US3563054A - Refrigeration system with liquid separator - Google Patents

Abstract

D R A W I N G
A REFRIGERATION SYSTEM WHEREIN A CONVENTIONAL COMPRESSOR OR A GENERATOR BOILER IS REPLACED BY A NOVEL LIQUID VAPOR PHASE SEPARATOR AND A SMALL CAPACITY VAPOR PUMP, SAID LIQUID VAPOR PHASE SEPARATOR BEING THERMALLY INSULATED AND HAVING HEAT TRANSFER MEANS WITHIN TO LOWER AND CONTROL THE OPERATING TEMPERATURE OF THE LIQUID VAPOR PHASE SEPARATOR, SAID VAPOR PUMP SERVING TO EVACUATE VAPOR FROM THE SEPARATOR AND DELIVER IT TO A CONDENSER TO CONDENSE IT AND SUBSEQUENTLY DELIVER IT TO A RECEIVER, SAID LIQUID PUMP DRAWING LIQUID REFRIGERANT FROM THE SEPARATOR AND DELIVERING IT TO THE RECEIVER.

Description

Feb. 16, 1971 F LOFGREEN ET AL 3,563,054

REFRIGERATION SYSTEM WITH LIQUID SEPARATOR Filed Dec. 51, 1968 2 Sheets-Shag .Ikuen for s Haw/6y Z. bygbarn fl)? d/ewflo/yre er) Azzorne Feb. 16, 1971 A. F. LOFGl QEEN ET AL 3,563,054

REFRIGERATION SYSTEM WITH LIQUID SEPARATOR Filed Dec. 31, 1968 2 Sheets-Sheet 2 7'0 Pe cve er 7'0 Pec/euer For .ZZ/apora 3,563,054 REFRIGERATION SYSTEM WITH LIQUID SEPARATOR Andrew F. Lofgreen and Harley L. Coggburn, both of R0. Box 948, Big Bear Lake, Calif. 92315 Filed Dec. 31, 1968, Ser. No. 788,295 Int. Cl. F25b 43/00 US. Cl. 62-512 6 Claims ABSTRACT OF THE DISCLOSURE A refrigeration system wherein a conventional compressor or a generator boiler is replaced by a novel liquid vapor phase separator and a small capacity vapor pump, said liquid vapor phase separator being thermally insulated and having heat transfer means within to lower and control the operating temperature of the liquid vapor phase separator, said vapor pump serving to evacuate vapor from the separator and deliver it to a condenser to condense it and subsequently deliver it to a receiver, said liquid pump drawing liquid refrigerant from the separator and delivering it to the receiver.

This invention relates to a new and improved refrigerating system or apparatus and is more particularly concerned with such a system utilizing both absorption and compression principles.

In general, thermally operated or absorption type refrigeration systems have been of questionable success because of an inherently, relatively low coeificient of performance. A major shortcoming of absorption type systems resides in the large quantities of rejected heat and the requirements of bulky accessory equipment, such as condensers, cooling towers and the like.

Further, absorption type refrigeration systems are normally such that they must be carefully and accurately installed and set, to the end that they are, in addition to being inefficient, unsuitable for use in automobiles or other like installations where minimal space is available and where the systems are subjected to being moved about and their positions varied.

In general, compression type refrigeration systems are more versatile than absorption type systems and are such that they can be made relatively small and compact and are unaffected by movement or change in position. Accordingly, this type of system is suitable for and finds wide use in automotive air conditioning systems or units. The principal shortcoming in compression type systems resides in the fact that a large, heavy and inefficient compressor and large, costly condensing coils, or the like, must be provided.

In the case of the ordinary automotive air conditioning unit, utilizing the compression system, a compressor is driven by the automobile engine. Such compressors normally require from ten to fifteen horsepower, from the engine, to effect operation of the refrigeration system.

It is an object of our invention to provide a small, neat, compact refrigeration system which includes a fractional horsepower liquid circulating pump and a fractional horsepower vacuum pump related to a liquid vapor phase separator, which pumps and separator replace the compressors or the generators of conventional refrigerator systems and which materially reduce the condenser capacity required in conventional refrigeration systems of similar output. The system that we provide requires less than the power input and less than A the condenser capacity of a conventional automotive type refrigeration system of like output or cooling capacity.

It is an object and feature of our invention to provide United States Patent 0 a refrigeration system of the character referred to wherein the liquid vapor phase separator is a simple tank like structure of small dimensions and of economical construction which serves to receive liquid refrigerant from a related evaporator, to collect and hold the refrigerant for extraction therefrom and transfer to a related receiver by means of the liquid pump. Further, the liquid-vapor phase separator serves to separate gaseous refrigerant received from the evaporator and entrained in the liquid refrigerant, to contain it for extracting from the separator and delivery to a related condenser by means of the vacuum pump, said condenser being connected with the receiver to deliver its condensates thereto.

A further object and feature of our invention is to provide a liquid-vapor phase separator of the character referred to wherein certain of the liquid refrigerant boils off or vaporizes as a result of the pressures generated by the vacuum pump extracting vapor therefrom and which includes heat transfer means which serve to effect absorption of heat from the refrigerant flowing into the separator by the vapor in and flowing from the evaporator whereby the temperature of the infiowing refrigerant is lowered and its liquid state more stabilized and whereby the volume of gaseous refrigerant flowing into and out of the separator is maintained at a small controlled amount or volume, thereby materially reducing the capacity requirements of the vacuum pump and the condenser.

It is an object of the present invention to provide a refrigeration system of the character referred to wherein the liquid vapor phase separator is a thermally insulated unit whereby the function and operation of the unit is unaffected by changes in temperatures of the ambient air and the like and so that its internal operating temperature is maintained below the boiling point or latent heat of vaporization of the refrigerant.

Another object of the instant invention is to provide a system of the character referred to in which the liquid vapor phase separator serves as -a cooler means to cool and assist condensing of the vaporous refrigerant extracted from said separator by the vapor pump and discharged by said vapor pump.

The foregoing and other objects and features of our invention will be fully understood ad will become apparent from the following detailed description of typical preferred forms and applications of our invention, throughout which description reference is made to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of our new system;

FIG. 2 is a diagrammatic view of a portion of our system and showing a modification;

FIG. 3 is a diagrammatic view of a portion of the structure shown in FIG. 2 of the drawings and illustrating yet another modification.

The apparatus and system that we provide includes a plurality of interconnected and related refrigerant handling and conducting components, parts and means, and defines a circuit having high and low pressure sides.

The high pressure side of the circuit includes a condenser C, a receiver R, and an expansion valve V.

The lower pressure side of the circuit includes an evaporator E and liquid vapor phase separator A.

The evaporator E is shown as a direct expansion type evaporator coil having an inlet end 10 connected with the expansion valve V of the high pressure side of the system and into which liquid refrigerant is introduced, to fiow therethrough, expand partially or totally into vapor and/ or gas, and to thereby absorb heat from the ambient atmosphere.

The evaporator E has an outlet or discharge end 11 which is connected with the liquid vapor phase separator A.

The liquid vapor phase separator A consists of a closed tank or vessel 12 with upper and lower ends 13 and 14, liquid outlet means at its lower end, vapor outlet and liquid inlet means at its upper end and related heat transfer means.

The liquid outlet means at the lower end of the tank 12 is adapted to collect liquid deposited in the tank and direct or conduct it to a related liquid pump L. In the case illustrated, the liquid outlet is in the nature of a sump 15 in the bottom of the tank and in which a portion of the pump L is engaged.

The vapor outlet means at the upper end of the tank can be a simple opening in the tank and with which a suction line 16 extending to a vapor pump P can be suitably connected, or can, as illustrated, be an opening in or at the outer end of an elongate, tubular vapor conducting neck 17 projecting upwardly and/or laterally from the top or upper end of the tank with an opening at its outer end to connect with the line 16 and which forms a part or portion of the heat transfer means.

The liquid inlet means and the related heat transfer means of the liquid vapor phase separator A are established by a common elongate, tubular liquid and/or gas conductor 18 having an outer inlet end portion 19 connected with the outlet end 11 of the evaporator coil E as at 20 and an elongate inner end portion 21 in the form of a coil or condensing tube entering into the upper end of the tank and extending downwardly and about the interior thereof to terminate and open at the lower or bottom end of said tank. The coil or condensing tube 21 is shown integrally joined with the conductor 18 and is shown as being divded into two branch-like downwardly extending coils 22 in the tank.

The inlet end portion 19 of the conductor 18 can extend through an opening in the top of the tank 12 or can, as illustrated, extend longitudinally through the neck 17 on the tank and thence through a suitable opening in the outer end thereof to connect with the evaporator E.

It is to be noted that the inner end portion or coils 22 of the conductor 18 and the outer portion 19 thereof, extending through and cooperating with the jacket-like tubular neck 17 on the tank establish an effective transfer of heat between the liquid and/or vaporized refrigerant within the conductor 18 and the vaporized refrigerant (in the tank and neck) about the conductor.

The tank 12 of the liquid vapor phase separator A and in the case illustrated the neck 17 thereof and preferably the suction line 16 are suitably thermally insulated. In the preferred carrying out of the invention, the insulation about the noted structure is established of preformed Styroform sections. In practice, any suitable form of insulation can be employed.

The liquid pump L related to the liquid outlet means or sump 15 of the liquid vapor phase separator A is, preferably, a positive displacement type of liquid pump with an inlet side in direct communication with the sump or liquid outlet means and with an outlet side connected to and with the receiver by a delivery line 23.

The pump L is adapted to extract liquid refrigerant from the tank 12 and deliver it to the receiver R and in doing so establish a minus pressure in the tank 12 and a positive pressure in the receiver R and to establish and maintain circulation of refrigerant in the system. It is not a compressor. Accordingly, the pump L need not be a powerful, high volume pump, but need only be capable of establishing or maintaining the systems high pressure and to keep up with and maintain the circulatory rate of refrigerant through the system. In practice, the pump L can be driven by any suitable prime mover and in the preferred carrying out of the invention is driven by a fractional horsepower electric motor, for example an A housepower motor M.

The vapor pump P can be of any type or design of pump suitable for moving gases and vapors, such as a vane type or diaphragm type of pump. The pump P can be driven by any suitable prime mover and, in the preferred carrying out of the invention, is driven by a fractional horsepower electric motor, for example, a 41 horsepower motor M.

The suction or inlet side of the pump P is connected with the liquid vapor phase separator A by the suction line 16 as noted above and its outlet or discharge side is connected with the inlet end of the condenser by a discharge line 24.

The condenser C is preferably a simple coil type condenser or heat exchanger and has its outlet end connected with the receiver R by a return line 25.

In operation, the pump P serves to draw or extract vapor from the upper portion of the tank 12 and neck 17 of the liquid vapor phase separator A and deliver said vapor into the condenser C for condensing and subsequent flow, through the line 25 and into the receiver R.

In effecting the above, the pump P assists the liquid pump L in establishing and maintaining a sufficiently low pressure in the tank 12 of the liquid vapor phase separator A to maintain desired flow inducing pressure therein and at the outlet end of the evaporator E.

The minus pressure established in the tank 12 causes some boiling off or vaporization of the refrigerant in the tank, which vaporization results in a material drop in the temperature of the refrigerant in the upper portion of the tank and neck 17 thereof and resulting absorption of heat and further condensing and/or cooling of the refrigerant flowing from the evaporator E and through the portions 19 and 21 of the conductor 18.

In practice, the cooling and condensing effect of the heat transfer means in the liquid vapor phase separator A is effective to lower the temperature of the refrigerant sufficiently so that the rate of boil off or vaporization of the refrigerant therein is rather limited and establishes a balanced and controlled condition. This balanced, low rate of boil off or vaporization is maintained in part by the thermal insulation I provided.

It will be further noted that as a result of the above, the capacity of the vapor pump P and the capacity and size of the condenser C is extremely lower and maintained at a minimum.

The receiver R is a simple closed tank with two inlet openings with which the lines 23 and 25 are connected and an outlet opening in and through which the inlet end of a flow line 26 extends. The inlet end of the line 26 opens at the bottom or lowermost side of the receiver to assure that only liquid refrigerant will enter and flow through said line.

The other or discharge end of the How line 26 connects with the inlet side of the expansion value V.

The other or outlet side of the valve V connects with the inlet end 10 of the evaporator E.

In practice, the expansion valve V could be replaced by a capillary tube without departing from the spirit of this invention.

With the structure described in the foregoing, it will be apparent that a complete and closed circuit or system is provided.

In the preferred carrying out of the invention, a suitable check valve 27 is arranged in line 25 to prevent possible surges in pressure in the receiver R from establishing a reverse flow of refrigerant in the line 28 and condenser C.

It is to be noted that the pumps L and P serve to generate some heat in the system, which heat is effective in enhancing the operation of the system.

In a 4 ton system, as shown in the dawings, and described above, with A and 43 horsepower liquid and vapor pumps and charged with Freon #12, the temperature and pressure of the Freon in the receiver R and at the high pressure side of the expansion valve is between and p.s.i. At the discharge side of the expansion valve and through the evaporator E, the temperature and pressure drops to about 40 (+20", 5). The pressure in the separator is at about 40 p.s.i. and the temperature of the refrigerant therein is variable and is believed to drop to as low as -30. At the inlet side of the vapor pump P the pressure of the refrigerant is equal to the pressure within the separator which is about 40 p.s.i. and at a relatively low temperature. The temperature of the refrigerant discharged by the pump P is heated by the work of the pump and is discharged into the line 24 at increased temperature and at a pressure materially greater than the pressure at the intake of said pump and greater than the pressure in the receiver R.

In light of the above, it will be apparent that an extremely effective and desirable temperature and/or pressure differential is maintained between the high and low pressure sides of the system, which differential is such as to assure the desired heat exchange at the evaporator E.

In accordance with common practice, the system can be provided with a dryer 40 and sight glass 41. In the case illustrated, dryer and sight glass are arranged in the line 26.

In practice, the system can be provided with any suitable control means. In the case illustrated, the system is under control of a master switch 50, which switch controls the flow of current to the motors M and M for the pumps L and P and to the motor M of a blower X related to the evaporator.

The motor for the pump L is preferably a two-speed motor and such that it will normally run at full speed and is such that it can be shunted to operate at half speed, thereby reducing the rate of flow of refrigerant issuing from the pump L and flowing through the system, when the system reaches operating temperature and so the system will not hunt.

The motor M of the pump L is under control of a twoway pressure responsive switch 51 engaged in the line 26 and suitably connected with the master switch 50.

Since the details of the control means can vary widely without departing from or affecting the spirit of the invention, we will not burden this disclosure with further details of the control means shown or of other alternative and more complicated control means that have proven satisfactory.

In FIG. 2 of the drawings we illustrate a portion of our system wherein the several parts and portions illustrated are identified by the same reference characters identifying similar parts and portions in the system illustrated in FIG. 2.

In FIG. 2 the system is modified so that the liquid vapor phase separator, in addition to functioning and performing the functions set forth above, also serves to supplement the function of the condenser C, by cooling the discharge of the refrigerant flowing through the condenser to the receiver.

In the second or modified form of the invention, the return line 25, downstream of the check valve 27 is provided with a coil portion 25' wound about and down the exterior of the tank T in heat conducting contact therewith and between the tank and insulation I.

The coil portion 25 in combination with the tank 12 establishes a heat exchanger which further cools and condenses the discharge of the condenser C and also provides a limited amount of heat to the liquid vapor phase separator A to assist the operation of the separator A with respect to boiling off or vaporizing of the refrigerant therein to achieve the desired cooling effect.

It will be apparent that in this second form of the invention, where the separator A also serves to cool and condense the discharge of the vacuum pump, the separator A must be designed and proportioned so that it continues to function its primary or principal functions and the noted added cooling function.

It will be further apparent that the coil portion 25' and the heat exchanging function performed thereby materially reduces the capacity demand of the condenser C, making it possible and practical to provide a system with an extremely small capacity condenser or a system In accordance with the foregoing, in FIG. 3 of the drawings we illustrate a portion of yet another form of our invention where the condenser C is eliminated and a minimum capacity finned conductor type of heat exchanger or condenser C is provided in its place.

In practice, the heat exchanger C can consist of a length of heat absorbing and radiating wire wrapped helically about the exterior of the line 24, which line is connected directly to its check valve 27.

Having described only typical preferred forms and applications of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any modifications and/or variations that may appear to those skilled in the art.

Having described our invention, we claim:

1. A refrigeration system of the character referred to including an evaporator with an inlet and an outlet, refrigerant expansion means connected with the inlet, a receiver, a delivery line between the receiver and the expansion means, a liquid vapor phase separator including a closed tank having upper and lower ends, a thermal insulating means about the tank and insulating said tank from ambient temperature, a liquid pump with an inlet side connected with the lower end of the tank and an outlet side connected with the receiver, a vapor pump with an inlet side connected with the upper end of the tank by a suction line, condenser means connected between an outlet side of the vapor pump and the receiver, and a flow line between the outlet of the evaporator and the tank, said liquid vapor phase separator including heat transfer and condensing means within the tank to effect transfer of heat between the vapor in the tank and the refrigerant flowing from the evaporator into the tank.

2. A system as set forth in claim 1 wherein said heat transfer and condensing means includes a condensing tube communicating with said flow line and extending downwardly through the interior of the tank to terminate and open at the lower end of the tank.

3. A system as set forth in claim 1 wherein said heat transfer and condensing means includes a condensing coil communicating with the flow line and extending from the upper portion of the tank downwardly in and about the interior of the tank to terminate and open at the lower end of the tank.

4. A system as set forth in claim 1 wherein said heat transfer and condensing means includes a tubular extension on the upper portion of the tank and communicating with the interior thereof and a condensing tube communicating with the flow line and extending longitudinally through the extension and thence into the tank, said suction line connected to the end portion of the extension remote from the tank.

5. A system as set forth in claim 1 wherein said heat transfer and condensing means includes an elongate tubular extension on the upper portion of the tank and communicating with the interior thereof and a condensing tube communicating with the flow line extending longitudinally through the extension and a coil communicating with the condensing tube and extending downwardly and about the interior of the tank to terminate and open in the lower portion thereof.

6. A system as set forth in claim 5 wherein said tank extension and suction line are thermally insulated from ambient temperature.

References Cited UNITED STATES PATENTS 2,986,898 6/1961 Wood 62512 3,067,590 12/ 1962. Wood 62-512 3,315,484 4/1967 Ross 62-403 3,353,367 11/1967 Garland 62-174 MEYER PERLIN, Primary Examiner

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