US2941377A - Ice maker - Google Patents

Description

J. K. NELSON June 2-1, 1960 ICE MAKER v 2 Sheets-Sheet 1 Filed Feb. 6, 1956 INVENTOR June 21, 1960 J. K. NELSON ICE MAKER Filed Feb. 6, 1956 2 Sheets-Sheet 2 La-WAY VALVE INVENTOR L2 JAMES N ATTNEY United States Patent ICE MAKER James K. Nelson, Columbus, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 6, 1956, Ser. No. 563,490

6 Claims. (Cl. 62-73) This invention relates to refrigeration apparatus and more particularly to an improved method and apparatus for making ice in a domestic refrigerator.

This invention provides apparatus for freezing water into small ice pieces or blocks of a convenient size for use in a household, for removing the ice pieces from the freezing mold and for thereafter storing the ice pieces in a dry, readily usable condition. The apparatus performs all of these steps automatically and requires no supervision or manual effort from the user of the device. Because of the small size of the ice freezing apparatus, it is particularly suitable for installation in a domestic refrigerator, although the principles underlying the operation of the apparatus are usable in other ice producing equipment.

Thus, the principal object of this invention is the automatic production and storage of pieces of ice.

Another object of the invention is the provision of improved apparatus for automatically producing ice pieces.

Another object of this invention is the provision of an improved mold structure for ice making, which mold structure is deformable to effect ejection of ice from the mold.

A further object of this invention is the provision of improved means for removing ice pieces from the mold in which they are formed.

A still further object .of the invention is the provision of improved means and method of deforming an ice mold to effect the release and ejection of ice pieces from the mold.

Still another object of the invention is an improved method of removing water from ice pieces prior to the ice pieces being placed in a storage container to prevent the individual ice pieces from becoming stuck together while stored.

These and other objects are effected by the invention as will be apparent from the following description taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. l is a perspective view of a portion of a domestic refrigerator showing the ice making apparatus of this invention;

Fig. 2 is an enlarged plan view of the ice making mold of this invention with parts of the mold broken away to show the interior;

Fig. 3 is a further enlarged side elevational view of a portion of the ice making mold with parts broken away to show the interior. The line IIIIII in Fig. 2 shows generally how the parts are broken away in Fig. 3;

Fig. 4 is a vertical sectional view of the ice mold taken along the line IV-IV of Fig. 3;

Fig. 5 is a view similar to Fig. 4, but on an enlarged scale, and illustrating the action of the mold in ejecting an ice piece therefrom; and

Fig. 6 shows an electrical control circuit for the ice making apparatus with portions of the ice maker being shown diagrammatically.

Referring to Fig. 1 of the drawings, the numeral 11 designates generally an insulated refrigerator cabinet having a freezing unit 12 therein. As is apparent from the drawing, the cabinet 11 and the freezing unit 12 are both open at the front to permit access to their contents. While, in a domestic refrigerator, both the cabinet 11 and freezing unit 12 are provided with doors, these have been omitted from the drawings for the sake of clarity. It is also believed to be apparent that some type of refrigerating system must be provided for the refrigerator cabinet. Only the evaporator portion of the refrigerating system is illustrated, this being represented by the tubular conduits 13 through which low temperature refrigerant is circulated to cool the freezing unit 12 and the interior of the cabinet 11. Any conventional refrigerant circulating system of the types normally employed in a domestic refrigerator may be used to maintain the temperature of the freezing unit below 32 F. and preferably around 0 F.

Disposed within the confines of the freezing unit 12 are the principal components of the ice making and storage apparatus of this invention. These components are: an ice mold 14, a deflector 15 for guiding the movement of the ice pieces 16 ejected by the mold 14, a storage container 17 for receiving and storing the ice pieces 16, and a control 18. These components and their elements are described in detail below.

Ice mold The ice mold 14 of this invention is constructed in a novel manner to render it self-emptying, i.e., the parts making up the mold actually eject the ice pieces from the mold after they are formed.

Figs. 2, 3 and 4 show the construction of the mold 14, which includes an elongated, shallow housing 19 having a cover plate 20 which is provided with an irregularshaped opening 21 along its central portion to receive mold cups 22 in which the ice pieces 16 are formed. As shown, the mold cups 22 are preferably drawn from a single sheet 23 of thin, resilient material, such as beryllium copper, into which is also drawn troughs 24 connecting the cups 22 and providing for the flow of water therebetween. Each cup 22 is formed with conical side walls having considerable draft to facilitate the removal of the ice pieces therefrom. The bottom wall of each cup, designated 25, is given a concave configuration (as viewed from the top) in the forming process. The thinness of the sheet from which the cups 22 are formed (approximately .008 of an inch) permits the concave bottom wall 25 of each cup to be snapped back and forth from a concave to a convex shape, although the internal stresses tend to return the bottom wall 25 to the concave position illustrated in Figs. 3 and 4. The action of the bottom walls 25 of the cups 22 may be compared to the action of the bottom wall of a common oil can. This deformable wall portion 25 of each cup is utilized to eject ice from the cups 22 as will be explained more fully hereinafter.

The housing 19, cover plate 2%) and cup sheet 23 are brazed, welded, or otherwise bonded together at their mating edges to define a fluid-tight chamber 26 within the ice mold 14. As can be seen from the drawings, the cups 22 extend down into this chamber 26 with the exterior surface of the cup side and bottom walls being exposed to the contents of the chamber.

To refrigerate the mold 14 to freeze water in the cups 22, a serpentine extension 27 of the refrigerant conduit 13' is disposed within mold chamber 26 in close proximity to the cups 22. Some additional refrigerating effect is transferred to the mold 14 through a bracket 28 which supports the mold on the freezing unit 12 as shown in Fig. 1.

Also disposed within the mold chamber 26 is an electric heating element 29 employed to loosen ice in the heater 29 is brazed or otherwise sealed to the housing 19 at the point at which it enters the interior of the housing to insure fluid tightness of the mold 14.

Chamber 26, and secondary chamber 32 in communication with chamber 26, are charged with a volatile fluid These functions, are:

which performs two functions. (a) to assist in the transfer of heat between the mold cups 22 and the refrigerant conduit 27, and between the mold cups 2 2 and the heating element 29; and (b) provide a Working pressure within chamber 26 when heating element 29 is energized to deform the bottom wall 25 of each mold cup '22 to eject ice from the mold.

The volatile fluid in chambers 26 and 32 may be of the same type employed in the refrigerating system, i.e., any of the commonly used refrigerants such as dichlorodifluoromethane. Chambers 26 and 32 are charged with a sufficient quantity of this fluid to fill these chambers with liquid to a level substantially the same as the level of water being frozen in cups 22 when the mold 14 is at the average operating temperature of the freezing unit. This liquid line is identified in Figs. 3 and 4 of the drawings by the numeral 33. It will be noted that the refrigerant conduit is supported within chamber 126 by spacers 34 in such a position that an upper portion of the conduit is above this liquid line 33 and, hence, exposed to vaporous fluid. This arrangement speeds the transfer of heat from the cups 22 to the refrigerant conduit 27 during the period when water is being frozen in cups 22 by utilizing the fluid in chamber 26 as a secondary refrigerating medium. It can be readily appreciated that fluid vaporized around cups 22 by the heat from water within the cups will rise to the upper portion of chamber 26 where it comes into contact with the exposed portion of refrigerant conduit 27 and is cooled and recondensed. Instead of merely employing the fluid within chamber 26 as a medium through which heat is conducted, there is a vaporization-condomsation cycle of this fluid established which greatly increases the heat transfer capabilities of the fluid.

In order for this heat transfer arrangement within the mold 14 to function in the manner just described, a fluid must be chosen which will exist in equilibrium with its vapor at the temperatures experienced during the freezing cycleapproximately to 32 F. Ice making apparatus utilizing this principle has been successfully operated in which the ice mold 14 is charged with a volatile fluid having the trade name Freon 114. This fluid has a vaporization temperature of 38 F. at 15 p.s.i. absolute.

Fig illustrates the action of the mold 14 in ejecting ice pieces 16 therefrom. To effect this condition, the electric heating element 29 is energized to vaporize a portion of the fluid within chamber 3 2. As additional fluid is vaporized by heat from the heating element 29, pressure within chamber 26 is increased to the point where the cup bottom walls 25 are snapped from their concave positionto the convex position shown in Fig. 5. Because of the shape of these cup bottom walls 25 they are internally stressed to their concave position and, when sufficient pressure is built up in the chamber 26 to cause them to change position, they move with a snap action which imparts a sharp blow to the ice pieces 16, causing the ice pieces to be thrown upwardly out of the cups 22.

The heat from heating element 29 also melts the ice pieces loose from their cups -22 to facilitate their removal. It is desirable, however, that the bond between the ice pieces 16 and their cups 22 not be completely re- .4 moved prior to the snapping of the cup bottom walls 25; The battle 30 between heating element 29 and the cups 22 limits the amount of heat which is transferred to the cups 22 and is so proportioned as to permit sufficient heat to reach the cups 22 to melt a thin film of the ice pieces just as the pressure within chamber 26 reaches the point where it is desired to have the cup bottom walls 25 snap.

Heat is transferred from heating element 29 to the cups 22 principally by the circulation of heated fluid within chamber '26; the circulation being produced by convection currents in the heated fluid and by the ebulition of the fluid when vaporized by the heating element. Increasing thesize of baffle 30, i.e., decreasing the size of opening 31; reduces the circulation of fluid between chamber 32 housing the heating element, and the portion of chamber 26 surrounding the cups 22, and reduces the rate at which heat is applied to the cups 22. Conversely, reducing the size of batfle 30 would permit heat to be added to the cups 22 more rapidly, thereby reducing the time required to loosen the ice pieces in the cups.

In one sample of an ice maker utilizing this invention, the cups 22 were so constructed that a gage pressure of from 4 to 6 p.s.i. in chamber 26 was sufficient to cause the cup bottom walls 25 to snap upwardly, when unrestrained. However, to increase the ejecting force on the ice pieces 16, the baifle 30 was proportioned such that the ice pieces would not be melted loose in their cups 22 until such time as the pressure within chamber 26 had risen to approximately 25 p.s.i. gage. Thus, when the cup bottoms were released from the ice, the additional pressure available caused the bottoms to snap with considerable force to impart sufficient velocity to the ice pieces to cause them to clear the mold 14 and impinge against the deflector 15.

It will be noted from Figs. 3 and 4 that the troughs 24 connecting the ice cups 22 are more shallow than the cups 22 themselves. These troughs are preferably formed in such a manner that the bottoms thereof are only slightly below the desired level of water in the cups 22. Thus, while the troughs 24 permit water to flow between the cups 22 and enable the mold 14 to be filled by admitting water to but one cup 22, they permit but a small ice link to be formed between ice pieces 16, which is readily broken when the ice pieces are ejected from the cups 22.

Following ejection of the ice pieces 16 from the mold 14 the heater 29 is deenergized and the cups 22 refilled with water which enters the freezing unit 12 through a pipe 36 having a flexible extension 37 so as not to prevent the ejection of ice from the end cup 22. As the mold is refrigerated, the vapor within chambers 26 and 32 begins to condense, lowering the pressure within the chambers and permitting the cup bottom walls 25 to snap back to their concave position.

Deflector The ice pieces 16 ejected from the ice mold 14 must be directed into the storage container 17. Also, the film of water on the surfaces of the ice pieces which is produced by their being melted loose from the cups 22, must be removed prior to the pieces entering the storage container 17 in order to prevent the film from refreezing and causing the pieces to stick together in the container 17. In other words, before falling into the container 17', the ice pieces should be in a dry, completely frozen condition,

The deflector 15 accomplishes both of these objectives. As best shown in Fig. 1, the deflector 15 is positioned directly over the mold cups 22 in the path of travel of ice pieces 16 being ejected from these cups. The deflector is arranged to direct the ice pieces away from the mold 14 and into the open top of the container 17. As illustrated, the deflector 15 has two oppositely sloped portions 38 and 39 to deflect ice pieces into the storage container, though it is obvious that the deflector can have other configurations to direct the ice pieces into a conthe water therein.

tainer having a location other than that shown. The ice pieces 16, being ejected from mold cups 22 with considerable force, impinge against deflector 15 with a jar which shakes off most of the liquid film on the ice pieces. Whatever small amount of water remains on the ice pieces 16 following their encounter with the deflector 15 will be refrozen by the low temperature of the ice pieces and by contact with the below freezing air within freezing unit 12 prior to the ice pieces coming to rest in the storage container 17. Thus, the container 17, which is continually maintained at a temperature below freezing by virtue of its presence within the freezing unit 12, will always contain dry, individual ice pieces 16 which may be easily and conveniently removed from the container as needed.

The deflector 15 may be supported in any suitable manner, as by being attached to the freezing unit 12, as shown. Also, while the deflector 15 is shown as being made from a single solid sheet of metal, it may, if desired, be constructed of a wire mesh or other foraminous material. The foraminous material has the advantage of permitting much of the water thrown from the ice pieces impinging against the deflector 15 to pass through, thereby reducing the build-up of ice on the deflector.

Control Fig. 6 illustrates a control for the ice making apparatus of this invention, The particular control shown is an analogue type control, i.e., the control responds to conditions which are analogous to the conditions existing in the ice making mold 14 rather than directly to the mold conditions themselves. The control described herein is claimed in a copending application by the same inventor entitled Ice Making Apparatus, Serial No. 643,193, filed February 28, 1957.

The ice mold 14 of this invention is continuously subjected to a refrigerating effect by the refrigerant conduits 27 and by virtue of the presence of the mold within the freezing unit 12. The mold 14 is cycled by control 18 through intermittent energization of the heating element 29 within mold 14 and a solenoid valve 41 which admits water to refill the mold. Control 18 is positioned within the freezing unit 12 in a location in which it is subjected to a refrigerating effect similar to that to which the ice mold 14 is subjected and may rest directly on the freezing unit in close proximity to refrigerant conduits 13.

The control 18 consists of a metal block heat storage mass 42 surrounded by insulation 43 and containing a thermostatic switch 44 and an electric heater 45'. The thermostatic switch 44 is connected to one side L of the electrical supply line through a manually actuated switch 46 and controls three parallel circuits through, respectively, the heater 45, the mold heating element 29 and the solenoid valve 41, the other sides of these parallel circuits being connected to the opposite side L of the supply line. Thermostatic switch 44 is adapted to close inresponse to a reduction in temperature to energize heater 45, heating element 29 and solenoid valve 41.

1 Heater 45, when energized, adds a quantity of heat to the. heat storage mass 42 which is analogous to the combined quantity of heat added to the ice mold 14 by heating .element 29 when ejecting the ice, and by the warm water admitted to the mold 14 at the beginning of a freezing operation. The insulation 43 surrounding heat mass 42 governs the rate at which this heat is removed from the control 18 and is proportioned to permit the control to be reduced to the temperature at which thermostatic switch 44 closes in the same period of time required to remove suflicient heat from mold 14 to freeze all of Mold 14 and control 18 are refrigerated by the same refrigerating system; hence, any variations in the refrigerating eifect applied to the mold affects the control 18 in a like manner. Consequently, regardless of variations in the amount of refrigeration available to the mold 14, when the temperature of the mold has been reduced sufliciently to freeze ice in the cups 22, control 18 will also be reduced in temperature to the closing temperature of switch 44.

As indicated on the drawing, valve 41 is a three-way valve, i.e., it controls fluid flow through three conduits or pipes designated 47, 48 and 36. Pipe 47 connects with a pressurized water source which may be the ordinary household water supply system. Valve 41 is constructed in such a manner as to provide communication between supply pipe 47 and pipe 48 leading to a water measuring device 50, when its solenoid is energized. When deenergized, as shown in Fig. 6, valve 41 establishes communication between the pipe 48 connected to water measuring device 50 and pipe 36 which discharges into a mold cup 22.

Water measuring devices of the type indicated at 50 are well known and only the bare essentials of the device be here explained. As shown in the diagrammatic illustration Fig. 6, the measuring device contains a spring backed diaphragm 51 which is displaced when water is admitted to the device under pressure. The proportions of the device are such as to admit a predetermined volume of water, in this case, a volume sufficient to fill all of the cups 22 of the ice mold 14. Connecting the measuring device to an open outlet conduit, such as is accomplished by the solenoid valve 41 when deenergized, permits the spring-backed diaphragm 51 to force the measured quantity of water out of the device.

Operation Assume that the cups 22 of mold 14 are filled and that the ice pieces therein have just become frozen. Control 18 has been refrigerated along with the mold 14 and the entire control, including the heat storage mass 42, has been reduced to the temperature at which thermostatic switch 44 closes. This closing temperature of switch 44 is preset to correspond to the temperature which .the control 18 assumes when the mold 14 has been cooled sufficiently to freeze all of the water in cups 22.

The closing of thermostatic switch 44 energizes the mold heating element 29 which loosens the ice pieces 16 and causes these pieces to be ejected from the mold cups 22 by vaporizing the fluid in mold chambers 26 and 32, increasing the pressure within the chambers and causing the cup bottom walls 25 to snap upwardly. The ice pieces 16 ejected from the mold 14 impinge against deflector 15, have the water jarred therefrom, and drop into storage container 17 At the same time that mold heater 29 is energized, solenoid valve 41 is energized to admit water to the measuring device 50. Valve 50 remains energized during the period the ice pieces 16 are being ejected from the mold 14, and in this position does not admit any water to the mold. Concurrently with the energization of mold heater 29 and solenoid valve 41, the switch 44 establishes a circuit through the control heater 45 located within heat storage mass 42. Control heater 45 is of'comparatively 10w wattage and slowly raises the temperature of the components of control 18. The size of heater 45 is such that it adds a quantity of heat to the heat storage mass 42 which is analogous to the heat added to the ice mold 14 by its heater 29 and by the water which is to be admitted to the mold prior to the next freezing operation. After a period of time, suflicient to permit the ice pieces to be ejected from the mold 14, thermostatic switch 44 opens as a result of the temperature of the control 18 being raised by heater 45. This deenergizes heaters 45 and 29, stopping the flow of heat into, respectively, the control 18 and the ice mold 14. Solenoid valve 41 is also deenergized and establishes a path for the measured quantity of water in measuring device 50 to flow into the mold cups 22. The freezing operation commences as heat is removed from the mold 14 by the refrigerant flowing through conduits 13 and 27. The heat storage mass 42 within control 18 possesses a quantity of heat which is analogous to the quantity of heat within mold 14. This heat is removed from control 18 until thermostatic switch 44 closes to start the ejection of ice which will by then be frozen in mold cups 14. v

Switch 46 is normally closed, but may be manually opened to terminate operation of the ice making apparatus in the event the storage container becomes filled with ice. If desired, the switch 46 can be actuated automatically by some means responsive to the quantity of ice in the storage container 17. Automatic controls of this type, which might, for example, respond to the weight of the storage container 17, are well known. Since such a control forms no part of the present invention, no detailed description thereof is necessary here.

From the foregoing, it will be apparent that this invention provides improved apparatus for making pieces of ice automatically.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In an ice maker, an ice mold, said mold having a flexible wall portion deformable to eject ice from the mold, a first fluid-tight chamber defined at least in part by said mold, the construction and arrangement being such that said flexible wall portion of the mold is exposed to the interior of said first chamber, a second fluid-tight chamber having a lower portion thereof in communication with said first chamber, said chambers being charged with a volatile fluid, and heating means for said second chamber for vaporizing at least a portion of the fluid in said second chamber to raise the vapor pressure in both of said chambers to cause deformation of the flexib=le wall portion of said ice mold.

2. In an ice maker, an ice mold having a flexible Wall, a fluid-tight housing having an opening therein, said mold being disposed in and sealing said opening with one side of the flexible wall of said mold being exposed to the interior of said housing, a volatile fluid in said housing, means for circulating refrigerant in heat exchange relationship with the fluid in said housing to refrigerate said mold, heating means disposed within said housing in contact with said fluid for vaporizing at least a portion of said fluid whereby a fluid pressure is created in said housing to deform the said flexible wall of said ice mold and eject ice from said mold, and baffle means in said housing between said heating means and said ice mold for shielding said mold from said heating means.

3. The method of producing dry ice particles which comprises performing the following steps entirely within an atmosphere maintained at a temperature below 32 F: freezing water in a deformable mold; applying heat to the mold to melt a film of ice in contact with said mold whereby said ice is at least partially loosened from said mold; deforming said mold to forcibly eject the ice from the mold, said ice at this point having a film of water on portions of the surface thereof; causing the ejected ice to impinge against a relatively fixed abutment to jar unfrozen water from its surface; and finally, storing said ice in a container.

4. In an ice maker, an ice mold having side walls and a flexible bottom Wall deformable to eject ice from the mold, a housing enclosing the outer surface of said mold in spaced relation thereto, said housing together with said mold forming a fluid-tight enclosure, a volatile fluid within said enclosure, there being a sufficient quantity of liquid .phase fluid in said enclosure to contact the bottom wall and at least the lower portions of the side walls of said mold,'and heating means in said housing in contact with said liquid phase fluid, said heating means when energized warming said liquid phase fluid to at least partially loosen ice in said mold and vaporizing at least a portion of said liquid phase fluid to raise the vapor pressure in said enclosure to cause deformation of the bottom wall of the mold and eject. ice from said mold. I 5. In an ice maker, an ice mold, said mold having a flexible wall portion deformable to eject ice from the mold, a'first fluid-tight chamber defined at least in part by said flexible wall portion of said mold, a second fluidtight chamber having a lower portion thereof in communication with said first chamber, a volatile fluid in both of said chambers, a refrigerant conduit in said first chamber and cooling said ice mold, and heating means in said second chamber for warming said fluid to at least partially loosen ice in said mold and for vaporizing at least a portion of the fluid in said second chamber to raise the evaporator pressure in both of said chambers to cause deformation of the flexible wall portion of said mold. I 6. In an ice maker, an ice mold having side walls and a flexible bottom wall deformable to eject ice from the mold, a housing enclosing the outer surface of said mold in spaced relation thereto, said housing together with said mold forming a fluid-tight enclosure, a volatile fluid within said enclosure, there being a sufficient quantity of liquid phase fluid in said enclosure to contact the bottom wall and at least the lower portions of the side walls of said mold, heating means in said housing in contact with said liquid phase fluid, said heating means when energized warming said liquid phase fluid to at least par tially loosen ice in said mold and vaporizing at least a portion of said fluid to increase the fluid pressure in said housing to deform the flexible wall of said mold and eject ice from the mold, and means in said enclosure for inhibiting the flow of liquid phase fluid between the region of said mold and the region of said heating means for limiting the rate at which heat is applied to said mold.

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