US2621486A - Method and apparatus for maintaining uniform temperature in frozen masses - Google Patents

Description

Dec. 16, 1952 w. L. MORRISON 2,621,486

METHOD AND APPARATUS FOR MAINTAINING UNIFORM TEMPERATURE IN FROZEN MASSES Filed Oct. 20, 1945 2 SPEETS-SI'IEET 1 Inventor flttorneya Dec. 16, 1952 w g sou 2,621,486

METHOD AND APPARA US FDR MAINTAINING UNIFORM TEMPERATURE IN FROZEN MASSES Filed 001'" 20, 1945 Z'SHEETSSHEET 2 .A/orrz'aan fl tiara/6 14 Valiant 57 P Patented Dec. 16, 1952 METHOD AND APPARATUS FOR MAINTAIN- ING UNIFORM TEMPERATURE IN FROZEN MASSES Willard L. Morrison, Lake Forest, Ill.

Application October 20, 1945, Serial No. 623,507

3 Claims. 1

My invention relates to an improved refrigeration assembly for shipping purposes and to an improved method of refrigerated shipping.

One purpose is to provide an improved means for and method of shipping pre-cooled materials which are initially reduced to a very low temperature and are thereafter shipped or stored for substantial periods without further cooling.

Another purpose is to provide an improved means of and method for employing the initial super-chilling of materials as the cooling medium for maintaining them at a satisfactory low temperature during a period of shipping or storage or both.

Another purpose is to provide an improved means of and method of shipping refrigerated materials.

Another purpose is to provide an improved shipping assembly for refrigerated materials.

Another purpose is to provide improved containers in which materials may be shipped while being kept at low temperatures.

Another purpose is to provide an improved shipping method and assembly adaptable for shipping refrigerated materials in railroad cars, trucks, airplanes, sh ps and the like.

Other purposes will appear from time to time in the course of the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawings wherein:

Figure 1 is a transverse vertical section;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is a transverse vertical section illustrating a variant procedure; and

Figure 4 is a longitudinal vertical section illustrating a variant procedure.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, and first to the form of structure illustrated in Figures 1 and 2, I illustrate an outer insulated container which in the drawings is shown as a relatively thick walled freight car body. I illustrate for example a structure including outer walls I, inner walls 2 and any suitable intermediate insulation. I may for example employ blocks or cartons 3 filled with a suitable insulating material. Any suitable access means may be provided and I illustrate for example a bodily removable car top 4 which may be similarly formed and insulated. The car bottom 5 is also insulated. Preferably in a freight car of standard 40 ton size I may provide about 7" of insulation of the material having the effect or insulating quality of Santocel. It will be understood, however, that any suitably insulated container may be employed. Whereas I illustrate my method as carried out by the employment of a car body mounted for example on flanged wheels 6 riding on rails i, it will be understood that I may employ a body or insulated container separable from the running gear, or applicable to other supports. I may for example employ an insulated container which may be bodily positioned in an airplane or in a ship.

Within the outer insulated body or housing I illustrate a plurality of separate containers which may be filled with the material to be shipped. Each said container may for example be formed of walls of material having heat conductivity. In Figs. 1 and 2, I illustrate, for example, containers having plane top and bottom walls It, H, plane end Walls I 2 and corrugated interfitting side walls l3,the walls all being formed of aluminum or some other material having advantageous heat conducting characteristics. One of the walls, such as the top wall t, may be made removable to permit insertion and removal of material. Whereas the corrugated side Walls are advantageous as increasing the heat transfer area between adjacent containers, and also for increasing the stiffness of the structure when supported by the ends, it will be understood that plane walls may be substituted if desired. What is essential is that the walls of adjacent packages or containers shall be in intimate contact over a maximum area, in order to maintain so far as possible, uniform temperature conditions within the entire mass of material housed in the car body or outer housing. Preferably the containers are so proportioned that every container in the car loading is in contact with the insulation adjacent to, or in one of the side walls of the car. Thus, in Fig, 1 I illustrate the containers which may be indicated as A, as extending from the inner side wall member 2 to the center of the car as at B. Thus substantially uniform heat transfer conditions exist, throughout the mass, between the individual containers and the insulation of the outer container or housing-or car body in which they are housed. It is also important that the parts are so proportioned that the containers fit snugly together and contact both each other and the insulation of the car side bottom and end walls. In this connection it is advantageous, although not strictly necessary, to have the roof of the car bodily removable, so that the individual containers may be lowered into the interior of the car body and stacked in proper position.

A somewhat less efficient method of maintain ing the desired uniformity of temperature conditions throughout the mass is to employ intervening layers of material having high heat conductivity characteristics. Thus in Fig. 3 I may arrange the individual containers B, of somewhat less length than the containers A of Figs. 1 and 2, in three tiers, with intervening layers 25 of a heat conducting metal, such as aluminum, extending from end to end of the car and in contact with the upper and lower walls of the car. In the form of Fig. l I illustrate similar transverse elements 2! which extend from side to side of the car and contact also the top and bottom. The individual packages or containers C of Fig. 4 may be made of plane sheets of aluminum or of other material. For example, where packages 01' masses packed inpaper are handled, paper packages may be so arranged as also to contact transversely extending heat conductivity elements 21. Whereas I have illustrated such elements as spaced apart in Fig. 4, by the width of two stages of packages or containers, they may be arranged between each row or even may be more widely spaced, depending upon the needs of the particular substance handled.

It will be realized that whereas I have described and illustrated a practical and operative device,

nevertheless many changes may be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I

therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to my precise showing, and as showing examples of mechanisms which can be used to carry out my procedure.

The use and operation of the invention are as follows:

The procedure followed in connection with the employment of the shipping assembly herein shown is as follows. The outer container or car body itself is initially reduced to alow temperature. It may for example be reduced to a temperature of the order of 20 degrees below zero or lower, or the inner space or the inner walls of the car may be thoroughly chilled, to a similar temperature, without at the same time reducing the exterior temperature of the car to any such degree. The individual containers or packages are filled or formed, and are not themselves insulated. The inner containers are preferably of high heat conducting material, such as sheet metal aluminum plate or the like. The material is superchilled, in said containers, to temperatures substantially lower than that of Dry Ice. Or the materials may be so processed before being inserted into the individual containers, that the containers themselves will shortly be chilled to the desired low temperature by the cold material with which they are charged. The containers are then stacked or arranged in the car, preferably being disposed, as shown in Fig. 2, with some part of each container in contact with an inner face of an exterior wall of the outer housing. This, in connection with the high heat conductivity of the container walls, causes the entire mas to warm up more evenly as heat is conducted inwardly through the outer housing than would be otherwise the case. Thus the warming up of the entire body of food within the car or outer housing permits the outer portions of the food or other material to arrive at destination at substantially the same temperature as the food or material of the inner part of the load. An important characteristic of my method is the handling of a large bulk of material, surrounded by an adequate outside housing of good heat insulating characteristics, under conditions which maintain a substantially even temperature throughout the entire mass of material shipped or stored. In Figs. 1 and 2 I obtain this result by maintaining the individual sub-containers in good heat transfer relationship with each other, and with the outer housing. Somewhat less efficient are arrangements such as shown in Figs. 3 and 4, in which sheet members 20 or 2! of high heat conductivity pass through the body of frozen food or material, in such spacing as to cause the entire mass to warm up generally evenly. Where separate heat conducting plate members are employed, of aluminum or other suitable material, the material in the individual packages may be separated from the plate members by outer walls or layers having a minimum resistance to the passage of heat. Oil paper, or thin board, or sheet metal, or any other suitable material may be employed for the individual sub-containers or packages.

In applying my method to a freight car of standard size I may employ a hollow walled body with a suitable insulating material between the walls. I may for example apply a layer of 7" 0i Santocel insulation. The insulation is tamped between the walls, or applied by packing in car.- tons, as shown in one wall of Figure 1. The employment of separate cartons prevents any escape of the insulating material from the interior of the cartons. It may also be advantageous to employ flocks on the exterior surface of the cartons.

Whereas as shown in Fig. 3 I may, if necessary, employ an intermediate row of packages B which do not engage the side walls, these packages will be maintained in contact either with longitudinally extending heat transfer plates 2B, or with transversely extending heat transfer plates 2|, the latter being shown in Fig. 4.

A general characteristic of my method is to superfreeze the mass of material in such fashion that when the car or other outside container starts on its trip the entire mass of material r within the outer container or car body is initially at an exceedingly low temperature, a temperature which may be lower than that of Dry Ice. This mass of initially supercooled material constitutes the sole refrigerating medium employed during shipment. During shipment, and during subsequent storage, until the load is opened, the transverse heat conducting members 20 and 21, or the heat conducting walls of the containers A serve to maintain a substantially uniform temperature condition throughout the mass. This uniform temperature condition is favored also by the arrangement of containers A as shown in Figs. 1 and 2, in which each container itself engages a wall of the surrounding outer housing.

Whereas my method may be applied advantageously to freight cars it will be understood that it may also be applied to motor trucks, and to shipping containers which are readily movable and may be shipped by airplane or by boat. Where a large number of such containers are employed, as in boat cargoes, the outside containers, with preferably of plane exteriors, may abut against each other in order to limit or reduce the outer surfaces of the entire mass which are exposed to ambient temperature. By employing rectangular containers with flat tops, the outer containers themselves may be stacked one upon the other.

Where my method is applied to ordinary railroadtransportation, it is advantageous to employ 5 a freight car body as the container. As indicated in Figs. 1 and 2 I illustrate the roof of the freight car body as removable. stood that any other means for obtaining access to the interior of the freight car body may be employed.

I claim:

1. In combination, a receptacle having a heat insulating outer housing, a plurality of separate fluid tight metal boxes so shaped that they may be assembled into a compact mass within the housing substantially completely filling it, each box containing a mass of frozen material substantially completely filling the box at a temperature substantially below zero, each box being in contact throughout its entire surface with the boxes around it except where a box may be in contact with a wall of the housing, separate heat conducting means within the housing in contact with the walls thereof and extending throughout the mass in contact with at least one wall of the boxes adjacent to it.

2. In combination, an insulated receptacle having heat conductive plates extending across the area thereof between the walls and in contact with the walls, a plurality of metallic boxes, each substantially filled by material, the temperature of which is substantially below zero, said boxes being contained within the housing and in contact with at least one Wall of the housing or the conducting member and each surface of each box being in direct heat conductive contact with the surface of the box adjacent to it to insure a di- It will be underrect flow of heat throughout the entire mass both vertically and horizontally in directions perpei dicular to the walls of the container.

3. The method of preserving food and the like which consists in assembling a mass of food, subdivided into a plurality of separate abutting bodies, all at a temperature substantially below zero F., enclosing the assembled bodies of food in the absence of any other refrigerant in an insulated zone, conducting heat through the mass along the boundaries between the abutting food bodies at a substantially uniform rate, higher than the normal rate of heat fiow within each body, to maintain uniform temperature conditions throughout the entire mass as the temperature of the mass rises.

WILLARD L. MORRISON.

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

UNITED STATES PATENTS Number Name Date 973,082 Smith Oct. 18, 1910 1,765,591 Kellett June 24, 1930 1,825,643 Martin Sept. 29, 1931 1,929,511 Mulkey Oct. 10, 1933 2,007,154 Bowes July 9, 1935 2,203,033 Spiegl June 4, 1940 2,260,450 Guinane Oct. 28, 1941 2,393,245 Hadsell Jan. 22, 1946

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