Excess pressure shutoff valve

An excess pressure shutoff valve comprising:

• a housing including inlet and outlet ports:
• a chamber in said housing in pressure communication with at least one of said inlet and outlet ports;
• a valve seat in said housing between said inlet and outlet ports;
• said chamber being defined in part by a diaphragm;
• a valve member movable relative to said valve seat between valve open and valve closed positions;
• and
• a stem interconnecting said diaphragm and said valve member for simultaneous movement;
• said diaphragm consisting of a unitary, one-piece, fluid impervious bistable snap disc having two over-center stable positions corresponding respectively to said valve open and valve closed positions;
• said stem including a reset portion extending from said housing in the valve closed direction.

An excess pressure shutoff valve comprising:

• a housing including an inlet, an outlet, a pressure chamber and a valve seat defining a fluid flow path through said housing;
• a bistable, overcenter, snap-acting diaphragm supported by said housing;
• a valve member cooperating with said valve seat to open and close said flow path;
• a stem interconnecting said diaphragm and said valve member for holding said valve member in the open position when said diaphragm is in a first stable position and for holding said valve member in the closed position when said diaphragm is in the second stable position;
• said pressure chamber being defined in part by said diaphragm for biasing said diaphragm toward said second stable position in response to fluid pressure in said pressure chamber;
• diaphragm biasing means including a spring biasing said diaphragm toward said second stable position;
• and
• manually operable means connected to said diaphragm for resetting said diaphragm from said second to said first stable position.

An excess pressure shutoff valve comprising in combination:

• a housing including a body and a cover defining a cavity between said body and cover;
• a snap-acting diaphragm peripherally clamped in said cavity between said body and cover and having first and second overcenter stable positions;
• said diaphragm lying generally in a plane and cooperating with said body to define a pressure chamber in said cavity on one side of said diaphragm and cooperating with said cover to define a vent chamber on the opposite side of said diaphragm;
• a partition in said body and a valve seat in said partition communicating with said pressure chamber;
• said valve seat lying in a plane parallel with the plane of said diaphragm;
• a first port in said body communicating with said pressure chamber and a second port in said body communicating with said valve seat;
• and
• an elongated plunger assembly movable axially in said housing in a direction normal to said planes of said diaphragm and said valve seat and movable along a line intersecting said diaphragm and said valve seat;
• said plunger assembly being attached to said diaphragm for movement in response to movement of said diaphragm between said first and second stable positions;
• said plunger assembly including a valve member spaced from said valve seat in said first diaphragm position and engaged with said valve seat in said second diaphragm position.

A fluid pressure control valve comprising in combination:

• a housing including a body and a cover defining a cavity between said body and cover;
• a snap acting diaphram peripherally clamped in said cavity between said body and cover and having first and second over center stable positions;
• said diaphram lying generally in a plane and cooperating with said body to define a pressure chamber in said cavity on one side of said diaphram and cooperating with said cover to define a vent chamber on the opposite side of said diaphram;
• said diaphram consisting of a unitary, one-piece, fluid impervious sheet of substantially homogeneous material formed into a snap disc;
• a partition in said body and a valve seat in said partition communicating with said pressure chamber;
• said valve seat lying in a plane parallel with the plane of said diaphram;
• a first port in said body communicating with said pressure chamber and a second port in said body communicating with said valve seat;
• an elongated plunger assembly movable axially in said housing in a direction normal to said planes of said diaphram and said valve seat and movable along a line intersecting said diaphram and valve seat;
• said plunger assembly including a first portion interconnected with said diaphram for movement in response to movement of said diaphram between said first and second stable positions;
• said plunger assembly including a second portion comprising a valve member cooperating with said valve seat to open and close said valve seat;
• and
• said first portion of said plunger assembly including a manually movable reset portion for manual reset of said diaphram from said second to said first stable positions.