A scroll compressor may include an orbiting scroll; a non-orbiting scroll engaged with the orbiting scroll to form a pair of compression chambers between the orbiting scroll and the non-orbiting scroll; a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber to support the non-orbiting scroll toward the orbiting scroll; a first back pressure passage that connects a first intermediate pressure chamber in the compression chamber and the back pressure chamber; a second back pressure passage that connects a second intermediate pressure chamber having a higher pressure than the first intermediate pressure chamber and the back pressure chamber; and a back pressure control valve configured to selectively open and close the first back pressure passage and the second back pressure passage according to an operation mode. The back pressure control valve moves to a first position at which the first back pressure passage is open and the second back pressure passage is closed in a power operation, and moves to a second position at which the first back pressure passage is closed and the second back pressure passage is open in a saving operation.

A scroll compressor includes a housing and a compression mechanism. The compression mechanism includes a compression chamber. The housing includes an intermediate pressure chamber into which refrigerant having an intermediate pressure is introduced from an external refrigerant circuit. The intermediate pressure is higher than a suction pressure of refrigerant drawn into the compression chamber and lower than a discharge pressure of the refrigerant discharged from the compression chamber. The intermediate pressure chamber and the compression chamber in a process of compression are connected to each other by an injection passage. The injection passage includes a muffler.

A system for operational acoustic optimization of a variable speed compressor (2) includes a motor (6), a frequency inverter (3), and a control block (5). The frequency inverter (3) is electrically connected to the synchronous motor (6), an electrical network (4), and the control block (5). The control block (5) is configured to control the speed of the motor (6) and to establish a first switching frequency (F1) and a second switching frequency (F2) of the frequency inverter (3). The frequency inverter (3) is configured to start the variable speed compressor (2) by supplying motor (6) with a signal (9) with the first switching frequency (F1) for the duration of a time period (T1) corresponding to at least one alignment operation period of the motor (6) and to supply the motor (6) with a signal (9) with the second switching frequency (F2) after the time period (T1).

A compressor includes a first throttle portion that receives a refrigerant at an intermediate pressure from an injection pipe of a refrigerant circuit, an enlarged flow path portion that receives the refrigerant from the first throttle portion, a second throttle portion that receives the refrigerant from the enlarged flow path portion, and a compression element. The compression element includes a compression chamber that receives the refrigerant from the second throttle portion. The first throttle portion has a flow path cross-sectional area that is narrower than both a flow path cross-sectional area of the injection pipe and a flow path cross-sectional area of the enlarged flow path portion. The second throttle portion has a flow path cross-sectional area that is narrower than the flow path cross-sectional area of the enlarged flow path portion.

An electronics for active cancellation of a pulsating flow with a source noise reference. The electronics includes a signal processor configured to receive a noise source signal and a flow signal. The signal processor is also configured to generate a cancelling signal based on the noise source signal and the flow signal. A controller is communicatively coupled to the signal processor, and configured to determine a flow rate control signal for controlling the flow rate of the pulsating flow. A signal generator coupled to the signal processor and the controller is configured to receive the flow rate control signal, generate a valve signal based on the flow rate control signal and the cancelling signal, and provide the valve signal to a valve to control the flow rate and attenuate the one or more pulses of the pulsating flow.

A system for noise and vibration management of a smoke evacuation system includes a pump that compresses air and produces a pressure differential within an airflow path. The pump may be a sealed, positive displacement pump. The system includes vibration absorption mechanisms disposed between inner and outer housings, as well as on the outside surface of the outer housing. Methods of controlling and regulating a motor of the system to preserve the lifespan of the motor and maintain consistent airflow rates throughout the smoke evacuation system include varying a supply of electrical current to the motor so that it can operate at variable performance levels. Orifices are opened and closed in order to relieve resistance pressures within the airflow path due to clogging and blockages.

A scroll compressor includes a housing and a compression mechanism. The compression mechanism includes a compression chamber. The housing includes an intermediate pressure chamber into which refrigerant having an intermediate pressure is introduced from an external refrigerant circuit. The intermediate pressure is higher than a suction pressure of refrigerant drawn into the compression chamber and lower than a discharge pressure of the refrigerant discharged from the compression chamber. The intermediate pressure chamber and the compression chamber in a process of compression are connected to each other by an injection passage. The injection passage includes a muffler.

A balancing mechanism for a positive displacement machine, in particular a scroll compressor, wherein the balancing mechanism includes a drive shaft, a first balancing element and a second balancing element. The first balancing element includes a cylindrical hub section and a first force transmission section and is rotatably in contact with the drive shaft via a first axis of rotation. The second balancing element is rotatably in contact with the drive shaft via a second axis of rotation. A center axis S of the drive shaft and a center axis C of the cylindrical hub section are arranged on a first reference line CS, and a center of gravity J of the first balancing element and a center of gravity K of the second balancing element are arranged on a different side of the first reference line CS than a center axis P of the first axis of rotation.

A scroll compressor includes a housing and a compression mechanism. The compression mechanism includes a compression chamber. The housing includes an intermediate pressure chamber into which refrigerant having an intermediate pressure is introduced from an external refrigerant circuit. The intermediate pressure is higher than a suction pressure of refrigerant drawn into the compression chamber and lower than a discharge pressure of the refrigerant discharged from the compression chamber. The intermediate pressure chamber and the compression chamber in a process of compression are connected to each other by an injection passage. The injection passage includes a muffler.

An electrically-driven compressor is installed in an engine. Refrigerant is compressed with rotation of a rotating shaft in a compression unit. An electric motor is coupled to the rotating shaft and drives the compression unit through the rotating shaft. A housing accommodates the compression unit, the electric motor, and the motor drive circuit aligned in the listed order in the axial direction of the rotating shaft. The housing is internally provided with the discharge chamber through which the refrigerant compressed by the compression unit is discharged. The weight is attached to the housing and disposed in the discharge chamber in a manner that a resonance frequency of the electrically-driven compressor is shifted relative to a resonance frequency of the engine, the weight including a material having a specific gravity greater than a specific gravity of a constituent material of the housing.