Abstract: A thermostatic valve such as a steam trap, incorporates a cup shaped trap repair cartridge having the lower end of an annular intermediate valve body of cast metal threaded into an upwardly open, internally threaded cup shaped valve casing. The trap repair cartridge in turn receives the external threads of an inverted cup shaped cover of cast metal whose lower annular wall has threads on its outer periphery matching the internal threads of the annular intermediate valve body. The trap repair cartridge includes a conical bottom wall terminating in a flat, central horizontal bottom wall portion which is provided with an axial hole defining a valve seat. A hollow sheet metal thermostatic actuator is provided with an axial projection on one surface which projection is threaded about its outer periphery and which projection is threaded into a mating tapped hole within the bottom of an adaptor post.

Abstract: A back-stopping device rotor assembly is coupled to a motor shaft to rotate therewith and include a pair of L-shaped flyweights pivotably mounted to a channel crossbar, on respective sides of a motor shaft, which crossbar rotates at right angles to the shaft axis. The flyweights are pivotably mounted to the crossbar at points closer to their end facing the motor housing at positions regularly spaced from the shaft while extending parallel to the shaft, with the motor rotor at rest. A bracket mounted on the motor housing to one side of the shaft supports a stop relative to the shaft borne device rotor such that when the motor rotates at high acceleration in a first forward direction, the flyweights pivot during initial rotation to positions such that their ends proximate to the stops sweep through a stop recess and do not impact the stop. Low acceleration, backward rotation of the motor shaft up to a maximum of 180.degree.

Abstract: A pair of positive displacement pumps are connected in series between a liquid fuel supply tank and a burner nozzle. Mechanically linked, identical variable orifices are interposed within the supply line between the pumps and the nozzle. A first pressure regulator is connected across the supply line between the pumps and a return line leading from the nozzle back to the supply tank. A pressure sensing line for the first pressure regulator is connected to the supply line on the discharge side of the second positive displacement pump to regulate the outlet pressure of the first pump. The discharge line for one of the variable orifices leads to the burner nozzle and forms part of the supply line, while the discharge line for the other variable orifice bears a second pressure regulator and connects to the return line.

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.

Abstract: A vertical axis hermetic compressor includes an inner cylindrical housing fixed internally of a sealed outer enclosure bearing paired helical screw rotors defining with the inner housing closed thread compressor compression chambers. An electrical drive motor overlies the rotors and is shaft connected to one of the rotors. Compressed refrigerant vapor, where refrigerant is the working fluid, discharges through the motor rotor. A deflector within the top of the outer enclosure such that oil impacted by gas flow discharging axially from the motor adheres to the deflector to provide oil separation.

Abstract: The shaft coupling a reciprocating piston of a fluid motor to a slide valve shiftable longitudinally along a screw compressor housing and varying the amount of compressor suction gas returned to the suction port for varying compressor capacity constitutes an outer hollow tube having a smaller diameter indicator shaft mounted axially therein. The shaft carriers a helical V-groove on its exterior surface and a spring biased pin projecting radially inwardly from the outer tube rides in the helical groove such that, as the slide valve reciprocates, driven by the fluid motor piston, the indicator shaft is rotatably driven about its axis. Multiple cams fixed to the indicator shaft and rotatable therewith actuate juxtapositioned microswitches to indicate full load position, full unload position, and two intermediate load positions for the slide valve. The indicator shaft is directly axially connected to a potentiometer to provide an electrical analog output signal.

Abstract: Helical screw rotors for a screw rotor machine having improved asymmetric screw profiles on both male and female rotors, wherein the male rotor lobe leading flank comprises solely first and second circular arcs with the first circular arc subscribed by a first radius which lies on a radial line through the male rotor center at an offset angle to the male rotor lobe center line in the direction of the trailing flank of the rotor lobe to create a male rotor tip point inherently including a male rotor lobe sealing strip.

Abstract: A modular three block assembly provides unloading control for a hydraulic cylinder functioning to variably position a slide valve on a helical screw rotary compressor. A first compressor block is fixedly and sealably mounted within the hermetic compressor outer casing and has through holes leading to a first tube connected to a source of oil under discharge pressure forming the hydraulic fluid for the hydraulic cylinder, a second tube connected to the hydraulic cylinder and a third tube to the suction tube returning low pressure vapor to the compressor suction side. A needle valve block is fixedly mounted to the external face of the compressor block and bears within longitudinal through passages paired needle valves determining the load and unload flow rates for the hydraulic fluid passing through said compressor block through holes.

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: A vertical axis hermetic compressor includes an inner cylindrical housing fixed internally of a sealed outer enclosure bearing paired helical screw rotors defining with the inner housing closed thread compressor compression chambers. An electrical drive motor overlies the rotors and is shaft connected to one of the rotors. Compressed refrigerant vapor, where refrigerant is the working fluid, discharges through the motor rotor. Centrifugal force functions as a primary oil separator for oil entrained within the working fluid. An inverted dish deflector underlies a gas discharge port axially within the top of the outer enclosure such that oil impacted by gas flow discharging axially from the motor adheres to the deflector to provide secondary oil separation while the gas passes about the periphery of the deflector to escape through the discharge opening of the outer enclosure.

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: A tubular cylinder block is mounted for rotation about its axis within a cylindrical bore of a pump housing. The pump housing has circumferentially spaced inlet and outlet ports opening radially to the bore. Right angle intersecting diametric passages extend through the cylinder block and are alignable with the inlet and outlet ports during rotation of the drive block, the diametric passages being square in cross-section, and piston members of corresponding square transverse cross-section are slidably positioned within respective diametric passages with the piston members bearing square slots within side faces thereof intermediate of their ends facing axially. A square drive block is carried commonly within the piston member slot whose axis of rotation is adjusted eccentrically relative to the axis of rotation of the cylinder block. Cylinder block internal peripheral grooves separated by lands control fluid passage via the piston formed cavities between the inlet and outlet ports.

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: Parallel connected compressors are provided with an oil management scheme in which an oil equalization port on one compressor is connected via an oil return solenoid operated valve within a small diameter line to an injection port of a second compressor, and vice versa. When the oil level in one compressor drops to a level sensed by an oil float switch, the oil float switch changes state, the oil return solenoid operated valve is opened, feeding its injection port and energizing a one minute on delay timer. Failure of the oil float switch to reset itself causes the compressor to go off on oil failure, and the oil return solenoid operated valve is closed. If the oil float switch resets itself at any time during the first minute, upon resetting, an off delay timer is energized to keep the oil return solenoid operated valve open for an additional minute, and the compressor continues to operate.

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.