A squeeze film damper assembly for a compressor includes a damper sleeve configured to be disposed about a rotor shaft of the compressor. The damper sleeve includes a pressure dam pocket formed in an inner circumference of the damper sleeve. The pressure dam pocket is configured to receive a flow of lubricant and to pressurize the flow of lubricant via rotation of the rotor shaft. The damper sleeve includes an outlet passage extending from the pressure dam pocket to an outer circumference of the damper sleeve. The squeeze film damper assembly also includes a bearing housing disposed about the damper sleeve to form a damper gap extending between the outer circumference of the damper sleeve and the bearing housing. The damper gap is fluidly coupled to the outlet passage and is configured to receive the flow of lubricant from the pressure dam pocket.

A scroll pump has a tip seal between an axial end of the scroll blade of one of stationary and orbiting plate scrolls of the pump and the plate of the other of the stationary plate and orbiting plate scrolls. The scroll pump may have a ballast gas supply system and use the operation of the ballast gas supply system to assess the condition of the tip seal. Alternatively, the scroll pump may have two pressure sensors that sense pressure at two locations spaced along a compression mechanism of the pump to assess the condition of the tip seal.

A positive displacement device includes a first cylinder, a second cylinder disposed within the first cylinder, and a third cylinder disposed around the first cylinder. An interior surface of the first cylinder and an exterior surface of the second cylinder define an inner cavity. An exterior surface of the first cylinder and an interior surface of the third cylinder define an outer cavity. A partition between the interior surface of the first cylinder and the exterior surface of the second cylinder divides the inner cavity into inner regions, and another partition between the exterior surface of the first cylinder and the interior surface of the third cylinder divides the outer cavity into outer regions. The second cylinder and the third cylinder orbit with respect to the first cylinder to create alternating regions of high pressure and low pressure in the inner regions and the outer regions.

In a method for manufacturing an anti-rotation ring of a scroll type compressor, wherein the anti-rotation ring is provided in an anti-rotation mechanism for preventing a movable scroll from rotation on its own axis and made of a metal, the steps of the method include drawing a steel plate into a first intermediate body having a bottomed cylindrical shape, punching the bottom of the first intermediate body thereby to make a second intermediate body and ring forming the second intermediate body.

In a method for manufacturing an anti-rotation ring of a scroll type compressor, wherein the anti-rotation ring is provided in an anti-rotation mechanism for preventing a movable scroll from rotation on its own axis and made of a metal, the steps of the method include drawing a steel plate into a first intermediate body having a bottomed cylindrical shape, punching the bottom of the first intermediate body thereby to make a second intermediate body and ring forming the second intermediate body.

A sectional sealing system for water-spray type screw rotor compressor that is configured to prevent the intermixing of coolant and working fluid from a compression chamber with lubricant used to lubricate at least a bearing system of a rotor. The sealing system may include suction side and discharge side sealing portions that are positioned about first and second shafts, respectively, of the rotor. The suction side sealing portion may include a first seal, a first labyrinth seal, and a second labyrinth seal, the first seal being in proximity to a suction side of the compression chamber. The discharge side sealing portion may include a plurality of first seals, a second seal, a first labyrinth seal, and a second labyrinth seal, the plurality of first seals of the discharge side sealing portion being in proximity to a discharge side of the compression chamber.

An oil-free screw compressor includes: a casing having a rotor chamber; a bearing supporting rotary shafts of the screw rotors; a shaft seal device including an oil seal portion and an air seal portion; an atmosphere open hole formed in the shaft seal device; at least one communication hole formed in the rotary shaft; and an annular space communicating the atmosphere open hole with the at least one communication hole communicate with each other. The annular space includes an inner peripheral annular space formed on an inner peripheral side of the casing. Assuming an open cross-sectional area of the inner peripheral annular space as S1, a total open cross-sectional area of the communication holes as S2, an open cross-sectional area of the i-th communication hole out of the communication holes as S2i, and the number of communication holes as n (n being a natural number of 1 or more), a following relationship is satisfied.

[00001]$S.Math..Math.1\geqq S.Math..Math.2=\underset{i=1}{\overset{n}{.Math.}}.Math..Math.S.Math..Math.2.Math.i$

An oil-free screw compressor includes: a casing having a rotor chamber; a bearing supporting rotary shafts of the screw rotors; a shaft seal device including an oil seal portion and an air seal portion; an atmosphere open hole formed in the shaft seal device; at least one communication hole formed in the rotary shaft; and an annular space communicating the atmosphere open hole with the at least one communication hole communicate with each other. The annular space includes an inner peripheral annular space formed on an inner peripheral side of the casing. Assuming an open cross-sectional area of the inner peripheral annular space as S1, a total open cross-sectional area of the communication holes as S2, an open cross-sectional area of the i-th communication hole out of the communication holes as S2i, and the number of communication holes as n (n being a natural number of 1 or more), a following relationship is satisfied.

[00001]$S.Math..Math.1\geqq S.Math..Math.2=\underset{i=1}{\overset{n}{.Math.}}.Math..Math.S.Math..Math.2.Math.i$

An oil-free screw compressor has a screw rotor including a screw and a shaft, a bearing supporting the shaft, a first shaft seal device disposed between the screw and the bearing and including a first seal opposite to the shaft, and a first communication portion communicating the bearing side with respect to between the shaft and the first seal and the outer peripheral face of the first shaft seal device, and a second shaft seal device disposed between the first shaft seal device and the bearing and including a second seal opposite to the shaft, and a second communication portion communicating the screw side with respect to between the shaft and the second seal and the outer peripheral face of the second shaft seal device. A casing includes an atmosphere communication portion connected to both of the first communication portion and the second communication portion on the inner peripheral face of a shaft accommodation space, and communicating the first communication portion and the second communication portion with the atmosphere.

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.