An object of the present invention is to provide a rotary displacement compressor capable of determining whether a check valve has failed, and preventing the life of a compressor body from being reduced when a compression operation stops. In order to achieve the object, a rotary displacement compressor includes a compressor body that compresses a medium by reducing a volume of the medium using rotation; a discharge pipe through which a compressed medium, which is discharged through a discharge port of the compressor body, flows; a check valve that shuts off the compressed medium flowing backward to the compressor body; and a backflow control valve that allows a predetermined rate of the compressed medium to flow backward. The check valve and the backflow control valve are disposed in series via the discharge pipe.

An object of the present invention is to provide a rotary displacement compressor capable of determining whether a check valve has failed, and preventing the life of a compressor body from being reduced when a compression operation stops. In order to achieve the object, a rotary displacement compressor includes a compressor body that compresses a medium by reducing a volume of the medium using rotation; a discharge pipe through which a compressed medium, which is discharged through a discharge port of the compressor body, flows; a check valve that shuts off the compressed medium flowing backward to the compressor body; and a backflow control valve that allows a predetermined rate of the compressed medium to flow backward. The check valve and the backflow control valve are disposed in series via the discharge pipe.

A vacuum pump for supplying a machine assembly with negative pressure, the vacuum pump including a housing featuring a delivery chamber which includes a chamber inlet opening and a chamber outlet opening for a gaseous fluid; a suction port for establishing a fluid connection to the machine assembly; a suction channel which connects the delivery chamber to the suction port; and a relief channel which connects the delivery chamber to a relief opening of the housing; a delivery member which can rotate in the delivery chamber in a forward rotational direction and a reverse rotational direction. The fluid is suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in the forward rotational direction.

Methods and systems for detecting and correcting improper operation of a compressor in a refrigeration system and/or an HVAC system include a component level detection and prevention and a system level detection and prevention. The system level detection and prevention can be a backup or a confirmation of the component level detection and prevention. The component level detection and prevention can detect and prevent improper compressor operation within a predetermined time so that the compressor's operation period in an improper direction can be minimized, thereby minimizing wear and damage to the compressor.

Methods and systems for detecting and correcting improper operation of a compressor in a refrigeration system and/or an HVAC system include a component level detection and prevention and a system level detection and prevention. The system level detection and prevention can be a backup or a confirmation of the component level detection and prevention. The component level detection and prevention can detect and prevent improper compressor operation within a predetermined time so that the compressor's operation period in an improper direction can be minimized, thereby minimizing wear and damage to the compressor.

The fluid transfer apparatus includes a rotor housing for forming a fluid compression space having the shape of an epitrochoid surface; a rotor eccentrically rotates inside the fluid compression space by being eccentrically coupled to a rotation shaft; and a rotor housing cover covering the fluid compression space of the rotor housing and including a rotation shaft penetration hole formed at the center of the cover, and a first cover fluid channel and second cover fluid channel are symmetrically formed on the opposite sides of each other with the rotation shaft penetration hole in the middle, wherein a plurality of rotor housing covers are arranged to be spaced apart from each other, one rotor housing is arranged between every two rotor housing covers, one rotor is arranged in the fluid compression space of each rotor housing, and each rotor is arranged to face a different direction from a neighboring rotor.

An electric compressor system for a vehicle includes: an electric motor having a rotor and a motor shaft which selectively rotate in a first rotation direction or a second rotation direction; an external rotation shaft extending from the motor shaft of the electric motor; a first compressor unit connected to the external rotation shaft and selectively compressing a first fluid according to the rotation direction of the external rotation shaft; and a second compressor unit connected to the external rotation shaft and selectively compressing a second fluid according to the rotation direction of the external rotation shaft, wherein the first compressor unit and the second compressor unit are sequentially arranged on the external rotation shaft, the first compressor unit is fluidly connected to a first fluid system, and the second compressor unit is fluidly connected to a second fluid system.

A system includes a refrigerant compressor, an electric motor and configured to drive the refrigerant compressor, and a controller. The controller is configured to operate the compressor in a liquid clearing start mode where electrical current through the motor is prevented from exceeding a predetermined current limit for a period of time not to exceed a predetermined period of time, and is configured to operate the compressor in a run mode in response to determining the motor exceeds a predetermined speed threshold at or before expiration of the predetermined period of time, wherein the run mode does not prevent electrical current through the motor from exceeding said predetermined current limit.

A system includes a refrigerant compressor, an electric motor and configured to drive the refrigerant compressor, and a controller. The controller is configured to operate the compressor in a liquid clearing start mode where electrical current through the motor is prevented from exceeding a predetermined current limit for a period of time not to exceed a predetermined period of time, and is configured to operate the compressor in a run mode in response to determining the motor exceeds a predetermined speed threshold at or before expiration of the predetermined period of time, wherein the run mode does not prevent electrical current through the motor from exceeding said predetermined current limit.

A device for compressing and expanding gases, wherein the device comprises an apparatus that can be driven in two directions, whereby in one direction the apparatus operates to compress a gas and in the other direction the apparatus operates to expand a gas.