LIQUID FEED PUMP AND FLOW CONTROL DEVICE

• US 20130343909A1
• Filed: 08/28/2013
• Published: 12/26/2013
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: CKD Corporation
• Original Assignee: CKD Corporation
• Inventors: NITTA, Shinichi
• Granted Patent: US 8,888,471 B2
• Time in Patent Office: Days
• US Class Current: 417/43
• CPC Class Codes: F04B 43/046 with piezoelectric drive

Abstract

A liquid feed pump includes a pump housing, a diaphragm forming a pump chamber together with the recessed portion surface and partitioning the pump chamber from the hole, a reciprocating member reciprocatably inserted into the hole and reciprocating to press the diaphragm to deform, a driving member displacing the reciprocating member periodically in a direction of reciprocation, a seal portion sandwiching the diaphragm to seal the diaphragm in a position around an outer peripheral side of the recessed portion surface, a diaphragm receiving surface provided between the seal portion and the opening portion, and its contact area contacting the diaphragm decreases in response to an increase in the displacement of the reciprocating member to the recessed portion surface side and increases in response to an increase in the internal pressure of the pump chamber.

Claims

1. A liquid feed pump comprising:

a pump housing formed with a columnar hole, a recessed portion surface opposing an opening portion of the hole and a peripheral portion of the hole, an intake passage having an intake port in the recessed portion surface, and a discharge passage having a discharge port in the recessed portion surface;

a diaphragm that forms a pump chamber together with the recessed portion surface and partitions the pump chamber from the columnar hole;

a reciprocating member reciprocatably inserted into the hole, and configured to reciprocate to press the diaphragm such that the diaphragm deforms;

a driving member configured to displace the reciprocating member periodically in a direction of reciprocation of the reciprocating member and vary a stroke of the reciprocation;

a seal portion configured to sandwich the diaphragm to seal the diaphragm in a position around an outer peripheral side of the recessed portion surface; and

a diaphragm receiving surface provided between the seal portion and the opening portion, the diaphragm receiving surface of which a contact area contacting the diaphragm varies in accordance with a displacement and an internal pressure of the pump chamber,

wherein the contact area decreases in response to an increase in the displacement of the reciprocating member to the recessed portion surface side and increases in response to an increase in the internal pressure of the pump chamber.

2. The liquid feed pump according to claim 1, wherein the seal portion is configured to sandwich the diaphragm between a seal pressurization surface, which is continuously connected to the recessed portion surface, and a seal receiving surface, which is continuously connected to the diaphragm receiving surface, and

the seal receiving surface is connected smoothly to the diaphragm receiving surface.

3. The liquid feed pump according to claim 2, wherein the seal receiving surface is an annular flat surface.

4. The liquid feed pump according to claim 3, wherein the diaphragm receiving surface is formed as an annular flat surface, and the opening portion is formed to be concentric with the diaphragm receiving surface.

5. The liquid feed pump according to claim 2, wherein the diaphragm receiving surface is formed to be coplanar with the seal receiving surface.

6. The liquid feed pump according to claim 1, wherein the reciprocating member includes an end portion having a projecting curved surface as a contact surface contacting the diaphragm.

7. The liquid feed pump according to claim 1, wherein the recessed portion surface includes a recessed curved surface, which is recessed in a direction to fit into a shape of the diaphragm when the diaphragm is driven in a discharge direction, and

the recessed curved surface includes an intake side groove portion configured to extend in a central direction of the recessed curved surface from the opening portion of the intake passage to communicate with the pump chamber, and a discharge side groove portion configured to extend in the central direction of the recessed curved surface from the opening portion of the discharge passage to communicate with the pump chamber.

8. The liquid feed pump according to claim 1, wherein the driving member includes a piezoelectric actuator configured to drive the diaphragm.

9. A flow control device for controlling a liquid feed pump, comprising:

the liquid feed pump according to claim 8; and

a control unit configured to control a discharge flow rate of the liquid feed pump by adjusting a voltage applied to the piezoelectric actuator.

10. The flow control device according to claim 9, wherein the control unit is configured to apply a pulse voltage, which is a pulse-shaped voltage, to the piezoelectric actuator, and control the discharge flow rate of the liquid feed pump by adjusting a maximum value of the pulse voltage.

11. The flow control device according to claim 9, further comprising a pressure sensor configured to measure a discharge pressure of a fluid discharged from the discharge passage,

wherein the control unit is configured to restrict the stroke to be smaller than a predetermined value in accordance with the measured discharge pressure.

12. The flow control device for controlling a liquid feed pump according to claim 9, further comprising a flow rate sensor configured to measure a discharge flow rate of a fluid discharged from the discharge passage,

wherein the control unit is configured to restrict a driving period of the reciprocation to be longer than a predetermined value in accordance with the measured discharge flow rate.

13. The flow control device according to claim 9, further comprising a flow rate sensor configured to measure a discharge flow rate of a fluid discharged from the discharge passage,

wherein the control unit is configured to lengthen a driving period of the reciprocation in response to an increase in the measured discharge flow rate and shorten the driving period of the reciprocation in response to a reduction in the measured discharge flow rate in an operating mode.

14. The flow control device according to claim 9, wherein the liquid feed pump includes a flow rate sensor configured to measure a discharge flow rate of the liquid feed pump, and

the control unit is configured to perform flow rate control by feeding back a discharge flow rate measured at a plurality of measurement timings within respective driving periods of the reciprocation.

15. The liquid feed pump according to claim 3, wherein the diaphragm receiving surface is formed to be coplanar with the seal receiving surface.

16. The liquid feed pump according to claim 2, wherein the reciprocating member includes an end portion having a projecting curved surface as a contact surface contacting the diaphragm.

17. The liquid feed pump according to claim 2, wherein the recessed portion surface includes a recessed curved surface, which is recessed in a direction to fit into a shape of the diaphragm when the diaphragm is driven in a discharge direction, and

the recessed curved surface includes an intake side groove portion configured to extend in a central direction of the recessed curved surface from the opening portion of the intake passage to communicate with the pump chamber, and a discharge side groove portion configured to extend in the central direction of the recessed curved surface from the opening portion of the discharge passage to communicate with the pump chamber.

18. The liquid feed pump according to claim 4, wherein the diaphragm receiving surface is formed to be coplanar with the seal receiving surface.

19. The liquid feed pump according to claim 3, wherein the reciprocating member includes an end portion having a projecting curved surface as a contact surface contacting the diaphragm.

20. The liquid feed pump according to claim 3, wherein the recessed portion surface includes a recessed curved surface, which is recessed in a direction to fit into a shape of the diaphragm when the diaphragm is driven in a discharge direction, and

the recessed curved surface includes an intake side groove portion configured to extend in a central direction of the recessed curved surface from the opening portion of the intake passage to communicate with the pump chamber, and a discharge side groove portion configured to extend in the central direction of the recessed curved surface from the opening portion of the discharge passage to communicate with the pump chamber.