JP2006063960A - Check valve and diaphragm pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize excellent responsiveness, reduce a valve chest in size and prevent the influence by air bubbles in a check valve and a diaphragm pump using it. <P>SOLUTION: The check valve includes the valve chest 11 formed by a ceiling wall 8 having an inlet 8a of a fluid, a bottom wall 9 having an outlet 9a of a fluid, and a side wall, and a valve element 12a supported within the valve chest 11 in a cantilever-like state such that the proximal end of the valve element 12a is secured to the side wall and the top end thereof is free. The valve element 12a is arranged on the inlet 8a. The bottom wall 9 is formed with a valve seat 9b having a slope 9b2 which is inclined in such a manner that it is more spaced from the ceiling wall 8 gradually along the valve element 12a from the proximal end toward its top end. Since the valve element 12a supported in the cantilever-like state moves between the ceiling wall 8 and the valve seat 9b so that the movement of the valve element 12a is restricted by the valve seat 9b having the slope 9b2, the amount of movement of the valve element 12a is reduced when opening/closing the valve, thereby shortening the response time of the valve from the opened state to the closed state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a check valve suitable for a pump that controls a flow rate of a trace amount of liquid and a diaphragm pump using the check valve.

In recent years, in the fields of fuel cells, medical care, analysis, and the like, various pumps have been developed for controlling a minute liquid flow rate with high accuracy.
Conventionally, for example, Patent Document 1 discloses a check valve for a piezoelectric vibrator pump using a piezoelectric vibrator as a drive source and a cantilever-shaped valve body formed in a frame (valve box / valve chamber). Proposed. In this check valve, one end of a support arm is inserted into and supported by the inner wall of the frame portion, and the other end is a valve body capable of closing the valve hole. In addition, this valve body and the support arm are comprised by the board | plate body of integral things, such as a metal and a plastics.

Japanese Laid-Open Patent Publication No. 4-72479 (page 4, right column, FIG. 1)

The following problems remain in the conventional technology.
Conventionally, a cantilever-shaped valve body generally uses a metal, a resin material, or a rubber material as its material. This valve body is opened by pressure, but because the valve body is rigid, the amount of deformation is not stable due to parts and assembly variations, that is, the time for closing is not stable, and the response is unstable. There was inconvenience that it was.
When the valve body is formed of a resin material, the valve body has a certain thickness, and thus a certain amount of force is required for deformation in order to be in an open state. Therefore, if the longitudinal dimension is increased, the required force can be reduced. However, the size (volume) of the valve chamber is increased, and bubbles are retained by the gas dissolved in the liquid being vaporized. As a result, the liquid conveying capacity of the pump is affected. There is also concern about plastic deformation of the valve body.
Further, when the valve body is formed of a rubber material, there is no concern about plastic deformation, but there is a limit to reducing the thickness, and there are the same inconveniences as for resin as to the force and size for deformation.

  The present invention has been made in view of the above-described problems, and provides a check valve that has good responsiveness, can reduce the valve chamber, and is less susceptible to bubbles, and a diaphragm pump using the check valve. Objective.

  The present invention employs the following configuration in order to solve the above problems. That is, the check valve of the present invention has a valve chamber formed by a top wall having a fluid inlet, a bottom wall having a fluid outlet, and a side wall, a base end fixed to the side wall in the valve chamber, and a distal end. And a valve body that is supported as a free end and is cantilevered and disposed on the inlet, and is gradually spaced from the top wall along the valve body from the base end toward the tip end. Thus, a valve seat having an inclined surface that is inclined is formed.

  In this check valve, since the inclined surface is formed on the valve seat on the bottom wall, the valve can be opened and closed by moving the cantilevered valve body between the top wall and the valve seat having the inclined surface. At this time, the amount of movement of the valve element is restricted by the valve seat having the inclined surface, and the response time from opening to closing is shortened. Further, since the amount of movement is restricted to a small amount, the valve chamber can be small and is not easily affected by bubbles. Further, even if a soft valve body is used, the valve body is hardly deformed because it is regulated by the inclined surface of the valve seat.

  The check valve of the present invention is characterized in that the valve seat is formed with a groove portion having one end connected to the discharge port and the other end extended from the tip of the valve body. That is, in this check valve, since the groove is formed in the valve seat, when the fluid pushes the valve body into the open state, the valve body is disposed on the discharge port in contact with the inclined surface of the valve seat. In addition, the fluid can flow out from the other end of the groove portion disposed on the distal end side of the valve body to the discharge port through the groove portion.

  Further, the check valve of the present invention is characterized in that at least one of the introduction port and the discharge port is disposed on the proximal end side of the valve body. That is, if the introduction port and the discharge port are arranged on the distal end side of the valve body, a strong force may be applied to the distal end of the valve body and the valve body may be bent. Since at least one of the port and the discharge port is arranged on the base end side of the valve body, it is difficult to apply a strong force to the front end side of the valve body, suppressing deformation of the valve body and maintaining normal valve opening / closing operation can do. In particular, when a valve seat having the groove is employed, a fluid flow path is secured by the groove even when the discharge port is disposed on the base end side of the valve body, so that good valve operation is maintained. Can do.

  The check valve of the present invention is characterized in that the valve body is formed of a flexible film. In other words, since this check valve uses a soft thin film valve body of a flexible film, the rigidity of the check valve is small and the force required for deformation is small. Therefore, the length of the valve body in the longitudinal direction can be shortened and the valve can be opened and closed. The required fluid volume can be reduced. Therefore, the size of the valve chamber can be further reduced, the responsiveness and stability of the valve operation can be improved, and the influence of bubbles can be further reduced.

  The check valve of the present invention includes a first housing having a top wall, a second housing having a bottom wall, a first housing and a second housing having a valve body. A projecting portion is formed on the first housing, and a recess is formed on the second housing to be fitted to the projecting portion, and a valve body is formed on the projecting portion and the recessed portion. It is characterized in that opposed surfaces parallel to each other are formed to sandwich the base end. That is, in this check valve, the base end (fulcrum) of the valve body is clarified by holding the base end of the valve body between the convex portion and the concave portion, and the valve body is positioned and the position of the valve body is determined. Misalignment can be prevented. In addition, by sandwiching the valve body between the opposing surfaces formed in the convex part and the concave part, even when the positional deviation between the concave part and the convex part occurs, the angle at which the valve body projects into the valve chamber does not change. Can be constant.

A diaphragm pump according to the present invention includes a diaphragm to which a piezoelectric element is attached, an upper housing having an upper suction flow path and an upper discharge flow path in which a pressure chamber is formed between the diaphragm and connected to the pressure chamber; A lower housing having a lower suction flow path connected to the suction flow path via a suction check valve and a lower discharge flow path connected to the upper discharge flow path via a discharge check valve; The suction-side check valve and the discharge-side check valve are the above-described check valves of the present invention, and the discharge ports are connected to the upper suction flow path and the lower discharge flow path, respectively, and the upper discharge flow path and the lower suction flow path are connected. It is characterized by the fact that each inlet is connected.
That is, in this diaphragm pump, since the check valve of the present invention is adopted for the suction side check valve and the discharge side check valve, it has high responsiveness, is less influenced by bubbles, and has a high flow rate of a small amount of liquid. It can be controlled with accuracy.

The present invention has the following effects.
That is, according to the check valve according to the present invention, the valve seat having the inclined surface is formed on the bottom wall. Therefore, efficient and highly accurate valve operation becomes possible. In addition, the valve chamber is small and hardly affected by bubbles, and the valve body is regulated by the inclined surface of the valve seat, so that the valve body is hardly deformed and high-precision operation is possible. Therefore, by adopting this check valve in the diaphragm pump, it is possible to control the flow rate of a small amount of liquid with high response and high accuracy, and it is possible to obtain a pump suitable for a fuel cell or the like.

  Hereinafter, an embodiment of a check valve according to the present invention and a diaphragm pump using the check valve will be described with reference to FIGS. 1 to 5.

  The diaphragm pump using the check valve of this embodiment is a pump for a fuel cell that supplies methanol as a fluid, for example. As shown in FIG. 1, a diaphragm 2 to which a piezoelectric element 1 is attached, a diaphragm 2, The pressure chamber 3 is formed between the upper housing 4 having the upper suction flow path 4a and the upper discharge flow path 4b connected to the pressure chamber 3, and the upper suction flow path 4a via the suction side check valve 5A. And a lower housing 6 having a lower discharge flow path 6b connected to the lower suction flow path 6a and the upper discharge flow path 4b via a discharge check valve 5B.

  The diaphragm 2 includes a resin diaphragm 2a having a part of the lower surface forming the wall of the pressure chamber 3, a metal diaphragm 2b bonded on the resin diaphragm 2a, and a piezoelectric element 1 bonded on the metal diaphragm 2b. It is composed of. The piezoelectric element 1 is a piezoelectric element (PZT), is connected to a power source (not shown), and expands and contracts when a voltage is applied.

  As shown in FIGS. 2 to 5, the suction-side check valve 5 </ b> A and the discharge-side check valve 5 </ b> B include a top wall 8 having a fluid inlet 8 a, a bottom wall 9 having a fluid outlet 9 a, and a side wall 10. And a valve body 12a disposed on the introduction port 8a, the base end of which is fixed to the side wall 10 and the tip of the valve chamber 11 is supported in a cantilevered manner. It is equipped with.

In the suction-side check valve 5 </ b> A, the bottom wall 9 is formed on the lower surface of the upper housing (second housing) 4, and the top wall 8 is formed on the upper surface of the lower housing (first housing) 6. Yes. On the other hand, in the discharge-side check valve 5B, the top wall 8 is formed on the lower surface of the upper housing (first housing) 4 and the bottom wall 9 is formed on the upper surface of the lower housing (second housing) 6. Has been.
That is, the discharge port 9a is connected to the upper suction channel 4a and the lower discharge channel 6b, respectively, and the introduction port 8a is connected to the upper discharge channel 4b and the lower suction channel 6a.

The lower suction channel 6 a is connected to a fluid supply source (not shown) via the fluid supply pipe 13. The lower discharge flow path 6 b is connected to a fluid supply destination (not shown) via the fluid discharge pipe 14.
The valve body 12a is formed in a tongue-like cantilever shape by punching the film body 12 sandwiched between the upper housing 4 and the lower housing 6 with a mold. The film body 12 and the valve body 12a are formed of a flexible film such as PP (polypropylene). The upper housing 4 and the lower housing 6 are joined by laser welding the hatched region R shown in FIG. 3 with the film body 12 being sandwiched. 4 and 5 show the valve body 12a incorporated in the upper housing 4 and the lower housing 6, and the valve body 12a in this embodiment is not subjected to processing such as embossing. It is a flat member as shown in FIG.

The bottom wall 9 has a flat surface 9b1 that is substantially parallel to the top wall 8 at a predetermined interval when facing the top wall 8, and a surface that continues from the flat surface 9b1 and extends from the proximal end to the distal end along the valve body 12a. A valve seat 9b having an inclined surface 9b2 that is inclined so as to be gradually separated from the top wall 8 is formed.
The inclined surface 9b2 of the valve seat 9b is formed with a groove portion 9c having one end connected to the discharge port 9a and the other end extended from the tip of the valve body 12a. The valve seat 9b is formed wider than the valve body 12a and longer in the longitudinal direction so that the entire valve body 12a can be supported.
The introduction port 8a and the discharge port 9a are arranged on the base end side of the valve body 12a, and a facing surface P2 formed in a lower concave portion 16b and an upper concave portion 17a, which will be described later, continues from the flat surface 9b1. Is provided.

On the lower surface of the upper housing 4 are an upper convex portion 16a having a V-shaped cross section disposed on the discharge side check valve 5B side, and an upper concave portion having an inverted V cross section disposed on the suction side check valve 5A side. 17a is formed. On the other hand, on the upper surface of the lower housing 6, a lower concave portion 16 b having a V-shaped cross section which is disposed on the discharge side check valve 5 B side and fits in correspondence with the upper convex portion 16 a and on the suction side check valve 5 A side. A lower convex portion 17b having an inverted V-shaped cross section that is arranged and fits corresponding to the upper concave portion 17a is formed.
The upper convex portion 16a, the lower concave portion 16b, the upper concave portion 17a, and the lower convex portion 17b are provided so as to extend wider than the valve body 12a in a direction orthogonal to the longitudinal direction of the valve body 12a.

  Opposing surfaces P1 and P2 that are parallel to each other and sandwich the proximal end of the valve body 12a are formed on the upper convex portion 16a and the lower concave portion 16b that are fitted to each other. Similarly, the upper concave portion 17a and the lower convex portion 17b are also formed with mutually parallel facing surfaces P1 and P2 that sandwich the proximal end of the valve body 12a. The opposed surfaces P1 and P2 are formed to be inclined with respect to the bottom wall 8 so as to form a predetermined angle.

  In this way, the base end of the valve body 12a is sandwiched between the upper convex portion 16a and the lower concave portion 16b, and between the upper concave portion 17a and the lower convex portion 17b, so that the base end (fulcrum q) of the valve body 12a is It becomes clear, the positioning of the valve body 12a can be performed, and the displacement of the valve body 12a can be prevented. Further, since the opposing surfaces P1 and P2 are formed to be inclined with respect to the bottom wall 8 so as to form a predetermined angle, the opposing surfaces P1 and P2 can be disposed so as to press the valve body 12a against the introduction port 8a in the closed state. it can. Even if the valve body 12a expands or contracts due to swelling or temperature change due to methanol, the valve body 12a is supported in a cantilever shape and is sandwiched between the convex portion and the concave portion so that the fulcrum is clear. Therefore, even in that case, highly accurate valve operation can be maintained.

Further, the upper convex portion 16a and the lower concave portion 16b, and the upper convex portion 16a and the lower convex portion 17b are sandwiched by opposing valve surfaces P1 and P2 formed on the upper concave portion 17a and the lower convex portion 17b. Even when a positional deviation with respect to the lower concave portion 16b or a positional deviation between the upper concave portion 17a and the lower convex portion 17b occurs, the angle at which the valve body 12a projects into the valve chamber 11 can be made constant.
That is, when the valve body 12a is sandwiched between the concave and convex portions having curvature, the angle of the surface that sandwiches the base end of the valve body 12a changes if there is a deviation between the concave and convex portions during fitting. Therefore, there is an inconvenience that the way (protrusion angle) of the valve body 12a protruding into the valve chamber 11 changes. However, in the case of the present embodiment, since the parallel surfaces are sandwiched, even when an assembly displacement or the like occurs, the angles of the opposing surfaces P1 and P2 that sandwich the base end of the valve body 12a are constant, and at a predetermined angle. The valve body 12a protruding into the valve chamber 11 can be obtained with high accuracy.

  Next, operations of the diaphragm pump and the check valve will be described below with reference to FIGS.

The operation of the entire diaphragm pump will be described. First, by applying a voltage so that the piezoelectric element 1 expands and contracts, the entire diaphragm 2 performs a bending motion that vibrates vertically.
When the fluid in the pressure chamber 3 is pressurized by the bending movement of the diaphragm 2, the fluid in the pressure chamber 3 flows through the upper discharge channel 4 b, the discharge-side check valve 5 B, and the lower discharge channel 6 b. 14 is discharged. At this time, in the suction side check valve 5 </ b> A, the valve body 12 a blocks the introduction port 8 a and prevents the fluid from flowing back to the fluid supply pipe 13.

  Next, when the pressure chamber 3 is depressurized by the bending movement of the diaphragm 2, the pressure chamber 3 is passed through the fluid supply pipe 13, the lower suction flow path 6a, the suction side check valve 5A, and the upper suction flow path 4a. Fluid is inhaled. At this time, in the discharge side check valve 5 </ b> B, the valve body 12 a blocks the introduction port 8 a and prevents the fluid from flowing back to the fluid discharge pipe 14. That is, the fluid can be sent out through the suction side check valve 5A and the discharge side check valve 5B that prevent backflow by repeating the bending motion of the diaphragm 2.

In the suction side check valve 5A and the discharge side check valve 5B, when the fluid flows into the valve chamber 11, that is, the opening operation is performed as follows.
When the fluid enters the valve chamber 11 from the lower suction flow path 6a or the upper discharge flow path 4b through the introduction port 8a, the valve body 12a that has blocked the introduction port 8a is pushed up by the fluid. At this time, the valve body 12a is regulated by the valve seat 9b having the inclined surface 9b2 to ensure a certain flow path in the valve chamber 11. The fluid that has flowed into the valve chamber 11 flows from the proximal end side of the valve body 12a to the distal end side, and flows into the groove portion 9c from one end of the groove portion 9c that opens to the distal end side of the valve body 12a. Further, the fluid is discharged from the discharge port 9a to the upper suction flow path 4a or the lower discharge flow path 6b through the groove 9c.

That is, even if the valve body 12a is in contact with the valve seat 9b, the fluid can flow out to the discharge port 9a through the groove 9c. Further, since the introduction port 8a and the discharge port 9a are arranged on the proximal end side of the valve body 12a, it is difficult for a strong force of fluid to be applied to the distal end side of the valve body 12a, and the deformation of the valve body 12a is suppressed to be normal. The open / close operation of the valve can be maintained. In addition, although the same effect is acquired by arrange | positioning at least one of the inlet 8a and the discharge port 9a to the base end side of the valve body 12a, both of the inlet 8a and the discharge port 9a like this embodiment are acquired. The above-mentioned effect can be obtained more efficiently by arranging the valve on the base end side of the valve body 12a.
On the other hand, when the fluid flows backward from the discharge port 9a and flows into the valve chamber 11, the valve body 12a restricted by the valve seat 9b returns to its original state and closes by closing the introduction port 8a. The operation is performed and backflow can be prevented.

  Thus, in this embodiment, since the valve seat 9b having the inclined surface 9b2 is formed on the bottom wall 9, the cantilever-shaped valve body 12a moves between the top wall 8 and the valve seat 9b. As a result, when the valve is opened and closed, the valve seat 9b having the inclined surface 9b2 is restricted and the amount of movement of the valve body 12a is reduced, and the response time from opening to closing is shortened. Further, since the movement amount is restricted to a small amount, the valve chamber 11 can be small and hardly affected by bubbles. Furthermore, even if a soft valve body 12a made of a flexible film is used, the valve body 12a is hardly deformed because it is regulated by the inclined surface 9b2 of the valve seat 9b. The valve seat 9b is provided with a flat surface 9b1 on the base end side of the valve body 12a to restrict the movement of the base end (fulcrum q) of the valve body 12a when bent, and excessively applied to the base end (fulcrum q). Plastic deformation due to stress is prevented. In this embodiment, the flat surface 9b1 is provided on the valve seat 9b. However, depending on the angle of the inclined surface 9b2 and the material of the valve body 12a, the valve seat is continuously formed from the facing surface P2 between the lower concave portion 16b and the upper concave portion 17a. The inclined surface 9b2 may be formed from the base end of 9b.

  Further, since the flexible thin film valve element 12a is used, the rigidity required is little and the force required for deformation is small. Therefore, the length of the valve element 12a in the longitudinal direction can be shortened, and the fluid required for opening and closing The volume can be reduced. Therefore, the size of the valve chamber 11 can be further reduced, and the responsiveness and stability of the valve operation can be improved and the influence of bubbles can be further reduced.

The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the present invention, the check valve and the diaphragm pump using the check valve are employed as the fuel supply pump for the fuel cell. However, the check valve and the pump using the check valve may be applied to other uses. For example, the present invention may be applied to a dilution water circulation pump for a fuel cell, a medical pump for controlling a minute flow rate of a chemical solution, or an analysis pump.

It is sectional drawing which shows the diaphragm pump of one Embodiment which concerns on this invention. In one Embodiment which concerns on this invention, it is sectional drawing which shows a non-return valve, and exploded sectional drawing. In one Embodiment which concerns on this invention, it is a top view of the non-return valve which shows a valve chamber part and a laser welding area | region in a see-through | perspective state. In one embodiment concerning the present invention, it is an exploded perspective view showing a check valve. In one Embodiment which concerns on this invention, it is a disassembled perspective view of the principal part which shows the valve chamber part of a non-return valve.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Piezoelectric element, 2 ... Diaphragm, 3 ... Pressure chamber, 4 ... Upper housing | casing (1st housing | casing, 2nd housing | casing), 4a ... Upper suction flow path, 4b ... Upper discharge flow path, 5A ... Suction Side check valve, 5B ... discharge side check valve, 6 ... lower casing (first casing, second casing), 6a ... lower suction flow path, 6b ... lower discharge flow path, 8a ... introduction port 8 ... Top wall, 9 ... Bottom wall, 9a ... Discharge port, 9b ... Valve seat, 9c ... Groove, 10 ... Side wall, 11 ... Valve chamber, 12 ... Film body, 12a ... Valve body, 16a ... Top convex part, 16b ... Lower concave portion, 17a ... Upper concave portion, 17b ... Lower convex portion

Claims (6)

A valve chamber formed by a top wall having a fluid inlet, a bottom wall having a fluid outlet, and a side wall;
A valve body that is fixed to the side wall in the valve chamber and has a distal end that is a free end and is supported in a cantilevered manner and disposed on the introduction port, and
The check valve according to claim 1, wherein a valve seat having an inclined surface is formed on the bottom wall so as to be gradually separated from the top wall from the proximal end toward the distal end along the valve body.   2. The check valve according to claim 1, wherein the valve seat has a groove portion having one end connected to the discharge port and the other end extended from the tip of the valve body. .   The check valve according to claim 1, wherein at least one of the introduction port and the discharge port is disposed on a proximal end side of the valve body.   The check valve according to claim 1 or 2, wherein the valve body is formed of a flexible film. A first housing having the top wall;
A second housing having the bottom wall;
A film body having the valve body and sandwiched between the first housing and the second housing,
A convex portion is formed on the first casing, and a concave portion that fits the convex portion is formed on the second casing.
3. The check valve according to claim 1, wherein opposing surfaces that are parallel to each other and sandwich a base end of the valve body are formed in the convex portion and the concave portion. A diaphragm with a piezoelectric element attached;
An upper housing having an upper suction flow path and an upper discharge flow path formed with a pressure chamber between the diaphragm and connected to the pressure chamber;
A lower housing having a lower suction channel connected to the upper suction channel via a suction-side check valve and a lower discharge channel connected to the upper discharge channel via a discharge-side check valve; With
2. The check valve according to claim 1, wherein the suction side check valve and the discharge side check valve are connected to the upper suction flow path and the lower discharge flow path, respectively, and the upper discharge The diaphragm pump, wherein the introduction port is connected to the flow path and the lower suction flow path, respectively.

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