Abstract: The invention resides in improvements to refrigeration systems which rely on circulation of refrigerant gas through compression and expansion phases, and thereby discharging heat from a fluid to be cooled. The invention includes a subcooler (38) in the refrigerant loop, downstream of the refrigerant condenser (34) and a gas trap (36) between the condenser (34) and the subcooler (38), that assures temperature drop in the subcooler (38). The invention also comprehends a shut-off valve (44) between the compressor and the heat source heat exchanger (28). The invention further includes a high capacity-to-volume oil to air heat exchanger (48), for cooling the lubricating oil in the oil loop (26). Preferred refrigerant is ammonia. Incorporating the above improvements into refrigeration systems enables an overall reduction in system sizing. Such systems, having heat exchange capacity of at least 200,000 Btu/hr., up to at least 500,000 Btu/hr.

Abstract: A muffler and an oil separator located within a common shell. The muffler includes a plurality of chambers tuned to different frequencies. The flow path is serially through the muffler into contact with an agglomerating pad followed by flow through demister pads and a coalescer.

Abstract: A refrigerant apparatus having a compressor, a condenser, an expansion value, evaporator and an oil repellent coat. An oil repellent coat is coated inside of a low pressure refrigerant passage which lubricant is easy to adhere so that lubricant is prevented from staying inside of the refrigerant passage. Since the oil repellant coat is low affinity for oil, luricant forms guttulate on the oil repellent coat by surface tension. Since the guttulate is easy to move on the inside wall with a flow of the refrigerant, it is prevented lubricant from staying on the inside wall.

Abstract: The normal path for the flow of oil/refrigerant being reclaimed from the cooler is changed during periods of low load operation such that the oil/refrigerant mixture flows directly from the cooler to the ejector rather than by way of normal suction housing pass. This is accomplished by valve means responsive to either a pressure differential or the guide vanes position, either of which is indicative of the load condition.

Abstract: An oil separator used in a refrigerating system. The oil separator comprises a body for forming a centrifugal oil separating chamber and an oil storage chamber, with a separating plate dividing the chambers. An inlet passage is connected tangentially to the oil separating chamber, to cause a swirl in the chamber, and a medium outlet passage extends inwardly from an end wall into the oil separating chamber. An oil outlet passage(s) is provided in the separating plate at a position near a periphery thereof. The oil separator body is formed integrally with the compressor housing and a ring member is fitted in an inner surface of the oil storage chamber, and a helically shaped narrow groove is provided on the outer surface thereof to form an oil returning passage. Also, the oil outlet passage can be provided in the separating plate at a position lower than a highest level of the oil storage chamber, thereby allowing the chambers to be arranged in a horizontal side by side relationship.

Abstract: A system and process of parallel compressors for compressing fluids miscible with oil. The present invention utilizes parallel-coupled compressors, wherein each compressor comprises a crankcase chamber, discharge chamber, suction chamber, and ejector which operate independent of one another. Means are provided for coupling the ejector in the return of the lubrication pump oil within the crankcase chamber and the maintenance of that oil level in all the crankcase chambers regardless of each compressor capacity and quantity with which they are operating or are not operating. The transference of suction chamber oil to crankcase chamber is performed by the ejector via energy from the lubrication pump contained within each crankcase chamber. Further, transference of oil from suction chamber to crankcase chamber via an ejector performs all necessary equalization functions.

Abstract: A helium gas compressing apparatus constructed in such as manner that: an oil separator in a high-pressure gas passage is connected to a low-pressure gas passage; and oil return path having first and second branch paths is provided between the high- and low-pressure gas passages; a capillary tube is installed in one of the two branch paths; and an adjustment valve is installed in the other branch path to adjust the pressure difference between the supply gas in the high-pressure gas passage and the return gas in the low-pressure gas passage. Because of this construction, the adjustment valve can be manipulated from outside to make fine adjustments on the pressure difference or change it to a desired value with ease even during operation of the apparatus, thereby adjusting the refrigerating capability of a helium refrigerating machine connected to the apparatus and the power consumption of the helium gas compressing apparatus.

Abstract: A device for separating oil from a gas is provided which includes a housing forming a peripheral wall with an inlet at a top end of the housing for receiving an oil/gas mixture, a gas outlet formed by a conduit extending through the top end of the housing and an oil outlet at a bottom end of the housing. Within the housing there is a helical wall extending between the gas outlet conduit and the peripheral wall to cause the oil/gas mixture to flow in a largely circumferential path along the peripheral wall. Between the helical wall and the peripheral wall there is provided a mesh screen for collecting and separating the oil from the oil/gas mixture. The collected oil drips from the screen to a baffle with apertures therein which directs the oil therethrough for receipt in an oil collection zone below the baffle. The gas outlet conduit has an opening above the baffle for permitting relatively oil-free gas to exit the oil separator.

Abstract: A capacity controllable compressor apparatus has a plurality of high-pressure chamber compressors which are connected in parallel to a common refrigerant suction pipe and a common refrigerant discharge pipe, and oil equalizing pipes through which oil sumps of the plurality of compressors are communicated with each other. One of the plurality of compressors is operated with its chamber kept at a higher internal pressure than other compressors.

Abstract: A refrigeration system (10) having a compressor rotor (20) rotatably supported by a plurality of hydrodynamic bearings (22 and 24) lubricated by oiless pressurized liquid refrigerant and pressurizing refrigerant which flows to a condenser (34) providing liquid refrigerant which flows to an evaporator (68) in fluid communication with the condenser and the compressor in accordance with the invention includes a refrigeration circuit (36) coupled to the compressor, for providing pressurized refrigerant to the hydrodynamic bearings from the compressor and to the evaporator; a bearing pump (26), coupled to the refrigerant circuit and to the condenser, for providing pressurized refrigerant to the refrigeration circuit; a first temperature sensor (101) sensing a temperature Tsink of a heat exchange fluid at the condenser and providing a temperature signal representative of the temperature Tsink of the heat exchange fluid at the condenser; a second heat exchange sensor (103) sensing a temperature Tsource of a heat exc

Abstract: A rotary displacement compression heat transfer system and method for improving its efficiency includes a rotary displacement compressor for compressing a refrigerant, a condensor connected with the outlet of the compressor, an evaporator connected with the inlet of the compressor, an oil pump for injecting oil into the compressor, an oil separator for separating out the oil and recirculating it to the compressor, a non-chlorinated hydrocarbon refrigerant, and a synthetic oil ingredient in the oil providing an inverse solubility characteristic where a mixture of the refrigerant and oil has two immiscible phases in the compressor's operating temperature range and has only one dissolved liquid phase at a temperature in the evaporator's operating range at a weight concentration of oil less than about 5%.

Abstract: An apparatus for dispensing a measured amount of hydroscopic lubricant into an air conditioning system. The apparatus includes a container for the lubricant which has a key type coupling to a cylinder. The cylinder has a piston which may reciprocate therein. The piston has a bore therethrough so that the lubricant may pass from the container and through the piston, and thereafter, through a hose and into the air conditioning system. The container has a seal to protect the lubricant from moisture, the seal being interrupted when the cylinder is coupled to the container. The cylinder has driven pins extending outwardly therefrom and the cylinder also has a pair of diametrically opposed slots therein. The piston has a pair of diametrically opposed drive pins thereon arranged so that the piston drive pins communicate with the slots in the cylinders. A detachable leveraged handle having arms joined in a scissor fashion is provided.

Abstract: A rotary displacement compression heat transfer system and method for improving its efficiency includes a rotary displacement compressor for compressing a refrigerant, a condensor connected with the outlet of the compressor, an evaporator connected with the inlet of the compressor, an oil pump for injecting oil into the compressor, an oil separator for separating out the oil and recirculating it to the compressor, a non-chlorinated fluorinated refrigerant, and a synthetic oil providing an inverse solubility characteristic where a mixture of the refrigerant and oil has two immiscible phases in the compressor's operating temperature range at a weight concentration of oil in the range of about 10-60% and has only one dissolved liquid phase at a temperature in the evaporator's operating range at a weight concentration of oil less than about 5%.

Abstract: The present invention provides a method and apparatus for recovering and purifying a refrigerant containing lubricant from a refrigerant system. The apparatus includes an evacuation means for evacuating the refrigerant and lubricant from the refrigerant system. A reservoir means receives the evacuated refrigerant and lubricant. A means allows lubricant and refrigerant to exit the apparatus and enter the refrigerant system.

Abstract: A lubricant composition with decreased solubility in a liquid refrigerant and increased foaming characteristics useful in refrigeration systems to promote oil return to a compressor. A lubricant composition comprises a base lubricant, synthetic paraffinic oil, and a foaming agent. These ingredients are blended in predetermined amounts, so that when the lubricant is used in the refrigeration system, an oil rich layer will form atop the liquid refrigerant in the system's flooded evaporator, and a thick, stable foam will form when vaporized refrigerant boils up through the oil rich layer. The oil foam is then drawn through a connection at the top of the flooded evaporator and returned to the compressor.

Abstract: This invention is comprised of an improved cryogenic refrigeration compressor which contains an externally adjustable relief valve positioned between the helium supply line and the helium return line whereby if the pressure within the helium supply line exceeds a predetermined value the externally adjustable relief valve opens up and allows helium to flow from the supply line to the return line. The relief valve is externally adjustable. It is comprised of a coaxial inlet and outlet member and externally adjustable spring compression means. Together they define a duct. Within the inlet member is a poppet valve and a spring. The spring exerts bias against the valve to close the valve against present fluid pressures.

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 first portion of a pitot tube-like device faces into the incoming stream of suction gas which enters the hermetic shell of a low-side reciprocating compressor. A second portion of the device extends downwardly toward the oil sump within the shell. The device terminates in a third portion which defines a plurality of apertures and which is immersed in the oil within the sump. The dynamic pressure or velocity head of the incoming suction gas stream is converted within the device to static pressure as a result of the resistance to flow through the device. The resistance to flow through the device is a function of, among other things, the static head at the immersed aperture locations.

Abstract: An air conditioner including a cooling medium compressor, a condenser, an expansion valve and an evaporator, these being connected one another by a cooling medium capillary tube to circulate a cooling medium, whereby an oil returning mechanism of an evaporator for the air conditioner is characterized in that there is provided an oil reservoir for reserving a lubricating oil after oil separation at a lower part of the evaporator, the oil reservoir and an outlet tube for guiding the cooling medium passed through the evaporator to the cooling medium compressor being connected by an oil returning tube, the oil returning tube being provided with a controlling valve, when a pressure differential between the oil returning tube and the outlet tube is a predetermined level or more, the controlling valve being closed to enhance a normal flow of the cooling medium from the evaporator to the cooling medium compressor, when the pressure differential is a predetermined level or less, the lubricating oil staying in the oil

Abstract: In a cryogenic refrigeration system, a hermetic refrigerant compressor pump is used to compress helium. The compressor pump 10 is oil cooled by a heat exchange jacket 46 surrounding a compressor housing 28. Oil from an oil sump 30 within the compressor housing 28 is pumped through an external heat exchanger 44 where it is cooled, to the heat exchange jacket 46. From the heat exchange jacket 46, oil is recycled back to the oil sump 30. Pressure developed by the compressor pump 10 is used to pump the oil.

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 combination superheater and oil separator for a refrigeration system having a rotary component, a source of heated medium and a source of non-superheated refrigerant gas-oil mixture includes a sealed casing, a heat transfer unit within the casing having a heat transfer surface, a connection from the interior of the casing to receive the mixture from the source, a connection from the heat source to supply heated medium at a temperature and heat transfer rate through the heat transfer surface to boil off refrigerant gas from the mixture and produce superheated refrigerant gas, a connection on the interior of the casing to deliver superheated refrigerant gas boiled off from the mixture in the interior of said casing, and a delivery conduit to deliver oil from the casing to the rotary component for lubricating the component with the nondiluted oil.

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 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: An oil return device for a refrigeration system which is placed in the suction line between the evaporator and the compressor to insure that the lubricant oil in the gases is returned to the compressor to prevent damage to the compressor. The device includes an inner tube within an outer tube each of which are connected to a tee fitting so that fluid flows downwardly between the two tubes and upwardly in the inner tube only. A venturi effect is produced at the end of the inner tube which speeds the fluid sufficiently to carry the oil along with the refrigerant.

Abstract: A compressor having an oil sump, an external oil reservoir, a conduit connecting the bottom of the oil reservoir to the compressor sump, a pump in the conduit for pumping excess oil from the reservoir to the compressor sump, and an overspill from the compressor sump back to the oil reservoir and a high side or a low side oil separator for removing oil from the refrigerant flow stream and returning it to the reservoir.

Abstract: A duplex compressor arrangement for shipboard application is provided with a central oil pickup to minimize the effects of trim on the sump. Additionally, the compressor crankcases are connected to the sump via return lines and equalizer lines which can act as secondary drain lines under the proper trim conditions.

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: A stop leak composition for sealing leaks in refrigeration systems and method for using same. A mixture of smooth surfaced particles having a size small relative to the leak size is suspended in refrigeration oil and injected into the refrigerant circuit of a system. The particles will be forced into small leaks and will agglomerate to seal the leak. Graphite particles and Teflon.RTM. particles in size ranges from 20 microns to 65 mesh are suitable.

Abstract: In a refrigeration system comprising a compressor, an oil separator, a condenser, an expansion valve, an evaporator, etc., a groove for oil separation is provided along inner wall of a refrigerant gas supply pipe which connects the oil separator and the compressor, and an oil reservoir is provided at the bottom of the oil separator.

Abstract: A cylinder is provided with a piston therein having a piston rod screw threadably engaging through one end cap so that rotation of the rod moves the piston along the cylinder. A filler is situated in the other end cap thus allowing the cylinder to be filled with refrigerant oil. An injection assembly is connected to the other end cap and includes a valve, a tube and a connector which may be connected to the high or low side of the refrigerant circuit of a refrigeration assembly such as an air conditioner. Once connected to the refrigerant circuit, a loosening of one union allows the refrigerant within the circuit to purge the line whereupon the union is tightened. The piston rod is marked with indicia along the length thereof so that rotation of the rod a predetermined distance indicates to the operator that a given amount of oil has been ejected from the cylinder and into the refrigerant system.

Abstract: A method for controlling the energization of a crankcase heater for use in a refrigeration circuit is disclosed. The crankcase heater is energized through normally closed relay contacts except when the compressor is operating and except for a delay period after compressor operation. A microprocessor control is utilized to calculate the delay period based on the length of the period of compressor operation and to control the energization of the crankcase heater.

Abstract: An oil control system and regulator for controlling the oil level in the crankcase of one or more refrigeration compressors or the like are disclosed. The regulator comprises a shell and end cap closures defining a closed chamber for containing the oil. An inlet extends through one of the end cap closures and includes a float controlled valve for admitting liquid to the chamber as necessary to maintain the oil level in the chamber and compressor crankcases and also includes a piston which is movable up and down to adjust the float and the oil level in the regulator chamber. A threaded adjusting pin extends through the end cap closure and into the chamber and threads on the adjusting pin are threaded through a coupling bracket which couples the pin with the piston to move the piston, float and valve for adjusting the oil level.

Abstract: A parallel operation compressor type refrigerating apparatus is disclosed which has first and second compressors connected in parallel with each other by a pipe, each having the inside of its crankcase separated into a motor chamber and a compressing element chamber by a partition provided with a pressure equalizing opening and a lubricant equalizing nonreturn valve allowing lubricant passage only from the motor chamber side to the compressing element chamber side, and which comprises a means provided at the end of a suction pipe of a refrigeration cycle system to separate the refrigerant gas circulating within the suction pipe into a lubricant and a gas, a first branch pipe to supply a portion of said gas to the first compressor, a second branch pipe to supply the rest of the gas and the lubricant to the second compressor, a pressure and lubricant equalizing pipe connecting together the lubricant sinks of the two compressors, and a nonreturn valve provided in the pressure and lubricant equalizing pipe to blo

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 lubrication system for use in a rotary compressor wherein the pressurized refrigerant fluid is passed through a precooler and returned to the compressor housing before passing through the discharge line to the refrigeration system. Oil entrained in the compressed precooled refrigerant is passed in heat transfer association with the rear head of the compressor to evaporate therefrom refrigerant vapor which may be entrained in the oil, permitting the oil to be returned to the lubrication sump after such removal for improved lubrication of the compressor. The rear head defines a lubricating oil flow path which, in the illustrated embodiment, opens upwardly from the rear head, permitting the lubricating oil to flow over the rear head for improved heat transfer association therewith in effecting the desired removal of entrained refrigerant vapor therefrom.

Abstract: Screw compressor 32 and screw expander 70 are connected into a refrigeration system. The system includes a mist lubrication system which drives oil particles suspended in flowing gas past the compressor and expander bearings for long life operation.

Abstract: In an apparatus for use for servicing air conditioning equipment, particularly in an automobile, the apparatus includes a container or cannister having a flow tube centrally located within it, extending from its upper closure member to within proximity of its base, with the upper section of the container being removable, and having a filter located therein. During usage, the container is useful for draining the refrigerant and lubricant from an automobile air conditioning system, with the refrigerant filtering through the filter, while the lubricant is collected within the container, and can be reused. The container also includes a magnetic member associated with the base to assure stable attachment of the apparatus to any metallic supporting surface during usage.

Abstract: In a large refrigeration system comprising a screw compressor of controllably variable output, compressor lubricating oil, discharged from the compressor in a mixture with compressed refrigerant, is separated from the refrigerant at an oil separator from which it is returned to the compressor. Compressed refrigerant flows from the separator, through a condenser, to a high pressure receiver, where it is held for circulation through an evaporator and thence back to the compressor.Through a bypass conduit in which a small liquid refrigerant pump is connected, condensed refrigerant from the receiver is delivered to a duct communicating the compressor discharge outlet with the oil separator inlet, to cool the oil-refrigerant mixture before it enters the separator. A thermostat senses temperature of that mixture near the separator inlet and so controls a throttling valve in the bypass conduit as to maintain that temperature substantially constant.

Abstract: In a refrigeration system wherein compressed refrigerant flows from a compressor discharge chamber successively through an oil separator and a condenser to a high pressure receiver, a minor portion of the condensed refrigerant that enters the high pressure receiver is passed through a pump by which its pressure is raised to above that of compressed refrigerant at said discharge chamber. From the pump the refrigerant is passed through an oil cooler in indirect heat exchange with compressor lubricating oil and is then released into the discharge chamber where it desuperheats the compressed refrigerant, thereby also cooling the compressor itself and increasing the effectiveness of the oil separator. The rate of flow of such refrigerant through the oil cooler is controlled to maintain a desired temperature of refrigerant flowing from the discharge chamber to the oil separator.

Abstract: A refrigerant system with a high speed centrifugal compressor has an arrangement for promoting the continuous return of oil to gear and bearing housing 12 including a coalescing type filter 62 from which separated oil is passed to a jet pump 74, a thermostatically controlled expansion valve 50 operating at a low superheat value, and inwardly pumping shaft seals 26.

Abstract: A refrigeration system employing oil lubricated compressors has an improved arrangement for removing oil contaminations from the hot gas contaminated with oil from the compressor. This is done by desuperheating the hot refrigerant gas with indirect contact cooling by flashing liquid at the condenser pressure, heating or evaporating water and heating air, and is applicable to all evaporative refrigerants: miscible and immiscible with lubricating oil.In addition, improved features for better contact of liquid and hot gas in present equipment by reducing density, improved inlet connection for receivers now in operation to minimize agitation, improved rapid defrosting by condensing clean gas with clean condensate remaining in the evaporator for chilling as the pressure is reduced, new non-entrainment trap for collecting non-condensible gases, and new application with siphonic tee utilizing high velocity gas from the compressor for drawing in gas at equalized pressure to be returned to the condenser.

Abstract: The disclosed system includes first and second hermetic shell compressors, one of which always runs while the system is operating and includes unloading means for running at half load, and the other compressor operating at full load or not at all so that four operating capacity steps are available, both of the compressors having shells with suction gas inlets, oil equalizer line ports, and gas exchange line ports being identically sized and located with respect to each other so that standard compressors can be stocked and used in the multiple compressor system while the multiple compressor system is capable of being operated at the varying capacities.

Abstract: A pressure switch for use in refrigeration systems which includes a restrictor to minimize the effect of compressor pulsations on the pressure sensing element and a heater positioned to warm the interior of the switch housing and to maintain the fluidity of refrigeration oil traversing the restrictor under conditions when the switch is exposed to low ambient temperatures.

Abstract: Refrigeration apparatus containing working fluid consisting essentially of refrigerant and lubricant, said refrigerant being halo-substituted hydrocarbon of 1 to 3 carbon atoms and at least 40% by weight fluorine and said lubricant being mixed branched chain alkylbenzenes having an average molecular weight in the range of from about 300 to about 470, said alkylbenzenes being produced by HF alkylation of benzenes with mixed polypropylenes.

Abstract: A high lift energy reclaiming circuit for use in a vapor compression refrigeration system, the circuit being interposed in the system between the compressor discharge line and the condenser inlet line. Refrigerant vapors discharged from the compressor are exposed to, and condensed into, a strong absorbent solution to develop temperatures within the mixture that are in excess of the saturation temperature of the discharge vapors. The mixture is brought into a heat exchanger where the high temperature energy is recovered by a heat reclaiming substance, such as water or the like. The diluted absorbent in the mixture is then separated from unabsorbed refrigerant vapors and the dilute solution flash cooled by expanding the solution to the inlet pressure of the compressor.

Abstract: A refrigeration plant including an oil-injected compressor, an oil separator, a condenser and an evaporator. The plant comprises means to introduce liquid refrigerant to the compression phase of the cycle ahead of the oil separator. The plant further comprises means to adjust the amount of liquid refrigerant introduced in response to the temperature difference between the condenser and the oil separator, in order to keep the difference on a constant level of 5.degree. C. to 15.degree. C.