Fluid actuated valve

Claim 1

A multi-port diaphragm-sealed valve capable of operating at elevated temperatures comprising: an end cap having upper and lower surfaces and a plurality of spaced-apart passageways extending through the upper and lower surfaces to provide ports for said valve; a plunger housing secured to said end cap, said plunger housing having upper and lower surfaces and a plurality of spaced-apart passageways extending through the upper and lower surfaces of said plunger housing and being positioned such that each said passageway of said plunger housing will be positioned between a different pair of the passageways of said plunger housing; a diaphragm positioned between the lower surface of said end cap and the upper surface of said plunger housing and extending over the open ends of the passageways of both said end cap and said plunger housing; a plurality of plunger means each being positioned in and extending through a respective one of the passageways of said plunger housing such that actuating means on the lower surface of the plunger housing can force each said plunger means upward so that it causes the diaphragm to block off communication between the respective surrounding pair of passageways in said end cap; means for allowing communication between adjacent pairs of passageways of said end cap when the respective plunger means are not forcing the diaphragm to block off communication between said pairs of passageways; a piston housing in sealing engagement with the lower surface of said plunger housing, said piston housing comprising a tubular sidewall; a first piston means having an opening extending axially therethrough, said first piston being positioned in said piston housing adjacent the lower surface of the plunger housing for reciprocal movement along the central axis of the piston housing in sealing engagement with the inner surface of said tubular sidewall, with the sealing engagement being provided by a spring-loaded seal comprising a ring of heat resistant polymeric material, said spring-loaded seal being in gripping engagement with the periphery of said piston in a channel extending around the periphery of said first piston, wherein the one edge of the channel extends outwardly farther than the other edge of the channel and the edge that extends outwardly the least tapers inwardly away from the channel in such a manner as to permit the spring-loaded seal to be readily snapped into said channel, and wherein the upper surface of said first piston has a configuration such that a first chamber is formed between the outer portions thereof and the lower surface of said plunger housing, and such that when said first piston is in its upper position it will force a first set of said plunger means to force the diaphragm against the end cap to block off communication between the pair of passageways in the end cap surrounding each plunger means of that first set; a second piston means being positioned in said piston housing below said first piston means for reciprocal movement along the central axis of the piston housing in sealing engagement with the inner surface of said tubular sidewall, with the sealing engagement being provided by a spring-loaded seal comprising a ring of heat resistant polymeric material, said spring-loaded seal being in gripping engagement with the periphery of said second piston in a channel extending around the periphery of said second piston wherein one edge of the channel extends outwardly further than the other edge of the channel and the edge that extends outwardly the least tapers inwardly away from the channel in such a manner as to permit the spring-loaded seal to be readily snapped in said channel, said second piston means containing a projecting portion which extends upwardly from the upper face of said second piston through the opening in said first piston for reciprocal movement in said opening in sealing engagement with said first piston, said sealing engagement being provided by a spring-loaded seal comprising a ring of heat resistant polymeric material, said spring-loaded seal being in gripping engagement with the periphery of said projecting portion in a channel extending around said projecting portion, wherein at least the upper portion of the projecting portion can be separated to allow said sealing ring to be readily placed in said channel of said projecting portion, and wherein the projecting portion is of such length and its upper surface of such configuration that when the second piston is in its uppermost position it will force a second set of said plunger means to force the diaphragm against the end cap to block off communication between the pair of passageways in the end cap surrounding each plunger of that second set, and wherein the lower surface of said first piston and the upper surface of said second piston are such that even when the second piston is in its uppermost position there is a gap between the outer portions thereof so as to define a second chamber; and wherein said second piston means includes a securement means for securing the separable portion of the projecting portion to said second piston; first spring means positioned between the lower surface of said plunger housing and said first piston means to urge said first piston means away from said plunger housing; second spring means positioned beneath the lower surface of said second piston means for urging said second piston means toward said plunger housing; spring securement means for securing said second spring means so that said second spring means will urge said second piston means toward said plunger housing; a fluid passageway extending through said piston housing into said second chamber, through which fluid can be passed to cause said first and second pistons to move relative to each other.