Flexible tube pinch mechanism

• US 6,554,589 B2
• Filed: 12/30/1999
• Issued: 04/29/2003
• Est. Priority Date: 07/03/1997
• Status: Expired due to Fees

• Current Assignee: Precision Dispensing Systems Limited
• Original Assignee: Precision Dispensing Systems Limited
• Inventors: Grapes, Robert Donald
• Primary Examiner(s): Scherbel, David A.
• Assistant Examiner(s): KEASEL, ERIC S
• Application Number:
  US09/462,134
• Publication Number:
  US 20020047099A1
• Time in Patent Office: 1,216 Days
• Field of Search: 251/7, 417/476, 417/477.1, 417/477.9, 417/477.12
• US Class Current: 417/477.12
• CPC Class Codes: F04B 43/08 having tubular flexible members F04B43/12 takes precedence
• CPC Class Codes: F16K 7/06 by means of a screw-spindle, cam, or other mechanical means F16K7/045 takes precedence

Abstract

A pinch mechanism suitable for use as a valve or as part of a pump. The pinch mechanism comprises a housing (11) within which an elongate conduit element (12) is located. A conduit engagement member (13c) is retained within the housing (11) to be movable transverse to a longitudinal axis of the conduit element (12). The engagement member has an end portion (13d) which engages with the conduit element (12), this end portion (13d) having a cross-sectional dimension less than the lateral inner dimension of the conduit element (12), this lateral dimension being at right angles to the direction of movement of the engagement member (13c).

Claims

1. A pump comprising at least a flexible tubular element having an external surface and an internal bore which provides a flow passage through which a fluid flow can occur, a housing, at least part of the tubular element being located within the housing, and an engagement element having an engagement portion which, in use, is engageable with the external surface of a portion of the tubular element to cause said portion of the tubular element to invert into the bore of the tubular element and thereby restrict the flow passage, said portion of said tubular element being constrained within said housing to limit lateral movement thereof when the engagement portion engages with said portion of the tubular element, the engagement portion including a curved surface the diameter of which is such that in use the inversion of said portion of the tubular element can seal closed the fluid flow passage but said diameter is not greater than an external diameter of said portion of the tubular element minus four times the wall thickness of said portion of the tubular element, a non-return inlet valve associated with the tubular element to one side of said portion of the tubular element and a non-return outlet valve associated with the tubular element to the other side of said portion of the tubular element.

2. A pump as claimed in claim 1 wherein the tubular element is a flexible silicone tube.

3. A pump as claimed in claim 1 wherein the tubular element is resilient.

4. A pump as claimed in claim 1 wherein the engagement portion is elongate having a longitudinal axis parallel to the longitudinal axis of the tubular element.

5. A pump as claimed in claim 1, wherein said portion of the tubular element has a uniform wall thickness.

6. A pump as claimed in claim 1 further including a mover device for moving the engagement element.

7. A pump as claimed in claim 6 wherein the mover device is a piston mounted for reciprocating movement in a piston housing and further includes pressure control means for controlling a pressure to the piston.

8. A pump as claimed in claim 7 wherein the pressure control means includes a solenoid valve coupling the piston housing to a pressure source.

9. A pump as claimed in claim 1 wherein the housing includes a receiving chamber in which said tubular element is located.

10. A pump as claimed in claim 9 wherein the receiving chamber is configured to restrain the tubular element against lateral bulging.

11. A pump as claimed in claim 9 wherein the receiving chamber is a tunnel having a cross-sectional shape greater than an external cross-sectional shape of the tubular element.

12. A pinch mechanism as claimed in claim 11 wherein the housing has a passageway in which said engagement portion is slidingly engaged.

13. A pump comprising a flexible tubular element which provides a flow passage through which a fluid flow can occur, a housing, at least part of the tubular element being located within the housing, and an engagement element having an engagement portion which, in use, is engageable with a portion of the tubular element to deform the tubular element and thereby restrict the flow passage, said portion of said tubular element being constrained within said housing to limit lateral movement thereof when the engagement portion engages with the tubular element, the engagement portion including a curved surface the diameter of which is equal to an external diameter of said portion of the tubular element minus four times the wall thickness of said portion of the tubular element, a non-return inlet valve associated with the tubular element to one side of said portion of the tubular element and a non-return outlet valve associated with the tubular element to the other side of said portion of the tubular element.

14. A pump as claimed in claim 13 wherein the tubular element is located with a pump body which forms the conduit housing.

15. A pump as claimed in claim 13, wherein said portion of the tubular element has a uniform wall thickness.