Abstract: An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

Abstract: A volume ratio control system for a compressor includes a chamber formed within a housing of the compressor, where the chamber is in fluid communication with a high pressure side of the compressor, a piston disposed within the chamber, where the piston includes a cavity in fluid communication with a low pressure side of the compressor, and a biasing device disposed within the chamber and configured to enable movement of the piston in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value.

Abstract: A volume ratio control system for a compressor includes a chamber formed within a housing of the compressor, a piston disposed within the chamber, where the piston is configured to separate the chamber into at least a first portion fluidly coupled to a low pressure side of the compressor and a second portion fluidly coupled to a high pressure side of the compressor, and a biasing device disposed within the chamber, where the biasing device is configured to adjust a position of the piston in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value.

Abstract: An economizer control system includes a compressor including a compression area, a piston chamber, and an economizer inlet configured to receive economizer vapor into the compression area via a flow path that extends between the economizer inlet and the compression area. At least a portion of the flow path traverses the piston chamber. The economizer control system also includes a piston disposed within the piston chamber and configured to contact the economizer vapor. The piston is moveable between an open position that opens the flow path and a closed position that closes the flow path. Additionally, the economizer control system includes a biasing system configured to apply force to the piston to bias the piston toward the closed position.

Abstract: A compressor and method for controlling the volume ratio of a compressor is provided. The compressor includes a an intake passage, a discharge passage and a compression mechanism, the compression mechanism being positioned to receive vapor from the intake passage and provide compressed vapor to the discharge passage. At least one opening is positioned in the compression mechanism to bypass a portion of the vapor in the compression mechanism to the discharge passage, the at least one opening being sized and positioned to automatically vary a volume ratio in the compressor in response to a varying pressure differential between the intake passage and the discharge passage.

Abstract: A semi-hermetic compressor for ammonia service includes a compressor portion and a motor encased in an airtight housing portion. The compressor portion compresses ammonia. The motor includes a stator winding. Motor leads are connected to the field windings, and extend from the housing portion through a pass-through assembly. The pass-through assembly includes a base portion, a first isolation portion, a second isolation portion, a sealant and a cap portion. The base portion is inserted into the housing portion with an airtight seal. The first isolation portion is arranged to fit within an annular opening in the base portion. First and second isolation portions include apertures for a motor lead. Sealant is disposed between the isolation portions. A cap portion attaches to the base portion. An anti-rotation element prevents relative rotation there between.

Abstract: A compressor and method for controlling the volume ratio of a compressor is provided. The compressor includes a an intake passage, a discharge passage and a compression mechanism, the compression mechanism being positioned to receive vapor from the intake passage and provide compressed vapor to the discharge passage. At least one opening is positioned in the compression mechanism to bypass a portion of the vapor in the compression mechanism to the discharge passage, the at least one opening being sized and positioned to automatically vary a volume ratio in the compressor in response to a varying pressure differential between the intake passage and the discharge passage.

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 variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to make the motor stronger or weaker to compensate for varying conditions in the HVAC&R system. The VSD and corresponding control system or algorithm can monitor an operating parameter of the HVAC&R system, such as the kW absorbed by the motor, and then raise or lower the V/f of the VSD to obtain the lowest possible power consumption from the motor.

Abstract: A variable-efficiency screw compressor for use in a closed-loop system configured to perform refrigeration is provided. The variable-efficiency screw compressor includes an inlet port to draw refrigerant into the variable-efficiency screw compressor, one or more rotating screws in fluid communication with the inlet port to compress the refrigerant, forming a compressed refrigerant, a discharge port in fluid communication with the rotating screws to receive the compressed refrigerant and discharge the refrigerant, wherein the discharge port includes an adjustable piston movable within the discharge port from a first position in which volume is higher to a second position in which volume is lower, the adjustable piston arranged and disposed to adjust volume of the discharge port in response to a change in demand.

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: A semi-hermetic compressor for ammonia service includes a compressor portion and a motor encased in an airtight housing portion. The compressor portion compresses ammonia. The motor includes a stator winding. Motor leads are connected to the field windings, and extend from the housing portion through a pass-through assembly. The pass-through assembly includes a base portion, a first isolation portion, a second isolation portion, a sealant and a cap portion. The base portion is inserted into the housing portion with an airtight seal. The first isolation portion is arranged to fit within an annular opening in the base portion. First and second isolation portions include apertures for a motor lead. Sealant is disposed between the isolation portions. A cap portion attaches to the base portion. An anti-rotation element prevents relative rotation there between.

Abstract: A variable capacity screw compressor for use in a refrigeration system is provided. Compressed refrigerant gas from the compressor is expelled into a discharge port in fluid communication with the refrigeration circuit. The volume associated with the discharge port can be periodically varied, allowing the efficiency of the compressor to be varied periodically. The discharge port volume includes a penetration that houses a movable member or plug that permits the volume to be periodically varied. This movable member is accessible from the exterior of the compressor housing to adjust the position of the movable member within the discharge port volume. The movable member may be adjusted to a full open position in which the discharge port volume is maximized, to a full closed position in which the discharge port volume is minimized, and to any position between full open and full closed.

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 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 variable-efficiency screw compressor for use in a closed-loop system configured to perform refrigeration is provided. The variable-efficiency screw compressor includes an inlet port to draw refrigerant into the variable-efficiency screw compressor, one or more rotating screws in fluid communication with the inlet port to compress the refrigerant, forming a compressed refrigerant, a discharge port in fluid communication with the rotating screws to receive the compressed refrigerant and discharge the refrigerant, wherein the discharge port includes an adjustable piston movable within the discharge port from a first position in which volume is higher to a second position in which volume is lower, the adjustable piston arranged and disposed to adjust volume of the discharge port in response to a change in demand.

Abstract: A variable speed drive (VSD) can be used to vary the voltage-to-frequency ratio (V/f) supplied to a compressor motor of a heating, ventilation, air conditioning or refrigeration (HVAC&R) system to make the motor stronger or weaker to compensate for varying conditions in the HVAC&R system. The VSD and corresponding control system or algorithm can monitor an operating parameter of the HVAC&R system, such as the kW absorbed by the motor, and then raise or lower the V/f of the VSD to obtain the lowest possible power consumption from the motor.

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: 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.