US3277660A

US3277660A - Multiple-phase ejector refrigeration system

Info

Publication number: US3277660A
Application number: US513210A
Authority: US
Inventors: Clarence A Kemper; George F Harper; George A Brown
Original assignee: JOSEPH KAYE AND CO Inc
Current assignee: JOSEPH KAYE AND CO Inc
Priority date: 1965-12-13
Filing date: 1965-12-13
Publication date: 1966-10-11
Anticipated expiration: 1983-10-11

Description

Oct- 11, c KEMPER ETAL MULTIPLE-PHASE EJECTOR REFRIGERATION SYSTEM Original Filed Sept. 13. 1963 2 Sheets-Sheet 1 I03 IIO'\ 20 lOZ HEAT EXCHANGER 1 I v EVAPORATOR 2/ 26 3o 25 I3 p r' J FIGURE I 33 35 VAPOR COMPRESSOR FIS EVAPORATOR BOT 25 I2 HEATER 2| l9 J FIGURE 2 34 INVENTORS CLARENCE A. KEMPER GEORGE E HARPER GEORGE A. BROWN BYZ w ATTORNEYS Oct. 11, 1966 c. A. KEMPER ETAL 3,277,660

MULTIPLE-PHASE EJECTOR REFRIGERATION SYSTEM Original Filed Sept. 13, 1963 2 Sheets-Sheet 2 lOl H2 107 I03 0 H4 HI i I08 I I09 H3 7 k IOZ LIQUID-VAPOR 1 I SEPARATOR 32 VAPOR I COMPRESSOR |6 f 33 3| OMPRESSED VAPOR 26 I2 HEAT 22 i8 EXCHANGER f 24 28 EVAPORATOR HEATER l3 FIGURE 3 INVENTORS CLARENCE A-KEMPER GEORGE E HARPER GEORGE A-BROWN BY ATTORNEYS United States Patent 3,277,660 MULTIPLE-PHASE EJECTOR REFRIGERATION SYSTEM Clarence A. Kemper, Lexington, George F. Harper, Wayland, and George A. Brown, Lexington, Mass., assignors to Joseph Kaye & Co., Inc., Cambridge, Mass., a corporation of Massachusetts Continuation of applications Ser. No. 308,907, Sept. 13,

1963, and Ser. No. 489,107, Sept. 22, 1965. ThlS application Dec. 13, 1965, Ser. No. 513,210 33 Claims. (Cl. 62116) This is a continuation of of applications, Serial Numbers 308,907, filed September 13, 1963, and 489,107, filed September 22, 1965, both of which are now abandoned.

The present invention relates to improved apparatus for and methods of compression of refrigerant and other vapors, being more particularly related to an improved refrigeration system employing novel multiple-phase ejector apparatus.

Refrigeration systems commonly require a vapor compressor in order to condense the vapor from the evaporator at a higher temperature than that of the object or environment being cooled. Vapor compressors are generally characterized by being relatively high in cost, size and in operating noise level. We have now discovered an improved refrigeration apparatus and method that permits the replacement in whole'or part of the vapor compressor of conventional refrigeration systems by the employment of a novel multiple-phase ejector system having advantages of simplicity, small size, reliability, and a minimum number of moving parts.

In such vapor compressing systems, vapor which is generated by the evaporation of liquid at some desired temperature and pressure is compressed to higher pressure so that the heat introduced to the system at the temperature of the evaporation process may be rejected from the system at a higher temperature. The vapor in such systems is generally compressed by employing the above-mentioned mechanical vapor compressors, or vapor-driven ejectors, or liquid-driven ejectors. Our noval multiplephase ejector for compressing vapor, however, does not suffer from the operational limitations of such prior me chanical vapor compressor, and, in addition, is more efficient than vapor-driven and liquid-driven ejectors.

An ejector (sometimes called an injector, jet pump or jet compressor) is a device in which two fluid streams flow in intimate contact at relatively high velocity such that the driving stream transfers momentum to the driven stream, thereby increasing the stagnation pressure of the driven stream. The two fluid streams are accelerated in separate nozzles to approximately the same pressure before being brought together in a mixing section, and the mixed stream is decelerated in a diffuser. The principal sources of inefliciency in such ejectors are momentum transfer through large velocity differences and heat transfer through large temperature differences which exist between the driving and driven streams. In vapor compression systems, such as refrigeration systems and the like, the driven stream is vapor or a high-quality two-phase mixture at a relatively low temperature. If such driving stream is vapor or a high-quality two-phase mixture having approximately the same specific volume as the driven stream when the two streams enter the mixing section, there must be a large velocity difference between the two streams in order for the driving stream to transfer suf- "ice ficient momentum to the driven stream. If the driving stream is liquid, obtained from the condensation process of the cycle, there will be a large temperature difference between the driving stream and the driven stream providing for inefficient heat transfer between the two streams.

The multiple-phase ejector, however, utilizes low-quality, two-phase, liquid-vapor fluid as the driving stream. Before entering its nozzle and being accelerated, the driv ing stream may be compressed liquid, saturated liquid, or a low-quality, two-phase, liquid-vapor fluid. When the driving stream is a two-phase fluid at stagnation conditions, the driving stream nozzle may be either a simple convergent nozzle or it may be a convergent-divergent nozzle depending on the operating conditions of the cycle. When the driving stream is liquid at stagnation condiditions, however, the driving stream nozzle must, in accordance with our findings, be a convergent-divergent nozzle in order for the driving stream to be accelerated efficiently, and the driving stream becomes what We term a supersonic velocity stream, in that the square of the local average velocity is greater than the differential change of pressure with density in an isentropic expansion.

Hereinafter, the term liquid stream or liquid refrigerant stream will be employed to refer to a fluid stream which may be pure liquid or may be a low-quality, two-phase, liquid-vapor fluid being mostly liquid by mass; and the term vapor stream or vapor refrigerant stream will be employed to refer to a fluid stream which may be pure vapor or may be a high-quality, two-phase, liquid-vapor fluid, mostly vapor by mass.

When a multiple-phase ejector is employed as a vapor compressor in a vapor compression system, such as a refrigeration system, the driving stream is obtained from the ejector exit-stream by some process. The driving stream must have a higher stagnation pressure and a higher density than the ejector exit-stream. Since the ejector exit-stream is, in general, a two-phase, liquidvapor fluid, there are several processes by which a higherpressure, higher-density stream may be obtained. The ejector-exit stream may be condensed to form a pure liquid stream, part or all of which is pumped to a higher pressure by a liquid pump; the ejector-exit stream may be separated to form a liquid stream and a vapor stream with part or all of the liquid stream being pumped to a higher pressure by a liquid pump; or the ejector-exit stream may be separated to form a liquid stream and a vapor stream with part or all of the vapor stream being compressed to a higher pressure in a vapor compressor and subsequently being condensed to form a liquid stream. All of the processes above involve adding energy to the system in the form of work and yield a liquid stream which is at a stagnation pressure greater than that of the ejector exit-stream. In some applications, it may be desirable to add additional energy to the system in the form of heat by increasing the temperature of the liquid stream to a value higher than that of the ejector exitstream, and, if desired, partially to evaporate the stream at the higher temperature to form a low-quality, twophase driving stream. In the latter case, the quality of the partially evaporated stream should be such that it contains no more than substantially fifty percent vapor by mass.

In an ejector, the driving and driven streams enter the mixing section at approximately the same pressure. -In a multiple-phase ejector, the driving stream enters the mixing section as a low-quality, two-phase fluid, and the driven stream enters the mixing section as saturated vapor or as a high-quality two-phase fluid. When the same substance is employed in the two streams, therefore, they will enter the mixing section at approximately the same temperature, and any heat-transfer between the streams or between the liquid and vapor phases of any one stream will occur through small temperature differences, such process being thermodynamically more eflicient than heat-transfer through large temperature differences. Since the driving stream has a greater density than the ejector exit-stream, it will have a greater density, or lower specific volume, than the driven stream. The enthalpy change for a differential pressure change during an isentropic expansion is proportional to the specific volume of the fluid, and the velocity of a stream starting from rest and undergoing an isentropic expansion is proportional to the square-root of the enthalpy change experienced by the stream. Where the driving stream is accelerated from a high stagnation pressure and has a lower specific volume than the driven stream, it has been found possible to design a multiple-phase ejector such that the driving and driven streams enter themixing section at approximately the same values of velocity. The momentum transfer between the streams or between the liquid and vapor phases of any one stream will thus occur through small velocity diEerences--a process more efficient than momentum transfer through large velocity diiferences.

An object of the present invention, accordingly, is to provide a new and improved multiple-phase ejector system which is more efiicient than ordinary ejectors, because the inefliciencies due to heat-transfer and momentum-transfer are minimized.

Since the multiple-phase ejector is more efiicient than ordinary ejectors, refrigeration systems employing such a multiple-phase ejector as the vapor compressor will be more eflicient than refrigeration systems employing ordinary ejectors.

A further object of our invention, accordingly, is to provide a new and improved apparatus for and method of compression of refrigerant and other vapors.

Another object of our invention is to provide improved refrigeration systems and methods embodying the vapor compression apparatus and method abovementioned.

Other and further objects will be hereinafter explained and more fully delineated in the appended claims.

The invention will now be described in connection with the accompanying drawing, FIG. 1 of which is a combined partial cross-sectional view of a multiple-phase ejector and a block diagram of a preferred embodiment of a multiple-phase ejector refrigeration system;

FIG. 2 is a modification of portions of the system of FIG. 1, and

FIG. 3 is a combined cross-sectional view of a multiplephase ejector and a block diagram of another embodiment of a multiple-phase ejector refrigeration system.

Referring to FIG. 1, a multiple-phase ejector of a preferred type is illustrated at 100, having an input inlet 103 for the introduction of a high-pressure liquid stream communicating with a first nozzle 104 discharging into a mixing chamber 112 having its flow axis substantially aligned with the longitudinal axis of the nozzle 104. The nozzle 104 is contoured by respective converging-diverging

internal flow paths

105 and 109 in which the minimum cross-sectional area at 113 is sufficiently small relative to the outlet area and other dimensions at 108 as to enable the production of a supersonic, high-velocity, two-phase, liquid-vapor stream, as described previously. A second input inlet 102 is provided for the introduction of a lowpressure vapor stream communicating through a chamber 106 with a second nozzle 107 located substantially con- 4 p centric with the first nozzle 104 for introducing at 111 a high-velocity vapor refrigerant stream into the inlet opening of the mixing chamber 112 so as to be placed in intimate contact with the two-phase stream resulting at 108 from the first nozzle 104, thereby to combine the streams. The resulting mixed stream continues through the mixing section and a section 114 of substantially constant flow area into a diverging chamber 116, the function of the latter of which is to decrease the velocity of the combined streams at 110 to a velocity at which the temperature and the pressure of the combined stream is greater than the temperature and the pressure of'the vapor refrigerant stream prior to passage through the second nozzle 107. The divergent chamber 116 has an outlet at 101 from which the ejector-exit stream is withdrawn. The ejector-exit stream is at a higher pressure and a higher temperature than the vapor stream which was introduced at 102.

When the liquid stream introduced at 103 is substantially pure liquid, the nozzle 104 must be a converg-.

cut-divergent nozzle as shown. When the liquid stream introduced at 103 is a two-phase, liquid-vapor stream, the. nozzle 104 may be a convergent-divergent nozzle or may be a simple convergent nozzle. The nozzle 104 may be and preferably is a single nozzle as shown, or, if desired, ;a plurality of nozzles may be employed on one or more multiple-phase ejector inlet conduits; or a plurality of nozzles may be placed in any arrangement which permits the rapid and efficient introduction of a liquid stream and a vapor stream from

conduits

103 and 102, respectively, into the inlet opening of the mixing chamber 112. In the embodiment shown in FIG. 1, the liquid stream is introduced through the central nozzle 104 and the vapor stream is introduced through the concentric annular nozzle 107. The operation may also be effected by the introduction of the vapor stream through a central nozzle and the introduction of the liquid stream through a concentric annular nozzle.- In the embodiment shown, the multiple-phase ejector has-a mixing chamber 112 with an'inwardly sloping contour connected to the short section 114 of constant flow area. Mixing sections having geometries different from that shown may also be employed for use in the multiple-phase ejector.

The ejector-exit stream withdrawn at 101 may be and preferably is a twosphase, liquid-vapor fluid or, if desired, may be a completely condensed liquid stream con-. taining only trace amounts of non-condensible gases. The latter condition will find particular utility in rejection of heat from space vehicles where the absence of a gravitational field implies the need of a condensation process other than the conventional one which depends on the existence of a gravitational field for removal of the con-' densate from the condenser surfaces.

Referring again toFIG. l, a multiple-phase ejector.

refrigeration system is illustrated having, in one mode of operation, the multiple-phase ejector 100 of the type described above to which is introduced the high-pressure liquid stream at 103 and the low-pressure vapor stream at 102, and from which is withdrawn a single two-phase, liquid-vapor refrigerant stream at 101 having ahighen pressure and a higher temperature than the vapor stream at 102. The single stream withdrawn at 101 is applied through conduit 20 to a heat exchanger 22 in which 'the'j vapor portion of the stream is condensed," thereby re-. jecting heat from the system. The liquid stream withdrawn from the heat exchanger 22 through conduit 24' is divided into two portions; the first portion of which is applied through a conduit 26 to a'Jouleinson valve V or similar structure 28, whereby the stream is 'expanded to a lower pressure and is applied through conduit 30 to; anevaporator 18. The liquid is thus evaporated and, in so doing, absorbs heat from the environment-to-be-cooled.I The vapor withdrawn from the evaporator 18 through conduit 25 maybe applied either'directlyto' the'vapor inlet 102 of the multiple-phase ejector 100 through

conduits

16 and 35, as in FIG. 1, or along an alternative path through conduit 32 to a vapor compressor 31, FIG. 2, whereby its pressure is increased, and thence through

conduits

33 and 35 to the vapor inlet 102 of the multiplephase ejector 100.

The second portion of the liquid stream at 24, in FIG. 1, is applied through conduit 13 to a pump 14 which increases its pressure. The high pressure liquid at 15 is applied either directly to the liquid inlet 103 of the multiple-phase ejector 100 through

conduits

17 and 12, as in FIG. 1, or along an alternative path through conduit 19, FIG. 2, to a heater 34 and thence through

conduits

21 and 12 to the liquid inlet 103 of the multiple-phase ejector 100. When the heater 34 is employed, as in the modification of FIG. 2, the pump 14 serves the purpose of increasing the pressure of the liquid from the heat exchangeer 22 so that the liquid may be heated at 34 to a higher temperature, thereby accepting heat energy without evaporation. Once at such higher temperature, if desired, the fluid at 34 may be partially evaporated before introduction to the liquid inlet 103 of the multiple-phase ejector 100.

Thus, in one embodiment, the total energy-input to operate the system is introduced in the form of work by pump 14, in which case the vapor at 25 is applied directly through

conduits

16 and 35 to the vapor inlet 102 of the multiple-phase ejector 100, and the high pressure liquid at 15 is applied directly through

conduits

17 and 12 to the liquid inlet 103 of the multiple-phase ejector 100.

In the embodiment of FIG. 2, however, the energyinput to operate the system may be shared between the pump 14 and the heater 34, in which case the vapor at 25 is applied directly through

conduits

16 and 35 to the vapor inlet 102 of the multiple-phase ejector 100 and the liquid at 15 is applied through conduit 19 to the heater 34, whereby the temperature of the stream is increased, adding energy to the system in the form of heat, and thence through

conduits

21 and 12 to the liquid inlet 103 of the multiple-phase ejector. In this mode of operation, the liquid stream introduced at 103 may be pure liquid or may be a low-quality, two-phase, liquid-vapor fluid containing no more than about fifty percent vapor by mass and having a pressure greater than the desired pressure at the exit 101 of the multiple-phase ejector 100.

In still another embodiment, the energy-input to operate the system may be shared between the pump 14 and a vapor compressor 31, FIG. 2, in which case the high pressure liquid at 15 is applied directly to the liquid inlet 103 of the multiple-phase ejector 100 through

conduits

17 and 12 and the vapor at 25 is applied through conduit 32 to the vapor compressor 31 in which the pressure of the vapor is increased, thereby adding work to the system. The vapor leaving the vapor compressor 31 is applied to the vapor inlet 102 of the multiple-phase ejector 100 through

conduits

33 and 35. In this mode of operation the pressure at the exit 101 of the multiple-phase ejector is greater than the pressure of the vapor at 102 and less than the pressure of the liquid at 103.

In still another embodiment, the energy-input to operate the system may be shared among the pump 14, the heater 34 and the vapor compressor 31, in which case the vapor at 25 is applied through conduit 32 to the vapor compressor 31 in which the pressure of the vapor is increased (thereby adding work to the system), and thence through

conduits

33 and 35 to the vapor inlet 102 of the multiplephase ejector 100. The liquid at 15 is applied through conduit 19 to the heater 34, whereby the temperature of the stream is increased (adding energy to the system in the form of heat), and thence through

conduits

21 and 12 to the liquid inlet 103 of the multiple-phase ejector. As in the embodiments described above, in this mode of op eration the pressure at the exit 101 of the multiple-phase ejector 100 is greater than the pressure of the vapor stream at 102 and less than the pressure of the liquid stream at 103, and the liquid stream at 103 may contain no more than substantially fifty percent vapor by mass.

Referring to FIG. 3, a multiple-phase ejector refrigeration system is illustrated having a multiple-phase ejector of the same type described previously. The twophase, liquid-vapor stream at the exit 101 of the multiplephase ejector 100 is withdrawn through conduit 20 and applied to a liquid-vapor separator 30 whereby the stream is separated into a liquid portion and a vapor portion. The liquid portion is withdrawn from the liquid-vapor separator 30 through conduit 26 and is applied to the Joule- Thomson valve or similar structure 28, whereby the stream is expanded to a lower pressure and is applied through conduit 30 to an evaporator 18, thereby evaporating the liquid and in so doing absorbing heat from the environment-to-be-cooled. The vapor withdrawn from the evaporator 18 through

conduits

16 and 35 is applied directly to the vapor inlet 102 of the multiple-phase ejector 100.

The vapor portion is withdrawn from the liquid-vapor separator 30 through conduit 32' and is applied to a vapor compressor 31, whereby the pressure of the vapor stream in increased, adding energy to the system in form of work. The resulting high-pressure vapor is applied through conduit 33 to heat exchanger 22, in order to desuperheat and condense the vapor and to produce highpressure liquid at 24.

V The high-pressure liquid at 24 may be applied either to a path which introduces this liquid directly to the liquid inlet 103 of the multiple-phase ejector 100 through conduits 23 and 12, or it may be applied along an alternative path through conduit 13 to the pump 14 which further increases the pressure of the liquid.

The high-pressure liquid at 15 may be applied directly to the liquid inlet 103 of the multiple-phase ejector 100 through

conduits

17 and 12 or it may be applied along an alternative path through conduit 19 to a heater 34, whereby the temperature of the stream is increased, adding energy to the system in the form of heat, and hence through

conduits

21 and 12 to the liquid inlet 103 of the multiple-phase ejector.

In one mode of operation of the system shown in FIG. 3, the total energy-input to operate the system is introduced by vapor compressor 31 in the form of work as is typically done in conventional vapor-compression refrigeration systems. In this embodiment, however, an advantageous bootstrap type of operation takes place in accordance with which a saturated liquid stream is expanded to a lower pressure and temperature in order to absorb heat from an environment and in which the vapor so produced is introduced to the vapor compressor at a pressure higher than the saturation pressure corresponding to the temperature at which the heat was absorbed. Specifically, in the embodiment whereby the fluid applied to the liquid inlet 103 of the multiple-phase ejector 100 is previously passed through conduit 23, the saturated liquid leaving the heat exchanger 22 enters the nozzle 104 of the multiple-phase ejector in which its velocity is increased, thereby producing a two-phase, supersonic, liquid-vapor stream at 108. The vapor produced in the evaporator 18 enters the second nozzle 107 in which its velocity is increased, and the two streams are brought into intimate contact in the mixing chamber 112. The velocity of the combined stream is decreased in section 116 to provide a two-phase stream at the ejector exit 110 which has a higher pressure than the vapor which left the evaporator through conduit 16 and entered the ejector at 102. This two-phase stream then enters the liquidvapor separated 30 from which the liquid is drawn off through conduit 26 and from which the vapor is drawn off and introduced to the vapor compressor 31, whereby it is compressed to a higher pressure and temperature and returned by conduit 33' to the heat exchanger 22. The vapor introduced to. the vapor compressor 31 is at a higher pressure than the vapor produced in the evaporator 18. The liquid which was withdrawn through conduit 26 enters the Joule-Thomson valve 28 and is expanded to a lower pressure and temperature at 30 and enters the evaporator 18 in which it absorbs heat from the environment by evaporation to vapor at 16. In the typical refrigeration system, the liquid leaving the heat exchanger 22 would be passed immediately through the Joule- Thomson valve 28 into the evaporator 18 and the vapor generated in this evaporator and withdrawn through conduit 16 would be immediately introduced to a vapor compressor whereby it would be compressed to a higher pressure and temperature and re-introduced to heat exchanger 22. The pressure of the vapor at 16 is lower than that pressure generated by the multiple-phase ejector at 110.

Therefore, the vapor compressor 31, in this embodiment using the multiple-phase ejector, receives vapor at a higher pressure than does the vapor compressor of a typical refrigeration system operating with the same temperature in the evaporator 18. Less work, therefore, is required .to compress this vapor to the same pressure in the heat exchanger at 22.

In one embodiment illustrated in FIG. 3, the energyinput to operate the system may be supplemented by additional work-input through the pump 14, in which case the high-pressure liquid at 24 is applied to the pump 14 through conduit 13 and thence to the liquid inlet 103 of the multiple-phase ejector 100 through

conduits

15, 17 and 12.

In a further mode of operation of the system of FIG. 3, moreover, the energy-input to operate the system may be further supplemented by the addition of energy in the form of heat, in which case the high-pressure liquid leaving the pump 14 through conduit 15 is applied through conduit 19 to heater 34 and thence to the liquid inlet 103 cf the multiple-phase ejector 100 through

conduits

21 and 12.

The refrigerant fluid employed in the refrigeration systems described above may be any low boiling point, high heat capacity, condensable refrigerant fluid such as carbon dioxide, sulfur dioxide, water, ammonia, hydrocarbons, or'halohydrocarbons like mono and polychloro and fluoro substituted low molecular weight alkanes such as dichlorodifluoro methanes and trichloromonofiuoromethane and the like.

The refrigeration systems described above employ a single stage multiple-phase ejector, but these systems, as before noted, may, if desired, employ more than one multiple-phase ejector arranged in series or in parallel in order to compress the refrigerant vapor obtained from the evaporator 18.

Further modifications will also occur to those skilled in the art and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. An improved refrigerant process which comprises:

providing a high pressure liquid refrigerant stream at inlet means;

providing a low pressure vapor refrigerant stream at said inlet means;

increasing the velocity of the low pressure vapor refrigerant stream;

- increasing the velocity of the high pressure liquid re- ,frigerant stream and forming a supersonic velocity two-phase vapor-liquid refrigerant stream;

- mixing the two-phase vapor-liquid refrigerant stream with the increased velocity v-apor refrigerant stream to provide a single refrigerant stream;

decreasing the velocity of the said single refrigerant stream to a velocity at which the temperature and pressure of the same are greater than the temperature and pressure of the vapor refrigerant stream before its increase in velocity; 4 increasing the pressure of a portion of the said single refrigerant stream to provide the said high pressure liquid refrigerant; directing the high pressure liquid stream to said inlet means; expanding the remaining portion of the said single refrigerant stream to a lower temperature and pressure; and placing the expanded portion in a heat absorbent relationship with a heat source to provide said vapor refrigerant stream to said inlet means.

2. A process as claimed in claim 1 and in. which the said single refrigerant stream is condensed and the condensate divided into the said portion that is increased in pressure and the said remaining portion that is expanded.

3. A process as claimed in claim 1 and in which the said single refrigerant stream is separated into substantially liquid and vapor streams the latter of which comprises the portion that is increased in pressure and the former of which comprises the said remaining portion that is expanded.

4. A refrigeration system comprising, in combination:

inlet means for receiving a high pressure refrigerant liquid stream and a 'low pressure vapor refrigerant stream;

means for increasing the velocities of the streams including means for forming from the said liquid stream a supersonic velocity two-phase vapor-liquid refrigerant stream;

means for mixing the two-phase vapor-liquid refrigerant stream with the increased velocity vapor refrigerant stream to provide a single refrigerant stream;

means for decreasing the velocity of the said single refrigerant stream to a velocity at which the temperature and pressure of the same are greater than that of the vapor refrigerant stream at the said inlet means;

means for increasing the pressure of a portion of the said single refrigerant stream to provide the said high pressure refrigerant liquid and for directing the same to said inlet means;

means for expanding the remaining portion of the said single refrigerant stream to a lower temperature and pressure; and

means for placing the expanded portion in a heat: absorbent relationship with a heat source to provide the said vapor refrigerant stream to said inlet means.

5. A system as claimed in claim 4 and in which the said single stream is fed to heat exchanger means, the said pressure-increasing means comprises pump means connected to the heat exchanger means and the said expanding means comprises pressure expansion means connected with the heat exchanger means and connected through evaporator means with said inlet means.

6. A system as claimed in claim 5 and in which supplemental heater means is connected between the pump means and the said inlet means.

7. A system as claimed in claim 5 and in which vapor compressor means is. connected between said evaporator means and said inlet means.

8. A system as claimed in claim 4 and in which the said single stream is fed to liquid-vapor separator means the resulting vapor portion of which is fed to the said pressure-increasing means and the liquid portion of which is connected with the said expanding means.

9. A system as claimed in claim 8 and in which the pressure-increasing means comprises vapor compressor means-connected with heat exchanger means to the said inlet means.

10. A system as claimed in claim 9 and in which pump means is connected with or without supplemental heater means between the 'heat exchanger means and the said inlet means.

11. A system as claimed in claim 8 and in which the said expanding means comprises pressure expansion 9 means connected through evaporator means to said inlet means.

12. A vapor compressing apparatus which comprises,

in combination:

means for introducing a high-pressure liquid stream; means for increasing the velocity of the high-pressure liquid stream and producing a high-velocity supersonic two-phase liquid-vapor stream; 7

means for introducing a low-pressure vapor stream;

means for increasing the velocity of the low-pressure vapor stream;

means for combining said high-velocity, supersonic two-phase liquid-vapor stream and said low-pressure vapor stream, thereby to form a combined stream which is a two-phase stream and whose density is greater than the density of the low-pressure vapor stream and less than the density of the supersonic two-phase liquid-vapor stream; and

means for decreasing the velocity of said combined stream to a velocity at which the temperature and pressure of the combined stream is greater than the temperature and pressure which the low-pressure vapor stream had before its velocity was increased.

13. An apparatus as set forth in claim 12 wherein the means to increase the velocity of the high-pressure liquid stream is a convergent-divergent nozzle.

14. 'Refrigeration system which comprises, in combination:

an input for a liquid refrigerant stream of relatively high pressure;

an ejector comprising an elongated tube having a contoured internal fluid flow path including a mixing chamber with an inlet opening;

means for increasing the velocity of the relatively high pressure liquid refrigerant stream and producing a supersonic velocity two-phase liquid-vapor stream, said means comprising a first nozzle discharging into the inlet opening of said ejector and having a flow axis aligned with the longitudinal axis of the flow of said ejector;

means .to introduce the liquid refrigerant stream from the input to the first nozzle;

-a second nozzle located'concentrically with the first nozzle for introducing a high velocity vapor refrigerant stream into the inlet opening of the mixing chamber and placing stream into intimate contact withthe two-phase stream formed by the first nozzle, thereby to combine the streams;

means for decreasing the velocity of the combined streams in the said chamber to a velocity at which the temperature and pressure of the combined streams is greater than the temperature and pressure of the vapor refrigerant stream prior to passage through said second nozzle, the last-mentioned means comprising a divergent chamber .of said ejector tube leading from said mixing chamber;

liquid-vapor separator means connected to receive the output from the divergent chamber and to separate the same into liquid and vapor portions;

vapor compressor means connected to receive the separated vapor portion and to compress the same to a high pressure and temperature;

a heat exchanger to form a condensed refrigerant stream;

means to introduce the compressed vapor from the vapor compressor into the heat exchanger;

means to withdraw the condensed refrigerant stream from the heat exchanger and to introduce the same to the said input as the said liquid refrigerant stream of relatively high pressure;

an evaporator to form a vapor refrigerant stream;

means for receiving the said separated liquid portion of the liquid-vapor separator means to expand the same to a lower pressure and temperature;

10 means to introduce the lower pressure and tempera ture stream into the evaporator; and means to introduce the vapor refrigerant stream from the evaporator into the second nozzle. 15. The refrigeration system of claim 14 wherein pressure-increasing means is interposed in the path between the heatexchanger and the said input.

16. The'refirigeration system of claim 15 and in which further energy-supply means is interposed in the said path to increase the energy of the liquid refrigerant at the said input.

17. An apparatus for compressing a refrigereant vapor which apparatus comprises, in combination:

a pump to increase the pressure of a liquid refrigerant stream to a relatively high pressure;

means for increasing the velocity of the relatively high pressure liquid refrigerant stream and producing a supersonic velocity two-phase liquidwapor stream, said means comprising a first nozzle discharging into the inlet opening of said ejector and having a flow axis aligned with the longitudinal axis of the flow path of said ejector;

means to introduce the liquid refrigerant stream from the pump to the first nozzle;

a second nozzle located concentrically with the first nozzle for introducing a high velocity vapor refrigerant stream into the inlet opening of the mixing chamber and placing this stream into intimate contact with the two-phase stream formed by the first nozzle, thereby to combine the streams; and

means for decreasing the velocity of the combined streams in the said chamber to a velocity at which the temperature of the combined streams is greater than the temperature of the vapor refrigerant stream prior to passage through the second nozzle, the lastrnentioned means comprising a divergent chamber of said ejector tube leading from said mixing chamber.

18. The apparatus of claim 17, wherein the first nozzle is characterized bya contoured convergent-divergent internal flow path in which the convergence is sufficiently sharp and the minimum cross-section area sufficiently small to produce said supersonic stream.

19. The apparatus of claim 17, wherein the ejector tube has an internal section of substantially constant crosssection between the mixing chamber and the divergent chamber.

20. A refrigerant system which comprises in combination:

a pump to increase the pressure of a liquid refrigerant stream to a relatively high pressure; I

mean-s for increasing the velocity of the relatively high pressure liquid refrigerant stream and producing a supersonic velocity two-phase liquid-vapor stream, said means comprising a first nozzle dis-charging into the inlet opening of said ejector and having a flow axis aligned with the longitudinal axis of the flow path of said ejector;

a second nozzle located concentrically with the first nozzle for introducing a high velocity vapor refrigerant stream into the inlet opening of the mixing chamber and placing this stream into intimate contact with the two-phase stream formed by the first nozzle, thereby to combine the streams;

means for decreasing the velocity of the combined streams in the said chamber to a velocity at which the temperature of the combined streams is greater than the temperature of the vapor refrigerant stream prior to passage through said second nozzle, the lastmentioned means comprising a divergent chamberof said ejector tube leading from said mixing chamber; 1 a heat exchanger to form a condensed refrigerant stream; v. means to introduce the refrigerant stream from the divergent chamber into the heat exchanger; 71 means to withdraw a first portion of the condensed refrigerant stream from the heat exchanger and to introduce that portion to the pump;

i an evaporator to form a vaporrefrigerant stream;

means to withdraw a second portion of the condensed refrigerant stream from the heat exchanger and to expand that portion to a'lowerpressure and'temperature; v 7

means to introduce the lower pressure and temperature stream into the evaporator; and If means to introduce the vapor refrigerant stream'from the evaporator into the second nozzle. I

21. The refrigeration system of claim 20, wherein the means to introduce the vapor refrigerant stream from the evaporator to the second nozzle includes a vapor compressor. v

22. The refrigeration system of claim 20, wherein the first nozzle is characterized by a contoured convergentdivergent internal fluid flow path in which the'vconvergence is sumciently-sharp and the minimum cross-section area sufficiently small to produce said supersonic stream.

23. A process for compressing a vapor stream which process comprises: 7 ,s

- increasing the pressure of a liquid refrigerant. stream to a relatively high pressure; increasing the velocity of a vapor refrigerant stream; increasing the velocity of the pressurized liquid-refrigerant stream and forming a supersonic velocity twophase vapor-liquid.refrigerant stream therefrom; mixing the two-phase vapor-liquid refrigerantstream with the increased velocity vapor refrigerant stream; alld Y v decreasing the velocity of the mixedstreams toavelocity at which the temperature .of thefnixed streams is greater than the temperature of the vapor refrigerant stream before its increase-in velocity. 24. An improved refrigeration process which comprises:

increasing the pressure of a liquid refrigerants-stream to a relatively high pressure; 7

increasing the velocity of a vapor refrigerant stream;

increasing the velocity of the pressurized liquid refrig erant stream and forming a supersonievelocitytwophase vapor-liquid refrigerant stream therefrom; mixing the two-phase vapor-liquid refrigerant stream with the increased velocity refrigerant stream;

decreasing the velocity of the mixed streams to a velocity at which the temperature of the mixed streams is greater than the temperature .of the vapor refrigerant stream before its increase in velocity; condensing the mixed refrigerant streams";

recycling a first portion of the condensed streams as a liquid refrigerant stream; expanding a second portion of the condensed streams to a lower temperature and pressure; and placing the expanded second portion in a heat absorbing relationship with a heat source to provide .a first vapor refrigerant stream. 7

25. The process of claim 24, which includes compressing the vapor refrigerant stream prior to its increase in velocity.

26. The process of claim 24, wherein the vapor refrigerant stream is increased in velocity to form a twophase vapor-liquid stream and both two-phase streams have substantially the same temperature and pressure immediately prior to mixing.

j "27. 'An apparatus for compressing a refrigerant-vapor which apparatus comprises; in combination; I

. means for producing a liquid refrigerant stream of a relatively high pressure; f an ejector comprising an elongated tube having a contoured internal fluid flow path including a mixing chamber with an inlet opening; t means for increasing the velocity of the relatively high pressure liquid refrigerant stream and producing a supersonic velocity two-phase liquid-vapor stream, said means comprising a first nozzle discharging into the inlet opening of said ejector and having a flow axis aligned with the longitudinal axis of the flow path of said ejector; r means to introduce the liquid refrigerant stream to the .fi'rst nozzle; I fa second nozzle located concentrically with the first nozzle for introducing a high velocity vapor refrigrerant stream into the inlet opening of the mixing chamber and placing this stream into intimate contact with the two-phase stream formed by the first nozzle, thereby to combine the streams; and means for decreasing the velocity of the. combined streams in the said chamber to a velocity at which the temperature and pressure of the combined streams is'greater than the temperature and pressure of the vapor refrigerant stream prior to passage through the second nozzle, the last-mentioned means com- .prising a divergent chamber of saidejector tube leading from said mixing chamber. 4 28. The apparatus of claim 27, wherein the first nozzle is characterizedby a contoured convergent-divergent internal flow pathin which the convergence is suificiently sharp and the minimum cross-section area sufficiently small to produce said supersonicstre-am. 29. The apparatus of claim 27, wherein the ejector tube hasv an internal section of substantially constant cross-section between the rnixingchamber sand the divergent chamber. I

30. The apparatus of claim 27, wherein there isfurther i provided; n

a heat exchanger to form a condensed refrigerant stream; t p means to introduce the refrigerant stream from the divergent chamberinto the heat exchanger;

means to withdraw a first portion ofthe condensed refrigerant stream from the heat exchanger. and to introduce that portion to the said first nozzle;

an evaporator to form a vapor refrigerant stream;

means to withdraw a second portion of the condensed refrigerant stream from the heat exchanger and to expand that portion to a lower pressureand temperature; t r means tofint-roduce thelower pressure and temperature stream into the evaporator; and v a means to; introduce the vapor refrigerant stream from .the evaporator. into the said second nozzle.

31. The refrigeration system of claim 30,- wherein the means to introduce the vapor refrigerant streamfrom theevapora-tor to the second nozzle includes a vapor compressor.- H 4 Y 32. A process for compressing a vapor stream which process comprises: 1 a r producing a liquid refrigerant stream of a relatively highpressure-',--"

increasing thevelocity of a vapor refrigerant stream;

- increasing the velocity of the pressurized-liquid refrigcram-stream and forming a supersonic velocity twophase vapor-liquid refrigerant stream therefrom;

mixing the two-phase vapor-liquid refrigerant stream with the increased-velocity vapor refrigerant stream;

" and-0' decreasing the velocity of the-mixed streams to a velocity at which the temperature of the mixed streams is greater than the temperature of the vapor refrigerant stream before its increase in velocity.

33. A process as claimed in claim 32 and in which the following further steps are performed:

condensing the mixed refrigerant streams;

recycling a first portion of the condensed streams as a liquid refrigerant stream;

expanding a second portion of the condensed streams to a lower temperature and pressure; and

placing the expanded second portion in a heat absorbing relationship with a heat sourceito provide a first vapor refrigerant stream.

References Cited by the Examiner UNITED STATES PATENTS Seligmann 62500 Kallam 62-169 X Randel 62-500 X Randel 62-500 Linbolm 62 121 X Neumann et a1. 62S00 LLOYD L. KING, Primary Examiner.

Claims

32. A PROCESS FOR COMPRESSING A VAPOR STREAM WHICH PROCESS COMPRISES: PRODUCING A LIQUID REFRIGERANT STREAM OF A RELATIVELY HIGH PRESSURE; INCREASING THE VELOCITY OF A VAPOR REFRIGERANT STREAM; INCREASING THE VELOCITY OF THE PRESSURIZED LIQUID REFRIGERANT STREAM AND FORMING A SUPERSONIC VELOCITY TWOPHASE VAPOR-LIQUID REFRIGERANT STREAM THEREFROM; MIXING THE TWO-PHASE VAPOR-LIQUID REFRIGERANT STREAM WITH THE INCREASED VELOCITY VAPOR REFRIGERANT STREAM; AND DECREASING THE VELOCITY OF THE MIXED STREAMS TO A VELOCITY AT WHICH THE TEMPERATURE OF THE MIXED STREAMS IS GREATER THAN THE TEMPERATURE OF THE VAPOR REFRIGERANT STREAM BEFORE ITS INCREASE IN VELOCITY.