Devices for exchanging properties, such as pressure, between at least two fluid streams and related methods may include pistons coupled to a valve stem. The valve stem and valve body may be configured to define a primary seal between the one or more pistons and the valve body and a secondary seal between the one or more pistons and the valve body.

A scroll compressor that includes a rotating shaft, an eccentric bush having a recess, into which one end of the shaft is inserted, and an eccentric portion eccentric to the shaft, an orbiting scroll operatively connected to the eccentric portion for orbiting, a fixed scroll engaged with the orbiting scroll, and a buffer member interposed between the one end of the shaft and the recess. Therefore, it is possible to prevent damage to the scrolls due to liquid refrigerant compression during initial operation and to prevent an impact sound between the shaft and the eccentric bush due to the rotational clearance therebetween.

To provide a displacement pump that can be assembled while properly maintaining side clearances. The displacement pump (100, 101, 102, 103, 104, 105) of the present invention for sucking and discharging a fluid such as gasoline vapor by changing pressure in a space constituted by an outer peripheral surface of a rotor (1) and an inner wall surface of a casing (2), comprising a side clearance adjusting member (4), rotating with respect to the pump main body (6), for moving a shaft (3) integrally formed with the rotor (1) in an axial direction of the shaft (3).

A rotary piston compressor is disclosed, comprising a housing having an epitrochoidal shaped inner bore, peripheral inlet and exhaust ports located in the bore, and a rotary piston rotatably mounted within the housing. The central portion of each rotary piston flank is configured such that, at the closest point between the flank central portion and the housing between the exhaust port of the trailing compression cycle and the inlet port of the leading compression cycle, the radial spacing between the rotary piston flank and the housing is maintained such that the volumes enclosed by the rotary piston on either side of the closest point in the respective trailing and leading compression cycles are substantially sealed from one another. The end portions of each rotary piston flank are configured such that radial spacing between the rotary piston flank and the housing exceeds that between the central portion and the housing.

A scroll type positive displacement assembly includes a first scroll and a second scroll, where the second scroll is configured to orbit with respect to a center of the first scroll without rotating with respect to the first scroll. Together, the first scroll and the second scroll define a compression chamber between two seal points where the first scroll and the second scroll contact one another as the second scroll orbits with respect to the first scroll during a compression cycle, and the two seal points come together proximate to a discharge port between the first scroll and the second scroll such that there is at least substantially no dead space between the first scroll and the second scroll at an end of the compression cycle. For example, the two seal points remain in sealing contact during at least one hundred and eighty (180) degrees of the compression cycle.

A scroll type positive displacement assembly includes a first scroll and a second scroll, where the second scroll is configured to orbit with respect to a center of the first scroll without rotating with respect to the first scroll. Together, the first scroll and the second scroll define a compression chamber between two seal points where the first scroll and the second scroll contact one another as the second scroll orbits with respect to the first scroll during a compression cycle, and the two seal points come together proximate to a discharge port between the first scroll and the second scroll such that there is at least substantially no dead space between the first scroll and the second scroll at an end of the compression cycle. For example, the two seal points remain in sealing contact during at least one hundred and eighty (180) degrees of the compression cycle.

A rotary pump, preferably a vacuum. pump, featuring: a delivery space including an inlet on a low-pressure side and an outlet on a high-pressure side of the pump; a rotor which is arranged in the delivery space and delivers a fluid from the inlet into the delivery space to the outlet from the delivery space; at least one housing part which delineates the delivery space at least axially; and a drive shaft which is connected in drive terms to the rotor; including at least one sealing element which is connected, secured against shifting and/or rotating, to the drive shaft and/or rotor and forms a radial sealing gap with the housing part.

A rotary vacuum pump includes a housing defining a pump chamber therein and a rotor extending through a first axial end panel into the pump chamber and carrying at least one vane for rotary movement of the vane within the pump chamber. The rotor comprises an annular axial end face configured to seal against a corresponding contact surface of a second axial end panel. An annular groove for reducing noise generation of the rotary vacuum pump during operation is formed at the annular axial end face of the rotor and/or the contact surface of the second axial end panel.

A system for a utility vehicle has a screw compressor and an electric motor. The electric motor drives the screw compressor. The electric motor is connected to the screw compressor by a flange which has at least one cooling connection, and a cooling channel is provided in the flange.

A displacement pump is configured to allow for assembly while properly maintaining side clearances. The displacement pump (100, 101, 102, 103, 104, 105) for sucking and discharging a fluid such as gasoline vapor by changing pressure in a space constituted by an outer peripheral surface of a rotor (1) and an inner wall surface of a casing (2), includes a side clearance adjusting member (4), rotating with respect to the pump main body (6), for moving a shaft (3) integrally formed with the rotor (1) in an axial direction of the shaft (3).