Fluid actuated valve

Claim 1

A multi-port diaphragm-sealed valve comprising: a piston housing comprising a tubular sidewall and a base portion closing off the lower end of said tubular sidewall portion; a plunger housing in sealing engagement with said piston housing to close off the upper end of said tubular sidewall, said plunger housing having upper and lower planar faces, a plurality of spaced-apart passageways therein communicating between the upper and the lower faces of said plunger housing, and a plurality of recesses on the upper face of said plunger housing each extending from one of the passageways in said plunger housing to another of the passageways in said plunger housing; a cap in sealing engagement with the upper face of said plunger housing and covering the passageways in said plunger housing, said cap having upper and lower planar faces and a plurality of spaced-apart passageways therein communicating between the upper and lower faces of said cap, each said passageway being adapted to be positioned above a different one of the recesses in said plunger housing; a diaphragm positioned between the lower face of said cap and the upper face of said plunger housing, said diaphragm being adapted to cover the recesses in the upper surface of said plunger housing; a plurality of plunger means each being positioned in and extending through a respective one of the passageways in said plunger housing; a first piston means having an opening therethrough, said first piston means being positioned in said piston housing between the base thereof and the lower surface of the plunger housing for reciprocal movement along the central axis of said piston housing in sealing engagement with the inner surface of said tubular sidewall, the upper surface of said first piston having such configurtion that a first chamber is formed between the outer portions thereof and the lower surface of said plunger housing; a second piston means positioned in said piston housing between the base thereof and the lower surface of said first piston means for reciprocal movement along the central axis of said piston housing in sealing engagement with the inner surface of said tubular sidewall, said second piston means having projecting portion which extends upwardly from the main portion of said second piston through said opening in said first piston means and in sealing. engagement therewith for reciprocal movement therein relative to said first piston means, said first and second piston means being of such configuration that when said pistons are brought into abutting relationship, there is a gap between the outer portions of the lower face of said first piston and the outer portions of the upper face of said second piston, said gap defining a second chamber; first spring means positioned in said first chamber between the lower face of said plunger housing and the upper face of said first piston means to urge said first piston means away from said lower face of said plunger housing; second spring means positioned in a third chamber defined by the lower face of said second piston means and the base portion of said piston housing to urge said second piston means toward said plunger housing, said second spring means extending from the inner surface of the tubular sidewall to an opening extending through said second spring means; a stop means extending downwardly from the lower surface of said second piston and through the opening extending through said second spring means, said stop means extending downwardly a distance sufficient to limit the downward movement of said piston; a first passageway extending through the tubular sidewall of said piston housing and into communication with said first chamber; a second passageway extending through the tubular sidewall of said piston housing and into communication with said second chamber; a third passageway extending through the tubular sidewall and into communication with said third chamber; a groove in the inner surface of the tubular sidewall of said piston housing in communication with said third passageway and extending in said third chamber from the upper surface of the base portion to a point above that where the uppermost portion of said second spring means contacts said tubular sidewall; a groove in the upper surface of the base portion of said piston housing extending from the groove in the tubular sidewall to a point beneath said stop means; wherein the lengths of said plunger means and the configurations of said first and second piston means are such that when said second piston means is in its uppermost position and said first piston is in its lowermost position only a first set of said plunger means engages said diaphragm to seal the corresponding spaces between adjacent pairs of recesses, and when said first and second piston means are in their uppermost positions all of said plunger means engage said diaphragm to seal the corresponding spaces between adjacent pairs of recesses, and when said second piston means is in its lowermost position and said first piston is in its uppermost position only a second set of said plunger means engages said diaphragm to seal the corresponding spaces between said adjacent pairs of recesses; means for releasably securing said cap to said plunger housing; and means for releasably securing said plunger housing to said piston housing.