DIAPHRAGM PUMP

A diaphragm pump includes a low pressure side diaphragm forming a part of a pulsation operating chamber, a high pressure side diaphragm forming a part of a pump chamber, and a connecting portion connecting the low pressure side diaphragm and the high pressure side diaphragm. The high pressure side diaphragm operates in conjunction with the low pressure side diaphragm by being connected to the low pressure side diaphragm by the connecting portion. An area of a high pressure side operating portion of the high pressure side diaphragm is smaller than an area of a low pressure side operating portion of the low pressure side diaphragm.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-090307, filed on Jun. 2, 2022, the entire contents of which are incorporated herein by reference.

BACKGROUND

Field

The present disclosure relates to a diaphragm pump that operates by receiving a pulsating pressure in a crank chamber of an engine.

Description of the Related Art

Japanese Patent Publication No. 2010-90846 discloses an engine having a diaphragm pump. The diaphragm pump operates by receiving a pulsating pressure in a crank chamber of an engine.

SUMMARY

Disclosed herein is an example diaphragm pump that operates by receiving a pulsating pressure in a crank chamber of an engine, the diaphragm pump including: a low pressure side diaphragm forming a part of a pulsation operating chamber to which the pulsating pressure is transmitted and configured to operate by receiving the pulsating pressure; a high pressure side diaphragm forming a part of a pump chamber for supplying fuel to the engine and configured to send the fuel to the engine by operating; and a connecting portion connecting the low pressure side diaphragm and the high pressure side diaphragm to each other. The high pressure side diaphragm operates in conjunction with the low pressure side diaphragm by being connected to the low pressure side diaphragm by the connecting portion. An area of a high pressure side operating portion that is a portion of the high pressure side diaphragm which operates in conjunction with the low pressure side diaphragm is smaller than an area of a low pressure side operating portion that is a portion of the low pressure side diaphragm which operates by receiving the pulsating pressure.

In this diaphragm pump, the diaphragm (the low pressure side diaphragm) that operates by receiving the pulsating pressure in the crank chamber and the diaphragm (the high pressure side diaphragm) that sends the fuel are separately provided. The high pressure side diaphragm operates in conjunction with the low pressure side diaphragm, and the area of the high pressure side operating portion is smaller than the area of the low pressure side operating portion. In some examples, due to the difference in area between the low pressure side operating portion and the high pressure side operating portion, the high pressure side diaphragm (20) may apply a pressure higher than the pulsating pressure in the crank chamber to the fuel. The diaphragm pump may further pressurize the fuel by receiving the pulsating pressure in the crank chamber of the engine and supply the further pressurized fuel.

In some examples, the diaphragm pump has a low pressure side backup attached to the low pressure side operating portion and a high pressure side backup attached to the high pressure side operating portion. An area of the low pressure side backup is larger than an area of the high pressure side backup. Accordingly, the diaphragm pump may curb unintended deflection of the low pressure side diaphragm and the high pressure side diaphragm with the low pressure side backup and the high pressure side backup and to operate the low pressure side diaphragm and the high pressure side diaphragm.

In some examples, the low pressure side diaphragm has an annular low pressure side movable portion around the low pressure side backup. The high pressure side diaphragm has an annular high pressure side movable portion around the high pressure side backup. A width of the annular low pressure side movable portion in a radial direction is smaller than a width of the annular high pressure side movable portion in a radial direction. By reducing the width of the low pressure side movable portion, the diaphragm pump may curb the low pressure side movable portion being movable. The entire low pressure side diaphragm moves, and the high pressure side diaphragm may be operated in conjunction with the low pressure side diaphragm. Further, since the width of the high pressure side movable portion is larger than the width of the low pressure side movable portion, a stroke (a movement amount) of the high pressure side diaphragm can be ensured to be larger. Accordingly, when the high pressure side diaphragm operates in conjunction with the low pressure side diaphragm (10), the high pressure side diaphragm may be operated without being restricted in the amount of movement caused by the width of the high pressure side movable portion.

Additionally, an example diaphragm pump is disclosed herein. A diaphragm pump that operates by receiving a pulsating pressure in a crank chamber of an engine. The diaphragm pump includes a low pressure side diaphragm forming a part of a pulsation operating chamber and configured to receive the pulsating pressure, a high pressure side diaphragm forming a part of a pump chamber and configured to send fuel to the engine, and a connecting portion connecting the low pressure side diaphragm and the high pressure side diaphragm to each other. The high pressure side diaphragm operates in conjunction with the low pressure side diaphragm by being connected to the low pressure side diaphragm by the connecting portion. An area of a high pressure side operating portion of the high pressure side diaphragm which operates in conjunction with the low pressure side diaphragm is smaller than an area of a low pressure side operating portion of the low pressure side diaphragm which operates by receiving the pulsating pressure.

Additionally, an example diaphragm pump is disclosed herein. The diaphragm pump includes a first operating chamber, and a second operating chamber, a first diaphragm located in the first operating chamber and a second diaphragm located in the second operating chamber and a connecting portion connecting the first diaphragm and the second diaphragm, and configured to operate the second diaphragm to send the fuel to the engine in response to the first diaphragm receiving the pulsating pressure. The first diaphragm includes a first surface area that is configured to receive a pulsating pressure. The second diaphragm includes a second surface area in contact with fuel for an engine. The second surface area is smaller than the first surface area.

Additionally, an example diaphragm pump disclosed herein. The diaphragm pump A diaphragm pump includes a first operating chamber, a second operating chamber located adjacent to the first operating chamber, a first diaphragm located in the first operating chamber, a second diaphragm located in the second operating chamber, and a connecting portion connecting the first diaphragm and the second diaphragm, and configured to operate the second diaphragm in response to the first diaphragm receiving the pulsating pressure. The first diaphragm includes a first surface area facing away from the second operating chamber. The second diaphragm includes a second surface area facing away from the first operating chamber. The second surface area is smaller than the first surface area.

DETAILED DESCRIPTION

In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted.

As shown inFIG.1, an example diaphragm pump1functions as a fuel pump that supplies fuel to an engine2. The diaphragm pump1operates by receiving a pulsating pressure of gas in a crank chamber2aof the engine2(pressure fluctuation of gas in the crank chamber2a). Here, the diaphragm pump1is connected to the crank chamber2aof the engine2with a pipe L3. As a result, the diaphragm pump1can receive the pulsating pressure of the crank chamber2avia the pipe L3.

The diaphragm pump1sucks the fuel from the fuel tank3via a pipe L2and supplies the fuel with an increased pressure to a fuel injection device2bprovided in the engine2via a pipe L1. Further, the diaphragm pump1may have a mechanism for returning surplus fuel not supplied to the engine2of the fuel sucked from the fuel tank3to the tank. The fuel is an example of liquid.

The diaphragm pump1includes a low pressure side diaphragm10, a high pressure side diaphragm20, a connecting portion30, a main body portion40, an intake valve50, and a discharge valve60, as shown inFIG.2.

The main body portion40has therein a first operating region R10, a second operating region R20, and the like, which will be described later. The first operating region R10is an example of a first operating chamber. The second operating region R20is a second operating chamber. A volume of the operating region R20is smaller than a volume of the first operating region R10.

In some examples, the main body portion40is formed by stacking a first main body portion41, a second main body portion42, a third main body portion43, and a fourth main body portion44in that order. A gasket is disposed between the stacked members of the first main body portion41to the fourth main body portion44. The first main body portion41to the fourth main body portion44are fixed to each other by a screw or the like.

The first operating region R10is formed between the first main body portion41and the second main body portion42. The first operating region R10is a region in which the low pressure side diaphragm10operates. The general shape of the first operating region R10is a thin columnar shape whose axis is a stacking direction of the first main body portion41and the second main body portion42.

Here, a recess41ais provided in a surface of the first main body portion41on a side of the second main body portion42. Further, a recess42ais provided in a surface of the second main body portion42on a side of the first main body portion41. The recess41aand the recess42aface each other. The first operating region R10is formed by the recess41aof the first main body portion41and the recess42aof the second main body portion42.

A pulsation transmitting port S1is formed in the first main body portion41. The pipe L3(seeFIG.1) leading to the crank chamber2aof the engine2is connected to the pulsation transmitting port S1. Further, a pulsation transmitting channel L11that connects the pulsation transmitting port S1and the first operating region R10to each other is formed in the first main body portion41.

The second operating region R20is formed between the second main body portion42and the third main body portion43. The second operating region R20is a region in which the high pressure side diaphragm20operates. The general shape of the second operating region R20is a thin columnar shape whose axis is a stacking direction of the second main body portion42and the third main body portion43.

Here, a recess42bis provided in a surface of the second main body portion42on a side of the third main body portion43. A recess43ais provided in a surface of the third main body portion43on a side of the second main body portion42. The recess42band the recess43aface each other. The second operating region R20is formed by the recess42bof the second main body portion42and the recess43aof the third main body portion43.

An intake port S2and a discharge port S3are formed in the fourth main body portion44. The pipe L2(seeFIG.1) leading to the fuel tank3is connected to the intake port S2. The pipe L1leading to the fuel injection device2bof the engine2is connected to the discharge port S3.

A low pressure side diaphragm10is disposed between the first main body portion41and the second main body portion42. The low pressure side diaphragm10is an example of a first diaphragm. The low pressure side diaphragm10is located in the first operating region R10. In some examples, the low pressure side diaphragm10partitions the first operating region R10into two. One of the spaces defined by the low pressure side diaphragm10is a pulsation operating chamber R11and the other is a first back chamber R12. The pulsation operating chamber R11is the space between the low pressure side diaphragm10and the recess41aof the first main body portion41in the first operating region R10. The pulsation transmitting channel L11is connected to the pulsation operating chamber R11and transmits the pulsating pressure to the low pressure side diaphragm10.

The pulsation operating chamber R11receives the pulsating pressure. The pulsation operating chamber R11communicates with the crank chamber2avia the pulsation transmitting channel L11and the pipe L3. The pulsating pressure of the crank chamber2ais transmitted to the pulsation operating chamber R11via the pulsation transmitting channel L11and the pipe L3.

For example, two plates12are disposed between the first main body portion41and the second main body portion42. The low pressure side diaphragm10is disposed between the two plates12. Further, the plate12is provided with an opening portion12ain a portion located within the first operating region R10. The opening portion12ahas a circular shape. In some examples, a portion of the low pressure side diaphragm10in the opening portion12aof the plate12is an operating range of the low pressure side diaphragm10. Hereinafter, the portion of the low pressure side diaphragm10in the opening portion12aof the plate12is referred to as a low pressure side operating portion10a. The low pressure side operating portion10afacing the pulsation operating chamber R11is an example of a first surface area. The low pressure side operating portion10afaces away from the second operating region R20. The low pressure side operating portion10areceives the pulsating pressure.

A low pressure side backup11is attached to the low pressure side diaphragm10. The low pressure side backup11is a plate-shaped member fixed to the low pressure side operating portion10a. The low pressure side backup11supports the low pressure side diaphragm10. For example, two low pressure side backups11are provided. The low pressure side diaphragm10is sandwiched between the two low pressure side backups11. The diameter of the low pressure side backup11is smaller than the inner diameter of the opening portion12aof the plate12. One of the low pressure side backup11faces the pulsation operating chamber R11and transmits the pulsating pressure to the low pressure side operating portion10a. The low pressure side backup10is an example of a first support member.

In some examples, as shown inFIG.3, an annular gap is provided between the outer peripheral edge of the low pressure side backup11and the circular opening portion12aof the plate12in a radial direction of the circular low pressure side backup11. The corner of the outer peripheral edge of the low pressure side backup11is rounded not to damage the low pressure side diaphragm10when the low pressure side diaphragm10operates (seeFIG.2).

In this way, the low pressure side diaphragm10faces the pulsation operating chamber R11. In some examples, the low pressure side diaphragm10forms a part of the pulsation operating chamber R11to which the pulsating pressure of the crank chamber2aof the engine2is transmitted. For this reason, the low pressure side diaphragm10operates by receiving the pulsating pressure of the crank chamber2a.

As shown inFIG.2, the high pressure side diaphragm20is disposed between the second main body portion42and the third main body portion43. The high pressure side diaphragm20is an example of a second diaphragm. The high pressure side diaphragm20is located in the second operating region R20. For example, the high pressure side diaphragm20partitions the second operating region R20into two. One of the spaces defined by the high pressure side diaphragm20is a pump chamber R21and the other is a second back chamber R22. The pump chamber R21is the space between the high pressure side diaphragm20and the recess43aof the third main body portion43in the second operating region R20. The pump chamber R21receives the fuel and sends the fuel to the engine2. A volume of the pump chamber R21is smaller than a volume of the pulsation operating chamber R11.

A portion of the high pressure side diaphragm20in the second operating region R20is an operating range of the high pressure side diaphragm20. Hereinafter, the portion of the high pressure side diaphragm20in the second operating region R20is referred to as a high pressure side operating portion20a. The high pressure side operating portion20afacing the pump chamber R21is an example of a second surface area. The high pressure side operating portion20ais in contact with the fuel in the pump chamber R21. The high pressure side operating portion20afaces away from the first operating region R10. The high pressure side operating portion20ais smaller than the low pressure side operating portion10a.

A high pressure side backup21is attached to the high pressure side diaphragm20. The high pressure side backup21is a plate-shaped member fixed to the high pressure side operating portion20a. The high pressure side backup21supports the high pressure side diaphragm21. The high pressure side backup20is an example of a second support member. For example, two high pressure side backups21are provided. The high pressure side diaphragm20is sandwiched between the two high pressure side backups21. The diameter of the high pressure side backup21is smaller than the diameter of the opening edge of each of the recess42bof the second main body portion42and the recess43aof the third main body portion43. One of the high pressure side backup21faces the pump chamber R21and located between the high pressure side operating portion20aand the fuel in the pump chamber R21.

In some examples, as shown inFIG.4, an annular gap is provided between the outer peripheral edge of the high pressure side backup21and the opening edge of the recess43aof the third main body portion43in a radial direction of the circular high pressure side backup21. The outer peripheral edge of the high pressure side backup21is curved away from the high pressure side diaphragm20not to damage the high pressure side diaphragm20when the high pressure side diaphragm20operates (seeFIG.2). A first contact surface area that fixes the low pressure side backup11to the low pressure side diaphragm10is larger than a second contact surface area that fixes the high pressure side backup21to the high pressure side diaphragm20.

In this way, the high pressure side diaphragm20faces the pump chamber R21. The pump chamber R21produces pressurized fuel for supply to the fuel injection device2bof the engine2, as will be described later. In some examples, the high pressure side diaphragm20forms a part of the pump chamber R21from which the fuel is supplied to the fuel injection device2bof the engine2. The high pressure side diaphragm20operates in conjunction with the low pressure side diaphragm10to suck the fuel from the fuel tank3and to send the fuel to the fuel injection device2bof the engine2.

As shown inFIG.2, an intake channel L12that connects the intake port S2and the pump chamber R21to each other is formed in the main body portion40. The intake channel L12is fluidly coupled with the pump chamber R21. In some examples, the intake channel L12guides the fuel guided from the fuel tank3to the intake port S2via the pipe L2to the pump chamber R21. For example, the intake channel L12is formed by grooves and holes provided in the second main body portion42, the third main body portion43, and the fourth main body portion44.

Further, a discharge channel L13that connects the pump chamber R21and the discharge port S3to each other is formed in the main body portion40. The discharge channel L13is fluidly coupled with the pump chamber R21. In some examples, the discharge channel L13guides the fuel pressurized in the pump chamber R21to the discharge port S3. For example, the discharge channel L13is formed by grooves and holes provided in the second main body portion42, the third main body portion43, and the fourth main body portion44.

The second main body portion42is located between the first operating region R10and the second operating region R20. The second main body portion42is located between the low pressure side diaphragm10and the high pressure side diaphragm20. The second main body portion42is an example of wall portion. A guide hole42cpenetrates the second main body portion42.

The connecting portion30is passed through a guide hole42c. The connecting portion30is movable in a penetrating direction of the guide hole42c. The connecting portion30connects the low pressure side diaphragm10and the high pressure side diaphragm20to each other. The connecting portion30operates the high pressure side diaphragm20to send the fuel to the engine2in response to the low pressure side diaphragm10receiving the pulsating pressure.

The connecting portion30has a first end portion30aand a second end portion30b. The first end portion30ais attached to the low pressure side diaphragm10. The second end portion30bis attached to the high pressure side diaphragm20. For example, the first end portion is fixed to a center of the low pressure side diaphragm10, and the second end portion30bis fixed to a center of the high pressure side diaphragm20.

The connecting portion30includes a sleeve31and a rivet32. The sleeve31is passed through the guide hole42c. The rivet32is passed through an inside of the sleeve31and fix the sleeve31to the low pressure side diaphragm10and the high pressure side diaphragm20. The sleeve31is disposed between the low pressure side diaphragm10and the high pressure side diaphragm20. Here, the sleeve31is disposed between the low pressure side backup11provided on a surface of the low pressure side diaphragm10on a side of the second main body portion42, and a high pressure side backup21provided on a surface of the high pressure side diaphragm20on a side of the second main body portion42. The sleeve31is fixed to the low pressure side diaphragm via the low pressure side backup11and fixed to the high pressure side diaphragm20via the high pressure side backup21.

The rivet32fixes the low pressure side diaphragm10and the high pressure side diaphragm20to the sleeve31in a state where the sleeve31is sandwiched between the low pressure side diaphragm10and the high pressure side diaphragm20. Here, the rivet32collectively fixes the two low pressure side backups11and the low pressure side diaphragm10and the two high pressure side backups21and the high pressure side diaphragm20to the sleeve31. As a result, the high pressure side diaphragm20operates in conjunction with the low pressure side diaphragm10. In some examples, the high pressure side diaphragm operates in conjunction with the low pressure side diaphragm10by being connected to the low pressure side diaphragm10by the connecting portion30, wherein the low pressure side diaphragm operates with the pulsating pressure in the crank chamber2aof the engine2.

The guide hole42cprovided in the second main body portion42has a cylindrical shape extending in a direction in which the low pressure side diaphragm10and the high pressure side diaphragm20are arranged. The outer peripheral surface of the sleeve31of the connecting portion30is in slidable contact with the inner peripheral surface of the guide hole42cof the second main body portion42. In some examples, the movement direction of the sleeve31of the connecting portion30is guided by the guide hole42cof the second main body portion42. As a result, the operating directions of the low pressure side diaphragm10and the high pressure side diaphragm20are defined.

Here, in the high pressure side diaphragm20, a portion of the high pressure side operating portion20adescribed above operates in conjunction with the low pressure side diaphragm10. In the low pressure side diaphragm10, a portion of the low pressure side operating portion10adescribed above operates by receiving the pulsating pressure in the crank chamber2aof the engine2. For example, an area of the high pressure side operating portion20aof the high pressure side diaphragm20is smaller than an area of the low pressure side operating portion10aof the low pressure side diaphragm10.

Further, an area of the low pressure side backup11is larger than an area of the high pressure side backup21. Here, the area of the low pressure side backup11is an area of the low pressure side backup11located in the pulsation operating chamber R11of the two low pressure side backups11. Further, the area of the low pressure side backup11here is an area of a surface facing the inside of the pulsation operating chamber R11(a surface facing a side of the recess41aof the first main body portion41) of the outer surface of the low pressure side backup11located in the pulsation operating chamber R11. Similarly, the area of the high pressure side backup21is an area of the high pressure side backup21located in the pump chamber R21of the two high pressure side backups21. Further, the area of the high pressure side backup21here is an area of a surface facing the inside of the pump chamber R21(a surface facing a side of the recess43aof the third main body portion43) of the outer surface of the pump chamber R21located in the high pressure side backup21.

As described above, the low pressure side diaphragm10is sandwiched between the two low pressure side backups11. For this reason, a movable portion of the low pressure side diaphragm10is a portion between the outer peripheral edge of the low pressure side backup11and the inner peripheral edge of the plate12. In some examples, the low pressure side diaphragm10has an annular low pressure side movable portion10baround the low pressure side backup11(seeFIG.3). The annular low pressure side movable portion10bis an example of a movable portion or a first annular movable portion.

Similarly, the high pressure side diaphragm20is sandwiched between the two high pressure side backups21. For this reason, a movable portion of the high pressure side diaphragm20is a portion between the outer peripheral edge of the high pressure side backup21and the opening edge of the recess42aof second main body portion42or the like. In some examples, the high pressure side diaphragm20has an annular high pressure side movable portion20baround the high pressure side backup21. The annular high pressure side movable portion20bis an example of a movable portion or a second annular movable portion.

In some examples, the annular low pressure side movable portion10bhas a width10A in a radial direction with respect to the low pressure side diaphragm10(FIG.3). The annular high pressure side movable portion20bhas a width20A in a radial direction with respect to the low pressure side diaphragm20(FIG.4). The width10A is smaller than the width20A.

The intake valve50is provided in the intake channel L12. The discharge valve60is provided in the discharge channel L13. The intake valve50and the discharge valve60are opened and closed such that when the high pressure side diaphragm20operates, the fuel is sent from the intake channel L12to the pump chamber R21and the fuel is discharged from the pump chamber R21via the discharge channel L13. In some examples, the intake valve50and the discharge valve60are opened and closed such that a pump mechanism is realized through the operation of the high pressure side diaphragm20.

For example, the intake valve50includes a valve body51and a spring52. The valve body51may be configured to selectively open or closes the intake channel L12. Here, the valve body51may be configured to selectively open or close an opening portion of a flow channel portion provided in the third main body portion43of the members forming the intake channel L12. The spring52biases the valve body51such that the intake channel L12is closed. The intake valve50allows circulation of the fuel only in a direction from the intake port S2to the pump chamber R21in the intake channel L12and cuts off circulation of the fuel in a direction opposite to the above-described direction by opening and closing the valve body51.

The discharge valve60has a valve body61and a spring62. The valve body61may be configured to selectively open or close the discharge channel L13. Here, the valve body61may be configured to selectively open or close an opening portion of a flow channel portion provided in the third main body portion43of the members forming the discharge channel L13. The spring62biases the valve body61such that the discharge channel L13is closed. The discharge valve60allows circulation of the fuel only in a direction from the pump chamber R21to the discharge port S3in the discharge channel L13and cuts off circulation of the fuel in a direction opposite to the above-described direction by opening and closing the valve body61.

As described above, in this diaphragm pump1, the low pressure side diaphragm10that operates by receiving the pulsating pressure in the crank chamber2aand the high pressure side diaphragm20that sends the fuel are separately provided. The high pressure side diaphragm20operates in conjunction with the low pressure side diaphragm10, and the area of the high pressure side operating portion20ais smaller than the area of the low pressure side operating portion10a. In some examples, due to the difference in area between the low pressure side operating portion10aand the high pressure side operating portion20a, the high pressure side diaphragm20can apply a pressure higher than the pulsating pressure in the crank chamber2ato the fuel. In this way, the diaphragm pump1can further pressurize the fuel by receiving the pulsating pressure in the crank chamber2aof the engine2and supply the further pressurized fuel.

In the diaphragm pump1, the area of the low pressure side backup11attached to the low pressure side diaphragm10is larger than the area of the high pressure side backup21attached to the high pressure side diaphragm20. The diaphragm pump1may curb unintended deflection of the low pressure side diaphragm10and the high pressure side diaphragm20with the low pressure side backup11and the high pressure side backup21and to operate the low pressure side diaphragm10and the high pressure side diaphragm20.

The low pressure side diaphragm10has the annular low pressure side movable portion10baround the low pressure side backup11. The high pressure side diaphragm20has the annular high pressure side movable portion20baround the high pressure side backup21. Further, the width A10of the annular low pressure side movable portion10bin the radial direction is smaller than the width A20of the annular high pressure side movable portion20bin the radial direction.

Here, in a case where the width of the low pressure side movable portion10bis increased, it is conceivable that only this low pressure side movable portion10bwill move by receiving the pulsating pressure in the crank chamber2a. Therefore, by reducing the width of the low pressure side movable portion10bmay curb only the low pressure side movable portion10bbeing movable. As a result, the entire low pressure side diaphragm10moves, and the high pressure side diaphragm20can be operated in conjunction with the low pressure side diaphragm10.

Further, since the width of the high pressure side movable portion is larger than the width of the low pressure side movable portion10b, a stroke (a movement amount) of the high pressure side diaphragm20can be ensured to be larger. As a result, when the high pressure side diaphragm20operates in conjunction with the low pressure side diaphragm10, the high pressure side diaphragm20can be operated without being restricted in the amount of movement caused by the width of the high pressure side movable portion20b.

It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail. For example, the shapes of the pulsation transmitting channel L11, the intake channel L12, and the discharge channel L13provided in the main body portion40, the configurations of the intake valve50and the discharge valve60, and the like are not limited to those shown inFIG.2. In addition, the configuration of the connecting portion30is not limited to the configuration described above as long as the low pressure side diaphragm and the high pressure side diaphragm20can be connected to each other.