Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system and tank pressure spikes. Because the pilot ball downstream of the damping orifice is held off the pilot seat in the normal starting condition by a pilot return spring, the main piston will open immediately when system pressure overcomes the low bias pressure of the main spring. A pilot pressure bypass port, which selectively deactivates the pilot chamber features, may also be included.

Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system and tank pressure spikes. Because the pilot ball downstream of the damping orifice is held off the pilot seat in the normal starting condition by a pilot return spring, the main piston will open immediately when system pressure overcomes the low bias pressure of the main spring. A pilot pressure bypass port, which selectively deactivates the pilot chamber features, may also be included.

Abstract: A pilot operated pressure valve which limits the rate of start-up pressure rise (“soft start-up”) and substantially eliminates excessive system pressure spikes. The valve includes an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the threshold operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds the inlet threshold pressure which is just sufficient to open a spring biased pilot ball downstream of the damping orifice.

Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system pressure spikes, the valve including an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds a preselected inlet pressure level sufficient to open a spring biased pilot ball downstream of the damping orifice. The inlet will open an exit port upstream of the main orifice for discharging pressurized fluid from the valve back to a supply tank when inlet pressure exceeds the operating pressure.

Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system pressure spikes, the valve including an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds a preselected inlet pressure level sufficient to open a spring biased pilot ball downstream of the damping orifice. The inlet will open an exit port upstream of the main orifice for discharging pressurized fluid from the valve back to a supply tank when inlet pressure exceeds the operating pressure.

Abstract: Two pressure control valves have most components in common. One valve is a direct-acting sequence valve and the other a vented counterbalance valve with pilot assist. Both valves have a set opening pressure which is insensitive to secondary port pressure. Both valves may provide free reverse flow. The valves include a spring force reduction chamber which receives hydraulic fluid at primary port pressure. Part of the opening force exerted at the primary port is offset by pressure in the spring force reduction chamber so that a spring having a smaller spring constant may be used to resist opening force. This offsetting force may be readily modified by changing the diameter of the piston shaft of the valve.

Abstract: A direct-acting, differential piston relief valve has a spring chamber pressurized with fluid from a passage through the piston. The fluid within the chamber is at the same pressure as that at the inlet valve and provides a valve closing pressure against the inner face of the piston. The piston face at the inlet valve has an annular extension. The inner circumference of this extension meets the spherical valve seat when the valve is closed. The diameter of the inner face of the piston is smaller than the diameter of the piston face annular extension. Inlet pressure working on this area difference produces the hydraulic force which is opposed by the spring. No piston face area is exposed to forces tending to close the valve due to Bernoulli effects when the valve begins to open. The spring within the spring chamber has spring guides at each end which contain a ball. The ball transmits the spring force to the piston on one end and a sealed closure at the other end.

Abstract: A flow regulator valve has a first fluid opening at one end and a second fluid opening at the side of the valve body. A sleeve bore extends from the first opening and contains a stem which is co-axial with the sleeve bore, but spaced from it. A compensating spool is slideably mounted between the sleeve bore and the stem and may move to completely close the second opening or to provide partial opening. A control spring biases the spool to the open position, but a fluid passage through the stem wall permits the pressure of the fluid at the first opening to be applied to bias the spool to the closed position. A valve element containing an orifice establishes the nominal flow rate desired, while the pressure drop across the spool causes it to assume a position to maintain the desired flow rate. A valve element control spring may be used to maintain the valve element in the "off" position until the pressure rises to a desired threshold. Venting of the cavity in which the valve element is located is provided.