A rotary compressor may include a rotary shaft; a plurality of plates that supports the rotary shaft; a cylinder provided between the plurality of plates to define a compression space, and provided with a vane slot; a roller slidably coupled to the rotary shaft inside of the cylinder, and having a hinge groove on an outer circumferential surface thereof; and a vane, a first end which is slidably coupled to the vane slot of the cylinder, and a second end of which is rotatably coupled to the hinge groove of the roller. At least one of axial end surfaces of the roller facing the plurality of plates is provided with a wear avoiding portion having a predetermined depth. Contact surfaces between the roller and the plate may be suppressed from being in close contact with each other to suppress the roller or the plate from being damaged or a performance of the compressor due to friction loss from being deteriorated, thereby improving reliability and performance of the compressor.

A rotary internal combustion engine has: a rotor; a housing circumscribing a rotor cavity, the rotor received within the rotor cavity, the housing having a peripheral wall and a side housing assembly secured to the peripheral wall, the side housing assembly having plates located at spaced apart ends of the peripheral wall, the plates defining seal running surfaces in sealing engagement with opposed end faces of the rotor, the plates made of silicon carbide.

An external rotor pump has an outer rotor with a sliding surface which is arranged on the outer side thereof, and an opposing body in which the outer rotor is mounted rotatably by way of the sliding surface thereof on an inner guide surface of the opposing body and is in mechanical contact with the inner guide surface. An inner rotor which is mounted such that it can be rotated eccentrically with respect to the outer rotor is provided. The sliding surface or the inner guide surface has a surface structure which has a load-bearing region and a non-load-bearing region which is depressed in contrast with the former.

A device for measuring flow processes of fluids includes an inlet, an outlet, a housing in which is arranged a drivable positive displacement flow meter which includes a positive displacement chamber in which a driven impeller is rotatably arranged, a first supply duct connecting the displacement chamber with the inlet, a first discharge duct connecting the displacement chamber with the outlet, a first inlet port, a second supply duct connected to the inlet, a displacement flow meter bypass with a differential pressure sensor, and an evaluation and control unit which controls the displacement flow meter based on a differential pressure applied to the pressure sensor. Cavitation wear of the positive displacement meter is reduced by the first supply duct opening into a front of the displacement chamber via the first inlet port, and the second supply duct opening into a rear of the displacement chamber via a second inlet port.

A scroll compressor comprising a fixed scroll (15); an orbiting scroll (16) supported in a manner allowing for orbiting motion; a discharge port through which a fluid compressed by the two scrolls (15, 16) is discharged; an end plate step portion (16E) provided on an end plate of the orbiting scroll (16) formed so that a height of the end plate is higher on a center portion side in the direction of a spiral wrap and lower on an outer end side; and a wrap step portion (15E) provided on a wall portion of the fixed scroll (15) that corresponds to the end plate step portion (16E) so that a height of the wall portion is lower on the center portion side of the spiral and higher on the outer end side; wherein the orbiting scroll (16) is treated for surface hardening and the fixed scroll (15) is not treated for surface hardening.

A compressor, a monitoring system and a method of monitoring a compressor that make it possible to monitor the remaining lifetime of a semiconductor element of a motor control system while the processing load is reduced are provided. A compressor (1) includes: a motor control system (10) that controls the rotation speed of a motor (2); a compressor body (3) that compresses air by being driven by the motor (2); a pressure sensor (20) that is provided on the discharge side of the compressor body (3); and a running controller (11) that performs switching between load running and no-load running on the basis of the pressure sensed by the pressure sensor (20). A motor controller (26) of the motor control system (10) calculates a relative temperature of a semiconductor element relative to a reference temperature by using a temperature of the semiconductor element sensed by a temperature sensor (27) at the time of switching from no-load running to load running, and calculates an amount of change in a remaining lifetime of the semiconductor element corresponding to the relative temperature of the semiconductor element, whereby monitoring the remaining lifetime of the semiconductor element.

A pair of intermeshing gears for multi-shaft vacuum pumps, comprising a first running gear and a second running gear is provided, wherein at least the first running gear comprises a first and a second gearwheel, respectively. The first and the second gearwheel are axially arranged in direct contact, wherein the first gearwheel comprises a predetermined number of first cogs of same dimension and the second gearwheel comprises a predetermined number of second cogs, wherein the predetermined number of second cogs is at least one. All of the predetermined number of first cogs have a dimension larger than the dimension of the predetermined number of second cogs to a predetermined amount. The first gearwheel is made of a material with a first elastic modulus. The second gearwheel is made of a material with a second elastic modulus, wherein the first and the second elastic modulus are different.

A scroll compressor is provided that may include a casing having a sealed inner space; a drive motor provided in the inner space of the casing to generate a rotational force; a rotational shaft rotatably coupled to the drive motor; an orbiting scroll formed of an aluminum material, and coupled to the rotational shaft to perform an orbiting movement; a fixed scroll coupled to the orbiting scroll to form a compression space; and an Oldham ring coupled to the orbiting scroll, and formed of a sintered metal. With this structure, it may be possible to prevent the Oldham ring from being worn out due to contact with the orbiting scroll. Further, a weight loss portion or wear-resistant coating layer may be formed on a portion of the Oldham ring, thereby suppressing or preventing vibration noise of the scroll compressor from being increased due to a weight increase of the Oldham ring.

A scroll compressor includes a first scroll and a second scroll engaged with the first scroll to form a compression chamber with the first scroll while performing an orbiting movement with respect to the first scroll. A frame is fixed to a side of the first scroll with the second scroll interposed between the frame and the first scroll and the frame supporting the second scroll in an axial direction. An Oldham ring includes a ring portion and a key portion protruding from the ring portion. The key portion is slidably coupled to a key recess in the frame or the second scroll to enable the second scroll to perform the orbiting movement, and the key portion of the Oldham ring is formed of the same material as the second scroll. A wear preventing member is provided between the key portion and the key recess.

A pump for conveying a fluid includes a casing with a casing inner wall, a pump interior, an inlet opening, an outlet opening, a displacement assembly, and a radial protective element arranged in the pump interior in order to line at least one radial section of the pump interior, the radial protective element bearing against a radial section of the casing inner wall. A fastening element is provided which can be arranged in a fastening position in which the fastening element bears against an edge of the radial protective element and in the process fastens the radial protective element in the pump interior, wherein the fastening element has a longitudinal extent which extends from a first axial end of the pump interior along a recess arranged in the casing inner wall.