Abstract: A compressor system includes a first compressor, which has a first low side oil sump, in a first shell and a second compressor, which has a second low side oil sump, in a second shell. The first and second compressors are connected in series. There is an oil transfer conduit connected between the first low side sump of the first compressor and the second low side sump of the second compressor. The system also includes a normally open check valve in the oil transfer conduit. Additionally, a bleed is provided to effect oil transfer via the oil transfer conduit when the normally open valve is closed.

Abstract: A multi-rotor compressor and method of manufacturing is provided. The compressor includes a housing with a plurality of identical planet rotors. The planet rotors are equally spaced apart at a fixed distance from a centerline. A single sun rotor is provided that is disposed to cooperate with the plurality of identical planet rotors in the compression of gas. The number and radial spacing of the plurality of identical planet rotors about said single sun rotor may be arranged in different configurations to change an output capacity parameter for said compressor.

Abstract: A system and method for defrosting an air source heat pump are presented. A defrost conduit extends from the discharge from a system compressor to the outdoor coil. The defrost conduit includes a normally closed defrost valve. When the need for defrost exists, the defrost valve is opened, and warm refrigerant is delivered from the compressor discharge to the outdoor coil to effect defrost of the outdoor coil.

Abstract: A compressor system includes a first compressor, which has a first low side oil sump, in a first shell and a second compressor, which has a second low side oil sump, in a second shell. The first and second compressors are connected in series. There is an oil transfer conduit connected between the first low side sump of the first compressor and the second low side sump of the second compressor. The system also includes a normally open check valve in the oil transfer conduit. A method for effecting oil balance in a compressor system, the method includes establishing a first compressor in a first shell having a first low side oil sump and establishing a second compressor in a second shell having a second low side oil sump. The first and second compressors are connected in series. The method also includes positioning an oil transfer conduit between the first low side sump and the second low side sump and positioning a normally open check valve in the oil transfer conduit.

Abstract: A multi-rotor compressor and method of manufacturing is provided. The compressor includes a housing with a plurality of identical planet rotors. The planet rotors are equally spaced apart at a fixed distance from a centerline. A single sun rotor is provided that is disposed to cooperate with the plurality of identical planet rotors in the compression of gas. The number and radial spacing of the plurality of identical planet rotors about said single sun rotor may be arranged in different configurations to change an output capacity parameter for said compressor.

Abstract: A compressor system includes a first compressor, which has a first low side oil sump, in a first shell and a second compressor, which has a second low side oil sump, in a second shell. The first and second compressors are connected in series. There is an oil transfer conduit connected between the first low side sump of the first compressor and the second low side sump of the second compressor. The system also includes a normally open check valve in the oil transfer conduit. A method for effecting oil balance in a compressor system, the method includes establishing a first compressor in a first shell having a first low side oil sump and establishing a second compressor in a second shell having a second low side oil sump. The first and second compressors are connected in series. The method also includes positioning an oil transfer conduit between the first low side sump and the second low side sump and positioning a normally open check valve in the oil transfer conduit.

Abstract: A heat pump system and method is presented having a primary compressor, a booster compressor, an economizer, a microprocessor, an air temperature sensor, and a temperature sensor for sensing a temperature commensurate with the boiling temperature of refrigerant in the outside coil. The microprocessor effects controlled operation of the primary compressor, the booster compressor and the economizer when a thermostat calls for heat and in accordance with predetermined ranges of air temperature. The microprocessor calculates a defrost trigger temperature, and defrost operation is initiated when the sensed refrigerant boiling temperature is lower than the trigger temperature for a period of time.

Abstract: A heat pump system is presented having a primary compressor, a booster compressor, a multi-step thermostat, an indoor coil, an outdoor coil, a refrigerant flow conduit connecting these elements is a closed loop system, and at least one pressure sensor positioned to always sense the refrigerant system low side pressure, which is commensurate with outdoor ambient air temperature in all heating modes of operation. The pressure sensor functions as an override and safety control to prevent or permit operation of the compressors, and also other system components, depending on outside air temperature. The primary compressor is preferably a multi-capacity compressor. A defrost energy transfer fluid is used in a defrost cycle.

Abstract: A boosted source heat pump (BSHP) is presented having a primary compressor, a booster compressor, an economizer, and a lubricant management system. At least the primary compressor is a twin-single compressor. The lubricant management system includes traps to prevent migration of lubricant to a non-operating compressor, and aspiration tubes from the sump to the low pressure intake zone to each compressor.

Abstract: A compressor in accordance with the present invention includes a male rotor which is axially aligned with and in communication with two female rotors. The male rotor is driven by a motor, in other words the male rotor is the drive rotor. The male rotor has a plurality of lobes which intermesh with a plurality of flutes on each of the female rotors. The male rotor comprises an inner cylindrical metal shaft with an outer composite material ring mounted thereon. The ring includes the lobes of the male rotor integrally depending therefrom. The lobes of the male rotor being comprised of a composite material allows positioning of the female rotors at a small clearance from the male drive rotor. This clearance is small enough that the liquid refrigerant itself provides sufficient sealing, cooling and lubrication. The positioning of the female rotors on opposing sides of the male rotor balances the radial loading on the male rotor thereby minimizing radial bearing loads.

Abstract: A compressor in accordance with the present invention includes a male rotor which is axially aligned with and in communication with two female rotors. The compressor includes a housing and a thrust balance configuration. The thrust balance configuration includes a thrust balance disc mounted to a male rotor shaft in a discharge housing of the compressor. The thrust balance disc is exposed to fluid from the compressor at high pressure. The outside diameter of the thrust balance is sized to provide sufficient area to react thrust loads produced by the first rotor. The thrust balance configuration serves to balance the thrust loads imparted on the male rotor and allows for full axial discharge porting.

Abstract: A system for controlling the amount of foam ingested to a compressor of a cooling system is presented. The present invention utilizes a heated thermistor to control an electrically positioned expansion valve feeding liquid refrigerant to a system evaporator. The thermistor is controlled to be a few degrees warmer than the discharge saturation temperature of the refrigerant exiting the compressor. The saturation temperature corresponding to the compressor discharge pressure is calculated by a microprocessor and compared to the thermistor temperature. If the difference is greater or less than desired, the microprocessor will send the proper signals to the electrically positioned expansion valve thereby controlling the rate of foam ingested by the compressor.

Abstract: A helical-screw rotary compressor having a twin rotor configuration or a multi-rotor (i.e., at least three) configuration with defined compressor induction and discharge ends has at least one unloader piston disposed at said compressor discharge end.

Abstract: A compressor in accordance with the present invention includes a male rotor which is axially aligned with and in communication with two female rotors. The compressor includes a housing and a thrust balance configuration. The thrust balance configuration includes a stepped up portion mounted at the suction end of the male rotor and is exposed to fluid from the compressor at high pressure. The outside diameter of the thrust balance configuration is generally less than the crest diameter of the male rotor and sized to provide sufficient area to react thrust loads produced by the first rotor. The thrust balance configuration serves to balance the thrust loads imparted on the male rotor and allows for full axial discharge porting.

Abstract: A compressor with rotor unloading is presented. The compressor having a housing for supporting a multi-rotor configuration (e.g., a male rotor and two axially aligned female rotors) and a drive motor. A discharge disk is mounted at the discharge end of the male rotor. The length of the male rotor is slightly longer than the length of the female rotors, thereby providing axial clearance between the female rotors and the discharge disk. Lubrication is leaked (or flashed) through these clearances to upper bearings. The motor is supported in the compressor housing. Evaporated refrigerant from the evaporator is inducted into the compressor. The vapor phase refrigerant is compressed by the compressor. The compressed vapor phase refrigerant is then presented to a condenser, condensing the refrigerant to the liquid phase. Thereafter, liquid phase refrigerant is delivered through an expansion valve to the evaporator.

Abstract: A boosted air source heat pump system is presented having a primary compressor, a booster compressor and an economizer. On activation of the heat pump system, the primary compressor is operated. When the primary compressor cannot meet the demand, the booster compressor is activated, but only upon receipt of a signal enabling the operation of the booster compressor. The booster compressor is preferably a variable speed booster, and its speed is controlled to be at or between an absolute minimum speed and an absolute maximum speed. The booster may be on the low side or the high side of the primary compressor. The operation of the economizer may be modulated to meet the demand on the system.

Abstract: An expansion/separation compressor system is presented for a multi-rotor compressor configuration. In accordance with the present invention the rotors are disposed in a shell having open and closed off portions for providing expansion, compression and separation. The closed off portions depend from or are attached to other suitable compressor structure including the induction or discharge plates. In an embodiment the expansion portion is comprised of a sliding valve. Separation is achieved when the flute and respective open shell portion expose the fluid to basic plenum pressure. The fluid is essentially removed by centrifugal force through the opening in the shell. The compressor is mounted to an evaporator and a control system is provided to regulate the temperature of water in the evaporator thereby controlling the rate of evaporation of liquid phase refrigerant in the evaporator. The liquid phase refrigerant is expanded between the rotors and respective shell portions to a desired volume.

Abstract: A plurality of variable speed centrifugal compressors operated in parallel form an HVAC or refrigeration system. The compressors are operated at proportionally synchronized speeds throughout their range of operation.

Abstract: A primary compressor and a booster compressor connected in series is presented. A first conduit connects the low side of a heating/cooling or refrigeration system to the inlet of the booster compressor, the outlet of the booster compressor and the inlet of the primary compressor. A second conduit connects the outlet of the primary compressor to the high side of the system. The first conduit includes a check valve for closing or opening the connection between the first conduit and the outlet of the booster compressor. A sump conduit is positioned near the bottom of the primary and booster compressors to allow lubricant to flow from the booster compressor to the primary compressor.

Abstract: A boosted source heat pump (BSHP) is presented having a primary compressor, a booster compressor, an economizer, and a lubricant management system. At least the primary compressor is a twin-single compressor. The lubricant management system includes traps to prevent migration of lubricant to a non-operating compressor, and aspiration tubes from the sump to the low pressure intake zone to each compressor.