US2436389A - Refrigerating plate and internal reinforcement therefor - Google Patents

Description

H. W. KLEIST Feb. 24, 1948.

REFRIGERATING PLATE AND INTERNAL REINFORCEMENT THEREFOR 2 Sheets-Sheet 1 Filed Sept. 4, 1945 I 727/67271'07" zermajz Wl lez si' E9 PM w H. W. KLEIST Feb. 24, 1948.

REFRIGERATING PLATE AND INTERNAL REINFORCEMENT THEREFOR Filed Sept. 4, 1945 2 Sheets-Sheet 2 .Afivenzov- .Herman Wjf'lezjs @454 mm emnteareb. 24, 1948 REFRIGERATING PLATE AND INTERNAL REINFORCEMENT THEREFOR Herman W. Kleist, Chicago, Ill., asslgnor to Dole Refrigerating Company,

ration of Illinois Chicago, 11]., a corpo- Application September 4, 1945, Serial No. 614,420 3 Claims. (Cl. 62-126) My invention relates to an improvement in refrigeration and relates particularly to the structure of cold plates.

One purpose is to provide an improved cold plate for refrigerators and the like- 'Another purpose is to provide an improved plate in which a variable volume of liquid is em- I illustrate the invention more or less diagrammatically in the accompanying drawings, wherein:

Figure 1 is a side elevation with parts in skeleton outline and parts broken away;

Figure 2 is a section on an enlarged scale on the line 22 of Figure 1;

Figure 3 is a detail section on a still larger scale;

Figure 4 is a section on the line 44 of Figure 3; and

Figure -5 is a detail section on the line 5-5 of Figure 2. Figure 6 is a vertical section on an enlarged scale of an embodiment in which but a small amount of eutectic fluid is used.

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

Referring to the drawings A indicates generally a cold plate including a coil in circuit with a mechanical refrigeration mechanism. The mechanical refrigeration mechanism is diagrammatically shown at B. It includes a base i, any suitable compressor 2, driven by a motor 3 through the belt 4. I diagrammatically indi-- cates any suitable condenser coil and 6 is any suitable receiver. 1 is a high pressure duct extending from the receiver to any suitable expansion valve diagrammatically indicated as at 8. .9 is a refrigerant delivery duct extending from ,the expansion valve "liquid refrigerant, for

described evaporator structure.

8 and adapted'to deliver evaporation, to the below I0 is a low pressure return duct adapted to return the evaporated refrigerant to the compressor. more specifically to the cold plate which is included in the above mentioned cycle I employ a coil which includes a plurality of rectangular and preferable rectilinear pipe lengths l5. These Referring;

pipe lengths may conveniently be assembled in groups of like length. Two such groups are shown in Figure 1 forming an upper coil C and a lower coil D. The employment of rectilinear pipes provides a coil having flat faces defined by parallel planes. This arrangement is ideal for use in cold plates.

Referring, for examplerto Figure 2, I employ a plate having parallels walls It and H which are sealed together at their edges, for example, by the employment of flanges l8 on one such wall welded or otherwise secured as at l9 to the opposite wall. The coil formed of the rectangular tube lengths l5 therefore abuts against the inner faces of the walls It and I! with a maximum area of close contact. In forming coils of rectangular cross section, it is not advantageous to bend the coil. I may find it advantageous to employ preformed couplings or connectors which may be bent or otherwise formed from tubing which'is not rectangular in cross vsection. Referring for example to Figures 3 and 4, I illustrate connectors 20 which may be bent or otherwise formed from tubing having a generally circular cross section, each such connector may terminate at each end in a single common plane as at H, .22. Such a connector may then be easily welded as at 23 to the adjacent end of an adjacent pair of rectangular rectilinear tubes l5. If any excess metal is provided it maybe ground'ofl or otherwise smoothed off to provide a flush surface such as is shown in Figure 4. Preferably the diameter of the connector 20 is the same as the diameter of the tubes l5, to provide a maximum contact with the inner faces of the walls l6 and I1.

In the particular plate shown in Figure 1, I illustrate a connector having a nipple 25 to receive the end of the refrigerant inlet 9 or of any elbow or connector member applied thereto. One branch of the connector 24 extends to the coil C and the other to an intermediate passage or duct'26 which extends to the upper tube I511. of the coil D. A discharge fitting or connector 21 is employed, one arm of which receives the outlet duct 28 of the coil C. The nipple 30 is in communication with any suitable fitting and is adapted to connect it with the evaporant return duct I 0. It will be understood that any suitable eutectic may be located within the space within the walls l6 and 11. Preferably I also subject the space within the plate to a vacuum. 3| indicates any suitable fitting or valve enclosure where the eutectic fluid may be admitted to the space between the walls I 6 and I! through After the eutectic fluid has been introduced I may employ the fitting 3| as a means for exhausting the air from the interior of the plate to provide a partial vacuum. The ball 3 serves as a check valve against the entry of atmospheric air. 35 is any suitable drainage fitting for draining the eutectic liquid from the interior of the plate.

In Fig. 2 I illustrate a form of plate the interior of which is largely filled by a eutectic fluid, the top level of the fluid being indicated at X. It will be understood that the volume of the fluid may be varied but that I prefer substantially to .1111 the interior of the plate, while leaving adequate space to take up the expansion of the fluid when it freezes. The fluid not merely serves as a hold-over. but provides the necessary moisture for maintaining a. heat transmitting film between the opposed outer side faces of the coil lengths i and the inner faces of the side walls l6 and I1. If the fluid is admitted through the connector 3|,

-it is free to fill the interior of the plate. In order to permit the liquid to flow to the entire space within the plate. I may slightly reduce the di ameter of the curved bent portions 20, at least locally. Or it may be convenient to provide an additional. inlet. not herein shown, to assist in the rapid filling of the plate.

In the form of Fig. 6. I use a much smaller volume of fluid. illustrated at Y. The hold-over factor. in the form of Fig. 6, is omitted, but enough l quid is delivered to the interior of the plate to provide the necessary moisture for maintaining the heat transmitting films between the op osed faces of the coil lengths l5 and the side walls i6 and I1. I

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 inventlon.- 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.

For example, I may employ a single coil within the cold plate instead of using the two coils which I show connected in. parallel, as shown in Figure l. I may also employ any suitable means for spacing or supporting the coils in a plate. I illustrate for example, the supports or spacers In in Figure l which may be employed in any suitable size, shape, number, and location.

A convenient and valuable embodiment of my invention is a coil having a plurality of rectilinear tubes of rectangular cross section, the tubes being connected to form a continuous coil, but pre formed or separately formed connectors which may advantageously be non-rectangular, or circular in internal cross section.

It will be understood, for example, that I may. within the scope of my invention and within the terms of my claims, employ a unitary tube structure in which a rectangular tube is actually bent, and I do not wish to limit myself either to the employment of separate connecting portions or to the specific form or contouring or curvature of the connecting portions, since my invention includes any fluid conductive connection between adjacent rectilinear duct lengths.

The use and operation of the present invention are as follows:

The efilciency of the plate herein shown and claimed depends upon the: adequacy of the heat transfer between the coil, within which the refrigerant is evaporated, and the opposed side walls it and i! of the plate. Sufficient fluid is admitted to the interior of the plate to permit the building up of films. The area occupied by the films is extended by the employment of square tubing, involving a substantial increase of direct heat transfer area, as contrasted to structures in which round or oval tubing is employed. The liquid. such as a eutectic. provides the necessary material for the films, whether only a small volume is admitted, as in Fig. 6, or whether a large volume is admitted. as in Fig. 2. In the form of Fig. 6. it may be desirable to agitate the plate. to obtain an initial distribution of the liquid. before exhausting the interior of the plate.

In both forms of plate the interior is sufficiently exhausted to maintain a substantial atmospheric pressure against the side walls of the plate. The pressure differential may vary widely as desired. depending upon the size of the over-all area of the plate and on the gauge of sheet metal used for the plate side walls. It may, for example, vary within the range of 4 inches or less. of vacuum, to 20 inches or more, of vacuum. The effect of atmospheric pressure against the side walls is to maintain a very close contact between the inner 'faces of the walls and the opposed side faces of the tubing. This pressure difierential results in a heat transfer rate as good as those 'of the metal itself; and far better than the heat transfer conditlon existing where metals are welded, brazed, or soldered together. The procedure is simple, and easily and quickly carried out. The result is a cold plate having very efficient heat transfer characteristics between the refrigerant in the interior of the coil. and the exterior of the plate.

An important function of the rectilinear tubes is to provide an internal reinforcement for the plates. The plates of the type herein shown are frequently in use in freezing presses and are subjected to heavy pressure in order to compact the substances undergoing freezing between adjacent plates. The provision of rectilinear tubes has the double function, in a structural sense, of resisting inward pressure against the side of the plate, and of holding the outer surfaces of the opposite faces or sides of the plate, to true and parallel planes. Thus when the coil structure is positioned within the plate and the plate interior is partly exhausted, the outer pressure of theatmosphere against the walls of the plate maintains the plate as a strong structural element, having substantially true planes at each side, the planes of the outer surfaces of the two sides of the plate being substantially parallel.

This application may be regarded as a continuation in part of co-pending application 571,863 filed January 8, 1945.

g I claim:

1. In a vacuum plate adapted for use in refrigeration, and adapted to resist heavy pressures, a I

some for meintei a partial vac in the space within said walls and about said coil structure su ficient to maintain said walls y pressed against, end in intimate contact with, the opposed generally plane top enci bottom surfaces oi the coil, seici perellei rectilinear duct lengths being suificient in number e being sumciently closely spaced to term a reinforcement for said housing wells, and to maintain the outer surfaces of said housing walls generally plane 2. The structure of claim ii characterized by and including a, eutectic liquid positioned within said plate in the space within said housing and exterior to said coii structure.

3. The structure of claim 1 characterized by w RIEFERZENCES CREE The following references are of record in the s, time of such space.

w file of this patent:

UN STATES PATENTS Number

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