Pressure differential switch device

Claim 1

A pressure differential switch device comprising a casing, a flexible movable annular diaphragm fixedly mounted about its periphery in said casing to divide said casing into a first chamber and a second chamber, means for admitting fluid pressures into said chambers for moving said diaphragm, a cylindrical member closed at one end and open at the opposed end and mounted axially in the center of said annular diaphragm for movement therewith, stop means within the first chamber of said casing for limiting axial movement of said diaphragm, a permanent annular magnet mounted on the outer wall of said cylindrical member for movement therewith, a reed switch assembly mounted within said cylindrical member, one end of said reed switch assembly passing through the open end of said cylindrical member and being secured to said casing and means for connecting the contacts of said reed switch assembly to lead wires, wherein said means for connecting the contacts of said reed switch assembly to lead wires includes a pair of U-shaped connectors, the intermediate portions of each being securely mounted in said casing, one end of each U-shaped connector being operatively connected to the respective contacts of said reed switch assembly and the other end of each U-shaped connector being disposed for receiving a conventional detachable female plug for connection to said lead wires, whereby when the pressure in said second chamber exceeds that in said first chamber by a predetermined amount said magnet will be moved by said cylindrical member in response to movement of said diaphragm in one direction to a first position in which the magnetic field of said magnet will close the contacts of said reed switch assembly, the movement of said diaphragm being limited by said stop means in said first chamber to prevent continued movement of said magnet in said direction beyond the first position.