A cam ring is capable of moving while rolling on a cam support surface. The cam ring is provided such that within a range in which the cam ring can move on the cam support surface, an eccentricity amount increasing-side angle is always greater than an eccentricity amount decreasing-side angle. On a plane perpendicular to the rotation axis of a driving shaft, the eccentricity amount increasing-side angle is an angle, in a direction opposite to a rotation direction of the driving shaft, from a first reference line, which connects a tangent point between the cam ring and the cam support surface to a rolling center of the cam ring, to a starting end of a first discharge port. The eccentricity amount decreasing-side angle is an angle, in the rotation direction of the drive shaft, from the first reference line to a terminal end of the first discharge port.

A shunt-enhanced decompression and pulsation trap (SEDAPT) for a screw compressor assists internal compression (IC), reduces gas pulsation and NVH (Noise, Vibration & Harshness), and improves off-design efficiency, without using a slide valve and/or a serial pulsation dampener. The SEDAPT includes an inner casing, e.g., an integral part of the compressor chamber, and an outer casing, e.g., surrounding part of the inner casing near the compressor discharge port, forming at least one diffusing chamber with an outflow orifice or nozzle equipped with an ODV (one-direction valve) at the outflow exit and a feedback region that provides a feedback outflow loop between the compressor chamber and the compressor discharge port. The SEDAPT automatically bleeds or compensates cavity pressure to meet different outlet pressures, eliminates or reduces energy waste, gas pulsations and NVH associated with any over-compression and under-compression before the discharge port opens.

The invention relates to a displacement machine according to the spiral principle, in particular a scroll compressor or scroll expander, with a high-pressure chamber, a low-pressure chamber and an orbiting displacement spiral, which engages in a counter-spiral such that chambers are formed between the displacement spiral and the counter-spiral for receiving a working medium, wherein a counter-pressure chamber is formed between the low-pressure chamber and the displacement spiral. According to the invention a pressure regulating device which is fluidically connected to the counter-pressure chamber sets a pressure difference between the counter-pressure chamber and the low-pressure chamber by means of a set value specified by the computing unit.

A portable fluid pump comprises a tank, a positive displacement pump comprising a fluid inlet and outlet, and an electric motor that drives the positive displacement pump, wherein the electric motor is a brushless variable speed electric motor operating at 110 volts or less. A conduit diverts fluid pumped by the positive displacement pump back into the tank and an actuated valve assembly controls fluid flow through the conduit and, therefore, a pressure of fluid flow through the fluid outlet. A pair of sensors measure, respectively, a pressure and a flow rate of fluid flow through the fluid outlet. A system controller receives a target fluid pressure and fluid flow rate and adjusts a throttle position of the actuated valve assembly and a speed of the electric motor such that pressure and flow rate readings from the sensors substantially match, respectively, the target fluid pressure and fluid flow rate.

A seal assembly for sealing a pump shaft in a rotary piston pump configured for conveying pump-conveyed fluid comprises a sealing-fluid pump device having a pump inlet and a pump outlet. A blocking chamber is connected to the pump outlet and is disposed so as to neighbor the pump chamber of the rotary piston pump and is sealed in relation to the pump chamber by means of a first shaft seal that encloses the pump shaft. The blocking chamber by way of the pump outlet is impinged with a fluid pressure resulting from the fluid pressure differential that is generated by the sealing-fluid pump device, whereby said fluid pressure interacts with the first seal assembly to seal the pump chamber in relation to the egress of pump-conveyed fluid from the pump chamber along the pump shaft.

A motor driven compressor apparatus includes a rotary shaft rotatably supported in a housing, an eccentric bushing eccentrically coupled to the rotary shaft, and a swing pin configured to connect the eccentric bushing and the rotary shaft with each other, wherein the rotary shaft is provided with a flow path configured to pass through the center of a cross-section in the longitudinal direction and, in one direction at which the eccentric bushing is disposed, a first pin insertion hole which communicates with the flow path and into which the swing pin is inserted, the eccentric bushing is provided with a second pin insertion hole into which the swing pin is inserted in the other direction at which the rotary shaft is disposed, and refrigerant leaks between the swing pin and the first pin insertion hole.

The present disclosure relates to a motor driven compressor apparatus capable of reducing abrasion of an orbiting scroll by implementing decompression without a separate decompression mechanism when a compressor is driven and increasing efficiency of the compressor by adjusting the pressure of a refrigerant, wherein a flow path, which is configured to pass through a center of a cross section in a longitudinal direction, and a first pin insertion hole in one direction at which the eccentric bushing is disposed and configured to communicate with the flow path and into which a swing pin is inserted, are formed in the rotary shaft, a second pin insertion hole, into which the swing pin is inserted, is formed in the eccentric bushing in the other direction at which the rotary shaft is disposed, and the refrigerant leaks between the swing pin and the first pin insertion hole.

A shunt-enhanced compression and pulsation trap (SECAPT) for a screw compressor assists internal compression (IC), reduces gas pulsation and NVH, and improves off-design efficiency, without using a slide valve and/or a serial pulsation dampener. The SECAPT includes an inner casing (e.g., an integral part of the compressor chamber) and an outer casing (e.g., surrounding part of the inner casing near the compressor discharge port) forming at least one diffusing chamber with a nozzle and a feedback region that provides a feedback flow loop between the compressor chamber and the compressor discharge port. The SECAPT automatically compensates cavity pressure to meet different outlet pressures (hence eliminating under-compression and/or over-compression when the discharge port opens), partially recovers potential energy associated with the under-compression (UC), and traps and attenuates gas pulsations and noise before the discharge port opens.

An embodiment of a system with a minute measure of pulsatility in a flow of a fluid is described that comprises a first pump configured to flow the fluid to a junction at a first flow rate that comprises a measure of pulsatility; and a second pump configured to flow a portion of the fluid from the junction at a second flow rate that is less than the first flow rate to produce a flow of the fluid at a third flow rate from the junction with a minute measure of pulsatility.

A pump apparatus includes a housing, a shaft, a rotor, a plurality of vanes, a pressure relief passage, and a bearing. The housing includes suction ports and discharge ports. The rotor and the vanes transport hydraulic oil to the discharge ports. The hydraulic oil is sucked from the suction ports. The pressure relief passage is defined in a portion of the housing facing an outer peripheral surface of the shaft. The pressure relief passage brings the discharge ports into communication with a low pressure region where the hydraulic oil is low in pressure. When a pressure of the hydraulic oil in the discharge ports is lower than a first predetermined pressure, the bearing keeps the pressure relief passage out of communication with a passage. When the pressure of the hydraulic oil in the discharge ports has increased to reach or exceed the first predetermined pressure, the bearing brings the pressure relief passage into communication with the passage.