Abstract: Where a helical screw compressor gas or vapor working fluid is not too soluble in the compressor lubricant for compression process cooling, such lubricant after separation from the working fluid and cooled to as a low a temperature as possible and operating at as high a pressure as possible, is fed to an atomizing nozzle and injected into the inlet end of the compressor. This produces a cloud type blanket of cool atomized droplets uniformly dispersed within the suction vapor or gas allowing the highest possible rate of heat transfer to occur during the compression process and achieving the highest possible isothermal efficiency in a gas compression system or operation near vapor saturation values in a refrigeration vapor compression system while avoiding large hydraulic losses in the compressor. Working fluids such as helium, air, and ammonia may provide extremely high superheated gas or vapor at the compressor inlet.

Abstract: An air conditioning control system, for use with an air conditioning system having a variable-capacity compressor, varies the compressor loading in accordance with evaporator pressure at return air temperatures above an upper set point and fixes the compressor loading at 33% thereabouts when the return air temperature falls below the upper set point. If the temperature continues to fall, the compressor will be shut down at a lower set point at which the heating apparatus may be automatically and momentarily activated. The compressor will not again be activated until the temperature rises above the upper set point. The heating is deactivated as soon as the temperature rises above the lower set point.

Abstract: A helical screw rotary compressor for a closed loop refrigeration system such as an air conditioning system for a bus or like vehicle is connected in series with a condenser and an evaporator, in that order, with the evaporator at a raised position relative to the compressor and utilizes a vaporizable refrigerant which is miscible with a lubricating oil employed to lubricate the moving components of the screw compressor. The bus engine driven, clutch operated, helical screw rotors are mounted within parallel intersecting bores within the compressor housing. A slide valve underlies the intermeshed rotors and forms a portion of the screw compressor envelope, the rotors opening to a suction port connected to the outlet side of the evaporator above the rotors. A high pressure discharge port at one end of the intermeshed rotors leads to an auxiliary chamber bearing an unload cylinder which drives the slide valve and which opens at the top to a housing discharge port leading to the condenser.

Abstract: Intermeshed helical screw rotors are mounted for rotation by anti-friction bearings surrounding integral shafts extending axially outward of the ends of the intermeshed screw rotors and within respective high pressure outlet and low pressure inlet bearing housings, sealed to the exterior. Oil from a separator/sump at or near compressor discharge pressure feeds via a closed passage to annular cavities surrounding the rotor shafts upstream of the outlet housing bearings. Oil seeps through very narrow annular gaps functioning as self-cleaning upstream capillaries to the outlet bearing cavities with the pressure reduction causing oil mist lubrication of the confined bearings within the outlet bearing housing. Further passages fluid connect the outlet bearing housing cavities to similar cavities within the inlet bearing housing where mist lubrication of the inlet bearings occurs.

Abstract: An electronic control system for sequential actuation of a four-way solenoid valve is used to selectively load and unload a slide valve control for a screw compressor. The electronic control system can be responsive to output or refrigerant pressure or evaporator pressure or inlet pressure and pulses a four-way solenoid valve to selectively load and unload the compressor so that it will maintain system pressure within a preselected deadband. Selective pulsing of the four-way solenoid valve is used to gate hydraulic fluid to load and unload chambers separated by a piston coupled to a slide valve which shifts longitudinally and changes the capacity of the screw compressor. The control system senses system pressure (reflecting load), and when a limit pressure is reached, a gas bypass solenoid valve (or dump valve) and fast-unload system is actuated to entirely unload the compressor. The control circuit also monitors current to the motor which drives the screw compressor.

Abstract: A stepping piston is projected into the path of a slide valve drive piston to limit piston movement and thus the slide valve towards maximum unload position determined by piston bottoming out against the cylinder wall. The slide valve main drive piston stroke is also correlated to desired slide valve positions along the intermeshed helical screw rotors of the helical screw rotary compressor to provide, for example, stepped unloading at compressor full load, two-thirds full load, and one-third full load.

Abstract: A rotary helical screw compressor for a refrigeration system employing a condensable refrigerant comprises intermeshed rotors mounted for rotation by way of anti-friction bearings, within a hermetic housing. A lubricating oil miscible in liquid refrigerant is supplied to the compressor in a mass ratio of between 0.25 and 12%, by weight of solution. Vaporized working fluid at discharge pressure and bearing oil mist is permitted to seep through the anti-friction bearings in closed loops, from the discharge side of the machine towards the suction side, for effective lubrication. Thus, the refrigeration system is oil pump free, oil sump free, and oil filter free. Liquid refrigerant oil solution may be bled from the condenser and injected into the compression chamber defined partially by the intermeshed rotors at a point in the compression process where the compression chamber is cut off from suction and discharge sides of the compressor, for cooling the rotors.

Abstract: A vehicle engine driven helical screw compressor for a gas refrigeration system includes a slide valve actuator for shifting the compressor slide valve to load and unload the compressor. In addition to a first solenoid operated control valve selectively connecting the slide valve actuator to compressor high side pressure to effect loading of the compressor and a second solenoid operated control for connecting the slide valve actuator to the compressor low side pressure to effect unloading, a tracking valve responsive to engine acceleration and deceleration connects the slide valve actuator to the low side pressure during engine acceleration for immediate unloading of the compressor and connects the slide valve actuator to the high side pressure during engine deceleration to immediately load the compressor.

Abstract: A check valve within a closed loop refrigeration system isolates the evaporator from the helical screw compressor. A normally open, solenoid operated valve is positioned within an unload line having one end coupled to a drive cylinder outboard chamber to the side of the piston opposite an inboard chamber which opens to compressor discharge pressure. The other end of the unload line is connected to the system low pressure side, downstream of the check valve. The same drive cylinder outboard chamber opens via a load line to the system high pressure side through a normally closed solenoid operated valve. Upon compressor shut down, the outboard chamber is vented to the system low pressure side, while the opposite side of the unloader drive cylinder piston sees the compressor high side, thus driving the slide valve to full unload position and eliminating the coil spring normally needed to drive the slide valve to that position.

Abstract: Scavenging is applied to a conventional refrigeration cycle to return most of the energy normally remaining in a warm condensed liquid to the cycle. This permits considerably more energy to be picked up in the evaporator of the cycle than under conventional practice. The concept is applicable to any type positive displacement compressor where an intake of evaporator generated gas can be trapped in the compressor, with the scavenged gas then added prior to mechanical compression. The concept is particularly applicable to reciprocating compressor type heat pump systems.

Abstract: An air source heat pump system incorporating a refrigerant charged bulb within the air flow passing over the outdoor coil of the heat pump system to sense outside ambient air temperature. The refrigerant charged bulb supplies a variable saturated pressure which acts upon a bellows of a control unit whose opposite side is subjected via a second bellows to saturated suction pressure (corresponding to refrigerant evaporating temperature) of the refrigerant returning from the outdoor coil to the inlet of the compressor. The bellows provides a spring load. An electrical switching device responsive to this pressure differential acts to first block unnecessary loading of the compressor and secondly to initiate unloading of the compressor. Additional switching means prevents excessive unloading of the compressor and insures subsequent initiation of loading to prevent liquid logging of the evaporator coil.

Abstract: An electronic control system for sequential actuation of a four-way solenoid valve is used to selectively load and unload a slide valve control for a screw compressor. The electronic control system is responsive to output air pressure and pulses a four-way solenoid valve to selectively load and unload the system so that it will maintain system pressure within a preselected deadband. Selective pulsing of the four-way solenoid valve is used to gate hydraulic fluid to load and unload chambers separated by a piston coupled to a slide valve which shifts longitudinally and changes the capacity of the screw compressor. The control system senses output line pressure, and when a limit pressure is exceeded, a dump solenoid valve and fast-unload system is actuated to entirely unload the system of air pressure until reduced to a level below the set deadband. The control circuit also monitors current to the motor which drives the screw compressor.

Abstract: A multi-cylinder reciprocating compressor is automatically staged at low ambient temperature to improve refrigerant volume flow while facilitating subcooler operation and return of vaporized refrigerant from the subcooler to the inlet of the second stage cylinders of the compressor in the two stage mode. A solar evaporator substitutes for the outdoor coil when the solar heated storage tank temperature exceeds that of ambient. During staging mode, the wrist pins of the low side cylinders and the high side cylinder undergo proper load reversals, since intermediate suction pressure is applied to the wrist pin of the high side cylinders.

Abstract: A solar-assisted multiple source and multiple sink heat pump system for use in residential homes includes a solar/air coil mounted in the attic of the residential home and selectively open to the attic interior with the attic roof bearing a solar window with selective shield permitting the attic solar space to constitute a passive solar collector. The solar/air coil is positioned within duct work which selectively opens to the attic interior or the outside air to permit thermal energy pick up from the attic solar space or outside air or wasting of heat thereto. The inside air coil is also mounted in a separate duct work within the attic shielded from the attic interior but selectively open thereto and to and from the building interior beneath the attic for adding heat to the building interior or removing the same. One or more thermal storage tanks may constitute heat and cold sinks.

Abstract: A helical screw rotary compressor or expander rotatably mounts intermeshed helical screw rotors within intersecting bores of a casing. An axially extending recess provided within the barrel portion of the casing in open communication with the bore bears a slide valve member whose inner face is complementary to the envelope of the casing. The slide valve member controls communication between the working chamber defined by the rotors and the casing to the outlet port and bears means at the end in communication with the outlet port for sensing the closed thread pressure adjacent to the end of the slide valve member closing off the outlet port. Comparison of that closed thread pressure to the outlet port pressure permits controlled shifting of the slide valve member to prevent overcompression and undercompression, when the unit acts as a compressor, or underexpansion or overexpansion when the unit acts as an expander.

Abstract: A compact, helical screw compressor/expander unit mounted in a vehicle and connected to the vehicle engine driven drive shaft has inlet and outlet ports and a capacity control slide valve and a pressure matching or volume ratio slide valve, respectively, for said ports. A refrigerant loop includes the compressor, a condenser mounted in the path of air flow over the engine and an evaporator mounted in a fresh air/cab return air flow duct for the occupant. Heat pipes thermally connect the cab air flow duct to the engine exhaust system which also bears the vapor boiler. Selectively operated damper valves control the fresh air/cab return air for passage selectively over the evaporator coil and the heat pipes as well as the exhaust gas flow over opposite ends of the heat pipes and the vapor boiler.

Abstract: A compression module in the form of a four cylinder reciprocating piston compressor, having two cylinders for each of two cylinder heads, is interconnected by conduits and manifolds which in turn incorporate solenoid operated control valves and check valves to provide five pressure levels for the compressor cylinders to remove automatically intermediate pressure refrigerant and to return intermediate pressure refrigerant, to achieve single or multiple cylinder compressor staging, and effect unloading of one head by cutting off low pressure suction return to that compressor head.

Abstract: A closed loop refrigeration system such as an air source heat pump includes a hermetic screw compressor and a helical screw rotary expander connected to an electric induction drive motor. The closed loop refrigeration circuit permits an air source evaporator to constitute a heat source for supplying vaporized refrigerant to the compressor and expander, while both are mechanically coupled to the electric induction drive motor and with both driven as compression units. The air source evaporator feeds to slide valve controlled inlet ports of both the compressor and expander. Compressed vapor from both units passes to condenser coil(s) such as heating condensers to increase the system capacity under this mode.

Abstract: In a vertical hermetic compressor, an inner cylindrical housing coaxially mounted within a sealed outer enclosure, sealably carries at its lower end, paired helical screw rotors defining with the inner housing a screw compressor compression chamber and supports coaxially with one of the screw rotors and constituting an axial extension thereof the compressor electrical drive motor by longitudinally spaced tapered roller bearings. Oil is bled from the sump and fed to the suction inlet tube to the compressor upstream of the working gas filter. Compressed working fluid is discharged axially downwardly with the lower tapered roller bearing assembly providing a minimal high pressure gap between the screw rotor ends and the stationary end plates. Entrained oil from the discharge passage which extends through the electric motor rotor seeks the suction side of the compressor through the upper of the two tapered roller bearing pack assemblies for controlled continuous lubrication of the upper bearing assembly.

Abstract: A helical screw rotary compressor or expander rotatably mounts intermeshed helical screw rotors within intersecting bores of a casing. An axially extending recess provided within the barrel portion of the casing in open communication with the bore bears a slide valve member whose inner face is complementary to the envelope of the casing. The slide valve member controls communication between the working chamber defined by the rotors and the casing to the outlet port and bears means at the end in communication with the outlet port for sensing the closed thread pressure adjacent to the end of the slide valve member closing off the outlet port. Comparison of that closed thread pressure to the outlet port pressure permits controlled shifting of the slide valve member to prevent overcompression and undercompression, when the unit acts as a compressor, or underexpansion or overexpansion when the unit acts as an expander.