JP2005282498A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump in which discharge flow rate is increased in a micro pump in which a pipe line element for generating inertia effect of fluid is provided to the discharge side of a pump chamber. <P>SOLUTION: The pump is equipped with an inlet flow passage 111 making working fluid flow in, an outlet flow passage 115 making working fluid flow out, a pump chamber 114 allowing change of a volume by a diaphragm 121, a connection flow passage 113 for connecting the inlet flow passage 111 and the outlet flow passage 115, an inlet connection flow passage 112 making working fluid flow into a pump chamber 114 from the inlet flow passage 111, a first check valve disposed between the connection flow passage 113 and the outlet flow passage 115, and a second check valve disposed between the pump chamber 114 and the outlet flow passage 115. Inertance of the connection flow passage 113 is made to become relatively smaller than each inertance of the inlet flow passage 111 and the outlet flow passage 115. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pump that moves a working fluid by changing the volume of a pump chamber using a diaphragm, and more particularly to a small-sized pump having a large flow rate.

Conventionally, in a small pump that moves the working fluid by changing the volume of the pump chamber using a diaphragm, a high-power micropump has been developed in which a pipe element that generates the inertia effect of the fluid is provided immediately after the discharge side of the pump chamber. ing. (See Non-Patent Document 1 and Patent Document 1)
JP 2002-322986 A “High output of micropump using inertial effect of fluid” The Japan Society of Mechanical Engineers Robotics Mechatronics Lecture '03 Proceedings 2A1-2F-E4

  In a small pump that moves the working fluid by changing the volume of the pump chamber by a diaphragm, a micropump in which a pipe element that generates an inertia effect of fluid is provided immediately after the discharge side of the pump chamber is disclosed in Non-Patent Document 1. As shown in the figure, it was possible to discharge a volume larger than the excluded volume, and the discharge flow rate was large. However, there are applications in which a larger discharge flow rate is required while the pressure is low, such as circulation of cooling water.

  An object of the present invention is to provide a pump in which a discharge flow rate is further increased in a micropump in which a pipe line element that generates an inertia effect is provided on the discharge side of a pump chamber.

  The pump according to the present invention connects an inlet flow path through which a working fluid flows in, an outlet flow path through which the working fluid flows out, a pump chamber whose volume can be changed by a diaphragm, and the inlet flow path and the outlet flow path. A connection flow path, an inlet connection flow path for flowing a working fluid from the inlet flow path to the pump chamber, a first check valve between the connection flow path and the outlet flow path, and the pump chamber And a second check valve between the outlet channel and the outlet channel, and the inertance of the connection channel is smaller than the inertance of each of the inlet connection channel and the outlet channel.

  According to this invention, in the pump chamber expansion process in which the pump chamber volume increases, a flow in the direction of the pump chamber can be made in the inlet connection flow path, and kinetic energy is stored in the fluid in the inlet connection flow path. On the other hand, while the kinetic energy in the discharge direction is present in the fluid in the outlet channel, the fluid continues to flow from the connection channel to the outlet channel due to the inertia effect. In the pump chamber compression stroke in which the pump chamber volume decreases, the fluid in the inlet connection flow path stores kinetic energy flowing in the direction of the pump chamber, and the inflow into the pump chamber continues due to its inertial effect. As a result, a flow rate obtained by adding the flow rate of the inflowing fluid and the flow rate eliminated by the volume reduction of the pump chamber can flow out from the pump chamber to the outlet channel. Furthermore, the inertia effect by the kinetic energy in the discharge direction stored in the fluid in the outlet channel by the outflow flow rate can be used. Therefore, it is possible to increase the discharge flow rate.

  Moreover, in the above-mentioned structure, it is preferable that the inertance of the said inlet connection flow path is larger than the inertance of the said outlet flow path.

  According to this structure, in the pump chamber compression stroke in which the pump chamber volume decreases, the volume of the pump chamber is utilized by utilizing the inertia effect due to the kinetic energy of the fluid flowing in the direction of the pump chamber stored in the fluid in the inlet connection flow path. A flow rate higher than the flow rate eliminated by the reduction can be discharged from the pump chamber to the outlet channel.

  Moreover, in the above-mentioned structure, it is preferable that the inertance of the said inlet connection flow path is 2 times or more larger than the inertance of the said outlet flow path.

  According to this structure, in the pump chamber compression stroke in which the pump chamber volume decreases, the decrease in the flow velocity of the fluid flowing in the direction of the pump chamber stored in the fluid in the inlet connection flow path is reduced, and the flow velocity of the fluid in the outlet flow path Can be increased, and more fluid can flow out from the pump chamber to the outlet channel when the volume of the pump chamber is reduced.

  In the above structure, it is preferable that the flow path opening / closing member of the first check valve also serves as the flow path opening / closing member of the second check valve.

  According to this structure, the number of parts constituting the pump can be reduced, the cost can be reduced, and the reliability can be improved.

  In the above structure, it is preferable that the flow path opening / closing member is a ball.

  According to this structure, the flow of the working fluid toward the outlet channel is hardly disturbed by the plate-like valve body, so that the fluid resistance when flowing in the check valve can be reduced. Further, when the valve body is a ball, when the check valve is opened and the working fluid flows, the flow cross-sectional area of the working fluid increases even if the valve body moves slightly, so the flow amount is reduced. There is also an effect that can be increased.

  Further, since the ball valve is rotatable, the contact portion is always changed, and the performance degradation due to wear or the like can be reduced.

  In the above-described structure, the member including the inlet channel, the outlet channel, the pump chamber, the inlet connection channel, and the connection channel can be manufactured by a lost wax manufacturing method. preferable.

  According to this structure, a complicated flow path part can be made into one part, and an assembly becomes easy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 5 show a pump according to an embodiment of the present invention.

  FIG. 1 is a longitudinal sectional view of the pump of the first embodiment. The right direction in the figure is the direction in which the working fluid flows during pump operation. In FIG. 1, this pump includes a diaphragm 121 that changes the volume of the pump chamber 114 by expansion and contraction of the actuator 123, a pump chamber body 101, a connection pipe 102 in which a connection flow path 113 is formed, and an actuator 123 in the inside. Are arranged, and an actuator bottom surface housing 104 to which the actuator 123 is fixedly fixed.

  The pump chamber body 101 includes a pump chamber 114, an outlet channel 115 that is connected to the pump chamber 114 and flows out the working fluid, an inlet channel 111 into which the working fluid flows, an inlet channel 111, and the pump chamber 114. An inlet connection flow path 112 to be connected is formed. Further, the inner diameter of the outlet channel 115 gradually increases toward the downstream, and the inner diameter after the enlargement is substantially equal to that of the inlet channel 111.

  In addition, a check valve (second check valve) that prevents the flow from the outlet flow path 115 toward the pump chamber 114 is press-fitted and fixed at the junction between the pump chamber 114 and the outlet flow path 115. As shown in FIG. 2, this check valve is composed of a valve seat 201 provided with a through-hole and a valve plate 203, and the vicinity of the outer periphery of the valve plate 203 is joined to the valve seat 201 by spot welding. Yes.

  The description of the pump structure of this embodiment will be continued using FIG. 1 again.

  The pump chamber body 101 is provided with a recess for press-fitting and fixing the connection pipe 112, and the connection pipe 112 is press-fitted and fixed therein. A check valve (first check valve) that prevents the flow from the outlet flow path 115 toward the connection flow path 113 is press-fitted and fixed at the junction of the connection flow path 113 and the outlet flow path 115. The structure of this check valve is the same as that of the second check valve, and is composed of a valve seat 202 and a valve plate 204.

  In the opening of the pump chamber 114 of the pump chamber body 101, a thin disc-shaped diaphragm 121 made of stainless steel or the like is closely fixed in a recess provided on the periphery of the pump chamber 114. The actuator side case 103 is press-fitted into the recess, and the pump chamber body 101 and the actuator side case 103 are integrated while pressing the diaphragm 121.

  The actuator bottom case 104 is closely fixed to and integrated with the other end of the actuator side case 103, and one end of the actuator 123 is fixed to the actuator bottom case 104. The actuator 123 is a piezoelectric element and expands and contracts when a driving voltage is applied from an external control circuit (not shown). An actuator pedestal 122 is fixed to the other end of the actuator 123, and the actuator pedestal 122 is fixed in close contact with the diaphragm 121.

  Although not shown, the outer periphery of the inlet flow path 111 is connected to an external connection tube made of silicon rubber to introduce a working fluid, and the outer periphery of the outlet flow path 115 is also connected to an external connection tube made of silicon rubber (not shown) to operate. Discharge fluid.

  Next, the inertance 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 relation of ΔP = L × dQ / dt is obtained by modifying the equation of motion of the fluid in the flow path using the inertance L. Is derived.

  That is, the inertance L indicates the degree of influence of the unit pressure on the time change of the flow rate. The larger the inertance L, the smaller the time change of the flow rate, and the smaller the inertance L, the greater the time change of the flow rate.

  In addition, the combined inertance related to the parallel connection of a plurality of flow paths and the series connection of a plurality of flow paths having different shapes is performed by combining the inertances of the individual flow paths in the same manner as the parallel connection and series connection of inductances in an electric circuit. What is necessary is just to calculate. For example, when two flow paths having inertances L1 and L2 are connected in series, the combined inertance is given by L1 + L2.

  Here, the inertance of the connection channel 113 is calculated from the junction with the inlet channel 111 to the through hole provided in the valve seat 202 constituting the first check valve. In addition, since an external connection tube made of silicon rubber having a high pulsation absorbing effect is connected, the inertance of the outlet channel 115 causes the external connection tube from the downstream side of the valve plate 203 and the valve plate 204 constituting the check valve. It is calculated up to the end face connected to. Further, the inertance of the inlet connection channel 112 is calculated from the junction with the inlet channel 111 to the junction with the pump chamber.

  Then, compared to the smaller one of the inertances of the inlet connection channel 112 and the outlet channel 115, the diameter of the connection channel 113 is increased so as to be smaller. Since the inertance of the connection flow path 113 is preferably as small as possible, the connection pipe 102 can be made of a highly stretchable material such as a thin metal pipe, a bellows structure metal pipe, or a synthetic resin pipe.

  Further, the inertance of the inlet connection channel 112 is made thinner and longer so that the inertance of the outlet channel 115 becomes smaller. Here, it is more desirable that the inertance of the inlet connection flow path 112 is twice or more as compared with the inertance of the outlet flow path 115.

  Next, operation | movement of the pump of this invention is demonstrated using FIG.

  FIG. 3A shows a pump chamber expansion stroke in which the pump chamber volume increases. And the arrow shown in the figure has shown the flow in each flow path.

  First, when the diaphragm 121 is operated in a direction in which the volume of the pump chamber 114 increases, the pressure in the pump chamber 114 is lower than the pressure in the outlet channel 115 in accordance with the compressibility of the working fluid. Then, the second check valve is closed due to the pressure difference. When the pressure in the pump chamber 114 falls below the pressure in the inlet channel 111, a flow toward the pump chamber 114 is generated in the inlet connection channel 112, and kinetic energy is stored in the fluid in the inlet connection channel 112. The

  On the other hand, while there is kinetic energy in the discharge direction stored in the fluid in the outlet channel 115 by the immediately preceding pump chamber compression stroke, the inertial effect causes the first check valve to remain open from the connection channel 113. The fluid continues to flow to the outlet channel 115. In particular, when the load pressure to the pump is relatively low, the flow from the connection flow path 113 to the outlet flow path 115 due to the inertial effect can always be continued during the pump operation, and the discharge flow rate is large. When the load pressure is relatively high, the flow rate in the outlet channel 115 decreases quickly, and the flow in the outlet channel 115 may stop in the middle of the pump chamber expansion stroke. At that time, the flow in the connection channel 113 is also stopped.

  Next, FIG. 3B shows a pump chamber compression stroke in which the pump chamber volume decreases.

  When the diaphragm 121 operates in a direction in which the volume of the pump chamber 114 decreases, the pressure in the pump chamber 114 increases according to the compressibility of the working fluid. Then, the second check valve is opened due to the pressure difference. The fluid in the inlet connection flow path 112 stores the kinetic energy that flows in the direction of the pump chamber 114, and the inflow into the pump chamber 114 continues due to its inertial effect. The flow rate added by the flow rate (hereinafter referred to as the “excluded flow rate”) is discharged from the pump chamber 114 to the outlet channel 115.

  At this time, the pressure in the pump chamber 114 rises higher than the pressure in the inlet flow path 111 and the flow rate in the inlet connection flow path 112 decreases, but the inertance in the inlet connection flow path 112 is made larger than the inertance in the outlet flow path. Thus, the decrease in the flow rate can be suppressed, and the fluid exceeding the excluded flow rate can be efficiently discharged from the outlet channel 115. More desirably, by making the inertance of the inlet connection flow path 112 more than twice the inertance of the outlet flow path 115, the flow rate reduction of the inlet connection flow path 112 becomes smaller, and the flow rate higher than the exclusion flow rate is more efficiently obtained. It can be discharged.

  On the other hand, when the second check valve is opened and the pressure in the outlet channel 115 rises, the first check valve is closed due to the pressure difference with the pressure in the connection channel 113, and the outlet flow from the pump chamber 114. The backflow of the fluid that has flowed out to the channel 115 to the connection channel 113 is prevented. When the kinetic energy flowing in the discharge direction is stored in the fluid in the outlet channel 115 and an inertia effect is generated, the first check valve is opened, and the working fluid flows from the connection channel 113 to the outlet channel 115. At this time, since the inertance of the connection flow path 113 is smaller than the smaller one of the inertance of the inlet connection flow path 112 or the outlet flow path 115, the flow rate in the connection flow path 113 is reduced. The time change can be increased, and the fluid can efficiently flow from the connection channel 113 to the outlet channel 115. Here, when the inertance of the connection channel 113 is set to be ½ or less compared to the smaller one of the inertance of the inlet connection channel 112 and the outlet channel 115, the flow rate in the connection channel 113 is reduced. It is more preferable that the time change can be increased twice or more.

  By repeating the above pump chamber expansion stroke and pump chamber compression stroke, the pump of the present invention can discharge at a higher flow rate than before.

  Next, a second embodiment of the pump of the present invention will be described with reference to FIG.

  The second embodiment is based on the structure of the first embodiment (see FIG. 1), and the pump chamber body 101, the connecting pipe 102, and the actuator side housing 103 are integrally formed by the lost wax manufacturing method. In addition, the first check valve and the second check valve in the first embodiment are configured by one flow path opening / closing member, and the flow path opening / closing member has a ball shape. The same functional parts as those in the first embodiment are assigned the same numbers, and the description of the common parts with the first embodiment is omitted below.

  FIG. 4 is a longitudinal sectional view of the pump of the second embodiment. In FIG. 4, a pump casing 301 is obtained by integrally forming the pump chamber body 101, the connecting pipe 102, and the actuator side casing 103 in the first embodiment by a lost wax manufacturing method. A check valve unit constituted by the ball valve seat 401 and the ball 402 is fixed to the junction of the connection channel 113, the pump chamber 114, and the outlet channel 115. In the opening of the pump chamber 114 of the pump housing 301, a thin disc-shaped diaphragm 121 made of stainless steel or the like is closely fixed in a recess provided at the periphery of the pump chamber 114. Here, the assembly order is such that the check valve unit is first press-fitted from the opening side of the pump chamber 114 of the pump housing 301, and then the diaphragm 121 is fixed.

  Next, the operation of the check valve unit is shown in FIG. The arrows shown in the figure indicate streamlines. The ball 402 can move in the vertical direction inside the ball valve seat 401, and the connection state of the flow path is switched by one ball 402.

  According to the check valve structure using this ball, since the flow of the working fluid is hardly disturbed by the plate-like valve body, the fluid resistance of the check valve can be reduced. In addition, since the valve body is a ball, the flow cross-sectional area of the working fluid is increased by a slight movement of the valve body, so that the flow amount can be increased. Further, since the ball valve is freely rotatable, the contact portion is constantly changed, and a decrease in performance due to wear or the like can be reduced.

  The pump of this embodiment operates as a pump when the load pressure is relatively low during the pump chamber expansion stroke, and the flow continues from the connection flow path 113 to the outlet flow path 115, and the operation is the same as that of the pump of the first embodiment. Since it is the same as that when the load pressure is relatively low, it will be omitted.

  In addition, this invention is not limited to above-mentioned Example 1-2, 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 first and second embodiments, the volume of the pump chamber 114 is changed by the diaphragm 121, but not only the diaphragm but also a piston can be employed.

  As described above, according to the first and second embodiments, it is possible to provide a pump that discharges a larger flow rate than before.

  The pump of the present invention can be used as a cooling device for electronic equipment, a fluid actuator, a power source for a piston of a micro hydraulic press, and the like.

1 is a longitudinal sectional view of a pump according to Embodiment 1 of the present invention. 1 is a structural diagram of a check valve of a pump according to Embodiment 1 of the present invention. Explanatory drawing of operation | movement of the pump which concerns on Example 1 of this invention. The longitudinal cross-sectional view of the pump which concerns on Example 2 of this invention. The check valve structure figure of the pump concerning Example 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Pump chamber body, 111 ... Inlet flow path, 112 ... Inlet connection flow path, 113 ... Connection flow path, 114 ... Pump chamber, 115 ... Outlet flow path, 121 ... Diaphragm, 201 ... Constructing a second check valve , 202 ... valve seat constituting the first check valve, 203 ... valve plate constituting the second check valve, 204 ... valve plate constituting the first check valve, 402 ... ball

Claims (6)

An inlet flow path for flowing working fluid;
An outlet channel through which the working fluid flows out;
A pump chamber whose volume can be changed by a diaphragm,
A connection channel connecting the inlet channel and the outlet channel;
An inlet connection flow channel for flowing a working fluid from the inlet flow channel to the pump chamber;
A first check valve between the connection channel and the outlet channel;
A second check valve is provided between the pump chamber and the outlet channel, and the inertance of the connection channel is smaller than the inertance of each of the inlet connection channel and the outlet channel. pump. The pump according to claim 1, wherein
A pump characterized in that an inertance of the inlet connection channel is larger than an inertance of the outlet channel. The pump according to claim 1, wherein
The pump characterized in that the inertance of the inlet connection channel is at least twice as large as the inertance of the outlet channel. The pump according to any one of claims 1 to 3,
The flow path opening / closing member of the first check valve also serves as the flow path opening / closing member of the second check valve. The pump according to claim 4,
The pump characterized in that the flow path opening / closing member is a ball. The pump according to any one of claims 1 to 4,
A member comprising a member including the inlet channel, the outlet channel, the pump chamber, the inlet connection channel, and the connection channel is manufactured by a lost wax manufacturing method.

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