Background of the Invention:
[0001] This invention relates to a refrigerant recovering system.
[0002] A refrigerant, such as a fluorocarbon refrigerant, is commonly employed in an air
conditioner of an automobile or a refrigerator.
[0003] A refrigeration system will operate most efficiently when the refrigerant is made
pure and relatively free of pollutants, for example, oil, air and water. But, a used
refrigerant becomes impure by pollutants.
[0004] Therefore, it is necessary to periodically remove and recharge the refrigerant within
the refrigerant system.
[0005] Various refrigerant processing and charging system are already known. In the Miyata
et al article, a citation is made as regards refrigerant charging system of the type
disclosed in Japanese Patent Prepublication (
Kookai) No. 251767 of 1988.
[0006] Such a refrigerant recovering system comprises a liquefying unit which sucks an original
refrigerant from an external freezing circuit or refrigeration circuit which is employed
in, for example, an air conditioning system.
[0007] When the original refrigerant is sucked from the external freezing circuit by a suction
unit, amounts of the original refrigerant in the external freezing circuit gradually
decreases.
[0008] According to decreasing the amounts of the original refrigerant, inner temperature
of the external freezing circuit gradually decreases by an evaporation of the original
refrigerant in the external circuit.
[0009] As a result, inner pressure of the external freezing circuit becomes negative pressure
in comparison with atomospheric pressure. This negative pressure causes the external
freezing circuit to be invaded by atmosphere, therein.
Summary of the Invention:
[0010] It is therefore an object of the present invention to provide a refrigerant recovering
system for recovering an original refrigerant from an external freezing circuit et
al without invasion of atmosphere into the external freezing circuit.
[0011] It is another object of this invention to provide a system of the type described,
which can prevent from decrease of inner pressure of the external freezing circuit
while charging the original refrigerant.
[0012] Other objects of this invention will become clear as the description proceeds.
[0013] In accordance with this invention, there is provided a refrigerant recovering system
for use in recovering an original refrigerant from a refrigeration circuit. The refrigerant
recovering system comprises a suction unit for sucking the original refrigerant, a
producing unit coupled to the refrigeration circuit and responsive to inner pressure
of the original refrigerant for producing a pressure signal, a supplying unit coupled
to the refrigeration circuit and the suction unit and responsive to the pressure signal
for supplying the original refrigerant from the refrigeration circuit to said suction
unit.
Brief Description of the Drawing:
[0014]
Fig. 1 is a block diagram of a refrigerant recovering system according to an embodiment
of this invention.
Description of the Preferred Embodiment:
[0015] A refrigerant recovering unit according to an embodiment of this invention is connected
to an air conditioning system of an automobile.
[0016] The air conditioning system uses a fluorocarbon refrigerant as an original refrigerant
in a freezing circuit (not shown).
[0017] Referring to Fig. 1, the refrigerant recovering unit comprises an inlet electromagnetic
valve 10 on a conducting pipe 12 which is coupled to the external freezing circuit.
The original refrigerant flows as a liquid phase flow and gaseous flow through the
conducting pipe 12.
[0018] For controlling inner pressure of the external freezing circuit, a pressure sensor
11 is connected to the external freezing circuit. The pressure sensor 11 is for judging
whether or not the inner pressure is negative in comparison with atmospheric presure
to produce an internal signal when the inner pressure is negative. The internal signal
is sent to the electromagnetic valve 10 through a wire 11a. Responsive to the internal
signal, the electromagnetic valve 10 is automatically driven to inhibit passage of
the original refrigerant in the conducting pipe 12.
[0019] When the inlet electromagnetic valve 10 is opened for introducing the original refrigerant
from the freezing circuit, the original refrigerant is sucked to a first filter dryer
13 by virtue of a compressor 18 which will later be described. The inlet electromagnetic
valve 11 can be disconnected from the freezing circuit. The first filter dryer 13
is for removing an impurity, moisture, and acid content from the original refrigerant
in the manner known in the art.
[0020] An accumulator 14 is connected to the first filter dryer 13 for accumulating the
original refrigerant. The liquid phase flow is accumulated in a bottom part of the
accumulator 14, and the gaseous phase flow thereon is supplied to a first oil intercepter
15. The first oil intercepter 15 is to intercept an oil element of the original refrigerant.
The intercepted oil element is accumulated in an oil tank 17 through an oil valve
16.
[0021] The original refrigerant is supplied to the compressor 18 from the first oil intercepter
15. In this event, the original refrigerant is of gaseous phase.
[0022] The gaseous original refrigerant is compressed in the compressor 18 and is supplied
as a compressed refrigerant to a condenser 20 through a second oil intercepter 19.
The intercepted oil element is accumulated in another oil tank (not shown). In the
condenser 20, the compressed refrigerant is cooled to thereby be condensed as a condensed
refrigerant. The condensed refrigerant is supplied to a second filter dryer 21 which
is for removing an impurity, moisture, and acid content from the condensed refrigerant.
[0023] After that, the condensed refrigerant is supplied to a separation vessel 22 and is
separated into a gaseous phase refrigerant component and a liquid phase refrigerant
component in the separation vessel 22.
[0024] The separation vessel 22 comprises an upper part and a bottom part defining an upper
space and a bottom space, respectively. The upper space and the bottom space is contiguous
each other to form a hollow space in the separation vessel 22. As well known in the
art, the gaseous phase refrigerant component has superior purity in comparison with
the liquid phase refrigerant component.
[0025] A combination of the compressor 18, the second oil intercepter 19, the condenser
20, the second filter dryer 21 and, the separation vessel 22 is referred to as a separating
arrangement. A pipe 12 is for connecting between the inlet electromagnetic valve 11
and the separation vessel 22.
[0026] The separation vessel 22 has a first outlet port 22a at an upper portion thereof
and a second outlet port 22b at a bottom portion thereof. The first outlet port 22a
is connected to a liquefication vessel 24a through a first supplyingn pipe 12a to
communicate with a thermal space which is defined by the liquefication vessel 24a.
Therefore, the gaseous phase refrigerant component is sent as an object refrigerant
from the separation vessel 22 to the liquefication vessel 24b. On the other hand,
the second outlet port 22b is connected to an evaporator 24b through an automatic
expansion valve 23 and a second supplying pipe 12b. Therefore, the liquid phase refrigerant
component is sent as a liquid refrigerant from the separation vessel 22 to the evaporator
24b and is evaporated in the evaporator 24b to carry out cooling of a surrounding
area of the evaporator 24b in the manner known in the art.
[0027] The evaporator 24b is thermally coupled to the thermal space of the liquefication
vessel 24a. In this embodiment, the evaporator 24b is contained in the liquefication
vessel 24a. As a result, the gaseous phase refrigerant component is cooled in the
liquefication vessel 24a by evaporation of the liquid refrigerant, namely, the liquid
phase refrigerant component in the evaporator 24b. In other words, heat exchange is
carried out between the gaseous and the liquid phase refrigerant components. Therefore,
the evaporator 24b may be referred to as a liquefying arrangement.
[0028] After being evaporated in the evaporator 24b, the liquid refrigerant is returned
to the compressor 18 through a returning pipe 12c.
[0029] A temperature detecting unit 25 is thermally coupled to the returning pipe 12c. The
temperature detecting unit 25 is for detecting temperature of the liquid refrigerant
at vicinity of the liquefication vessel 24a to produce a tempeature signal which is
representative of the temperature signal which is representative of the temperature.
Responsive to the temperature signal, the automatic expansion valve 23 is automatically
driven to adjust flow amount of the liquid phase refrigerant component.
[0030] The liquefied object refrigerant is collected at a lower portion of the thermal space
of the liquefication vessel 24a. A storage container 26 is placed under the liquefication
vessel 24a and is connected to the thermal space through a sending pipe 27. Therefore,
the liquefied object refrigerant drips from the liquefication vessel 24a towards the
storage container 26 through the sending pipe 27 by gravitational force thereof. As
a result, the liquefied object refrigerant is charged in the storage container 26.
It is a matter of course that the modified refrigerant has a relatively higher purity
in the storage container 26.
[0031] When the thermal space is not enough of quantity of the liquefied object refrigerant,
the liquefied object refrigerant is prevented from charging thereof towards the storage
container 26.
[0032] For controlling quantity of liquid of the thermal space, a liquid level sensor 28
is connected to the liquefication vessel 24a. The liquid level sensor 28 is for detecting
a predetermined liquid level to produce a condition signal. The condition signal is
sent to an electromagnetic valve 29. The electromagnetic valve 29 is coupled to the
sending pipe 27. Responsive to the condition signal, the electromagnetic valve 29
is automatically driven to adjust the movement of the liquefied object refrigerant
through the sending pipe 27. A combination of the sending pipe 27, the liquid level
sensor 28, and the electromagnetic valve 29 is referred to as a control arrangement.
In this event, it is preferable that the condition signal responsive to the predetermined
liquid level is produced until the evaporator 24b is made thoroughly wet by the liquefied
object refrigerant in the liquefication vessel 24b because of an effectiveness of
the heat exchange. When the detected liquid level is lowered than the predetermined
liquid level, the electromagnetic valve 29 is driven in response to the condition
signal to stop the dripping of the liquefied object refrigerant to the storage container
26.
[0033] When the detected liquid level is higher than the predetermined level, the electromagnetic
valve 29 is driven in response to the condition signal to open the sending pipe 27.
So that, the liquefied object refrigerant flows into the storage container 26. Preferably,
a breathing pipe 30 is disposed between the liquefication vessel 24a and the storage
container 26 for breathing a residual gas of the refrigerant in the storage container
26 because of smooth flow of the liquefied object refrigerant. Therefore, the effectiveness
of the heat exchange is increased in the liquefying arrangement.
[0034] The object refrigerant can be smoothly charged into the storage container 26 by a
repeat of operation which is described before.
[0035] While the present invention has thus far been described in connection with the embodiment
thereof, it will readily be possible for those skilled in the art to put this invention
into practice in various other manners.
1. A refrigerant recovering system for use in recovering an original refrigerant from
a refrigeration circuit, comprising suction means for sucking said original refrigerant,
wherein the improvement comprising:
producing means coupled to said refrigeration circuit and responsive to inner pressure
of said refrigerant circuit for producing a pressure signal;
supplying means coupled to said refrigeration circuit and said suction means and responsive
to said pressure signal for supplying said original refrigerant from said refrigeration
circuit to said suction means.
2. A refrigerant recovering system as claimed in Claim 1, wherein said producing means
comprises:
judgement means coupled to said refrigerant circuit for judging whether or not said
inner pressure is negative in comparison with atmospheric pressure to produce an internal
signal when said inner pressure is negative;
sending means coupled to said judgement means for sending said internal signal as
said pressure signal to said supplying means.
3. A refrigerant recovering system as claimed in Claim 2, wherein said supplying means
comprises:
conducting means coupled to said refrigerant circuit and said suction means for conducting
said original refrigerant into said suction means;
inhibit means coupled to said conducting means responsive to said pressure signal
for inhibiting passage of said original refrigerant into said suction means.