtained wherein air only flows in the direction of the arrow.
[0127] The copper tube 201 of the non-return valve 31a is processed with roll grooves at
two points, and a brass valve seating member 202 is fixed to the groove section 201a.
A compression coil spring member 203 is joined to a film plate 204 and under the force
of the compression coil spring, the nylon film plate 204 is caused to impact with
a brass valve seating member 205, the fluid path being sealed by the contact between
the respective faces of the seating member 205 and the film plate 202, thereby achieving
a non-return valve structure wherein air is only able to flow in the direction of
the arrow.
[0128] Fig. 35 shows the detailed construction in a case where the piston 28 is situated
at the top dead center of the cylinder 15. Shaft seals 21a, 21b are disposed in the
region where the supporting shaft 17 comes into contact with the outer wall of the
cylinder 15, the seals being constituted by a dual O-rings made from HNBR. Shaft seal
22s, 22b consisting of dual O-rings made from HNBR are also provided in the portion
of the piston 28 where it contacts the inner wall of the cylinder 15.
[0129] A filter 14 having a similar construction to that of the fourth embodiment illustrated
in Fig. 9 is used.
[0130] Next, the operation of the vacuum pump P will be described. An indoor unit is previously
connected to a liquid-side two-way valve 7 and gas-side three-way valve 8 of an outdoor
unit. A pressure-resistant hose 13 of a gauge manifold 12 is connected to the intake
port 31 of the vacuum pump P and a pressure-resistant hose 11 thereof is connected
to the gas-side three-way valve 8.
[0131] Firstly, when the handle 18 is pulled in direction a (towards the top dead center),
the air in the upper chamber 15a in the cylinder 15 is exhausted from the exhaust
port 30into the atmosphere via the non-return valve 30a, whilst air is drawn into
the lower chamber 15b through the air filter 38 via the open port 37. Next, when the
handle 18 is pushed in the direction of arrow b (towards the bottom dead center),
the air inside the indoor unit and the connection pipes 9, 10 is drawn in from the
service port section 8b, via the pressure-resistant hose 11, gauge manifold 12, and
pressure-resistant hose 13, and into the upper chamber 15a of the cylinder 15 by means
of the intake port 31 and the non-return valve 31a, whilst, conversely, the air in
the lower chamber 15b is exhausted into the atmosphere from the open port 37, via
the air filter 38.
[0132] Thereupon, the handle 18 is caused to perform reciprocal movement in such a manner
that the handle is pulled up in the direction a (towards the top dead-center), and
the movement of the piston 28 is synchronized to this. A pressure reducing mechanism
is achieved constantly when the piston 28 is moved in the direction of arrow b, whilst
switching between the intake non-return valve 31a and the exhaust non-return valve
30a provided in the walls of the cylinder 15, and ultimately, a satisfactory negative
pressure state is achieved. In this case, since the lower chamber 15b is in a state
which allow it to take in air via the open port 37, then if the force on the handle
18 is relaxed when the handle 18 reaches the bottom dead center of the cylinder 15,
the piston 28 will return of its own accord with the application of little force,
so as to rise upwards in the direction of arrow a, in order to correct the pressure
differential existing between the upper chamber 15a and the lower chamber 15b.
[0133] In the vacuum pump P of the present embodiment, it is possible to continue the pressure
reducing mechanism, as long as it is possible to generate a pressure differential
between the interior of the pressure-resistant hose 13 and the upper chamber 15b of
the cylinder 15 when performing reciprocal movement of the handle 18. Therefore, the
non-return valve 31a provided at the intake port 31 is required to have a low minimum
operating pressure differential. In the case of a non-return valve as in the present
embodiment, the factor determining this minimum operating pressure differential is
the spring constant of the compression coil spring member 203.
[0134] Moreover, when the vacuum pump P performs a series of reciprocal movements, the operator
causes the piston 16 to impact respectively with the inner wall of the cylinder 15
at the top dead center and the bottom dead center, respectively, and in these impacts,
the operator is able to cause an acceleration of 1 to 5 G. This acceleration G is
transmitted to the handle 18 via the supporting shaft 17, and the acceleration sensor
181 detects this acceleration G and is able to display the number of strokes of reciprocal
movement on the display 183, thereby making it possible to estimate the level of vacuum.
[0135] In the vacuum pump P, the shaft seals 21a, 21b are formed by a double O-ring structure,
in order to prevent air leakage, as far as possible, and hence it is possible satisfactorily
to guarantee the pressure differential state between the negative pressure (30 torr
or less) inside the upper chamber 15a of the cylinder 15 and the external atmosphere
(760 torr). Moreover, by adopting a dual structure in this way, it is possible to
prevent foreign material which is liable to adhere to and infiltrate inside the seal
section when the supporting shaft 17 is operated. Furthermore, the shaft seals 22a,
22b are formed by a double O-ring structure in order to prevent air leakage as far
as possible, and hence they provide a sufficient guarantee of a differential pressure
state between the negative pressure (30 torr or less) of the upper chamber 15a of
the cylinder 15 and the pressure of the lower chamber 15b (760 torr), generated when
the piston 28 performs reciprocal movement.
[0136] Now, a concrete installation procedure for an air conditioner is described. The indoor
unit-is connected via connection pipes 9 and 10 to the liquid-side two-way valve 7
and gas-side three-way valve 8 of the outdoor unit. The vacuum pump P is connected
to the low pressure port 12b of the gauge manifold 12 and the pressure-resistant hose
11 leading from the central port 12 a is attached to the service port section 8b of
the gas-side three-way valve 8, thereby achieving a state in which the pressure-resistant
hose 11 is communicated with the indoor unit and the interior of the connection pipes
9, 10. Moreover, the interior of the pressure-resistant hose 13 is in the communication
state by opening the low pressure side handle 12c of the gauge manifold 12.
[0137] Next, the operator causes the handle 18 of the vacuum pump to perform reciprocal
movement, as described previously, and by reading the number of strokes of reciprocal
movement from the display 183, he or she is able to estimate when the interior of
the indoor unit and the connection pipes 9, 10 has reaches a sufficient negative pressure
state. Moreover, the sufficient negative pressure state is finally confirmed by the
operator from the reading on the vacuum gauge 12d on the gauge manifold 12. Immediately
after that, the low pressure side handle 12c of the gauge manifold 12 is closed off,
and the after waiting for a short while, it is checked that there is not change in
the reading on the vacuum gauge 12d. Here, if there is a change in the reading, then
this means that there is an air leak occurring at some point of the coupling of the
connection pipes 9, 10.
[0138] Next, the screw section 7a of the liquid-side two-way valve 7 is slightly loosened,
and refrigerant gas from the outdoor unit is introduced, thereby setting the interior
of the connection pipes 9, 10 and the indoor unit to a slightly positive pressure
state (approximately 0.2 kgf/cm
2). Thereupon, the pressure-resistant hose 11 is detached from the service port section
8b, and the screw section 7a of the liquid-side two-way valve 7 is rotated by a further
quarter turn to apply a more pressurized state (approximately 3 - 6 kgf/cm
3) in order to recheck for leaking in the connection pipe sections. Finally, the screw
section 7a of the liquid-side two-way valve 7 is opened fully, and the screw, section
8a of the gas-side three-way valve 8 is also opened fully, thereby completing the
tasks for installation of an air conditioner.
[0139] In the present embodiment, the internal volume of the piping of the indoor unit including
the indoor heat exchanger 6, and the connection pipes 9, 10, was 1.5 litres. In the
vacuum pump P, the internal volume of the upper chamber when the piston is at the
bottom dead center was 150 ml, and the total volume from the cylinder outlet formed
when the piston is at the top dead center, to the two non-return valves on the intake
port side and the exhaust port side, was 1.5 ml. These figures are taken to include
the port flow path space arising in the cylinder wall. The cylinder internal dead
space formed when the piston is at the top dead center was 2 ml. Taking via to be
the total volume of the internal volume of the upper chamber formed when the piston
is at the bottom dead center, and the internal space from the cylinder outlet to the
intake port non-return valve and the exhaust port non-return valve, and taking V1b
to be the total volume of the cylinder internal dead space formed when the piston
is at the top dead center, and the internal space from the cylinder outlet to the
intake port non-return valve and the exhaust port non-return valve, then the relationship
between Via and V1b is V1a/V1b = 44. Fig. 35 is a concrete illustration of the V1b
region comprising the cylinder internal dead space and the total spatial volume from
the cylinder outlet to the intake port non-return valve and the exhaust port non-return
valve when the piston is at the top dead center.
[0140] Using this construction and following the work procedure described above, it was
possible to achieve a pressure of 30 torr with this vacuum pump, by performing 40
strokes of reciprocal movement of the handle. Fig. 11 illustrates the progress of
the negative pressure state in this case, in the form of a relationship between the
number of strokes and the internal pressure. The progress of the negative pressure
was checked up to 50 strokes, but the attained pressure level reached a state of equilibrium
at 40 strokes and does not progress any further thereafter.
[0141] Consequently, it can be seen that when a vacuum pump according to the present embodiment
is applied to a system having an internal volume of 1.5 litres, then 40 strokes is
the general standard for the attained vacuum level. To obtain an accurate figure,
the vacuum level was monitored separately using a digital pressure sensor. Reliability
testing was carried out for 5000 hours in an air conditioner using R410A as the refrigerant
and an ester oil as the cooling unit oil, by setting the output temperature of the
compressor to an overload condition of 115°C, and setting both the indoor unit and
the outdoor unit to high-temperature cooling conditions of 40°C. No particular irregularities
were observed as a result of this testing.
(Tenth embodiment)
[0142] Fig. 36 is a schematic diagram giving a detailed illustration of the construction
of the vacuum pump and the connection path of the pressure-resistant hoses in the
present embodiment. Since the present embodiment uses a vacuum pump that is virtually
the same as that in the ninth embodiment, detailed description thereof is omitted
here and the description will focus on the different parts. In the vacuum pump P,
a one-touch pipe joint 26 was detachably attached to a connecting section to the non-return
valve 31a of the intake port 31 provided on the cylinder 15, via the pressure-resistant
hose 25. Furthermore, a screw-fitting sealing cap 39 was provided for the open port
37 as a member for sealing of the air intake or exhaust actions.
[0143] Fig. 19 is a sectional view of the construction of the aforementioned one-touch pipe
joint 26. The more specific aspects of the construction are described below. A release
bush 341 is provided around the pressure-resistant hose, and the release bush 341
is fixed by providing a guide 343 and collet 344 on the main body 342 of the tubular
pipe joint. A tubular chuck 345 is disposed between the release bush 341 and collet
344, and the chuck 345 is caused to bite on the outer circumference of the pressure-resistant
hose, thereby preventing the pressure-resistant hose from detaching, by pressing the
front end of the chuck 345 in the direction of the pressure-resistant hose by means
of a CR rubber lip seal 346.
[0144] Furthermore, since the biting pressure of the front end of the chuck 345 can be released
by pushing the release 341 towards the inner side along the pressure-resistant hose
13, the pressure-resistant hose 13 can be detached readily. Provided that the lip
seal 346 is functioning sufficiently, then it is possible to prevent air leakage.
[0145] Next, a concrete installation procedure for an air conditioner according to the present
invention is described. Firstly, a pressure-resistant hose 13 is connected to the
one-touch pipe joint 26 arranged on the intake port 31 of the vacuum pump P. The sealing
cap 39 screwed onto the open port 37 is removed, the handle 18 is pulled upwards to
reposition the piston 28 in an approximately central position in the cylinder 15,
and the sealing cap 39 is then screwed into the open port 37, thereby sealing the
intake and exhaust flow path. The pressure-resistant hose 13 is also coupled to the
low pressure port 12b of a gauge manifold 12, and a pressure-resistant hose 11 is
attached to the service port section 8b. Therefore, the pressure-resistant hose 11
is in a state of connection with the interior of the indoor unit and the connection,
pipes 9, 10. Moreover, the pressure-resistant hose 13 is also connected thereto by
opening the low pressure side handle 12c of the gauge manifold 12.
[0146] Next, the operating mechanism of the vacuum pump is described. Firstly, when the
handle 18 is pushed in the direction of arrow b (towards the bottom dead center),
the air inside the indoor unit and the connection pipes 9, 10 is drawn in from the
service port section 8b, via the pressure-resistant hose 11, the gauge manifold 12
and the pressure-resistant hose 13, and into the upper chamber 15a inside the cylinder
15, by means of the non-return valve 31a of the intake port 31. Conversely, the air
in the lower chamber 15b is in a sealed space, and is therefore compressed, which
means that when the bottom dead center is reached and the force on the handle 18 is
relaxed, the piston 28 returns of its own accord, without applying virtually any external
force, and moves upwards in the direction of arrow b, due to the joint effect of the
reactive action of the compressed air and the pressure differential between the upper
chamber 15a and the lower chamber 15b. The air in the upper chamber 15a is exhausted
into the atmosphere via the non-return valve 30a of the exhaust port 30. When the
handle 18 is pressed down again, it is possible to advance the interior of the indoor
unit and the connection pipes 9, 10 in the negative pressure direction.
[0147] In this way, a vacuum pump can be achieved having a pressure reducing mechanism in
the b direction when reciprocal movement of the handle 18 of the vacuum pump is performed.
By reading the number of stroke movements of the piston 28 from the display 183, the
operator is able to estimate and determine when the interior of the indoor unit and
the connection pipes 9, 10 has reached a sufficient negative pressure state. Moreover,
the operator can also confirm the sufficient negative pressure state from the reading
of the vacuum gauge 12d on the gauge manifold 12. Immediately thereupon, the low pressure
side handle 12c of the gauge manifold 12 is closed, and after waiting for a short
while, it is checked that there has been no change in the reading of the vacuum gauge
12d. Here, if there has been change in the reading, then this means that an air leak
is occurring at some point in the connection pipe sections.
[0148] Next, the screw section 7a of the liquid-side two-way valve 7 is slightly loosened,
and refrigerant gas from the outdoor unit is introduced, thereby setting the interior
of the connection pipes 9, 10 and the indoor unit to a slightly positive pressurestate
(approximately 0.2 kgf/cm
2). Thereupon, the pressure-resistant hose 11 is detached from the service port section
8b, and the screw section 7a of the liquid-side two-way valve 7 is rotated by a further
quarter turn to apply a more pressurized state (approximately 3 - 6 kgf/cm
2) in order to recheck for leaking in the connection pipe sections. Finally, the screw
section 7a of the liquid-side two-way valve 7 is opened fully, and the screw section
8a of the gas-side three-way valve 8 is also opened fully, thereby completing the
installation tasks for installation of an air conditioner.
[0149] Finally, when storing away the vacuum pump P, the sealing cap 39 screwed onto the
open port 37 is again removed, the handle 18 is pressed downwards to drive out the
air in the lower chamber 15b, and the sealing cap 39 is then screwed on and the pressure-resistant
hose 13 is removed from the one-touch pipe joint 26. Thereby, it is possible to compactify
the vacuum pump to achieve good portability.
[0150] In the present embodiment, the sealing cap 39 was provided for the open port 37 when
the piston 28 had been repositioned in an approximately central position in the cylinder
15, but the position to which the piston 28 should be moved in the cylinder 15 should
be determined in the following manner. Since the level to which air can be compressed
by manual force is approximately 10 kg/cm
2 at maximum, then the total internal volume of the cylinder internal dead space formed
when the piston is at the bottom dead center, and the volume from the cylinder outlet
to the open port sealed by the sealing cap, should be approximately 10 - 20 ml.
[0151] In the present embodiment, a one-touch pipe joint 26 as illustrated in Fig. 19 was
used as a connecting section whereby the pressure-resistant hose can be readily attached
to and detached from the vacuum pump, but the attachable and detachable connecting
section which can be used in the present invention is not limited to this. In addition
to this, it is also possible to use a tube coupler, or the like, which does not comprise
a self-sealing mechanism.
(Eleventh embodiment)
[0152] The present embodiment is an installation method, in which the air inside the indoor
unit piping and the connection pipes 9, 10 of an air conditioner as illustrated in
Fig. 33 is substituted with carbon dioxide gas, using a carbon dioxide gas pump, whereupon
the work procedure according to the ninth embodiment is followed. Compared to the
installation method implemented in the ninth embodiment, the oxygen inside the indoor
unit piping and the connection pipes 9, 10 can be further reduced, thus increasing
accuracy, and a vacuum pump P having the same construction as that in the ninth embodiment
was used. The internal volume of the piping of the indoor unit, including the indoor
heat exchanger 6, and the connection pipes 9, 10, was 1.5 litres.
[0153] In the vacuum pump, the internal volume of the upper chamber formed when the piston
is at the bottom dead center was 80 ml, and the total internal space from the cylinder
outlet formed when the piston is at the top dead center to the two non-return valves
on the intake port side and the exhaust port side was 1.5 ml. These figures are taken
to include the port flow path space arising in the main wall of the cylinder. The
cylinder internal dead space from when the piston is at the top dead center was 2
ml. Taking V1a to be the total volume of the internal volume of the upper chamber
formed when the piston is at the bottom dead center, and the internal space from the
cylinder outlet to the intake port non-return valve and the exhaust port non-return
valve, and taking V1b to be the total volume of the cylinder internal dead space formed
when the piston is at the top dead center, and the internal space from the cylinder
outlet to the intake port non-return valve and the exhaust port non-return valve,
then the relationship between V1a and V1b is V1a/V1b = 23.
[0154] Firstly, the air inside the piping of the indoor unit and the connection pipes 9,
10 was substituted with carbon dioxide gas, using a carbon dioxide pump. More specifically,
the outlet of a carbon dioxide gas pump is connected to the service port 8b of a liquid
side gas three-way valve 8, a flare nut of the liquid-side two-way valve 7 (not illustrated)
is loosened to connect the connection pipe 9 to the atmosphere, and when the air inside
the connection pipe 10, the internal pipes of the indoor unit and the connection pipe
9 has been exhausted into the atmosphere and substituted by carbon dioxide gas, the
flare nut of the liquid-side two-way valve 7 is closed, and the carbon dioxide gas
pump is detached from the service port 8b. Thereupon, by using the vacuum pump in
accordance with the work procedure according to the ninth embodiment, it was possible
to achieve 60 torr. Reliability testing was carried out for 5000 hours in an air conditioner
using R410A as the refrigerant and an ester oil as the cooling unit oil, by setting
the output temperature of the compressor to an overload condition of 115°C, and setting
both the indoor unit and the outdoor unit to high-temperature cooling conditions of
40°C. No particular irregularities were observed as a result of this testing.
[0155] In the present embodiment, the interior of the indoor unit piping and the connection
pipes was substituted with carbon dioxide gas, but the specific gas which can be used
in the present invention is not limited to this. In addition, it is possible to use
any gas which is not liable to affect the reliability of the refrigerating cycle.
More specifically, besides carbon dioxide gas, it would be possible to-use gases such
as nitrogen, methane, ethane, propane, isopropane, argon, or the like.
[0156] In the pressure reducing mechanism in a vacuum pump according to the present invention
as described above, it is possible to generate pressure reduction by a pressure reducing
mechanism inside the cylinder, only when the piston is moved in the downward direction,
and the cylinder internal dead space formed when the piston is at the top dead center,
and the spatial volume from the cylinder outlet to the intake port non-return valve
and the exhaust port non-return valve, form a dead space. The cylinder internal dead
space comprises the small gap formed when the piston meets the plane of the bottom
dead center of the cylinder, and the intake port and exhaust port flow paths formed
inside the cylinder wall. Therefore, with regard to the attained vacuum level, the
relationship between V1a, which is the total volume of the internal volume of the
upper chamber formed when the piston is at the bottom dead center, and the volume
of the internal space from the cylinder outlet to-the intake port non-return valve
and the exhaust port non-return valve, and V1b which is the total of the cylinder
internal dead space formed when the piston is at the top dead center, and the volume
of the internal space from the cylinder outlet to the intake port non-return valve
and the exhaust port non-return valve, is very important. If a design is adopted whereby
the relationship between V1a and V1b is V1a/V1b ≥ 40, and if the leakage at the non-return
valves is controlled to some extent, then it was found that it is possible to achieve
a pressure of 30 torr or less, satisfactorily, by performing reciprocal movement of
the handle of the vacuum pump. If the relationship V1a/V1b is top large, then although
there will be no impediment to the level of vacuum attained, the vacuum pump will
be become bulky and heavy and portability of the device will be impaired. Moreover,
the operation for performing reciprocal movement of the handle will be impaired.
[0157] It can be seen that the number of strokes of the vacuum pump required in the installation
of an air conditioner according to the present invention is determined by the relationship
between the internal volume of the piping of the indoor unit and the connection pipes,
and the internal volume of the cylinder space. If the internal volume of the indoor
unit piping and the connection pipes is 1.5 litres, and the internal volume of the
cylinder space is 150 ml, then a state of equilibrium is reached after performing
approximately 40 strokes of reciprocal movement, and if the internal volume of the
indoor unit and the connection pipes is 2.5 litres, and the internal volume of the
cylinder space is 250 ml, then a state of equilibrium is reached after performing
approximately 70 strokes of reciprocal movement. Therefore, by establishing these
relationships in a database, it is possible for an operator to estimate and deduce
the general state of the vacuum level attained, by controlling the number of strokes
of the vacuum pump by means of the sensor according to the present invention.
[0158] The piston shaft seal which can be used in the present invention was taken to be
a seal having a dual O-ring structure, similarly to the seals used for the supporting
shaft, and since the open port of the lower chamber is sealed off to form a sealed
space, and the air is compressed when the piston is moved downwards, then a large
pressure differential is generated between the lower chamber and the upper chamber.
In this case, a dual O-ring structure is superior in order to sufficiently control
air leakage from the lower chamber to the upper chamber.
[0159] In the respective embodiments described above, a drier was provided inside the main
body of the outdoor unit. In the vacuum pump according to the present invention, it
is difficult to exhaust moisture present inside the indoor unit and the connection
pipes, in comparison to an electric vacuum pump. Therefore, long term reliability
can be guaranteed more readily in the case of air conditioners which are equipped
with a drier in the refrigerating cycle.