Zero displacement diaphragm valve

Claim 1

In a zero displacement diaphragm valve, the combination of: a. a housing having coaxial actuator and valve seat chambers; b. a valve seat coaxial with said actuator and valve seat chambers, said valve seat being disposed in said valve seat chamber and facing said actuator chamber, said valve seat being generally frusto-conical in form and tapering outwardly and away from said actuator chamber and having a central valve port therein communicating with said vaLve seat chamber; c. said housing being provided with ports respectively communicating with said valve seat chamber and said valve seat; d. a diaphragm carried by said housing and separating said valve seat chamber and said actuator chamber and including a valve element engageable with said valve seat, the periphery of said diaphragm being secured to said housing in substantially the same plane as the small end of said valve seat, said diaphragm being movable between a closed position in which the central portion thereof engages said small end of said valve seat to close said valve port and an open position in which said central portion is displaced away from said valve port to open the same, said diaphragm when in said open position being deformed to provide an annular surface generally parallel to the outer frusto-conical surface of said valve seat to form a generally frusto-conical fluid passage therebetween directing fluid flow from said valve port to the housing port communicating with said valve seat chamber; e. an actuator in and movable axially of said actuator chamber and connected to said diaphragm so as to move said valve element toward and away from said valve seat; f. a liquid in and filling said actuator chamber; and g. means for moving said actuator.