Liquid flow switch

Claim 1

A liquid flow switch comprising two housings, defining a fluid tight space there between, a flexible pressure responsive diaphragm comprising a flexible material, a diaphragm plate, wherein said diaphragm and said diaphragm plate are secured together by means of a threaded plug, said threaded plug having an opening providing communication between two compartments, whereby the size of said opening functions to determine a differential pressure for a specific flow rate obtained through said opening, said flexible pressure responsive diaphragm separates the space into two said compartments, a rigid member of one said compartment having an edge surface in said space opposed to an edge surface of second compartment and in close proximity therewith, the edge surfaces jointly defining a clamp to hold said pressure responsive diaphragm, a pin extending from said housing provides means for pivoting said pressure diaphragm plate about said pin, an electrical contact mounted on said housing exteriorly of said space, an actuator for actuating said contact to an operative position comprising a flexible flat spring mounted exteriorly of said housing for flexing to a position to close said contact, an axially displacable pin in communication with the interior of said housing, and extending outwardly thereof for bearing against said flexible flat spring to deflect in a direction for closing said contact, an activating element mounted on said diaphragm for movement therewith to contact and engage said pin to actuate it in response to a pressure differential in said compartments flexing the diaphragm in a direction for actuating said liquid flow switch, and connectors for applying the fluid to two said compartments to develop said differential pressure whereby said differential pressure is a function of size of opening in said threaded plug for a specific flow rate.