Patent ID: 6039070
Filing Date: 2000-03-21
Classification: F16K,G05D,Y10T

Abstract:
A pilot operated pressure valve comprising:an elongated inlet member, an elongated cylindrical hollow main body sealingly connected at one end thereof to and longitudinally extending from said inlet member, an elongated pilot chamber member having a pilot chamber and being mounted within a cylindrical interior of said main body and longitudinally extending at one end thereof from said inlet member, and a pressure adjustment member adjustably sealingly connected to another end of said main body at another end of said pilot chamber member;said inlet member including an inlet port at one end thereof, an outlet port a retainer sealingly connected to another end of said inlet member, a piston slidably mounted within said inlet member, and a main spring positioned within and extending longitudinally along a main chamber formed centrally between said retainer and said piston;a head of said piston defining one end of said main chamber and including a main orifice adjacent said inlet port which allows a relatively small quantity of pressurized fluid at said inlet port to be metered into and fill said main chamber;said retainer including a longitudinally extending damping orifice in fluid communication with said main chamber which allows a relatively small quantity of pressurized fluid in said main chamber to be metered into said pilot chamber from said main chamber;said main spring biasingly urging said piston into sealing engagement against said inlet port until a predetermined inlet pressure equal to a maximum operating pressure of said valve is reached whereupon said piston is opened by axial movement thereof against said main spring to allow pressurized fluid to enter said inlet port and to exit said valve directly from said outlet port;said pilot chamber member including an elongated pilot spring acting at one end thereof within an elongated sleeve of said pilot chamber member against a pilot ball to seal pilot chamber up to a first predetermined fluid pressure within said main chamber;said sleeve longitudinally positionable by said pressure adjusting member within said main body to vary a length of said pilot spring and thus to vary the first predetermined inlet pressure which is required to unseat said pilot ball;said sleeve including a crosshole closed to fluid communication with said pilot chamber by a relief spring biasingly engaged at one end thereof against a relief ball, said relief ball being unseated at a preselected pilot pressure within said pilot chamber to allow pressurized fluid to flow from said pilot chamber through said crosshole and through a relief hole of said main body to exit said valve whereby the pilot pressure in said pilot chamber is substantially below the operating pressure of said valve;said sleeve also including a control orifice which allows a relatively small quantity of pressurized fluid in said pilot chamber to be metered therefrom and to fill a loading chamber defined between another end of said sleeve and said pressure adjustment member;said loading chamber having a net surface area greater than that of said retainer whereby said sleeve is moveably urged against said pilot spring to selectively vary the valve operating pressure between a minimum and a maximum valve operating pressure.