Valve for the interception and regulation of flow with a fixed tubular sealing element

Claim 1

A valve for controlling the flow of a fluid, said valve comprising: a hollow body internally subdivided by a baffle member into first and second chambers, said baffle member including a tubular extension which is perforated by a plurality of openings and which extends into said second chamber; an inlet in said body through which said fluid may enter said first chamber and an outlet in said body through which said fluid may exit from said second chamber; an open ended flexible tubular sealing element surrounded by said tubular extension and extending between said first and second chambers; first and second closure elements arranged respectively in said first and second chambers to close the ends of said tubular sealing element and to cooperate therewith in defining a third chamber interposed between said first and second chambers; a first port in said first closure element through which a portion of the fluid in said first chamber may flow into said third chamber, and a second port in said second closure element through which the said portion of fluid may flow from said third chamber into said second chamber; and regulator means for varying the fluid pressure in said third chamber by controlling the flow of fluid through said second port, whereupon when the fluid pressure in said first and third chambers is equalized, said flexible sealing element is caused to expand outwardly against said tubular extension to block said openings and prevent fluid flow therethrough from said first chamber to said second chamber, and when the fluid pressure in said third chamber is lowered beneath that in said first chamber, said flexible tubular sealing element is caused to collapse inwardly away from said tubular extension, thereby allowing fluid flow from said first chamber through said openings to said second chamber.