Patent ID: 8783652

Claim:
An apparatus for controlling liquid flow comprising an orifice and an adjacent flexible diaphragm separated from each other by a gap through which a liquid flows, said diaphragm being sufficiently flexible to vary the gap for controlling the rate of liquid flowing through the orifice or to provide a positive liquid shutoff of liquid flowing through the orifice and a spring to exert a force on said flexible diaphragm for positive liquid flow shut off; wherein a piezoelectric transducer is in contact with said flexible diaphragm and positioned between said diaphragm and a piston, the piston operable by compressed gas to create a force to counter the force of said spring on said flexible diaphragm and place said diaphragm in a position for liquid flow control wherein the spring is capable of exerting a force on the piezoelectric transducer to move the transducer against the flexible diaphragm for positive liquid flow shutoff.