A pressure relief valve assembly comprising a valve housing within which is provided a primary pressure relief valve having a valve ball and a valve spring, the valve spring biasing the valve ball in a first direction into a valve seat to prevent the passage of fluid from a fluid line through the valve, and wherein the spring force is selected such that a fluid force above a predetermined set point acting against the ball in a second direction opposite the first direction causes the ball to move out of the valve seat against the spring force to allow fluid to flow from the fluid line through the valve seat and through the valve, and wherein a secondary valve is positioned relative to the primary valve to retain fluid around the valve spring of the primary valve at a fluid force below the predetermined set point.

A connector for transferring fluid and method therefor. The connector may have a first port and a second port which may be coupled together at a main channel with a valve element therein controlling fluid flow through the first port. The first port joins the main channel to provide a fluid path around the valve element and through the second port.

A pressure compensation valve comprises a valve body, a valve sleeve fixedly mounted on the valve body, and a spool disposed in a valve hole of the valve body and capable of moving. The pressure compensation valve can change the pressure compensation characteristic, that is, the pressure compensation valve can change the difficult degree of the pressurized oil liquid flowing by changing an effective pressure acting surface of the pressure compensation valve The structure is simple, requires low cost, and increases the utilization rate of a product.

A pressure relief valve for a reservoir has a housing body forming first and second subchambers in fluid communication. A first opening in a bottom surface of the housing body forms a first valve seat. At least one second opening in the bottom surface forms a second valve seat along an outer perimeter. A diaphragm member is biased against the second valve seat and is configured to deflect off of the second valve seat under a negative pressure. A sealing ball is gravitationally biased against the first valve seat and raises off the first valve seat in response to a positive pressure. A cover sheet on an upper surface of the housing body partially encloses the chamber and traps the sealing ball in the first subchamber. The cover sheet includes an aperture aligned with the second subchamber providing an ambient pressure port coupled to ambient atmosphere.

A pressure relief valve for a reservoir has a housing body forming first and second subchambers in fluid communication. A first opening in a bottom surface of the housing body forms a first valve seat. At least one second opening in the bottom surface forms a second valve seat along an outer perimeter. A diaphragm member is biased against the second valve seat and is configured to deflect off of the second valve seat under a negative pressure. A sealing ball is gravitationally biased against the first valve seat and raises off the first valve seat in response to a positive pressure. A cover sheet on an upper surface of the housing body partially encloses the chamber and traps the sealing ball in the first subchamber. The cover sheet includes an aperture aligned with the second subchamber providing an ambient pressure port coupled to ambient atmosphere.

Embodiments of a compressor cutoff are presented. In an embodiment, the present invention includes apparatus for cutting off the flow of gas/liquid in the event of compressor failure or breakdown. In this embodiment, gas/liquid flows from its source through one or more passageways into a first input chamber, and also through one or more other passageways into a second input chamber, where the first and second input chambers are separated by a stop plunger. During the down-stroke of the compressor's piston, gas/liquid in the first chamber passes (or is drawn) through an inlet valve of the piston bore, and during the up-stroke of the piston that gas/liquid is forced through an outlet valve to a tank or other compressed gas/liquid receptacle. So long as the compressor operates normally, the pressure in the two input chambers (i.e., on each side of the stop plunger) will be substantially equal, thereby keeping the stop plunger in place. If, however, the compressor fails in a manner that exposes gas/liquid in the piston bore to the atmosphere, or otherwise results in a decrease in pressure in the piston bore, the pressure in the first input chamber will fall below the pressure in the second input chamber, thereby causing the stop plunger to move to a position in which it blocks the flow of gas/liquid from entering the inlet valve of the piston bore.

A connector for transferring fluid and method therefor. The connector may have a first port and a second port which may be coupled together at a main channel with a valve element therein controlling fluid flow through the first port. The first port joins the main channel to provide a fluid path around the valve element and through the second port.

A hydraulic steering unit is described comprising a housing (1) and a non-return valve (2) having a ball (3) and a valve seat (4) at an end of a channel (5) in the housing (1), wherein a movement of the ball (3) away from the valve seat (4) is limited by an abutment (7) in the channel (5). Such a steering unit should have a non-return valve which can be produced with low costs. To this end the abutment (7) extends transversely through the channel.

A connector for transferring fluid, the connector may have a first port, a second port, and a third port which may be fluidly coupled together at an internal chamber with a first valve element therein controlling fluid flow through the second port. The connector can have ribs extending along the connector to provide a fluid path around the valve element and between the first port and the second port. The valve element can separate the internal chamber into an air chamber and a liquid chamber, and the third port can be continuously coupled to the liquid chamber regardless of a position of the valve element.

A pressure relief valve assembly comprising a valve housing within which is provided a primary pressure relief valve having a valve ball and a valve spring, the valve spring biasing the valve ball in a first direction into a valve seat to prevent the passage of fluid from a fluid line through the valve, and wherein the spring force is selected such that a fluid force above a predetermined set point acting against the ball in a second direction opposite the first direction causes the ball to move out of the valve seat against the spring force to allow fluid to flow from the fluid line through the valve seat and through the valve, and wherein a secondary valve is positioned relative to the primary valve to retain fluid around the valve spring of the primary valve at a fluid force below the predetermined set point.