Patent ID: 6554589
Filing Date: 2003-04-29
Classification: F04B,F16K

Abstract:
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.