JP4678135B2 - pump - Google Patents

Description

  The present invention relates to a pump that moves a working fluid by changing a volume in a pump chamber by a movable wall such as a piston or a diaphragm, and particularly relates to a small high-power pump.

  Conventionally, this type of pump generally has a configuration in which a check valve is attached between an inlet channel and an outlet channel and a pump chamber whose volume can be changed. In addition, in the case of aiming to send liquid, there is a structure in which a thin portion is provided in the flow path upstream or downstream of the pump chamber, and pulsation due to intermittently driven liquid is reduced by deformation of the flow path. (For example, refer to Patent Document 1).

  In addition, by using a flow path structure with a large inertance value instead of the valve of the outlet flow path, the fluid inertia force is utilized, and the high output and high reliability corresponding to high load pressure and high frequency driving are achieved by the present inventors. There is a pump according to the invention. Also in the pump with this structure, a structure that can be deformed into the inlet-side flow path is used in order to prevent the suction efficiency of the pump from being reduced due to the pulsation of the inlet-side flow path (see, for example, Patent Document 2). ).

  In addition, a diaphragm driven by a piezoelectric element such as PZT, a pump chamber whose volume can be changed by the diaphragm, a hole through which fluid flows into the pump chamber, and a hole through which fluid flows out from the pump chamber are provided. A positive displacement pump provided with a check valve has been proposed (for example, Patent Document 3).

JP 2000-265963 A JP 2002-322986 A JP 61-171891 A

  However, the configuration of Patent Document 1 requires a check valve that is a fluid resistance element for both the inlet channel and the outlet channel. When the fluid passes through the two check valves, the pressure loss is large, In addition to the problem of not being able to handle high-frequency driving, if bubbles remain in the pump chamber, the pressure of the liquid in the pump chamber does not rise sufficiently in the process of reducing the volume of the pump chamber, and the predetermined discharge amount There is a problem that it cannot be obtained.

  In addition, since the pumps having the configurations of Patent Document 2 and Patent Document 3 have little change in the volume of the pump chamber due to the deformation of the diaphragm, if bubbles remain in the pump chamber, the inside of the pump chamber is reduced in the process of reducing the volume of the pump chamber. The liquid pressure will not rise sufficiently. As a result, it is conceivable that the flow rate characteristic of the pump is greatly deteriorated, and in the worst case, the liquid cannot be discharged.

  An object of the present invention is to provide a pump capable of discharging air bubbles and maintaining discharge performance even if air bubbles stay in the pump chamber.

The pump of the present invention includes a pump chamber whose volume can be changed by driving a piston or a movable wall, an inlet flow path for flowing the working fluid into the pump chamber, and an outlet flow path for flowing the working fluid from the pump chamber. And a fluid resistance element that opens and closes at least the inlet flow path, the combined inertance value on the inlet flow path side is set smaller than the inertance value on the outlet flow path side, and bubbles staying in the pump chamber It is further characterized by further comprising bubble discharging means for eliminating the above.
Here, for example, a diaphragm driven by an actuator such as a piezoelectric element can be employed as the movable wall. A check valve or the like can be employed as the fluid resistance element.
As the bubble discharging means, as will be described in detail later, for example, a sub pump chamber for applying pressure to the pump chamber, a pressurizing mechanism, a heating unit, and the like can be employed.

  According to the present invention, since the pump includes the bubble discharging means, the pump is started even when the bubbles are accumulated in the pump chamber, that is, when the working fluid is not filled in the pump chamber. be able to. In addition, if bubbles remain in the pump chamber, the pressure in the pump chamber may not increase sufficiently. However, by providing the aforementioned bubble discharge means, the bubbles that remain even when the pump is driven are discharged. Therefore, the performance of the pump, particularly the discharge amount of the working fluid can be maintained.

  Further, according to the above-described configuration, the pump chamber communicates with the outlet flow channel, and communicates with the main flow chamber whose volume can be changed by driving a piston or a movable wall, and the inlet flow channel, and is movable. It is preferable that the auxiliary pump chamber as the bubble discharging means whose volume can be changed by driving the wall.

  According to such a configuration, since the auxiliary pump chamber is provided on the inlet flow channel side as the bubble discharging means, the working fluid is sent from the inlet flow channel into the main pump chamber by driving the auxiliary pump chamber. The pressure in the chamber can be increased, and bubbles in the main pump chamber can be discharged.

  In the above-described configuration, the main pump chamber inlet flow path for flowing the working fluid into the main pump chamber, the main pump outlet flow path for flowing the working fluid from the main pump chamber, and the working fluid flow into the sub pump chamber. A sub pump chamber inlet flow channel and a sub pump chamber outlet flow channel for flowing out the working fluid from the sub pump chamber, wherein the main pump chamber inlet flow channel is the sub pump chamber outlet flow channel. preferable.

  In this configuration, since the main pump chamber inlet flow path is also used as the sub pump chamber outlet flow path, the working fluid flow path is shortened, and the pump can be downsized. Resistance can be reduced.

  The pump of the present invention includes a fluid resistance element that opens and closes the main pump chamber inlet channel, a fluid resistance element that opens and closes the sub pump chamber inlet channel, and a fluid resistance that opens and closes the sub pump chamber outlet channel. The fluid resistance element that opens and closes the main pump chamber inlet flow path is preferably a fluid resistance element that opens and closes the sub pump chamber outlet flow path.

In this way, for example, when the movable wall of the sub pump chamber is driven, the check valve as the fluid resistance element of the sub pump chamber inlet channel is closed, and the working fluid whose pressure is increased in the sub pump chamber Flows into the main pump chamber. Further, when the working fluid is discharged from the main pump chamber, the check valve as the fluid resistance element of the main pump chamber inlet channel is closed. By doing so, the pressure in the main pump chamber can be increased, so that bubbles staying in both pump chambers can be compressed and discharged out of the pump chamber.
In addition, since the fluid resistance element that opens and closes the main pump chamber inlet flow path is a fluid resistance element that opens and closes the sub pump chamber outlet flow path, even if it has two pump chambers, Since the valve functions in two, the structure of the pump can be simplified, the number of parts can be reduced, and the cost can be reduced. In addition, there is an effect of reducing fluid resistance.

  Further, according to the pump having the above-described configuration, the movable wall provided in the sub pump chamber is a diaphragm having a piezoelectric element attached to at least one surface, and the unimorph pump or the bimorph pump includes the sub pump chamber and the diaphragm. Is preferably configured.

  According to this configuration, the sub-pump chamber can be configured by a simple means of attaching the piezoelectric element to the diaphragm that has been used as one of the conventional pulsation reducing means of the flow path. Further, since the unimorph pump and the bimorph pump have a large amount of displacement of the diaphragm even at a small pressure, the pulsation absorbing means and the function of the auxiliary pump chamber as the bubble discharging means described above can be combined.

  Further, the pump having the above-described configuration is preferably provided with a drive switching control unit for switching driving between the sub pump chamber and the main pump chamber.

  The main pump chamber and the sub pump chamber are driven by the drive switching control unit, for example, when the pump drive is started, first the sub pump chamber is driven, and then the main pump chamber is driven to discharge internal bubbles. The driving of the main pump chamber can be continued or the driving can be alternately repeated, and a stable discharge amount of the working fluid can be obtained during the driving of the pump.

  Moreover, it is preferable that a drive electrode and a detection electrode are formed on the piezoelectric element.

  By configuring in this way, it is possible to detect the state of the sub pump chamber, in particular, it detects the pressure fluctuation in the sub pump chamber by the displacement of the piezoelectric element, and responds to the pressure fluctuation by the drive switching control unit described above. The main pump chamber and the sub pump chamber can be controlled.

  Moreover, it is preferable that the pump of this invention is equipped with the pressure detection part which detects the internal pressure of the said main pump chamber.

By adopting such a configuration, the state in the main pump chamber can be detected, and the pump corresponding to the state in the main pump chamber can be efficiently driven.
Furthermore, by combining with the state detection in the sub pump chamber by the detection electrode of the sub pump chamber described above. It is possible to drive the pump more efficiently corresponding to the state in both the pump chambers.

  Further, the above-described pump of the present invention is characterized in that a pressurizing mechanism is provided as the bubble discharging means for maintaining the pressure of the working fluid existing in the pump chamber in an increased state.

  According to such a configuration, when the pressure in the pump chamber decreases due to the bubbles remaining in the pump chamber and the discharge of the working fluid becomes impossible, the pressure of the working fluid existing in the pump chamber by the pressurizing mechanism Can be maintained in a raised state. As a result, the bubble volume is reduced, and the volume of the pump chamber can be compressed by driving a movable wall such as a piston or a diaphragm, and the bubbles in the pump chamber can be discharged.

  In the above-described configuration, it is preferable that the pressurizing mechanism includes a chamber whose volume can be changed and a flow channel which communicates the room whose volume can be changed to the outlet flow channel.

  In this way, the pressurizing mechanism pressurizes the volume changeable chamber, so that the volume changeable room communicates with the outlet flow path, so in the pump chamber communicating with the outlet flow path, High pressure can be generated easily.

  In the above-described configuration, it is preferable that the chamber capable of changing the volume is formed of an elastic body.

  According to such a configuration, the volume changeable chamber is made of an elastic body, so that the pressure rise due to the inflow of the working fluid into the volume changeable room is moderated, and the parts constituting the pump due to the pressure are damaged. Can be prevented. Further, the volume changeable room can also serve as a function of attenuating the pressure pulsation in the outlet channel. As a result, a change in pump performance due to the influence of external piping connected to the outlet channel can be prevented.

Furthermore, in the above-described configuration, it is preferable that the pressurizing mechanism is provided with a volume changing mechanism that applies pressure to change the volume of the room in which the volume can be changed.
Here, an actuator or the like can be employed as the volume changing mechanism.

  According to such a configuration, since the volume changing mechanism that changes the volume of the room in which the volume can be changed is provided, the volume of the room in which the volume can be changed can be controlled according to the state in the pump chamber.

  According to the present invention, the pressurizing mechanism includes a first state in which the working fluid flowing out from the pump chamber is guided to the volume changeable chamber, and the volume of the working fluid flowing out from the pump chamber can be changed. It is preferable that a flow path switching unit for switching between the second state where the room is shut off and the room is provided.

  In such a configuration, for example, when it is detected that bubbles are present in the pump chamber, the working fluid that has flowed out of the pump chamber is switched to the first state in which the volume can be changed to the chamber in which the volume can be changed. The working fluid in the pump chamber can be reliably pressurized by the elastic force of the elastic body constituting the. In addition, when there are no bubbles in the pump chamber, control is performed so that the working fluid is discharged outside the pump without being introduced into the chamber in which the volume can be changed, so that the pump can be driven efficiently.

  In the above-described configuration, it is preferable that a pressure detection unit that detects the internal pressure of the room in which the volume can be changed is provided.

  Thus, by providing the pressure detection means for detecting the pressure inside the room where the volume can be changed, the pressure inside the room where the volume can be changed can be controlled within an appropriate pressure range.

Moreover, it is preferable that the above-mentioned pump is provided with a pressure detection means in the pump chamber.
By doing so, it is possible to detect the pressure in the pump chamber, determine whether bubbles are retained in the pump chamber, and suitably control the driving of the pressurizing mechanism and the pump chamber.

  In the above-described configuration, it is preferable that the internal pressure of the room capable of changing the volume applied by the pressurizing mechanism is in a range of about 1 to 5 atm as a gauge pressure.

  By doing so, it is possible to sufficiently reduce the volume of bubbles remaining in the pump chamber until the components can be discharged without damaging the components constituting the pump due to the pressure.

  In addition, the pressurizing mechanism includes the volume-changeable chamber, a flow path that circulates through the outlet flow path, and an opening / closing member that opens and closes the flow path, and the pressurization mechanism includes the outlet flow path. It is preferable that the room capable of changing the volume and the outlet flow channel are circulated by being inserted into the outlet flow channel.

  In this way, the pressurizing mechanism is detachable, and when it is inserted into the outlet channel, the outlet channel and the pressurizing mechanism are connected to increase the pressure in the chamber in which the volume can be changed, thereby When the air is discharged and no bubbles remain in the pump chamber, the pump can be reduced in size and weight with the pressurizing mechanism removed.

  Further, the pump of the present invention is characterized in that a heat generating part as a bubble discharging means is provided inside the pump chamber.

  According to the present invention, the staying bubbles are heated by the heat generating part provided in the pump chamber, the staying bubbles are enlarged and moved from the stagnation point in the pump chamber, and the bubbles can be easily discharged.

  Moreover, it is preferable that the said heat_generation | fever part is accommodated in the inside of the wall of the said pump chamber, or is arrange | positioned at the corner part.

  It is known that bubbles are likely to stay in the pump chamber at the protruding portion of the corner of the pump chamber or the wall of the pump chamber. Therefore, the heat generating part is accommodated inside the wall of the pump chamber and arranged without a protruding part, or at least in the corner of the pump chamber. It is possible to make it difficult for air bubbles to stay, and to discharge the staying air bubbles from the corner of the pump chamber where air bubbles tend to stay.

Furthermore, in the above-described configuration, it is preferable that a plurality of the heat generating portions are provided.
By arranging a plurality of heat generating means in this way, the amount of energy per unit time supplied to the heat generating means can be reduced, and the remaining bubbles can be quickly discharged while preventing the pump from being destroyed.

Moreover, it is preferable that the pump mentioned above is provided with the pressure detection part which detects the internal pressure of the said pump chamber.
By doing so, it is possible to detect the pressure in the pump chamber, reliably determine whether air bubbles are retained in the pump chamber, and to suitably control the driving of the pump.

  Moreover, it is preferable to input a heat generation signal to the heat generating portion when driving the piston or the movable wall.

  In this way, the operating fluid in the pump chamber is heated by the heat generating portion while the piston or the diaphragm is operated, so that the pressure in the pump chamber can be increased and bubbles remaining in the pump chamber can be discharged.

  In the configuration described above, it is preferable that a pulse-like heat generation signal is input to the heat generating portion, and the piston or the movable wall is driven in synchronization with the heat generation signal.

  In addition, the above-described pump performs heat generation in the heat generating portion in a pulse shape, and operates the diaphragm in synchronization with the pulse, so that the energy consumed in the heat generating portion is effectively reduced while staying in the pump chamber. Bubbles can be discharged.

  Furthermore, it is preferable that the above-described pump performs heating by the heat generating portion so that the working fluid in contact with the heat generating portion changes phase.

  By doing so, bubbles due to phase change can be generated in the pump chamber, and a complicated and stagnation flow that flows out to the outlet channel can be generated in the pump chamber, so that bubbles remaining in the pump chamber can be easily discharged.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 17 show a pump according to an embodiment of the present invention.

1 to 3 show a pump 10 according to a first embodiment.
FIG. 1 is a longitudinal sectional view showing the structure of a pump 10 according to the first embodiment. In FIG. 1, a pump 10 has, as a basic configuration, a cup-shaped case 50 to which a laminated piezoelectric element 70 is fixed, an inflow path 21 for flowing in working fluid, an outflow path 28 for flowing out working fluid, and a sub pump chamber. 24 and a pump housing 20 having a main pump chamber 27.

  One end of the laminated piezoelectric element 70 is fixed to the inner bottom portion of the case 50 by fixing means such as adhesion, and covers both the upper surface of the edge of the case 50 and the upper surface of the other end of the stacked piezoelectric element 70. Thus, the main pump chamber diaphragm 60 is firmly fixed. The peripheral edge of the upper surface of the main pump chamber diaphragm 60 is fixed so that the pump casing 20 is kept airtight at the fixed portion. A main pump chamber 27 is formed in a space between the main pump chamber diaphragm 60 and a recess provided in the lower portion of the pump housing 20.

On the other hand, a recess is also provided in the upper part of the pump housing 20, and the sub pump chamber diaphragm 45 is fixed to the upper surface of the edge of the recess so as to keep airtight, thereby forming the sub pump chamber 24. The sub pump chamber diaphragm 45 is made of a thinner plate material than the main pump chamber diaphragm 60 and can be deformed by the internal pressure of the sub pump chamber 24. A plate-like piezoelectric element 71 is fixed to the upper surface of the sub pump chamber diaphragm 45. Both the sub pump chamber diaphragm 45 and the plate-like piezoelectric element 71 constitute a unimorph actuator.
The sub-pump chamber diaphragm 45 can also be configured as a bimorph actuator in which the plate-like piezoelectric elements 71 are pasted on both surfaces. In this case, it is necessary to consider the close contact of the plate-like piezoelectric elements 71 in contact with the working fluid. An actuator with a larger displacement can be configured.

Next, the configuration will be described along the flow path of the working fluid. An inflow path 21 is formed inside the inlet side connection pipe 30 protruding from the pump housing 20, and passes through the sub pump chamber inlet side valve hole 22 and the sub pump chamber inlet side valve seat hole 23, and then reaches the sub pump chamber 24. Communicating with A sub pump chamber inlet side check valve 41 as a fluid resistance element capable of opening and closing the sub pump chamber inlet side valve hole 22 is fixed to the peripheral edge of the sub pump chamber inlet side valve seat hole 23. A main pump chamber inlet side valve hole 25 and a main pump chamber inlet side valve seat hole 26 are provided between the sub pump chamber 24 and the main pump chamber 27. A main pump chamber inlet side check valve 42 as a fluid resistance element having an opening / closing member capable of opening and closing the main pump chamber inlet side valve hole 25 is fixed to the periphery of the main pump chamber inlet side valve seat hole 26.
An outflow passage 28 communicates with the main pump chamber 27. The outflow path 28 is continuously formed by a narrow tube portion connected to the main pump chamber 27 and an enlarged portion whose cross-sectional area is enlarged from the middle of the narrow tube portion. The outer periphery of the outlet channel is an outlet side connecting pipe 31.
Further, although not shown in the drawing, a tube made of silicon rubber having elasticity is connected to the inlet side connecting pipe 30 and the outlet side connecting pipe 31.

Next, the inertance value L of the flow path is defined. L = ρ × r / S, where S is the cross-sectional area of the flow path, r is the length of the flow path, and ρ is the density of the working fluid. When the differential pressure of the flow path is ΔP and the flow rate of the working fluid flowing through the flow path is Q, the equation of motion of the fluid in the flow path is modified using the inertance value L, so that ΔP = L × dQ / dt A relationship is derived.
In other words, the inertance value L indicates the degree of influence of the unit pressure on the time change of the flow rate. The larger the inertance value L, the smaller the time change of the flow rate, and the smaller the inertance value L, the greater the time change of the flow rate. .
In addition, the combined inertance value for parallel connection of multiple flow paths and serial connection of flow paths of different shapes is combined with the inductance values of individual flow paths in the same way as the parallel connection and series connection of inductances in electrical circuits. To calculate. For example, when two flow paths having inertance values L1 and L2 are connected in series, the combined inertance value is given by L1 + L2.

Further, the inlet flow path described below refers to a flow path from the main pump chamber 27 to the fluid inflow side end face of the main pump chamber inlet side valve hole 25. In the first embodiment, since the sub pump chamber 24 provided with the sub pump chamber diaphragm 45 as the pulsation absorbing means is connected in the middle of the flow path, from the main pump chamber 27 to the connection portion with the pulsation absorbing means. Refers to the flow path.
Therefore, when the sub pump chamber diaphragm 45 is highly rigid and has a small pulsation absorbing effect, the combined inertance of the main pump chamber inlet channel is calculated up to the position of the pulsation absorbing means such as a tube upstream of the sub pump chamber 24. There is a need to.

The outlet flow path refers to a flow path to the outlet end face of the outflow path 28 because a tube that is a pulsation absorbing means is connected to the outlet side connecting pipe 31.
Next, an inertance value of the opening / closing member of the check valve is defined. The inertance value of the opening / closing member is substantially related to the mass of the opening / closing member and the sectional area of the flow path (valve hole) closed by the opening / closing member, and the inertance value of the opening / closing member = the mass of the opening / closing member / the sectional area of the flow path closed by the opening / closing member. Is given by the square of. The inertance value of the opening / closing member indicates the degree of influence that the unit pressure has on the time change of the flow rate, as in the case of the flow channel inertance, when the opening / closing member opens from the state where the flow channel is completely closed and the flow rate is small. It can be considered that the flow rate changes with time as the inertance value increases, and the change with time of the flow rate increases as the inertance value decreases.

Next, an internal state when the pump according to the first embodiment is operated will be described with reference to FIG. This will be described with reference to FIG.
FIG. 2 shows a driving voltage of the laminated piezoelectric element 70 in the first embodiment of the pump 10 according to the present invention when the main pump chamber 27 and the sub pump chamber 24 are filled with a working fluid that is a liquid (water). 5 is a graph showing a waveform of a relationship between V) and pressure (MPa) expressed by absolute pressure in the main pump chamber 27 and time (ms). In FIG. 2, when the driving voltage increases, the laminated piezoelectric element 70 expands, so that the main pump chamber diaphragm 60 rises and compresses the volume of the main pump chamber 27. From FIG. 2, the pressure increase due to the compression of the main pump chamber 27 starts from the valley of the drive voltage, and after passing through the point where the increase gradient of the drive voltage is the largest, the internal pressure of the main pump chamber 27 rapidly decreases, It can be seen that the absolute pressure drops to near zero.

  This will be described in detail. First, when the main pump chamber 27 is compressed in a state where the main pump chamber inlet-side check valve 42 is closed, the main pump chamber is caused by a large inertance of the outflow passage (outlet flow passage) 28. The pressure in 27 rises greatly. Due to the increase in the internal pressure of the main pump chamber 27, the working fluid in the narrow tube portion is accelerated, and kinetic energy generating an inertia effect is stored. When the gradient of the expansion / contraction speed of the stacked piezoelectric element 70 is reduced, the working fluid continues to flow due to the inertial effect due to the kinetic energy of the working fluid stored in the outlet flow channel so far. The internal pressure drops rapidly and eventually becomes smaller than the pressure in the sub pump chamber 24.

  At this time, the main pump chamber inlet side check valve 42 opens due to the pressure difference, and the working fluid flows from the sub pump chamber 24 into the main pump chamber 27. At this time, the sum of the combined inertance value of the inlet flow path of the main pump chamber 27 and the inertance value of the main pump chamber inlet side check valve 42 which is an opening / closing member is sufficiently smaller than the aforementioned outlet flow path side inertance value. Inflow of working fluid occurs efficiently. The state in which the outflow and the inflow from the main pump chamber 27 occur simultaneously continues until the stacked piezoelectric element 70 contracts and starts to expand again. This is the situation of the flat portion of the pressure in the main pump chamber 27 in FIG.

  That is, since the pump 10 of the first embodiment continues to discharge and suck in for a long time, it can flow a large flow rate, and the pump chamber has an extremely high pressure, so that it can cope with a high load pressure. It is.

  At this time, in the sub pump chamber 24, the sub pump chamber diaphragm 45 is deformed by the internal pressure of the sub pump chamber 24 and absorbs pulsation. As a result, the inflow of the working fluid from the inflow passage 21 having a large inertance into the sub pump chamber 24 becomes a substantially steady flow with little pulsation, and the sub pump chamber inlet side check valve 41 continues to be opened. As described above, the sub pump chamber diaphragm 45 has an effect of suppressing the pulsation of the inflow passage 21 while keeping the inertance value on the inlet flow channel side of the main pump chamber 27 small due to the deformation. Further, at this time, since the sub pump chamber inlet side check valve 41 is kept open, problems such as generation of fluid resistance and fatigue failure do not occur.

Next, the priming operation when the pump 10 starts operation will be described with reference to FIGS. 1 and 3.
FIG. 3 is a block diagram of the drive circuit system according to the first embodiment of the present invention. The priming operation generally refers to an operation of filling a liquid with another pump when the main pump chamber 27 that does not have the ability to self-prime the liquid when gas is contained inside the pump. 3, the drive circuit system of the pump 10 includes a laminated piezoelectric element 70 that drives the main pump chamber diaphragm 60, a plate-like piezoelectric element 71 that drives the sub-pump chamber diaphragm 45, a laminated piezoelectric element 70, and a plate-like shape. A switching circuit 85 as a drive switching control unit for switching the driving of the piezoelectric element 71 and a pump drive control circuit 80 for controlling the driving of the pump 10 are configured.

  When the working fluid is not filled in the main pump chamber 27, the drive voltage generated by the pump drive control circuit 80 is a plate attached to the sub pump chamber diaphragm 45 by the switching circuit 85 in the initial stage of the pump operation. Applied to the piezoelectric element 71. The drive voltage is, for example, a sine wave. Since the sub pump chamber diaphragm 45 is a thin plate material and has a large displacement, the sub pump chamber 24 undergoes a large volume change due to the drive voltage. A sub pump chamber inlet side check valve 41 is disposed on the inlet side of the sub pump chamber 24, while a main pump chamber inlet side check valve 42 is disposed on the outlet side. The main pump chamber inlet side check valve 42 functions as an outlet side check valve of the sub pump chamber 24.

  As a result, since the sub pump chamber 24 has check valves on both the inlet side and the outlet side and has a large volume change amount, it functions as a pump capable of delivering both gas and liquid, and the sub pump chamber 24 and the main pump chamber 27 Since the gas inside is discharged and filled with the liquid as the working fluid, the pump operation can be performed by changing the volume of the main pump chamber 27. The switching circuit 85 is switched to apply a driving voltage to the laminated piezoelectric element 70 after a sufficient time has elapsed by a timer (not shown), and a high output operation is automatically enabled.

Further, during the operation of the main pump chamber 27, the operation state of the sub pump chamber diaphragm 45 can be measured by detecting the terminal voltage of the plate-like piezoelectric element 71. When bubbles or the like in the working fluid stay in the main pump chamber 27 and the performance of the pump deteriorates, the operation amount of the sub pump chamber diaphragm 45 becomes small. At this time, once the sub pump chamber diaphragm 45 is operated by the plate-like piezoelectric element 71 to discharge the bubbles, the drive voltage is switched so that the main pump chamber diaphragm 60 is again driven by the laminated piezoelectric element 70. The pump performance can be restored.
A priming operation is performed by performing the drive control as described above.

  Therefore, in Example 1 mentioned above, since the sub pump chamber 24 is equipped with the check valves 41 and 42 on both the inlet side and the outlet side and has a large volume variation, it functions as a pump capable of delivering both gas and liquid, Since the gas in the sub pump chamber 24 and the main pump chamber 27 is discharged and filled with the liquid as the working fluid, the pump operation can be performed by changing the volume of the main pump chamber 27.

The switching circuit 85 is switched to apply a driving voltage to the laminated piezoelectric element 70 in the main pump chamber 27 after a sufficient time has elapsed by the timer, and a high output operation is automatically enabled.
Further, during the operation of the main pump chamber 27, the operation state of the sub pump chamber diaphragm 45 can be detected by detecting the terminal voltage of the plate-like piezoelectric element 71. When bubbles or the like in the working fluid stay in the main pump chamber 27 and the performance of the pump deteriorates, the operation amount of the sub pump chamber diaphragm 45 becomes small. At this time, the sub-pump chamber diaphragm 45 is once operated by the plate-shaped piezoelectric element 71 to discharge the bubbles, and then the pump is switched by switching the drive voltage so that the main pump chamber diaphragm 60 is again driven by the laminated piezoelectric element 70. Performance can be restored.

Further, the main pump chamber inlet channel is a sub pump chamber outlet channel, and a fluid resistance element (check valve 42) that opens and closes the main pump chamber inlet channel is connected to the sub pump chamber outlet channel. Since it is a fluid resistance element that opens and closes, the flow path of the working fluid is shortened, and the fluid resistance of the flow path can be reduced. This also has the effect that the structure of the pump 10 can be simplified, the number of parts can be reduced, and low cost can be realized.
In the first embodiment described above, the case where the diaphragm 60 is employed as the means for changing the volume of the main pump chamber 27 has been described, but the object of the present invention can be achieved even if a piston is employed.

Next, a second embodiment of the present invention will be described with reference to FIG.
The pump of the second embodiment has the same basic structure as that of the first embodiment described above, but separates a part of the drive electrode 52 attached to the plate-like piezoelectric element 71 of the sub pump chamber 24 to form the detection electrode 53. It has a feature in the point.
FIG. 4 is a plan view viewed from the sub pump chamber diaphragm direction according to the second embodiment. In FIG. 4, the electrode 52 formed on the plate-like piezoelectric element 71 attached to the upper surface of the sub pump chamber diaphragm 45 is partially separated to form a detection electrode 53.

  Next, the function of this detection electrode will be described. During the priming operation such as when the pump is activated, the driving voltage is applied to the plate-like piezoelectric element 71 in the first embodiment described above. However, since the detection electrode 53 is independent in the second embodiment, it is possible to detect the movement of the sub pump chamber diaphragm 45 even during the priming operation (the drive voltage is applied to the plate-like piezoelectric element 71). ing. When the gas in the sub pump chamber 24 is discharged by the operation of the sub pump chamber diaphragm 45 and the sub pump chamber 24 is filled with the liquid, the movement of the sub pump chamber diaphragm 45 is reduced due to the difference in compression rate. Immediately afterwards, the inside of the main pump chamber 27 is also filled with the working fluid. Therefore, when a long pipe line is connected to the suction side, the completion time of the priming operation can be detected more accurately than the time management method, and the laminated type attached to the main pump chamber diaphragm 60 in a short time. The drive voltage can be switched to the piezoelectric element 70.

  In addition, when a drive circuit is independently connected to each piezoelectric element of the main pump chamber diaphragm 60 and the sub pump chamber diaphragm 45 and is always monitored by the detection electrode 53, in the event of malfunction of mixing of bubbles or the like during pump operation. However, it is possible to shift to the priming operation immediately without switching the circuit.

Therefore, according to the above-described second embodiment, since the detection electrode 53 is independent, it is possible to detect the movement of the sub pump chamber diaphragm 45 even during the priming operation, and accurately detect the completion timing of the priming operation. The driving voltage can be switched to the laminated piezoelectric element 70 of the main pump chamber diaphragm 60 in a short time.
In addition, the drive circuit is independently connected to the piezoelectric elements of the main pump chamber diaphragm 60 and the sub pump chamber diaphragm 45, and the detection electrode is constantly monitored, so that the circuit can be switched even in the case of malfunction due to mixing of bubbles or the like. It is possible to shift to the priming operation immediately without using it.

  Next, a third embodiment of the present invention will be described with reference to FIGS. The basic structure of the pump of the third embodiment is the same as that of the first embodiment described above, but is characterized in that a pressure sensor 90 is provided inside the main pump chamber 27. A description of parts common to the first embodiment is omitted.

  FIG. 5 is a partial longitudinal sectional view of a pump according to the third embodiment, and FIG. 6 is a block diagram of a pump drive circuit according to the third embodiment. In FIG. 5, a two-stage recess 35 is formed on the inner upper wall of the main pump chamber 27. A pressure sensor 90 made of the same material as the plate-like piezoelectric element 71 described above is fixed to the step of the recess 35 on the main pump chamber 27 side. An electrode (not shown) is formed on the surface of the pressure sensor 90 and is connected to a pump drive control circuit 80 described later (see FIG. 6). The above-described recess 35 has a gap that does not contact the wall when the pressure sensor 90 is bent.

  In FIG. 6, the drive circuit system of the pump 10 includes an internal pressure of the laminated piezoelectric element 70 that drives the main pump chamber diaphragm 60, a plate-like piezoelectric element 71 that drives the sub pump chamber diaphragm 45, and the main pump chamber 27. It comprises a pressure sensor 90 that detects and a pump drive control circuit 80 that controls the drive of the pump 10.

  5 and 6, when bubbles stay in the main pump chamber 27, the internal pressure of the main pump chamber 27 decreases. This state is detected by the pressure sensor 90, and the pump drive control circuit 80 outputs a drive signal to the plate-like piezoelectric element 71 to drive the sub pump chamber diaphragm 45 to increase the pressure in the sub pump chamber 24. As a result, bubbles remaining in the main pump chamber 27 are discharged out of the pump chamber. That is, the plate-like piezoelectric element 71 of the sub pump chamber diaphragm 45 is driven in synchronization with the pressure change in the main pump chamber 27.

  In the first to third embodiments described above, the pump is not provided with a check valve on the outflow path 28 side of the main pump chamber 27, but priming water is required even for a pump with a check valve. The same effect can be obtained in the pump.

  Therefore, according to the configuration of the third embodiment described above, by providing the pressure sensor 90 in the main pump chamber 27, it is possible to accurately detect when bubbles enter the main pump chamber 27 and malfunctions. it can. Further, in the third embodiment, since the plate-like piezoelectric element 71 of the sub pump chamber diaphragm 45 can be driven in synchronization with the main pump chamber diaphragm 60, the suction efficiency of the main pump chamber 27 is further improved. This makes it possible to provide a high-power pump.

Next, the pump of Example 4 which concerns on this invention is demonstrated based on FIG. 7, FIG. The fourth embodiment is characterized in that, on the basis of the technical idea of the first embodiment, the sub pump chamber 24 (see FIG. 1) is eliminated and a pressurizing mechanism 150 is provided as a bubble removing device.
FIG. 7 shows a longitudinal sectional view of the pump of the fourth embodiment. In FIG. 7, the pump 100 basically includes a cup-shaped case 50 to which the laminated piezoelectric element 70 is fixed, an inflow path 121 through which the working fluid flows, an outflow path 128 through which the working fluid flows out, and a pump chamber. The pump housing 120 includes 127 and a pressurizing mechanism 150 (enclosed by a broken line in the figure) for applying pressure to the pump chamber 127.

  In the cup-shaped case 50, one end of the multilayer piezoelectric element 70 is fixed to the inner bottom, and the diaphragm 60 is fixed over the edge of the case 50 and the upper surface of the other end of the multilayer piezoelectric element 70. ing. A pump housing 120 is fixed to the upper surface side of the diaphragm 60 so as to keep airtightness, and a pump chamber 127 is formed in a space between the diaphragm 60 and the lower portion of the pump housing 120.

An inflow path 121 and an outflow path 128 are formed toward the pump chamber 127. The inflow path 121 is provided with a check valve 122 as a fluid resistance element that opens and closes the inflow path 121 at a connection portion with the pump chamber 127. A part of the outer periphery of the cylindrical portion constituting the inflow passage 121 serves as an inlet connection pipe 130 for connection to an external pipe (not shown). In addition, the outflow path 128 is formed continuously with a narrow tube portion connected to the pump chamber 127 and an enlarged portion whose cross-sectional area is enlarged from the middle. The outer periphery of the cylindrical portion constituting the outflow path 128 is an outlet connection pipe 131 for connecting to an external pipe (not shown). Here, as the external piping, for example, a silicone rubber tube can be used.
Further, a pressure sensor 90 as a pressure detection unit that detects the internal pressure of the pump chamber 127 is fixed to the wall on the inner upper surface of the pump chamber 127.
The pump 100 is provided with a pressurizing mechanism 150 surrounded by a broken line in the drawing.

The pressurizing mechanism 150 includes a metal bellows 151 that is an elastic body, an actuator 170 that includes a piezoelectric element as a volume changing mechanism of the bellows 151, and a shut-off valve that blocks the flow of the working fluid in the outflow path 128. 140. The bellows 151 is tightly fixed to the side surface of the outlet connection pipe 131, and the opening 152 is connected to the flow path 132 that flows through the outflow path 128.
Inside the bellows 151, a volume changeable chamber is formed, and a pressure sensor 91 is provided as a pressure detection unit that detects the internal pressure of the bellows 151. The bellows 151 is changed in volume by the actuator 170. .

In the fourth embodiment, the actuator 170 has an end opposite to the bellows 151 fixed to the side of the inlet connecting pipe 130, and reciprocates by a drive unit (not shown) to compress the bellows 151. It is configured and driven by a pump drive control circuit 180 (see FIG. 8).
The cross-sectional area of the enlarged portion of the outflow passage 128 where the bellows 151 is connected is approximately twice the cross-sectional area of the narrow tube portion. This is because the flow velocity of the fluid passing through the flow path 132 to which the bellows 151 is connected is reduced, and the energy loss of the fluid that occurs during passage is reduced.

The relationship between the inertance values important for driving the pump in the present invention is omitted because it has been described in the first embodiment, but the inlet channel and the outlet channel in the fourth embodiment will be defined.
In the flow path into which the working fluid flows into the pump chamber 127, the flow path from the opening to the pump chamber 127 to the connection portion with the pulsation absorbing means is referred to as an inlet flow path. Here, the pulsation absorbing means is means for sufficiently attenuating pressure fluctuation in the flow path. Then, a flow path made of a material that is easily deformed by the internal pressure, such as rubber such as silicon rubber, other resin, and thin metal, an accumulator connected to the flow path, and a combination of pressure fluctuations of different phases The collecting flow path or the like that corresponds to the pulsation absorbing means.

In the fourth embodiment, since the external connection of the silicon rubber tube is connected to the inlet connection pipe 130, the flow path from the opening to the pump chamber 127 to the end face on the silicon rubber tube connection side in the inflow path 121, that is, the inflow path 121 itself is called an inlet channel.
The definition of the outlet channel is the same as that of the inlet channel, and the channel from the opening to the pump chamber 127 to the connection portion with the pulsation absorbing means in the channel from which the working fluid flows out from the pump chamber 127. Is called the outlet channel. In the fourth embodiment, since the bellows 151 in the middle of the outflow path 128 has an effect of absorbing pressure pulsation in a discharge mode described later, the outflow from the opening to the pump chamber 127 to the connection portion of the bellows 151. The path 128 is referred to as an outlet channel.

Next, the case where the pump 100 of the fourth embodiment is operated in the discharge mode will be described.
The discharge mode is an operation mode in which the working fluid flows out to the downstream side of the outflow path 128, and is performed when the pump chamber 127 is filled with the working fluid and bubbles are not retained. At this time, the shutoff valve 140 does not shut off the outflow path 128. The pressing portion 171 of the actuator 170 is separated from the bellows 151 as shown in FIG. As a result, the bellows 151 can be elastically deformed freely by the internal pressure, and the bellows 151 functions to attenuate the pressure pulsation in the outflow path 128. As an effect, no matter what kind of external pipe is connected to the outlet connecting pipe 131, the inertance value of the outlet channel is not affected, and the change in pump performance due to the connected external pipe can be prevented. In addition, if the chamber whose volume can be changed other than the bellows 151 is made of an elastic body, such an effect can be obtained.

Next, an internal state when the pump 100 according to the fourth embodiment is operated will be described. Since the internal state of the pump 100 is the same as that of the first embodiment (see FIG. 2) described above, the description thereof will be omitted in detail.
This will be described with reference to FIGS. In FIG. 2, the pump 100 of the fourth embodiment generates a high pressure in the pump chamber 127 and obtains a high output so that the pressure in the pump chamber 127 rises to about 2 MPa at the maximum. Therefore, in particular, when air bubbles stay in the pump chamber 127, the volume of the pump chamber 127 generated by the deformation of the diaphragm 60 before the stacked piezoelectric element 70 becomes the most expanded state is reduced. The amount of change (hereinafter referred to as “excluded volume”) is used to compress the bubbles, and does not contribute to the pressure increase in the pump chamber 127, and the pump operation is disabled. Therefore, it is important to quickly remove the retained bubbles.

Subsequently, a case where the pump 100 according to the fourth embodiment is operated in the bubble discharge mode will be described with reference to FIGS. 7 and 8.
FIG. 8 is a block diagram of a drive circuit of the pump 100 according to the fourth embodiment. Here, the bubble discharge mode is an operation mode performed when bubbles remain in the pump chamber 127. 8, the drive circuit system of the pump 100 includes a pressure sensor 90 (see FIG. 7) for detecting the pressure in the pump chamber 127, a pressure sensor 91 for detecting the pressure in the bellows 151, a pressurizing mechanism 150, A pump drive control circuit 180 for controlling them.

Next, a description will be given of how the pressure mechanism 150 operates to discharge the inherent bubbles when operating in the bubble discharge mode.
When the maximum pump chamber pressure detected by the pressure sensor 90 is smaller than the maximum pump chamber pressure during normal operation of the pump under the driving conditions, specifically, when it is less than half, the pump drive control circuit 180 It is determined that bubbles are staying inside the pump chamber 127. Then, a command is sent from the pump drive control circuit 180 to the pressurizing mechanism 150. According to the command, first, the shutoff valve 140 is in a state where the outflow path 128 is not shut off. Next, in FIG. 7, the actuator 170 extends the left end pressing portion 171 to the left to contact the bellows 151, further compresses the bellows 151 to the left, and greatly reduces the volume of the room constituted by the bellows 151. This is because the air bubbles accumulated in the room constituted by the bellows 151 flow out downstream from the shutoff valve 140.

  Next, the shutoff valve 140 shuts off the outflow path 128, and the actuator 170 is separated from the bellows 151 by contracting the pressing portion 171. Since the bellows 151 is formed of an elastic body, it returns to its original state by its own elastic force. By doing so, the inside of the bellows 151 is filled with the working fluid. Subsequently, the bellows 151 is compressed again by the actuator 170. As a result, the pressure of the working fluid existing from the interior of the bellows 151 to the pump chamber 127 can be increased.

  The bubbles staying in the pump chamber 127 are reduced in volume by being pressurized, and the bubble volume can be made sufficiently smaller than the excluded volume. At this time, the chamber of the bellows 151 is required to have a gauge pressure of about 1 atm or higher, preferably about 1 to 5 atm. Then, the pump drive control circuit 180 controls the actuator 170 that compresses the bellows 151 based on the detection value of the pressure sensor 91 that detects the pressure of the room constituted by the bellows 151, so that the inside of the bellows 151 can be appropriately adjusted. Pressure can be increased.

  Subsequently, when the laminated piezoelectric element 70 is driven, the pressure inside the pump chamber 127 is sufficiently increased as in the discharge mode, and the working fluid flows out from the pump chamber 127 to the outflow path 128. The bubbles staying in the pump chamber 127 ride on the flow of the working fluid in the pump chamber 127, and the bubbles staying in the pump chamber 127 are discharged into the bellows 151.

  A timer (not shown) that counts the time that the laminated piezoelectric element 70 is driven after the shutoff valve 140 shuts off the outflow path 128 is provided in the pump drive control circuit 180 and stays in the pump chamber 127. After this time is counted by this timer as a sufficient time for air bubbles to be discharged, the shutoff valve 140 releases the shutoff of the outflow passage 128 and contracts the actuator 170 to a position where it is separated from the bellows 151 to discharge the air bubbles. Exit mode.

At this time, although the internal pressure of the bellows 151 is increased by the working fluid discharged from the pump chamber 127, the deformation due to the pressure is designed to be suppressed within the elastic deformation allowable range. In this way, by configuring the chamber in which the volume can be changed with an elastic body, the pressure increase due to the inflow of the working fluid can be moderated and the components constituting the pump 100 can be prevented from being destroyed.
Further, the pump drive control circuit 180 may control the actuator 170 using the detection value of the pressure sensor 91 provided in the bellows 151 to reliably suppress the pressure increase inside the bellows 151.
Furthermore, a relief valve may be attached to the bellows 151 so that when the internal pressure of the bellows 151 is excessively increased, the relief valve is opened to reliably suppress an increase in pressure inside the bellows 151.

  Therefore, in the fourth embodiment, since the pressurizing mechanism 150 that maintains the pressure of the working fluid existing in the pump chamber 127 in an increased state is provided, the bubbles stay in the pump chamber 127. When the pressure in the pump chamber 127 drops and the discharge of the working fluid becomes impossible, the pressure of the working fluid existing in the pump chamber 127 can be maintained in an increased state. As a result, the volume of bubbles is reduced, and the volume of the pump chamber 127 can be compressed by driving the diaphragm 60 to discharge the bubbles in the pump chamber.

  Further, the pressurizing mechanism 150 pressurizes the bellows 151, but the chamber in which the volume of the bellows 151 can be changed communicates with the outflow path 128, and is easily high in the pump chamber 127 communicating with the outflow path 128. Pressure can be generated.

Furthermore, since the chamber whose volume can be changed is formed of an elastic body, the pressure rise due to the inflow of the working fluid into the chamber whose volume can be changed can be moderated, and damage to the parts constituting the pump due to the pressure can be prevented. In addition, by configuring the chamber in which the volume can be changed with an elastic body, it can also serve as a function of attenuating pressure pulsations in the outlet channel. As a result, a change in pump performance due to the influence of external piping connected to the outlet channel can be prevented.
(Modification 1 of Example 4)

As a modified example of the fourth embodiment described above, for example, the time counted by the timer of the pump drive control circuit 180 is arbitrarily set, and the bubble sensor is operated in the discharge mode after the bubble discharge mode ends, and the pressure sensor 90 in the pump chamber 127 is detected. You may check the value.
In this way, the bubble discharge mode operation is repeated until the bubbles are discharged, and the bubbles can be discharged reliably.

Further, in the above-described fourth embodiment, the operation of the bubble discharge mode is performed when it is determined that the bubbles are accumulated using the pressure sensor 90 in the pump chamber 127, and the operation of the bubble discharge mode is not performed unnecessarily. In addition, the bubble discharge mode operation may be performed every time an appropriate time elapses.
In this case, the pressure sensor 90 can be omitted, and the structure can be simplified.

Furthermore, when the inflow path 121 and the outflow path 128 are connected by an external pipe, the pressure in the pump chamber 127 is maintained increased by pushing the bellows 151 with the actuator 170 even without the shutoff valve 140. Can have a similar effect. In addition, the actuator 170 is provided to push the bellows 151. However, even if a display means that allows a human to grasp the output of the pressure sensor 91 is provided and the human operates the shut-off valve 140 and presses the bellows 151 while viewing the display, Similar effects can be obtained.
(Modification 2 of Example 4)

In the fourth embodiment, the pressure sensor 90 is provided in the pump chamber 127 as the pump chamber pressure detection unit, but other units can be used.
For example, there is a method of calculating the pressure inside the pump chamber 127 by measuring the strain of the diaphragm 60 with a strain gauge or a displacement sensor.
There is also a method of calculating the pressure in the pump chamber 127 by measuring the deformation of the case 50 with a strain gauge.
There is also a method of calculating the pressure in the pump chamber 127 by measuring the deformation of the opening / closing member with the check valve 122 closed with a strain gauge or a displacement sensor.
There is also a method of calculating the pressure in the pump chamber 127 by measuring the current for driving the laminated piezoelectric element 70 with a current sensor. Furthermore, there is a method in which a strain gauge is attached to the multilayer piezoelectric element 70 and the pressure in the pump chamber 127 is calculated from the applied voltage to the multilayer piezoelectric element 70 and the measured value of the strain gauge. At this time, any type of strain gauge may be used, such as one that detects the amount of strain by resistance change, capacitance change, or voltage change. Further, as a pressure detection means in the bellows 151, a structure in which the deformation of the bellows 151 is detected by a strain gauge and the pressure is calculated can be employed.
(Modification 3 of Example 4)

In the fourth embodiment, a piezoelectric element is used as the actuator 170. However, an electromagnetic type, a shape memory alloy type, or the like can be used in addition to the piezoelectric element. Among them, the shape memory alloy type is preferable because it can realize a large displacement with a simple structure.
Furthermore, the elastic body constituting the chamber capable of changing the volume may be made of rubber or resin material, but it is particularly preferable to use a metal made of a metal because evaporation of the working fluid can be prevented. Further, the shape may be a membrane or a diaphragm, but if the bellows shape as described in the fourth embodiment is used, the amount of displacement can be increased, and the stacked piezoelectric element 70 can be continuously operated for a long time in the bubble discharge mode. It is preferable in that air bubbles are easily discharged.

  Therefore, also in the configuration of the modified example of the above-described fourth embodiment, the same effect as that of the fourth embodiment can be obtained.

Next, a fifth embodiment according to the pump of the present invention will be described with reference to FIG.
The basic structure of the fifth embodiment is the same as that of the fourth embodiment (see FIG. 7), but the first state in which the working fluid that has flowed out of the pump chamber 127 is led to the chamber constituted by the bellows 151, and the pump chamber 127 The feature is that the second state in which the room composed of the bellows 151 is shut off from the flow of the working fluid that has flowed out, and the description will focus on the differences. In addition, the same code | symbol as Example 4 (refer FIG. 7) is provided to the same functional member.

  FIG. 9 shows a longitudinal section of the pump 100 of the fifth embodiment. In FIG. 9, a pressurizing mechanism 150 surrounded by a broken line is provided in the outflow path 128. The pressurizing mechanism 150 includes a metal bellows 151 that is an elastic body and a switching valve 190 that is a flow path switching unit (enclosed by a two-dot chain line in the drawing). The switching valve 190 includes a switching valve 182 that opens and closes the flow path 132 that communicates with the outflow path 128 from the opening 152 of the room formed by the bellows 151, and a switching valve 183 that opens and closes the outflow path 128.

  The function of the switching valve 190 is that the outflow path 128 from the pump chamber 127 to the switching valve 182, the outflow path 128 on the downstream side thereof, and the switching valve 183 are opened and communicated, and the switching valve 182 is closed and the bellows 151 The first connection state in which the room constituted by and the outflow path 128 are disconnected, and the outflow path 128 from the pump chamber 127 to the switching valve 182 and the room constituted by the bellows 151 are communicated, and the switching valve 183 is closed. Thus, the second connection state in which the outflow path 128 downstream of the switching valve 183 is blocked is switched.

The cross-sectional area of the outflow passage 128 where the switching valve 183 is disposed in the outflow passage 128 is approximately twice the cross-sectional area of the narrow flow passage portion connected to the pump chamber 127 in the outflow passage 128. . The reason for this is explained in Example 4. In addition, a pressure sensor 91 is provided inside the bellows 151 as bellows internal pressure detecting means for detecting the pressure in the room constituted by the bellows 151.
Here, the definition of the inlet flow channel and the outlet flow channel in Example 5 and the relationship between the inertance values are the same as in Example 4.

  Next, the case where the pump 100 of Example 5 is operated in the discharge mode will be described. In the fifth embodiment, in the discharge mode, the switching valve 190 enters the first connection state and causes the working fluid to flow out downstream of the outflow path 128. At this time, the pressure waveform in the pump chamber 127 when the laminated piezoelectric element 70 is driven is the same as that in the first embodiment (see FIG. 2). Therefore, as in the first embodiment, there is a situation in which discharge and suction occur simultaneously, a large flow rate can be flowed, and the pump chamber has an extremely high pressure, so that a high load pressure can be handled. On the other hand, as described in the first embodiment, when the bubbles stay inside the pump chamber 127, the operation suitable for the pump is not performed.

  Next, the operation in the bubble discharge mode performed when bubbles remain in the pump chamber will be described. Although not shown in the drawing, as the switching valve control system, when the pump drive control circuit determines that bubbles are staying in the pump chamber 127, a command is sent from the pump drive control circuit to the switching valve 190, and the switching is performed. The valve 190 is switched from the first connection state to the second connection state. At that time, since the inside of the bellows 151 is previously pressurized to a pressure of about 1 atm or more, preferably about 1 to 5 atm as a gauge pressure, the pump chamber 127 is pressurized to almost this pressure. The In this way, by configuring the chamber whose volume can be changed with an elastic body, it is possible to apply pressure only by the elastic force of the elastic body.

  Since the air bubbles staying in the pump chamber 127 are pressurized, the volume becomes smaller than the excluded volume of the pump chamber 127, so that the bellows 151 is driven in the same manner as in the fourth embodiment by driving the laminated piezoelectric element 70. It is discharged to the inside. Since the pump drive control circuit includes a timer (not shown) that counts the time during which the laminated piezoelectric element 70 is driven after the switching valve 190 is switched to the second connection state, the pump chamber 127 is provided. After this time is counted by this timer as a sufficient time for the air bubbles staying inside to be discharged, the switching valve 190 is switched to the first connection state and the bubble discharge mode is terminated.

  At this time, although the internal pressure of the bellows 151 is increased by the working fluid discharged from the pump chamber 127, the deformation due to the pressure is designed to be suppressed within the elastic deformation allowable range. In addition, a relief valve (not shown) is attached to the bellows 151, and when the internal pressure of the bellows 151 is excessively increased, the relief valve is opened to suppress the pressure increase inside the bellows 151, and the gauge pressure is about 1 atm. Desirably, the internal pressure may be maintained at a constant value between about 1 atmosphere and 5 atmospheres. By this bubble discharge mode, the retained bubbles are eliminated, and the pump performance can be recovered normally.

Next, a bellows pressurization mode performed in order to always maintain the pressure inside the bellows 151 at a gauge pressure of about 1 atm or higher, preferably between about 1 atm and 5 atm, will be described with reference to FIG.
The pressure in the bellows 151 is detected by a pressure sensor 91 provided in the bellows 151. When the detected pressure is less than about 1 atm in gauge pressure, a command is sent from the pump drive control circuit 180 to the pressurizing mechanism 150, and the switching valve 190 is switched to the second connection state. Next, the diaphragm 60 is driven by the laminated piezoelectric element 70, and the fluid flows out from the pump chamber 127 to the outflow path 128 in the same manner as in the discharge mode.

  Then, the working fluid flows into the bellows 151 via the switching valve 182, and the inside of the room constituted by the bellows 151 is pressurized. When the pump drive control circuit 180 confirms that the pressure in the bellows 151 has reached a gauge pressure of about 1 atm or higher, preferably between about 1 atm and 5 atm, based on the detected value of the pressure sensor 91, the pump A command is sent from the drive control circuit 180 to the pressurization mechanism 150, the switching valve 190 is switched to the first connection state, and the bellows pressurization mode is terminated. By performing this operation mode, the inside of the bellows 151 can always be maintained at a set pressure even when there is a leak in the switching valve 190 or the like, and a bubble discharge mode can be prepared.

  In the fifth embodiment described above, the switching valve 190 is composed of two valves, but an integrated three-way valve or the like may be used. In addition, the bellows 151 is provided with a hole (not shown) that can be closed with good airtightness. When air bubbles are accumulated in the bellows 151, the air bubbles can be discharged from the hole. It has become.

  As a modification of the fifth embodiment described above, when the relationship between time and the amount of leakage from the bellows 151 is known, the bellows is added at predetermined time intervals without providing the pressure sensor 91 in the bellows. Pressure mode may be performed. In this case, the amount of leakage is converted from the time from the end of the previous bellows pressurization mode to the start of the current bellows pressurization mode, and a working fluid having a volume equal to the amount of leak is transferred from the pump chamber 127 to the bellows 151. The laminated piezoelectric element 70 can be driven for a time required to flow into the inside.

Furthermore, without providing the pressure sensor 91, a relief valve (not shown) may be provided in a room constituted by the bellows 151, and the bellows pressurizing mode may be performed at predetermined time intervals. In this way, when the inside of the bellows 151 is pressurized beyond the pressure set by the relief valve when the bellows pressurization mode is performed, the relief valve opens and the working fluid is released, so that the inside of the bellows 151 is kept at a constant pressure. Can be maintained.
In the above description, the pressure sensor described in the fourth embodiment can be used in the same manner as the pressure sensor 90 in the pump chamber 127 and the pressure sensor 91 in the bellows 151 for detecting the pressure in the pump chamber 127.

  Therefore, according to the fifth embodiment, the pressurizing mechanism 150 has the bellows from the first state in which the working fluid flowing out from the pump chamber 127 is guided to the chamber of the bellows 151 and the flow of working fluid flowing out from the pump chamber 127. A flow path switching means for switching between the second state where the room 151 is shut off is provided. By doing so, the working fluid in the pump chamber 127 can be reliably pressurized by the elastic force of the elastic body constituting the chamber capable of changing the volume.

Furthermore, the pressure sensor 91 which detects the pressure inside the room in which the volume can be changed is provided, and the pressure inside the room in which the volume can be changed can be controlled within an appropriate pressure range. Moreover, since the pressure sensor 90 is also provided in the pump chamber 127, it is possible to determine whether or not bubbles remain in the pump chamber 127.
Furthermore, since the pressure applied by the pressurizing mechanism 150 is about 1 to 5 atm in gauge pressure, the volume of bubbles staying in the pump chamber can be discharged without damaging the components that make up the pump. It can be made small enough.

Next, a sixth embodiment of the pump according to the present invention will be described with reference to FIGS. In the sixth embodiment, the basic structure of the pump other than the pressurizing mechanism is the same as that of the above-described fourth embodiment, and different points will be described in detail. The sixth embodiment is used without connecting external piping to the outflow passage 128, and does not require the switching valve (see FIGS. 7 and 9) described in the fourth and fifth embodiments. The pressurizing mechanism 150 is detachably attached to the outflow path 128.
FIG. 10 shows a longitudinal sectional view of a pressure mechanism alone according to the sixth embodiment. In FIG. 10, the pressurizing mechanism 150 includes a bellows 151 and a valve case 153 to which the bellows 151 is fixed and which stores the valve 156.

As described in the above-described fourth embodiment, the bellows 151 is formed with a volume-changing chamber in which the working fluid is retained and an opening 152, and is closely attached to the end of the valve case 153.
The valve case 153 communicates the opening 152 that circulates with the bellows 151, the outlet 155 into which the outlet connection pipe 131 of the pump 100 is inserted (see FIG. 11), the opening 152 and the insertion 155, A valve mounting hole 154 into which the valve 156 is mounted and a rod insertion hole 160 into which the rod 159 of the valve 156 is inserted are formed. In the middle of the insertion port 155, a seal member 165 for preventing the working fluid from leaking from the connection portion between the outlet connection pipe 131 and the insertion port 155 is mounted.

The valve 156 is connected by a rod 159 and a washer 157 that fixes the rod 159 with the rod insertion hole 160 interposed therebetween. The washer 157 has a through hole 158 through which the working fluid flows. Further, between the washer 157 and the inner wall of the insertion port 155, a coil spring 161 that biases the valve 156 so as to seal the rod insertion hole 160 described above is configured.
Further, the chamber in which the volume of the bellows 151 can be changed is pressurized by the elastic force of the bellows 151 to a range of about 1 to 5 atm as a gauge pressure as in the fourth and fifth embodiments.

  FIG. 11 is a partial longitudinal sectional view showing a state in which the above-described pressurizing mechanism 150 is mounted on the outlet connection pipe 131 of the pump 100. In FIG. 11, the insertion port 155 of the pressurizing mechanism 150 is inserted into the outlet connection pipe 131. At this time, the distal end portion of the outlet connection pipe 131 is brought into contact with the washer 157 to compress the coil spring 161 and the valve 156 is moved to a position where the rod insertion hole 160 is opened. At this time, the room surrounded by the outflow path 128 and the bellows 151 is in a state where the working fluid can flow through the through hole 158.

Next, the case where the bubbles of the pump 100 in the sixth embodiment are not retained will be described. This will be described with reference to FIGS.
In the normal use in which bubbles do not stay, the pump 100 of the sixth embodiment is used by separating the outflow path 128 and the pressurizing mechanism 150 and discharging the working fluid from the outflow path 128. Also in this case, the principle of causing the working fluid to flow out to the outflow path 128 is as described in the first embodiment. Therefore, when bubbles stay in the pump chamber 127, the pressure increase in the pump chamber is hindered and the pump performance is greatly reduced. Therefore, it is important to quickly remove the bubbles.

Next, the case where bubbles stay in the pump chamber 127 will be described.
When bubbles remain, the outflow amount of the working fluid from the outflow path 128 is greatly reduced. Therefore, when the user observes that the amount of outflow from the outflow path 128 has decreased, the user inserts the pressurizing mechanism 150 into the outlet connecting pipe 131 (shown in FIG. 11). In FIG. 11, when the washer 157 is pushed at the end of the outlet connecting pipe 131 with a force stronger than the elastic force of the coil spring 159, the coil spring 161 contracts, the valve 156 opens, and the operation provided on the washer 157. The fluid through-hole 158 and the opened valve 156 communicate with each other, and the outflow path 128 is connected to the inside (room portion) of the bellows 151.

  In this way, when the inside of the pump chamber 127 is pressurized, the volume of the bubbles staying inside the pump chamber 127 is reduced. Therefore, as described in the fourth and fifth embodiments, The remaining bubbles can be discharged from the outflow path 128 into the bellows 151. At this time, it is preferable to provide a lock mechanism that makes it difficult to disconnect the outflow passage 128 and the bellows 151 from each other.

  Also in this embodiment, a relief valve may be provided in the bellows 151 to suppress an increase in pressure inside the bellows. Further, a hole that can be closed with good airtightness may be provided in the bellows 151 so that bubbles accumulated in the bellows can be removed.

  Therefore, according to the above-described sixth embodiment, the pressurizing mechanism is detachable, and when inserted into the outlet channel, the outlet channel and the pressurizing mechanism are communicated with each other so that the pressure of the chamber whose volume can be changed is reduced. When the bubbles in the pump chamber are increased and the bubbles are not retained in the pump chamber, the pump can be reduced in size and weight with the pressurizing mechanism removed.

Next, a seventh embodiment of the pump according to the present invention will be described with reference to FIGS. The seventh embodiment is characterized in that the basic structure of the pump and the discharge operation of the working fluid are the same as those of the first to sixth embodiments described above, but a heat generating part is provided as a bubble removing means in the pump chamber. ing. Therefore, the relationship between this heat generating part and bubble elimination will be described in detail.
FIG. 12 shows a longitudinal section of a pump 200 according to the seventh embodiment. In FIG. 12, the pump 200 has, as a basic structure, a cup-shaped case 50 to which the laminated piezoelectric element 70 is fixed, an inflow path 221 for flowing in the working fluid, an outflow path 228 for flowing out the working fluid, and a pump chamber. A pump housing 220 having 227 and a ring-shaped heater 212 in the pump chamber 227 are provided.

  In the case 50, one end of the multilayer piezoelectric element 70 is fixed to the inner bottom, and the diaphragm 60 is fixed to both the edge of the case 50 and the other end of the multilayer piezoelectric element 70. A pump housing 220 is fixed to the upper surface side of the diaphragm 60 so as to maintain airtightness, and a pump chamber 227 is formed in a space between the diaphragm 60 and the lower portion of the pump housing 220.

  An inflow path 221 and an outflow path 228 are formed toward the pump chamber 227. The inflow path 221 is provided with a check valve 222 as a fluid resistance element that opens and closes the inflow path 221 at the connection with the pump chamber 127. A part of the outer periphery of the cylindrical portion constituting the inflow path 221 is an inlet connection pipe 230 for connection to an external pipe (not shown). A part of the outer periphery of the cylindrical portion constituting the outflow passage 228 serves as an outlet connection pipe 231 for connection to an external pipe (not shown). Here, for example, a silicone rubber tube can be used as the external piping (not shown).

  Here, the inlet channel is the inflow channel 221 itself, and the outlet channel is the outflow channel 228 itself. As described above, the inertance value is set such that the combined inertance value on the inlet channel side is smaller than the inertance value on the outlet side.

  Further, a ring-shaped heater 212 is fixed to the outer peripheral corner portion of the wall on the inner upper surface of the pump chamber 227. The heater 212 is fitted to the corner of the upper wall of the pump chamber 227 so as to be kept airtight, and is fixed so as not to protrude from the surface of the upper wall of the pump chamber 227 toward the pump chamber.

FIG. 13 is a plan view of the pump housing 220 shown in FIG. 12 viewed from the pump chamber side. In FIG. 13, the heater 212 is disposed at a position where bubbles at the corners of the pump chamber 227 tend to stay. This heater 212 is a ceramic substrate made of alumina or the like and a resistor is fixed thereon and further covered with an insulating film. Although there are various resistors, those having a high melting point are preferable, and specifically, platinum or a platinum-based alloy is desirable. Although not shown, a lead wire for energizing the heater 212 passes through the pump housing 220 and is taken out of the pump.
Note that a pressure sensor 90 (not shown) is provided in the pump chamber 227 (see FIG. 15).

A modification of the heater 212 in the seventh embodiment will be described with reference to FIG.
In FIG. 14, the heater 212 is formed of a disk-shaped thin plate, and is fixed over a wide range of the upper surface wall of the pump chamber 227 excluding the peripheral portions of the inflow path 221 and the outflow path 228. The heater 212 is fitted so as not to protrude from the surface of the upper surface wall of the pump chamber 227.

Next, a case where the pump 200 of the seventh embodiment is operated in the working fluid discharge mode will be described.
The pump operation in this discharge mode is a mode in which voltage is applied only to the piezoelectric element 70 without energizing the heater 212. Since this discharge mode has been described in the first to sixth embodiments, a description thereof will be omitted here. At this time, as described above, when the bubbles stay in the pump chamber 227, the pressure in the pump chamber decreases and the performance of the pump deteriorates, so the mode is shifted to the bubble discharge mode.

Next, the case where the pump 200 according to the seventh embodiment is operated in the bubble discharge mode will be described with reference to FIG. 15 (see also FIG. 12).
FIG. 15 is a block diagram of the drive circuit system of the pump 200. In FIG. 15, the drive circuit system of the pump 200 includes a pressure sensor 90 as a pump chamber pressure detecting means in the pump chamber 227, a heater 212, an energizing circuit 265 that controls the heater 212, and a pump that drives and controls the pump 200. And a drive control circuit 280.

  When the maximum pump chamber pressure detected by the pressure sensor 90 when operating the pump 200 in the discharge mode is smaller than the maximum pump chamber pressure during normal operation of the pump under the driving conditions, specifically, 50% In the following cases, the pump drive control circuit 280 determines that bubbles are staying inside the pump chamber 227, and shifts the operation mode from the discharge mode to the bubble discharge mode. Then, a signal is sent from the pump drive control circuit 280 to the energization circuit 265, and the energization circuit 265 starts energizing the heater 212 by the signal.

  Since the heater 212 is arranged at the corner where the flow is stagnant and bubbles are likely to stay as described above, the heat generated by the heater 212 heats the staying bubbles in the vicinity thereof and expands its volume. Can be made. When the size of the staying bubbles does not fit in the stagnation region in this way, the staying bubbles are moved by the flow in the pump chamber 227 driven by the diaphragm 60 and can be discharged from the outflow path 128. The bubble discharge mode ends when a predetermined time has passed.

At this time, when a plurality of heaters 212 are configured, by configuring the energization circuit 265 to sequentially switch the energization to each heater according to time, the energization current can be reduced without changing the heat generation amount of the energized heater, This is preferable in that the energization circuit 265 can be reduced in size.
On the other hand, the working fluid present on the surface of the heater 212 may generate a heat quantity that causes a phase change, and bubbles may be generated due to the phase change from various locations on the surface of the heater 212. In this method, since the working fluid corresponding to the generated bubble volume flows out to the outflow passage 228, when the energization to the heater 212 is stopped and the phase change is completed, an amount of working fluid corresponding to the volume of the outflowing working fluid flows in. The fluid passes through the check valve 222 from the passage 221 and flows into the pump chamber 227. At this time, bubbles due to phase change are generated from various locations on the surface of the heater 212, so that the flow generated inside the pump chamber 227 is complicated and has no stagnation, and is at the corner of the pump chamber, which becomes a stagnation region in the discharge mode flow Accumulated retained bubbles can be discharged.

  Further, energization from the energization circuit 265 causes the heater 212 to generate a sufficient amount of heat for the working fluid present on the surface to reach an overheated state, causing film boiling in which film-like bubbles are generated on the entire surface of the heater 212. May be. In this method, the volume of bubbles generated by the phase change increases, and the volume of the working fluid that flows out from the pump chamber 227 to the outflow passage 228 by one energization increases, so that the retained bubbles can be easily discharged. preferable.

FIG. 16 shows a modification of the heater 212. In FIG. 16, the heater 212 includes two heaters, a heater 213 disposed on the inflow path 221 side and a heater 214 disposed on the outflow path 228 side.
At this time, the phase of the energization current to each heater is shifted by the energization circuit 265 (see FIG. 15). Thus, after the internal pressure of bubbles generated by film boiling on one heater surface exceeds the maximum value, the internal pressure of bubbles generated by film boiling on the other heater surface reaches the maximum value.

  Furthermore, when the heater 213 near the opening to the pump chamber 227 of the outflow passage 228 and the far heater 214 are provided, the far heater 214 is energized first, the phase is delayed, and the energization of the heater 213 is started. This is preferable because a flow from the corner of the chamber 227 toward the outflow passage 228 is easily generated. Of course, the number of heaters 212 may be two or more.

  When the phase of the working fluid on the surface of the heater 212 is changed, the diaphragm 60 may be in either a stopped state or a driven state. However, if the diaphragm 60 is driven, the flow in the pump chamber becomes more complicated and stays. This is preferable in that air bubbles can be easily removed.

Further, in the seventh embodiment, the heater 212 is energized with a pulse current, the heater 212 generates heat in a pulse shape, and the diaphragm 60 is driven in the direction of decreasing the volume of the pump chamber 227 in synchronization with the heat generation. The pump drive control circuit 280 and the energization circuit 265 can also be controlled.
While reducing the energy consumed in the heat generating part, it is possible to effectively discharge the bubbles remaining in the pump chamber.

  Further, it is preferable to start and stop energization of the heater 212 a plurality of times during one bubble discharge mode because a more complicated flow is generated in the pump chamber and the retained bubbles are easily discharged. Furthermore, it is preferable to operate in the discharge mode after completion of the bubble discharge mode and check the detection value of the pressure sensor 91 because the operation in the bubble discharge mode can be repeated until the retained bubbles are reliably discharged.

  Therefore, according to the seventh embodiment described above, the heater 212 is provided in the pump chamber 227, and the pressure in the pump chamber 227 is increased by heating and the bubble volume is compressed, thereby discharging the bubbles in the pump chamber 227. can do.

  Further, since the heater 212 is fitted so as not to protrude from the wall of the pump chamber 227 and is disposed at least at the corner of the pump chamber 227, it is possible to prevent bubbles from remaining in the protruding portion where the bubbles are likely to stay. At the same time, the accumulated bubbles can be discharged from the corner of the pump chamber 227.

Further, when a plurality of heaters 212 are arranged, it is possible to reduce the amount of energy per unit time supplied to the heaters 212 and to quickly discharge the remaining bubbles while preventing the pump from being destroyed.
In addition, since the pressure sensor 90 is provided in the pump chamber 227, it is possible to reliably determine whether or not bubbles remain in the pump chamber 227 and discharge the bubbles in the pump chamber 227 as described above.

  In addition, since the heat generation of the heater 212 is performed in the form of pulses and the diaphragm 60 is operated in synchronization with the pulses, the bubbles that have effectively accumulated in the pump chamber 227 while reducing the energy consumed by the heater 212. Can be discharged.

  Further, by performing drive control to perform heating so that the working fluid in contact with the heater 212 has a heat generation amount that changes in phase, bubbles due to a phase change can be generated in the pump chamber 227, and to the outflow path 228 in the pump chamber 227. Since a complicated flow without stagnation that flows out can be produced, there is an effect that bubbles staying in the pump chamber 227 can be discharged.

  Further, in the above description, the bubble discharge mode is performed when it is determined that the bubbles have accumulated using the pressure sensor 91 and the bubble discharge mode is not performed unnecessarily. Alternatively, the bubble discharge mode may be operated. In this case, the pressure sensor 91 can be omitted and can be easily implemented.

  Furthermore, in the above description, as the pump chamber pressure detecting means, the configuration in which the pressure sensor is provided in the pump chamber 227 has been described, but other methods may be used. As another method, for example, there is a method of measuring the strain of the diaphragm 60 with a strain gauge or a displacement sensor and calculating the pressure inside the pump chamber 227. There is also a method of calculating the pressure in the pump chamber 227 by measuring the deformation of the valve plate with the check valve 222 closed with a strain gauge or a displacement sensor. There is also a method for calculating the pressure in the pump chamber 227 by measuring the current for driving the piezoelectric element 70 with a current sensor. Further, there is a method in which a strain gauge is attached to the piezoelectric element 70 and the pressure in the pump chamber 227 is calculated from the applied voltage to the piezoelectric element 70 and the measured value of the strain gauge. At this time, any type of strain gauge may be used, such as one that detects the amount of strain by resistance change, capacitance change, or voltage change.

  The shape of the diaphragm 60 is not limited to a circle. The check valve 222 is not limited to a passive valve that opens and closes due to a fluid pressure difference, but may be an active valve type that can be controlled to open and close with other force.

In addition, this invention is not limited to the above-mentioned Example, The deformation | transformation in the range which can achieve the objective of this invention, improvement, etc. are included in this invention.
For example, in the above-described seventh embodiment, the combined inertance value on the inlet flow path side is smaller than the combined inertance value on the outlet flow path side, and the heater 212 is used as a bubble discharging means in a small, high pressure pump due to the inertia effect of the working fluid. Although employed, such a bubble discharging means can also be employed in a pump using a unimorph diaphragm as shown in FIG. 17, for example.

  FIG. 17 is a longitudinal sectional view of a pump employing a unimorph diaphragm. In FIG. 17, the differences from the seventh embodiment will be described in detail. The pump 200 includes a unimorph diaphragm 260 as a diaphragm and check valves 222 and 242 as fluid resistance elements in both the inflow path 221 and the outflow path 228. In FIG. 17, a diaphragm 260 is airtightly fixed to an edge of a cup-shaped case 250, and a plate-like piezoelectric element 71 is fixed to a surface of the diaphragm 260 on the case 250 side. The pump housing 220 is fixed to the upper portion of the diaphragm 260 so as to keep airtight, and a pump chamber 227 is formed between the diaphragm 260 and the lower portion of the pump housing 220.

  An inflow path 221 and an outflow path 228 are communicated with the pump chamber 227, a check valve 222 that is a fluid resistance element is disposed in the inflow path 221, and a check valve that is a fluid resistance element is disposed in the outflow path 228. A valve 242 is arranged. In addition, a planar heater 212 serving as a heat generating portion is disposed on an upper wall surface constituting the pump chamber 227 of the pump housing 220. The heater 212 is fixed to the pump housing 220 so as to be kept airtight, and does not protrude from the pump housing 220 to the pump chamber side.

Since the shape and material of the heater 212, the mounting position on the pump housing 220, and the like can be configured in the same manner as in the seventh embodiment and the modified example of the seventh embodiment, the description thereof is omitted.
The discharge mode of this pump will be described.
When a voltage is applied to the plate-like piezoelectric element 71, the diaphragm 260 is deformed into a convex shape toward the pump chamber 227 due to the deformation of the plate-like piezoelectric element 71 in the radial direction. Return to shape. This pump uses the deformation of the diaphragm 226, and when the check valves 222 and 242 close the flow path, the diaphragm 260 is deformed in a direction in which the volume of the pump chamber 227 decreases, so that the inside of the pump chamber 227 Pressurize the liquid. When the pressure inside the pump chamber 227 rises above the pressure downstream of the check valve 242, the check valve 222 opens and the liquid flows out to the outflow path 228.

  Next, the pressure inside the pump chamber 227 is decreased by deforming the diaphragm 260 in a direction in which the volume of the pump chamber 227 increases. Then, first, the check valve 242 is closed, and when the pressure inside the pump chamber 227 decreases below the pressure upstream of the check valve 222, the check valve 222 opens and liquid flows into the pump chamber 227 from the inflow path 221. To do. The above operation is repeated to transfer the working fluid.

  Even in the pump having the structure as described above, by providing the heater 212 as the bubble discharging means, the bubbles in the pump chamber can be discharged outside the pump chamber, and the pressure in the pump chamber can be suitably maintained. The discharge amount of the working fluid can be ensured.

  Further, in the above-described embodiment, the shapes of the diaphragms 60 and 45 are illustrated as circular, but are not limited to circular. The check valves 41 and 42 may be not only a passive valve that opens and closes due to a fluid pressure difference, but also an active valve type that can be controlled to open and close by other force. Furthermore, any piezoelectric element that moves the diaphragm 60 may be used as long as it expands and contracts. However, in this pump structure, the piezoelectric element and the diaphragm are connected without a displacement enlargement mechanism, and the diaphragm is operated at a high frequency. Therefore, by using a piezoelectric element having a high response frequency as in this embodiment, an increase in flow rate by high frequency driving can be realized, and a small and high output pump can be realized. Similarly, a giant magnetostrictive element having high frequency characteristics may be used. In addition to water, other liquids such as oil may be used as the working fluid.

  Therefore, according to the first to seventh embodiments described above, by providing the bubble discharging means, even if the bubbles stay in the pump chamber, the pump can discharge the bubbles and maintain the discharge performance. Can be provided.

  The pump of the present invention can be used in various industries using small liquid transfer pumps.

1 is a longitudinal sectional view showing a pump according to Embodiment 1 of the present invention. The graph which shows the internal state of the pump which concerns on Example 1 of this invention. The block diagram which shows the drive circuit of the pump which concerns on Example 1 of this invention. The top view which shows the subpump chamber diaphragm of the pump which concerns on Example 2 of this invention. The fragmentary longitudinal cross-section which shows the pump which concerns on Example 3 of this invention. The block diagram which shows the drive circuit of the pump which concerns on Example 3 of this invention. The longitudinal cross-sectional view which shows the pump which concerns on Example 4 of this invention. The block diagram which shows the drive circuit of the pump which concerns on Example 4 of this invention. The longitudinal cross-sectional view which shows the pump which concerns on Example 5 of this invention. The longitudinal cross-sectional view which shows the pressurization mechanism which concerns on Example 6 of this invention. The fragmentary longitudinal cross-section which shows the pump which concerns on Example 6 of this invention. The fragmentary longitudinal cross-section which shows the pump which concerns on Example 7 of this invention. The top view which shows the heater which concerns on Example 7 of this invention. The top view which shows the modification of the heater which concerns on Example 7 of this invention. The block diagram which shows the drive circuit of the pump which concerns on Example 7 of this invention. The top view which shows the other modification of the heater which concerns on Example 7 of this invention. The longitudinal cross-sectional view which shows the pump which concerns on the other Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,100,200 ... Pump, 20 ... Pump housing | casing, 21 ... Inflow passage, 24 ... Sub pump chamber, 27 ... Main pump chamber, 28 ... Outflow passage, 30 ... Inlet side connection pipe, 31 ... Outlet side connection pipe, 41, 42 ... check valve, 50 ... case, 45, 60 ... diaphragm, 70 ... piezoelectric element, 71 ... plate-like piezoelectric element.

Claims (7)

A pump chamber whose volume can be changed by driving a piston or a movable wall;
An inlet channel for flowing liquid into the pump chamber;
An outlet channel through which liquid flows out of the pump chamber;
A liquid resistance element that opens and closes at least the inlet channel;
A pressurizing mechanism for increasing and maintaining the pressure of the liquid present in the pump chamber ,
The synthetic inertance value on the inlet flow path side is set smaller than the synthetic inertance value on the outlet flow path side,
The pressurizing mechanism includes a volume changeable chamber, and a flow path that communicates the volume changeable chamber and the outlet flow path, and is disposed inside the liquid from the volume changeable chamber to the pump chamber. A pump characterized in that bubbles that are present are reduced, and the bubbles are discharged from the outlet channel by being placed on a liquid flow from the pump chamber . The pump according to claim 1 , wherein
The pump capable of changing the volume is formed of an elastic body. The pump according to claim 1 , wherein
The pump according to claim 1, wherein the pressurizing mechanism includes a volume changing mechanism that applies pressure to change the volume of the room in which the volume can be changed. The pump according to any one of claims 1 to 3,
A pump characterized by further comprising blocking means for blocking the outlet channel. The pump according to any one of claims 1 to 4 ,
The pump further comprising means for suppressing an increase in internal pressure when the internal pressure of the pressurizing mechanism reaches a predetermined pressure. The pump according to any one of claims 1 to 5 ,
A pump comprising a pressure detection unit for detecting an internal pressure of the room in which the volume can be changed. The pump according to any one of claims 1 to 6 ,
The pump characterized in that the internal pressure of the chamber capable of changing volume applied by the pressurizing mechanism is in the range of about 1 to 5 atm in gauge pressure.

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