An expansion chamber for a rotary vane vacuum pump is provided. The expansion chamber is in fluid communication with the discharge side of the rotary vane vacuum pump, such that the expansion chamber attenuates sound as a Helmholtz resonator. The expansion chamber includes an internal volume of between 80 cubic centimeters and 100 cubic centimeters, inclusive, and includes a curved sidewall that extends partially around, and generally conforms to, the exterior of the rotary vane vacuum pump. The expansion chamber also includes a downward extending port, open to the atmosphere, for attachment to a hose in applications in which the expansion chamber is below a water line.

In order to further improve the sound damping in a refrigerant compressor comprising a common housing, a screw-type compressor in a common housing has a compressor housing that is formed as part of the common housing with a first sound absorber unit which is arranged in the common housing. The first sound absorber unit is arranged adjacent a housing window, and the sound absorber unit comprises at least one chamber which is located between an inlet opening and an outlet opening and which widens out relative to the inlet opening and to the outlet opening in a direction transverse to a direction of flow.

A screw compressor having screw rotors for compressing a process gas, a pipe bend conducting compressed process gas towards a silencer. The pipe bend at an inlet-side portion comprises a first connecting piece fastening the pipe bend to a pressure port and on an outlet-side portion a second connecting piece for fastening the pipe bend to the silencer. The pipe bend has a flow channel between the connecting pieces defined by an inner wall and an insert that projects into the inlet-side portion of the pipe bend. An outer wall of the insert projecting into the flow channel of the pipe bend and a portion of the inner wall of the pipe bend enclosing this outer wall on the outside delimit a space acting as resonator, coupled to the flow channel of the pipe bend.

A compressor includes a compression mechanism to compress gas and discharge compressed gas, an electric motor to drive the compression mechanism, a casing housing the compression mechanism and the electric motor, a suction pipe connected to a suction side of the compression mechanism via the casing, and a discharge pipe provided at the casing to open in a space in the casing. The space has a first space located below the motor, and a second space located above the motor. The compression mechanism is disposed in the first space. The compressor is provided with a partition plate disposed in the second space, and the having a gas passage hole. The partition plate further has an oil drain hole formed at a lower level than an open end of the gas passage hole, and located radially outside an outer peripheral surface of a rotor of the electric motor.

A vacuum pump comprises rotor elements arranged in a suction chamber. An outlet duct is connected to an exhaust pipe. For the purpose of silencing, sound expansion spaces are provided in the outlet duct, which are integrated into the pump housing. Alternatively or in addition to these sound expansion spaces, sound expansion spaces may be provided in an inlet duct which is used for the inlet of gas ballast, said sound expansion spaces being preferably likewise integrated into the pump housing.

It is intended to provide a vacuum pump so that without upsizing the vacuum pump, noise and vibration are reduced, heat dissipation property is secured, and the casing is downsized. Therefore, at least one turning part is provided in an exhausting path formed in a casing body. The casing body is formed of a material whose thermal conductivity is higher than that of a rotor and vanes, and a cylinder part where the vanes slide is press fitted in the casing body.

The disclosure relates to a compressor having a noise reduction resonator. The compressor includes: a compression part having compression space in which introduced gas is accommodated, and configured to compress and discharge the gas in the compression space; and a gas moving part having an inner wall forming a gas flow path through which the gas discharged from the compression space moves, wherein the gas moving part is provided with a first resonator configured to communicate with the gas flow path on the inner wall forming the gas flow path and having a resonance space depressed upward in a moving direction of the gas. The compressor according to the disclosure may prevent compression efficiency from decreasing and maintain a noise reduction effect for a long period of time by preventing foreign objects or liquids from being accumulated in the resonance space.

An expansion chamber for a rotary vane vacuum pump is provided. The expansion chamber is in fluid communication with the discharge side of the rotary vane vacuum pump, such that the expansion chamber attenuates sound as a Helmholtz resonator. The expansion chamber includes an internal volume of between 80 cubic centimeters and 100 cubic centimeters, inclusive, and includes a curved sidewall that extends partially around, and generally conforms to, the exterior of the rotary vane vacuum pump. The expansion chamber also includes a downward extending port, open to the atmosphere, for attachment to a hose in applications in which the expansion chamber is below a water line.

Disclosed is a discharge muffler for a compressor constructed as an inner duct extending inside an outer duct, the inner duct being open at each end and the outer duct being open only at the muffler inlet. The inner duct has a plurality of holes communicating with the outer duct. At least two of the holes are at different distances from the muffler outlet.

A rotary compressor includes: a shell defining an internal space; a driving motor arranged in the internal space of the shell; and a compression mechanism unit to receive power of the driving motor and compress refrigerant, wherein the compression mechanism unit includes: a cylinder defining a chamber in which the refrigerant is compressed; a rotary shaft connected to the driving motor; a roller located in the chamber and connected to the rotary shaft to compress the refrigerant in the chamber while being rotated; a bearing coupled to the cylinder and having a discharge port through which the refrigerant compressed in the chamber passes; a muffler coupled to the bearing and into which the refrigerant passing through the discharge port is introduced; and a noise reducing unit fixed to the muffler to define a noise reducing chamber together with the muffler.