US2250960A - Refrigeration - Google Patents

Description

July 29, 1941- w. H. K11-'ro REFRLGERATION Filed July 2o, 1938 '2 ASheetsy-,Sheet 2 lllllllllllllllllllllllll INVENToR TVilliam Hhiil ATTORNEY' Patented July 29, 1941 REFRIGERATION William H. Kitto, Canton, Ohio, assignor to The 'Hoover Company, North Canton, Ohio, a corporation of Ohio Application July 20, 1938, Serial' No. 220,193

15 Claims.

This invention relates to the art of refrigeration and more particularly to a novel control mechanism for a refrigerating system which will simultaneously control the path of flow of a plurality of uids within the system to alter the refrigerating effect.

According to the invention there is provided a sealed high pressure refrigerating system including a plurality of evaporating sections and a di- .version mechanism within the system whichis operated automatically to cause refrigeration `to be produced selectively in the various evaporator sections thereof.

'It is a further object of the invention to provide a refrigerating system in which ice is continuously formed in portions of a tank of Water which are in heat exchange relationship with various parts of the system. More specifically, it is an object of the invention to provide a system of the character above described in which ice blocks of a conventional size and shape are ticular part of the evaporator.

l It is a further object of the invention to provide a refrigerating system of the type utilizing an inert pressure equalizing medium which includes a means vsealed entirely within the system which is operative automatically to divert the path of flow of the liquid refrigerant and the inert gas in accordance with a predetermined condition existing outside said system Without passing any element through the walls of such system.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings, in which:

Figure l is a diagrammatic representation of the invention illustrating the manner in which it is applied to a continuous three-fluid absorption refrigerating system.

Figure 2 is a sectional elevational view illustrating the evaporator and freezing tank in detail.

Figure. 3 is a plan view,partly in section taken Figure 4 is a sectional elevational view of Figure 3 taken along the lines 4-6 thereof.

Figure 5 is a transverse sectional elevation taken along the lines 5-5 of Figure 3.

Figure 6 is a sectional elevational view of` a modified water tank structure.

Figure '7 is a plan view of the apparatus villustrated in Figure 6.

' Figure 8 illustrates a modified evaporator structure.v

The invention has been particularly designed for application to a continuous three-fluid absorption refrigerating system and it has been so illustrated, but the invention is not limited to the particular type of system disclosed as it may be applied to other types of systems.

Referring now to the drawings, and particularly to Figure 1 thereof, the refrigerating system comprises a boiler B, an analyzer D. an aircooled rectiiler'R, an air-cooled condenser C, an evaporator E, a gas heat exchanger H, atubular air-cooled absorber A, a solution reservoir S, a liquid heat exchanger L, and a circulating fan F which is driven by an electrical motor M. The above described elements are connected by a. plurality of conduits to form a complete refrigerating system including a number of gas and liquid circuits to which reference will be made in more detail hereinafter.

The above described refrigerating system will be charged with a suitable refrigerant, such as ammonia, a suitable absorbent, such as water, and a suitable inert pressure equalizing medium, such as nitrogen.

VThe boiler B may be heated in any suitable manner as by a gas burner or an electrical cartridge heater. The circulating motor M and the heater for the burner may be controlled in any suitable or desired manner in order to maintain the refrigerating system within the desired temperature limits.

The application of heat to the boiler B liberates refrigerant vapor from the refrigerant absorption from the upper portion of the analyzer D to the C by a conduit II which includes hthe air-cooled rectifier R. The rectifier causes condensation of any'vapor of absorption solution which may pass through the analyzer. In the condenser C the refrigerant vapor is liquefied by heat exchange with cooling air. The refrigerant so liquefied is conveyed from the condenser through a conduit I2 into the diversion chamber I1 of the evaporator E, which will be described more fully hereinafter.

lThe weak solution formed in the boiler is conveyed therefrom through the conduit I3, the liquid heat exchanger L, and the conduit I4 to the upper portion of the inclined absorber A. It is apparent that the upper portion of the absorber is above the liquid level normally prevailing in the boiler-analyzer system wherefore some means must be utilized in order to elevate the liquid upwardly to the absorber. For this purpose a small bleed conduit I6 is connected between the discharge conduit I8 of the circulating fan F and the conduit I4 below the liquid level normally prevailing in the boiler-analyzer system,

. whereby the weak solution is elevated into the absorber by gas lift action. In the absorber the Weak solution iiows downwardly in counterfiow relationship to an inert gas pressure equalizing medium flowing upwardly therethrough. The

absorption solution absorbs the refrigerant vapor content of the mixture and the heat of absorption is rejected to the air owing over the exterior of the absorber by the fins attached thereto. Strong solution is formed in the absorber by the absorption of refrigerant vapor. The strong solution is discharged into the bottom portion of a rich gas conduit I9 which communicates with the bottom portion'l of the absorber and opens into the solution reservoir S. -From the solution reservoir S the rich solution is conveyed by a conduit 2l, the liquid heat exchanger L, and a conduit 22 into the upper portion of the analyzer D, thus completing the absorption solution circuit.

The lean pressure equalizing medium formed in the absorber is conveyedfrom the upper end thereof to the suction inlet of the circulating fan F by a conduit 24. The inert gas is placed under pressure by the circulating fan and is conveyed through the conduit I8, the outer path of the gas heat exchanger H and a conduit into the bottom portion of the evaporator E which will be described more fully hereinafter. For the present it is sufficient to note that the pressure equalizing medium flows through the evaporator in which it is brought into contact with liquid refrigerant discharged from the condenser. The liquid refrigerant evaporates into'the pressure equalizing medium to produce refrigeration and the resulting strong rich `mixture of preure equalizing medium in refrigerant vapor is conveyed from the upper end of the evaporator through a conduit 21 into the gas heat exchanger H from which the rich gas is conveyed through the conduit I9 to the bottom portion of the absorber A. The `rich mixture flows upwardly through the absorber A incounterflow relationship to the absorption solution in the manner described heretofore.

oratorwill be denedspecifically. The lean gas inletconduit`2li` communicates ywith one end of a' U-s'haped` fast-freezing Icoil 39 and the other I upper portion of the tubular air-cooled condenser end of the coil communicates with an inclined rising conduit 3| which opens into the rear portion of the diversion chamber I1. The diversion chamber I1 communicates with a pair of spaced evaporator conduits 34 and 35 which are joined at their free ends by a cross connecting conduit 36. .The conduit 3E communicates with a lower rearwardly extending conduit 31 which opens into the rich gas discharge conduit 21. The conduits 34 and 35 are each provided with a plurality of heat conducting freezing pads 38 formed on the upper inner surface thereof. It will be noted that the conduit 36 extends downwardly from the ends of the conduits 34 and 35 to the level of the conduit 31 and then across the front of the evaporator where Ithe conduit 31 connects to its mid portion. The purpose of this will be explained hereinafter.

It is apparent from Figure 2 that the entire evaporator conduit structure is encased within an insulated housing 40 which includes an interior insulated freezing chamber 4I. The U-shaped conduit 30 lies in the bottom portion of the chamber 4I and carries a shelf 42 which forms the bottom wall of the chamber 4I. The conduit 31 extends along the top portion of the chamber 4I with which it is in heat transfer relationship. The conduits 34 and 35 are embedded in the insulation 44 in the -top portion of the casing 40 with the freezing pads 38 extending slightly beyond the`inclined sides of a troughshaped channel 45 formed in the top portion of the insulation 44. The trough-shaped channel 45 is adapted to receive a similarly shaped bottom portion 41 of a water tank 49 which rests in the channel 45 against the projecting portions of the freezing pads 38. The water tank may be removed from the pads 38 by lifting the same upwardly therefrom or by sliding the same' forwardly thereof, which is permittedA by reason of the fact that the conduit 36 is bent downwardly so as not to interfere with 'forward movement of the tank 49.

Thoseportions of the tank 49 immediately in contact with the freezing pads 38 are provided interiorly thereof with heat conducting metallic cup shaped elements 5I having outwardly tapered side walls which form moulds for freezing and terminate in slightly tapered spaced inlets 55 and 55, respectively. A cylindrical valve housing 51- receives the end portions of the conduits 3|, 34 and 35 and completely encases the inlets 55 and 56. The valve housing 51 and the end portions of the conduits 34 and 35 are encased within the diversion housing I1 which is constructed of a pair of complementary plate elementst and 6I.. The plates 99 and il entirely surround the end portions of the conduits 3|, 34 and 35 and the valve chamber51 and are welded or secured in any other suitable manner at their meeting edges. The forward\edge l2 of the plates '60 andfSI forms a rear stop abutment for the tank 49 to insure that the cup elements 5I will all be. positioned abo e the co' operating freezing plugs 38 on the conduits 34 and'35.

A valve plate member B4 is pivotally mounted on a pair of stub pintles 65 which are secured in opposite sidesof the valve chamber 51 and terminate in spaced relationships.l The end portion of the valve plate 64 is rounded as illustratedand is adapted to seal the outlet portions of either of the conduits 34 and 35. A

U-shaped actuating plate 66 is also mounted on the pintles 65 in the forward portion of the valve chamber 51. The plates 64 and 86 are each centrally out out; to form a receiving slot for a snap actuating spring 68 which is suitably attached to each lof the elements 64 and 66. U-shaped strap elements 69 are mounted on each side of the plate 66 bridging the spring receiving slot therein. The elements 69 extend out a sufficient distance on each side of the plate 66 so as not to interfere with the spring 68 in any position thereof. The strap elements 69 each abut small pins '1I which are slidably mounted in opposite sides of the valve chamber 51. Small. plugs 12 are suitably secured to the opposite side walls of the chamber 51 in order to provide bearing support for the pins 1I'.

A bi-metallic thermostatic element 15 is rigidly secured at 16 in any suitable manner to that portion of the conduit 35 mounted within the chamber I1 and rests against a heat conducting plug 11 on that portion of the conduit nearest the tank supporting part thereof. The bi-metallic thermostat 15 has a return bend portion 18 which abuts the freeend of an associated pin 1I. Similarly'y a bi-metallic element 80 provided with a free end portion 8I abuts the end portion of its associated pin 1I and' is rigidly attached to the conduit 34 at 82. The thermostat 80 abuts a heat conducting plug 83 which is attached to the conduit 34 adjacent the tank supporting portion thereof.

The liquid refrigerant `supply conduit I2 opens into the chamber I1 between and above the end portions 55 and 5B. of the`conduits`34 and 35 and directly infront of the point of connection between the chamber I1 and the riser conduitl 3I. In order to prevent liquid refrigerant discharged through the conduit I2 from flowing downwardly through the conduit 3i, a small dam 85' is mounted in the bottom portion thereof. Similarly, in order to prevent .liquid refrigerant from flowing into that portion'of the valve chamber 51 which houses the snap acting mechanism, a small dam 86 is erected z across the'l entrance evaporatoreonduits, thereby. to sur that-all liquid refrigerant discharged into the chamber IT. wilt 110W int.' one or the other offthesecqnduits. The" valve'plate, is cutaway 4) in order that 'it may freely 'ride over the upper portion ofthe dam'85. t Y

The operation of this form ofk the invention will now be` described.` When therefrigerating system is energized, liquid refrigerant will discharge through the conduit vI2 into 'the 'diversion chamber I1. Let it lbe assumed that the `apparatus has just been" placed in operation,

wherefore both thermostatic elements 15 and 89 will be .deformed to the position in which the mechanism will be in one position or the other and the bias of spring 68 will be the only overbalancing'force in ythe system. Assuming that the apparatus is in the position shown in Figure 3, the liquid refrigerant and inert gas will be unable to enter the end 55 of the conduit 34 for the reason that the same is blocked by the valve 64. Therefore, the liquid and gas flow only into the end 56 of the conduit 35. As the gas flows through this conduit in contact with the liquid, a portion of the 'liquid evaporates to produce refrigeration within the conduitv 35. Refrigeration so produced rapidly lowers the temperature of that body of water encased within the cups 5I which are in heat transfer relationship with the pads 38 on the conduit 35.

Th-e above described operation continues until such time as the cup 5I shall be. substantially lled'with ice whereupon the resistance to heat flow from the Water tank 49 to the conduit 35 will have reached a high value and the temperature within the conduit 35 will drop to a very low value. When this low temperature value is reached, the thermostat 15 will straighten out and assume a position such as that in which the thermostat-80 is illustrated in Fig. 3. When this occurs, the already expanded thermostat 80 will actuate the valve 64 to position to close off the inlet end of the conduit 35 and to open the e'nd of the conduit 34 to liquid and gas supply. The refrigeratng effect will now be shifted to the conduit 34 and refrigeration will be produced therein and will freeze ice cubesin exactly the manner described in connection with the conduit 35. While ice is being produced in the cup 5I in heat transfer relationship with the conduit 34, the previously frozen ice cubes in the cup 5I in heat transfer relationship with the conduit 35 slowly melt free thereof and float to the surface .of thewater contained in the tank 49. This continues until the temperature of the conduitr35 has raised sufciently high to cause the thermostat 15 a'gain to flex substantially to the position shown in Figure 3. This flexing ofthe thermostat 15 will have no effect on the snap-acting mechanism if the thermostat "88 is also in its flexed condition, indicating that ice blocks of the predetermined size. have not yet been-formed in those portions of the tank 5I in heattransfer relationship with the conduit 34.

' when the. ice blocks of the predetermined size y34, the thermostat'wswill straighten tothe posithereof., The height of the dams as and sus 5 5 such that their upper portionsl extend shove' theVV bottom Vpoi'ton 1f-"the" ehfdsfi" and 56]' of the have been formed in .those portions of the tank 4,9 in heat transfer relationship with the conduit tion indicated `inrfigure 3 and the snap-acting mechanism will. again actuated snap the valve s4 imo. the. vestida-shown in Afifi-gore ya to again produce refrigeration in. Athe i conduit 35.

. This alternate proeucngnof rfrigerduonin the A conduits 34 'and '35 continues as long as the iithermostat 15A is'illustrated in Figure 3, evidenc-' ing a demand forjrefrigeration. Under these conditions, both thermostatic elements are 0pposing each other wherefore the snap acting any liquid .redigeren not 'evaporated yin the conduits and 3,5'isdr`ained therefroininto the conduit M "andnows through that 'eondrut'to the rear end thereof.v 'Some 'vrefrigeration'v is produced within the conduit v31`and is utilized to refrigerate the chamber 4I which'is in heat exchange relationship with the conduit 31. The balance of the liquid refrigerant is drained from the gas outlet portion of the conduit 31 to the ther serve to refrigerate the low temperature storage and fast-freezing compartment 4|. The low temperature of this compartmentis assured by reason of the fact that the leanest gas is supplied thereto and also by reason of the fact that it is completely insulated.

The refrigerating compartment is cooled by the exposed walls of the tank 49 which have an extensive surface but which operate at a temperature above the freezing point of water. The air in the refrigerating compartment never contacts the evaporator which operates at a low temperature. By reason of this construction the refrigerating compartment is properly cooled but the humidity in that compartment is maintained at a reasonably high value to prevent objectionable de-hydration of foodstuffs stored-therein.

If desired a suitable cover may be provided for the tank 49.

In Figures 6 and 7 there is illustrated a modification of the water tank structure. In this modification the water tank 49 is shaped exactly as before, but the cup elements are replaced by ice freezing cups 90 which are interiorly divided by integral or thermally bonded cruciform grids 9| to form four ice mould compartments. The cups 90 and the grids 9| are preferably constructed from heat conducting material. The cruciform elements 9| are normal to the surface of the inclined portions 92 of the bottom of the tank 49. The outer walls of the cup elements 90 taper outwardly from the facing walls of the cruciform grids 9|. By reason of this construction each freezing cup forms four ice blocks and the tapered walls of each ice block permits the same to float freely away from the heat conducting walls of the ice mould when it has melted free thereof. The cup elements 9.0 are attached to thc walls 92 with a good thermal bond similar to that mentioned in connection with the cups 5| in order that heat may be abstracted from the water contained within these.-

cup elements through the cruciform grids 9| and through all walls of the cups 90. The exterior walls of the cups 90 are surrounded by a body of insulating material 93; for example, rubber. This tank is utilized exactly as is the tank 49 previously described. Though four ice compartments are illustrated in the cups 90, it is Within the purview of the invention to alter the design .of thesecups to produce other numbers and Ishapes of ice blocks.

In Figure 8 there is illustrated a modified form of the evaporator. Those portions thereof which .are identical withvpreviously described elements are given the same reference characters primed. This evaporator is designed and'intended to be inert gas is propelled through the evaporator E' with a velocity very much greater thanlthat prevailing in the evaporator E and the liquid refrigerant is swept through the evaporator conduit by the inert gas as it `is evaporating thereinto. kThe path 'of the liquid refrigerant is asfollows: Conduit U-shaped conduit 30', riser conduit 3|', diversion element conduits 34 or 35 depending upon the action of the diverter l1',

This evaporator differs from the preconduit 36', conduit 31. Any liquid refrigerant not evaporated in the various evaporator conduits and any foreign matter which may nd its way into the evaporator is simply swept therethrough, through the conduit 21 Iand through the gas heat exchanger into the strong absorption solution. A full explanation of the phenomen-a occurring in the evaporator E will be found in the co-pending application of Curtis C. Coons and William H. Kitto. Serial No. 220,189 led July 20, 1938. Due to the fact that the liquid refrigerant is led into the lowest portion of the evaporator, the condenser may extend substantially to the level thereof. This facilitates proper positioning of the evaporator in the cabinet and of the condenser in the usual cooling air flue.

. The evaporator described in Figure 8 operates to produce refrigeration exactly as that described in connection with Figure 1 with the following exceptions: The evaporator of Figure 8 lowers the temperature of the fast-freezing compartment before any refrigeration is produced in the conduits 34' and 35'. In this modification the temperature within the insulated chamber 4| is very quickly reduced to a low value after which only sufficient liquid evaporates in the conduit 30 to supply the heat loss t0 the chamber 40, and the remainder of the liquid is swept up into the conduits 34' or 35', as the case may be, in which it then evaporates to freeze ice cubes in the moulds mounted in the water tank.

The above disclosed apparatus provides a refrigerating system adapted to produce ice in -a selected one of a plurality of refrigerating zones under thel control of a thermostatic mechanism which is completely sealed within the refrigerating system and responds accurately to thermal conditions and refrigeration demands prevailing outside the system. This mechanism operates equally well whether the evaporator be of the gravity type, in which event the liquid and vgas flow counter to each other in certain portions of the evaporator and the liquid flows entirely by gravity, or of the type in which the liquid refrigerant is propelled through the evaporator by the inert gas stream.

In addition to the advantageous features above noted, the present system provides refrigeration for the food storage compartment under conditions which insure `safe refrigeration of that compartment while..maintaining..the humidity vention results from the fact that all portions of' the evaporator are either encased in the insulation for the compartment 40 or are positioned within that compartment which is sealed from ,the air within. the refrigerating compartment whereby it is impossible for the air vwithin the refrigerating compartment -to y contact the low temperature evaporating lelements and to deposit frost thereon. The combination of this feature anda high temperature box-cooling VWater tank completely eliminates the frost problem.

Iceis .formed in the bottom portion of a body of water by surrounding a portion of such body of Water of a predetermined shape with heat con-` ductingwalls which are in heat transfer relationship with a heat abstracting element and which are thermally insulated from thefwater not inicluded within the surrounded body of water.

-This device provides a very convenient and eflicient method of forming ice blocks of a predetermined conguration within a large body of water. Additionally, the freezing process is accelerated by reason of the fact that there are large-heat transfer surfaces in contact with the body of water to be frozen and an excellent heat transfer path is formed between large portions of the body of water to be frozen and the heat abstracting element. The arrangement of the freezing cups in the bottom of the tank 49 is advantageous because the cold water in the cups tendsto sink thereinto whereby the water in contact with the ice freezing portions of the tank 49 does not ow away therefrom when chilled.

'I'he capacity of the above described refrigerating` system will normally be a function of the refrigerating demand. This results from the fact that the refrigerating system will be controlled in accordance with the temperature of the refrigerating compartment, but the frequency of cycling will increase during periods of warm weather and will -decrease during periods of cool y weather, wherefore the quantity of ice produced y at any given time is a function of weather concilliquid refrigerant and a pressure equalizing medium to said evaporator sections, and refrigeration demand responsive means for diverting the liquid refrigerant and pressure equalizing medium into a selected evaporator section.

2. Refrigerating apparatus comprising a plurality of evaporator sections, means for supplying liquid refrigerant and a pressure equalizing medium to said evaporator sections, and refrigeration demand responsive means for diverting the pressure equalizing medium into a selected evaporator section.

3. Refrigerating apparatus comprising a` cooling medium supply means, a plurality of cooling units, a diversion element constructed and arrangedtodivert liquid refrigerant into a selected one of said cooling units, said diversion element being hermetically sealed within said refrigerating apparatus, and thermostatic means hermetically sealed within said apparatus for operating said diversion means.

4. An absorption refrigerating system of the type utilizing an inert pressure equalizing medium comprising means for supplying a liquid refrigerant, a plurality of-evaporating elements in said refrigerating system, means for propelling an inert pressure equalizing medium through said evaporating elements, and means sealed within such system for diverting inert gas and liquid refrigerant into a selected one of said evaporating elements.

5. An evaporator comprising a plurality of spaced evaporating elements, a control chamber valve means for directing the flow of refrigerant liquid and inert gas to a selected evaporating element.

6. Absorption refrigerating apparatus comprising a'solution circuit including a boiler and an absorber, a pressure equalizing medium circuit including an evaporator and said absorber, means for liquefying refrigerant vapor generated in said boiler and for supplying the refrigerant liquid to said evaporator, a water tank in heat exchange relationship with said evaporator at a plurality of points, and thermostatic control means sealed within said system for regulating the path of flow of inert gas and refrigerant liquid through said evaporator to restrict the production of refrigeration to selected portions of said tank in' accordance with refrigeration demands.

7. Absorption refrigerating apparatus comprising a solution circuit including a'boiler and anv absorber, a pressure equalizing medium circuit including an evaporator and said-absorber, said evaporator including a lower chamber refrigerating portion and an upper ice freezing portion,

means for circulating pressure equalizing medium upwardly through said evaporator, means for condensing refrigerant vapor generated in said boiler to the liquid state and for supplying :the liquid to the pressure equalizing medium inlet portion of said evaporator to be swept therethrough by said pressure equalizing medium as it is evaporatlng thereinto, and thermostatic control means sealed withinsaid system for regulating' the path of flow of inert gas and refrigerant liquid through said evaporator to restrict the proselected leg of said U-shaped conduit, and a thermostat arranged to be actuatedin response to the thermal condition of each leg of said U- shaped conduit for operating said valve means.

9. An evaporator comprising a U-shaped conduit, heat conducting projections formed on both legs of said conduit, a housing encasing the free ends of said U-shaped conduit, means for supplying a pressure equalizing medium and refrigerant to said housing, valve means in said housing constructed and arranged to direct'the pressure equalizing medium and refrigerant liquid into a selected leg of said U-shaped conduit,l and a pair of thermostats mounted within said housinglfor operating said valve means, each of said thermostats being arranged to be actuated in response to the thermal condition of an associated leg of said U-shaped conduit.

10. Refrigerating apparatus comprising a freezing chamber cooling unit, a pair of ice freezing cooling units serially connected -to said freezing chamber cooling unit, means for propelling a connected to each of said elements, means sealed ber, said control means including thermostatic r pressure equalizing medium through said cooling units, means for supplying a cooling medium to said freezing chamber cooling unit, a control' mechanism constructed andI arranged to divert pressure equalizing medium and cooling medium into a` selected ice freezing cooling unit, and means for draining cooling medium from each of p space cooling and freezing sections with a velocity sufficient to propel the refrigerant therethrough, and control means for preventing the inert gas and refrigerant from flowing through any but -a selected one of said freezing sections.

\ 12. In a device of the character described a v 2,250,980 said ice freezing cooling yunits into said freezing tainer element, the distance between the upper v edge of said container and the upper edge of said container for water constructed of heat conducting material having a lower wall and an upstanding peripheral wall, a wall element projecting inwardly of one of the walls of said container and y terminating below the top of said container to form the peripheral boundary of an ice moulding space includedwithin the said container) and a layer of heat insulating material on the exterior Ai'ace of said inwardly projecting wall element.

13. In combination a heat abstracting element,

a container element for water constructed of heat conducting material having a lower wall and an upstanding peripheral wall, said elements being in heat exchange relationship and being so constructed and arranged as to cause the freezing .etl'ect to be localized at a predetermined area of one of said walls, a wall element' projecting inwardly of the said. predetermined area of said one wall to form the peripheral boundary of an icev moulding space included within said coninwardly projecting wall being sufficient to allow ice blocks frozen in said space 'to float freely in said container and free of said inwardly projectinglwall when such ice blocks are melted free of the boundaries of said space.

14. An ice making device comprising a container for water constructed of heat conducting material having a lower wall and an upstanding peripheral wall, and a wall element projecting inwardly of one of the walls of said container and terminating below the top of said container to form the peripheral boundary of an ice moulding space included within the said container, said wall element and said plate element terminating below the top of said container a. distance suflicent to allow ice frozen within said ice moulding space to oat out of said space when such ice has melted free of the walls thereof.

15. An ice making device comprising a container for water constructed of heat conducting material having a lower wall and an upstanding peripheral wall, a wall element projecting inwardly of one of the walls of said container and terminating below the top of said container to form the top of said container a distance sumcient to allow ice frozen within said ice moulds to oat out of said moulds whemsuch ice has melted free of the walls thereof.

WILLIAM H. KITIO.

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