USRE22153E - Refrigeration - Google Patents

Description

Aug. 4, 1942. A. LENNING 22,153

' REFRIGERATION v Original Filed Nov. 1. 1932 V 4 Shets-Sheet 1 INVENTOR BY Z- v ATTORNEY Aug. 4, 1942. A. LENNING 22,153

REFRIGERATION Original Filed Nov. 1, 1932 4 Sheets-Sheet 2 INVENTOR BY I M.

* ATIORNEY A. LENNING REFRIGERATION Aug. 4, 1942.

4 Sheets-Sheet 3 Original Filed Nov. 1, 1932' 225.2? wwvw wwmww m iNVENTOR an,

Aug. 4, 1942. A. LE NNING 22,153

REFRIGERATION Original Filed Nov. 1. 1932 4 Sheets Sheet 4 INVENTQR fi zmaz @ATTORNEY Reissued Aug. 4, 1942 REFRIGERATION Alvar Leaning, Stockholm, Sweden, assignor, by mesne assignments, to Serve], Inc., Dover, Del, a corporation of Delaware OriginalNo. 2,199,077, dated April 30, 1940, Serial No. 640,583, November 1, 1932. Application for reissue May 19, 1942, Serial No.443,606

50 Claims.

.This'application is a continuation in part of my copending application, Serial No. 506,591, filed Jan. 5, 1931. g I

My invention relates generally to refrigeration; more specifically to refrigeration systems.

of the absorption type; and still more particularly to systems employing a pressure compensating fluid.

Among the objects of my invention are: to provide an operable refrigerating system utilizing a plurality of refrigerants; to provide apcontact; to provide a system in which a pressure rise in circulating fluid is utilized to' promote circulation; to provide a system -in which circulation of both absorption liquid and pressure equalizing fluid is produced by a single factor, more particularly pressure in a local circuit be- V is connected 'to a con tween an evaporator and an absorber, and still fluids, more particularly of an absorber; to providea no-moving-part refrigeration system particularly adapted to operate at relatively high evaporator temperature; to provide an eflicient of the invention having a so-calledflooded evaporator;

3 is a similar view of another embodiment of my invention in which circulation between generator and absorber is'produced by a theme syphon; and i Fig.4 is a similar view of still another embodiment of my invention employing an intermitten't circulation between generator and absorber. l

generator II, which may be heated in any desired way, as by an electric heater ll inserted in the flue 12 extending through the generator. The generator is a vertically disposed cylindrical vessel. Connected to-the upper part of the generator is a conduit lI,'the upper end of which ll. Condenser It is cooled by water do through the tube Ii. It will be understoodtha other cooling means may be employed. The co denser tube and the water tube ii are side by side and wound into acoil,

In conduit ll aresomebaillesli 'and flanges I! cooled.

Condenser u a connected to achamber iii, the

condenser pipe projecting thereinto. A conduit It is connected to chamber It and extends vertically downward and is connected to an evaporator 20, which is a hollow cylindrical vessel with rounded ends and which contains distribpropane-ammonia system; to provide a system a refrigerant has condensed; and others as will hereinafter appear. a

Reference may be had to the accompanying -drawings forming part of this specification, and

of which:

Fig. 1 is a vertical eievational view. partly in section, showing one form of refrigeration systemembodying the invention in which vapor passing from the evaporator to the absorber causes circulation between the generator and the absorber;

Fig. 2 is a similar view of another embodiment uting discs or baiiies Il'having apertures therein. The apertures are surrounded by raised rims and those in adjacent plates are out of vertical alignment.

A conduit 22 is connected to the bottom of the evaporator and to an absorber N, which is also a cylindrical vessel with rounded ends. A transverse plate N is situated. within the absorber above the'connection of conduit 22 thereto, and this plate has a single centrally disposed aperture therethrough formed by a tube II. Above plate 24 and tube 2 is a number of baiiies 28 similar to the baiiies-in the evaporator.

' in baill'es II are also out of vertical alignment.

a conduit :1 extends downwardly from chamber i The apparatus shown in Fig. 1 -comprises a Any term of The apertures so and, like conduit I9, is

connected to the evaporator above baiiies 2l.-

A conduit 32 connects a low point of generator ID with the bottom of the absorber. extends, for part of its length, within a conduit 33. Conduit 33 connects a point in the absorber above baiiles 26 with a point in generator Ill above the connection of conduit 32 thereto. Where these conduits pass within each other they form a liquid heat exchanger.

Connected at the tops of chambers l3 and -30 are pipes 35 and 36. A cross-connection 31 is shutting qfi communication between the sameand cross-connection 31. Other valves may be Conduit 32 provided for charging or discharging or testing the apparatus such as the valve shown at the bottom of the absorber.

A coil 39 surrounds the absorber. Cooling water may pass through this coil, but when using and through conduit I3 to condenser II. The entrainment ofwater vapor with the expelled ammonia vapor is unavoidable and the rectifier is provided to remove this water vapor. The ammonia vapor passes into condenser 14 which is cooled by the cooling water flowing through pipe l5. This condenses the ammonia vapor and the liquid ammonia flows into chamber l8 and pipe l9.

At the same time, propane vapor passes upwardly through conduit 21 from the absorber and is condensed in condenser 28. The liquefied propane flows into chamber 30 and conduit 3|. Liquid columns of ammonia and propane, respectively, are built up in conduits l9 and 3| in the normal operation of the apparatus. Liquid ammonia and liquid propane enter the evaporator from conduits l3 and 3| and both these fluids evaporate, forming a gaseous mixture of propane vapor and ammonia vapor. This gaseousmixture flows downwardly through the evaporator and through conduit 22 into the absorber. The part of the absorber below plate 24 contains liquid. The gas flowing through conduit 22 passes upwardly through tube 25 and entrains absorption liquid therewith, moving the absorption oration process in the absorber, as will be furvessels and pipes to determine heights of liquid,

and a pressure gage may be connected to the top of .the evaporator or other suitable place.

The apparatus is charged with ammonia as a primary refrigeratingagent, propane as an auxiliary refrigerating agent and pressure compensating or equalizing fluid, and distilled water as an absorption liquid. The apparatus should be charged so that, in operation, the liquid level in the generator is above the point of connection of conduit 33 therewith, for example, at c, and so that the liquid level in the absorber is above the point of communication of conduit 33 therewith, for example, at a, and so that there is liquid in the pipes l3 and 3|. Allowance should be made for some liquid in each or the condensers.

' In the apparatus shown in the drawings which I have built and operated, the height of the absorber (outside dimension) is 10 inches. From this the dimensions of the rest of the apparatus can be determined since all the parts are of circular cross-section and the drawings are made to scale., In this apparatus,' when operating it, I have charged it with 1,700 cubic centimeters of ammonia solution'oi a specific gravity of .92 and about 100 cubic centimeters of liquid propane. It will be understood that the amount of fluid will vary for different sizes and shapes of apparatus and that these figures are merely illustrative. Enough propane should be supplied to fill the condenser 26, chamber 36 and pipe 3|. Aslight excess'may be placed in the apparatus without harming the operation since any excess not in transit will collect in the absorber as, for example,

vapor to be expelled irom solution. The am-- I monia vaporpasses upwardly in the generator liquid into the upper part of the absorber. In order to force gas through the tube 25 there must be a higher pressure in the evaporator than in the upper part of the absorber by an amount measured by the height of liquid or hydrostatic pressure in the absorber above the point of connection of conduit 22 thereto and the resistance to flow in the absorber. This higher pressure is maintained in the evaporator by the liquid columns in condlits l9 and 3|, and it is the head or hydrostatic pressure of these columns which forces the gas through the tube 25 and which thereby causes circulation of the absorption 'liquid. The columns are formed in order to create this pressure. They need not be artificially formed but form of themselves when heating and cooling are applied to the apparatus.

The liquid entering theabsorber-from the generator through pipe 32 is lean absorbent, weak in ammonia, and therefore the ammonia in the gaseous mixture is absorbed by this liquid. In the absorber, the propane becomes separated from the ammonia and passes'upwardly through conduit 21. The enriched ammonia solution flows through conduit 33 to the generator, where the ammonia is driven off. Weak absorption liquid passes through conduit 32 to the absorber. The pressure created in the evaporator by the liquid columns causes the gas mixture resulting from the complementary diffusion of the ammonia and propane in the evaporator to flow through pipe 22 and flow into liquid in the absorber and causes movement of the absorption liquid upwardly in the absorber and downwardly in the generator. It will be'noted that the connection ofpipe 22 with the absorber is well below l The Any propane not'in transitwill collect s liquid on the surtace of the ammonia solution in the absorber. Due to the heat liberated by the absorption of the ammonia, such propane can be brought to again evaporate and thus remove heat from the absorber which is not taken away therefrom by its external cooling.

Such heat removed from the absorber by evaporation of propane liquid collecting on the sur-' face of the ammonia solution in the absorber is transferred to the propane condenser and there given all to its cooling medium. The apparatus can also be operated by applying heat extemallyto the absorber. Such heating may be applied when starting the unit the first time in order to quickly bring about the proper distribution of fluid within, the system.

Evaporation of liquid ammonia and liquid propane in the evaporator produce refrigeration. The operation ofthis'embodiment is continuous, the flow through the various conduits being in one direction continuously.

This system differs from systems using hydrogen as a pressure equalizing medium in that the propane, which may be considered as replacing hydrogen as the inert gas into which the refrigerant evaporates, not alone provides the gaseous atmosphere into which ammonia evaporates, but also evaporates itself. Propane, acting as the auxiliary medium is partlygaseous and partly liquid in its circuit. In its gaseous state it is a dense gas relative to, for example, hydrogen, propane (CaHa) having a molecular weight of 44 compared to a molecular weight of 2 for hydrogen. The molecular weight of ammonia (NHa) is 17. Air, sometimes suggested as an inert gas for an ammonia diffusion system, is chiefly made up of oxygen having a molecular weight of 32 and nitrogen having a molecular weight of 28.

. This propane in its gaseous form is heavier or denser than ammonia or air.

'the evaporator.

The quantity charged into the apparatus may vary considerably since the level in the generator need not be fixed; nor need the level in the absorber be fixed. It is suflicient that the levels be somewhere between the communication of conduit 22 and theupper part of the respective vessels.

In order that the propane may pass-to the propane condenser and condense, the absorber should not be cooled to too great an extent and it need not be cooled at all. Heat is exchanged between the liquid flowing into the generator and thellquid flowing out of the generator. This provides a saving in the amount of heat applied. Conduit 31 equalizes the total pressure in thecondensers.

Another form of apparatus embodying the invention is shown in Fig.2. Like reference characters-are used to designate corresponding parts. One example of the fluids which I have used in this apparatus is 2-,300 cubic centimeters of ammonia solutionof a specific gravity of .905 or 26 per cent concentration and 3 ounces of propane. The operation of this apparatus is essentially the same as that'of Fig. 1. The condensers H and 28 are contained in separate tanks I! and 28.

but they may be contained in the same tank.

the evaporator instead of the bottom thereof;

. It will be seen that the apparatus of Fig. 2 has a flooded type of evaporator containing a pool or body of liquid refrigerant therein as distinguished from the dry type of evaporator of Fig. 1. it being understood, however, that liquid is held on the discs 2| of the evaporator of, Fig. 1.

In the apparatus of Fig. 2 I have provided 'met-' al wool 40 in the evaporator between perforated plates 4i therein. Metal wool 42 is also used in the absorber between perforated plates 43 therein. The conduit 22 is connected to the conduit 32. The introduction of the gas mixture into conduit 32 serves to lift liquid upwardly in the absorber and cause circulation in the same manner as that described in connection with Fig. 1.

Liquid columns are formed in the pipes I9 and 3|, a liquid column of ammonia being formed in pipe I! and of propane being formed in pipe 3|.- The head of these columns produces the excess pressure in the evaporator which forces the gaseous mixture of propane and ammonia vapor through conduit 22 and into conduit 32. This produces circulation upwardly in the absorber and downwardly in the generator.

A pool of liquid refrigerant is maintained in both the pressure equalizing fluid circuit, namely in evaporator 20, and in the absorbent circuit,

namely in the absorber. The excess pressure in the evaporator caused by the hydrostatic heads of liquid in pipes I! and II and reacting against the hydrostaticv pressure of the liquid column in the absorber causes refrigerant to flow. from theevaporator and into the pool of liquid in the absorber and thence in solution to the generator, and causes the absorbent to flow upwardly in the absorber to such an elevation that it can flow by gravity through pipe 32 to the generator and thence back to the absorber through pipe 32. This'drawing is likewise to scale. The height of the absorber in the cooling apparatus is 9 inches, from which thedimensions of the other parts can be sealed off.- v

Each of the apparatuses described is hermetically sealed and no force is transmitted through the metal of the apparatus. Circulation may be said to be produced by forces generated within the system;

Still another apparatus is shown in Again, like reference characters designate like parts. This apparatus also may be charged with ammonia, propane and water, although the invention is not limited to the use of these fluids. The generator ill comprises a hollow steel shell provided at its bottom end with an inverted cup 5|, which is welded or otherwise secured to an opening therein and which is adapted to receive an electric cartridge heating element H. Obviously. a gas flame or other heating means may be employed in place of the electric heater.

In normal operation, a solution of ammonia circulates through the generator. For conducting the solution into the generator a pipe ll extends through the lower end of' the generator proper and is connected to a small coil of tubing 52, which is wrapped around the inverted' cup 50. The upper end of the coil 52 is connected to a vertically extending pipe 53. which may be Fig. 3.

reversely'bent at its upper end as shown. -By this means when the current passes through the electric heater II, bubbles of ammonia gas are generated in the coil 52, and as they rise through the pipe 53 lift the solution into the generator I. Ammonia vapor passes, upwardly to pipe I! through a rectifier 54, which contains discs or baiiies 18 for removing water vapor which is driven off with the ammonia. The pipe J3 is connected to the ammonia condenser ll. As ammonia is driven off from solution in the generator, the weak solution is conducted away through the conduit 52.

The condensers .II and case be of any suitable construction. For purposes of illustration, they are shown as consisting of a small pipe coll inside of a larger one l5,

through which latter coil the water is adapted to circulate. The size of the condenser tubing in an apparatus built and operated by me in acam also in this be termed the ammonia cycle or main circuit, takes place from the generator l through the rectifier 54, pipe l3, condenser ll, evaporator 20, absorber 23', conduit thermosiphon coil 52 and pipe 53, back to the generator. Another 1 cycle, which may be called the propane cycle or cordance with this embodiment is approximately of an inch outside diameter with slightly less internal diameter. The condensers should be located a considerable distance above the evaporator so that fluid columns may be formed in the pipes l9 and 3|.

The evaporator, like the other parts, is made of steel and is cylindrical and contains lateral sets oi discs 2|. The upper discs are formed'with upstanding rims 5i and 51 to provide relatively deep cups for receiving liquid ammonia and propane from the conduits l9 and 3|. The flanges 51 are circular and provide overflow for the respective liquids onto the lower discs. The fluids evaporate from the respective discs in the evaporator and the evaporated mixture flows out from the evaporator through conduit 22. The evaporation in the evaporator abstracts heat from the surroundings, thus producing refrigeration. Any liquid which may have been supplied to the propane local circuit, takes place from the ab sorber 23 through the pipe 21, condenser 28, pipe 3|, evaporator and pipe 22, back to the absorber. The third-cycle, which may be called the solution cycle, takes place between the generator and the absorber, the circuit being from the generator through conduit 62, the outer coil SI of the liquid heat exchanger, conduit 59, the absorber 23, and back to the generator through the conduit 5|, coil 52, and pipe 53.

The operation of this apparatus will be clear from the above description and the description of operation given in connection with the previous embodiments. It will be noted particularly in this embodiment that theliquid flowing between the absorber and the generator is caused to circulate by means of a thermosiphon coil, wherefore the circulation is downwardly in the absorber, instead of upwardly as in the previous embodiments. The liquid level in the generator is maintained approximately at the top of the riser pipe 53 and preferably somewhat below the top of this pipe. The liquid level in the absorber evaporator and not vaporized, drains through the conduit 22. t

The absorber or separating vessel 23 consists oi a cylindrical drum closed at the ends. It may be cooled by circulating water through the coil 38 secured to the absorber shell. A perforated baffle plate 24 is situated near the lower end immediately above the point where the pipe 22 is connected to the absorber. Th upper end 0! the absorber is connected to the upper end of condenser 28 by means of pipe 21, this pipe being of larger diameter than that of the inner conduitof the condenser. The apparatus may be provided with any suitable charging devices, a valve 58 being shown for this purpose at the top of conduit 21.

For supplying absorption liquid to the absorber,

' a conduit 58 is connected to the absorber 'as shown. A regulating coil 60 may be placed around a part of conduit 29 through which water of predetermined temperature may be circulated, but this coil is not necessary to operation of the apparatus. The lower end of conduit 59 is connected to an outer jacket ll of a heat exchanger, the Jacket 6| surrounding the conduit 5|. The upper end or the Jacket il is connected'to conduit 82.

For conducting the absorption solution away iron: the absorber, the pipe 5|, which is connect-- it is condensed due to the coolingwater flowing in the jacket of this condenser. The liquid ammonia passes into the liquid column pipe' l9 and thus finds its Way to the evaporator. Propane vapor leaves the upper part of the absorber and passes through conduit 21 into the propane condenser 28. The propane flows downwardly through pipe 3| and into the evaporator. The propane and ammonia evaporate in the evapo-' rator and flow through conduit 22. into the absorber. The propane in part liquefles in the absorber and there is a pool of propane on the ammonia solution in the absorber. The apparatus may be operated without any coolin of the absorber, as described in connection with the other embodiments. It is necessary to maintain at least the upper portion of the absorber at a temperature higher than that of the condenser 28. This difference of temperature need only be suflicientto insure vaporization of propane in the absorber andcondensation in the condenser. Cooling water may be circulated through the a coil 39 though, as before stated, I have found that this is not necessary when operating at ordinary room temperature, in such case the temperature of the air, relative to the cooling water, being suflicient to maintain the necessary temperature difference. p

Since it is impossible to entirely separate fluids, there will be some ammonia gas in the propane I condenser and some propane gas in the ammonia condenser. These gase are readily carried out by the fluids in these pipes and I have found that the operation of the apparatus is not im- I paired on account or this condition.

In the apparatus operated by me from which Fig. 3 is reproduced, the external height of the absorber is 12 inches. The drawing is to scale, wherefore the dimensions of the various parts can be readily computed.

I have charged this apparatus with 4,300 cubic centimeters of ammonia solution of a specific gravity of .92 and 9 ounces of propane.

Obviously, the charging of the apparatus is merely a question of volumetric calculation. The apparatus may be purged of air by application ofheat or by vacuum.

In Fig. 4 I have shown still another form of apparatus which I have operated. Again, in this case like reference characters designate like parts. In this apparatus, as built, the height 'from the bottom of the generator to the top of the rectifier is 40% inches. The drawing is to scale, wherefore the dimensions of the parts can be readily determined: In this case the heat exchanger between the generator and the absorber is omitted and the pipe 33 is bent in the form of a trap to prevent passage of gas.

The general direction of circulation is the same as in Figs. 1 and 2, namely, upwardly in the absorber, and downwardly in the generator. I provide a tube 64 attached tothe side of the generator into which an electric heater may be j valve until the rate is satisfactory. In this case a I have made the pipe 32 of of an inch outside diameter, #17 age.

In operation of this apparatus I have found that the circulation sometimes reverses itself between the generator and the abs'orben. This reversal can assist in evaporating propane from the surface of the ammonia solution in the absorber, due to the warm solution passing through the pipe 33. Thus the pipe 33 constitutes a means for heating the upper part of the absorber for vaporizing the propane therein. The ammonia condenser is placed lower than the propane condenser on account of the difference in specific weight of propane and ammonia. It is desirable to so arrange the heights of the ammonia and propane condensers above the evaporator that the liquid columns will extend somewhat into the condensers. The liquid level in the evaporator standsat the level of pipe 22 and there may be an overflow of'liquid from the evaporator through the conduit 22. I

With this apparatus it is possibleto vaporize the liquid propane from the top of the absorber intermittently. the solution flowing first in one direction and then'the other.

I have operated this apparatus with 775 cubic centimeters ammonia solution of .93 specific gravity and 25 grams of propane.

It will be obvious that cabinets for cooling materials may be disposed around the evaporators of the various refrigerating apparatuses. Also, it will be understood that the data with respect to any of the embodiments is applicable to the other embodiments.

What I claim is:

1. Refrigerating apparatus adapted to produce cooling eil'ect by the evaporation of ammonia and. propane including. an evaporator in which said ammonia and propane may simultaneously evaporate, an absorber in which the ammonia may-be absorbed by an absorption liquid, means for cooling the lower portion of the absorber, and means for heating the upper. portion of the ab-' sorber to vaporize liquid propane therein.

2. Refrigerating apparatus adapted to produce I denser for said auxiliary refrigerant connected.

between said absorber and said evaporator and means for causing the auxiliary agent to pass through a cycle in which it is vaporized in the evaporator, liquefied in the'lower portion of the absorber, again vaporized in the upper portion of ,the absorber, again liquefied in the condenser and returned to the evaporator.

3. Refrigerating apparatus adapted to produce a cooling effect by the evaporation of a main refrigerant and an auxiliary refrigerant, said all-- paratus including an evaporator in which said refrigerants may evaporate, an absorber in which the main refrigerant is absorbed by an absorption liquid, a generator for expelling the main refrigerant from the absorption liquid, a condenser for said main refrigerant connected between said generator and said evaporator, a condenser for said auxiliary refrigerant connected between said absorber and said evaporator and means for causing the auxiliary agent to pass through a cycle in which it is vaporizedin the evaporator, liquefied in the lower portion of the absorber, again vaporized in the upper portion of the absorber, again liquefied in the condenser and returned to the evaporator, said means including a er and means for heating one portion and cooling another portion of said absorber.

5. In an absorption refrigerating system employing two refrigerants, an absorber, means for conducting a gaseous mixture of the refrigerants into said absorber, means for conducting a solvent for one of said refrigerants into said absorber and means for'maintaining the upper portion of said absorber at a higher temperature than the lower portion thereof.

6. In absorption refrigerating apparatus adapted to employ a main refrigerant and an auxiliary pressure equalizing agent, the combination with an absorber, a condenser, an evap orator and conduits connecting the same, of means for circulating said auxiliary agent between said-absorber, condenser and evaporator,

7. In refrigerating apparatus employing a main refrigerant and an auxiliary pressure equalizing 1 agent and having an evaporator and an absorber,

the method of circulating the auxiliary pressure equalizing agent between the absorber and the evaporator which consists in vaporizing the agent in the evaporator, liquefying the same in the absorber, applying heat to a portionof the absorber to vaporize the auxiliary agent and condensing the auxiliary agent at a level above the evaporator whereby it may flow back into the evaporator by gravity. 7

8. In an absorption refrigerating system employing two refrigerants, the combination of an evaporator wherein both of said. refrigerants may evaporate, a separating vessel, a conduit for conveying the vaporized refrigerants from said evaporator to said separating vessel, 8. generator, means for circulating an absorption solution between said generator and said separating vessel toconvey one'of said refrigerants to said generator, means for cooling a portion of said separating vessel to cause the other of said refrigerants to condense therein and form a layer on top of the absorption solution therein, means for heating said generator and a portion of said separating vessel to vaporize the refrigerants and means for condensing said refrigerants and returning them to said evaporator.

9. In a refrigerating system of the absorption type employing two refrigerants, means for causand again changed to a liquid phase.

10. In arefrigerating system employing a plurality of refrigerants, a vessel for separating said refrigerants'after they have become mixed and means for heating a portion of said vessel to vaporize one of said refrigerants.

11. In an absorption refrigerating system employing a plurality of refrigerants, a vessel for separating said refrigerants and means for heating a portion of said vessel to vaporize one of said refrigerants, said means consisting of a conduit adapted to convey an absorption solution to a portion of said vessel. i

12. The method of producing refrigeration including the steps of feeding a plurality of refrigerants in liquid phase into an evaporator, conducting the vaporized refrigerantsfrom the evaporator into a separating vessel, changing the refrigerants to more dense fluid phase in said vessel and separating the same by. gravity.

13. The method of producing refrigeration. in-

cluding the steps of feeding two different refrigerants in liquid phases into an evaporator, conducting the vaporized refrigerants from the evaporator into a separating vessel, changing the refrigerants to more dense fluid phase in said vessel, separating the same by gravity, vaporizing separating vessel, means for conducting a vaporsans mixture of said refrigerants into said vessel, means for circulating said solution through the separating vessel to thereby cause the solution to absorb one refrigerant so that the other may condense in said vessel and separate from the solution by gravity and means for returning the refrigerants so separated into the evaporator in liquid form.

15. In refrigerating apparatus, an externa heatedvessel, an externally unheated vessel, and means to intermittently circulate liquid between said vessels to transfer heat from the heated vessel to the unheated vessel to vaporize fluid in the unheated vessel.

16. In refrigerating apparatus of the type hav-.

ing an absorber, the improvement which consists of forming a pool of liquid refrigerant in the absorber, and introducing warm absorption liquid into the absorber to vaporize said refrigerant liquid.

l7. Absorption refrigerating apparatus of the kind employing a pressure compensating fluid including a generator, a condenser, an evaporator adapted to hold a pool of liquid, and an absorber, and conduits connecting the same to form a main circuit for refrigerant through generatorjconkind employing a pressure compensating fluid including a generator, a condenser, an evaporator A adapted to hold a pool'of liquid, and an absorber adapted to hold a pool of liquid, and conduits.-

connecting these-me to form a main circuit for refrigerant through generator, condenser, evaporator and absorber, a first local circuit for absorption liquid through generator and absorber, and a second local circuit for pressure compensatlng fluid through evaporator and absorber, said system including means to build up pressure in said second local circuit to cause pressure compensating fluid to recirculate therein and to pass through liquid of the pool in the evaporator and liquid ofthe pool in the absorber due to said pressure and to cause circulation of absorption liquid between the generator and the absorber due to said pressure.

l9. Absorption refrigerating apparatus of the kind employing a pressure compensating fluid including a generator, a condenser, an evaporator adapted to hold a poolof liquid, and an absorber adapted to hold a pool of liquid, and conduits connecting the-same to form a main circuit for refrigerant through generator, condenser, evaporator and absorber, a first local circuit for absorption liquid through generator and absorber, and aseco'nd local circuit for pressure compensating fluid through evaporator and absorber, said system including means .to build up sufficient pressure in said second local circuit to cause pressure compensating fluid to recirculate therein and to pass through liquid of the pool in the evaporator and liquid of the pool in said absorber due to said pressure, and additional means 22,153 to cause circulation between said generator and said absorber due to said pressure.

20. Absorption refrigerating apparatus of the kind employing a pressure compensating fluid including a generator, a condenser, an evaporator in which the bulk of refrigerant is evaporated, and an absorber, and conduits connecting the same to form a main circuit for refrigerant through generator, condenser, evaporator and absorber, a flrst local circuit for absorption liquid through generator and absorber, and .a second local circuit for pressure compensating fluid through evaporator and absorber, said system including means to build up pressure in said second local circuitagainst a liquid head to cause pressure compensating fluid to recirculate therein and means to cause circulation between the generator and absorber due to the pressure built up in said second local circuit, said second circult constituting the sole means for' conducting pressure compensating fluid from the evaporator to the absorber.

21. Absorption refrigerating apparatus of the kind employing a pressure compensatiag fluid including a generator, a condenser, an evaporator adapted to hold a pool of liquid, and an absorber, and conduits connecting the same to form a main circuit for refrigerant through generator, condenser, evaporator and absorber, a first local circuit for absorption liquid through generator and absorber, and a second local circuit for pressure compensating" fluid through evaporator and absorber, said system including means to build up suflicient pressure in fluid passing to the evaporator to cause such fluid to recirculate in said sec- 1 ond local circuit and pass through liquid of the pool in the evaporator and to cause circulationkind employing a pressure compensating fluid including a generator, a condenser, an evaporator adapted to hold a pool of liquid, and an absorber adapted to hold a pool of liquid, and conduits connecting the same to form a main circuit for refrigerantthrough generator, condenser, evaporator and absorber, a first local circuit for absorption liquid through generator and absorber, and a second local circuit for pressure compensating fluid through evaporator and absorber,

said system including means to build up suflicient pressure in fluid passing to the evaporator to cause such fluid to recirculate in said second local circuit and to pass through liquid of the pool in the evaporator and to pass'through liquid of the pool in the absorber and to cause circulation of absorption liquid between the generator and the absorber due to said presure.

23. Absorption refrigerating apparatus of thecluding means to build up pressure in fluid flowing in said second local circuit against a liquid column head to cause the same to recirculate in said second local circuit and means for producing circulation between the generator and the absorber due to said pressure.

24. A process of refrigerating which includes expelling a refrigerant from absorption liquid, condensing the refrigerant, evaporating the condensed'refrigerant in the presence of an auxiliary agent, conducting refrigerant and auxiliary agent into the presence of theebsorption liquid, re-,

turning the auxiliary agent to the placepf evaporation, raising thepressure of fluid flowing to" the place of evaporation, causing circulation of fluid between the place of evaporation and the .place of absorption due to said pressure while passing auxiliary agent both through liquid in I i the place of evaporation and the place of absorption, and causing circulation between the place of expulsion and the place of absorption due to said pressure.

25. In an absorption system of the kind employing a pressure compensating fluid including a generator, a condenser, an evaporator adapted to hold a pool of liquid, and 'an absorber, and conduits. connecting the same to form a main circuit for refrigerant through generator, condenser, evaporator and absorber, a first local circuit for an absorption liquid throughgenerator,

and absorber, and a second local circuit for pressure compensating fluid through evaporator and absorber, that improvement which consists in raising pressure of fluid in its path of flow in said second local circuit, causing pressure compensating fluid to pass upwardly through liquid in the evaporator due to said pressure and causing circulation of absorption liquid in said first local circuit due to said pressure.

26. In an absorption system of the kind employing a pressure compensating fluid including a generator, a condenser, an evaporator, and an absorber, and conduits connecting the same to form a main circuit for refrigerant through gen.-

erator, condenser, evaporator and absorber, a

first local circuit for an absorption liquid through generator and absorber, and a second local circuit for pressure compensating fluid through evaporator and absorber, that improvement which consists in raising pressure of fluid in its path of flow in said second local circuit, causing pressure compensating fluid to flow upwardly through liquid in said evaporator and said absorber due to said pressure and causing circulation of absorption liquid in said first local circuit due to said pressure.

27. In a continuous absorption refrigeration system of the kind employing a pressure equalizing fluid, the combination of a generator, an

absorber, an evaporator, conduits for circulating the pressure equalizing fluid between the pressure in one of said conduits to a total pressure above the pressure of gas in the evaporator and means for circulating absorption liquid between the generator and absorber and utilizing the raised pressure to promotethe liquid circulation.

28. In refrigeratingapparatus of the absorption type, a first element for producing a vapor mixture, a second element, means to conduct said vapor mixture to said second element, means to conduct absorption liquidto said second elenient, said second element constituting a condenser for one of the constituents of said vapor mixture, a separate condenser, a conduit connecting saidfseparate condenser with said second element, and means to re-evaporate the vapor constituent condensed in said second element.

29. The method of producing refrigerationincluding the steps of vaporizing a plurality of refrigerants in the presence oi each other, conevaporator and absorber, means for raising the liquid, absorbing one refrigerant and condensing another in the presence of the absorption liquid,

separating the condensed and absorbed refrigerants by gravity, expelling absorbed refrigerant from solution and condensing the same, and again conducting the refrigerants into the presence of each other.

31. In absorption refrigerating apparatus, an evaporator containing a plurality of'immiscible refrigerants, absorbing means containing liquid adapted to absorb one refrigerant and not another, means to cool said absorbing means to condense unabsorbed refrigerant, whereby. the

absorbed and condensed refrigerants are separated by gravity, means to remove the condensed and absorbed refrigerants fronrthe presence of each other, and means to return the refrigerants to the evaporator.

32. Absorption refrigerating apparatus comprising a generator, a condenser connected to said generator, an evaporator situated below said condenser, a conduit extendingvertically between said condenser and said evaporator for flow of liquid from said condenser into said evaporator having a.lower' opening within said evaporator 'at a lowerportion thereof and arranged to hold a column of liquid serving to maintain a higher pressure in said evaporator than in said condenser, air absorber connected to said evaporator, and means for circulating absorption liquid between the generator and absorber due to pressure exerted by said liquid column.

33. Absorption refrigerating apparatus comprising a generator, a condenser connected to said generator, an evaporator situated below said condenser, a conduit extendingvertically between said condenser, and said evaporator for flow of liquid from said condenser into said-evaporator having a lower opening within said evaporator at a lower portion thereof and arranged to hold a column of liquid serving to maintain a higher pressure in said evaporator than in said condenser, an absorber, means ,to circulate an aux- "iliary agent between and through the evaporator and absorber and means to circulate absorption liquid between and through the generator and absorber due to pressure exerted by said liquid column. e

34. In a refrigeration system of the absorption type including a generator and an absorber interconnected for the circulation of absorption, mSOl'lltiOl'i therebetween, and an evaporator con taining a body of liquid refrigerant, introducing an inert volatile fluid into said body 01' liquid refrigerant below the liquid level of the body. findflowing the resulting gas mixture by bubbling in s lution in said absorber to cause circulation of the solution between said absorber and generator and absorption of refrigerant vapor.

35. In an absorption refrigeration system, an

absorber comprising a closed vessehdivided into upper and lower chambers, a conduit within said vessel open at the lower end in said lower chamher, and at the upper end in said upper chamber, a. generator, a connection for liquid from said generator to the lower chamber of said absorber, a return conduit from the upper chamber of said absorber to said generator, an evaporator, and means for circulating gas from said evaporator upwardly through said conduit in the absorber.

36. In a method of refrigeration which includes distillation of refrigerant fluid from solu-' tion in an absorption liquid in a heated zone,. evaporation and diifusion of the distilled refrigerant fluid due to the presence of a comple mentary fluid, and absorption of refrigerant fluid out of the complementary fliud into absorption liquid withdrawn from said heated zone, that irn-' provement which consists in causing positive circulation of complementary fluid in bubble form within both refrigerant liquid and weakened abfluid. dissolved therein, liquefying the expelled refrigerant fluid, evaporating and diffusing the liquid refrigerant by presence of a complementary fluid, withdrawing absorption liquid from said heated zone, cooling the withdrawn absorption liquid, bubbling all of the gas formed by evaporation into the cooled absorption liquid to cause absorption of refrigerant fluid out of the gas into the absorption liquid and elevation of the resulting enriched absorption liquid to a level from which it may flow to said-heated zone by gravity.

38. The method of refrigeration which comprises, maintaining a body of liquid refrigerant, introducing an inert volatile fluid into said body below the liquid level of the body to cause evaporation and diffusion of refrigerant into the volatile fluid, flowing the resulting gas mixture by bubbling within a quantity of liquid absorbent,

'zone in a body having substantially the same surface level as that in said heated zone, maintaining a body of liquid refrigerant by distillation from absorption liquid in said heated zone, introducing a complementary fluid under pressure below the surface level of said body of refrigerant, circulating gaseous fluid from above the body of liquid refrigerant under sufficient pressure to cause it to bubble into absorption liquid from. said cooled zone after first flowing in contact with said liquid refrigerant, and utilizing the bubbling gas to raise absorption liquid to a level above that in said zones from which higher heat to rich absorbent medium to liberate a 'refrigerant for subsequent use in producing refrigeration,' removing and elevating the resultant lean absorbent to an elevated absorption zone by means of a stream of dense inert gas, condensing the refrigerant and evaporating the refrigerant in the presence of a dense inert gas.

41. In the method of operating an absorption refrigeration system of the type employing a refrigerant, an absorbent therefor, and a dense fluid inert with respect to the refrigerant com- P 8. applying'heat to rich absorbent to liberate the refrigerant in gaseous form, transforming the gaseous refrigerant to the liquid phase, permitting the liquid refrigerant to evaporate into said dense fluid to produce refrigeration, said method being characterized by the fact that the lean absorbent produced in the heating zone is elevated to an absorption zone above the heating zone by a propelled stream of refrigerantcarrying dense fluid in which absorption zone the refrigerant is absorbed. and the'enriched absorbent is returned to the heating zone by gravity and the dense fluid is returned to the evaporation zone.

42, That improvement in the art of refrigeration accomplished by the aid of a refrigerant medium, an absorbent therefor, and a dense pressure equalizing fluid, which consists in generating refrigerant gas from rich absorbent, raising impoverished absorbent to an elevated point by means of a pressure actuated stream of fluid iricluding dense pressure equalizing fluid, enriching said absorbent by bringing the same into intimate absorbing relation with refrigerant medium. and returning at least part of the enriched absorbent to the upper-portion of the liquid in a generating zone whereby the relatively cold engeneratorand absorber and a second local circuit for compensating fluid through absorber and evaporator, said system being operative to maintain a 'hedd imposing quantity of liquid in each of said local circuits, and said system including means to build up suihcient pressure in said sec-v ond local circuit to cause pressure compensating fluid to flow therein and to cause absorption liquid to flow in said first local circuit and to cause "compensating-fluid to pass through said head im posing liquid.

46. An absorption type refrigeration system ineluding a generator, an absorber, an evaporator adapted to hold a body of liquid refrigerant, a conduit for weakened absorption liquid from said generator to said absorber and arranged so that liquid is contained in said absorber and said generator at substantially the same surface level, means for circulating inert volatile fluid-between said evaporator and absorber against aliquid column head while introducing the inert fluid below the surface :level of liquid refrigerant in the riched absorbent acts to condense gaseous portions of the absorbent which may be passing off along with the refrigerant gas being generated.

43. That improvement in the art of refrigeration by the use of a three fluid absorption system which consists in generating a refrigerant gas for subsequent use in producing refrigeration from rich absorbent in a generating zone, conducting impoverished absorbent from the generating zone to an absorption zone thereabove by meansof a pressure actuated stream of fluid including a dense inertgas, enriching said absorbent by bringing the same into intimate absorbing relation with refrigerant gas, returning the enriched absorbent toa generating zone by gravity, condensing the refrigerant gas and evapo-.

rating the refrigerant in the presence of dense inert gas.

44. A method of refrigeration which includes maintaining a body of absorption liquid in a heated zone, conducting absorption liquid from said heated zone to a cooled zone, maintaining a body of liquid refrigerant by distillation from absorption liquid in said heated zone, producing refrigeration by complementary diffusion of refrigerant from said body and a complementary fluid while introducing the complementary fluid below the surface level of refrigerant liquid, flowing the combined gases resulting from said pro-' ductionof refrigeration in contact with absorption liquid from said cooled zone. and utilizing the combined gases to raise the absorption liquid to a level from which the liquid may flow by gravity to said heated zone.

45. Absorption refrigerating apparatus of the 7 kind employing a pressure compensating fluid including a generator. a condenser, an evaporator, an'absorber. and conduits connecting said parts to form a main circuit for refrigerant through g n rator, condenser, evaporator and absorber, a

evaporator and constructed and arranged so that gas formed in the evaporator is under sumcient eluding said pressure equalizing fluid, exposing said lean absorbent medium to refrigerant gas, thereafter separately applying heat to expel refrigerant gas from the absorbent medium, and then separately condensing the expelled refrigerant. i I

48. That improvement in the art of refrigeration by the use of a three fluid absorption sys-, tem of the type employing a refrigerant medium, an absorbent therefor, and a pressure equalizing fluid, and having a refrigerant medium circuit, an absorbent circuit. and a pressure equalizing fluid circuit, which improvement consists in creating a pressure difference reacting against hydrostatic pressure, maintaining a pool of liquid refrigerant in the pressure equalizing fluid circuit, maintaining a pool of absorption liquid in the absorbent circuit. and utilizing said pressure difference to circulate liquid refrigerant through at least a part of said refrigerant medium circuit, to introduce pressure equalizing fluid into the pool of liquid refrigerant below the surface level thereof, to introduce gaseous fluid into the pool of absorption liquid below the surface level thereof. and to circulate sa d absorbent through at least a part of said absorbent circuit.

49. That'improvement in the art of refrigera-' tion by the use of a three fluid absorption system of the type employing a refrigerant medium, an

absorbent therefor, and a pressure equalizing fluid, and having a refrigerant medium circuit, an absorbent circuit, and a pressure equalizing fluid circuit, which improvement consists in creating a pressure difference reacting against hydrostatic pressure, maintaining a pool of liquid refrigerant in the pressure equalizing fluid circuit, maintaining a pool of absorption liquid in the absorbent circuit, and utilizing said pressure flrst localcircuit for absorption liquid through i difl'erence to circulate liquid refrigerant through at least a part of said refrigerant medium circuit. to introduce ureequalizing fluid into the polo of liquid refrigerant below the surface level thereof, to introduce gaseous fluid into the pool oi absorption liquid below the surface level thereof, and to circulate said absorbent through at least a part of said absorbent circuit, said pressure difference being applied so as to circulate said refrigerant medium and, said absorbent simultaneously.

50. That improvement in the art of refrigeration b the use of a three fluid absorption systern of t type employing a refrigerant medium, w

an absorbent therefor, and a dense'pressure equalizing fluid, and having a refrigerant medium circuit, an absorbent circuit, and a pressure equalizing fluid circuit, which improvement consists in creating a pressure difference reacting against hydrostatic pressure, and utilizing said pressure diflerence to circulate liquid refrigerant through at least a part of said refrigerant medium circuit. and to circulate said absorbent through at least a part of said absorbent circuit,

the arrangement being such that said absorbent will flow through the remainder of said absorbent circuit by gravity. 1 ALVAR LENNING.

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