Abstract: A variable capacity vapor compression cooling system is presented. In the system of the present invention, air conditioning requirements are entered into a microprocessor which controls the system. Liquid phase refrigerant entering an evaporator is regulated by a microprocessor controlled electronic expansion valve. Evaporated refrigerant is delivered to a pair of compressors from the evaporator. The motors for the compressors are controlled by a controller. Each of the compressors has a feed back loop attached thereto for feeding back some of the inducted vapor phase refrigerant. The amount of vapor fed back in each loop is regulated by a corresponding microprocessor controlled multi-purpose valve. The compressed vapor phase refrigerant is then presented to a condenser which condenses the refrigerant to the liquid phase which is used for cooling, as is well known in the art. Thereafter, liquid phase refrigerant is presented to an economizer where vapor phase refrigerant (i.e., flash gas) is drawn off.

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 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 with an economizer injection port therein. The unloader pistons being opened and closed in fine discrete steps by microprocessor controlled stepping motors which drive linear actuators.

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: Loss of oil due to oil feedback is prevented in a screw compressor in a refrigeration application due to low capacity operation. The apparent suction temperature is compared to the temperature of the water exiting the evaporator to determine the apparent superheat and the loading is increased upon the apparent superheat reaching a predetermined level. Upon sensing a predetermined difference, an electronic slide valve block is initiated to prevent further unloading and loading may be initiated in a fixed amount, incrementally or on a pulsed basis.

Abstract: Oil laden refrigerant is supplied tangentially into an oil separator for a primary removal of oil and then into a coalescer for a secondary removal of oil. Flow between the oil separator and coalescer is controlled by a valve so as to insure that a rapid build up of pressure takes place in the sump to insure adequate lubrication to the compressor.

Abstract: A refrigeration system includes a rack or bank of compressors located in parallel and feeding a common condenser. Liquid refrigerant from the condenser is supplied to a plurality of evaporators located in parallel and feeding a common suction manifold. The suction manifold is connected to the compressors and contains a valve for selectively isolating one or more compressors and evaporators whereby the isolated compressor acts as a satellite compressor and the isolated evaporators are operated at a lower temperature than the other evaporators.

Abstract: An economizer is connected to a fluid line connecting the booster compressor and high stage compressor of a refrigeration system at a point downstream of the bypass for unloading the booster compressor. The economizer flow controls the discharge temperature of the second stage and, in addition, coacts with the bypassing of the booster compressor such that all of the flow supplied to the high stage is at system suction pressure when the bypass is fully open. When the booster compressor is fully unloaded and the unloading valve is fully open, the booster compressor is shut off and bypass flow for unloading reverses direction to permit flow from the condenser to the second stage past the shut off booster compressor.

Abstract: A thermally protected heater element is located in an oil sump such that it is normally located beneath the surface of the oil whereby the oil is heated and acts as a heat sink relative to the heater element. If the oil level drops below the heater element, the thermal protection disables the heater element and the compressor whereby the location of the heater element defines the nominal minimum oil level.

Abstract: The slide valve and the slide stop of a screw compressor are infinitely positionable over their range of movement. Movement is achieved by fluid pressure acting across an actuating piston in combination with the fluid pressure acting on the slide valve and slide stop plus a spring bias.

Abstract: There is disclosed a refrigeration system employing multi-stage compressors, several unique modes of operation thereof, a sub-cooler/economizer for sub-cooling the condensed refrigerant prior to vaporization in the evaporator, as well as an improved expansion valve arrangement for controlling second stage discharge temperature, another valve arrangement for controlling economizer liquid discharge temperature, an interstage intercooler for use in a hot water system, a satellite compressor arrangement for ultra-low temperature applications, and an improved liquid-suction heat exchange arrangement.

Abstract: An economizer is connected to a fluid line connecting the first and second stages of a compressor at a point downstream of the bypass for unloading the first stage. The economizer flow controls the discharge temperature of the second stage and, in addition, coacts with the bypassing of the first stage such that all of the flow supplied to the second stage is at system suction pressure when the bypass is fully open.

Abstract: Gaseous refrigerant is supplied from a flash tank economizer to cool the motor of a hermetic or semi-hermetic compressor when there is a sufficient flow available. When the flow becomes too small, liquid refrigerant is supplied to the shell of the compressor for cooling the motor.

Abstract: In a compressor of the type in which there is a movable trapped volume such as a screw or scroll type of compressor the trapped volume moves into and out of fluid contact with one or more valves. The valve(s) can provide fluid communication between the trapped volume and either suction for unloading or discharge for V.sub.i control.

Abstract: There is disclosed a refrigeration system employing multi-stage compressors, several unique modes of operation thereof, a sub-cooler/economizer for sub-cooling the condensed refrigerant prior to vaporization in the evaporator, as well as an improved expansion valve arrangement for controlling second stage discharge temperature, another valve arrangement for controlling economizer liquid discharge temperature, an interstage intercooler for use in a hot water system, a satellite compressor arrangement for ultra-low temperature applications, and an improved liquid-suction heat exchange arrangement.

Abstract: A refrigeration type plant comprises a rotary, positive displacement machine which as at least one rotor provided with spiral lobes and intervening grooves. The plant further comprises a condenser communicating with an outlet port (60) of the compressor through a high pressure channel (14), an evaporator communicating with an inlet port (58) of the compressor through a low pressure channel (18), a vessel for an intermediate pressure communicating with an intermediate port (38) of the compressor through an intermediate pressure channel (36), the intermediate port (38) being spaced from the inlet port (58) as well as from the outlet port (60), and a pressure reducer for decreasing the high pressure in the condenser to the intermediate pressure in the vessel and to the low pressure in the evaporator, respectively. A selectively adjustable valve (40) is provided for forming a communication between the intermediate channel (36) and the low pressure channel (18).

Abstract: A unique multi-stage refrigeration system for multiple product-display cases in which each display case has a low-stage booster compressor disposed therein. Each booster compressor compresses refrigerant received from the evaporator in its display case and feeds same to a bank of high-stage compressors disposed in a remotely located equipment room. A mechanical sub-cooler is provided for controlling liquid refrigerant temperature, and an improved lubrication system is provided for balancing the distribution of lubricant throughout the system. Several modifications of the system are also shown.

Abstract: A system for efficient power output regulation of internal combustion engines employs an engine intake air expansion/compression device coupled to the engine and driven thereby. The device has a variable volume chamber and a control for admitting and abruptly trapping desired volumes of atmospheric air within the chamber. The trapped volume of air is expanded to maximum value and then reduced after expansion until the engine intake displacement volume level is reached. At that point, the device exposes the trapped volume of air to the engine intake manifold. As the device is coupled to the engine, its maximum chamber volume per engine revolution remains essentially a fixed ratio of engine intake displacement per engine revolution.

Abstract: A refrigeration system characterized by a first stage booster compressor feeding multiple parallel connected second stage compressors in an otherwise conventional closed loop refrigeration system utilizing an economizer between the condenser and evaporator and returning economizer vapor to the inter-stage pressure point between the first stage and second stage compressors operates in a very flexible and highly efficient manner by driving the booster, first stage compressor at variable speed and the second stage compressor(s) at constant speed, at maximum capacity, with those machines incapable of being unloaded. The control system utilizing a sensor for sensing evaporator pressure, evaporator temperature or suction pressure, varies the speed of the drive motor for the first stage booster compressor to initially slow down the booster and secondly connect or disconnect the second stage compressor from the system. The booster is always operating and the economizer is always active in the system.

Abstract: A space conditioning closed loop refrigeration system, particularly a vehicle air conditioning system utilizing a positive displacement compressor having a slide valve for varying the capacity and shiftable between full load and full unload positions and vice versa and driven therebetween by a linear fluid motor having a movable member coupled to the slide valve and forming a first chamber which is normally dumped via a slide valve modulator to compressor suction pressure and a second chamber open to compressor discharge pressure. A restricted passage between chambers tends to cause the first chamber to reach compressor discharge pressure absent that chamber dumping to suction.