Abstract: An apparatus including a magnetic attenuator substantially surrounding a non-rotatable portion of the apparatus.

Abstract: A system and method for controlling the volume ratio of a compressor is provided. The system can use a port (88) or ports in a rotor cylinder to bypass vapor from the compression chamber to the discharge passage of the compressor. A control valve (90) can be used to open or close the port or ports to obtain different volume ratios in the compressor. The control valve (90) can be moved or adjusted by one or more valves that control a flow of fluid to the valve. A control algorithm can be used to control the one or more valves to move the control valve to obtain different volume ratios from the compressor. The control algorithm can control the one or more valves in response to operating parameters associated with the compressor.

Abstract: A compressor is provided with a substantially cylindrical housing. Inside the housing is a motor housing having a substantially cylindrical shape and a compressor housing having a substantially cylindrical shape. The motor housing and the compressor housing are connected or fit into the housing with a frictional connection to prevent axial movement of the motor housing and the compressor housing.

Abstract: An attenuating apparatus for use with a positive displacement compressor. The device includes a bore formed in a housing of the compressor, the bore being positioned at an angle to a discharge chamber of the compressor and in fluid communication with the compressor discharge chamber. A plug is positioned within the bore, the plug movable within the bore to a preselected position. The plug has a first end in contact with a gas from the compressor discharge chamber and a second, opposite end being accessible from an exterior of the housing. A seal is positioned between the plug and the bore to seal an interface between the plug and the bore to prevent leakage of a gas from the compressor discharge chamber along the interface. The plug is lockable within the bore at the preselected position.

Abstract: An attenuating apparatus for use with a positive displacement compressor. The device includes a bore formed in a housing of the compressor, the bore being positioned at an angle to a discharge chamber of the compressor and in fluid communication with the compressor discharge chamber. A plug is positioned within the bore, the plug movable within the bore to a preselected position. The plug has a first end in contact with a gas from the compressor discharge chamber and a second, opposite end being accessible from an exterior of the housing. A seal is positioned between the plug and the bore to seal an interface between the plug and the bore to prevent leakage of a gas from the compressor discharge chamber along the interface. The plug is lockable within the bore at the preselected position.

Abstract: A compressor including a compression mechanism configured and positioned to receive vapor from an intake passage and provide compressed vapor to a discharge passage. An opening is positioned in the compression mechanism in fluid communication with the discharge passage. A valve has an aperture formed therein, the aperture configured and positioned in fluid communication with a passageway to provide a path for a pressurized vapor flow to a first chamber and a first piston without mixing with vapor in the discharge passage. A second chamber is in fluid communication with a second piston and the discharge passage, the first piston and the second piston of the valve configured to move together. First piston and second piston movement are controllable in response to predetermined conditions to maintain the magnitude of pressure of the compression mechanism immediately upstream of the opening at substantially the same pressure magnitude at the discharge passage.

Abstract: A system is provided for maintaining the position of a valve in a compressor. The valve includes a valve body connected to a piston in a cylinder by a shaft. The valve body is positioned in the discharge outlet of the compressor based on the location of the piston in the cylinder. The system maintains the position of the valve body in response to a movement of the piston by permitting fluid to flow from a fluid source through the piston and into a chamber of the cylinder to urge the piston back to its initial position in the cylinder.

Abstract: A backflow and strainer device is presented. The device is a unitary unit that prevents backflow of fluid gas in a compressor and prevents dirt particles and debris from entering the compressor, thereby damaging the components. A valve mechanism moves between an open position and a closed position to either allow or prevent fluid gas from flowing into the compressor. A mesh portion is disposed in the device to trap all dirt particles and debris to prevent them from entering the compressor. The valve mechanism responds to the higher and lower pressures associated with the operation and shutdown of compressors.

Abstract: A screw compressor with a volume ratio adjustment mechanism. The volume adjustment mechanism is a penetration in the housing of a screw compressor. The penetration includes one or more apertures. The apertures provide a flow path between the compressor outlet and an interlobe region of the screw compressor rotors. A member resides in the penetration and is movable from a first position in which the apertures are blocked and the flow path is closed and a second position in which the apertures are not blocked and the flow path is open. By unblocking the apertures and opening the flow path, the volume ratio can be adjusted.

Abstract: Screw chillers have economizer systems that include a low pressure economizer and a high pressure economizer. According to certain embodiments, the low pressure economizer includes a flash tank, an expansion device and a flow control valve while the high pressure economizer includes a heat exchanger and an expansion device. The screw chillers also include a screw compressor that compresses refrigerant. The screw compressor includes a low pressure economizer port designed to receive lower pressure refrigerant from the flash tank within the low pressure economizer and a high pressure economizer port designed to receive higher pressure refrigerant from the heat exchanger within the higher pressure economizer. The screw compressor is designed to compress the refrigerant received from the evaporator, the refrigerant received through the low pressure economizer port, and the refrigerant received through the high pressure economizer port and to discharge the refrigerant through a common discharge.

Abstract: A system is provided for adjusting the volume ratio of a screw compressor. The system can use a port in a rotor cylinder to bypass vapor from the compression chamber to the discharge passage of the compressor. A valve can be used to open or close the port to obtain different volume ratios in the compressor.

Abstract: A system for cancelling or attenuating noise in at least two positive displacement compressors proximately located from each other for use with a heating or cooling system. A lead compressor and a lag compressor have a controllable rotational speed and phase of operation. A controller selectably controls the rotational speed and the phase of operation of each of the compressors. The controller controls the rotational speed of the compressors at substantially the same speed for each compressor, with a phase-lock loop and a comparator circuit for each compressor. The controller controls the phase of operation of the compressors through an oscillator so that the lead and lag compressor pressure pulses are spaced between successive outlet pressure pulses to effectively double the combined pulsation frequency for noise attenuation.

Abstract: A system is provided for controlling the balance piston pressure in a screw compressor. The system can use the slide valve of the compressor as a valve to control the flow of fluid from a fluid source to the balance piston. When the slide valve prevents direct flow between the fluid source and the balance piston, an alternate path is used to provide fluid at a reduced pressure to the balance piston. The reduced pressure fluid is obtained by passing the fluid from the fluid source through an orifice to lower the fluid pressure.

Abstract: A compressor is provided with a substantially cylindrical housing. Inside the housing is a motor housing having a substantially cylindrical shape and a compressor housing having a substantially cylindrical shape. The motor housing and the compressor housing are connected or fit into the housing with a frictional connection to prevent axial movement of the motor housing and the compressor housing.

Abstract: A system is provided for maintaining the position of a valve in a compressor. The valve includes a valve body connected to a piston in a cylinder by a shaft. The valve body is positioned in the discharge outlet of the compressor based on the location of the piston in the cylinder. The system maintains the position of the valve body in response to a movement of the piston by permitting fluid to flow from a fluid source through the piston and into a chamber of the cylinder to urge the piston back to its initial position in the cylinder.

Abstract: A system is provided for attenuating tonal acoustic noise associated with a single positive displacement compressor, or multiple positive displacement compressors proximately located from each other. A controller selectably controls the rotational speed and the frequency of operation of each of the compressors. The controller controls the rotational speed of the compressors about a predetermined rotational speed, in a random manner, within the pre-selected speed band to reduce the magnitude of the central tonal acoustic frequency of the pressure pulsations and disperse the sound power over a wider acoustic bandwidth.

Abstract: A system for cancelling or attenuating noise in at least two positive displacement compressors proximately located from each other for use with a heating or cooling system. A lead compressor and a lag compressor have a controllable rotational speed and phase of operation. A controller selectably controls the rotational speed and the phase of operation of each of the compressors. The controller controls the rotational speed of the compressors at substantially the same speed for each compressor, with a phase-lock loop and a comparator circuit for each compressor. The controller controls the phase of operation of the compressors through an oscillator so that the lead and lag compressor pressure pulses are spaced between successive outlet pressure pulses to effectively double the combined pulsation frequency for noise attenuation.

Abstract: A system is provided for attenuating noise in at least two positive displacement compressors proximately located from each other for use with at least one heating or cooling system. A lead compressor and a lag compressor have a selectably controllable rotational speed and a selectably controllable phase of operation. A controller selectably controls the rotational speed and the phase of operation of each of the compressors. The controller controls the rotational speed of the compressors at a predetermined rotational speed that is substantially the same for each of the compressors. The controller controls the phase of operation of the compressors by shifting the phase of operation of the lag compressor so that an outlet pressure pulse operatively produced by the lag compressor is substantially evenly spaced between successive outlet pressure pulses operatively produced by the reference compressor.

Abstract: A backflow and strainer device is presented. The device is a unitary unit that prevents backflow of fluid gas in a compressor and prevents dirt particles and debris from entering the compressor, thereby damaging the components. A valve mechanism moves between an open position and a closed position to either allow or prevent fluid gas from flowing into the compressor. A mesh portion is disposed in the device to trap all dirt particles and debris to prevent them from entering the compressor. The valve mechanism responds to the higher and lower pressures associated with the operation and shutdown of compressors.

Abstract: A system is provided for attenuating tonal acoustic noise associated with a single positive displacement compressor, or multiple positive displacement compressors proximately located from each other. A controller selectably controls the rotational speed and the frequency of operation of each of the compressors. The controller controls the rotational speed of the compressors about a predetermined rotational speed, in a random manner, within the pre-selected speed band to reduce the magnitude of the central tonal acoustic frequency of the pressure pulsations and disperse the sound power over a wider acoustic bandwidth.