A scroll compressor includes a fixed scroll and an orbiting scroll and causes the orbiting scroll to perform an orbiting motion to form a suction chamber and a compression chamber. The scroll compressor includes a first space in a back surface center of the orbiting scroll, lubricant in a bottom of a sealed container, a second space provided further on an outer circumference side than the first space on a back surface of the orbiting scroll, a first oil leak path for causing a part of oil in the first space to leak to the second space, an oil return passage for returning most of the oil in the first space to the bottom in the sealed container, a second oil leak path for causing a part of the oil in the second space to leak to the suction chamber, and a third oil leak path.

A scroll compressor is provided that may include a motor; an orbiting scroll; a fixed scroll coupled to the orbiting scroll, and forming a compression chamber together with the orbiting scroll; a frame coupled to the fixed scroll, and configured to support the orbiting scroll; a sealing member mounting groove having a ring shape, and formed on a first surface of the frame contacting the orbiting scroll, or a second surface of the orbiting scroll contacting the frame; and a sealing member including a first sealing portion formed in a ring shape, inserted into the sealing member mounting groove so as to be moveable in an axial direction, and configured to perform a sealing operation between the frame and the orbiting scroll in the axial direction and including a second sealing portion extending from the first sealing portion in the axial direction, and configured to perform a sealing operation between the frame and the orbiting scroll in a radial direction by contacting an outer side wall surface of the sealing member mounting groove A thickness of the second sealing portion in the radial direction may be smaller than a thickness of the first sealing portion in the axial direction.

A compressor may include first and second scrolls, a seal assembly and a valve ring. The first scroll may include a first end plate having a discharge passage, a modulation port, and a biasing passage. The modulation port may be in communication with a first pocket formed between spiral wraps of the first and second scrolls. The biasing passage may be in communication with a second pocket formed between spiral wraps of the first and second scrolls. The modulation valve ring is axially displaceable relative to the seal assembly and the first scroll between first and second positions. The valve ring may abut an end plate of the first scroll and close the modulation port when in the first position. The valve ring may abut an axially-facing surface of the seal assembly and is spaced apart from the end plate to open the modulation port when in the second position.

A scroll compressor is provided that may include a casing including a rotational shaft, a cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space, a first scroll revolved by rotation of the rotational shaft, a second scroll disposed on or at one side of the first scroll to define a compression chamber together with the first scroll, the second scroll including a discharge, through which a refrigerant pressed in the compression chamber may be discharged, a switching device movably disposed on or at one side of the discharge to selectively open and close the discharge, a back pressure portion including a moving guide that accommodates at least a portion of the switching device, and a top surface that covers one side of the switching device; and an adhesion preventer that reduces a contact area between the switching device and at least a portion of the back pressure portion.

A scroll-type fluid machine reduces intrusion of abrasion powders, generated by sliding of a conductor causing an orbiting scroll side and a fixed scroll side to be conducted, into a compression chamber, and improves reliability of a compressor. The scroll-type machine includes a casing, a fixed scroll having a flange surface attached to the casing, and a wrap portion provided at an end plate, an orbiting scroll having a wrap portion provided at the end plate, and provided in an opposed relationship with the fixed scroll, a drive shaft connected through a crank portion to the orbiting scroll, an orbiting bearing, a face seal portion arranged between the orbiting scroll and the fixed scroll, a cooling fan, and an orbiting scroll side conductive brush.

A sealing arrangement between a rotating plane surface on a rotor and a machine housing prevents flow of process fluid between an internal volume and an external volume of the machine housing. The sealing arrangement includes a piston arrangement, and a sealing bearing ring between the piston arrangement and the rotating plane surface. A fluid supply line supplies pressurized lubrication fluid through the machine housing to a piston cavity, wherein the piston arrangement further includes piston fluid channels and the bearing sealing ring includes lubrication conduits through the bearing sealing ring, corresponding with the piston fluid channels. The pressurized lubrication fluid is arranged for moving the piston arrangement against the sealing bearing ring and thus moving the sealing bearing ring against the sealing surface thus forming a sealing arrangement.

A scroll compressor is provided that may include a first scroll, a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll having a discharge hole that communicates with a compression chamber among the plurality of compression chambers, a back pressure plate that defines a back pressure chamber to accommodate a refrigerant discharged from the discharge hole, a floating plate to define the back pressure chamber, and a sealing member to prevent the refrigerant from flowing between a first surface, which may be a sliding surface of the floating plate, and a second surface, which may face the first surface, of the back pressure plate. The sealing member may include a seal cover that contacts the other one of the first and second surfaces, and a seal, a portion of which may be accommodated in the seal cover. The seal cover may have a friction coefficient less than a friction coefficient of the seal.

Sealing in rotary positive displacement machines based on trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator is described. Seals can be mounted on the rotor, the stator, or both. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides advantages with respect to sealing in the rotary machine. In multi-stage embodiments, the rotor-stator geometry remains substantially constant or varies along the axis of the rotary machine.

The oil-free screw compressor includes: a casing having a rotor chamber; a bearing supporting rotary shafts of screw rotors; a shaft seal device with an oil seal portion and an air seal portion; a ventilation gap positioned between the oil seal portion and the air seal portion; and an atmosphere open passage communicating an atmosphere side of the casing with the ventilation gap communicate. A most narrowed portion, an air seal portion, and oil seal portions are set such that the followings is established:

(La/Sa.sup.2.5)/(Lh/Sh.sup.2.5)>|P2|/ΔPb La: effective shaft seal length Sh: effective open cross-sectional area (most narrowed portion of atmosphere open passage) Lh: effective narrowed length (most narrowed portion of atmosphere open passage) Sa: shaft seal cross-sectional area |P2|: negative pressure in rotor chamber during unloading operation ΔPb: minimum differential pressure in the oil seal portion during the unloading operation

A scroll compressor according to the present invention includes a partition plate that partitions a sealed container into a high-pressure space and a low-pressure space, a fixed scroll adjacent to the partition plate, a orbiting scroll, a rotation restrictor, and a main bearing. The sealed scroll compressor further includes a pillar member having a lower end portion secured in a bearing-side engagement portion provided in the main bearing, and an upper end portion inserted in a scroll-side engagement portion provided in the fixed scroll. The axial distance from the upper end portion of the pillar member to the partition plate is smaller than the length by which the pillar member and the bearing-side engagement portion are coupled together.