Device for delivering liquid at a stable flow rate

Patent metadata

Field	Value
Publication number	US-9828989-B2
Application number	US-201414572112-A
Country	US
Kind code	B2
Filing date	Dec 16, 2014
Priority date	Jun 22, 2012
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A liquid delivery device includes a constant flow valve, a pump and channels. A medicinal solution bag is connected to the liquid delivery device. The pump has a suction aperture, a discharge aperture and check valves. The constant flow valve includes a valve casing and a diaphragm that partitions the interior of the valve casing to form a first valve chamber and a second valve chamber. A first opening, a second opening, and a third opening are provided in the valve casing. A conical spring arranged between and in contact with a top plate and the diaphragm is provided in the second valve chamber. The spring applies a pressure towards an O-ring side to a second main surface of the diaphragm.

First claim

The invention claimed is:

1. A liquid delivery device comprising:
a pump having a suction aperture and a discharge aperture;
a liquid consumption unit; and
a valve including:
a bottom plate with a first opening communicatively coupled to the discharge aperture, such that a liquid from the discharge aperture flows into the valve via the first opening, and a second opening communicatively coupled to the liquid consumption unit, such that the liquid flows out from the valve via the second opening to the liquid consumption unit;
a valve seat disposed around a periphery of the first opening or the second opening;
a top plate with a third opening in fluid communication with air outside the liquid delivery device;
a diaphragm that is disposed between the bottom plate and the top plate and that includes a first main surface that faces the bottom plate and a second main surface that faces the top plate, such that the diaphragm and the bottom plate of the valve form a first valve chamber and the top plate and the diaphragm form a second valve chamber; and
a pressure-applying member disposed between the top plate and the diaphragm to apply pressure on the second main surface of the diaphragm,

wherein:
a region of the first main surface of the diaphragm in communication with the first opening has an area S P ,
the second main surface of the diaphragm has an area S S ,
the pump has a discharge pressure P 1 when a discharge flow rate of the pump is zero,
a pressure P S is applied to the second main surface of the diaphragm by the pressure-applying member,
a pressure P O is applied to a region of the first main surface of the diaphragm that is continuous with the second opening, and
wherein 1<α≦βγ−γ+1 in a range 0≦P O <P S , where α equals S S /S P (α>1), β equals P 1 /P S (β>1), and γ % is a flow rate accuracy.

2. The liquid delivery device according to claim 1 , wherein the flow rate accuracy γ % is 10%.

3. The liquid delivery device according to claim 1 , wherein the pressure-applying member includes an adjustment mechanism to adjust the pressure applied to the second main surface of the diaphragm.

4. The liquid delivery device according to claim 3 , wherein the adjustment mechanism includes an elastic body and a pressing body that urges the elastic body toward the valve seat.

5. The liquid delivery device according to claim 4 , wherein the pressing body is provided in the valve and is rotatable by screwing a screw having a rotational axis in a direction orthogonal to the diaphragm.

6. The liquid delivery device according to claim 5 , wherein rotating the pressing body adjusts the pressure applied to the second main surface of the diaphragm.

7. The liquid delivery device according to claim 1 , wherein the valve seat is a protruding member that is integrated with the diaphragm.

8. The liquid delivery device according to claim 1 , wherein the valve seat is integrated with the bottom plate of the valve.

9. The liquid delivery device according to claim 1 , wherein the pressure-applying member is integrated with the diaphragm.

10. The liquid delivery device according to claim 1 , wherein the valve seat comprises an O-ring.

11. The liquid delivery device according to claim 10 , wherein the O-ring is disposed between the bottom plate and the first main surface of the diaphragm.

12. The liquid delivery device according to claim 11 , wherein the O-ring is disposed around the periphery of the second opening of the bottom plate of the valve.

13. The liquid delivery device according to claim 12 , wherein, when pressure greater than a threshold resulting from the pressure-applying member is applied to the first main surface of the diaphragm, the diaphragm separates from the O-ring such that the first opening is in fluid communication with the second opening of the bottom plate of the valve.

14. The liquid delivery device according to claim 1 , wherein the pressure-applying member is a spring and is disposed in the second valve chamber.

15. The liquid delivery device according to claim 1 , wherein the diaphragm and the bottom plate of the valve form a valve chamber between the first opening and the second opening.

16. The liquid delivery device according to claim 1 , wherein the bottom plate is flat and the first opening and the second opening are disposed adjacent to each other.

Assignees

• Murata Manufacturing Co

Inventors

• Yokoi Hiroyuki
• Higashiyama Yuzo

Classifications

• F04B43/00

  Machines, pumps, or pumping installations having flexible working members (pumps or pumping installations specially adapted for elastic fluids F04B45/00) · CPC title

• F04B53/1087

  Valve seats · CPC title

• F04B23/02

  having reservoirs · CPC title

• F04B39/102

  the members being disc valves · CPC title

• F04B53/109

  inlet and outlet valve forming one unit · CPC title