US2315356A

US2315356A - Refrigeration

Info

Publication number: US2315356A
Application number: US328196A
Authority: US
Inventors: Arnold D Siedle
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1940-04-06
Filing date: 1940-04-06
Publication date: 1943-03-30
Anticipated expiration: 1960-03-30

Description

March 30, 1943. A. D. SIEDLE REFRIGERATION Filed April 6, 1940 3 Sheets -Sheet 1 INVENTOR Arnold D. qS'l'edle ATTORNEY March 30, 1943. A. D. SIEDLE REFRIGERATION Filed April 6. 1940 5 Sheets-Sheet 2 Arnold 0. Siedle ATTORNEY Patented Mar. 36, 1943 REFRIGERATION V Arnold D. Siedle, Canton, Ohio, assignor to The Hoover'Company, North Canton, Ohio Application April 6, 1940, Serial No. 328,196

' 27 Claims. (01. 62-1195)- This application relates to the art of. absorpf. tion refrigerating apparatus and more particu-' lariy to a ,novel construction of such apparatus which provides refrigeration at a plurality of temperature levels.

Heretofore attempts have been made to pro vide absorption refrigerating machines which will produce refrigeration simultaneously at a plurality of temperature levels. These machines meet the technical difficulty that the necessary high temperature evaporating level, which preferably should be above the freezing point of water to eliminatethe, frost problem, necessitate the .use of prohibitively large evaporating elements and even then tend to collect frost at certain localized areas thereof and do not provide desirable .distribution of the refrigerating eifect. Another dimculty with prior systems is due to the fact that very low temperature refrigeration is difllcult to achieve in the low temvide an absorption refrigerating machine in which refrigeration is produced at different temperature levels by evaporation of refrigerating medium which is fractionally condensed from the vapors produced in the generator.

Itis another object of the invention to utilize v the condensate produced by rectification of vapors produced in the boiler as a refrigerating fluid before returning such condensate to the boiler.

It is a further object of the invention to reject a portion of the heat of the vapors produced by the boiler of an absorption refrigerating system at a high temperature level and to reject the balance of the heat of such vapors at a low temperature level.

perature refrigerating element because of the presence of small amounts of absorbing solution which find their way into the evaporator. Necessarily prior systems are limited to a rather narrow range of refrigerating temperatures due to the inherent limitations involved in the use of a single refrigerant within the system.

It is a principal object of the invention to provide a multi-temperature three fluid absorption refrigerating system which avoids the above mentioned diiiiculties and possesses numerous other advantages peculiar unto itself.

It is a principal object of the present invention to provide an absorption refrigerating apparatus in which refrigeration may be produced at a plurality of separated temperature levels within a single system.

It is a further object of the present invention ant produced in a condenser into a pressure equalizing medium and in which higher temperature refrigeration is produced by evaporation into a. pressure equalizing medium from a solution of the absorbent medium and refrigerant medium which solution is condensed in a separate condenser or rectifying element.

It is an object of the present invention to pro- It is another object of the invention to produce a plurality of cooling mediums within a single absorption refrigerating system by fractional condensation of vapors expelled by the application of heat to a solution of a refrigerant and an absorbent.

It is a still further object of the present invention to provide a compact and economical arrangement of a multi-temperature refrigerating mechanism in a cabinet construction to the end that a minimum of space is utilized by the refrigerating mechanism and to the further end that the rejection of heat from various heat re- Jecting elements of the apparatus is allowed to proceed in a highly efficient fashion.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with accompanying ,drawings, in which Figure 1 is an elevational sectional view of a refrigerating mechanism embodying the present invention.

Figure 2 is a partial section and partial dia- 4f grammatic perspective view of a modified form ating system which comprises an insulated cabinet ll having an upper low temperature com-- partment l2 which is separated from a lower high temperature refrigerating compartment l3 by means of an insulated partition I which is, or

may be, made integrally with the cabinet wall..

The compartments l2 and I3 are provided with suitable insulated pivoted closures or doors l5 and i6, respectively. The cabinet construction also compartment ii. A solution reservoir 8 is positioned just above the liquid heat exchanger L and an inclined tubular air-cooled absorber A extends forwardly and downwardly of the compartment l8 from a position beneath the flue IS. A circulating centrifugal fan F which is driven by a sup rposed electric motor M, is mounted in the corner of the compartment l9 lustabove the absorber A. A slightly inclined tubular air-cooled rectifier R, or primary condenser, extends transversely of the compartment is at an intermediate level therein and a tubular air-cooled condenser C is mounted in the upper portion of the chamber IS. A low temperature evaporator E is mounted in the compartment l2 and a high temperature evaporator E i mounted in the compartment II. A gas heat exchanger G is in.- serted in the rear insulated wall of the compartments l2 and I3 and extends vertically therein. The evaporators E and E are inserted into the compartments l2 and I3, respectively, through openings 2' and 21, respectively, which are shaped to receive the evaporators E and E. The openings 28 and 21 are closed by suitable insulated closure panels 28 and 28, respectively, and each is sealed by a suitable gasket 30.

I The elements of the above described refrigerating apparatus are suitably connected by various conduits to form a plurality of gas and liquid circuits which constitute a complete refrigerating mechanism.

- The refrigerating mechanism will be charged with a suitable refrigerant such as ammonia, a suitable absorbent therefor such as water and a erant in the absorbent. In the case of ammonia and water, for example, the rectifier R maybe designed to produce a condensat which is composed of approximately 20 percent absorbent and 80 percent refrigerant. Due to the fact that the element R condenses an appreciable quantity of the ammonia vapor, the vapors discharged therefrom to the condenser through the conduit 33 are substantially pure anhydrous ammonia and have had their temperature lowered to a point approaching thecondensing temperature. Therefore a part of the condensing load is carried, by the element R which rejects an appreciable quantity of heat at a high temperature level and may be made relatively small in size as compared with the quantity of heat which it is called upon to dissipate.

The substantially pure anhydrous ammonia or refrigerant vapor which is supplied to the upper; end of the condenser C, is liquefied therein by heat exchange relationship with the cooling air flowing through the flue II. The resulting liquid ammonia is conveyed from the condenser C to the bottom portion of the evaporator E by means 'of a conduit 85 which includes-1. downwardly extending U-sha'ped portion adapted to form a pressure balancing liquid column. The conduit l5 Joins the evaporator E adjacent its point of suitable pressure equalizing medium, preferably a dense inert kas like nitrogen.

A suitable gas burner or similar source of heat H, is mounted in the compartment I! in a position to heat the boiler B. The gas burner H and the electric motor M are controlled in a manner to be described hereinafter.

The application of heat to the boiler 13 gencrates re rigerant vapor and some vapor of the absorbin solution from the rich solution normally therein contained. The vapor so produced passes upwardly through the analyzer D in counterflow lationship with absorbing solution flowing do wardly therethrough and which is supplied from a source to be described hereinafter. In the analyzer, further refrigerant vapor is added to the vapor supplied from the boiler and some of the absorption solution vapor is removed from such vapor.

After passing through the analyzer D, the partially purified vapors are conveyed therefrom to the lower end of the slightly inclined tubular aircooled rectifier R by means of a conduit 32. In this construction, the element R performs the usual function of a, rectifier but it also abstracts sufliclent heat to condense a part of the ammonia vapor supplied thereto by the conduit 32. Consequently, the condensate formed in the rectlfler R is a very strong solution of the refrigconnection with the gas supply conduit 36.

Lean inert gas which is produced in the absorber is conveyed fromthe upper portion thereof into the suction side of the circulating pump F by means of the conduit 38 and after being placed under a slight pressure by the fan, it is conveyed therefrom to the bottom portion of the evaporator E by way of conduit 3!, the outer pass of the gas heat exchanger G and the aforementioned conduit Ii.

It is apparent that the pressure prevailing in the conduit 36 will approach that prevailing in the discharge conduit 39 of the fan. It is disadvantageous to permit this pressure to be reflected back through the condenser to the boiler and for this reason the condenser side of the .U-shaped conduit 35 is vented to the rich gas side of the gas .heat exchanger G by means of a conduit 40. The pressure differential between

conduits

40 and 36 is balanced by a liquid column in the conduit 35.

The evaporator E comprises a pair of vertically spaced substantially horizontal pipe coils 4| and 42 which are serially connected by a suitable riser conduit 43. The form of the evaporator E is preferably substantially identical with that disclosed in connection with the modification illustrated in Figure 2 to be described hereinafter. Evaporator E is provided with an anti-blocking drain 5 which is connected between the upper portionof the bottom coil 4| and the rich gas side of the gas heat exchanger G.-

The conduits forming the evaporator E have arelatively small cross-sectional area whereby the inert gas stream flows therethrough with a velocity sufllcient to propel the liquid refrigerant therethrough by the frictional drag exerted on the liquid by the inert gas stream. Consequently the liquid refrigerant supplied by the conduit 35 is circulated through all portions of the evaporator E by the inert gas as the liquid is evaporating into the inert gas.

The evaporator E is supplied with substantially pure anhydrous liquid ammonia and with very,.. lean inert gas. Therefore it operates at a'teiiiperature materially below the freezing point bi water.

changer-VG, the resultinginert gas is discharged into the bottom portion of the evaporator coil EU The evaporator coil E, as illustrated, is posiwhereby the inert gas will flow therethrough at a relatively. low velocity. -The vertically extending coil 50 is preferably bonded to a vertically extended air cooling plate ii in order to provide a large heat transfer area The condensate formed in primary/condenser element R is conveyed from I tioned ina substantially vertical position and is the rectifier and v the lowerend thereof into the upper .endof the coll-iii by =means of a U-shaped. liduldsealing conduit 52 which passes into the rear'wall .ofthe cabinet construction. The coil 50 lslprovided.

with a slight continuous downward slope where-I by the ammonium hydroxide 'wmen .isiusupplled thereto from the rectifier It may no downward ly by gravity in counterflow relationship to the inert gas stream which flows upwardly through,

the coil 50..

In the evaporator E the refrigerant is rich ammonium hydroxide solution 'and its boil.,.-

ing point at the partial "pressure prevailing in the coil; iii is appreciably above the bollin'g'point of the anhydrous ammonia which issupplied to the evaporator EL Consequently, evaporation which occurs into the inert gas stream flowing through the coil 50 from the ammonium hydroxide supplied .thereto occurs at a temperature which is above the freezing point. of ice in order to prevent formation of frost on the coil 50 and plate 5i but which is sufficiently low in view of of the boileranalyzer system which is vented through the conduit 40 to the rich gas side of the as heat exchanger G.

The lean solution is conveyed from the reservoir 8 to the suction conduit '3! of the fan which opens directly into. the upper end of absorber A by means ofthe conduit 5B which includes a finned portionv I! in order to precool the solution and discharges into a gas lift pump conduit Bl which opens directly into the conduit 38. Pumping gas is conveyed, by a conduit 6i from the discharge conduit 3! of the fan into the gas lift pump conduit 80 at a point below the liquid level normally prevailing therein. Consequently, the lean solutlon is elevated into the upper end of the absorber by gas lift action.

The lean solution flows downwardly through the absorber by gravity in counterflow relationship with the inert gas refrigerant vapor mixture flowing upwardly therethrough and becomes enricher! in the manner heretofore described.

it thus completing the absorption solution cir-' cult.

the heat transfer area provided by the plate ii ,5

to maintain .safe refrigerating temperatures within the compartment [3. The rectifier is preferably so designed that it will form a solution of .the refrigerant in the absorberof such strength that safe refrigerating .temperatures will be maintained in the compartment l3 without forming frost on the cooling elements therein. As has been indicated above. a solution containing approximately 20 percent absorbent and 80 percent refrigerant is one example of. the solution suitable for this purpose. i

After traversing the coil the enriched inert gas is conveyed from the upper end thereof to the bottom portion of the absorber A by means of the conduit 54. The rich inert gas then flow upwardly through the absorber A in counterflow to lean solution flowing downwardly therethroug h with the result that the solution is enriched by absorption of the refrigerant vapor content of the inert gas and the resulting heat of absorption is rejected to cooling air flowing over the exterior walls of the absorber conduit and the cooling fins attached thereto. The resulting lean inert gas is then conveyed by the conduit 38 into the fan in the manner described heretofore.

The lean solution formed in the boiler B by the generation of refrigerant vapor therefrom is conveyed from the boiler to the solution reservoir S by way of conduit 55, the liquid heat exchanger L The material supplied to the evaporator E will not evaporate totally and there will be a material residue which will flow from the lower end of the coil 50 into the bottom portion ofthe gas heat exchanger G from which it is drained into the rich gas returnconduit 54 by means of the conduit 08. The conduit 68 includes a U-shaped portion to form a short pressure balancing column "to balance the'pressure differential which exists between the bottom portion of gas heat exchanger I G'and the conduit 54. This pressure differential is brought about by the drop in pressure which occurs in the inertgas as it flows through the coil 50. This residue solution then flows through the conduit N and into the strong solution and into the conduit 83 where it mingles with the strong solution discharged from the absorber and then returns to the boiler system in the manner heretofore described.

For purposes of illustration, the boiler 13 herein has been shown as being heated by a suitable gas burner H to which gas is supplied by means of a suitable conduit It which includes a solenoid control valvell. A suitable by-pass I2 is provided around the valve II in order to supply fuel for a small igniting pilot flame which will be maintained on the burner H when the valve H is in closed position. The burner H. also includes a suitable flame failure safety cut-off device 13 of a known type.

Electricalenergy for operating the electrical motor M and the solenoid valve H is provided by means of a pair of electrical conductors 14 'H. The conductor I8 is also connected to the electrical motor M by means of an electrical conductor I9. A second thermostatic switch 80 is bridged across the conductors I5 and I8 in parallel relationship with the thermostatic switch 'll by means of'a pair of electrical conductors respond directly to the temperature of the evaporator. The switch 80 will be placed within the compartment I 3 preferably in a position to respond to the temperature of the air circulating therethrough. The switches II and 80 have been illustrated diagrammatically herein but it is to be understood that known types of variable refrigerant controls may be substituted for each of these thermostatic switches within the scope of the present invention.

It is apparent from the electrical circuitthat completion of the circuit by either of the switches 11 and 80 will simultaneously energize the motor M of the circulating fan F and will energize the solenoid valve 'II to raise the same to open position whereby a full flame will be carried upon the burner H and sufficient heat will be applied to the boiler B to generate refrigerant vapor and vapor of the absorption solution therefrom.

Preferably each of the coils I and 42 is provided with an overlying flat metal plateiii which forms a support for stutablexeceptacles such as ice tray 86. The space within the compartment I2 beneathhthe coil may.be utilized for refrigerating foodstuffs and a suitable tray 0'I may be provided for this purpose.

It is preferred to mount an elongated narrow condensate collecting pan 88' in the lower portion of the compartment I 3 directly beneath the plate 5| to collect moisture dripping. In the normal operation of the apparatus there will be some collection of moisture on theplate SI and coil 50 which will not freeze into frost because these elements will operate at a temperature above the melting point of ice. A high relative humidity will be maintained in the compartment I3 because of the relativehr high temperature of the refrigerating elements. These conditions are particularly desirable in order to provide desirable refrigeration of foodstuffs without drying the same by moisture collecting in the form of frost in a low temperature evaporator. The high humidity which will be maintained in the compartment I3 will inhibit serious loss of moisture from foodstuffs stored therein.

The bottom portion of the compartment I! which is formed by the base element and particularly that portion of the compartment I8 directly under. the chamber I0 will be provided with suitable openings or will be left substantially entirely open to allow free flow of cooling air into the compartments I8 and I9. Cooling air will flow first over the solution precooler 58, then over the air-cooled absorber A, then over the.

rectifier and primary condenser R, and ultimately over the condenser C after which it will exhaust through the top portion of the compartments or ducts 19.

The present invention provides a refrigerating mechanism in which separate refrigerating elements are placed in distinct'refrigerating chambers and are supplied with refrigerants having different characteristics but all coming from 8 gen and higher temperature refrigeration-will.

be produced by evaporation from a solution of ammonia in-water, ammonium hydroxide, into the inert gas; and-both the anhydrous ammonia and the ammonium hydroxide will be supplied from a sing'lerefrigerating system.

Due to the parallel connection-of the control switches TI and 80, the refrigerating mechanism" will be energized to produce refrigeration whenever there is demand for refrigeraiton in either of A the compartments It or I3 and such production of refrigeration will continue until such time as the refrigerating demands of both compartments havebeen satisfied. This insures that no part of the apparatus whatever will be without ability to meet its refrigerating load.

Referring now to Figure 2, there isillustrateda modified form of the inventions This 'form of the invention is identicalwith that disclosed in Figure 1 except for the arrangement of the high temperature refrigerating element. Conseq'uent ly, the refrigerating mechanisms relationship to the cabinet structure has not been shown except the relationshipof the evaporating elements to the refrigerating compartment.- -It will be under-- stood that this arrangement is identical with that disclosed in Figure 1. In order to eliminate needless duplications of description, those portions of the mechanism of Figure 2 which are identical with portions of the apparatus previous ly described in connection with Figure 1 are given the same reference charactersprimed except that the low temperature-evaporator is given a subscript I. v

In this form of the invention the high temperature refrigerating compartment I3 is refrigerated by a' horizontal coil I00whi'ch lies in the upper portion thereof or just below the mad-- lating dividing panel II. A sheet metal heat transfer plate MI is mounted in heat exchange relationship with the under side of the coil I00 in order to provide a large heat transfer area.

The inert gas flows from the circulating fan F through the evaporator E1 and discharges through the conduit 46' into the inner pass of the gas heat exchanger exactly in the manner heretofore described in connection with the cor responding elements of Figure 1. The partially enriched gas then .flows through the inner pass of the gas heat exchanger G and is conveyed from the bottom end thereof into one end of the horizontal coil I00 by means of conduit I03. The inner pass of the gas heat exchanger G is drained to the strong solution return conduit 63' by a drain conduit I01.

The evaporator coil I00 is made of a small diameter conduit whereby the inert gas flows therethrough with a velocity su'fficient to propel or distribute the liquid refrigerant therethrough by the frictional drag of the inert gas stream. The condensate formed in the rectifier R is'conveyed from the lower end thereof into the coil I00 adjacent its junction with the conduit I03 by means of a downwardly extended U-shaped con-' duit I05 which will provide a pressure balancing column to maintain the pressure differential which normally exists between the conduit I03 and rectifier R.

The condensate which is discharged into the coil I00 is propelled therethrough by the inert the gas which is evaporating and produces refrigeration at a temperature which is low enough to maintain safe refrigerating conditions in the compartment it but which is high enough to maintain a relatively high-humidity condition in the compartment 13'.

The rich gas and unevaporated liquid which completely traverses the coil I -is .conveyed therefrom to the bottom portion of the absorber A by means of conduit I06. The gas then flows upwardly through the absorber in-the manner described in Figure 1 and the liquid flows through the conduit 63' and ultimately returns through the conduit 64' to the upper portion of the analyzer D..

This form of the invention operates identically with that .described heretofore in connection with Figure 1 and will be provided with an identical control and heating system.

In this form of the invention, however, the high temperature evaporator is horizontally positioned in the upper portion of the high temperature compartment 13' whereby it consumes a minimum of. space therein and the refrigerating liquid supplied to the coil I00 flows therethrough in parallel flow relationship with and under the propelling force of the inert gas as distinguished from the arrangement disclosed in Figure 1 in which the liquid refriger'antin the-coil 60 flows by gravity in counterilow relationship to the inert gas. Also in this form of the invention, the openings and inserts therefore in the rear wall of the cabinet will naturally extend transversely thereof on a horizontal plane instead of vertically as is the case in connection with the apparatus described in connection with Figure 1 because. of the horizontal evaporator construction used in the compartment l3.

Referring now to Figure 3 there is disclosed another modified form of the invention in which the inert gas is circulated by the density differential existing between'cold rich gas discharged from the evaporator and warm lean gas discharged from an absorber and in which the absorbing solution is circulated by means of a heat operated vapor lift. pump.

The cabinet construction preferably utilized in this form of the invention is identical with that preferably utilized in the form of the invention discussed above in connection with Figure 1. Therefore, only a portion of the cabinet 'hasbeen shown in order to illustrate its relationship to the cooling elements and identical portions of the cabinet in Figures 1 and 3 have been given the same reference characters except those in Figure 3 are double primed.

This form of the invention comprises a boiler 20!, an analyzer 20i, an elongated slightly inclined tubular finned rectifier and primary condenser 202, a tubular air-cooled condenser 202, 'a low temperature evaporator 204, a high temperature evaporator 205, a gas heat exchanger 206, an inclined tubular air-cooled absorber 201, a solution reservoir 208, and a liquid heat exchanger 209. These elements are suitably connected by various conduits to form a completerefrigerating system.

The thus described refrigerating system will be charged with a suitable refrigerant such as ammonia, a suitable absorbent therefore such as water, and a pressure equalizing medium preferably a light inert gas like hydrogen.

The control mechanism for this form of the invention may be identical with that disclosed in connection with Figure 1 except that there will be no connection for controlling a circulatingfan.

The application of heat to the boiler 200 produces vapor of refrigerant and absorption solution therein which flows upwardly through the vapor lift pump 2i. and conveys solution upwardly therethrough into the separation chamber 20L From. the separation chamber. 2, the

vapors are conveyed to thelowerend of therectifier 202, by means of the conduit 2! I After passing through the rectifier 202, the resulting anhydrous ammonia-vapor is conveyedtherefrom tothe upper end of the condenser 202 by means of conduit 2l2.. The vapor isthen liquefiedin the condenser, and is discharged therefrom through the conduit 2i! into the upper coil 2 of the evaporator 20!. I

The evaporator coil 2 is given a slight downward inclination in order to provide for gravity flow of the liquid refrigerant therethrough. .The coil 2i 4 is in heat exchange relation with a plate 2il which is preferably ofv aluminum and has a horizontal upper surface. The distance between the horizontal upper surface of the plate 2i! and the coil positioned therebelow increases from the liquid inlet portion of the coil to the liquid outlet portion thereof. C0112 is serially connected to a lower identical coil 2|! by means of a conduit 2ll.- The coil 2i. is likewise in heat exchange relationwlth a heavy plate 2i5.

Lean inert gas-formed inrthe absorber 2" is conveyed therefrom to .one end of the lower coil 2| of the evaporator'by-way of the conduit Ill,

the outer pass of the gas heat exchanger 200 and the evaporator gas supply conduit 2".

The inert gas flows upwardly through the evaporator 2l4in counteriiow relationship with the liquid refrigerant flowing downwardly therethrough. The liquid refrigerant evaporates into the inert gas which produces refrigerating effect at a low temperature.

from flowing into the gas heat exchanger. After traversing the gas heat exchanger, the inert gas than flows through the conduit 224 into the bottom portion of an evaporator coil 226 which has attached thereto an extensive air cooling plate 220.

The condensate formed in the rectifier 202 is conveyed .from the lower end thereof into the upper end of the coil 228 by means of a U-shaped conduit 221. The liquid refrigerant flows downwardly through the coil 225 by gravity in counterflow relationship to the inert gas flowing upwardly therethrough. The refrigerant evaporates into the inert gas to produce a refrigerating effeet at a temperature such that frost deposition upon the coil 225 and plate 228 will be inhibited and safe refrigerating temperatures will be maintained in the compartment |3'-.

The resulting rich gas'formed in the coil 225 is conveyed from the upper end thereof to the bottom portion of the tubular inclined absorber 201 by means of a conduit 230. The rich inert counterflow relationship with the lean absorption solution flowing downwardly therethrough. The refrigerant vapor content-of the gas is absorbed in the liquid and the resulting heat of absorption is dissipated to cooling air flowing over the exterior walls of the absorber conduit and the cooling fins attached thereto. Resulting lean gas is then discharged from the upper end of the absorber bymeans of the conduit M8 in the manner 'described above. Y

Circulation of inert gas is achieved in the following manner: A cold dense column of gas discharging through the conduit 222 is maintained in the inner pass of the gas heat exchanger 208. This gas has a greater weight than the warmer and-lighter lean gas which is flowing upwardly through the outer pass of the gas heat exchanger from the absorber... There is also maintained a. cold dense, rich gas column in the conduit 230 which has a greater average density than the gas column in the evaporator coil 22!. These factors contribute to produce a circulation of the inert as by gravity.

Although the evaporator for the compartment 13', has been described as a vertical pipe'which may be positioned adjacent one side. or the rear wall of the compartment "I3", it is within the scope of the present invention to place this coil in a horizontal position inclined slightly to produce flow in the top part of the compartment ll just beneath the partitionfl";

The loan solution which is discharged the separation chamber!" =by-th'e vapor lift pump- 2|. is conveyedntherefrom to the upper end of the absorber 281 by gravity through the conduit 2; the liquid heat exchanger 2 and conduit l. The absorbing solution flows downwardly through the absorber 20l'by gravity counter tothe-inert gas flowingupwardly therethrough and is strengthened by'absorbing refrigportion of the coil 22! to the boiler by means of the conduit 2, the conduit 22! and the boiler return conduit '22 I It will be understood that the absorber, rectifler, condenser, and boiler will be arranged in the cabinet similarly to the manner in which the corresponding elements are arranged in the apparatus illustrated in Figure 1.

This form of the invention, like those described heretofore, provides low temperature refrigeragas then flows upwardly through the absorber in evaporation into the inert gas from a,v solution j of thetref'rigerant in the absorbent.

In accordance wtih" the present invention, a single refrigerating system is provided with a plurality of evaporators designed to operate at different temperature levels and is so constructed 1 and arranged as to supply refrigerating liquids having different characteristics to separate evaporators without the utilization oi'a complex refrigeratingiiuid.

The illustrated location of the rectifier is most convenient structurally asit allows the useof short direct connections to the boiler and low temperature evaporator. However; therectifler can be positioned above or on a level with the condenser thus placing the high temperature heat reiector at the top ofthe air flue. 1 The disclosed arrangement in which the inert gas traverses-the low temperature evaporatorbe- I :1. That method-of producing a' reirigerating eflect'. at a plurality of temperature levels which includes the'steps ofexpellingvapor from'a-so lution of refrigerant and an absorbent, liquefy ing such vapors toproduce liquids of different refrigerant concentration, andevaporating such liquids of diii'erent refrigerant concentration in separate evaporating zones. 1 l a 2. That improvement in the art of absorptionrefrigeration .which includes the steps-ofapplying heat to a solution of a refrigerant in an absorbent to expel vapors therefrom, rectifying such vapors by the extraction of heat therefrom in an amount suiiicient to liquefy substantiallyall vapot of the absorbent and to liquei'y a portion of the vapor of the refrigerant, liquefying the'residue vapor to produce refrigerant liquid which is substantially free of absorbent contacting the refrigerant liquid with an inert gas to produce a refrigerating eifect at a first temperature level, and contacting an inert gas with the liquid produced by rectification to produce refrigeration at a second temperature level.

tion by evaporation from substantially anhydrous refrigerant in a low temperature evaporator and provides higher temperature refrigeration by evaporation from a verystrong solution of refrigerant in the absorbent in a high temperature evaporator. All circulation of the refrigerant is by gravity as is the circulation of the inert gas and circulation of solution is achieved by a heat operated pump.

Thus, the present invention provides an absorption refrigerating apparatus in which low temperature refrigeration is achieved by evaporation of liquid refrigerant into the inert gas and in which high temperature is achieved by 3. That method of producing a refrigerating eil'ect ate. plurality of temperature levels which includes the steps of expelling vapor from a solution of refrigerant and an absorbent, liquefying such vapors to produce liquids of different refrig erant concentration, and evaporating such liquids of diiierent refrigerant concentration in separate evaporating zones in contact with a press sure equalizing medium which is inertwith re. spect to the refrigerant and the absorbent and while the pressure equalizing medium and all liquids of diflerent refrigerant concentrations are subjected to substantially the same total pressure.

4. That improvementin refrigerating systems of the type in which a'refrigersnt vapor is ex pelled fromsolution in an absorbent by the application of'heat, the refrigerant is separated from vapor of the absorbent by condensation of such absorbent vapor-and a portion of the refrigerant vapor-and the remaining vapor-is sense ratelyv condensed to liquid refrigerant whichincludes the steps of flowing an inert gas in contact with the aforesaid liquid refrigerant to produce a first refrigerating efifect thereafter flowing said inert gas into contact with thesaid condensed absorbent and the refrigerant condensed therewith; and thereafterpassingsaid inert gas a second liquid whichco'ntains the residue of the refrlgerantvapor condensed to liquid a first cooling unit, means for supplying said first liquid thereto for evaporation to produce a -refrigerating effect at a first temperature level, a

9. A'refrigerating apparatus comprising a solution circuit including a generator and an absorber, an inert gas circuit including "said absorber and first and secondcvapora'tors, a rectifier connected to receive vapors from sald'generator and to'dlscharge condensate into said firstfevap orator,- a condenser connected to :receive vapor from said-rectifier and to discharge condensate into said second evaporator, and means'in said inert gas circuit for propelling inert gas through one of said evaporators with a velocity sufiicient to distribute the condensate therethrough by the frictional dragof the inert gas. v 1 l 10. A refrigerating apparatus comprising a solution circuit including a generator and an absorber, an inert gas circuit includingsaid absccond cooling unit, and means for conveying" said second liquid into said secondflcooling unit for evaporation :to produce a refrigerating:- effect atasecond'temperature level;

6. In an absorption refrigerating mechanism,

1 means for expelling refrigerant vapor and absorbent vapor from a solution'of refrigerant and ab- 3 sorbent fractional condensing means for condensing saidvapors and for separately discharging a first liquid which contains the condensed absorbent and a portion'of-the condensed refrig .erant vapor andaisecond-liquid which "contains the residue of the refrigerant vapor condensed j. to liquid phase, a first cooling unitand a second cooling unit'connected to be subjected to the same total pressures, and means for supplying said first and second liquidsto said first and second cooling units, respectively, for evaporation therein whereby refrigeration is produced in said firstv and second cooling units at different temperature levels while said cooling unitsare ma'intained at the same total pressure.

7.. Inc refrigerating device, a cabinet including a mechanism compartment arranged to allow a flow of cooling air therethroughand an insulated compartment-divided into a freezing chamher and a storage chamber, a refrigerating mechanism comprising a freezing unit in said freezing chamber, a cooling unit in said storage chamber,' I means in said mechanism compartment for producing vapor of a refrigerant mixed with vapor of an absorbent, an air-cooled rectifier positioned to be contacted by cooling'air in said compartment,.means for conveying said vapors to said rectifier, means for conveying condensate formed in said rectifier into said cooling unit, an aireooled condenser positioned to be contacted by cooling air in said compartment connected to receive vapors not condensed in said rectifier and to discharge condensate into said freezing unit,

and means for removing vapor-sfrom said freezing and coolin u i 8. A refrigerating apparatus comprising a solution circuit including a generator and an absorber, an inert gas circuit including said absorber and first and second evaporators, a rectifier connected to receive vapors -from said generator and-to discharge condensate into said first evaporator, and a condenser connected to receive vapor from said rectifier and to discharge condensate into said second evaporator, said inert gas circuit being so arranged that inert gas flows sorber and first and second evaporators, said'fi'rst evaporator comprisingan upstanding conduit, said second evaporator comprising a substantially horizontal conduit; a rectifier connected to re-- ceive vapors fromsaid generator and to discharge condensate into the' upp r portion of sai first evaporator- 1oz gravityfiow therethrough, and a' condenser. connected to receive vapor from said rectifier and. to discharge condensate into said 1 secondevaporator; Y, a

. ILA refrigerating apparatus comprisinga solution circuit including ageneratori: and 'an air-- sorber. an inert gas circuit including'saidabsorber and first and second Ievaporators; said first and second evaporators comprising-substantially horizontal conduits,- a rectifier connected -to"re+ ceive vapor from said generator and-to'discharge condensate into said first evaporator; a condenser connected to receive vapor from said rectifier and to discharge condensate into said "sec0nd 'evap-' orator, and means in said inertgascircuit for' propelling inert gas through said evaporators with a. velocity sufilcient to sweep or'drag the condensate therethrough. I

l2. Anabsorption refrigeratingapparatus comprising a first evaporator having a slope sufilcient to cause liquid to fiow therethrough by'gravity, a

second evaporator positioned above said first I evaporator and also having a sicpe'sufiicientto cause liquid to flow ,therethrough by gravity,

means for supplying a refrigerating liquid to the upper portion of each of said evaporator-s, an ab sorber positioned below said evaporator-s, a gas conduit system for conveying lean inert gas from said absorber to said second evaporator. a gas conduit system for conveying inert gas from said second evaporator downwardly to thelower end of said first evaporator, and a gas conduit systern for conveying inert gas from the upper end of said first evaporator downwardly to said absorber whereby ilow of inert gas through said second evaporator is produced by the density differential between the warm lean 8'88 ascend ing from said absorber to said second evaporator and the cold partially enriched gas descending from said second evaporator to'said first evaporator and fiow of inert gas through said first evaporator is produced by the density differential between the gasfascending through said first evaporator and the colder richer gas descending from the upper portion of said first-evaporator to said absorber. 1

l3. Refrigerating apparatus comprising a freezing chamber, an evaporator positioned within said ri'reezing chamber comprising a substantially plane coil inclined slightly from the horizontal to. provide for gravity flow of refrigerant therethrough one of said evaporators counter to the direction of fiow of condensate therethrough;

- ature refrigerating chamber comprising through. an, coil comprising a plurality of elongated conduit portions serially connected at their ends, means for supplying refrigerant liquid to the upper portion of said coil, means for circulatlng. an inert gas through said coil, and a metallic plate over-lyingandthermally bondedto atileast the major area of one side of said coil,

said plate having a substantially horizontal upper face to; provide an untilted support for receptacles and the. like, certain of said conduit portions of i said coil underlying the central portion of said plate. z V I V r 14-. Refrigerating apparatus comprising a refrigerating compartment, means separatingsaid compartment into a low tempearture refrigerating chamber and a high temperature refrigerating chamber, an evaporator in said low tempera substantially plane coil inclined slightly from the horizontal to provide gravity flow of refrigerant therethrough, a-metallicheat conducting plate having a horizontalupper surface to provide a solution from whichlthe-vapor'wasexpeiled previously which includes the steps of rejecting heat for supplying; arefrigerant liquid to each of-said 1 coils, 'andameans for circulatingan inert --gas through each of said: coils *in contact with the refrigerantliquid supplied thereto. 1 Y

. l5. Ina-a refrigerating apparatus, a -cabinet structure having an insulated refrigerating charm" ber divided into:superposed high and lowtemperature refrigerating compartmentsfa mechanism compartment extending below said high and low temperature compartments and vertically along one wall of said chamben an absorption refrigerating mechanism associated with said cabinet comprising an evaporator in each of said refrigerating compartments, an air-cooled absorber lying in said mechanism compartment below said evaporators, means providing an inert gas circuit including said'evaporatpra and said absorber, and means for supplyingrefrigerant. liquid to the evaporator in said low temperature refrigerating compartment and for supplying a mixture of refrigerant liquid and absorption s0- lutionto the evaporator in said high temperature refrigerating compartment including air-;

cooled condensing means mounted in the vertically extending portion of said mechanism compartment.

16. In a refrigerating apparatus, a cabinet structure having an insulated refrigerating chamber divided into high and low temperature refrigerating compartments and a mechanism compartment structure extending below and along one wall of said refrigerating chamber, an absorption refrigerating mechanism comprising an evaporator in each of said refrigerating compartments, an absorber in said mechanism campartment, a generator in said mechanism compartment connected to said absorber in an absorbing solution circuit, means connecting said evaporators and said absorber in an inert gas circuit, condensing means positioned in said mechanism compartment adjacent one wall of said chamber and connected to receive vapors from said generator, said condensing means ineluding a first air-cooled portion which rejects heat at a high temperature and supplies condensate including liquid refrigerant and absorption solution to the evaporator in said high temperature refrigerating compartment, and a second air-cooled portion connected to receive va-' pors previously cooled in said first portion which rejects heat; at a lower temperature level than said first to; the evaporator in said frigerating compartment.) A 17. That improvement in absorption refrigerating'systems of the type involvingcexpulsion of vapors from a solution of a refrigerant in'an absorbent by the application of heat; liquefaction of. the vapors byextraction ofrheat therefrom into a cooling air, evaporation of. the liquid-into a gas which-is. inert with respect to the refrigerant and the absorbent, andabsorptionof the low temperature revapor produced by evaporation from the inert gas by ,contactlngthe inert gas and vapor with at a first temperaturelevel from vapors freshly expelled .from solution'to convert a portion of such. vapors to 'a-liquid comprising refrigerant and absorbent, rejecting heat at a second temper-.- avure level from vapor not liquefied at said first temperature level to convert. another portion of said vapor to liquid refrigerant; and producing re-' frigerating effects by, evaporating .liquids :produced atsaicl firstand secondtemperature levels into a movingbody 0 inert. gas-in separated evap- 101185 1 y- 131,; 11113. g 5 J, 8,, That improvement: in;. absorption refrigersting systems pf heit einvolving expulsion ,of vapors from .ajcolutionlofl, aaref ilgerant in anabsorbent ,bythe application ofsheat, liquefaction of-theyapors by 'extmqtion of heet therefrom intoa cooling air; ,evaporation of -the='liquid:-into a gas which is inert with respect-to the refrigerant and the absorbent, andaabsorption :of the vapor produced by *evaporation from the inert gas by contacting theinert gas and vapor with solution fronrwhlch the vapor was expelled previously which includes the steps of rejecting heat at a first temperature. level from vapors freshly expelled from solution, to convert a portion of uid produced at the other such vapor to .a liquid comprising refrigerant-and absorbent, rejecting heatat a second temperature level from vapor not liquefied ,at said first temperature level to convert another portion of said vapor to liquid refrigerant, producing a first refrigerating effect by contacting the liquid-prm duced at one of said'temrperature levels with a moving body of the inert gas, and producing a second refrigerating effect by contacting the liqof said temperature levels with said moving-body of inert gas.

19. In a refrigerating apparatus a cabinet having a refrigerating portion and a mechanism and heat rejecting compartment arranged for flow of cooling air therethrough, an absorption refrigerating mechanism associated with said cabinet comprising a plurality of cooling .units in heat portion and supplies refrigerant. liquid refrigerant liquids of different refriger meri s bein so arranged with respect to said generator that it receives a vapor mixture of refrigerant and absorbent and discharges a liquid consisting of refrigerant and absorbent and substantially pure refrigerant vapor, another of said condensing elements being arranged to receive substantially pure refrigerant vapor from said one condensing element and to discharge substantially pure liquid refrigerant, and means for conveying condensate from each of said condensin elements into an associated evaporator.

21. In a device of the character described a cabinetstructure including an insulated refrigerated chamber, an absorption refrigerating mechanism associated with said cabinet structure, said refrigerating mechanism including a. freezing evaporator in said refrigerated chamher, an air cooling evaporator in said refrigerated chamber, a generator, a rectifier connected to receive vapors from said generator and to supply a mixture of condensed refrigerant and condensed absorbent to said air cooling evaporator, and a condenser connected to receive vapor from said rectifier and to discharge refrigerant liquid into said freezing evaporator, said rectifier and said condenser being positioned exteriorly of said refrigerated chamber.

22. In a device of the character described, a cabinet structure including a refrigeration cham-- ber and a machinery compartment having an upstanding air fiue, an absorption refrigeration mechanism associated with said cabinet structure 1 including a generator, a rectifier, an absorber and 1 a condenser in said mechanism compartment, 9. i freezing evaporator positioned in the upper portion'of said refrigerated chamber, a space cooling evaporator mounted in said refrigerated chamber below said freezing evaporator, said condenser being of the air cooled type and positioned in the upper portion of said air duct, said rectifier bein of the air cooled type and positioned in said air duct beneath said condenser, means for conveying liquid refrigerant from said condenser to said freezing evaporator, means for conveying liquid refrigerant and condensed absorbent from said rectifier to said space cooling evaporator, means providing for circulation o an inert gas between said absorber and said evaporators, means providing for circulation of absorbent between said absorber and said generator, means for conducting vapor of refrigerant and absorbent from said generator to said rectifier, and means for conducting refrigerant vapor from said rectifier to said condenser.

23. That improvement in the art of refrigeration which includes the steps of expelling vap r of refrigerant and absorbent from a solution of refrigerant and an absorbent, condensing the va por of the absorbent and part of the refrigerant vapor to produce a first refrigerant liquid, evaporating the first refrigerant liquid to produce a first refrigerating effect, condensing the balance of the refrigerant vapor to produce a second refrigerant ,liquid, and evaporating the secondreiii frigerant liquid to produce a second refrigerating-- absorbent and a portion of the condensed refrigerant vapor and a second liquid which contains the residue'of the refrigerant vapor condensed to liquid phase, a first cooling unit, a second cooling unit, means for conveying said first and second liquidsto said first and second cooling units, respectively, means serially connecting said first and second cooling units for fiow of an inert gas therethrough, means for supplying an inert gas to one of said units and means for removing inert gas from the other of said units.

25. A refrigeratingapparatus comprising a solution circuit including a generator and an absorber, an inert gas circuit including an absorber and first and second evaporators, a rectifier connected to receive vapors from said generator and to discharge condensate into said first evaporator, and a condenser connected to receive vapor from said rectifier and to discharge condensate into said second evaporator.

26. A refrigerating apparatus comprising a solution circuit including a generator and an absorber, an inert gas circuit including an absorber and first and second evaporators, said first evaporator comprising an upstanding conduit, said second evaporator comprising a substantially horizontal conduit which is sloped slightly to provide for gravity flow of a liquid therethrough, a rectifier connected to receive vapor from said generator and to discharge condensate into the upper portion of said first evaporator, and a condenser connected to receive vapor from said rectifier and to dischar e condensate into the highest end of said second evaporator, said inert gas circuit being so arranged that inert gas flows through said evaporators in counterflow relationship with the condensate supplied thereto.

27. An absorption refrigerating apparatus comrising a first evaporator, a second evaporator, a generator, a rectifier connected to receive vapors from said generator and to discharge condensate into said first evaporator, a condenser connected to receive vapor from said rectifier and to discharge condensate into said second evaporator, an absorber connected in circuit with said generator for circulation of an absorbing solution, a gas heat exchanger having one pass connected to receive lean inert gas from said absorber and to discharge such lean inert gas into said second evaporator, said gas heat exchanger having a-second pass connected to receive rich inert gas from said second evaporator and to discharge such rich inert gas into said first evaporator.

ARNOLD D. SIEDLE.