US1953993A

US1953993A - Absorption refrigeration

Info

Publication number: US1953993A
Application number: US490497A
Authority: US
Inventors: Donald G Smellie
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1930-10-22
Filing date: 1930-10-22
Publication date: 1934-04-10
Anticipated expiration: 1951-04-10

Description

April 1 0, 1934. D, SiMELLIE 1,953,993

ABSORPTION REFRIGERATION Filed 001;. 22, 1950 2 Sheets-Sheet 1 porzald 6'. Jm I April 10, 1934. SMELLIE 1,953,993

ABSORPTION REFRIGERATION 'Fild-Oct. 22, 1930 2 Sheets-Sheet 2 Men/02 M 726 55-- R ,Domfl 6- Jmflz my I I I Patented Apr. 10,- 1934 ABSORPTION REFRIGERATION Donald G. Smellie, Canton, Ohio, assignor to The Hoover Company,North Canton, Ohio, a corporation of Ohio Application October 22, 1930, Serial No. 490,497 22 Claims. (01. 62119.5)

This invention relates to refrigerating apparatus and more particularly to systems of the type in which an inert gas is employed as. a pressure equalizing medium so that the total pressure therein is substantially the same throughout the system, but the partial pressure of the refrigerant differs in different parts so as to enable the refrigerant to evaporate and produce a cooling effect at a lower temperature than that at which it is changed to a more dense phase.

As disclosed in the United States patent to Geppert 662,690, a continuously acting refrigerating system may be constructed and operated without the use of an expansion valve or the like provided an inert gas is employed as a pressure equalizing medium in certain parts of the system. This principle, which is now well known,

- is employed in obtaining a cooling effect in accordance with the present invention although the 20 manner in which it is used, and the process as a whole differs widely from that suggested by Geppert.

This application contains subject matter in common with my prior co-pending application,

25 Serial-No. 169,765, filed February 21, 1927, for

Refrigeration, now Patent No. 1,818,587, patented August '11, 1931, so that it relates back thereto insofar as the common subject matter is concerned.

An object of the present invention is to provide a continuous absorption refrigerating system employing an inert gas and operating upon a new principle in which a refrigerant is conveyed into an evaporator by a strong solution from which it evaporates into the inert gas to produce the cooling effect after which the solution is then conveyed to a boiler where it is further weakened by the application of heat, so that it may subsequently absorb the refrigerant expelled in the evaporator out of the inert gas. The refrigerant expelled in the boiler is then conveyed to a second absorber which contains no inert gas, where, it is then absorbed and returned by the strong solution 'to the evaporator. In other words, a single absorption liquid is circulated through a system of vessels consisting essentially of an evaporator, a boiler and two absorbers which are inter-connected. The thermodynamic environment in the vessels is varied-by circulating an inert gas through the evaporator and one absorber and by the application of heat .to the boiler, and removal of heat from the absorbers so that refrigeration is effected in the evaporator. J A further object is to provide a continuous absorption refrigerating system adapted to operate will be'apparent from the following description to be understood that the invention is not limited without moving parts and in whichall of the parts are hermetically sealed together.

Another object of the invention is to provide a continuous absorption refrigerating system in which the pressure at which the unit operates-m may be relatively low, for example not more than one or two atmospheres, although the invention isnot limited to operation at such pressure.

Other objects and advantages of the invention taken in connection with the accompanying drawings in which Fig. 1 is a more or less diagrammatic showing of a system of inter-connected vessels, illustrating a system adapted to carry out certain of the principles of the invention.

Fig. 2 is a diagrammatic showing of another embodiment of the invention in which no moving parts are employed.

Fig.,3 illustrates an apparatus in which various mechanical expedients, now well known in the art, have been added to improve the operation of systems such as those shown in Figs. 1 and 2.

Fig. 4 is an illustration of a different form of practical--working apparatus somewhat similar to that of Fig. 3, but in which the parts are somewhat difierently arranged.

Fig. 1 illustrates the basic principle involved in this invention. As there shown the apparatus consists of an evaporator E, a boiler or generator in the form of a coil as shown at B, a gas separating chamber S, two absorbers designated A1 and A2, two heat exchangers, one for the solution designated by the reference character 10 and one I for the gas designated by the numeral, 11. A fan or blower for circulating the gases in heat exchanger 11 is shown as 12. These various devices may be of any suitable well-known construction and are connected together by pipes as shown.

The evaporator E may be provided with a coil as shown at'l3 for conducting heat from a device to be cooled to the evaporator by circulating brine or the like therethrough. It is, of course,

to this indirect manner of cooling, but the evaporator may be placed in a refrigerator cabinet or the like so as to cool it directly.

The boiler 13 is in the form of a small coil of pipe which may be heated by an electric cartridge heater such as is shown at 14,- or by a gas flame or other suitable source of heat. This coil not only acts to expel gas from the solution therein but also acts as a pump. For a full disclosure of this device reference may be had to and A2 may be provided with coils such as are shown at or 16 for conveying heat away therefrom by circulating cooling water through them. Obviously other forms of water cooled absorbers may be used such as those in which the water is circulated through a jacket around the body of the absorber or if desired the absorbers may be air-cooled in which case suitable heat radiating fins should be placed upon them.

As shown, the separator may be an ordinary vessel. In addition to the heat supplied to aim boiler B, heat may also be supplied to separator S by a gas flame or the like if desired.

,duit of the heat exchanger 11.

The heat exchangers may be of any conven-- tional type. As shown they are made up of two concentrically disposed pipes so that the heat may readily be conveyed from the fluid in one to the fluid in the other.

The fan 12 may be of any suitable construction and driven by an electric motor or the like.

The apparatus operates as follows:--

Assuming a quantity of aqua-ammonia of a concentration, say of between 20 and 40% has been placed in the apparatus through suitable valves not shown until it has filled the heat exchanger and the lower half of the evaporator E,

exchanger 11 into the absorber A1 and back to the evaporator through the fan 12 and inner con- Circulation of the absorption solution will also begin because of the formation of bubbles in the boiler B. The

solution circulation is as follows:

From the evaporator E through the conduit 18, boiler B, gas separating chamber-S, conduit 19,

absorber A1, conduit 20, outer conduit of heat from the liquid in the separating chamber S it passes through the conduit 24 into the absorber A2. The solution thus weakened is conveyed from the separator through the conduit 19 into the absorber A1 where it comes in contact with theinert gas such as air (or hydrogen) which is laden with ammonia gas from the evaporator and at the temperature prevailing in the absorber A1 the weak solution picks up or absorbs the ammonia out of the inert gas. It is of course, obvious that if refrigeration is to be produced, evaporation of refrigerant in the evaporator E must take place at-a lower temperature than that at which it is absorbed in the absorber A1. It is therefore necessary that the solution conveyed to the absorber be considerably weaker than that in the evaporator since the total pressure in the two is the same. Thus the function of the boiler B is to weaken the solution to enable it to pick up ammonia in the absorber A1. The solution strengthened in A1 is conveyed through the conduit 20, outer conduit of the heat exchanger 10 and conduit 22 into the absorber A2. Now in the absorber A2 as well as in the separator S, conduit 24 and boiler B, there is no inert gas. Thus in the evaporator and in the absorber A1 the ammonia partial pressure is less than the total pressure in the machine by the amount of 1,953,993 Altenkirch Patent 1,728,742. Both absorber A1:

the inert gas partial'pressure therein, while the ammonia vapor pressure in the boiler and ab- I sorber A2 is approximately equal to the total pressure in the machine. Under these conditions the solution entering absorber A2, may pick up an additional amount of ammonia gas this being conveyed from the boiler through the conduit 24. This solution, which is the strongest of any in the apparatus, is then conveyed to the evaporator through the conduit 23 and evaporation again takes place into the inert gas as recited above.

It will thus be apparent. that the solution, in passing through a complete cycle is subjected to a process in which: (1) The refrigerant, as ammonia is evaporated into the inert gas as air to produce a cooling effect in the evaporator where the partial pressure of the refrigerant is low.

(2) Refrigerant is evaporated in the boiler by the application of heat without inert gas being present so that the partial pressure of the refrigerant is high.

(3) Refrigerant is absorbed from the inert gas in the absorber A1 where the partial pressure of the refrigerant is low and (4') Refrigerant is absorbed in the absorber A2 where the partial pressure of the refrigerant is high.

It will also be seen that there is only one solution cycle in the apparatus and that the refrigerant evaporates inthe evaporator from the solution rather than from a nearly pure liquid state as contemplated in most absorption refrigerating apparatuses. The absorber A2 is in some respects similar to the condenser of the conven tional inert gas absorption machine, such as shown by Geppert but since it is not necessary to condense the refrigerant but only to absorb it into a solution the apparatus may operate under a total pressure lower than that suggested by Geppert.

The apparatus of Fig.v 1 is only intended to illustrate the principle involved and does not employ eflicient means for bringing the liquid and gases into intimate contact to effect proper evaporation and absorption although such expedients are contemplated as will be evident after consideration of Figs. 3 and 4 hereinafter described.

Referring now to Fig. 2, the diagram illustrates a unit like that of Fig. 1 except for the means employed for circulating the fluids. The evaporator E, absorber A, boiler B and separator S may be of the same construction as described in connection with the arrangement of Fig. 1 although their relative positions are not the same.

A jet or nozzle 25, in cooperation with a suitable venturi 26, causes the circulation of the inert gas through the pipes 2'7 connecting the evaporator E and absorber A. The jet is supplied with a portion of the refrigerant gas driven out of the solution in the boiler B and separator S.

The separator being located below the absorber gravity cannot be used in causing the sofluid then flowing into the evaporator, this column of fluid also being under the influence of the pressure generated in the separator S and boiler B. The absorber A2 being in the form of a smallcoil, it also functions as a gas lift pump.

In the diagram of Fig. 2 no heat exchangers are shown but their use is obvious in view of the showing in Fig. l. I

In Fig. 3 a machine is illustrated in which well known types of baffled evaporators and absorbers are employed and in which various other devices such as a rectifier, a receiver, and a vent pipe for conveying gases away from the absorber A2 are employed for improving the operation of ap paratus like that shown inFigures l and 2. In Fig. 3 the parts corresponding to those of Fig. 1 are similarly designated, these being the evaporator E, the boiler B, separator S and absorbers A1 and A2.

As shown in Fig. 3 the evaporator E and absorber A1 consist of vertically disposed cylindrical vessels provided on their inside with a series of plates or bafiies. These plates may be made of sheet metal disks with segments cut away and may be slightly cupped if desired. In assembling, the cut away portions are staggered to cause fluids flowing thru the vessels to travel over a tortuous path. The absorber A2 of this figure is shown as made up of two concentric coiled pipes, the outer pipe serving merely as a jacket thru which water may circulate to cool the fluids in the inner pipe. The boiler B is of a known construction and consists of a cylindrical drum 30 having a tube 31 extending horizontally therethrough for receiving an electric cartridge heater 32. The pipe 33 is of small diameter and cooperates with the maindrum 30 of the boiler to obtain a pumping action similar to that of v the boiler B in Fig. l, the liquid being carried upward therein by the lifting action of gas or vapor which form therein. The separator is an ordinary vessel provided with two outlets as shown, one at the bottom and one near the upper 'portion thereof. It may be provided with a heater if desired. I

In addition to the elements mentioned above the system of Fig. 3 is also provided with a vertically extending cylinder35 which acts as .a reservoir and a rectifier, the upper portion being provided with a series of battles 36 for this purpose. The refrigerant vapor enters the cylinder 35 below the baffle plates through the conduit 3'7 and as it passes upwardly over them to the conduit 38, the water vapor entrained with it is condensed. The water collects in the bottom of the cylinder 35 and is conveyed back into the drum 30 of the boiler thru the conduit 39. The lower end of the cylinder 35 may be provided with a tube 40 held in place by a plate 411 opposite the conduit 39 to prevent surges, oc-

casioned by sudden expulsion of vapor from the solution in the boiler, from adversely affecting the operation of the system.

Theupper portion of the conduit 38 which conveys vapor away from the cylinder 35 may be inclined slightly from the horizontal as shown and provided with radiating fins 43 to provide additional rectification. This pipe then extends downwardly and is joined to one leg of a U-shaped pipe 44 which conveys absorption liquid out of the absorber A1 into the absorber A2, this union being a suitable distance below the absorbers. The left hand leg of the U-shaped pipe 44 being of small diameter, a pumping or lifting action is obtained by mixing gas from the conduit 38 with This action is pipe from a point without. As the refrigerant gas and absorption liquid rise through the conduit 44 they are of course in intimate contact and some absorption takes place. As the solution passes thru the coils of absorber A2 more refrigerant is absorbed and carried away with the solution thru the conduit 45. Should any of the refrigerant gas not be absorbed or should any of the inert gas become entrained in the absorption liquid and carried into the absorber A2, as sometimes happens in devices of this nature, it will collect in the small vessel to shown at the left hand side of the absorber A2 and be conveyed thru the conduit 47 back into the absorber A1 after passing thru a device called a swallower 48. This swallower functions merely to maintain a liquid seal for preventing the passing ofgases from the absorber A1 to the chamber 46. In making up'the swallower, a pipe 49 which may be concentrically disposed with respect to the right hand leg of the U-pipe 44, as shown, is connected to the'lower end of the absorber A1 and has an auxiliary conduit 15 arranged alongside thereof which is connected to it at the bottom and connected to the lower end of the absorber A1 at the top. These two pipes being filled with liquid, as absorption solution, when gas from the vessel id is fed into the auxiliary pipe 15 thru the pipe 47, the liquid in the swallower rises thru the conduit 50 and flows downwardly thru the conduit 49 while at the same time maintaining an adequate seal and preventing surges or fluctuations, caused by changes in pressure which might otherwiseoccur.

Absorption liquid conveyed by the pipe 45 out of the absorber A2 is fed into the lower end of a conventional heat exchanger 52 and conveyed thru the outer conduit thereof and the pipe 53 to the upper end of the evaporator. For conveying the absorption liquid from the evaporator back to the boiler, the conduit 54 connects the evaporator to the inner coil of heat exchanger 55 which is in turn connected to the lower end of the reservoir cylinder 35. The pipe 56 conveys absorption liquid from the separator S thru the outer conduit of the heat exchanger 55 to the absorber A1 thru the conduit 57. To prevent an accumulation of an excess of absorption liquid in the absorber A1 an overflow pipe 58 connects it to the conduit 54 so that the excess may drain back into the boiler. shown in Fig. 1 means is provided for circulating an inert gas such as air or hydrogen between the evaporator and absorber A1. For this

purpose conduits

60 and 61 are disposed between these vessels, portions of the two being in heat exchange relation as shown at 62. In place of the fan 12 of Fig. 1, a jet is used for obtaining circulation of the gases. A portion of the conduit 61 is restricted as shown at 63 to provide a suitable venturi thru which the gases are forced by a nozzle 64 fed by refrigerant gases from the separator by the conduit 65. The portion of the refrigerant gas fed to the nozzle produces no useful cooling effect but since this is only a small'portion of that expelled from the solution in the boiler, this loss is not of great consequence.

This apparatus is charged and operated as follows:

A. quantity of suitable refrigerant such as ammonia together with a. solvent such as water is placed in the apparatus thru suitable valves, not shown, until it has filled the lower portion of the apparatus and has risen to a level slightly below the point where the conduit 37 is connected to the reservoir 35. There being some air collected in the upper part of the machine, it will probably not be necessary to add any more but should it be necessary, air under pressure may be fed into the evaporator or absorber A1 from a suitable source to raise the pressure above atmospheric before application of heat to the boiler. Obviously hydrogen or other inert gas may be used instead of air. If desired, the entire system may be swept out with ammonia gas in the usual manner before the inert gas is supplied. After the charging valves are closed, heat may be supplied to the boiler and cooling water run to the absorber A2. In this connection it should also be observed that either or both absorbers may be air or water cooled. In the construction shown the absorber A1 is air cooled and the absorber m is water cooled.

As heat is supplied to the drum 30 of the boiler the solution rises thru the conduit 33 because of the formation of gas bubbles therein and is conveyed to the separator S where the refrigerant gas leaves the solution thru the conduit 37. The weakened solution passes downwardly thru the conduit 56, outer coil of heat exchanger 55, conduit 57 into the upper end of absorber A1. After trickling down over the plates in the absorber A1 the solution which has been enriched in this absorber by absorbing refrigerant from the inert gas therein passes thru the conduit 54 and is lifted into the absorber A2 after mixing with re-' frigerant gas conveyed thru the conduit 38 into the conduit 44.- More refrigerant being absorbed in the absorber A2, this'enriched solution passes thru the conduit 45, outer pipe of heat exchanger 52, pipe 53 into theupper end of the evaporator. As it' trickles down over the baffle plate in the evaporator, the refrigerant evaporates out of this rich'solution into the inert gas. The solution thus weakened passes downwardly thru the inner pipe of heat exchanger 52, conduit 54, inner pipe of heat exchanger 55, lower portion of reservoir 35 and conduit 39 back to the boiler thus completingits cycle. The refrigerant expelled in the boiler after passing thru the conduit 37 rises thru the rectifier plates 36 in the upper end of the reservoir cylinder 35 and passes thru the conduits 38 and 44 into the absorber A2.

The refrigerant gas which has evaporated from the solution in the evaporator to produce a cooling effect is carried by the inert gas thru the conduit 61 into the absorber A2 .where it is absorbed again as explained above, the weakened inert gas being returned to the evaporator thru the conduit 60.

It will thus be seen that this system operates fundamentally the samelas that illustrated in Fig; 1'. Since, however, the absorber A2 is located above the absorber A1 it is necessary that the solution be lifted twice, 'once inthe conduit 33 and once in the conduit 44. The ratio of the lifting height to the height of the liquid in the reservoir '35 and the point at which the conduit 38 is connected to the conduit 44 are thus important factors in a proper design of this apparatus.

These and other factors encountered in the use. 'of gas lift pumps are now well known to those skilled in the art being discussed among others in a publication entitled, Uber Messungen an kleinen Mammutpumpen (Measurements of Small Air-Lift Pumps) by Dr. K. Nesselmann, Vol. IV, No. 1, 1927, of Wissenschaftliche Veroffentlichungen aus dem Siemens-Konzern, this being a publication of the Siemens-Schuckertwerke, Berlin-Siemensstadt, Germany. It will be noted that in the unit shown in Figure 3, like the one shown in Figure 2, the pressure in the gas separating chamber S is higher than that in the absorber A2 and that this excess of pressure is utilized to force solution into the absorber A2, since it cannot be conveyed by gravity from the lower end of absorber A1 into the absorber A2 at a higher level. Figure 4 illustrates an apparatus in which the solution may flow by gravity from the separator S into the absorber A1, from there into the absorber A2 and from there into the evaporator E without the interposition of any gas lift pump being necessary. Because of its similarity to that of Figure 3, a full description of this figure will not be necessary except insofar as the operation of the absorber A2 is concerned and the -manner in which the fluids are circulated. v

The absorber A2 consists merely of a pipe 70 with an outlet pipe 71 extending through the end closure 72 at the lower end and up to a point slightly below the lower end of the absorber A2.

This unit being charged and heat applied to the boiler, the path of travel of the solution may be traced as follows:

Starting with the boiler B, the solution is lifted by the formation of refrigerant gas bubbles in the pipe 73 into the separator S from which it flows downwardly through the conduit 74, outer p'pe of heat exchanger 75, upwardly through pipe 76 into the top of the absorber A1, through the absorber A1 and U pipe 77 into the lower end of absorber A2 where as it rises, it mixes with and absorbs the'gas entering the absorber A2 from the separator S through the conduit 78. The solution then passes downwardly through the conduit 71 into the outer pipe of heat exchanger 79 through the heat exchanger and pipe 80- into the top of evaporator E and back to the boiler through the conduit 81, inner pipe of heat exchanger 79, conduit 82, inner pipe of heat exchanger 75 and conduit 83.

An inert gas circuit is provided between the evaporator and the absorber A1 by means of the pipes 84 and 85, portions of which are in heat exchange relation, as shown at 86. A jet 8'7, similar to that described in connection with the structure of Fig. 3 is supplied with a portion of the refrigerant gas expelled in the separator through the conduit 88.

The upper end of absorber A takes the place of the small vessel 46 of Fig. 3 and provides means for the collection of any gases which have not been absorbed in the absorber A2. These gases are carried away through the conduit 89 into a swallower 90 which is of a slightly different construction than that of Fig. 3. As shown it consists of two pipes arranged concentrically with a portion of the U-pipe 77 and secured to the lower end of the absorber A1. The upper and lower edge of the inner pipe 91 of this swallower are provided with openings or holes such as shown at 92 so that the liquid which maintains a seal in the swallower may flow upwardly between the inner and outer pipes upon gas entering the pipe 89 and then flow downwardly between the inner pipe of the swallower and the portion of the conduit 77 which is inside thereof. A perforated cap 93. may be secured to the upper end of the I can be made without departing from the spirit of the invention or the scope of-the annexed claims.

I claimz- 1, In an absorption refrigerating system the combination with an evaporator and an absorber of means for circulating an inert gas between and thru said evaporator and said absorber and for maintaining substantially the same pressure therein, means for circulating a solution consisting of a refrigerant and a solvent therefor between and thru said evaporator and said absorber, and means for removing refrigerant from the solution as it passes from the evaporator to the absorber and for replacing it inthe solution as it passes from the absorber to the evaporator, to thereby cause the average concentration of the solution in the absorber to be maintained lower than the average concentration of the solution in the evaporator and permit the refrigerant to evaporate from the solution in the evaporator into the inert gas therein to produce a cooling effect and be absorbed out of the inert gas by the solution in the absorber at a higher temperature than that prevailing in the evaporator.

2. In an absorption refrigerating system an evaporator, an absorber, means connecting the evaporator and absorber for holding inert gas therein, means for conveying a solution of refrigerant thru the evaporator and absorber, means for causing the refrigerant to evaporate in the evaporator into the inert gas and means for causing the solution to absorb the refrigerant out of the inert gas in the absorber and return it to the evaporator.

3. In an absorption refrigerating system, the combination with an evaporator and an absorber of means for circulating an absorption solution between them, and means for removing refrig erant from the solution as it passes from the evaporator to the absorber and for replacing the refrigerant in the solution as it passes from the absorber to the evaporator.

4. In .an absorption refrigerating system, the combination with an absorber of means for circulating an absorption solution therethrough and means for removing refrigerant from the solution as it passes to the absorber and for replacing the refrigerant in the solution as it is conveyed away from the absorber to thereby increase the ability of the solution to absorb refrigerant in the absorber.

5. In absorption refrigerating apparatus the combination with an evaporator and an absorber of conduit means for conveying an absorption solution between them, means for removing refrigerant from the solution as it passes from the evaporator to the absorber, and means for replacing the refrigerant in the solution, as it passes from theabsorber to the evaporator, said last mentioned means including a pipe of small diameter adapted to function as a gas lift pump and cause circulation of the solution.

6. In absorption refrigerating apparatus, the combination with an. evaporator and an absorber of conduit means for conveying an absorption solution between them, means including a gas lift pump for causing circulation of the solution thru said conduit means for removing refrigerant from the solution as it passes from the evaporator to the absorber and means for replacing the refrigerant in the solution as it passes from the absorber to the evaporator.

57. The method of producing refrigeration which includes the steps of causing a refrigerant to evaporate from a solution thereof into an inert gas in an evaporator, conveying the gas laden with refrigerant vapor to an absorber, also conveying the solution from the evaporator to the absorber and changing the concentration of the solution as it passes from the evaporator to the absorber to enable it to absorb the refrigerant vapor from the inert gas at the same pressure but a higher temperature than that prevailing in the evaporator.

8. The method of producing refrigeration which includes the steps of circulating a solution of refrigerant thru'an evaporator and an absorber, removing refrigerant from the solution as it passes from the evaporator to the absorber and replacing the refrigerant in the solution as it' passes from the absorber to the evaporator.

9. The method of producing continuous refrigeration by causing a solution of refrigerant to pass thru a cycle, the steps of which consist of evaporating a refrigerant out of a solution to produce a cooling effect, heating the solution to weaken it further by expelling more refrigerant therefrom, causing the refrigerant first evaporated to be absorbed in the weakened solution and then causing the refrigerant expelled during the second mentioned step to be absorbed in the solution.

' 10. In a refrigerating system, an evaporator, an absorber, means for circulating a refrigerant gas between them, means for circulating a refrigerantliquor between the evaporator and the ab:-

sorber and means for diverting a portion of the refrigerant contingent of said liquor from circulation with the liquor through said absorber.

11. In a refrigerating system, an evaporator, an absorben'means for establishing a refrigerant gas circuit between them, means for circulating a refrigerant liquor between the evaporator and the absorber, a separator in said liquor circulating means operableto separate from the liquor at least a part of the refrigerant contingent thereof, means for conveying the weakened liquor to the absorber andmeans for returning the separated refrigerant contingent to the evaporator.

12. In a refrigerating system, an evaporator,

an absorber, means for establishing a refrigerant gascircuit between the evaporator and the absorber, a separator in one of said conduits and operable to separate from the liquor at least a part of the refrigerant contingent thereof, a second absorberin the other of said conduits and means for conveying the refrigerant separated in said separator directly to said second absorber 14. In a refrigerant system, two vessels located at points relatively spaced from each other, means for circulating refrigerant liquor between .said vessels and meansfor by-passing at least a portion of the refrigerant contingent of the liquor around one of said vessels.

15. In a refrigerating system, an evaporator,

an absorber, means for establishing a refrigerant gas circuit between the same, conduits for circulating a refrigerant liquor between the evaporator and the absorber, a generator operable for vaporizing or gasifying at least a portion of the refrigerant contingent of the liquor while it is passing through one of said conduits, a second absorber associated with the other of said conduits, means for dividing said vaporized or gasified refrigerant portion, means for conducting one portion thereof into said second absorber for absorption by the refrigerant liquor passing therethrough and means for conducting the other portion into the channel of said refrigerant gas circuit for effecting a circulation thereof.

16. In a refrigerating system, two vessels located at points spaced from each other, conduits for circulating refrigerant liquor between said vessels and means for by-passing a portion of the refrigerant contingent of the liquor around one of said vessels, said means including a generator located in one of said conduits and an absorber in another of said conduits.

17. Ina refrigerating system, two vessels located at points spaced from each other, conduits for circulating refrigerant liquor between said vessels and means for by-passing a portion of the refrigerant contingent of the liquor around one of said vessels, said means including a gas lift pump located in one of said conduits and an absorber in another of said conduits.

18. In a refrigerating system, an evaporator, an absorber, conduits for circulating a refrigerant liquor between the same, a generator operable to vaporize a portion of the refrigerant contingent of the liquor as it passes from the evaporator to the absorber, a second absorber associated with a conduit which conveys the liquor from the first mentioned absorber to the evaporator and operable to cause the portion of the refrigerant vaporized by the generator to be returned to the 19. In a refrigerating system, an evaporator,

an absorber, conduits for circulating a refrigerant liquor between the same, a generator operable to vaporize a portion of the refrigerant contingent of the liquor as it passes from the evaporator to the absorber and also operable to cause circulation of the refrigerant liquor due to the vaporization of refrigerant therein, a second absorber associated with a conduit which conveys the liquor from the first mentioned absorber to the evaporator and operable to cause the portion of the refrigerant vaporized by said generator to be returned to the liquor in the conduit with which it is associated, whereby the portion of the refrigerant vaporized in said generator is lay-passed around said absorber.

20. In a refrigerating system, an evaporator, an absorber, conduits for circulating a liquid between the same and a generator located in one of said conduits for expelling a, vapor from said liquid.

21. In a refrigerating system, an evaporator, an absorber, conduits for circulating a liquid between the same and a generator located in one of said conduits for expelling a vapor from said liquid, said generator being so designed as to cause 105 circulation of said liquid due to the expulsion of said vapor.

22. Refrigerating apparatus comprising a boiler, an absorber, an evaporator, a second absorber, and means to cause liquid to be thermosiphoni- 11g; cally circulated from the boiler to the second absorber, from the second absorber to the first named absorber, from the first named absorber to the evaporator, and from the evaporator back to the boiler.

til

DONALD G. SMELLIE.