US2295988A - Refrigeration - Google Patents

Description

Sept. 15, 1942. AE 9 2,295,988

REFRIGERATION Filed April '24, 1939 5 Sheets-Sheet 1 III YINVENTOR G'eqrye A. Brace ATTORNEY Se t. 15, 1942. v, G, A, BRAC; 2,295,988

REFRIGERATION Filed April 24, 1959 5 Shets-Sheet 2 INVENTOR Gozye A. Brace ATTORNEY Sept. 15, 1942. G. A. BRACE 2,295,988

' REFRIGERATION Filed April 24, 1939 5 Sheets-Sheet 5 INVENTOR F93 George A. Brace ATTORNEY Sept. '15, 1942.

G. A. BRACE REFRIGERATlQN Filed April 24, 1939 5 sheets sheet 4 11 11.[ m li| 4 lNVENTOR Ge urge A. firace ATTO RN EY Spt. 15,1942. RACE" 2,295,988

REFRIGERATION Filed April 24, 1939 5 Sheets- Sheet 5 u L I! v I II INVENTOR F 7 K I George .A-BIQCG ATTORNEY patented Sept. 15, 1942 REFRIGERATION George A. Brace, Winnetka, 111., assignor to The Hoover Company, poration of Ohio North Canton, Ohio, a cor- Application April 24, 1939, Serial No. 269,613

32 Claims.

M This application relates to the art of refrigeration and more particularly to a novel absorption refrigerating system.

tion to provide an absorption refrigerating. system of the air-cooled'type in which the absorber The present application contains subject matter divided from my co-pending application, Serial No. 248,671, filed December 31, 1938. The present invention also relates to certain improvements over my co-pending application Serial No. 220,196, filed July 20, 1938. The said copending application discloses an absorption refrigerating system of the type utilizing an inert pressure equalizing medium in which all fluids are positively circulated through their respective circuits by a small mechanical circulator for the pressure equalizing medium. The liquid refrig-,

erantsupplied to the evaporator is propelled upwardly therethrough as it is evaporating into the pressure equalizing medium by the sweeping or dragging action exertedon the liquid refrigerant by a relatively high velocity stream of the pressure equalizing medium. The absorption solution is elevated from the level of the boiler to a higher elevation in an absorber vessel through which it is propelled by the sweeping or dragging action exerted thereon by a relatively high velocity stream, of pressure equalizing medium. The absorption solution then flows by gravity in its path of flow back to the boiler through another absorber element. I

My co-pending application Serial No. 248,671 discloses an absorption refrigerating system providing a novel means for regulating the flowof the fluids therethrough under all normal conditions of operation.

The present application is directed to certain improvements over the refrigerating system disclosed in my said two co-pending applications and also to novel arrangements of the various forms of apparatus within a domestic refrigerating cabinet in order to achieve the highest usefulness of the above-mentioned refrigerating system.

It is a further object of the present invention to provide an absorption refrigerating system including a tubular air-cooled absorber having a portion thereof positioned partly beneath the storage compartment in a horizontal or an inclined position and having another portion thereof in the rear air-cooling flue.

It is afurther object of the invention to provide an absorption refrigerating system in which the absorber is of the type in which the absorption solution is circulated therethrough by the inert gas and is provided with a plurality of sections, parts of which are positioned in the rear air-cooling flue and other parts of which are positioned at least partially in the mechanism compartment beneath the insulated food storage includes a combined elevating, absorbing and heat rejecting element which extends across the rear portion of the cabinet in a series of short steps each of which is providedwith air-cooling fins.

It is another object of the present invention to provide an absorption refrigerating system of the type in which the absorber consists of a plurality of finned sinuous vertically positioned sections, all of which are positioned entirely within the rear portion of the air-cooling flue.

Heretofore, absorption refrigerating systems of the type above referred to have been arranged in a cabinet construction with the mechanism distributed in a lower mechanism compartment and a vertically extending cooling air flue. This arrangement was very wasteful of space and practically prevented the provision of a storage chamber in the cabinet beneath the refrigerated food storage compartment. Additionally, with prior arrangements, it was necessary to construct the lower mechanism compartment at a relatively great height which resulted in an expensive cabinet construction and an appreciable wastage in space.

Accordingly, it is an object of the present invention to provide an absorption refrigerating system in which the mechanism is distributed in a compact efficient manner in a rear air cooling flue and in the extreme rear portion of the lower compartment whereby a storage compartment of substantial size may be formed in the cabinet beneath the refrigerated food storage compartment.

' It is still another object of the present invention to provide a three-fluid absorption refrigerating system in which a most efilcient and compact arrangement of the apparatus in a cabinet is provided.

More specifically it is an object of the present invention to providea refrigerating apparatus in which the absorber is horizontal and has the major portion thereof; located below the analyzer which may be higher than the mechanism compartment customarily provided beneath the food storage chamber.

In prior constructions it has been absolutely essential to incline all portions of the absorber present invention to provide an absorption refrigeration system in which all or part of the absorber may be positioned horizontally without suffering adversely from any tilt which the apparatus may have.

It is another object of the present invention to provide an absorber in which the solution is propelled by the inert gas over an obstruction in a manner to project the liquid as a spray and to cause the gas and liquid to scour across the interior walls of the absorber.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings, in which:

Figure 1 is a side elevational view, partly in section, of a refrigerator cabinet construction embodying the present invention.

Figure 2 is a diagrammatic representation of the absorption refrigerating system illustrated in Figure 1 in connection with a cabinet.

Figure 3 is a side elevational view, partly in section, of a modified form of the invention.

Figures 4 and 5 are enlarged detail sectional views of an absorber construction.

Figure 6 is a cross-sectional view taken substantially on the line 66 of Figure 5.

Figure 7 is also a side elevational view, partly in section, of a still further modification of the invention.

Referring now to the drawings in detail and first to Figures 1 and 2 thereof, there is disclosed an absorption refrigerating system of the threeiluid type comprising a boiler B, an analyzer D, an air-cooled rectifier R, a tubular air-cooled inclined condenser C, an evaporator E, a gas heat exchanger G, a liquid heat exchanger L, a pair of tubular air-cooled absorber vessels A and A, a solution reservoir S, and a circulating fan F which is driven by a suitable electrical motor M which is hermetically sealed into the system. The above described elements are suitably con- .nected by a plurality of conduits forming a plurality of gas and liquid circuits constituting a complete refrigerating system to which reference will be made in more detail hereinafter.

The above described system is charged with a suitable refrigerant, such as ammonia, a suitable absorbent, such as water, and a pressure equalizing medium preferably a dense inert gas, such as nitrogen.

The boiler B may be heatedin any suitable manner as by an electrical cartridge heater or by a combustible fuel burner. In the instant case a gas burner H is illustrated.

Referring now to Figure 2, the refrigerating system-per se will be described. The application of heat to the boiler B generates refrigerant vapor from the strong solution therein contained. The vapors, so generated pass upwardly through the analyzer D in counterflow relationship to strong solution flowing downwardly therethrough,

whereby further refrigerant vapor is generated from the strong solution by the heat of condensation of absorption solution vapor liberated in the boiler. The resulting refrigerant vapor is conveyed from the analyzer D to the top portion of the condenser C by a conduit I I which includes the air-cooled rectifier R wherein absorption solution vapor which passes through the analyzer is condensed. The refrigerant vapor is condensed in the condenser C by heat exchange with ambient air and is discharged through a conduit l2 including a U-shaped liquid seal portion into the denser is vented by a conduit l3 to the rich gas side of the gas heat exchanger.

The evaporator E may be of any suitable or desired construction, a preferred construction being illustrated in the co-pending application of Curtis C. Coons and William H. Kitto, Serial No. 386,395, filed April 2, 1941. The bottom portion of the evaporator is supplied with lean pressure equalizing medium which discharges from the circulating fan F through the conduit I4, the outer path of the gas heat exchanger G, and the conduit l5 which opens into the bottom portion of the evaporator E. The evaporator E is constructed of relatively small diameter tubing, as will be explained in more detail hereinafter, wherefore the inert gas flows therethrough at a relatively high velocity which is sufficient to sweep or drag the liquid refrigerant through all portions thereof as it is evaporating into the inert gas stream to produce refrigeration. The rich mixture of pressure equalizing medium and refrigerant vapor formed in the evaporator E and in the box-cooling conduit. [6 thereof is conveyed from the box-cooling conduit l6 through a conduit I! to the inner path of the gas heat exchanger G from which it is conveyed by a conduit l8 to the lower portion of the absorber A.

The .weak solution formed in the boiler B by the generation of refrigerant vapor therefrom is conveyed from the boiler by a conduit 20, the outer path of the liquid heat exchanger L, and a conduit 2! into an upstanding chamber 22 which communicates with'the bottom portion 24 of the absorber A. The bottom portion 24 of the absorber A comprises a plurality of sinuous serially connected individually finned inclined conduits, as will be apparent from the inspection of Figuresl and 2. The individual absorber tubes are parallel and are not alternately oppositely inclined as is essential in the gravity flow type of apparatus. The bottom portion of the absorber A is at an elevation slightly above the liquid level prevailing in the boiler-analyzer system B-D. In order to elevate the lean solution to the bottom portion 24 of the absorber A, a small gas bleed-off conduit 23 is connected between the circulating fan discharge conduit l4 and the elevating conduit 2| below the liquid level prevailing therein whereby the weak solution is elevated into the bottom portion 24 of the absorber A by gas lift action.

The bottom portion of the absorber A is connected to finned air-cooled discharge conduit 28 of the absorber A by means of a conduit 25. A small dip is formed in the conduit 25 just ahead of its point of connection with the vessel 22 which is drained by means of a conduit 21 into the lean solution elevating conduit 2 I. This conduit takes care of any solution finding its way into the conduit 25 [from the absorber A and also drains any solution which may flow counter to the inert stream in the absorber A. v

The upper portion 10 of the absorber A consists of a series of horizontal off-set vertically spaced short finned conduits 3| which are serially I connected by short riser conduits 32.

bottom portion of the evaporator E. The con- The absorber A, like the evaporator E, is constructed of a relatively small diameter tubing. and is connected in circuit in a manner which will be described hereinafter in order to permit the inert gas to flow upwardly therethrough at a relatively high velocity. The inert gas propels the absorption solution supplied to the bottom portion of the absorber A from the vessel 22 upwardly through A as it is absorbing aromas the refrigerant-vapor content of the inert gas and is rejecting the heat of absorption to cooling air flowing over the fins mounted thereon. l

, ,The absorption solution and inert gas which have traveled upwardly through the absorber A discharge-into a separating chamber it which is connected to the suction inlet of the circulating the inert gas and absorption solution have travdownwardly through theabsorber A in'counterflow to the rich mixture pressure equalizing medium flowing upwardly therethrough from. the

operation of the system as a whole.

The absorber A is made of relatively small diameter tubing whereby the inert gas travels therethrough at a velocity sufilcient to sweep or drag the liquid refrigerant from the bottom to the top portion of the absorber as it is absorbing refrigerant vapor and is rejecting the heat of absorption to coolingeair through the medium of the fins mounted on the absorber tubes. After ersed the absorber A, the lean inert gas is discharged into the suction inlet of the circulating fan and the somewhat enriched absorption solution is conveyed through the conduit 29 to the absorber A.

The absorber A is made of large diameter tubing and, as will be apparent from the description above of the inert gas circuit, the gas and liquid rich gas conduit ll. The heat of absorption is rejected toair flowing over the outer walls of the abmrber vessel and the strong solution formed therein is discharged through a conduit 33 into the solution reservoir 8. The absorber A as a whole lies in a substantially vertical plane but the individual selgally connected tubes thereof are preferably alternately oppositely inclined to the horizontal to provide for gravity flow of the solution.

" A The absorbers may be constructed from a con tinuous tube bent into the desired shape or from a plurality of preformed sections which are suitably ioined together as by welding or brazing.

Each absorber tube element is preferably provided with individual fins ll. As illustrated the fins are offset from the tube in the direction of theair flow. Thisarrangement produces most efllcient heat rejection to the air stream with a minimum fin area and a minimum of air flow resistance. i

The solution reservoir 8 is vented by means of i .a small conduit :4 to the suction inlet or the circulating fan F. The strong solution in. the reservoir is returned to the analyzer D by way of the conduit II, the inner path of the liquldheat exchanger L, and a conduit 38; The drain conduit II for the evaporator also connects to the strong solution return conduit 35.

The operation of the apparatus is regulated by a control II which may be of any desired type, though a preferred construction is disclosed and claimed in the co-pending application of Curtis C. Coons, Serial No. 148,424, flied June 16, 1937, 1 Patent No. 2,228,343. Gas is supplied to the bumer H through a conduit 3! which passes through the regulating mechanism 38. Electrical energy is supplied to the circulating motor M by means of electrical conductors 40 which also pass through and are controlled by the mechanism 38.

Theoperation'of the system, insofar as it has not been described above, is as follows: The gas lift pump which serves to supply the lean absorption solution to the bottom portion of the absorber A' provides a'means whereby therate at which solution is supplied to the absorber is substantially constant and is independent of flow therethrough in counter-flow relationship. This is made'possible by the fact that the large diameter tubing of which. the absorber A is constructed causes the gas to flow therethrough at a relatively low velocity whereby it does not propel the absorption solution which flows through the absorber A solely by gravity.

With the arrangement illustrated the absorber A carries the burden of the absorbing load and will operate at a relatively high temperature.

After the solution has traversed the absorber A it has reached its highest refrigerant concentration and is consequently returned to the analyzer. The inert gas refrigerant vapor mixture,

however, is then cooled in the conduit 25 and returned to the inlet of the absorber A y means of the conduit 25 at which point the relatively lean inert gas is brought into intimate contact 5, with the leanest absorption solution to be found in the system. Theabsorber A, therefore, acts as a stripping absorber for the inert gas and will operate at a temperature lower than that prevailing in the absorber A. This is an advantageous arrangement by reason of the fact that 'the' inert gas is materially 'cooled in the absorber A and the absorption solution is also discharged therefrom into the principal absorber A in a relatively cool condition which promotes absorption in the principal absorber.

. It is characteristic of this invention that the absorption, solution and liquid refrigerant are both circulated through a portion of the system solely by the sweeping and dragging action of the relatively high velocity stream of inert gas flowing through the same conduit. The propelling characteristics of the inert gas are functions of a number of factors which will be delineated generally below,

transient system disturbances, as fully described in my co-pending application Serial No. 248,671,

' filed- December 31, 1938. This arrangement is also advantageous because it permits the level of the absorber to be substantially independent of the level of the boiler" as the gas lift pump is ca- Lpable of elevating the liquid through a relatively very small or a relatively very great height as The propelling power of the inert gas stream is a function of its density. pressure, and velocity of flow through the evaporator or elevating absorbers. In general, an increase in the value of any one or more of the aboveenumerated factors results in an increase in the lifting power of the inert gas. Other things being equal, the

velocity of the inert gas will be a function of the eifective cross-sectional area of its path of may be desired without in any way affecting the.

conduit of a size suitable for domestic use havinch, a pressure differential of between two and four inches of water between the gas inlet and outlet connections to the evaporator or absorber,

and with a total system pressure ranging between 270 and 400 pounds per square inch. Under the conditions just enumerated it has been found that liquid will flow counter to the gas stream in a conduit, such as the counterflow absorbers disclosed herein, having an inside diameter of approximately one inch or more. These dimensions are illustrative only and are-not limiting since other conditions permit conduit sizes different from those mentioned.

A continuous stream of the inert gas traverses the evaporator and absorber and conveys the liquid refrigerant and absorption solution through horizontal or slightly sloping conduits by sweeping or dragging the liquid along the bottom of the conduit, but in substantially vertical or elevating conduits, such as the return bends connecting the substantially horizontal evaporator and absorber conduits, the gas is blowing through a body of the liquid. Therefore, in the horizontal or slightly inclined conduits the gas stream sweeps over a stream of liquid which it propels and agitates by exerting a frictional drag thereon; whereas, in thesubstantially vertical conduits the gas is blowing through a relatively large body of the liquid in the lower portions of such conduits with which it is in intimate contact. The friction and impact of the gas blowing through the bodies of liquid in the riser or elevating conduits drags or sweeps a portion of that liquid upwardly into the next conduit section. Thus, absorption takes place in the elevating absorbers through the action of a high velocity gas stream propelling a liquid through a horizontal or inclined conduit and through the action of a gas stream forcing itself through a body of liquid in an elevating conduit while conveying part of the body of liquid to a higher elevation. The gas and liquid contact in the evaporator is also of two types; that is, the gas sweeps or drags the liquid through horizontal or slightly inclined conduits and blows 'or blasts through columns of liquid in the elevating conduits of the evaporator.

Thus, in the instant disclosure the absorption solution is swept through a long sinuous conduit having a rather gentle incline in the portion 24 of the absorber A and is then elevated vertically at a rather rapid rate in the substantially vertical portion 30 of the absorber A. the vertical portion of the absorber the elevation takes the form of a plurality of short vertical steps connected by hdrizontal finned conduits.

Thus, in this form of the absorber the gas and liquid contact is of the most intimate character and both the liquid and the gas are in a constant state of turbulence and are constantly sbrubbing the wall of the absorber conduit to promote heat rejection therefrom which is a material factor in allowing this portion of the absorber to operate at a relatively low temperature.

The gas has been described as being propelled at a high velocity, but this is to be interpreted in relation to the other conditions prevailing within the system. For example, in the particular embodiment disclosed the gas velocity need be only of the order of a few feet per second in order to circulate the fluids and to promote effective upwardly through an evaporator or an absorber absorption and evaporation if a dense inert gas like nitrogen is utilized.

The .flow of inert gas through the evaporator and absorber is substantially continuous and steady though there is a pressure gradient from, the inlet to the outlet portions thereof due to the throttling action of the liquid, particularly in rising'conduits, on the gas stream. This insures substantially continuous uniform propulsion of liquid through the evaporator and absorber and continuous absorption of refrigerant whenever the refrigerating mechanism is operating.

The arrangement of the apparatus within the cabinet will now be described. The cabinet, which is generally designated at 42, comprises an insulated refrigerating compartment 43 which is closed by an insulated door 44. The cabinet construction includes a mechanism and storage compartment 48 which is located beneath the insulated storage compartment 43 and a rearwardly vertically extending cooling flue 41. The flue 41 has been shown somewhat exaggerated in depth in the accompanying drawings for the sake of clarity and enclosed by a rear panel 48 which may be provided with louvres at any desired point; as shown, there are a plurality of louvres 49 at the lower rear portion thereof and the bottom of the dine 41 is directly open to cooling air adjacent the surface upon which the cabinet is supported.

The gas heat exchanger G is partially embedded in the rear wall of the compartment 43 and in a removable insulated window element 5| through which the evaporator gas inlet and outlet connections I5 and I1 respectively pass. The ar- .,rangement is such that the evaporator, the win- However, in

condenser.

.vided to make the margin between the window element 5| and the rear wall of the compartment 43 completely air-tight.

The condenser C extends across the upper portion of the flue 41 in an inclined position whereby air which passes over any one portion thereof will not thereafter contact another portion of the The rectifier B may be formed on a vertical conduit or the conduit I! may extend transversely across the compartment 41 and adjacent the rear panel 48 thereof at about the way from the lower end of the air flue.

The lower tubular inclined portion 24 of the absorber A extends-upwardly and rearwardly at a slight incline from the mechanism compartment 46 to substantially the rear bottom portion of the flue 41 after which it joins the step by step substantially vertical upper portion 30 of the absorber A. The absorber A extends vertically in the lower portion of the flue 41 and inwardly of the elevating section 30 of the absorber A.

The boiler B, analyzer D, and the liquid heat exchanger L are encased in a suitable block of insulating material 55 and are positioned lengthwise of the compartment 46 but preferably adjacent one side wall thereof in such manner that the burner H is adjacent the removable front panel 5' of the compartment 46. The various conduits which interconnect the numerous elements constituting a complete refrigerating system are suitably arranged within thecompartments 4' and 41 as illustrated. The boiler is provided with a suitable waste products of combus- I system at such higher temperature.

,aaaaoea f sorber A'*is supplied with the coolest. available air and the air which flows'over any individual flightfor tube of the portion 2 of the absorber A does not thereafter contact another portion of thatabsorber and also by reason'of the step by step arrangement of the absorber section iii, anyair which is passed over the fins on one of the conduit sections II does not there after contact any other of such conduit sections whereby all are enabled to operate at a very low temperature. The absorber A, however, is for the most part contacted by air which has already passed oversome portion of the absorber A.

This is not objectionable in the present system by reason of the fact that the-stripping absorber A does not materially heat the air stream as the relatively small amount of heat'which is discharged therefrom is spread over a very great heat'rejecting area and, further, because of the fact that the absorber A normally'operates at a higher temperature than the absorber A and rejects the bulk of the heat of absorption froni the For this reason the absorber A may berelatively small insize. v

After the cooling air has traversed the various absorber sections it traversesthe rectifier and condenser and discharges from the top of the cabinet through the open top of the air cooling flue which may be covered with a screen, a reticulated plate or by some similar construction. It is apparent from Figure 1 that-with the arrangement herein disclosed a portion of the Y absorber and a portion of the evaporator overlie each other and that the remainder of the absorber is substantially vertically below the condenser and in the air flue and: rearwardly of the evaporator and the portion of the absorber coincident therewith.

Referring now to Figure 3, there is disclosed a modified form of the invention. Certainelements shown in Figure 3 are identical with cor- .respon'ding elements illustrated in Figures 1 and 2 and are, therefore, given the same reference characters primed. 1

In the form of the invention illustrated in Figure 3, there is provided a three-fluid absorption refrigerating system which is extremely compact and in which the mechanism compartment of the cabinet may be madeextremely shallow.

The absorber AA comprises a horizontal section 80 which is in the form of a continuous sinuous tube or conduit which is serially connected to a smaller horizontal section 8| which, as illustrated, comprises a single U-shaped tube. The conduit 82 which connects the absorber sections and GI may be positioned at one side of the apparatus as illustrated in Figure 3, or it may extend across the rear portion of the mechanism compartment 46' and rise at a gentle incline from the level of the absorber section 60 to the level of the absorber section 6!. The absorbersection 60 is provided with a plurality of fins 64 only one of which is shown. The fins 64 are offset upwardly from the tube 60 in order to provide for the most efficient form of heatreiection from the absorber and they, are constructed by stamping a continuous sheet of thin material with a plurality of deep slots 65 which serve substantially to prevent heat transfer between adjacent portions of. the fin whichare in intimate heat transfer relationship with adjacent conduits of the absorber section I and they are also provided with shallower but wider slots 65 which embrace the individual tubes of the absorber section 80. The absorber section Si is provided -with fins 61 which are constructed in the same manner in which the fins 64 are constructed.

In the form of the invention illustrated in Figure 3, the boiler B'- extends transversely of the compartment 46' and in the extreme rear portion thereof. As is apparent from Figure 3, l l the boilepanalyzen'liquid heat exchanger system is'in the extreme lower rear portion of the mechanism compartment 46' and the compartmeat 46' is so shallow that the top portion of the insulating block 55' extends up into the rear air-cooling flue 41" substantially to or above the level of the lowest portion of the bottom wall of the insulated storage compartment 43'. It is also to be noted that the absorber section "is at an elevation below the upper portion of the analyzer D.

In this form of the invention the lean solution discharged from theboiler is conveyed into the solution reservoir S by way of the conduit III,

the liquid heat exchanger L, and a conduit II which includes a looped vfin portion which'acts ,as a solution pre-cooler. conveyed from the solution reservoir S" into the The. lean solution is rich gas conduit i8 adjacent its point of connection with the absorber section 60 by means of a'gas lift pump II. The pump 2| corresponds to the pump 2| previously described.

However, there is nonecessity for a vessel such as the vessel 22 in this form of theinvention; therefore, the pump 2i discharges directly into the gas conduit. The strong solution which has passed through the absorberis. conveyed from the lean gas conduit 12 to the inner path of the liquid heat exchanger by means of a conduit 13 and it 'is conveyed from the liquid heat exchanger into the upper portion 'of the analyzer D by means of a conduit ll.

Th remaining portions of the apparatus are substantially identical with portions heretofore described and will not be described in detail herein.

Enlarged detail views of sections of the ab-- sorber AA are shown in Figures 4, 5 and 6. a

The absorber tubes are provided interiorly thereof with helical wire or ribbon inserts 8|. As illustrated the inserts 8| are triangular in cross-section to provide relatively elongated surfaces 82 which are inclined inwardly of the tube 80 in the direction of flow of thegas stream which is indicated by the arrows 83.

, The action of the insertsis depictedin Figures 5 and 6. As the-inert gas blows or sweeps the absorption solution alongthe tube the same is raised on one side of the tube in the direction of the advance of the helix due to the spiral motion which is imparted to the gas stream by the relatively rapidly flowing gas stream. Theliquid is not only raised along one side of thetube but it is also blown off the high end of the surface 82 in the form of a spray which intimately mixes with the gas stream and then forcibly strikes the wall of the tube at an oblique angle.

This action further splashes the liquid which also eiilciently imparts the heat of absorption to the tube because the helical motion of the gas and solution causes both to scrub the inner wall of the tube. The insert 8| causes the solution to form turbulent shallow pools 84 of the solution which rise on one sidethereof under the impetus f-the gas stream. The inserts 8| may be retained in the absorber tubes by frictional engagementwith the walls thereof or they may be secured to the'tube's by welding, brazing, timing or the like if desired.

The insert 8| increases the resistance ofiered by the absorber to the flow of the inert gas, however, that is compensated by the fact that the superior gas and liquid contact and the improved heat rejection permit the use of a smaller vessel. In particular the increased flow resistance is not material in an absorber such as that disclosed in Figure 3 as the inert gas is not called.upon

to elevate the liquid except for the small distance between the sections 60 and 6| of the absorber AA.

Though only one insert has been specifically disclosed other forms and arrangements may be provided if desired. For example, inserts having other cross-sections may be used and a plurality of axially spaced long pitch inserts may also be provided.

In the operation of this form of the invention a regulated and controlled quantity of absorption solution is fed into the rich gas conduit [8 adjacent its point of connection with the lower absorber section 60 by means of the gas lift pump 2|". through the horizontal absorber section 60, the

elevating conduit 62 and the absorber section 6| of the gas and liquid. After passing through the,

absorber section 6|, the strong solution is then returned to the analyzer as described heretofore.

Cooling air may be admitted into the bottom portion of the mechanism compartment 46' in any desired manner. As illustrated, cooling air flows directly through the bottom portion thereof. The cooling air passes over all portions of the absorber 60 and due to the arrangement thereof air whichfpasses over any one section of the fins 64 does not thereafter contact another portion of such fin and the deep slots 65 effectively prevent heat transfer between sections of the fin which are in heat transfer relationship with adjacent sections of the absorber 60. After passing over the absorber section 80 the cooling air flows to the right, as viewed in Figure 3, and thence upwardly through the flue 41'. Additional cooling air is admitted through the louvres 49' to flow over the righthand side of the absorber section 6|, as viewed in Figure 3, which is the last portion of the absorber in which the gas and liquid are in contact. This enables this section of the absorber to operate at a very low temperature. The air which is passed over the absorber section 60 flows over the left-hand side of the absorber section 6| before passing into the flue 41'.

In this form of the invention the utmost compactness of the a'pparatusis achieved by placing the absorber in a horizontal plane which is level with or even below the upper portion of the analyzer D. This permits the, mechanism com partment to be made of a minimum depth with a consequent saving in valuable cabinet space.

The liquid so supplied is propelled If desired, the absorber section 6| can be omitted'in whole orin part. If the absorber section BI is omitted, the conduit 62 will simply terminate in a separation vessel similar to the separation vessel 28 which will be drained to the liquid heat exchanger and will discharge the gas into the suction side of the circulating fan F.

While it is apparent that this form of the invention does not provide relatively as much absorbing area as that described in connection with Figure 1, it is highly satisfactory for small size units or for units adapted to be used in relatively cool climates where, exceptionally large heat rejecting areas are neither necessary nor much more compact and cheaper to manufacture.

In Figure '7 there is illustrated another modification of the invention, certain portions of which are identical with elements previously described in connection with Figures 1 and 2 and are therefore given the same reference characters double Primed with the exception of the absorber section to which subscripts will be appended to distinguish reference characters previously used.

This form of the invention is identicaLwith that disclosed in Figure 1 except in the following respects. The absorber section A: corresponding to the absorber section A of Figure 1, consists solely of a vertical section which is substantially identical with the section 30 of the absorber A. The boiler has been placed in the rear part of the mechanism compartment 46" and extends transversely thereof to provide space in the front portion of the compartment 46" to receive a vegetable drawer 98 which carries the closure 56" for the compartment 46".

If desired, still greater compactness in the assembly may be provided by moving the solution reservoir S" and the boiler-analyzer liquid heat exchanger assembly to the right, as viewed in Figure 7, so that the bottom portion of the chamber 46" may extend substantially to the level of the top of the insulating block 55". If this arrangement is desired, the absorbers A2 and A: may be elevated within the flue 44 in order to accommodate the solution reservoir substantially directly beneath the absorber A2. This construction will economize on cabinet space but it will also cut down on the available capacity of the storage bin 98 by the amount by which the depth of the chamber 46" is diminished.

In this form of the invention the cooling air enters the apparatus through the bottom portion of the compartment 46" and through the louvres. 49" and passes upwardly through the flue 4 1" over the absorbers A: and A's, the rectifier R",

and the condenser C" in a straight line path of flow offering a minimum resistance to the flow of cooling air and providing an extremely compact assembly which will permit the provision of a vegetable bin in the bottom portion of the apparazuss beneath the insulated storage compartmen Thus, in the course of the present invention there is disclosed in one form of the invention am ss;

cooling flue, so constructed and arranged to provide a system having maximum efiiciency concooled absorber, said apparatus being characterized by the fact that portions of said absorber are'positioned in said air duct and in said mech-' anism compartment, and means for circulating a mixture of inert gas and refrigerant vapor through said absorber portions with suflicent force to propel absorption solution therethrough.

sistent with extreme simplicity of construction and operation.

In still another form of the invention there is provided a refrigerating system in which all portions of the absorber are positioned in the rear air-cooling flue and in which the apparatus is arranged in a most compact manner and will provide for a vegetable storage bin in th .mechanism compartment beneath the insulated 'refrigerated storage compartment. In this form of the invention straight line air flow is provided for all air-cooled portions of the apparatus and the arrangement is such that a minimum resist: ance is offered to the flow of the cooling air.

It is within the purview of theinvention to reverse the absorber arrangements of Figures 1 and 7 that is, the elevating absorber may be supplied with the rich gas from the evaporator and the counterflowabsorber may act as a final stripping absorber. I

The absorbers utilized with the form of the invention disclosed in Figure 1 and 7 may also be provided in whole orin part with inserts such as that illustrated in Figures 4 to 6.

I claim:

1. Absorption refrigerating apparatus of the three-fluid type embodying an evaporator, a condenser, an absorber, and a boiler connected in circuit, a cabinet "having an insulated storage compartment, a lower mechanism compartment and a vertically extending side air flue, said apparatus being characterized byan air-cooled ab- 4. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a mechanism compartment below said food chamber and an upstanding air duct, an absorption refrigerating system of the type utilizing an inert gas including an evaporator positioned in said 7 chamber, a condenser, a boiler and a tubular aircooled absorber, said apparatus being characterized by the fact that it includes a horizontal portion of said absorber in said mechanism comtherethrough.

partment and another portion thereof in said air duct, and means for circulating a mixture of inert gas and refrigerant vapor through said absorber portion with suflicient force'to propel absorption solution therethrough.

5. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a mechanism compartment below said food chamber and an upstanding air duct, an absorption refrigerating system of the type utilizing an inert gas including an evaporator positioned in said chamber, a condenser, a boiler and a tubular aircooled absorber, said apparatus being characterized by the fact that said absorber lies in an inclined plane in said mechanism compartment, and means for circulating a mixture of inert gas and refrigerant vapor through said absorber with sufllcient force to propel absorption solution 6. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a mechanism compartment below said. food chamber and an upstanding air duct, an absorption refrigerating system ofthe type utilizing an inert gas sorber section in said flue, means for supplying absorption solution thereto and means for propelling a mixture of inert gas and refrigerant vapor to be absorbed through said absorber section under conditions such that the .absorption solution ispropelled through said section by the;

inert gas refrigerant vapor mixture;

2. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a

mechanism compartment below said food cham-' including an evaporator positioned in said charm. ber, acondenser, a boiler and a tubular air cooled absorber, said apparatus being characterized by the fact that said absorber includes a plurality of substantially horizontal vertically spaced offset conduit sections provided with heat rejecting'flns in said air duct, short lifting conduits connecting the adjacentends of adjacent substantially horizontal conduits whereby the cooling air rising through said duct does not pass over more than one set of fins on said oflset conduits, and means for circulating a mixture of inert gas and refrigerant vapor through said absorber portion with sufficient force to propel absorption solution the'rethrough.

7. Refrigerating apparatus-comprising a cabinet including an insulated food chamber, a mechrefrigerant vapor upwardly through saidabsorbe'r portion with sufficient force to propel-absorption solution upwardly therethrough. Y

3. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a mechanism compartment below said food chamber and an upstanding air duct, an absorption refrigerating system of the type'utilizing an inert as including an evaporator positioned in said I chamber, a condenser, a boiler and a tubular airanism compartment below said food chamber and an upstanding air duct, an absorption refrigerating system of the type utilizing an inert gas including an evaporator positioned in said chamber, a condenser, a. boiler and an air-cooled absorber having a horizontal portion consisting of a plurality of parallel serially connected tubes in said mechanism compartment and another horizontal portion consisting of a plurality of parallel serially connected .tubes in said air duct and positioned at an elevation above said first mentioned horizontal portion.

8. Refrigerating'apparatus comprising a cabinot including an insulated food chamber, a mechanism compartment below said food chamber and -an upstanding air duct, an absorption refrigerating system of the type utilizing an inert gas including an evaporator positioned in said chamher, a condenser, a boiler and a tubular aircooled absorber, said apparatus being characterized by the fact that said absorber includes an upstanding portion in said duct and another portion in said compartment, and means for circulating a mixture of inert gas and refrigerant vapor through said absorber portions with sufflcient force' to propel absorption solution therethrough.

9. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a mechanism compartment below said food chamber and an upstanding air duct; an absorption refrigerating' system of the type utilizing an inert gas including an evaporator positioned in said chamber, a condenser, a boiler and a tubular aircooled absorber, said apparatus being characterized by the fact that said absorber includes a portion in said air duct and an inclined tubular portion in said compartment, and means for circulating a mixture of inert gas and refrigerant vapor through said absorber portions with sufficient force to propel absorption solution therethrough. 10. Refrigerating apparatus comprising an insulated cabinet having a lower shallow mechanism compartment and an upstanding air flue, a three-fluid refrigerating mechanism including a ,boiler-analyzer in said mechanism compartment arranged with the analyzer extending n o'the lower portion of said air flue, a tubular air-cooled absorber lying in a substantially horizontal plane in said compartment and below the level of the upper portion of said analyzer, connections for the circulation of an absorbing solution through a, circuit including said absorber and said boileranalyzer, and means for circulating an inert gas refrigerant vapor mixture throughsaid absorber under conditions such that the absorbing solution is circulated thereby.

I 11. Refrigerating apparatus comprising an insulated cabinet having a lower shallow mechanism compartment and an upstanding air flue,

- a three-fluid refrigerating mechanism including a boiler-analyzerdn said mechanism compartment, a tubular air-cooled absorber lying in a substantially horizontal plane in said compartment, connections for the circulation of an absorbing solution through a circuit including said absorber and said boiler-analyzer, means for circulating an inert gas refrigerant vapor mixture through said absorber under conditions such that the absorbing solution is circulated thereby, said A absorber comprising a sinuous conduit provided exteriorly thereof with heat rejecting fins, and means within said conduit for imparting a helical motion to the inert gas refrigerant vapor mixture and for breaking the propelled stream of solution into a spray.

12. Absorption refrigerating apparatus. comprising a solution circuit including an absorber and a boiler, an inert gas circuit including said absorber and an evaporator, means for supplying refrigerant vapor produced in said boiler to said evaporator in liquid phase, said gbsorber comprising an elongated finned conduit, means for propelling an inert gas refrigerant vapor mixture therethrough with sufficient velocity to sweep or drag the absorption solution therethrough, and means withinsaid conduit arranged to present an obstructing surface to the flowof gas and liquid which is inclined inwardly oLsaid conduit in I the direction of such flow.

13. Absorption refrigerating apparatus comprising a cabinet including an insulated storage chamber, a mechanism compartment beneath said chamber and an air duct along one side of said chamber, an evaporator in said chamber, a generator in said compartment, a condenser in said air duct, a horizontal tubular absorber in said compartment comprising a sinuous tube having'a plurality of parallel tubular sections and a plurality of heat rejecting fins attached thereto and oii'set upwardly thereof each of said fins contacting each of said tubular sections and means connecting said evaporator, generator, absorber and :ondenser in circuit to form a refrigerating sys- 14. Absorption refrigerating apparatus comprising a cabinet including an insulated storage chamber, a mechanism compartment beneath said chamber and an air duct along one side of said chamber, an evaporator in said chamber, a generator in said compartment, a condenser in said air duct, a tubular absorber having portions thereof in said compartment and other portions thereof in said air duct at an elevation above said portions in said compartment, each of said portions of said absorber comprising a continuous tube and a plurality of heat rejecting flns attached thereto and offset upwardly thereof and means connecting said evaporator, generator, absorber and condenser in circuit to form a refrigcrating system. 15. Refrigerating apparatus comprising a boiler, a tubular air-cooled absorber, a condenser and an evaporator and a power driven circulator connected in circuit to form a three-fluid refrigerating system of the type in which absorption solution is circulated through said absorber by the frictional drag of an inert gas stream thereon, an insulate cooling chamber, a com- .partment extending low and along the rear wall of said chamber, means providing for flow of cooling air through said compartment, said condenser being mounted in an inclined position across the top of the vertically extending portion of said compartment, said absorber being mounted in an upright position in the lower part of the vertically extending portion of said compartment, said boiler being mounted adjacent the lower rear comer of said compartment but out of the direct path of flow of cooling air therethrough, and a storage chamber in the lower front portion of said compartment.

16. That improvement in the art of absorption refrigerating systems using a refrigerant, an absorbent therefor and a. gaseous medium inert with respect to the refrigerant and the absorbent which includes the steps of applying heat to a solution of the refrigerant in the absorbent to liberate refrigerant vapor, liquifylng the vapor, evaporating the liquid in the presence of gaseous medium, propelling solution weakened by generation of refrigerant vapor therefrom through an absorbing zone in heat transfer relationship with a stream of cooling air by the dragging' action of a propelled stream of a mixture of the gaseous medium and refrigerant vapor, imparting a swirling motion to said mixture and projecting the solution in the absorbing zone into the mixture of gaseous medium and refrigerant vapor in the form of a spray.

1'7. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and a pair of absorbers, a-solution circuit including a generator and said absorbers, means for supplying refrigerant vapor generated in said boiler to said evaporator in liquid phase.

- tions therethrough.

1 said absorbers respectively,

' .said absorbers beingconstructed of small crosssectional area conduit whereby the propelled stream of inert gas will circulate absorption solution therethrough and the other of said absorbers being constructed of larger cross-sectional area conduit whereby the inert gas and absorption solution may flow in opposite direc- 18, Absorption refrigerating apparatus comprising an inert gas circuit including an evaporator and a pair of absorbers, a solution circuit includinga generator and said absorbers, means for supplying refrigerant vapor generated in said boiler to said evaporator in liquid phase, means for circulating the inert gas through said inert gas circuit, a cabinet including an insulated storage chamber housing said evaporator and a vertical cooling air flue, said absorbers being mounted in upright positions in said flue, one of said absorbers being constructed of small cross-sectional area conduit whereby the propelled stream of-inert gas will circulate absorption solution therethrough and theother of said absorbers being constructed of larger cross-sectional area conduit whereby the inert gas and absorption solution may flow in opposite directions therethrough, said conduit of small cross-sectional area comprising a plurality of co-planar offset vertically spaced substantially horizontal sections serially connected by substantially vertical riser sections, air cooling fins-attached to said substantially horizontal sections, and an inclined section consisting of a sinuous flnned conduit positioned at least in part beneath said insulated storage chamber.

19. Absorption refrigerating apparatus of the three-fluid type embodying an evaporator, a condenser, an absorber, and a boiler connected in circuit comprising a cabine'thaving an insulated storage compartment, a lower mechanism coma,aes,esa

sorption refrigerating system comprising an elongated conduit, heat rejecting flns mounted on the exterior wall of said conduit, and a helical obstructing element extending along the inner wall of said conduit, said obstructing'element being formed to provide an inclined surface on one wall thereof extending inwardly of said conduit.

22, Absorption refrigerating apparatus of the three-fluid type embodying an evaporator, a condenser, an absorber and a boiler connected in circuit, a cabinet having an insulated storage chamber housing said evaporator and a heat repartment and a vertically extending side air flue,

said absorber including an air-cooled section in said flue positionedabove the level of the lower part of said storage compartment, and an air-' cooled section in said mechanism compartment, said absorber sections being so arranged with respect to said flue thatthe air streams passing over each of said "sections are substantially independent.

20. Absorption refrigerating apparatus of'the three-fluid type embodying-an evaporator, a.

condenser, an absorber,-and a boiler connected in circuit comprising a cabinet having an insulated storage compartment, a'lower mechanism compartment and a vertically extending side air flue, said absorber comprising a conduit provided with heat rejectz'gflns lying :in said mechanism compartment, said evaporator being positioned in said storage compartment directly above said absorber, means for supplying refrigerant vapor produced 'in said 'boiler to the bottom portion of said evaporator in liquid phase, means for supplying absorption solution'to said absorber,

and means for propelling an inert gas refrigerant vapor mixture through a circuit including said evaporator and said absorber with suflicient tions therethrough, saidsolution and inert gas boiler, said absorber comprising an elongated flnned conduit, means for supplying absorbing solution thereto, and power driven means for circulating an inert gas through said conduit with sumcient velocity to propel the absorbing solution therethroug-h, the direction of flow of the inert gas and absorbing solution through said conduit being such that they flow in the same general direction as the cooling air flowing through said chamber.

23. Refrigerating apparatus comprising a cabinet including an insulated food chamber, a mechanism compartment below said food chamber and an upstanding air duct, an absorption refrigerating system of the type utilizing an inert gas including an evaporator positioned in said chamber, a condenser, a boiler, a tubular air-cooled absorber, and means for propelling an inert bas through said absorber with a velocity suflicient to sweep or drag the absorption solution therethrough by the frictional drag of the inert gas, said apparatus being characterized by the fact that said absorber includes a horizontal portion in said mechanism compartment and another horizontal portion in said air duct.

24. Absorption refrigerating apparatus compelled stream of inert gas will circulate absorption solution therethrough, the other of said absorbers being constructed of larger cross-sectional area conduit whereby the inert gas and absorption solution may flow in opposite direccircuits being arranged in such'fashion that inert gas is supplied to the bottom portion of both of said absorbers and solution is supplied to the bottom portion of said small cross-sectional area. absorber and to the upper portion of said larger cross-sectional area absorber.

25. Absorption refrigerating apparatus comprising an inert gas circuit including an evaporatorand a pair of absorbers, a solution circuit including a generator and said absorbers, means a for supplying refrigerant vapor generated in said force to propel the liquid refrigerant and the absorption solution throughJsaid evaporator and 1 21.'An;absor .adai t d,for use in an abboilerto said evaporator in liquid phase, means for circulating the inert gasthrough said inert gas circuit, a cabinet including an insulated storage chamber housing' said evaporator and a vertical cooling air flue, said absorbers being mounted in upright positions in saidflue, one

- prising a solution circuit including an absorber and a boiler, an inert gas circuit including said absorber and an evaporator, means for supplying refrigerant vapor produced in said boiler to said evaporator in liquid phase, said absorber comprising an elongated-finned conduit, means for propelling an inert gas refrigerant vapor mixture therethrough with suificient velocity to sweep or drag the absorption solution therethrough, and a helical ribbon having an inclined face in said conduit, said ribbon being arranged in such fashion that the gas and liquid always ride over the inclined face thereof.

27. Refrigerating apparatus comprising a cabinet construction including a cooling compartment and a machinery and heat rejecting compartment, an absorption refrigerating mechanism associated with said cabinet including an evaporator, an absorber, a boiler, an upstanding analyzer, means for conveying enriched absorption solution froni said absorber to said analyzer, and a condenser connected in circuit, said evaporator being positioned in said cooling compartment and the remaining parts of said refrigerating mechanism being positioned in said machiner'y compartment, said apparatus being characterized by the fact that said absorber comprises a horizontal air-cooled portion positioned below the portion of said analyzer which receives absorption solution from said conveying means.

28. Refrigerating apparatus comprising a cabinet construction including a cooling compartment and a machinery and heat rejecting compartment, an absorption refrigerating mechanism associated with said cabinet, an evaporator in said cooling compartment-and an absorber in said machinery compartment connected to said evaporator to form an inert gas circuit, a boiler assembly in said machinery compartment connected to said absorber to form an absorption solution; cirduit, 'means .for liquefying refrigerant vapor produced in said boiler assembly and for supplying the liquid to said evaporator, said apparatus being characterized by the provision of a horizontal air-cooled section of said absorber located below the upper portion of said boiler assembly and means in said inert gas circuit for forcing the inert gas to flow through said absorber with a velocity suificient. to sweep or drag the absorption solution therethrough.

29. Refrigerating apparatuscomprising a cabinet construction including a cooling compartment and a machinery and heat rejecting compartment, an absorption refrigerating mechanism associated with said cabinet, an evaporator in said cooling compartment and an absorber in said machinery compartment connected to said evaporator to form an inert gas circuit, a boiler assembly in said machinery compartment connected to said absorber to form an absorption solution circuit, means for liquefying refrigerant vapor produced in said boiler assembly and for supplying the liquid to said evaporator, said apparatus being characterized by the provision of a horizontal air-cooled section of said absorber 10 located below the upper portion of said boiler assembly and another portion positioned above said boiler assembly, and means in said inert gas circuit for forcing the inert gas to flow through said absorber with a velocity sufllcient to sweep or drag the absorption solution therethrough.

30. An absorber adapted for use in an absorption refrigerating apparatus of the type utilizing an inert pressure equalizing medium comprising an elongated conduit formed to provide a plurality of parallel straight runs connected by return bend portions all lying in a common plane, a plurality of identical heat rejecting fins attached to said absorber, each of said fins being constructed and arranged in heat conducting relationship with consecutive straight runs of said conduit, inert pressure equalizing medium supply and discharge connections for said conduit, and absorption solution supply and discharge connections for said conduit.

31. An absorber adapted for use in an absorption refrigerating apparatus of the type utilizing an inert pressure equalizing medium comprising an elongated conduit formed to provide a plurality of parallel straight runs connected by return bend portions all lying in a common plane inclined to the vertical, a plurality of identical heat rejecting fins attached to said absorber, each of said fins being constructed and '40 arranged in heat conducting relationship with consecutive straight runs of said conduit, inert pressure equalizing medium supply and discharge connections for'said conduit, and absorption solution supply and discharge connections for said conduit.

32, Absorption refrigerating apparatus comprising a cabinet structure having an insulated refrigerating chamber and a mechanism compartment extending below and alongone wall of said refrigerating chamber, said refrigerating chamber being arranged for circulation of cooling air therethrough, an evaporator in said refrigerating chamber, a tubular air cooled condenser -in said mechanism compartment con- 5s nected to supply refrigerant liquid to said evaporator, a generator in said mechanism compartment connected to supply refrigerant vapor to said condenser, an absorber in said mechanism compartment comprising a plurality ofparallel 60 straight runs serially connected by return bend portions, a plurality of identical heat rejecting fins in heat conducting relationship with said straight runs of said absorber, each of said fins being positioned in heat conducting relationship og-with a plurality of said straight runs, means providing for circulation of absorption solution between said generator and said absorber, and means providing for circulation of inert gas between said evaporator and said absorber.

GEO; AJBRACE.

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