US2178870A - Continuous absorption refrigerating system - Google Patents

Description

Nov. 7, 1 939. c. c. COONS 2.178.876

CONTINUOUS ABSORPTION REFRIGERATING SYSTEM Filed Aug. a. 1936 4 Sheets-Sheet 1 C. C. CQONS CONTINUOUS ABSORPTION REFRIGERATING SYSTEM Nov. 7, 1939.

Filed Aug. 8, 1936 4 Sheets-Sheet 2 I II HI lLLl I l lllllll II lllllll ,lllllll II I l I] I I1 lllllll ll lllllll llllllIlll H lllllllll Illl [III Nov. 7, 1939. c. c. CQONS 2.178.870

CONTINUOUS ABSORPTION REFRIGERATING SYSTEM Filed Aug. 8, 1936 4 Sheets-Sheet 3 46 Q jzz plzfor':

NOV. 7, 1939. (Q coous 2,178.870

CONTINUOUS ABSORPTION REFRIGERATING SYSTEM Filed Aug. 8, 1936 .4 Sheets-Sheet 4 llllllllllllllllllllllllll Patented Nov. 7, 1939 2,178,870 CONTINUOUS ABSORPTION BEFRIGERAT- mo. SYSTEM Curtis C. Coons, North Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio Application August 8,

11 Claims.

This invention relates to continuous absorption refrigerating systems and more particularly to rectifiers and heat exchangers adapted to be used therein.

5 In the operation of a known type of continuous absorption refrigerating system using inert gas, approximately one fourth of the heat input to the boiler is discharged at the rectifier. The heat that is discharged from the rectifier to the cooling medium such as the air, in an air cooled absorption system is relatively high grade heat energy. If this heat is discharged to the cooling medium or to other than a part of the refrigerating system, the heat ratio of the refrigerator is 15 not high.

By means of the present invention, it is proposed to provide a continuous absorption-refug crating system in which this heat of rectification is discharged into the strong aqua or strong solution flowing from the absorber to the boiler, thereby improving the heat ratio.

It is preferable in accordance with the present invention to discharge the heat of rectification to the strong aqua instead of to the weak aqua due to the fact that the quantity of strong aqua fiowing is larger than the quantity of weak aqua by the amount of refrigerant absorbed in the absorber. Because of this it is not as practicalto transfer the heat of rectification to the weak aqua.

Accordingly it is one object of the present invention to effect a savings of heat and to bring about an improvement in the heat ratio of a continuous absorption refrigerating system by transferring heat from the rectifier'to the strong aqua flowing to the boiler.

It is still another object of the invention to provide an improved heat exchanger for transferringheat in the fluid leaving the boiler of a continuous absorption refrigerating system to fluid entering the boiler of that system.

It is still another object of the invention to provide an improved rectifier adapted for use in a continuous absorption refrigerating system.

for discharging heat of rectification to the strong aqua in the system. In all of the arrangements shown and described a single stage continuous absorption system using inert gas is illustrated but it is obvious that the rectifier and associated parts may be used in absorption systems which do not employ inert gas and also in systems in which two or more stages are employed. It will also be clear to those skilled in the art that the rectifier In the following description, means is described- 1936, Serial No. 94,934

' of one of the following figures may be used in other figures described-herein.

Various other objects and advantages reside in certain novel features of the arrangement and construction of parts as will be apparent from the following description taken in connection with the accompanying drawings in which,

Figure 1 is a diagram of a continuous absorption refrigerating system using inert gas and in which a rectifier constructed in accordance with the present invention is illustrated'in cross section, this arrangement showing one embodiment of the invention.

Figure 2 is a diagram of a modified form of continuous absorptionrefrigerating systems and il- 5 lustrating a further embodiment of the invention.

Figure 3 is a fragmentary, vertical cross sectional view of the rectifier of Figure 2 shown somewhat enlarged.

Figure 4 is a horizontal, cross sectional view of the rectifier shown in Figure 3, the view being taken on the line 4-4 thereof.

Figure 5 is a diagram of a continuous absorption refrigerating. system illustrating still another embodiment of the present invention and showing the rectifier and aportion of the analyzer of the system in vertical cross section.

Figure 6 is an enlarged fragmentary view in cross section of the rectifier assembly shown in Figure 5. l

Figure '7 is a horizontal cross-sectional view of the rectifier assembly of Figure 6 taken on the line 1-1 thereof.

. Figure 8 is a diagram of a continuous absorption refrigerating system illustrating still an- 35.

other embodiment of the invention and showing a horizontal rectifier in vertical cross section.

Figure 9 is an enlarged fragmentary vertical cross sectional view of the rectifier assembly shown in Figure 8.

Figure 10 is a transverse cross sectional view of the rectifier assembly shown in Figure 8, the view being taken on the line llllll thereof, and Figure 11 is a transverse cross sectional view of the rectifier of Figure 8, the view being taken on the line H,-ll thereof.

Referring to the drawings in detail, and first to the arrangement diagrammatically illustrated in Figure 1, it will be seen that a continuous absorption refrigerating system is there illustrated as consisting of a boiler B, a gas separation chamber S, the rectifier designated generally at R, a condenser C, an evaporator E and an absorber A,

these vessels being connected by a number of I conduits to form system.

In the arrangement of Figure 1, a gas lift pump II is employed for lifting absorption liquid from the boiler B into the gas separation chamber S. The refrigerant gas developed in the boiler system leaves the gas separation chamber S through the conduit l2 and enters the bottom of the rectifier proper. The rectifier consists of a vertically disposed cylinder [3 provided with a number of baiile plates I 4 therein. The cylinder I3 is surrounded by an outer jacket l5 through which liquid may be circulated to remove heat from the interior of the cylinder I3 and from the bafile plates l4 therein to effect therectification as will presently be described more in detail.

The refrigerant gas leaves the top of the rectifier I 3 through the conduit l6 which conveys it to the condenser C. After the refrigerant condenses in the condenser, it flows into the evaporator through the conduit II.

The evaporator E is connected to the absorber A by means of two inert gas conduits l8 and I9 which may be in heat exchange relation. The conduit l9 may connect the bottom of the evaporator to the top of the absorber and the conduit l8 may connect the top of the evaporator to the bottom of the absorber.

The conduit I 8 may have an inert gas circulator mounted therein as shown at 20 and this circulator may be an ordinary centrifugal fan driven by a hermetically sealed electric motor 2|.

the complete refrigerating A liquid conduit 22 connects the bottom of the gas separation chamber S to the top of the absorber. The bottom of the absorber is connected to the lower end of the jacket IS on the rectifier by means of the liquid conduit 23. The top of the jacket I5 is connected to a reservoir 24 by means of a liquid conduit 25 and the bottom of the reservoir 24 is connected to the boiler B by means of the liquid conduit 26.

It will be apparent that with this arrangement of liquid conduits, liquid may flow by gravity from the gas separation chamber S through the conduit 22 into the'top of the absorber and after trickling downwardly over baflle plates or the like within the absorber, flow by gravity through the conduit 23 upwardly through the jacket [5 and then downwardly through the liquid conduit 25 and the reservoir 24 back to the boiler through the conduit 26.

To prevent the accumulation of gas in the upper part of the jacket IS a reversely bent pipe 21 may connect the top of the jacket to the refrigerant conduit Hi.

The rectifier l3 must be provided with means for draining the liquid which collects therein.

is provided by the liquid drain conduit 28 connecting the lower portion of the conduit l2 to the reservoir 24.

It will be apparent from the above description that in the arrangement illustrated in Figure 1, the rectifier is located below the bottom of the absorber but above the normal level of the solution in the boiler B and in the reservoir 24. It will also be apparent that the strong aqua leaving the absorber through the conduit 23 is brought into heat exchange relation with the fluids in the rectifier l3 by means of the Jacket l5. It will also be clear that the pipes 23 and 22 may be in heat exchange relation and also that the pipe 26 which is connected to the bottom of the reservoir 24 may be in heat exchange relation with a portion of the pipe 22. The rel- 75 ative amounts of heat exchange area between the pipes 22 and 23 as compared with the amount of heat exchange area between the pipes 22 and 26 may be varied as desired to bring about the proper operation of the system.

The rectifier itself is essentially a beat exchanger and is part of the means for transferring heat from the fluids leaving the boiler to the strong aqua flowing to the boiler and it thus aids in the economy of heat.

While the arrangement illustrated in Figure 1 shows bafile plates within the rectifier cylinder l3, it is obvious that other filling material may be used.

The general features of the refrigerating system shown in Figure 1 are known to those skilled in the art and the operation of the system as a whole need not be described here in detail.

A modified form of the invention is shown in Figure 2 of the drawings. The general arrangement of the assembly may be the same as in Figure l and the parts which correspond are nects the top of the jacket formed by the upper portion of the cylinder l5 to the upper end of the conduit 29.

An important feature of the arrangement of Figure 2 and one which differs from the arrangement of Figure 1, results from the fact that the absorption liquid leaving the absorber A through the conduit into two streams by means of a solution divider 32. The solution divider may consist merely of a knife blade disposed below the lower end of the pipe 3|. One stream of solution flows from the dividing chamber 32 through the horizontal pipe 33 into the top of the cylinder I5 around the rectifier.

This stream is the only one which flows in heat exchange with the rectifier, the other stream passing downwardly through the conduit 34 and back to the boiler B. The stream of liquid which passes through the jacket formed by the cylinder l5 flows through the conduit 29 and from there into the reservoir 24 and drains back to the boiler through the conduit 36 connected, to the conduit 34. The conduit 34 may be in heat exchange relation with the conduit 36 to the conduit 34 may sired to obtain the best operation of the system.

It will be apparent that the rectifier assembly of Figure 2 causes a transfer of heat to the strong aqua from the refrigerant gas flowing from the gas separation chamber through the conduit 2 to the conduit l6 in a way similar to that described above in connection with Figure 1. One difference is to be noted, however, and that is that in the arrangement of Figure 2 the absorption liquid flows downwardly through the jacket I5 whereas in Figure 1 it flows upwardly therethrough. The strong aqua thus flows in counterfiow to the movement of vapors through the inner cylinder I 3 of the rectifier.

In the arrangement of Figures 1 and 2 a gas lift pump is employed for circulating the absorption liquid. Ihe present invention may be 35 into the conduit advantageously carried out where some motor or power driven liquid circulating means is employed and Figure 5 illustrates one way for accomplishing this. In this figure, the boiler B is shown provided with an analyzer chamber 31 which has a number of baflie plates therein as shown at 38. The top of the analyzer chamber is connected to the bottom of the rectifier cylinder I3 by means of a conduit 39. .The gases pass upwardly through the rectifier cylinder.l3 and flow through the conduit I6 into the condenser C as in the arrangement of Figure 1. The evaporator and absorber may be the same as described above in connection with Figure 1 and the parts which correspond are similarly designated. Absorption liquid is circulating between the boiler, the rectifier and the absorber by means of a liquid pump diagrammatically illustrated at 40 which is adapted to be driven by an' electric motor 4I. Liquid is supplied to the pump 40 through the cinduit 42 from a reservoir 43. The liquid is then lifted through the discharge conduit 44 of the pump into the top of the absorber and it then flows by gravity down through the absorber, then through the conduit 45 into the top of the jacket I5 surrounding the rectifier cylinder I3. The bottom of the jacket I5 is connected to some convenient point in the analyzer 3'Iby means of the conduit 46. After trickling downwardly over the baflie plates 38 in the analyzer, the liquid flows through the boiler B and back to the reservoir 43 through the conduit 41. Both the conduits 45 and 46 may be in heat exchange relation with the conduit 41 as in the somewhat similar arrangement in Figure 1. The heat transfer area between these 'conduits may be varied as desired.

The jacket I5 may be vented into the conduit I6 by means of, a pipe 21 and the rectifier cham- 'ber I3 may be drained into the conduit 46 by means of the small U pipe 48 connected to the lower end of the conduit 39.

The top of the reservoir 43 should be vented by.

means of a conduit 49 connected to the lower end of the inert gas conduit I8.

The operation of this system is similar to that described above in connection with Figure 1, the only difference being in the means for circulating the absorption liquid.

In both of the arrangements of Figures 1 and 2, the jacket I5 surrounding the rectifier cylinder I3 is merely a plain cylinder and is maintained full of strong aqua. In the arrangement of. Figure 5, on the other hand, the jacket I5 is provided with a number of bafile plates arranged in staggered relation, as best shown in Figure 6 and whichare marked 50. The baflle plates 50 aid in causing the transfer of heat from the vapors in the rectifier cylinder I3 to the aqua solution in the jacket I5.

In the design of-an absorption apparatus to include the special rectifier for permitting heat exchange between the hot vapors from the boiler and the strong aqua, the dimensions of the apparatus may be important if it is necessary to install the apparatus in a cabinet. In order to decrease the height to which the absorber must be elevated above the boiler to permit the use of the special heat exchange rectifier described above the use of a horizontal or slightly inclinedures Ste 11 inclusive.

In the arrangement'of Figure 8 a gas lift pump is employed for raising the absorption liquid as in the arrangement of Figure 1 and various other parts are the same as that in Figure 1 and are similarly designated.

A solution divider 32 is shown located below the absorber, as in the arrangement of. Figure 2 flows into the reservoir 24 and from there to the conduit 36 back to the boiler, the conduit 36 joining the conduit 34.

The rectifier shown in Figures 8, 9, 10, and 11 consists of a horizontal or slightly inclined cylinder 5| provided with a number of horizontally extending baflle plates 52. The baflie plates are preferably inclined in the same angle as the cylinder 5|. The trays may be supported on and held in spaced relations by means of a number of substantially vertically extending baflle plates 53 arranged in staggered relation. The baflle plates which extend down to the bottom of the cylinder 5| may be provided with small openings 54 to allow the passage of liquid therethrough. With this construction gas enters the cylinder 5I through the conduit I2 and passes upwardly and then downwardly over the trays 52, as directed by the baiile plates 53 until it leaves the cylinder 5I through the conduit I6 at the left hand end thereof, as viewed in Figure 8.

The trays 52 which pass horizontally, or substantially horizontally, through the baflle plates 53 may have slots therein for permitting the liquid to flow along each tray but in the arrangement shown a substantially tight fit is illustrated so that the liquid which collects upon the trays as the result of the rectification (which may be called the reflux solution) drips from the upper trays on to the lower one in between each of the battle plates 53 until it collects at the bottom of the vessel 5| and is drained through the holes 54 in the alternate baflle plates 53 and leaves the rectifier through the conduit 28 connected to the lower end of the vapor supply conduit I2.

It will be seen that with this construction a large area of contact for rectification is provided and at the same time a system for transferring heat to strong aqua is provided while utilizing a slight amount of vertical space.

From the above description, it will be clear that several different types of rectifiers adapted to be cooled by strong aqua in accordance with the present invention have been illustrated and described. In'all of these arrangements the rectifier is shown situated above the normal solution level in the boiler so that the rectifier can be drained by gravity flow'into the boiler. It is of course within the purview of the invention to locate the rectifier partly, or entirely, below the normal solution level in the boiler and use a pump to pumpthe strong aqua from the level of the rectifier into the boiler.

It will also be apparent to those skilled in the art that while only a few embodiments of the invention have been illustrated and described herein, various changes may be made in the arrangement and construction of parts without departing from the spirit of the invention or-the" scope of the annexed claims.

I claim: 1. In an absorption refrigerating system havm boiler to the absorber, then in heat transfer relation with the rectifier and then again in heat exchange relation with absorption solution flowingfrom the boiler to the absorber.

2. In an absorption refrigerating system hav- 15 ing a boiler, an absorber and means for circulat- 50 ment including a liquid divider for dividing the ing absorption liquid therebetween, the combination of a rectifier and means for transferring heat from the rectifier to absorption liquid flowing from the absorber to the boiler, the arrangeabsorption liquid leaving the absorber into two streams, one of which flows to the boiler and the other of which flows in heat transfer relation with the rectifier and then to the boiler.

35 3. In a continuous absorption refrigerating system having a boiler, an absorber and means for circulating absorption liquid therebetween, the combination of a rectifier and means for transferring heat from the rectifier to absorp- 30 tion liquid flowing from the absorber to the boiler,

both said rectifier and said heat transfer means including bafliing means positioned to cause the fluids within the rectifier and the absorption liquid to flow through tortuous passageways, the

5 arrangement being such that the liquid leaving the absorber flows by gravity in heat transfer relation with the rectifier and then by gravity to the boiler.

4. A rectifier assembly adapted for use in an absorption refrigerating system, said assembly consisting of a cylindrical vessel disposed subtantially in a horizontal position, a jacket surrounding said vessel, means for supplying vapors to the inner vessel and means for supplying liquid from a part of said refrigerating system to said jacket to take up heat from the vapors in said vessel, said vessel having a plurality of substantially horizontal trays therein and a plurality of substantially vertical bailie plates in spaced, staggered relation along said trays.

5. That improvement in an absorption refrigeration apparatus of the type having a boiler assembly, a condenser, an evaporator, and an absorber in circuit, and containing a refrigerant and an absorbent therefor, which comprises returning strong absorbent solution from the absorber to the boiler out of contact but in heat exchange relation with a mixture of hot refrigerant and absorbent vapor intermediate the boiler'and condenser, wherebyabsorbent vapor is condensed and its heat of condensation is given up to said strong absorbent solution, and conducting refrigerant vapor liberated from said strong absorb- -ent solution as a result of said heat transfer to the condenser.

6. An absorption refrigeration system comprising a. boiler, a condenser, an evaporator and an absorber connected in circuit, rectifying means in the circuit between the boiler and the condenser, means for returning at least part of the strong absorbent solution from the absorber to the boiler in heat exchange relation with said rectifying means, and means for venting said strong solution return means to a point intermediate the evaporator and the rectifying'device.

. 7. That method of separating absorbent vaporfromrefrigerant vapor produced in an absorption refrigeration apparatus which comprises passing said vapor mixture into heat exchange relation but out of contact with a strong solution of absorbent medium and refrigerant whereby the absorbent vapor is condensed and the heat of condensation is given up to the strong absorbent solution, and conducting any refrigerant vapor liberated from said strong absorbent solution into the refrigerant vapor from which the absorbent vapor has been removed.

8. An absorption refrigeration apparatus of the type comprising a boiler assembly, a rectifier assembly, a condenser, an evaporator, and an absorber in circuit, and containing a refrigerant, an absorbent therefor, said rectifier assembly comprising an elongated vessel positioned at an "angle to the horizontal and having one endthereof connected to the condenser and the other end connected to said boiler assembly, means forming a passageway in heat exchange relation with said vessel, said passageway being connected between said absorber and said boiler assembly in such manner that at least a part of the strong absorbent solu'tion flowing from the absorber tothe boiler passes therethrough, and arefrigerant vapor passageway from an upper partof said passageway aforesaid and said connection between the condenser and said rectifier assembly.

.9. That improvement in the art of rectification in absorption refrigeration apparatus of the type having a boiler assembly and an absorber connected in circuit, and containing a refrigerant in solution in an absorbent medium, comprising passing refrigerant and absorbent vapor liberated by the application of heat to the boiler assembly through a rectifier having a' tortuous passageway formed by baiiiing means therewithin, condensing said absorbent vapor by passing a stream of liquid at a lower tempera ture than said vapor in heat exchange relation but out of contact with said vapor in said rectifier, and subsequently returning, the liquid heated by the heat of condensation of said ab sorbent vapor to the boiler assembly, and simulj taneously conducting lean absorbent medium from said boiler to said absorber independently of said rectifier.

10. That method of producing refrigeration by means of an absorption refrigeration apparatus of the type having a boiler, a rectifier, a condenser, an evaporator and an absorber connected in circuit and containing a refrigerant, an absorbent therefor and a pressure equalizing medium, which method consists in liberating refrigerant vapor from the absorbent by the application of heat, condensing said vaporyevaporating the condensate so formed into the pressure equalizing medium to produce refrigeration, conducting weak absorbent and the mixture of refrigerant vapor and pressure equalizing .medium into intimate contact whereby the weak absorbent is-enriched by refrigerant, returning the pressure equalizing medium into the presence generating zone, passing lean solution directly and conducting refrigerant vapor liberated therefrom by reason of said preheating to the main stream of refrigerant vapor.

11. That method of producing refrigeration by means of an absorption refrigeration system having a boiler, rectifier, condenser, evaporator and absorber connected in circuit and containing a refrigerant, an absorbent medium therefor, and an inert gas, which method includes generating refrigerant vapor from rich solution in a to an absorption zone independently of an absorption vapor rectifying zone, and returning enriched absorption solution to said generating zone after passing the same in heat exchange relation but out of contact with the vapors emanating from said generating zone to condense absorption medium-vapor from said vapors and to preheat said enriched solution. 1

CURTIS C. COONS.

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