A compressor lubrication system including a positive displacement pump, a pressure relief valve assembly, and a divider block. The pressure relief valve assembly includes a housing that has an opening to the fluid distribution system and a relief passage. A conduit is connected from the relief passage to a fluid reservoir. The assembly also includes a pressure relief valve that has an open position in which fluid from the fluid distribution system can enter the relief passage, and a closed position in which fluid is prevented from entering the relief passage. A biasing element maintains a biasing force on the pressure relief valve. The pressure relief valve is maintained in the closed position when the biasing force exceeds the fluid force on the pressure relief valve and the pressure relief valve moves into the open position when the fluid force exceeds the biasing force.

A relief valve assembly includes a housing assembly defining a chamber therein. The relief valve assembly includes a piston. The piston may be at least partially disposed within the chamber. The relief valve assembly includes a pilot inlet. The pilot inlet may be configured to provide a pilot pressure proximate a second end of the chamber. The relief valve assembly includes an overpressure inlet sealed from a first end of the chamber by the piston. The overpressure inlet may be configured to provide an inlet pressure which may actuate the piston when the inlet pressure exceeds the pilot pressure.

A compressor lubrication system including a positive displacement pump, a pressure relief valve assembly, and a divider block. The pressure relief valve assembly includes a housing that has an opening to the fluid distribution system and a relief passage. A conduit is connected from the relief passage to a fluid reservoir. The assembly also includes a pressure relief valve that has an open position in which fluid from the fluid distribution system can enter the relief passage, and a closed position in which fluid is prevented from entering the relief passage. A biasing element maintains a biasing force on the pressure relief valve. The pressure relief valve is maintained in the closed position when the biasing force exceeds the fluid force on the pressure relief valve and the pressure relief valve moves into the open position when the fluid force exceeds the biasing force.

A piston pump for delivering fluids includes a piston, a cylinder element and a pressure chamber which is arranged between an inlet valve and an outlet valve and is closed by a cover, wherein a throttling mechanism for throttling the fluid flow is provided in the fluid flow downstream of the outlet valve, and a vehicle brake system has a piston pump of this type. The throttling mechanism includes a movable annular disc which is guided on the cylinder element and the internal diameter of which is adapted to the external diameter of the cylinder element, wherein the axial travel of the annular disc sets a variable first throttle cross section.

In a check valve for a compressor, a valve element includes an abutting surface and an outer circumferential surface. A valve hole includes a large-diameter portion and a small-diameter portion. A communicating window has such a shape that an opening area thereof gradually becomes larger with increasing distance from a valve seat. The check valve has an open state, a fully closed state, and a buffering state. When the abutting surface separates from the large-diameter portion and the outer circumferential surface opens the communicating window, the open state is defined. When the abutting surface closes the large-diameter portion and the outer circumferential surface interrupts communication through the communicating window, the fully closed state is defined. When the abutting surface separates from the large-diameter portion and the outer circumferential surface interrupts communication through the communicating window, the buffering state is defined. The hunting phenomenon is suppressed.

An adjustment apparatus is used for ultrasound examination of a subject by transmitting ultrasound to the subject and receiving the ultrasound reflected from the subject. The apparatus includes: a change unit configured such that one end is connected to a suction pump and the other end is provided at a portion of a channel leading to a contact portion with the subject, to change suction force of the suction pump on the other end; and a damper for suppressing change in the suction force. The change unit includes: a cylinder having first and second portions for communicating with one end side and the other end side of the channel, respectively; a piston slidable in the cylinder to change a communication state between the first and second portions; and a spring for biasing the piston toward a direction of causing the first and second portions not to communicate with each other.

A fluid-damped valve comprises a body defining an internal cavity having an inlet for ingress of a fluid and an outlet for egress of the fluid, and a closure member having a narrowed end portion. The closure member is movably disposed within the internal cavity intermediate the fluid inlet and the fluid outlet. The valve includes a seat configured to sealingly receive the closure member. The seat defines a constricted portion of the internal cavity configured to non-sealingly receive the narrowed end portion and damp the flow of the fluid through the fluid-damped valve.

Flow control valves may be positioned downstream of water meters to increase pressure and compress entrained water vapour passing through the meters. However, turbulence within such valves can cause the valve's head to move radially, bending a shaft within the valve which may break. Accordingly, there is provided a flow control valve comprising: a housing having a flow passage; a valve seat defined within the flow passage; a valve head moveable to a closed position to engage the valve seat and seal the flow passage; a shaft secured to the valve head; a support slidingly mounting the shaft within the housing; a spring biasing the valve head to the closed position and configured to maintain the valve head in the closed position until a predetermined pressure is applied; and a guide assembly extending along at least a portion of the flow passage to constrain radial movement of the valve head.

A valve member for a spring-loaded valve assembly includes a top portion having a spring retaining recess, the spring retaining recess extending into the top portion to form a void space, the void space to receive at least one coil of a spring, the spring retaining recess having a recess diameter that is smaller than a top portion diameter, wherein the recess diameter is larger than a rest diameter of a spring base including the coil, the spring retaining recess blocking expansion of the at least one coil when the spring is compressed. The valve member also includes a bottom portion coupled to the top portion. The valve member further includes a sealing element positioned axially below a shoulder of the top portion and legs coupled to the bottom portion.

Hydraulic fluid release valve assemblies are described herein. The hydraulic fluid release valve assemblies may include a hydraulic unit base with a hydraulic fluid return channel and a hydraulic fluid release valve that is at least partially inserted in the hydraulic fluid return channel. The hydraulic fluid release valve assembly may further include a driving assembly to contact with the hydraulic fluid release valve to apply a pushing force on the hydraulic release valve to open the hydraulic fluid release valve, and an electrically powered driver connected to the driving assembly, the electrically powered driver, when actuated, causes the driving assembly to move to apply the pushing force to the hydraulic fluid release valve.