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: A refrigeration system utilizes a small high speed centrifugal compressor driven by a directly coupled, high frequency, electric motor. The motor has a double-ended shaft which supports the rotors of low pressure and high pressure centrifugal compressor stages. The motor operates in the refrigerant atmosphere so as to eliminate the requirement for rotating shaft seals. High frequency power (3750 Hz) is supplied to the motor, which runs at 75,000 RPM. The system utilizes a novel flash intercooler between the compressor stages.

Abstract: The rotary positive displacement compressor has an intermediate port (42) for fluid from an intermediate pressure channel (30) and has a bleed port (44) for recirculation of partly compressed fluid through a return channel (32). It is suggested to provide the compressor with valve means (36), selectively adjustable between two end positions. In a first end position it opens up a direct communication between these channels (30, 32) and opens the bleed port (44), whereby fluid flows directly from the intermediate pressure channel (30) to the return channel (32) simultaneously as fluid within the working space of the compressor flows to the return channel (32) through the intermediate port (42) as well as through the bleed port (44). In a second end position the bleed port (44) is closed and said direct communication is blocked. The disclosure also relates to a refrigeration plant comprising such a compressor.

Abstract: Heat pump systems (principally FIG. 3; also FIGS. 5, 7 or 9) comprising, in circuit of fluid, an injected compressor 113, communicating a compressed gas discharge 137 to a condenser 100, communicating an at least partly liquid output 130 to an expansion valve 101, communicating therefrom 131 to a separator 110, communicating liquid therefrom 134 to a capillary tube 111, and communicating gas therefrom 132 to a control valve 112 that is responsive to ambient temperature; 111 communicating the liquid therefrom 135 to an evaporator 102, communicating gas therefrom 136 to an inlet of the injected compressor 113; the control valve 112 communicating gas therefrom 133 to an injection input of the injected compressor 113; and the expansive valve 101 being adjustable 176,171 responsive to the temperature of the gas communicating 136 from the evaporator 102 to the injected compressor 113. Where the fluid comprises a non-azeotropic refrigerant blend (NARB), the system (FIG. 5; also FIG.

Abstract: A refrigerator apparatus is provided having a cabinet with a freezer compartment and a fresh food compartment. A refrigeration system is included having a first expansion valve, a first evaporator situated in the freezer compartment, a first and second compressor, a condenser, a second expansion valve, and a second evaporator situated in the fresh food compartment all connected together in that order and in series in a refrigerant flow relationship. First and second fans are provided in the freezer and fresh food compartments, respectively. A servovalve is connected between the first evaporator and the first compressor for reducing refrigerant flow through the first evaporator when activated. A first thermostatic controller situated in the freezer compartment causes operation of the compressors and fans when a selected temperature in the freezer is exceeded. A second thermostatic controller situated in the fresh food compartment causes operation of the servovalve when a predetermined value is reached.

Abstract: A rotary compressor includes first and second compressor sections, and a motor for driving the compressor sections. The first and second compressor sections have first and second cylinders, respectively, and each cylinders has a suction port. First and second suction pipes are connected to the suction ports, and first and second change over valves are provided at the first and second pipes, respectively. The first cylinder has a release port for releasing a port of the gas being compressed in the first cylinder. A release pipe provided with a third changed over valve is connected to the release port. The operaations of the first to third valves are controlled by a control circuit so that the capacity of the compressor varies in the plurality of steps in accordance with the loads applied thereto.

Abstract: A refrigerating circuit apparatus includes a two stage compressor having an upper stage compressing cylinder and a lower stage compressing cylinder, a heat stage tank, an upper stage side variable opening expansion valve and a lower stage side variable opening expansion valve. The upper stage side variable opening expansion valve is controlled toward its closed position for executing a heat storing operation wherein heat is discharged from refrigerant to the heat storage tank. The upper stage side variable opening expansion valve is opened and the lower stage side variable opening expansion valve is closed for carrying out a defrosting operation. Heat stored in the heat storage tank is used in the defrosting operation for removing frost accumulated on an external heat-exchanger during the heating operation.

Abstract: A refrigeration and heat pump system of the refrigerant gas compression type having selectively operable first and second heat exchangers, respectively, in heat exchange relationship with a heat sink or source and a heating or cooling load, and with a an internal combustion engine driving a plurality of refrigerant gas compressors with more than one of the compressors selectively engagable when the system is operated in the heat pumping mode and the heat source is at low ambient temperature. The system includes at least one speed increaser connected between the plurality or compressors, so that the compressors operate at difference speeds although driven by the same engine.

Abstract: Disclosed is a cold-air generating device which comprises a first refrigerating system 15 including a first evaporator 1 and a compressor 4 and adapted to cool air to such a degree that the water contained therein will not become frozen, and a second refrigerating system 26 including a second evaporator 2 and a compressor 16 and adapted to further refrigerate the air dehumidified and cooled while passing through the first evaporator 1 down to a temperature below freezing point. Air inlets 27 and 28 may be provided in the upper sections of the first and second evaporators 1 and 2, respectively, so that a downward airflow will be generated therein, the respective lower sections of the first and second evaporators 1 and 2 being connected to each other through a drain pan 3. Furthermore, gauze 29 may be provided on that side of the second evaporator 2 which is connected to the first evaporator 1.

Abstract: A refrigerating circuit apparatus includes a two stage compressor having an upper stage compressing cylinder and a lower stage compressing cylinder, a heat storage tank, an upper stage side variable opening expansion valve and a lower stage side variable opening expansion valve. The upper stage side variable opening expansion valve is controlled toward its closed position for executing a heat storing operation wherein heat is discharged from refrigerant to the heat storage tank. The upper stage side variable opening expansion valve is opened and the lower stage side variable opening expansion valve is closed for carrying out a defrosting operation. Heat stored in the heat storage tank is used in the defrosting operation for removing frost accumulated on an external heat-exchanger during the heating operation.

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: The refrigeration system disclosed herein operates evaporators in both moderate and low temperature environments, respective compressors being associated with each type of evaporator. A condenser is provided for rejecting heat into the environment. Refrigerant from the condenser is provided both to the moderate temperature evaporators and to a refrigerant processing vessel which can allow a mixture of gas and liquid phase refrigerant to separate. A heat exchanging conduit is submerged in the liquid phase refrigerant in the lower portion of the processing vessel and the outlets of the compressors serving the low temperature evaporators are connected to the inlet end of that conduit. Liquid phase refrigerant from the processing vessel is provided to the low temperature evaporators.

Abstract: An air conditioning system with a refrigerator integrated, includes (a) an air conditioning device having a first cycle comprising (i) a compressor for compressing a refrigerant to turn it into the gaseous refrigerant having high temperature and high pressure, (ii) a condenser for cooling the gaseous refrigerant to turn it into the liquid refrigerant having middle temperature and high pressure, (iii) a first expansion valve for giving adiabatic expansion to the liquid refrigerant to turn it into the vaporous liquid refrigerant having low temperature and low pressure, and (iv) a first evaporator for evaporating the vaporous liquid refrigerant to turn it into the gaseous refrigerant, and for returning the gaseous refrigerant to the compressor, and (b) the refrigerator having a second cycle comprising (i) the compressor, (ii) the condenser, (iii) a second expansion valve for giving adiabatic expansion to the liquid refrigerant received from the condenser thereby to turn it into the vaporous liquid refrigerant ha

Abstract: A refrigeration system suitable for use in a household refrigerator having a freezer compartment and a fresh food compartment is provided. The refrigeration system includes a first capillary tube, a first evaporator for providing cooling to the freezer compartment, a two stage compressor, a condenser, a second capillary, and a second evaporator providing cooling to the fresh food compartment. All the above elements are connected together in series in that order, in a refrigerant flow relationship. A phase separator connects the second evaporator to the first capillary tube in a refrigerator flow relationship and the phase separator provides intercooling between the first and second compressors.

Abstract: A refrigerator system suitable for use in a household refrigerator having a freezer compartment and a fresh food compartment is provided. The refrigerator system includes a first expansion valve, a first evaporator for providing cooling to the freezer compartment, a first compressor, a second compressor, a condensor, a second expansion valve, and a second evaporator providing cooling to the fresh food compartment. All the above elements are connected together in series in that order, in a refrigerant flow relationship. A phase separator connects the second evaporator to the first expansion in a refrigerator flow relationship and the phase separator provides intercooling between the first and second compressors.

Abstract: A system of parallel compressors for compressing fluids miscible with oil. Means are provided for internally separating each compressor connected in parallel into a discharge chamber, a suction chamber, and a crankcase chamber, the chambers of each compressor being independent of one another. The crankcase chambers are connected in oil and gas flow communication with one another. A suction manifold is connected to the suction chambers, and each crankcase chamber is equalized with suction pressure. A discharge manifold is connected to the discharge chambers. Means for separating the oil from compressed fluids leaving the discharge chambers and returning the oil so separated to the crankcase chambers are also provided.

Abstract: An auxiliary power system for a truck or other heavy duty vehicle. A secondary engine which is smaller than the vehicle's main engine is used to generate heat and electrical power, and to drive an auxiliary air conditioning system The coolant systems of the two engines are interconnected so that when the main engine is off and the secondary engine is on, waste heat from the secondary engine is transferred by coolant flowing through the water jacket of the secondary engine to the main engine and also to heater cores in the truck's cab and sleeper. An electrical generator driven by the secondary engine provides electrical energy. The auxiliary air conditioning system includes an auxiliary compressor and an auxiliary condenser, and connections for efficiently interconnecting the auxiliary air conditioning system with the truck's primary air conditioning system.

Abstract: A refrigeration system comprises a plurality of evaporators and a plurality of conduits for feeding cooling-medium vapor evaporated in the evaporators to a plurality of compressors having a common outlet header for compression therein. Conduits extends between the common outlet header of the compressors and the inlets of the evaporators to feed the heated cooling-medium vapor produced by the compressors to one, several or all of the evaporators for defrosting the same.

Abstract: In the supermarket cooling system disclosed herein, a variety of evaporative loads having different suction requirements are served by respective compressors, each operating across a corresponding pressure differential but pumping into a common high side header. A single condenser unit serves the combined refrigerant flow from all loads and, from the condenser, the refrigerant flow normally passes through an air-cooled heat reclaim exchanger which is downstream of an air conditioning evaporator in the air conditioning ductwork. The heat reclaim exchanger can be selectively bypassed for certain extreme conditions of operation. By varying the air flows through the condenser unit and the heat reclaim exchanger, a highly efficient thermal operation under the most prevalent conditions is achieved in a very simple hardware configuration.

Abstract: A process and apparatus for a multistage heat pump system. The system includes a compressor which compreses a working medium, a condenser which condenses the working medium, and an evaporator which evaporates the working medium, and has a construction in which at least either one of the condenser or the evaporator includes a plurality of heat exchange chambers, at least either one of the delivery side or the suction side of the compressor including a plurality of ports that are on different pressure levels, the plurality of heat exchange chambers and the plurality of ports being connected to each other. A cascade system is also disclosed, in which two working mediums are used, one for a high-temperature cycle and one for a low-temperature cycle. The cascade heat exchanger can be single or multistage. The above construction allows the temperature of the working medium to vary along with the temperature variations of a heat source fluid.

Abstract: An auxiliary power system for a truck or other heavy duty vehicle. A secondary engine which is smaller than the vehicle's main engine is used to generate heat and electrical power, and to drive an auxiliary air conditioning system. The coolant systems of the two engines are interconnected so that when the main engine is off and the secondary engine is on, waste heat from the secondary engine is transferred by coolant flowing through the water jacket of the secondary engine to the main engine and also to heater cores in the truck's cab and sleeper. An electrical generator driven by the secondary engine provides electrical energy. The auxiliary air conditioning system includes an auxiliary compressor and an auxiliary condenser, and connections for efficiently interconnecting the auxiliary air conditioning system with the truck's primary air conditioning system.

Abstract: A refrigeration system has multiple compressors in a parallel arrangement. The pressures in the shells of operating compressors are maintained equal by the controlled delivery of suction gas and entrained oil to the shells of individual operating compressors in quantities which maintain the pressures therein equal. A valve, directly responsive to compressor shell pressures, occludes the flow of suction gas to the shell of an operating compressor in which the pressure is greater than that found in the shell of another operating compressor so as to equalize the pressures in the compressor shells. The equalizing valve arrangement directs and apportions essentially the entire amount of suction gas to the shells of operating compressors while cutting off the flow of suction gas into the shells of non-operating compressors.

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 refrigerating cycle apparatus of an improved operating efficiency, which is constructed, in combination, with: a refrigerant circuit including an evaporator, a compressor, a condenser, a first throttle, an economizer for separating the refrigerant into a gas phase and a liquid phase, and a second throttle, all these component elements being interconnected in the order as mentioned; and a piping for the economizer, which connects the gas phase portion of the economizer and an intermediate pressure region of the compressor, wherein the length of the economizer is set in such a value that is greater than the values to be determined from a Mollier's diagram on the basis of the operating conditions for the refrigerating cycle apparatus for the increase in the cooling or warming capability as well as the increase in the coefficient of performance.

Abstract: A refrigerant apparatus having a compressor, a condenser, a first expansion valve means, a gas-liquid separator, a second expansion valve means and an evaporator. The compressor has a plurality of cylinders one of which is connected with the gas phase of the gas-liquid separator in order to inject the gas coolant into the compressor, other cylinders of the compressor being connected to the evaporator in order to suck the coolant from the evaporator. Since the gas coolant within the gas-liquid separator is injected into the compressor, the cooling capacity of the coolant passing through the evaporator can be expanded so that the cooling capacity of the present invention is increased. Though the gas coolant within the gas-liquid separator which includes no lubricant is sucked toward the compressor, the compressor can be lubricated by the lubricant coolant effectively, because the same compressor sucks the coolant containing lubricant from the evaporator.

Abstract: Improvements in heat pump systems having indoor and outdoor heat exchangers, at least two compressors, and conduit connections including associated compressor selector and change over valves operable to control the direction of flow of fluid medium through the heat exchangers from the compressors, and to control whether one or more of the compressors will be operating the system and in all cases to connect the operating compressor or compressors in series with the heat exchangers.

Abstract: The stream of suction gas and entrained oil flowing from the evaporator in a parallel compressor refrigeration system is directed into a flow separator where it diverges and is expanded into a separation chamber of increased cross-sectional area. A takeoff conduit has an inlet end disposed generally in the center of the separation chamber which faces into the suction gas flow stream. Because of the location and size of the cross-sectional area of the inlet end of the takeoff conduit, a larger portion of the suction gas flow stream and oil entrained therein bypasses the takeoff conduit inlet than enters it. The separation chamber is in flow communication, at its outlet end, with the shell of the one of the compressors which is designated to receive a majority of the suction gas and oil entrained therein. The takeoff conduit is in flow communication with the other of the compressors.

Abstract: A method of enhancing the defrost and heating cycles of a transport refrigeration system for a straight truck, which refrigeration system includes a single refrigeration circuit selectively connectible to a compressor driven by the truck engine, or to a stand-by compressor driven by a motor connected to a stand-by source of electrical potential. The enhancement is achieved by slowly but continuously storing heat in an accumulator from the truck electrical system, or from the stand-by source of electrical potential, such that liquified refrigerant introduced into the accumulator during a defrost or heating cycle is immmediately vaporized. The slow but continuous rate of heat storage accumulates the requisite heat without unduly loading the truck electrical system or the truck engine.

Abstract: A hybrid heat pump wherein the operating medium is a mixture of media which dissolve in each other and have different boiling points. The condensation and/or the evaporation is performed on more than one pressure levels and at variable temperatures. The compressor performs the suction on more than one pressure levels and performs the discharge on more than one pressure level. Between low pressure operating medium (p.sub.1, p.sub.2) and large pressure operating medium (p.sub.3, p.sub.4, p.sub.5) the heat transfer is performed by the internal heat exchangers.

Abstract: A flow control valve in a unitary casing has a seat for a manual stem valve on one side of the valve opening and a seat for a check valve on the other side, the check valve being lightly urged toward closing position against differential pressure in the flow stream and being receptive to external pressure control.

Abstract: The refrigerating cycle apparatus of the invention is provided with a pair of condenser and evaporator, two compressors, and a riser piping for rising therethrough a refrigerant and provided at a suction pipe for one compressor, the suction pipe for the other compressor being connected with the riser piping, so that even when the flood back condition occurs during the individual operation of the one compressor, both compressors are adapted to maintain a proper oil quantity therein.

Abstract: A refrigeration system, and a method for operating the system, having a two-stage compressor for supplying refrigerant to a cooling coil, and having a desuperheater unit disposed between the two compressor stages. This desuperheater unit includes a container having heat exchange fluid therein and a coil, disposed in the heat exchange fluid, through which the refrigerant passes. During normal operation of the refrigeration system, both compressors are running. The desuperheater unit between the two compressor stages reduces the temperature of the compressed refrigerant before it reaches the second stage. The temperature of the heat exchange fluid is correspondingly increased in the course of the heat exchange. Also during normal operation, frost accumulates on the cooling coil, which is removed by a control device initiating a defrost cycle. When the defrost cycle begins, the first stage compressor is turned off while the second stage compressor continues to run.

Abstract: A discharge valve and baffle assembly is provided in a refrigeration system having either one or more compressors. The discharge valve and baffle assembly eliminates the effects of an established head upon starting the associated compressor, thereby permitting the compressor to quickly come up to speed for the established head. During compressor operation, the discharge valve and baffle assembly provides a suction force for holding the valve in the open position to prevent bouncing of the valve during part-load conditions and cycling of the valve between the open and closed positions during surge conditions. The assembly prevents backflow of refrigerant through the nonoperating compressor, and also provides a baffle effect to direct the flow of high pressure gaseous refrigerant uniformly into the condenser.

Abstract: A control system for controlling the capacity of a lead compressor of a refrigeration system having a lead and lag compressor when the lag compressor is in surge. A microcomputer system receives electrical input signals indicative of the lead and lag motor currents and closes the inlet guide vanes of the lead compressor when the lag compressor percent motor amps are below the lead compressor motor amps by more than a selected percentage for a specified period of time.

Abstract: Apparatus and method for controlling compressor operation in conjunction with sensing the lowest temperature operating evaporator coil, or area serviced thereby, of a commonly-piped cooling system. A thermoelectric sensor voltage output is compared with a set-point voltage by an integrator, the output of which is applied to control the pressure for the system.

Abstract: An air-conditioning and refrigerating system has a single vane-type rotary compressor, a single condenser, an air-conditioning evaporator and a refrigerating evaporator parallel to the air-conditioning evaporator. The compressor has main and auxiliary suction ports connected through air conditioning and refrigerating refrigerant return passages to the air-conditioning evaporator and to the refrigerating evaporator, respectively. The compressor is constructed such that the refrigerating refrigerant returned through the auxiliary suction port into a working chamber is mixed in the working chamber with the air-conditioning refrigerant returned through the main suction port into the working chamber before the refrigerating refrigerant is compressed in the working chamber.

Abstract: A flow-through surge receiver for a refrigeration system having compressor, condenser and evaporator means, in which a surge-type receiver forms a reservoir for liquid refrigerant and has a flow-through conduit receiving refrigerant from the condenser means and an outlet for passing such refrigerant directly to the evaporator means in by-pass relation with the receiver reservoir, and a passageway for establishing fluid communication between said conduit and reservoir below the normal liquid refrigerant level in the reservoir.

Abstract: A controlled refrigeration system includes a plurality of refrigerant compressors fed from a common suction manifold (line). Each compressor is associated with a respective controller. The individual controllers are set to effect the cutting in of its associated compressor at different levels of input voltage from a pressure transducer using digital techniques. The individual controllers each produce respective digital cut-in, cut-out, down-time delay and power-up delay signals. Respective logic circuitry is provided within each controller for producing control outputs which effect the energization and deenergization of the individual controllers. The compressors are turned on and off in sequence as the demand for compression respectively increases and decreases. The power-up delay period differs for each controller so that no more than one is energized at a given time when the system comes on line after a power failure or extended period of shut down.

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: An oil return system for a multiple compressor refrigeration system in which said compressors have a common discharge and at least two of said compressors have their low pressure suction side connected to operate at substantially different suction pressures, said oil return system having oil and refrigerant separating means connected to receive the common discharge from said compressors and oil delivery means constructed and arranged to maintain compressor oil levels at the suction side of the respective compressors, and oil control valve means disposed between said separating means and oil delivery means for each of said two compressors, said oil control valve means for each such compressor having pressure means for maintaining the downstream oil pressure to the oil delivery means at a preselected value.

Abstract: A heat pump having a plurality of compressors disposed in parallel is disclosed. An oil separator is disposed on the discharge sides of the compressors so as to separate any lubricating oil entrained in the refrigerant discharged from the compressors. The lubricating oil is accumulated in the oil separator and is then passed to an accumulator, from where it is returned to the compressors with returning refrigerant. Control means are provided for controlling the flow of oil from the oil separator into the accumulator. Rather than passing through the heat exchangers of the apparatus, the lubricating oil is quickly returned to the compressors from which it is discharged, thereby preventing oil shortages from developing in the compressors.

Abstract: A refrigeration unit (10) includes a temperature control circuit (42) in which a plurality of coils (32) are wrapped around associated compressors (24, 26, 28, 30, 38 and 40) and are arranged in parallel between a supply manifold (44) and a return manifold (46) so that as long as one of the compressors is operating, heat will be transferred into a working fluid flowing through the coils in order to heat any non-operating ones of the compressors. Further, during warm weather, any excess heat can be dissipated from the working fluid to a suitable heat sink as by use of a heat exchanger or any appropriate heat reclaiming process. In extremely cold environments, heat can be added to the working fluid in a suitable manner to maintain the fluid above a predetermined minimum level necessary to assure proper functioning of the compressors.

Abstract: A pump for compressing a low temperature high density liquid gas, e.g. liquid helium, wherein the piston is driven by a motor through a four bar linkage which converts rotary motion to reciprocating motion. The pump also includes an improved piston ring assembly, piston venting apparatus and a cushioned discharge valve. A two-stage pump in combination with support equipment provides an improved pumping cycle wherein low temperature density liquid or gas e.g. liquid helium can be withdrawn from a storage reservoir, vaporized and compressed into cylinders.

Abstract: An improved oil return system for use with closed circuit mechanical refrigeration systems having multiple compressors. The oil return system is responsive to the flow of refrigeration gas to the individual compressors and enables an optimum flow of crank case oil to each of the multiple compressors. The system is based on the use of oil pick-up means for each of the suction lines connected between the suction manifold and each of the compressors. This pick-up means comprises a venturi tube which provides for the flow of oil through each of the suction lines responsive to the flow of refrigerant gas therethrough. The venturi tube has an outlet end positioned in a downstream orientation with respect to the flow of refrigerant gas through a surrounding suction drop sleeve.

Abstract: A refrigeration system comprises an evaporator which feeds uncompressed vapor to a first (low) stage compressor, a second (high) stage compressor which receives low compression vapor from the first stage and feeds high compression vapor to a condenser, and a receiver which receives liquid from the condenser and ultimately feeds it to the evaporator. Desuperheater apparatus, comprising a pressure vessel (subcooler) and a heat exchanger, is provided to remove excess heat (superheat) from the compressed vapor fed by the first stage to the second stage to thereby improve thermal efficiency of the system and to reduce the mass of refrigerant to be handled by the second stage thereby enabling use of a smaller, more economical second stage compressor. The pressure vessel contains a bath of liquid which is supplied from the receiver and then fed to the evaporator.

Abstract: A lubricant distribution system for refrigeration units having a plurality of parallel compressors which system maintains the proper level of lubricant in the compressors during operation. The system comprises compressor suction inlet lines which connect each of the compressors of the system with a common suction header located at an elevation below the suction inlets on the compressors. The common suction header is connected to the evaporator outlet by a conduit which extends from the evaporator to the common suction header. The compressors suction inlet lines are sized to provide a suction gas mass velocity therethrough which is sufficient to carry lubricant into the compressors as an entrained liquid even when the compressors are operating at partial capacity.

Abstract: The present invention is a process for the liquefaction of high pressure natural gas. The natural gas is expanded through a turboexpander to reduce its pressure and thereby cool it. The natural gas is then passed through a demethanizer to remove the heavier components therefrom. The natural gas is then precooled, before substantial warming occurs, by heat exchange with a C.sub.2 hydrocarbon refrigerant, either ethane or ethylene, contained in a single refrigerant system. The precooled natural gas is liquefied by heat exchange with a mixed refrigerant contained in a mixed refrigerant system. The mixed refrigerant consists essentially of nitrogen, methane and a C.sub.2 hydrocarbon, either ethane or ethylene. The mixed refrigerant contained in the mixed refrigerant system is cooled by heat exchange with the C.sub.2 hydrocarbon refrigerant contained in the single refrigerant system.

Abstract: A transport refrigeration unit of the type which has a single or common refrigerant circuit, and a truck engine driven compressor 22 and a mutually, exclusively operable standby compressor 34 is provided with an arrangement of suction line fitting 46 with a pair of check valves 64 and 66 located physically above the fitting which receives the suction side refrigerant through line 48 from below the fitting and is provided with an inversely related pressure side fitting 54 with associated check valves 68 and 70 and the compressors are of substantially identical pumping capacity and oil capacity, all to the end of preventing an interchange of oil between the compressors during operation, and to migration of refrigerant and oil during periods of inoperation.

Abstract: A heat pump apparatus has a main refrigerant circuit constituted by a closed loop including a compressor, condenser, gas-liquid separator, pressure reducer such as an expansion valve, and an evaporator. A shunting refrigerant line having a compressor, condenser and a pressure reducer means shunts from the gaseous phase portion of the gas-liquid separator of the main refrigerant circuit and merges in the evaporator of the main refrigerant circuit. The shunting refrigerant line may be constructed to have one or more compression stages.

Abstract: Method and apparatus for recovery of waste heat from thermomechanical pulping systems and the like in which waste heat in the form of steam exhausted from the mechanical pulper and latency chest portions of the thermomechanical pulping system are respectively passed through first and second evaporators which increase the enthalpy of the working liquid. The working fluid outputted from the first evaporator passes through a first compressor to significantly increase both pressure and temperature and further increase enthalpy. The working fluid at the outlet of the first compressor then undergoes desuperheating within an intercooling tank. The liquid phase of the working fluid is passed from said tank to the inputs of both evaporators, while the vapor phase merges with the working fluid outputted from the second evaporator and enters a second compressor to undergo further increases in pressure and temperature.