[0001] The present invention relates to a piston-driven positive displacement pump, having
a single piston or a plurality thereof.
[0002] In particular, the present invention relates to high-pressure pumps such as those
which are commonly used in the industrial cleaning sector or other sectors of industry
and agriculture.
[0003] As is known, a high-pressure pump generally comprises a plurality of pistons, each
of which is slidably housed internally of a respective cylinder such as to define
therewith a variable-volume pumping chamber, which communicates with an aspirating
conduit and a delivery conduit via respective valves.
[0004] The cylinders and aspirating and delivery conduits are normally realized in a single
monolithic body made of a metal material, for example brass, which is commonly known
as the head.
[0005] The head is fixed to a casing in which a crank shaft and a plurality of con rods
are housed, each of which is destined to connect the crank shaft with a respective
piston, such as to transform the rotary motion of the former into an alternating motion
of the latter.
[0006] To prevent malfunctioning, conserving the integrity of the mechanical components
and reduce the energetic consumption associated to the functioning of the high-pressure
pumps, it is essential that the above-delineated mechanism is constantly lubricated.
[0007] The lubrication is generally obtained with an agitated oil-bath system, i.e. by predisposing,
in the internal volume of the casing, a predetermined quantity of lubricating oil
which strikes the support bearings of the crank shaft and which is agitated by the
movement of the crank shaft and the con rods, in such a way as also to reach the connecting
joints between the crank shaft and the con rods and the connecting joints between
the con rods and the pistons.
[0008] A drawback of this solution derives however from the fact that the effectiveness
of the lubrication depends on some chemical-physical characteristics of the lubricating
oil, such as the viscosity, which can strongly depend on the temperature which the
lubricating oil reaches during the functioning of the high-pressure pump.
[0009] For this reason, if the temperature of the lubricating oil is too high or too low
with respect to an optimal design value, it can happen that the lubrication of a high-pressure
pump is defective, causing an increase in wear and energy consumption.
[0010] A further drawback consists in the fact that if the temperature of the lubricating
oil reaches extremely high values, safety problems can arise, or in any case a permanent
deterioration of the chemical-physical characteristics of the lubricating oil can
ensue.
[0011] At present the temperature of the lubricating oil is not controlled by the users
during functioning of the pump, so that the risk of reaching critical conditions or
in any case causing malfunctioning is effectively rather high.
[0012] An aim of the present invention is to obviate the mentioned drawbacks, by providing
a solution that enables users to intervene in good time in a case in which the temperature
of the lubricating oil exhibits anomalous values.
[0013] A further aim of the present invention is to attain the above-mentioned objective
with a solution that is simple, rational and relatively inexpensive. These and other
aims are attained by the characteristics of the invention as recited in independent
claim 1. The dependent claims delineate preferred and/or particularly advantageous
aspects of the invention.
[0014] In particular, in an embodiment of the present invention a pump is provided comprising
a head, in which at least a cylinder is afforded in which a piston is slidably housed,
and a casing fixed to the head, which defines an internal volume in which are housed
a crankshaft and at least a con rod able to connect the crankshaft with the piston,
such as to be able to transform a rotary motion of the crankshaft into an alternating
motion of the piston, signalling means of the temperature of the lubricating oil contained
in the internal volume of the casing being applied to the casing.
[0015] Thanks to this solution, the signaling means enable the users to keep the temperature
of the lubricating oil under control during the functioning of the high-pressure pump,
placing the users in a condition to intervene in good time should anomalous values
be encountered.
[0016] By "signalling means" is generally intended any device able to signal, i.e. transmit
to the users, a direct or indirect measurement of the temperature of the lubricating
oil.
[0017] In a general sense, the signaling means could therefore be connected to a separate
sensor able to perform the measurement of the temperature of the lubricating oil.
[0018] However, in a preferred embodiment of the present invention the signalling means
include, as a thermometer, also the measuring means of the temperature.
[0019] By applying a thermometer to the casing an indirect measurement of the temperature
of the lubricating oil is obtained, with a technically very simple and easily-applicable
solution.
[0020] In a preferred aspect of the invention this thermometer can contain a thermochromic
substance, which is able to change colour on the basis of the temperature to which
it is heated.
[0021] The thermometer can be for example a liquid crystal thermometer (LCT) which can be
applied to the casing with an adhesive.
[0022] In a further aspect of the present invention, the pump can also comprise signalling
means of the level of the lubricating oil contained in the internal volume of the
casing.
[0023] This aspect of the invention is advantageous as the effectiveness of the lubrication
system also depends on the fact that the level of the lubricating oil is comprised
between a minimum design value and a maximum design value.
[0024] At present the level of the lubricating oil is controlled during periodical maintenance
interventions of the high-pressure pump, for example by means of a graduated rod which
is inserted into the casing through the filler mouth of the lubricating oil.
[0025] This control procedure is however rather awkward and laborious, and the users tend
to leave too much time between checks of the level of the lubricating oil, with the
consequence that the high-pressure pump can sometimes be functioning in non-optimal
lubricating conditions, increasing wear and energy consumption.
[0026] Thanks to the above-mentioned signalling means applied to the casing, the users can
keep the lubricating oil level under control in a very much simpler and more immediate
way.
[0027] In this case too, by "signalling means" in generally meant any device able to signal,
i.e. transmit to the users a direct or indirect measurement of the level of the lubricating
oil internally of the pump casing.
[0028] An embodiment of the present invention includes for example the signalling means
of the level simply comprising a transparent body which can enable a direct vision
of the level of the oil contained in the internal volume of the casing.
[0029] In this way the users are able to control the level of the lubricating oil visually
and rapidly, with a solution that is extremely simple and economical.
[0030] A further advantage of this solution consists in the fact that the users can directly
view and therefore control also the colour and/or opacity of the lubricating oil,
for example in order to see whether the oil is excessively dirty or worn or whether
it has been contaminated with infiltrations of water during the functioning of the
pump.
[0031] In an aspect of this embodiment, the transparent body can be faced to the opaque
contrast body (i.e. a non-transparent body), with which it defines a gap that is in
hydraulic communication with the internal volume of the casing. This solution has
the advantage of improving the vision of the level and qualitative characteristics
of the lubricating oil, as the contrast body can reflect a part of the external light,
enabling a better illumination of the slim layer of lubricating oil which is in the
gap between the contrast body and the transparent body.
[0032] In a preferred embodiment of the present invention, the signalling means of the temperature
and/or the signalling means of the level can both be applied to a removable cover
of the casing.
[0033] Thanks to this solution, the cover can be realised and assembled separately with
respect to the casing, simply and economically, and be fixed to the casing later,
during the step of assembling the high-pressure pump.
[0034] In an aspect of this embodiment, the cover can be aligned with the rotation axis
of the crankshaft, for example it can be the cover which supports one of the support
bearings for the crankshaft.
[0035] Thanks to this solution, the signalling means are in an optimum position for enabling
the users to control the level and the temperature of the lubricating oil.
[0036] Further characteristics and advantages of the invention will emerge from a reading
of the following description, provided by way of non-limiting example, with the aid
of the figures illustrated in the accompanying tables of drawings.
Figure 1 is a perspective view of a high-pressure piston pump in an embodiment of
the present invention.
Figure 2 is a lateral view of the pump of figure 1.
Figure 3 is section III-III of figure 2.
Figure 4 is a larger-scale detail of figure 1.
Figure 5 is a larger-scale detail of figure 3.
[0037] As illustrated in figure 3, the high-pressure pump 100 can comprise a plurality of
pistons 105 arranged in line and with parallel axes, each of which is slidably inserted
internally of a respective cylinder (not visible) with which they define a pumping
chamber.
[0038] The high-pressure pump cylinders 100 are realized internally of a head 110, which
can be manufactured as a monolithic body made of a metal material, typically brass.
[0039] As illustrated in figure 2, also realized in the head 100 are an aspirating manifold
115 for the fluid to be pumped (for example water) and a delivery manifold 120 for
the pressurized fluid, which are in communication with each of the pumping chambers
respective through an aspirating valve and a delivery valve (not visible). The aspirating
and delivery valves are singly housed internally of respective seating 125 and 130
(figure 1), which are fashioned in the head 110 and are sealedly closed by appropriate
threaded caps 135 and 140.
[0040] The head 110 is fixed to a metal casing 145, for example steel or cast iron, internally
of which a crankshaft 150 is rotatably housed, having a rotation axis perpendicular
to the piston axes 105 (figure 3). This crankshaft 150 is profiled in such a way as
to define a number of lengths of crankshaft that is equal to the number of pistons
105, and each of these lengths of crankshaft is connected to a respective piston 105
by means of a con rod 155 which is also contained internally of the casing 145. In
this way, the rotation of the crankshaft 150 is transformed by each con rod 155 into
an alternating motion of the respective piston 105, thus causing pumping of the fluid
from the aspirating manifold 115 to the delivery manifold 120.
[0041] The crankshaft 150 is supported internally of the casing 145 by a pair of bearings
160 and 165, each of which is axially housed and blocked in a seating afforded in
a respective metal cover 170 and 175. The covers 170 and 175 are fixed on opposite
flanks of the casing 145, substantially aligned to one another and to the crankshaft
150. In particular, each cover 170 and 175 is fixed to the casing 145 by means of
demountable fixing means, in the example by a series of screws 180, such as to be
removable and separated from the casing 145 in case of need. The end of the crankshaft
150 located at the cover 170 terminates and is contained internally of the casing
145, while the opposite end projects externally of the cover 175, such as to define
a connecting spur by means of which the crankshaft 150 can be connected with an activating
motor, possibly through a suitable transmission and reduction system.
[0042] The internal volume of the casing 145 further contains a predetermined quantity of
lubricating oil (not visible) which is destined to lubricate, by shaking circulation,
the entire mechanism of the high-pressure pump 100 and in particular the bearings
160 and 165, the joints between the crankshaft 150 and the con rods 155, and the joints
between the con rods 155 and the respective pistons 105. This lubricating oil can
be poured internally of the casing 145 by means of an inlet mouth 185 (see figure
1) and can possibly be discharged via an outlet mouth 190 (figure 2), both of which
are normally closed by a respective removable closing cap.
[0043] As illustrated in figures 4 and 5, the cover 170 exhibits a projecting portion 195
having a generally cylindrical shape, which is aligned and substantially coaxial with
the crankshaft 150. This projecting portion 195 terminates with an end wall 200 that
is substantially flat, to which are associated both a device 205 for signaling the
level of the lubricating oil internal of the casing 145 and a thermometer 210 able
to measure and signal the temperature of the lubricating oil.
[0044] The thermometer 210 can be one containing a thermochromic substance, which changes
colour on the basis of the temperatures to which it is heated. For example, the thermometer
210 illustrated in the figures is a liquid crystal adhesive thermometer, which is
fixed on the bottom of a lowering 215 having a substantially semicircular shape which
occupies about a half of the external surface of the end wall 200. In this way, the
thermometer 210 measures the temperature of the cover 170, which however represents
an indirect measurement of the temperature of the lubricating oil.
[0045] A liquid crystal thermometer can generally comprise two layers of flexible and impermeable
material, of which a lower layer applicable on the surfaces the temperatures of which
are to be measured, and an upper layer that is at least partially transparent. These
two layers are reciprocally superposed and fixed such that between them a plurality
of separate and sealed compartments is defined, each of which contains a mixture of
liquid crystals. This mixture of liquid crystals has the property of having a substantially
black colouring, apart from when the temperature is comprised within a predetermined
interval of values, in which case the liquid crystals are arranged such as to reflect/refract
the light and illuminate the relative compartment. By using mixtures of liquid crystals
that are different for each compartment is it therefore possible to make it so that
they illuminate alternatively, each for a different temperature interval, enabling
the thermometer to signal the temperature at present reached.
[0046] In the illustrated embodiment, the thermometer 210 comprises for example a lower
compartment 220 which is configured such as to illuminate, with a blue colour, up
to a temperature of about 45°C, an intermediate compartment 225 able to illuminate
with a green colour for a temperature comprised between about 45°C and 85°C, and an
upper compartment 230 able to illuminate with a red colour for a temperature of above
85°C. In this way, the illumination of the lower compartment 20 can signify that the
lubricating oil is too cold to guarantee an optimal lubrication; the illumination
of the intermediate compartment 225 can signify that the lubricating oil has reached
an optimum value; while the illumination of the upper compartment 230 can signify
that the lubricating oil is too hot and a dangerous condition has been reached. Returning
to the cover 170, the device 205 for signalling the level of the lubricating the oil
comprises a substantially semi-circular opening 235, which occupies about the remaining
half of the external surface of the end wall 200. This opening 235 opens internally
of a rear-lying cylindrical cavity 240 of the cover 170, which is arranged coaxially
with the crankshaft 150 and is in communication with the internal volume 145 of the
casing 145 (see figure 5). A disc 245 made of a transparent material, for example
plastic or glass, is snugly housed internally of the cylindrical cavity 240, and defines
therewith a window through which the inside of the casing 145 can be viewed. To prevent
undesired leakage of lubricating oil from the opening 235, a suitable annular seal
250 is interposed between the transparent disc 245 and the cylindrical cavity 240.
An opaque (i.e. not transparent) contrast disc 255 is also housed internally of the
cylindrical cavity 240, which disc 255 is interposed between the bearing 160 and the
transparent disc 245 in such a way as to define therewith a narrow gap 260. The contrast
disc 255 exhibits through-holes 265, by means of which the gap 260 is in hydraulic
communication with the internal volume of the casing 145.
[0047] In this way, the lubricating oil is arranged internally of the gap 260 at the same
level as internally of the casing 145, enabling a user to see the level directly through
the portion of the transparent disc 245 that closes the opening 235. The viewing of
the level of the lubricating oil is facilitated by the contrast disc 255 which, reflecting
at least in part the external light, is able to illuminate the slim layer of oil which
occupies the gap 260. At the opening 235 a graduated scale (or the equivalent) might
be present such as to indicate the predetermined levels for comparison with the actual
level of the lubricating oil.
[0048] Thanks to this viewing system, a user is also advantageously able to see and therefore
directly control also the colour and/or opacity of the lubricating oil, for example
in order to evaluate whether it is excessively dirty or exhausted or whether it has
been contaminated with water infiltrations during the functioning of the pump.
[0049] Obviously a technical expert in the sector might make numerous modifications of a
technical-applicational nature to the high-pressure pump described in the foregoing
without forsaking the scope of the invention as claimed in the following.
1. A pump (100) comprising a head (110), in which at least a cylinder is fashioned in
which a piston (105) is slidably housed, and a casing (145) fixed to the head (110),
which defines an internal volume in which a crankshaft (150) and at least a con rod
(155) are housed, which at least a con rod (155) connects the crankshaft (150) with
the piston (105), such as to be able to transform a rotary motion of the crankshaft
(150) into an alternating motion of the piston (105), characterized in that signaling means (210) of the temperature of lubricating oil contained in the internal
volume of the casing (145) are applied to the casing (145).
2. The pump (100) of claim 1, characterised in that the signalling means (210) further include measuring means of the temperature.
3. The pump (100) of claim 2, characterised in that the measuring and signaling means (210) comprise a thermochromic substance.
4. The pump (100) of claim 3, characterised in that the measuring and signalling means (210) are a liquid crystal thermometer.
5. The pump (100) of claim 4, characterised in that the liquid crystal thermometer is applied to the casing (145) by means of an adhesive.
6. The pump (100) of any one of the preceding claims, characterised in that it comprises signalling means (205) of the level of the lubricating oil contained
in the internal volume of the casing (145).
7. The pump (100) of claim 6, characterised in that the level signaling means (205) comprise a transparent body (245) which enable a
direct viewing of the level of the oil contained in the internal volume of the casing
(145).
8. The pump (100) of claim 7, characterised in that the transparent body (245) is facing an opaque contrast body (255), with which it
defines a gap (260) which is in hydraulic communication with the internal volume of
the casing (145).
9. The pump (100) of any one of the preceding claims, characterised in that the signalling means (210) of the temperature of the lubricant oil and/or the level
signalling means (205) are applied to a removable cover (170) of the casing (145).
10. The pump (100) of claim 9, characterised in that the cover (170) is aligned with the rotation axis of the crankshaft (150).