US2606428A

US2606428A - Refrigerated cube grid

Info

Publication number: US2606428A
Application number: US152171A
Authority: US
Inventors: Charles L Oldfather
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-03-27
Filing date: 1950-03-27
Publication date: 1952-08-12
Anticipated expiration: 1969-08-12

Description

8,- 12, 1952 c. 1.. OLDFATHER 2,606,428

REFRIGERATED CUBE GRID Filed March 27, 1950 3 Sheets-Sheet 1 ATTORNEYS c. L. OLDFATHER REFRIGERATED CUBE GRID Aug.

3 Sheets-Sheet 2 Filed March 27 1950 ATTORN E YS 12, 1952 c. OLDFATHER I REFRIGERATED CUBE GRID 5 Sheets-Sheet 3 Filed March 27 1950 INVENTOR ATTORNEYS Patented Aug. 12, 1952 UNITED STATES PATENT OFFICE REFRIGERATED CUBE GRID Charles L. Oldfather, Seattle, Wash.

Application March 27, 1950, Serial No. 152,171

This invention pertains to a grid for the formation of ice cubes which has numerous advantages over trays presently in use. The improved grid structure is particularly designed for the commercial manufacture of ice cubes in which it is of primary importance that the product be completely clear and contain no entrained air or other gases.

It has'been common practice in the art to circulate water over a tray containing a cube grid to form the clear cubes. This method of freezing ice cubes has raised many problems, one of which is that the tray is refrigerated on the bottom only, thus only the bottom of each cube is exposed to the effect of the refrigerant, resulting in slower freezing and in other incidental inefficiencies. The present invention contemplates refrigerating each cube compartment along at least two of its sides to evolve a maximum heat transfer and an even freezing cycle of all the cubes'in the grid. The invention further contemplates making use of direct expansion ofthe refrigerant along either two sides or four sides of each cube cell, thus providing a maximum area for eflicient heat transfer and greater assurance of an even freezing cycle, resulting in more inexpensive operation.

In the present invention the refrigerant may be directed about either two sides of each cube cell or about all four sides thereof. The refrigerant may be conducted around the cube cells in the grid by means of appropriate tubing or by passes or channels cast in the grid by any convenient method, the primary consideration being that each cube cell shall be refrigerated equally with all other cube cells to insure an even freezing cycle.

In the present invention the cube grid cells are completely open at both their top and bottom surfaces to facilitate agitation of the water contained in the grid cells to remove trapped air and gases during the freezing process. By virtue of this construction the agitation may be accomplished either by water turbulence or by air stream.

As the refrigerant is circulated only in the walls of the cube cells the ice formation is from the side walls of the cells toward their centers and thus a passage for air or circulation water is maintained centrally of the cube until the entire cube is frozen. It has been usual in the commercial manufacture of clear ice cubes with conventional grids to submerge the tray in an excess of Water to provide the necessary turbulence to 2 remove entrained gases therefrom. Refrigeration of this excess water has therefore taken place, resulting in considerable wasted energy. With the present cube grid this disadvantage has been eliminated.

It is therefore one object of this invention to provide an improved ice cube grid which will insure an even freezing cycle of all the cubes.

Another object of this invention is to provide such a grid of such structure as to produce completely clear ice with no content of entrained gases. g

A further object of this invention is to provide such a grid which is more eificient and whose freezing cycle is shorter than that of trays currently in use.

Other and further objects of this invention will become apparent as this specification proceeds.

Referring to the drawings:

Fig. 1 is a top view of one embodiment of the cube grid, broken through the center;

Fig. 2 is a side view of this embodiment of the invention looking from the outlet side of the grid;

Fig. 3 is a cross sectional view of this embodiment of the invention taken on line 3-3 of Fig. 1;

Fig. 4 is a partial section view of the embodiment of the grid shown in Fig. 1, taken on line 4-4 of Fig. 1; n

Fig. 5 is a perspective view of an ice cube as produced by the embodiment of the invention shown in Fig. 1;

Fig. 6 is a vertical plan view of an alternative embodiment of the invention with the top tube sheet removed, broken in'the center; Fig. '7 is a cross sectional view of this embodiment of the invention taken on line 7-1 of Fig. 6 and broken in the center;

Fig. 3 is a cross sectional view of the embodiment of the invention shown in Fig. 6, taken on line 8-8 of Fig. 6 and broken in the center;

Fig. 9 is a vertical plan view of the embodiment of the invention shown in Fig. 6, with the top tube sheet removed, showing the path of flow of the refrigerant through the conduits between the cube compartments and the effect of the baffles therein;

Fig. 10 is a partial section view taken on line ill-l0 of Fig. 9; and

Fig. 11 is a partial section view taken on line H-ll of Fig. 9.

In the embodiment of the invention shown in Figs. 1, 2, 3 and 4, [5 indicates broadly the metal cube grid which may be pressure die cast of aluminum or an analogous metal and which as shown is preferably rectangular in shape and of greater length than width. Grid I5 is composed broadly of longitudinal side walls l6, end walls [1, intermediate longitudinal walls I8 and intermediate lateral walls l9, which define a series of rectangular, downwardly tapered ice cube chambers 20. Cube grid l5 preferably contains five'of. the tapered ice chambers. 2|] across its width and fourteenalong its length, making a total of sixty ice chambers in all, however the number of chambers or compartments may be varied at will without departing from the spirit of this invention.

Disposed centrally of longitudinal outer. walls l6 and longitudinal inner walls I8; which are appropriately bored or cast to; receive ,it',y is a refrigerant tubing 2| which is preferably formed. of cadmium plated full. annealed steel tubing but which may be of any 'other appropriate material. As shown in-Fig. l" refrigerant tubing- 2| initiates at inlet' 22, runs longitudinally the length of longitudinal wall 5, through the center thereof, is then turned and passesback through the center of longitudinal wall l8 and then is turned and passesback and forth through the centers of the balanceof-the-longitudinal walls 8 of the'gridto pass through the center of the oppositelongitudinal wall |6 of-the-gridtooutlet'vent 23: The preferred location of the refrigerant tubing 2| in the longitudinal walls l5 and laof the grid is shown in Fig. 4 of the drawing. Itwill be-noted that tubing 2| is so located in the longitudinal walls of grid |5as to contact the median line of icepocketsZO. Thus, refrigerant entering tubing 21 at inlet duct 22 makes-a complete circuit through tubing 2 I through the centers of all of thelongitudinal walls of grid l5 before leaving the grid at outlet vent 23 It will be observed'from Figs. 2, 3- and; of the drawings that the longitudinal walls Hi and I8 and'lateral walls |1' and I9 of'the grid I 5' progressively increase in thickness from their top to their bottomextremities to provide a downward taper to rectangular ice pockets 20.

If desired, in place of tubing 2| a circular refrlgerantp'ass maybecastinto the longitudinal walls of grid I5 during the die casting operation.

Grid I5 is preferably 'insulated at its two longitudinal extremities by insulation layer 25 of rubber or other-suitable material and is insulated along itslateral edges'byinsulation sheets 23 of similar material. These insulating sheets 25 and j26 are preferably-bonded to the longitudinal and lateral outer walls of'gri'd IS. The" inner longitudinal'and lateral walls of grid |5 are preferably insulated top and bottom by strips of rubber or similar insulation 21- and28 which are appropriately bonded thereto; The provisionuof these outer insulating coatings over grid l5 eliminates cold' loss and greatly increases the efficiency 'of the grid. It will be noted that refrigeranttubing 2| and inlet and outlet vents 22 and-23 for the refrigerant tubing are appropriately bonded within insulation coatings 25. These coatings and upper and'lower coatings-21 and 28*are bonded over grid l5-after refrigerant tube 2| has been inserted longitudinally therethrough. Where open refrigerant passes are cast through the longitudinal walls of grid l5, complementary tubesor passages must be provided in the two terminal insulatingcoatings 25.

It'will therefore be seen that in the embodiment of the invention shown in Figs- 1, 2, 3 and 4- the complete grid-structure comprises a rectangular metal grid l5 consisting of rectangularly disposed longitudinal and lateral walls It, l8 and |1, |9 respectively, which define rectangular ice cube pockets 2!] which are open at both their top and bottom extremities and which have a slight downward taper. All external surfaces of the metal grid are appropriately insulated by layers of insulation which are bonded thereto. Therefore, the only metal surfaces of the grid which are not'covered by an insulating layer are the four inner walls of each of the ice cube pockets 23, between which the ice cubes are formed.

An alternative embodiment of the invention is shown in Figs. 6-11, inclusive. In this embodiment of the invention the grid instead of being pressurefdie cast is fabricated from a number of short lengths of square tubing 30, preferably of copper or analogous metal, which are appropriately assembled to formthe grid. The preferred method of forming this embodiment of the. grid is as follows: Top tube sheet, 3| and bottom..tube

sheet 32 are preferably stamped out of rectangular sheetsv of copper or'analogous mate-- rial and carry parallel series of, square openings stamped therein to the size of, square tubing inserts 30. Tubing inserts 30 are then fitted intov the square openings in bottom tube sheet- 32-.

tubinginserts 30, which are fitted into the square openings therein, in such fashion that the upper edges of tubing inserts 39' are fiush with the upper surface of top tube/sheet 3|, which lies in a plane parallel to the planeofbottom'tube sheet 32. End. walls 33' and... longitudinal .walls 34 are then inserted betw-een.zthe outeraedgesof top andbottom tube sheets 3| and 32 and the'entire grid 'assembly'is sealed by oven brazing. End walls 33' and. longitudinal walls 34 are preferably formed of'rectangularpiecesof copper'or analogous metal.

The grid thus formedcomprises a' series'of ice cells or pockets 35 which are separated by, and whose walls are in contact with, rectangular longitudinal refrigerant channels 36 and lateral refrigerant channels 31. Thus, all four walls of each ice cell 35 are contacted by refrigerant circulating through channe1s'36 and 31.

It will be noted that upper tube sheet 3| and lower tube sheet 32 are of such'widthas to provide outer longitudinal

refrigerant channels

38 and 39 of substantially twice the Width of

channels

33 and 31, and extending the entire length of the grid assembly.

It will be further noted that each of cube cells 35 is open at both its top and bottom surfaces.

Inlet tube 40 is shown provided at one corner of the grid structure and preferably comprises a cylindrical tube which is suitably afiixed in end wall 33 of the grid and communicates with the interior of the grid. Outlet tube 4| is shown suitably afiixed in the opposite end wall 33 of the grid structure and communicating with the interior of the grid at the opposite extremity of outer longitudinal grid channel 38.

A series of

staggered baflles

42, 43, 44, 45, 46, 41 and 48 are provided extending laterally across the grid structure through alternate lateral channels 31. Ballies 4248, as shown, are alternately afiixed to opposite side walls 34 of the grid structure and extend from top to bottom of the grid channels 31, but terminate short of analogous metal.

their lateral extremities, in such fashion that longitudinal channels 38 and 3,9 of the grid structure are alternately open at the extremities of said baffles. Baffies 42-48 are preferably rectangular in shape and are formed of copper or They are designed to prevent short circuiting of the refrigerant in the refrigerant channels, or the bypassing of any of the ice cube pockets 35. Fig. 9 of the drawing illustrates the paths taken by the refrigerant on its course through the channels of the grid structure, from inlet duct 40 through to outlet duct 4!. It will be seen that by virtue of these baffles the refrigerant follows a serpentine course through the hollow walls of the grid structure from inlet duct 40 to outlet duct 4|, whereby a uniform refrigerating action on each of the ice pockets 35 is produced.

A suitable outer insulating sheet or covering of rubber or other appropriate material is provided over all outer metal surfaces of this embodiment of the grid structure. A layer of durable insulation is prvoided over the

outer walls

33 and 34 of the grid structure and is appropriately bonded thereto. A layer of suitable insulation is also bonded or otherwise appropriately aflixed over the top and bottom metal surfaces of the grid. Lateral insulation layer 50, top layer 5| and bottom layer 52 provide a complete insulation for all external metal walls of the grid structure and prevent undue cold losses. Inlet tube 40 and outlet tube 4! are appropriately imbedded in lateral insulation strip 50 and the cylindrical tubings leading therefrom are also appropriately insulated.

As in the first embodiment of the invention, ice cells 35 are open at both their top and bottom extremities to facilitate flow of water therethrough and to permit suitable agitation of the contained water to remove occluded air and gases to produce a clear ice cube. The structure of ice cells 35 is clearly shown in Figs. 7, l0 and 11, each comprising a rectangle open at both its top and bottom surfaces.

In this embodiment of the invention it will be noted that the cube grid preferably contains five rectangular ice cells or pockets across its width and fourteen along its length. However, the number of cells may be varied at will without departing from the spirit of the invention.

This embodiment of the invention lends itself readily to economical mass production and obviates many of the manufacturing problems which were previously inherent in the manufacture of grids. The insulating layer applied over all metal surfaces of the grid greatly increases its efficiency, and the internal staggered baffles previously described assure a complete and equalized circulation of the refrigerant fluid about each of the grid cells.

Regardless of which of the embodiments of the invention is used it is preferred that flexible refrigerant lines be affixed to the inlet and outlet ducts of the cube grid so that the grid is a completely closed and easily portable refrigeration circuit. The grid therefore may be moved mechanically into or away from the water tank in which the cubes are frozen. This serves a dual purpose: the water need not be handled or controlled other than by a simple float valve, and the problem of transporting the ice cubes to storage is resolved by allowing the grid to defrost in such manner that the cubes will be guided into the storage space.

The refrigerant which is recommended for use with the novel cube grids is Freon 12, but any other analogous refrigerant may be utilized with equally good results. The average freezing cycle for ice cubes made in conformity with this in-' vention is approximately twenty minutes, which cycle may vary slightly. v

Each of the cube grids lends itself readily to economical mass production and by the provision of the refrigerant channels along two or more sides of each individual cube compartment a maximum heat transfer is developed and an even freezing cycle of all cubes is assured. By utilizing these cube grids the refrigerant is literally made an integral part of the freezing grid and in effect constitutes a direct expansion systern.

The grids may be defrosted after each freezing cycle by a forced air current, or, if desired, high resistance electric wire may be imbedded in the insulation. A hot gas defrost system may be provided by utilizing the hot gas contained in the compressor unit.

The novel grids are intended to be used with any mechanical refrigeration compressor or with any appropriate absorption unit. Heat is thus taken directly through the cell walls by the circulated refrigerant which eliminates the necessity of using an antifreeze medium and provides a maximum efiiciency with a minimum of cold loss.

As the refrigerant passes only about the sides of the cube cells the ice formation is from the walls of the cube cells to the center of the cell and thus a passage for the circulation of air or water is maintained until the entire cube is frozen. This could not be accomplished in a tray unless the bottom were formed of a separate nonconducting material.

The invention is susceptible of numerous embodiments without departing from the spirit thereof, Attention is directed to the appended claims for the limitation of its scope.

What is claimed is:

1. In an ice cube grid, a metal grid body composed of rectangularly disposed and intercommunicating hollow walls, said walls defining a series of open ice pockets in said grid body, a series of staggered baffles alternately affixed to opposite side walls of said grid body and extending laterally through said grid body, a refrigerant inlet communicating with the interior of said grid body, a refrigerant outlet communicating with the interior of said grid body, and an insulating layer covering all external surfaces of said grid body.

2. In an ice cube grid, 2. metal grid body composed of rectangularly disposed and intercommunicating rectangular hollow walls, said walls defining a series of ice pockets open top and bottom in said grid body, a series of staggered baffles alternately aflixed to opposite side walls of said grid body and extending laterally substantially the entire width of said grid body, a refrigerant inlet at one extremity of said grid body communicating with the interior thereof, a refrigerant outlet at the opposite extremity of said grid body communicating with the interior thereof, and an insulating coating covering all external surfaces of said grid body.

3. In an ice cube grid, a metal grid body composed of rectangularly disposed and intercommunicating rectangular hollow Walls, said walls defining a series of ice pockets open top and bottom in said grid body, lateral refrigerant channels substantially twice as wide as the space between said; walls extending longitudinally of the; grid structure, at its. lateral edges and communicating with the interior space therein. be-. tween said; walls, a series- 01- staggered bafiles alternatelyaflixed toopposite side walls of, said grid body and extending laterally substantially the. entire width of said grid-body, a, refrigerant 1111 86360116 extremity of saidv grid body communicating, with thev interior thereof, arefrigerant outlet at the-oppositeextremityof sai v id body, communicating; with the interior thereof, and a rubber insulating coating; covering all, external surfaces of said grid. body:

4 In amicelcube r dl me a id b r fi e ing-rectangular lateralandi longitudinal refrigerant channels rectangularly disposed about the sides ,ofa seriess of i ice pockets open top; and botom i sai r ody n it d e a nelsof-substantiallytwice the-width of; said interiot. channels. extending longitudinally of said grid,at .each side thereof, and communicating with said interior channels-,a series of staggered bamesalternately-aflixed to. opposite side-walls of said grid; body and extending laterally substantially the entire width of said grid body, a refrigerant inletat one extremity of said grid body communicatingwith the extremity of one 01 said longitudinal side channels, a refrigerant-outlet at thev other extremity of said grid body communieating with the extremity of the other of said longitudinal side channels and av rubber insulating. coating; covering. all external surfaces of said grid body.

CHARLES L. OLDFATHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date.

1,757,033 Wolcott May 6,1930 2,117,658 Gilliam May 17,1938 2,221,212 Wussow Nov. 12, 1940 2,226,271 Vose .Dec, 24,1940 2,339,109 Pownall Jan. 11,1944 2,523,956 Kleist Sept. 26,1950 2,526,262 Munsho-wer Oct. 17, 1950