Sleeve valves

Claim 1

In a flow passage sleeve valve having a housing capable of being internally pressurized, and an elastomer sleeve positioned within the housing and extending longitudinally therein, said elastomer sleeve being defined by a generally constant thickness wall tapering inwardly from opposed substantially circular end portions to a narrow transversely elongate median region of greater transverse width than the circular end portions, the sleeve wall, at the median region, being internally enlarged relative to the wall thickness for the full transverse width of the sleeve to define an internal integral sealing member as an annular, inward projection forming a pair of transversely extending lips, said lips being transversely elongate across substantially the full width of said median region and integrally joined to each other at the opposed ends thereof, said median region forming an arcuate configuration at each of the joined ends of the lips to allow flexure of said lips relative to each other and engagement of the lips in sealed relationship without undue stress in said elastomer sleeve, said median region being configured to retain said lips closed in the absence of pressure both internally and externally of the elastomer sleeve, and further comprising means for imposing external pressure directly upon said lips and said sleeve to produce direct sealing engagement of said lips in a single action at external pressures equal to or greater than internal flow pressure on said sleeve.