Pneumatic acutated switch

A pneumatic actuator comprising:

• a housing having a pressure chamber and a pressure relief chamber;
• a diaphragm within said housing having a first side facing said pressure chamber and a second side facing said pressure relief chamber, said diaphragm formed of a flexible material and having a neutral unflexed configuration;
• a rigid pressure plate within said housing disposed against said second side of said diaphragm for movement with said diaphragm, said pressure plate having a sealing surface facing said diaphragm defining an open space between said plate and said diaphragm when said diaphragm is in said neutral unflexed configuration, a first vent passage communicating with said sealing surface, and a second vent passage communicating with said sealing surface and with said pressure relief chamber;
• a port through said diaphragm connecting said pressure chamber with said first vent passage, said port dimensioned wherein a pressure change within said pressure chamber below a predetermined rate of change is vented from said pressure chamber through said port, through said vent passages and through said opening defined between said pressure plate and said diaphragm, and a pressure change at a rate above a predetermined rate of change causes said diaphragm to flex into surface contact with said sealing surface of said pressure plate so as to collapse the open space therebetween sealing said diaphragm against said pressure plate, thereby isolating said first vent passage from said second vent passage and causing said diaphragm and said pressure plate to move in response to said pressure increase in said pressure chamber;
• and
• an actuator movable in response to movement of said diaphragm.

A diaphragm and pressure plate assembly for moving an actuator element in response to a rapid pressure increase exerted on one side of said diaphragm, said assembly comprised of:

• a resilient, flexible diaphragm element having a predetermined surface profile in a neutral unflexed condition,
• said diaphragm having a first side positioned adjacent a pressure chamber and a second side positioned adjacent a pressure relief chamber,
• a rigid pressure plate positioned against said second side of said diaphragm, said pressure plate having a mating surface with surface contours which form an open space with said second side of said diaphragm when said diaphragm is in said neutral unflexed condition, said pressure plate further including a first vent passage communicating with said surface contours at a first location on said pressure plate and a second vent passage communicating with said surface contours at a second location on said pressure plate, said vent passages and said open space define a pressure vent path when said diaphragm is in said neutral position,
• a port through said diaphragm communicating with said pressure chamber and with said first vent passage, for venting gradual pressure buildups in said pressure chamber through said vent path, said diaphragm flexing into surface engagement with said surface contours on said pressure plate and isolating said first vent passage from said second vent passage when a pressure increase above a predetermined rate of change exists in said pressure chamber.

A diaphragm assembly for use in a pneumatic actuated switch comprised of:

• a flexible diaphragm formed of a resilient material having a neutral, unflexed configuration and a predetermined diaphragm surface profile in said unflexed configuration, said diaphragm having an aperture formed therethrough;
• a pressure plate positioned against said diaphragm and having an outer surface defining a pressure plate surface profile generally conforming to the surface profile of said diaphragm so as to mate therewith, said plate having a recessed annular surface facing said diaphragm, said recessed annular surface forming an annular gap with said diaphragm when said diaphragm is in said neutral, unflexed configuration;
• a first vent path formed in said pressure plate within the diameter of said annular surface, said first vent path communicating said annular gap with said port in said diaphragm;
• and
• a second vent path formed in said pressure plate communicating said annular gap with an outer side of said plate.