US1674830A - Refrigeration - Google Patents

Description

June 26, 119 28.

A. LENNING REFRIGERATION Filed March 20, 1928 5 Sheets-Sheet l June 26, 1928.

A. LEN NIN G REFRIGERATION Filed March 20, 1928 /0&

5 Sheets-Sheet 3 INV T013 June 26, 1928; 1574330 R A. LENNING REFRIGERATION Filed March 20 1928 5 Sheets-Shem v4 mama June as, 1928.

warren STATES 1,674,830 PATENT OFFICE.

ALVAR LENNING, F STOOKHOLM, SWEDEN, ASSIGNOB T0 ELECTROLUZ SERVEL GOR- scanner, or new YORK, 11. z,

A com oaa'rron or DELAWARE;

REFRIGERATION.

Application filed March 20, 1928, Serial No. 26,204, and in Germany July 21, 1827(- The present application is filed to replace m copending application Serial No. 159,-. 990 filed January 8, 1927, and Contains and claims the subject matter of said application Serial No. 159,990 and is to be considered as relating back to said application and as having all the rights incident thereto.

My invention relates to the art of refrigeration and is particularly concerned with ",.refrigeration systems of the type wherein a pressure equalizing medium is circulated between the evaporator and absorber, in the presence of which the refrigerant evaporates and wherein circulation of the equalizing gas between the evaporator and absorber is produced due to changes of s ecific gravity resulting from diffusion and a sorption. In systems ofthis character, particularly those operating under gravitational forces, there are limitations as to direction of circulation and the relation of circulation of one fluid to another. It is desirablethat-the equalizing gas should flow in counter-current to the refrigerant in the evaporator and in countercurrent to the absorption liquid in the absorber. This means that the mixture produred in the evaporator should leave the top of the evaporator and enter the bottom of the absorber whereas the poorer or liberated equalizing gas should leave the top of the absorber and enter the bottom of the evaporator. If the absorber and evaporator are merely combined in this manner the gas circulation would, under the influence of. gravity, and continue thus except as altered by the present invention. The present invention overcomes the natural difliculties abovepointed out and has for its object to produce the desired counterflow in both the eva rator and absorber under the influence o differences of specific weight of vertically extending bodies of fluid within the system. In accordance with the invention, circulation is started in the manner which gravitation tends to make 'it go and I provide means for reversing the flow in order-to obtain the desired result. p r

The invention will be explained in detail in connection with the accompanying drawings-o'n which: ig. 1 represents an absorption re rating system embodying my invention s own 'more or less tlcallly; V r Fig. 2 shows a modified eat exchanger v Referrin heat exchange relation with the M provided with start downwardly in the evaporator '19 communicates with absorber 27 at .a point for use in connection with the system of Fig hl. e remaining figures show an apparatus built and operated which embodles the present invention, Ofthese remaining 60 figures: Y I, v Fig. 3'shows the lower portion of an absorptlon system embodying the invention;

Fig. 4 shows an upper section of the same apparatus; v a

Figs. 3 and 4 together make one view when joined on the dash and dot lines A-A;

Fig. 5 is taken on the line 5 -5 of Fi 3; Fig. 6 is taken on the-line 66 of %ig. 4; and 7 Figs. 5 and 6 make one view when joined on lines BB. I more particularly to Fig. 1, reference 0 aracter 10 designates a generator which is divided by partition 11 into chambers 12' and 13. Formed within generator c 10 is a flue 14 within the lower part of which is placed a suitable source of heat such as a gas burner 15. Chamber 13 communicates with chamber 12 through a conduit 16. A conduit 17. leads from the upper part of chamber 12 in generator 10. A portion of conduit 17 passes through water jacket 18 and thence within conduit 19 to within 'the upper part of evaporator 20 which is in space to be copled. Evaporator 20 is disks 21 in which are holes 22 surrounded by raised rims 23. -Holes in adjacent disks are staggered so that adjacent holes are not directly in line with each other. A conduit 24 communicates with evaporator 20 at a point a short distance above thebottom. Conduit 24 leads to'heat exchan r shell 25 whichis arranged around con uit 19- A conduit 26 leads from shell 25 to the top of 7-; absorber 27. Absorber 27 is partly .sur-

rounded by cooling jacket 29 which is supplied with cooling water through a conduit 30 'and discharges water through conduit 31 into water jacket 18. The water.

is finally discharged through conduit 32. Absorber 27 is provided'with disks 33 simi" lar to disks 21 in evaporator 20. Conduit somewhatabo've the bottom and with evaporator 20 near the top. 1

A conduit 34 communicates with the bottom of absorbers?! and passes through heat exchanger 35 to a point a short distance bein low the top of chamber 13 in generator 10. A conduit 35 is connected to chamber 12 at a point somewhat above partition 11 and to one end of heat exchanger 36. A conduit 37 communicates with the other end of heat exchanger 36, makes one turn around aball the parts thereof are at approximately the same temperature and no circulation is taking place.

Contained within chambers 12 and 13 of generator 10 is a solution which consists of a refrigerant for instance ammonia, dissolved in an absorbing medium, for instance water. The application of heat from gas burner 15 causes the ammonia to leave the solution in chamber 12 andpass'upwardly in the form of a vapor. The ammonia vapor passes upwardly through that portion of conduit 17 which extends between generator 10 and water jacket 18 and herein any water vaporcarried by tlre ammonia is condensed and runs back to chamber 12. The dry ammonia vapor enters that portion of conduit 17 which is within Water jacket 18 and here the vapor is condensed to aliquid. The liquid ammonia passes through the remainder of conduit 17 to the upper part of evaporator 20. At the beginning of the operation of the apparatus, evaporator 20,

absorber 27, shell 25 and conduits 19,- 24 and 26 are full of a pressure equalizing gasinert with respect to ammonia, for instance hydrogen. Refrigeration in evaporator-20 is caused by the diffusion of the ammonia into the hydrogen. The mixture of ammonia and hydrogen in evaporator 20 has a greater specific weight than the hydrogen in conduit 19 and hence passes downwardly through evaporator 20, conduit 24, heat exchanger 25, upwardly through conduit 26 and downwardly through absorber 27 In absorber 27 the mixture of gaseous ammonia and hydrogen comes in contact with waterv which absorbs the ammonia and liberates the hydrogen. The heat given ofl by this absorption is carried away by the cooling water in cooling jacket ,29. The hydrogen passes "from absorber 27 upwardly through conduit 19 to evaporator 20.

The Water which contains ammonia in solut1on ,passes'out of the bottom of absorber 27, through conduit 34 to chamber 13 in generator 10. From chamber 13 it is elevated by means of theheat applied to chamber 13 through thermo-siphon pipe 16 to chamber 12 where the ammonia is driven out. of solumight be termed open and unobstructed com-.

munication Wherefore substantially the same gage pressiire exists throughout the system, varying only slightly in different parts due to heights of fluid columns and frictional flow resistances, while circulation is produced throughout all parts due to gravitation.

After the apparatus has operated in. vthe above described manner for .a short time, liquid ammonia will begin to pass through evaporator 20 without evaporating. This takes place because the apparatus is designed to operate with flow of hydrogen upwardly through the evaporator for obtaining complete diffusion. Hence during the period of downward flow of hydrogen, the ammonia is not completely diffused and evaporated. The liquid ammonia accumulates during the starting operation and some reaches the bottherein from absorber 27 to evaporator 20.,

The ammonia evaporates in the presence of the hydrogen. The mixture of ammonia and hydrogen isheavier than hydrogen and tends to pass downwardly through conduit 19. At first there is but a small amount of ammonia passing through conduit 38 to conduit 19 and its effect is to slightly retard the upward flow of hydrogen in conduit 19. The retardation ofthe flow of hydrogen to the evaporator, however. results in more liquid ammonia passing through the evaporator and condult 38 to conduit 19 which further retards the upward flow of hydrogen in conduit 19. This cumulative process proceeds until the upward flow of hydrogen in conduit 19 is entirely stopped. The relatively heavy mixture of ammonia and hydrogen now present in conduit 19 will flow downwardly therein to the bottom of absorber 27 The water absorbs the ammonia and the light hydrogen passes through conduit 26 and upwardly through heat exchanger 25, conduit 24 and evaporator 20. It passes through the evaporator in counterflow relation to the ammonia which tends to pass downwardly therethrough and thus complete tor 20, through conduit 19 to the bottom of absorber 27. Thus the direction of flow of gas between the absorber and evaporator has been reversed and a counterfiow relation-has been established between the hydrogen and liquid ammonia in the evaporator and between the gaseous mixture of ammonia and hydrogen and the water in the absorber. This counterflow relation gives better mixing and hence higher efficiency than flow in the same direction.

It will be noted that the evaporator is placed above the absorber and that thereis a considerable vertical extent to conduit 19 between the absorber and the point where conduit 38 is connected into the same. This vertical extent should be greater than the effective vertical extent of the evaporator in the evaporator-absorber cycle.

The accumulation of liquid ammonia during the starting operation is, in efiect, an accumulation of potential energy which, when released through .the lower opening of conduit- 38, is transformed into kinetic energy and causes circulation in reverse direction to that originally predetermined by natural gravitational force. It will be understood that oncecirculation has been begun in the reverse direction, that is upwardly through the evaporator and upwardly through the absorber, it will continue in this manner without the aid of conduit 38 and solely under the force produced by difierit will pass into conduit 19 where it will evaporate due to a higher temperature here than in the evaporator, and serve to cool the other gases in the heat exchanger. Thus the cooling effect of any excess ammonia is not lost.

If any 'li uid should be carried out of ah- I sorber 27, "t rough conduit 26, it will collect in the bottom of heat exchanger shell' 25. To allow this liquid to drain back into the absorber, a small capillary hole 40 is provided in conduit 19. This hole is so small that it will usually be closed by a capillary film of liquid which prevents the passage of any gas therethrough. I

In the alternative form of heat exchanger shown in. Fig. 2, additional heat exchange surface is provided by means of conduit 39 which is open to the space within shell 25. surrounding conduit 19 and extendsywithin;

conduit 19. I

- Referring to the apparatus shown in Figs. 3, 4, 5 and 6, the generator'is horizontal instead of vertical. It is indicated by reference character 10 as it corresponds to generator 10 of Fig. 1. Flue 14 passes through the generatorand a gas burner 15 is inserted in one end of the flue. A partition 5.0 divides the generatorinto a strong liquor chamber 51 and a weak liquor chamber 52.

Strong liquid from the absorber enters chamber 51 from conduit 53. The heat produces vapor which forces the liquid upwardly through riser pipe 54 (see Fig. 5) Riser pipe 54 extends upwardly from an extension chamber 55. Riser 'pipe 54 extends within a standpipe 56. The bottom of the standpipe is arranged to be disconnected from chamber 51 and from chamber 55 by means of a partition 57 through which riser pipe 54 extends. Holes 58 are provided to effect the production of alternate bodies of vapor 'and liquid in riser pipe 54 which causes outer chamber 63 surrounding standpipe 56.

It is to be considered that the portion of standpipe 56 which is adjacent to chamber 63 is part of the rectifier 60. In the rectifier, 7

due to liquid ammonia or other refrigerant in chamber 63, vapor of the absorption liquid is separated out when passing ballies 64 and flows back toward the generator. The substantially pure ammonia passes outof the upper open end of standpipe 56 and enters condenser conduit 65. The-condenser, designated generally by reference character 66, is composed of alternate ammonia and cooling water tubes which are soldered together. Cooling water supplied through conduit 67 and discharged through conduit 68 serves tocool and condense ammonia in condenser-66. The--condensed ammonia 'passes through conduit 69 which has been broken for purposes of illustration and en-' ters conduit 70.- This oonduit has a lower portion 71 which connects with chamber 63.

By this means liquid ammonia is present in chamber 63 and serves to rectify the 'vapor driven off .in the generator. Theheight of liquid ammonia is determined by the height of conduit 72 which admits liquid ammonia to the evaporator (see Fig. 6)- Liquid ammonia is also present in conduit 7 3 and chamber 74 surrounding acenter tube 75 of a vertical gas heat exchanger. The bottom of.

chamber 74 is determined by a partition76. Center tube 7 5 extends above the bottom of tube 72. Liquid ammonia accumulates'in chamber 74 at the start of operation until it overflows .into the evaporator through con-- duit 72. r

. The evaporator, indicated at) 80, contains 7 rounded b a casting or other heat transmit.-

ting mem er which may contain ice trays.

' f The mixture of hydrogen and ammonia passing out of the evaporator through conduit 82 passes into an outer chamber 83 of the vertical heat exchanger which is designated generally by reference character 100. From chamber 83 the mixture of gases passes through conduit 84 into the top of absorber 85 which also contains disk 86. The absorber is cooled by a cooling coil 87. From the bottom of the absorber, hydrogen passes upwardly through center tube 75 and to the top otthe heat exchanger and through conduit 72 back to the evaporator, v

The absorber is supplied with weak liquid supplied from generator chamber 52 thrcugh conduit 89, heatexchanger 90 and conduit 91'. Strong liquid 'flows from the absorber through conduit 92, through heat exchanger 90 and through conduit 53 into chamber 51.

Excess ammonia accumulates in the bot-- tom of the evaporator and in conduit 82 during the start of operation; When a certain amount has accumulated, it passes through member -101 which corresponds, in part, to conduit 38 of Fig. 1. Various arrangements may be made to accumulate and transfer the liquid- This member 101 is restricted at its receiving end 102. Furthermore, it rests above the bottom of conduit 82 to permit accumulation of the excess refrigerant. Member 101 extends to the surface of center tube 75 in order to deposit the accumulated liquid on the inner surface of center tube 75. When the accumulated ammonia passes through member 101, it increases the specific gravity of -gas in center tube 75 and reverses the directionof flow in the same manner as described in connection with Fig. 1 so that the flow is then downwardly through center tube 75, up through the absorber, through conduit 84,

V upwardly through chamber 83, through conduit 82, upwardly through the evaporator and back through conduit 72 to the center tube 75.

An inner tube 103 is provided in heat exchanger 100 which corresponds to tube 39 of Fig. 2.

Reference character 104 desi ates a vent pipe for preventing accumulation of hydro- The mixture of 2 gen in the upper part of conduit 70. This corresponds to conduit 41 of Fig. 1.

A hole 40 is provided at the lower end of chamber 83.

In applying this refrigerating apparatus to a cabinet the condenser is substantially at the top of the cabinet. Conduits 72 and 82 extend through the insulation-and evaporator 80 is in the food space to be cooled. The generator is either below the food space or set into the insulation at one side of the cabinet and the absorber is preferably set into the insulation. Thus the refrigerating apparatus preferably extends the fullheight of the cabinet.

While I have described various forms of my invention, it will be readily. understood that many arrangements are possible for carrying o t the invention.

What I c aim is: 1'. Refrigerating apparatus of the absorption type comprising an absorber, means to circulate absorption liquid through said sorption system including an evaporator and an absorber connected to afford a cycle of circulation between them which-consists in introducing liquid ammonia into the presence of hydrogen in the evaporator and producing movement of the resultant mixture ofammonia and hydrogen downwardly through the evaporator and to the absorber due to diflerence in specific weight of the mixture and hydrogen, separating the ammonia from the hydrogen in the absorber by absorption, completingthe cycle by returning the liberated hydrogen to the evaporator, accumulating undifi'used liquid ammonia,

and introducing the accumulated undiflused ammonia into the liberated' hydrogen returning to the evaporator and thus reversing the circulation.

3. That improvementin the art of refrigerating through the agency of an absorption system including an absorber and an evaporator connected by conduits to form a c 'cle including a plurality of. vertically exten ing branches and containing an inert gas, which consists in producing circulation downwardly in one branch and upwardly in a secorgd branch due to differences in specific gravity of fluids in the branches, accumulating liquid in said one branch and by- Leraceo passing said liquid into said second branch to reverse the clrculation.

.4. An absorption refrigeration system comprising an evaporator and an absorber. interconnected for circulation of fluid 'so arranged and containing such fluids that circulation having been begun in either direction through the evaporator and absorber, would continue in such direction due to forces generated within the system, while having a tendency to start in a given direction and means within said system for accumulating Potential energy during the starting. in said given direction and for reversing the flow by converting the accumulated otentialenergy into kinetic energy.

, '5. efrigerating apparatus of the absorption type comprising a generator containing refrigerant dissolved 'in absorption liquid, a condenser, an evaporator, 'an absorber situated below said evaporator, means for circulating absorption liquid between said generator and absorber, a conduit for conducting vaporous refrigerant from said generator'to said condenser, a conduit for conducting liquefied refrigerant from said condenser to the upper part of said evapory ator, conduits connecting the upper part of the absorber with the lower part of the evaporator and the upper part of the evapo rator with the lower part of the absorber for circulating a pressure equalizing gas between the evaporator and absorber and a bypass conduit connecting the lower part of the evaporator with the conduit extending between the upper part of the evaporator and the lower part of, the absorber for carrying liquid refrigerant thereinto fromv the evaporator.

6. Refrigerating apparatus of the absorption type comprising an absorber,'means to circulate absorption liquid through said absorber, an evaporator situated above said absorber, means to introduce liquid refrigerant into'the upper part of said evaporator,

a conduit connecting the lower part of the absorber with the upper part of the evalpo- .rator, a conduit connecting the upper part of the absorber with the lower part of the evaporator, said conduits being arranged in heat exchange relation and means for accumulating liquid refrigerant'and introducing the accumulated liquid refrigerant into the conduit connectingthe lower part of the absorber with the upper part of the evaporator.

7. That improvement in the art of refrigcrating through the agency of an absorption system including an' evaporator and an absorber connected to afford a cycle of 011- 'culation between them which consists in diffusing a refri erant into a ,pressure,

equalizing gas in t e evaporator, withdrawing the refrigerant from the equalizing gas by means of absorption liquid in the abaccumulating energy within the system toreverse the flow so that the equalizing gas will flow through the evaporator in counterflow to the refrigerant, from the evaporator to the absorber, through the abSOI'bGI TlII counterflow to the absorption liquid and from the absorber back to the evaporator due to said force.

8. That improvement in the art of refrigerating through the agency of an absorp-.

tion system including an evaporator and an absorber connected to afford a cycle of circulation between them which consists in introducing liquid refrigerant into the presence of an equalizing gas 1n the evaporator and producing movement of the resultant mixture of gases downwardly through the evaporator and into the absorber due to difference in'specific weight of the mixtureand the equalizing gas, separating the refrigerant from the equalizing gas in the absorber by absorption, returning the liberated equalizing gas to the evaporator, accumulating hquid refrigerant, and introducing the accumulated liquid refrigerant ,into the liberated equalizing gas returning to the evaporator and thus reversing the circulation.

9. In .an absorption refrigeration system, a generator, an evaporator, an absorber, liquefying means, the aforesaid arts of the system being interconnected for ow of fluid, said system including means for causing flow of fluid through the evaporator and means within the system for, automatically reversingthe said flow of fluid through the evaporator while the system is in operation.

10. In an absorption refrigeration system, a generator, an evaporator, an absorber, liquefying means, the aforesaid parts of the system being interconnected for flow of fluid, said system including means for causing flow of fiuidthrough the evaporator and means hermetically sealed within the system for automaticallyv reversing the said flow of fluid through the evaporator while the system is in operation. W

In testimony whereof I hereunto adix no i

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