A package-type air-cooled screw compressor has a compressor body relating to an air-cooled screw compressor, a drive motor, a package that houses the compressor body and the drive motor, an intake opening that takes in an air that cools the compressor body and the drive motor, an exhaust opening that exhausts the air, a duct extended downward from the exhaust opening, to transport the air to the exhaust opening, and an exhaust fan that exhausts the air. A lower end of a wall face constituting the duct is extended downward so that a lower-end inlet of the duct is placed at a position not viewable from a center position of the compressor body.

A compressor unit includes a compressor, an electric motor which is lined with the compressor along the horizontal direction and drives the compressor, and a sound shielding member which reduces noise generated by the compressor. The sound shielding member has a shape of surrounding the compressor on a first side, a second side and a third side of the compressor and exposing the electric motor, the first and second sides being in a depth direction perpendicular to a lined direction in which the compressor and the electric motor are lined, and the third side being opposite to another side of the compressor where the electric motor is located in the lined direction.

A phase change compressor cover may include a first layer configured to provide sound attenuation from undesirable noise produced as a result of operating a compressor and/or thermal isolation of the compressor and a second layer comprising a cavity filled with a phase change material that is configured to absorb heat discharged as a result of operating the compressor and subsequently discharge the absorbed heat onto the compressor in response to discontinuing operation of the compressor to keep the compressor warm and prevent refrigerant migration to the compressor. The phase change compressor cover may be used to substantially envelope the compressor in a heat pump heating, ventilation, and/or air conditioning (HVAC) system.

An electric vehicle vacuum pump assembly includes a combination, a separate acoustic barrier casing configured to encase the combination in each of a radially-spaced relationship and an axially-spaced relationship, and an annular gastight attenuation assembly radially arranged between the separate acoustic barrier casing on a first side and the combination on a second side. The combination comprises a pump unit and a drive motor comprising a rotor space, a stator space, a ventilation inlet, and a ventilation outlet. The rotor space comprises a motor rotor, and the stator space comprises a motor stator. The separate acoustic barrier casing comprises an intake connection and a discharge connection. The ventilation inlet and the ventilation outlet of the drive motor are configured to provide a forced ventilation past the annular gastight attenuation assembly and through at least one of the rotor space and the stator space.

On a plane orthogonal to the rotation shaft, an upper muffler chamber has a plurality of flared portions that are flared from a center of a rotation shaft toward between penetrating bolts and a plurality of small-diameter portions that connect between the flared portions, are apart from penetrating bolts, and are formed on a center side of the rotation shaft from the penetrating bolts. A muffler outlet is provided in each flared portion. A second outlet and a refrigerant path hole of an upper end plate are positioned on an inside of one of a plurality of flared portions, and an opening area of the muffler outlet of one flared portion is greater than an opening area of the muffler outlet of each of the other flared portions.

On a plane orthogonal to the rotation shaft, an upper muffler chamber has a plurality of flared portions that are flared from a center of a rotation shaft toward between penetrating bolts and a plurality of small-diameter portions that connect between the flared portions, are apart from penetrating bolts, and are formed on a center side of the rotation shaft from the penetrating bolts. A muffler outlet is provided in each flared portion. A second outlet and a refrigerant path hole of an upper end plate are positioned on an inside of one of a plurality of flared portions, and an opening area of the muffler outlet of one flared portion is greater than an opening area of the muffler outlet of each of the other flared portions.

A shunt pulsation trap for a scroll compressor reduces gas pulsations, NVH and improves off-design efficiency. Generally, a scroll compressor with the shunt pulsation trap has a pair of orbiting and stationary scrolls for forming a compression chamber that moves gas pockets from a suction port to a discharge port with internal compression. The shunt pulsation trap is configured to trap and attenuate as pulsations before the discharge port and comprises a pulsation trap chamber adjacent to the compression chamber, therein housed various gas pulsation dampening means or gas pulsation containment means, at least one trap inlet port branching off from the compression chamber into the pulsation trap chamber and a trap outlet port communicating with the compressor discharge chamber after the discharge port.