Diaphragm assembly for pressure operated pilot controlled shut-off valve

Claim 1

In a solenoid controlled pressure operated diaphragm shut-off valve, a valve body having a valve cavity therein, an inlet passageway opening to said cavity and having communication with a source of fluid under pressure, an outlet port, an annular valve seat disposed radially inwardly of said inlet passageway and having communications with said outlet port, an annular sealing groove extending about said outlet port, a flexible diaphragm movable between open and closed positions for cooperating with said annular valve seat to control the flow of fluid between said inlet passageway and said outlet port and sealed along its margin in said sealing groove, said diaphragm having a thin-walled bellows-like annular portion disposed inwardly of its peripheral portion and a disk-like central portion, said diaphragm defining a fluid pressure chamber between said inlet passageway and said outlet port, a relatively rigid poppet valve insert structure backing up said disk-like central portion and having a disk-like portion reinforcing said diaphrAgm on one side thereof and a central stem body portion extending from said insert structure disklike portion through said diaphragm beneath said disk-like central portion of said diaphragm and having guiding engagement with said outlet port, said central body stem portion having an intermediate portion of a diameter less than said outlet port for throttling fluid flow from said inlet passageway to said outlet port and a base portion of a length at least sufficient to maintain contact with the periphery of said outlet port as said diaphragm moves between the open and closed positions, said base portion having a plurality of ribs radially spaced about its peripheral surface for sliding engagement with said outlet port, a central pilot orifice leading through said central body stem portion of said insert structure and said disk-like portion of said diaphragm to provide communication with said outlet port, a bleed means radially spaced from said pilot orifice providing constant fluid communication between said inlet passageway and said fluid pressure chamber, said bleed means comprising a plurality of circumferentially spaced screening holes leading through said diaphragm, a single bleed hole leading through said insert having a smaller cross sectional flow area than the cross sectional flow area of said central pilot orifice, and passageway means between said circumferentially spaced screening holes and said single bleed hole leading through said insert structure, an armature having a valve at one end thereof cooperating with said central pilot orifice to open and close said pilot orifice, and a solenoid coil energizable to move said armature for opening and closing said pilot orifice and for maintaining closed said orifice upon contact of said orifice by said valve.