US2119864A - Fluid cooling apparatus and method - Google Patents

Description

June 7, 1938.- KLEUCKER 2,119,864

FLUID COOLING APPARATUS AND METHOD Filed Oct. 19, 1936 2 Sheets-Sheet l INVENTOE Geo/ e M K/eucken HTrO/EWEY June 7, 1938. G. M. KLEUCKER FLUID COOLING APPARATU AND METHOD 2 Sheets-Sheet 2 Filed Oct. 19, 1936 r 2 Tc K V MM. 6 v w 4 Patented June 7, 1938 v I Y I a UNITED STATES PATENT OFFICE 2,110,864 A,,M Z' IL,'IS'$M8 22 Claims. (CI. 62-12) This invention relates generally to fluid-coolvided in the bottom wall of shell I, is an opening ing apparatus and, more particularly, to appa-' 2, communicating with which is a shell 3 forming ratus adapted for the cooling of liquids, such asump B, the shell 3 being constructed either as beer, milk, water, and the like. integrally with the shell I or separately and 5 My present invention has for an object the rigidly welded thereto.

- provision of an apparatus and method for the l is a retaining collar or flange integrally cooling of fluids, such as beer, milk, water, and formed or welded rigidly to the shell I at its the like, in a sanitary and efllcient manner, and upperextremity, and a bell-shaped top member in such manner to utilize the maximum co-eflior wall 5 is provided with a companion flange cient of heat transfer. or collar. 6 adapted for interlocking engagement 10 My invention has for another object the prowith the flange 4 to provide a complete top clovision of an apparatus and method for the cool sureior the shell I. As shown in Figure 1, the ing of fluids and particularly liquids in which flange members! and Bare drawn together into the cooling medium or refrigerant is re-circu iluid and gas tight sealing engagement by means lated in liquid state either by means of differof suitable bolts I, and two packing glands I0 15 ential pressures without the intervention of a reand- II providing gas-tight entrance and exit, circulation pump,- by means of a mechanically respectively, to and from the shell I are disposed actuated circulating pump, or any other means on the bell-shaped top wall 5. Another packing whether used singly or combined. I gland I2 providing gas-tight entrance into the My invention has for stillanother object the lower part-of the shell I is disposed on the botprovision of an apparatus and method for the tom of the shell,"and a helical refrigerant precooling of fluids and liquids in which the heat cooling coil I3 is disposed within the shell I subexchanger or cooler is of a unitary construcstantlally as shown, the inlet end of the coil I3 tion that may be thoroughly cleaned between entering the shell I through the gland I0.- 5 cooling operations. A helical heat exchanger coil I4 is also dis- .25

My invention has for a further obiect-the posed within the shell I substantially as shown, provision ,of an apparatus and method for the the inlet end of coil I4 entering the shell I at cooling of fluids and more particularly liquids its lower end through the packing gland I2 and in which the heat exchanger is entirely leakthe outlet end of the coil I4 leaving the shell I 3o proof and which may be cleansed at high 'temthrough the packing gland II. I peratures without fearor danger of producing The coil I4 is disposed concentrically about leaks or permanent distortion therein. the pre-cooler coil I3 and is preferably ofcon- Other objects and advantages of the present timlmls e e ube wnstrllctlon, thereby invention will appear more fully from the followfording a readily cleanable one-piece surface ining detailed description, which, taken in conternally'of the evaporator. 1 5 nection with the accompanying drawings, ill Mounted above, and being substantially of thedisclose to those'skilled in the art the construesame diameter for registration with, the coil l4,

- tion and operation of a preferred form of the is an ar r r a t t u h Iii-p f a y present apparatus, in which drawings,- of U-shape in section, the trough I6 being formed 40 s Figure 1 is a cross-sectional elevational view on center line of its bottomorend'wall with 40 of an apparatus embodying my invention; an annular series of evenly spaced orifices I1 Figure 2 is a cross-sectional plan view of the each preferably ,of such selected dimensions to apparatus taken approximately on the line 2-2, permit he ir ulat d liq d refrigerant 0 fi Fi u e r the trough to a certain height, thereby building Figure 3 is a cross-sectional elevational view up some head on the bottom for constant even 45' 'of a portion of the apparatus illustrated in Figflow. Preferably also the trough sidewalls are. ure 1, showing, in part, a modified form of apps,- provided ,with depending extensions for confining ratus of my invention; and d the spraying refrigerant for coil. engagement, Figure 4 is across-sectional plan-view taken such,wall extensions following 'the contour of 5 approximately-on the line H, Figure 3. 'the upper member ofthe coil I4 and ,atizheir; 5o

-Referring now more in detail and by referlower margin being drw'g ev m 'ence characters to the drawings, the apparatus 1y spaced from the coil for correspon unigenerally designated A comprises a shell I, which form distribution ofthe refrigerant. It should is fabricated preferably from steel or other suitbe understood, however, that the present invenable material adapted to retain pressures. Protion is not limited to any. particular for is r I ing pipes '30 able distributor.

the uniform distribution of liquid refrigerant,

such as the trough above described, as other tion with a horizontally disposed pipe 20 extend-- ing outwardly through the wall of shell 3 to an expansion valve 2| connected on its other side to a pipe 22. The latter returns through the wall of the sump-casing 3 and is connected to a pressure nozzle 23, access to which is provided by a flanged opening 24 preferably located opposite a port-hole member 25.

As shown, an intake orifice 26 of a Venturi tube 21 is disposed opposite the pressure nozzle 23, the tube 2! being connected at its outlet orifice end to a refrigerant circulation pipe 28,. which extends upwardly angularly through the sump B and then vertically inside the main shell I to a distributor head 23.

A plurality of horizontal refrigerant distributextend radially outwardly from the distributor head 29 and terminate at points directly over the open top of the trough l6, suitable downwardly opening elbows 30? being provided at the extremities of the pipes 30 for directing the flow of the refrigerant downwardly therefrom and into the If a mechanically actuated pump is used, or other means for circulating the liquid refrigerant, a pre-cooling coil is not required. It will then only be necessary to feed the liquid refrigerant directly into the sump, means of a float control valve.

A main gas return line 3| projects through the top wall 5 to open shell I, the line 3| being connected at its other end to one side of a back pressure control valve 32 connected, in turn, at its other side to one side of a suction valve 33. On. its other side, the valve 33 is connected toasuction line 34, which, in turn, is connected to the low pressure or suction side of a suitable refrigeration system of conventional design (not shown). 7

An auxiliary safety gas return line 35 also projects at an end through the top wall 5 into shell I and is connected through a safety pressure relief valve 36 to the line 34 at a point beyond the suction stop valve 33.

The sump B is provided at its bottom with an oil drop leg 31, communicating with which is anoildrainvalve33,allasbestseeninFigure1.-

The sump B is also provided with a separate liquid refrigerant supply line 39 preferably floatcontrolled, by which the sump B is filled with liquid refrigerant to a level well above the intake orifice 26 of the Venturi tube 21. When the 'expansion valve 2| is opened, the suction created at the intake'orifice 26, as above described, will draw asubstantial quantity of liquid refrigerant through the tube 21 and intermingle it with the refrigerant coming from the jet out of .the pressure nozzle 23. And, in order to increase the heat transfer of the liquid refrigerant precoolmg coil l3, the coil |3 mayalso be provided with a liquid distributing trough or device simtrough Iii, or other suit- Preferably by at an end into the main ilar to the trough I6 associated with the heat exchanger coil l4.

It may be desirable under certain circumstances and conditions to provide a multi-stage expansion nozzle operation such as that shown in Figure 3. Such a multi-stage device comprises a vertical pipe 40, which corresponds to the vertical pipe l9, and is likewise connected to the bottom of the precooler coil l3 through theunion member I. The pipe 40 is also connected to a horizontal pipe 4|, which passes outwardly through the wall of the sump shell 3 and is connected to an expansion valve 42. The latter is connectedat its outlet side to a return horizontal pipe 43, which returns inwardly through the wall of the sump shell 3- and branches into two pressure nozzle supply lines 44 and 45, to which are connected two pressure nozzles 45 and 41, respectively, the pressure 'no zzle 45 having a Venturi tube 50 juxtaposed thereto. Access to pressure nozzle 46 is provided by a flanged opening 5|, as previously described in connection with Figure 1. Similarly, a porthole member 52 is provided adjacent the flanged opening 5|.

At its outlet orifice, the Venturi tube 50 enters into a vertical leg 53, which extends outwardly from the intake orifice 54 of a second Venturi tube 55. The pressure nozzle 41 extends upwardly through the vertical leg 53 to a point opposite the intake orifice 54 of the tube 55. It is preferable that the pressure nozzle 41 be located above the Point of entrance of the Venturi tube 50 into the leg 53, as shown.

Access to pressure nozzle 41 is provided by a flanged opening 55, and a port-hole member 51 is provided in the side of the sump shell 3 at a point adjacent the opening 56. The multi-stage expansion nozzle operation is not limited to the design shown in Figure 3, wherein the' second Venturi tube is connected at right angle to the first one. It may be preferable, and under certain conditions more desirable, to arrange the tubes in progressive series, so that they are in line with the flow in order to prevent friction losses, as the sure at the discharge of the recirculated refrigerant. The recirculating device previously described, both of the single effect as well as multistage eifect, located in sump B need not be an integral part of shell I, but may also be arranged as a separate part of the apparatus constituting the main evaporator, depending on conditions. An. oil drop leg 53 may also be provided in this embodiment in the same manner as described in connection with Figure l.

In operation, the liquid or fluid to be,c0oled enters the heat exchanger" coil l4 at the bottom thereof through the portion engaged in the packing gland l2, passes upwardly through the interior of the coil, and leaves the coil through the top portion thereof, which is engaged in the gland freon, and the like, enters the precooler coil 3 through the top portion thereof, which is enrefrigerant. The high pressure refrigerant passes outwardly from the expansion valve 2| through the pipe 22 to the pressure nozzle 23. The pressure nozzle 23 permits the refrigerant "45 main object of multi staging' is to build up pres- Liquid refrigerant, such as ammonia,

to exit therefrom in a high pressure jet, which enters into the'Venturi tube 21 at high velocity. The pressure and velocity of the refrigerant passing through the Venturi tube 21. is considerably higher than the pressure surrounding its intake orifice 26, such differential in pressures creating a 'suction through-the intake orifice 26 of the Venturi tube 21.

liquid refrigerant to a level well above the intake orifice 26 of the Venturi tube 21, the suction created at the orifice 26, as above described, will draw a substantial quantity of the liquid refrigerant through the Venturi tube 21 and intermingle the same with the refrigerant coming from the jet of the pressure nozzle 23.

The liquid to be cooled obviously gives up and transfers to the refrigerant its heat through the walls of the heat exchanger coil l4,- thereby evaporating a considerable quantity from the liquid refrigerant which is flowing down over the outer surface 'of the coil 14. Thus, the shelll becomes filled with gaseous refrigerant, which is drawn off from the top (if the main vessel through the main gas return line 3|. The unevaporated liquid refrigerant flows eventually into the sump B and is recirculated by means of the suction at the Venturi tube 21 up to the trough l6, whence it will again flow downwardly over the heat exchanger l4 and be partially evaporated in the course of pefforming its refrigeration function:

As all the high pressure liquid passing through the nozzle 23 of the jet has been subcooled in the liquid precooler coil l3, it is well deprived of flash gas and its action, when passing through the Venturi tube 21 mixed with the cold recirculated liquid through the suction orifice, is similar to that of solid water being handled. From the top member of coil I4, the liquid refrigerant runs downwardly in a large evenly distributed volume,

actually flooding each consecutive coil member,

partly evaporating into gas which is readily taken away at the top outlet of vessel am the suction of the compressor, while the surplus unevaporated liquid runs down into. sump B-to be recirculated.

The gaseous refrigerant caused by evaporation passes through the suction return line 3| to the back pressure, control valve 32, which is adjusted to such a setting that the requisite amount of back pressure and the corresponding temperature in the shell I will be maintained. From the back pressure control valve, the suction gas passes first through the stop valve and thence to the intake line 34 of a conventional, refrigeration machine, wherein the gas is ultimately condensed, and returned in a continuous cyclic manner to the precooler coil in liquid state.

In order to guard against undue pressure, an

auxiliary gas by-pass line 35 is provided, which conducts the gaseous refrigerant to the pressure release valve i6, set to relieve againstanyundue pressure above a prescribed maximum.

In order to maintain liquid refrigerant in the sump B constantly at a level substantially above the intake orifice of the Venturi tube 21, a liquid refrigerant supply line to the sump B is provided, which-preferably is controlled by a suitable conventional float valve mechanism. It is also obvious that proper insulation covering be placed about the outside of the shell I to prevent heat influx from the outside or room temperatures.

. In the event a greater recirculating head is required or greater pressure differentials are to be employed in the apparatus, it may be desirable to utilize a multi stage Venturi tube system such as that shown in Figure 3 or modified in progressive series, so that the tubes are in line with the flow, as previously described-- The operation of this multi-stage system is substantially similar to the operation of the single-stage Venturi tube I system above described.

orator type, the refrigerant inside must evaporate into gas in order to effect the required cooling. This gas necessarily must travel through the whole length of the coil to reach the suction outlet connection. For this reason, the co-efilcient of heat transfer is necessarily reduced whenever the refrigerant is inside of evaporating coils, since gas is a poor conductor ofheat. In the present invention, the liquid refrigerant isshowered copiously over the outside, setting free in a large vessel any vaporized liquid without impairing inany way the efficiency of the cooling surface on its rapid'downward travel, whereby a very high refrigerating efficiency is secured. The high efliciency obtained in the present invention is furthermore made 'possible by recirculating continuously cold liquid refrigerant over the cooling coil either in the manner previously described or by circulating pumps or any other means providing for the circulation of the liquid refrigerant over the outside of the heat exchange coil or coils in a copious manner as previously described.

As there exists in any refrigerating plant a pressure differential between the high or condenser-pressure and the low or suction-pressure, this condition is utilized in connection with a jet and Venturi tube for circulating or pumping cold liquid from a sump with precooled highpressure liquid through a jet over a heat'exchanger coil.

It will readily be understood that a large quantity of liquid refrigerant is flooded voluminously over the outer surface of the heat exchange coil without the slightest interference from any vaporized gas, as this emits immediately into the vessel or shell I, while' the whole heat exchange surface of coil l4 remains.c0vered with solid cold liquid on its rapid downward travel, thus giving. the effective cooling surface the highest efliciency possible. While previously comparison'has been made with evaporators of the pipe or coil type, employing the refrigerant inside of thepipe or .coil, another system of evaporator is that of the shell and tube type. In this evaporator, the liquid refrigerant is onthe outside of thetubes, which are closely assembled inside of a vessel. 'The shell of this evaporator is generally three-fourths filledwith liquid refrigerant, thus allowing gas space in the upper section of the cooler where suction connection is made to the compressor. During the process ofevaporatio n', gas bubbles of the plain expansion valve or flooded evapmay be connected to a are formed around the outside of the tubes, which eventually rise into the upper section of the cooler where the gas is taken away by the compressor suction. This forming of gas bubbles around the tubes continues as long as the cooler is in operation,- thus impairing the heat transfer, while through the tubes in the upper section of the cooler on account of not,

being submerged, the gas of the refrigerant necessarily becomes superheated.

In the present cooler, the gas enters thesuc tion to the compressor without any superheat but in saturated condition at a temperature corresponding to its back pressure. The foregoing description will also explain the extraordinary high heat transfer obtained by test. A e

In cooling liquids, such as milk or beer, it becomes necessary to shut down the cooling apparatus for permitting convenient cleansing of the interior of the heat exchanger coil H. On such occasions, the' valves to the compressor system are shut off and the drain valve 38 is opened to drain out all liquid refrigerant, which valve liquid refrigerant storage system of lower suction pressure or to another evaporator of lower back pressure to facilitate quick evacuation instead of pumping out, so that no liquid refrigerant is'lost. The pressure relief valve is provided as a special safety measure, so that any pressure within the main shell I will be released. It then is possible to pass hot cleaning or sterilizing liquids through the heat exchanger coils to cleanse and reno vate them. It is also possible to steam out the heat exchanger coil and scrub the same out with a suitable brush ball. Since the heat exchanger coil is of unitary construction and has a helical shape, there are no that the cleaning or therethrough rapidly the expansion which metal structure of return bends therein, so sterilizing solution will pass and quickly. Furthermore, normally takes place in a this character will not dis- 'tort the coil because of its helical shape, thus steam or hot cleaning and sterilizing solutions may be employed without danger of causing leaks or permanent distortion in the heat exchanger coil.

may be made in the Another of the many advantages of the cooler lies in its almost instantaneous application of refrigeration for starting and its immediate ceasing of the refrigerating effect after shutting down and evacuation of the cooler.

If the liquid refrigerant is circulated by a mechanically actuated pump, its suction connection is preferably made to the side of the oil drop leg 31, while the pump discharge -is connected to the distributor head 29. Pressure differential means for circulation may be'applied simultaneously with that of the pump, alternately or singly, as the case may be.

The apparatus and its many advantages will be .clearly understood scription, and it is obvious that numerous changes form, construction, arrangement, and combination of the several parts of the structure may be madeand substituted for those herein shown and described without de-.

from the foregoing deliquid refrigerant over the outer surface of the heat exchanger means for evaporating some of e refrigerant to produce cooling in the heat exchanger means,sump-forming means for collecting the unevaporated liquid refrigerant, and differential pressure control means disposed entirely within thesump-forming means for recirculating the unevaporated liquid refrigerant over the heat exchanger means.

2; A fluid cooling apparatus comprising heatexhanger means, means for passing liquid refrigerant over the outer surface of the heat ex-' passing liquid refrigerant over the outer surface of the heat exchanger means for evaporating some of the refrigerant to produce cooling in the heat exchanger means, sump-forming means for collecting the unevaporated liquid refrigerant,

and differential pressure control means disposed entirely within the sump-forming means including a high pressure nozzle and Venturi tube for recirculating the unevaporated liquid refriger ant over the heat exchanger means.

A fluid cooling apparatus comprising an' expansion chamber, a unitary one piece heat exchanger disposed within the expansion chamber,

- means for passing liquid refrigerant over the outer surface of the heat exchanger means for evaporating a quantity of refrigerant to produce cooling in the heat exchanger, a sump for collecting the unevaporated liquid refrigerant, and difl'erential pressure control means disposed within" the sump including a Venturi tube for recirculating the unevaporated liquid refrigerant over the heat exchanger means.

5. A fluid cooling apparatus comprising an expansion chamber, liquid refrigerant conduit means, heat exchanger means within the chamber, means connected to the conduit means for passing liquid refrigerant to the conduit means for passing liquid refrigerant over the outer sur face ofthe heat exchanger means for evaporating some of the refrigerant to produce cooling in the heat exchanger means, a sump for collecting the unevaporated liquid refrigerant, and pressure differential means disposed within the sump and co-operatively mociated with the conduit means for introducing unevaporated liquid refrigerant into the conduit means for recirculatlating liquid refrigerant over the surface of the heat exchanger.

8. A fluid cooling apparatus comprising an expansion chamber, a heat exchanger disposed within said chamber, refrigerant supply means for maintaining a flpw of liquid refrigerant over the outer surface of the heat exchanger, pressure control means operatively associated with the expansion chamber, said pressure control means and said refrigerant supply means being mutually adapted for relative adjustment for maintaining a predetermined gaseous liquid phase relationship for the refrigerant within the evaporator, pressure differential means for recirculating liquid refrigerant over the outer surface of the heat exchanger, meansefor. collecting the liquid refrigerant from the expansion chamber, and

differential pressure actuated means disposed entirely within the chamber for recirculating said collected liquid refrigerant over the heat exchanger means. Q

9. A fluid cooling apparatus comprising an expansion chamber, a heat exchanger disposed within said chamber, refrigerant supply means for maintaining a flow of liquid refrigerant over the outer surface of the heat exchanger, pressure control means operatively associated with the expansion chamber, said pressure control means and said refrigerant supply means being mutually adapted for relative adjustment for maintaining a predetermined gaseous liquid phase relationship 'for therefrigerant within the evaporator, pressure differential means for recirculating liquid refrigerant over the outer surfaceiof the heat exchanger, means for collecting the liquid refrigerant in the expansion chamber, and high pressure nozzle and Venturi tube means disposed entirely within the chamber for recirculating said collected 1iquid refrigerant over the heat exchanger means.

10. A fluid cooling apparatus comprising an expansion chamber, a helical coil heat exchanger disposed within said chamber, refrigerant supply means for maintaining a flow of liquid refrigerant over the outer surface of the heat exchanger, and pressure control means operatively mounted in the expansion chamber, said pressure control means and said refrigerant supply means being mutually adapted for relative adjustment for maintaininga. predetermined gaseous liquid phase relationship for therefrigerant within the evaporator.

11. A fluid cooling, apparatusicomprising an.

expansion chamber, a heat exchanger coil disposed within said chamber, refrigerant supply means for maintaining a flow of liquid refrigerant over the outer surface of the heat exchanger coil,

pressure control means operatively mounted in the expansion chamber, said pressure control means and said-refrigerant supply means being mutually adapted for relative adjustment for maintaining a predetermined gaseous liquid phase relationship for the refrigerant within the evaporator, and control means for evacuating the liquid refrigerant. from the expansion chamber.

12. A fluid cooling apparatus comprising a.

main shell, a sump shell disposed at the bottom of; and communicating with, the main shell, a

heat exchanger disposed within the main shell,

inlet means for introducingliquid refrigerant into the main shell, refrigerant pressure control means, a precooler coil connected at its one endto said inlet means and at its other end to the refrigerant pressure control means, and refrigerant distribution means connected to said pressure control means, said refrigerant distribution means including a trough for receiving a static head of liquid refrigerant and having a plurality of outlet orifices in the bottom thereof located in juxtaposition to the heat exchanger for directin a flow of liquid refrigerant over the outer surface of the heat exchanger. r

13. A fluid cooling apparatus comprising a main shell, a sump shell disposed at the bottom of, and communicating with, the main shell, a heat exchanger disposed within said main shell, inlet means for introducing liquid refrigerant into the main shell, refrigerant pressure control, means, a precooler coil connected at its one end to said inlet means and at its other end to the refrigerant pressure control means, refrigerant distribution means connected to said pressure control means, said refrigerant distribution means including an annular U-shaped trough for receiving a static head of liquid refrigerant, and having a plurality of outlet orifices so arranged as to provide an even distribution, and means cooperatively associated therewith for directing a flow of liquid refrigerant downwardly to the top A of the heat exchanger and over the outer surface thereof.

1 4. A fiuid' cooling apparatus comprising a main shell, a sump shell disposed at the bottom of, and communicating with, the main shell; a

position to the heat exchanger for directing a flow of liquid refrigerant over the outer surface of the heat exchanger, and auxiliary' liquid refrigerant supply means for introducing liquid refrigerant directly into the sump shell.

15. A fluid cooling apparatus comprising a. main shell," sump shell disposed at the bottom of, and communicating with, the main shell, 2.

heat exchanger disposed within the main shell,

inlet means for introducing liquid refrigerant into the main shell, refrigerant pressure controlmem, a precooler coil connected at its one end .to said inlet means and at its other end to the refrigerant pressure control means, refrigerant distribution means connected to said pressure control means, saidrefrigerant distribution means including a trough for receiving a static head-of 1 liquid refrigerant and having a plurality of outlet orifices in the bottom thereof located in juxtaposition to the heat exchanger for directing a flow of liquid refrigerant over the outer surface of the heat exchanger, auxiliary liquid refrigerant supply means for introducing liquid refrigerant directly into the sump shell, and means cooperatively associated with the last-named means for maintaining the supply of liquid in the sump shell constantly at a predetermined level.

16. A fluid cooling apparatus comprising a main shell, a sump shell disposed at the bottom of, and communicating with, the main shell, a helical heat exchanger disposed within the main shell, inlet means for introducing liquid refrigerant into the main shell, refrigerant pressure control means, a precooler coil connected at its one end to said inlet means and at its other end to the refrigerant pressure control means, said precooler coil being disposed concentrically inside the heat exchanger, and refrigerant distribution means connectedto said pressure control means, said refrigerant distribution means including a trough for receiving a static head of liquid refrigerant and having a plurality of outlet orifices in the bottom thereof located in juxtaposition to the directing a flow of liquid re-.

heat exchanger for frigerant over the changer.

17. A fluid cooling apparatus comprising an expansion chamber, heat exchanger means within the chamber, a refrigerant conduit extending into and terminating interiorly of the chamber, said conduit being provided at its terminal end with an orifice arranged for spraying refrigerant over the exterior of'the heat exchanger means, means in the chamber for collecting the excess refrigerant after passage thereof over the heat exchanger means, and pressure differential means within the chamber and forming a part of the drawing the'excess refrigerant into and redirecting the same over the heat exchanger means with incoming fresh refrigerant.

18. In a fluid cooling apparatus, an expansion chamber, a heat outer surface of the heat exthe formation of any substantial insulating gaseous layer between the film and the surface of the heat exchanger.

19. In a fluid cooling apparatus, an expansion chamber, a heat exchanger'disposed within said expansion chamber having relatively small displacement with respect to the expansion chamber, and refrigerant distributing means within said expansion chamber in juxtaposition to the heat exchanger means for flowing vaporizable liquid refrigerant over the outer surface of the heat exchanger means in a substantially uninterrupted and continuous film whereby to produce evaporation at the outer surface of the film and heat exchange through the body of the fllm.

20. In a fluidcooling apparatus, an expansion chamber, a heat exchanger disposed within said A heat exchanger means in a substantially unin-,

terrupted and continuous film whereby to produce evaporation at the outer surface of the film and heat exchange through the body of 'the film, means for collecting the excess refrigerant after it has passed over the heat exchanger, and means for returning said excess refrigerant to the distributing means for recirculation.

21. The method of cooling liquid comprising confining the liquid to be cooled in a walled con tainer, and flowing vaporizable liquid refrigerant over the entire heat exchange surfaces of the container in a continuous sheet, whereby to produce evaporation at the outer surface of the film and heat exchange through the body of the film.

. 22. The method of cooling liquid comprisingconfining the liquid to be cooled in a walled container, and flowing a vaporlzable refrigerant over the exterior surface of the container in sufficient the film.

GEORGE M. KLEUCKER.

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