A vacuum pump system comprising a main vacuum pump that is connected to a chamber that is to be evacuated. An auxiliary pump is connected to an outlet of the main vacuum pump. Furthermore, a sealing gas supply device is connected to the main vacuum pump. The sealing gas supply device is switched on and off with the aid of a control device as a function of a predetermined control variable. Additionally, a method for controlling the vacuum pump system.

A screw compressor (10) comprising a compressor device (18), in particular, at least one screw rotor (20, 22), which guides a compressed medium to an oil separating device (30). The compressor (10) has a first volume (32) and a second volume (34), in addition to a separating device (36) separating the first and the second volumes (32, 34) from each other. The first volume (32) is defined by a housing inner wall (52) and the separating device (36) which separates the first volume (32) from the second volume (34). The separating device (36) comprises a demistor (40) and an oil discharging device (54) is arranged on the separating device (36).

A screw compressor (10) comprising a compressor device (18), in particular, at least one screw rotor (20, 22), which guides a compressed medium to an oil separating device (30). The compressor (10) has a first volume (32) and a second volume (34), in addition to a separating device (36) separating the first and the second volumes (32, 34) from each other. The first volume (32) is defined by a housing inner wall (52) and the separating device (36) which separates the first volume (32) from the second volume (34). The separating device (36) comprises a demistor (40) and an oil discharging device (54) is arranged on the separating device (36).

A tip seal for scroll wraps in a scroll compressor is provided. The tip seal may include surface features to form a tortuous flow path in a seal groove of a scroll wrap. The surface features can help form one or more contraction and/or expansion areas in the tortuous flow path. The tortuous flow path can help provide resistance to fluid flow and help reduce leakage through the seal groove.

Liquid Ring pumps are inherently inefficient due to energy losses caused by friction, the present invention overcomes this by providing a coating on certain surfaces of the pump to limit the friction.

Liquid Ring pumps are inherently inefficient due to energy losses caused by friction, the present invention overcomes this by providing a coating on certain surfaces of the pump to limit the friction.

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. $S1S2=\underset{i=1}{\overset{n}{.Math.}}S2i$

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. $S1S2=\underset{i=1}{\overset{n}{.Math.}}S2i$

A compressor includes: a casing with an inner wall defining a compression chamber, an inlet leading into the compression chamber, and an outlet leading out of the compression chamber; a rotor rotatably coupled to the casing for rotation relative to the casing; and a gate coupled to the casing for movement relative to the casing. The gate may be pivotally, or translationally coupled to the casing. A hydrostatic bearing may be disposed between the gate and casing. A plurality of compressors may be mechanically linked together such that their compression cycles are out of phase.

A compressor includes: a casing with an inner wall defining a compression chamber, an inlet leading into the compression chamber, and an outlet leading out of the compression chamber; a rotor rotatably coupled to the casing for rotation relative to the casing; and a gate coupled to the casing for movement relative to the casing. The gate may be pivotally, or translationally coupled to the casing. A hydrostatic bearing may be disposed between the gate and casing. A plurality of compressors may be mechanically linked together such that their compression cycles are out of phase.