US2776549A - Refrigeration compartment - Google Patents

Description

Jan. 8, 1957 R. E. GERHARDT REFRIGERATION COMPARTMENT 5 Sheets-Sheet 3 IN VEN TOR. RICHARD E. GERHARDT ATTORNEY Filed Nov. 24, 1954 United States Patent ce REFRIGERATION COMPARTMENT Richard Edward Gerhardt, Clarksv ille, Ind., assignor to Reynolds Metals Company, Louisville, Ky., a corporation of Delaware Application November 24, 1954, Serial No. 470,959

6 Claims. (Cl. 62-126) The present invention relates to an improved one piece freezing compartment of the type employed in household refrigerators. r

It has been proposed to construct a freezer compartment for a refrigerator in which a vertical wall, usually the back wall carries a separate receiver or reservoir for liquid refrigerant and an accumulator chamber, which may be attached to the wall, and which are connected by suitable tubing to the inlet and outlet ends of the evaporator. This construction involves forming at least four tube connections, namely, one to the reservoir inlet; one between the reservoir and evaporator inlet; one between the accumulator and evaporator outlet; and one to the accumulator outlet. Such joints involve not only the expense of manufacture, but entail also, the expense of in: spection and possibility of leakage. Elimination of joints in the refrigerant system therefore is highly desirable.

In addition the reservoir and accumulator must Withstand internal pressure and must have t-hin walls to pro vide good heat conductivity, so they are generally made in cylindrical form. Such a structure offers a small wall area compared to the cubic content, and the attachment of a cylindrical body to the flat surface of the freezer compartment involves contact of limited heat exchange areas, so that heat transfer is greatly limited.

It is an object of the present invention to provide a freezing compartment made from a single sheet blank having protuberant wall portions providing receiver, evaporator and accumulator chambers within the walls of the compartment, and protuberant flow connections forming an integral part of the blank.

A further object is the provision of a unitary freezing compartment which provides a protuberant accumulator and receiver in one panel or vertical wall thereof.

A further object is the provision of a freezing compartment constructed to provide a protuberant accumulator and receiver having a relatively large heat exchalnge surface area as an integral part of the vertical wa A further object is the provision of a freezer compartment having increased efficiency and which can be manufactured at a reduced cost.

It has been proposed to produce a unitary freezing compartment in one piece from a flat blank prepared by roll bonding together two sheets of metal with a resist therebetween to prevent bonding of the sheets over certain areas defining the evaporator chamber, and then expanding or dilating the unbonded areas by internal fluid pressure to provide a protuberant evaporator chamber between the sheets forming the blank. According to the present invention, a flat blank is so formed as to provide for bending it into a tubular or tunnel form incorporating a protuberant evaporator chamber, and with an integral end wall which incorporates protuberant reservoir and accumulator chambers between the sheets forming the end wall.

By forming the back wall section containing the reser- 1776,549 Fatented Jan. 8, CW5? voir and accumulator chambers integral with the part of the blank constituting the tubular freezing compartment it becomes unnecessary to provide separate joining tubes between these chambers and the evaporator, and connecting protuberant conduits can be formed in the blank in the roll bonding and expansion operations, so I that the only tubular joints that need be made are the connections from the system to the reservoir inlet and to the accumulator outlet. Also, by forming the reservoir and accumulator chambers in the end wall with a large ratio of wall surface to volume, the temperature effect of evaporation which occurs in said chambers, is utilized efficiently in providing a low temperature in the freezing compartment. These chambers are constructed relatively thin in horizontal cross section so as to present a high ratio of heat transfer surface to volume of contents, and'the blank provides depressed bonded areas at spaced intervals within the confines of the chambers so that the thin walls are reenforced to withstand the internal pressure without substantial bulging. The overall result is that the manufacture is simplified, the cost is reduced, and the efficiency of operation is improved.

The invention will be described in greater detail in the following specification taken in connection with the accompanying drawing showing a preferred embodiment by way of example, and wherein:

Figure 1 is a top perspective view of the refrigerator compartment as seen from the rear;

Figure 2 is a rear elevational view;

Figure 3 is an elevational view of one side;

Figure 4 is an elevational view of the other side;

Figure 5 is a plan view;

Figure 6 is a plan view of the blank ready to be bent to shape;

Figure 7 is a section taken on line VII-VII of Figure Figure 8 is a section taken on line VIlI-VIII of' erating compartment is of tubular form and comprises a horizontal bottom wall 1, vertical side walls 2, 3, a horizontal top wall 4, and a vertical end wall 5. The T-shaped blank from which this compartment is made is shown in Figure 6, and the compartment is formed by bending the T-shaped blank, the double dot and dash lines 6, 7, 8, 9 and 10 showing :the general limits of the curve or fillet at which the blank is to be bent. The bottom 1 of the compartment is defined in the blank by edge 11 and dot and dash lines 6, 8 and one side 2 is defined in the blank by edges 11, 12 and the dot and dash lines 9, 10; the other side 3 is defined by edges 11, 13 and the dot and dash lines 7, 8; and the end is defined by edges 14, 15, 16 and the dot and dash lines 6. Edge 11 is hemmed, and edges 14, 15 and 16 are provided with flange or tab portions 17, 18 and 19. In forming the compartment, edges 21 and 22 of the head of the T are united at the middle of the top, as by riveting (Figure 5), preferably in lapped relation, so that the top is defined in the blank by edges 11, 12, 13 and the dot and dash lines 7 and 10. Thus, the end wall 5 is formed from the leg of the T, and the'bottom, side walls and top are formed from the head of the T.

The blank preferably is made by roll bonding together a pair of sheets A, B indicated by dot and dash lines in Figure 7, of aluminum or other suitable metal with a resist therebetween. In the roll bonding operation the blank in heated condition is passed between pressure rolls to effect a reduction in thickness and an elongation in the direction of rolling with substantially no increase in Width, so that the sheets are caused to adhere or bond together in all areas of contact not protected by the resist. The

r.) unbonded areas then are dilated by fluid pressure to pro vi-de the various protuberant chambers-and passageways or conduits which will now be described.

Referring to Figure 6, the dilated plate provides a series of protuberant return bends 26 along edge 21; and a series of protuberant return bends 27 adjacent the dot and dash lines 9 (which may be regarded as a prolongation or extrapolation of edge 14), and these return bends are joined by protuberant straight runs 28 so as to provide a sinuous main tubular evaporator chamber. It will be noted that when the blank is bent to sha e (Fig. 2) the protuberant evaporator chamber will extend from the bends 27 adjacent one fillet edge 9 of the bottom, along the bottom and around fillet edge 3 and up side 3, around fillet edge 7 and across the top 4 to the middle Where bends 26 will be located. The inlet to the evaporator is through a protuberant conduit 29 in the end wall 5, this conduit continuing unbroken by crossing the fillet edge 6, bottom 1 and fillet edge 3, and continuing to its connection with the first return bend 26 of the evaporator.

The end wall provides a protuberant receiver chamber 31 for liquid refrigerant. Referring to Figure 9, it will be noted the walls of the sheets A and B are bonded together in patches 32, and the areas around the patches are dilated. The patches provide a reinforcement to resist the pressure within the receiver chamber. The conduit 29 makes a reverse bend 33 and extends down the end wall at 34 and by a bend 35 across the bottom at 36 between the receiver chamber and the lower edge 6 of the end wall, where it connects at 37 with the receiver chamber near the bottom, and it also connects with the receiver chamber at 38 near the top. The connection 38 at the top preferably is restricted by an indentation 39 for-med in the roll bonding. The bottom connection 37 insures that the reservoir be filled with liquid refrigerant before liquid is fed to the evaporator, and the top and bottom connections insure that during the defrosting cycle the liquid refrigerant inthe receiver is rapidly discharged by the hot gas into the evaporator.

The side Wall 2 has a series of protuberant return bends 41 near its bottom (that is, near the fillet edge 9), and a series of runs 42 extend up the side wall 2, around fillet edge and across the top wall 4, and connect with a series of protuberant return bends 43 near the middle of the top. This portion of the structure provides an auxiliary evaporator and is connected to the main evaporator through the long conduit 44 which extends between the last bend 26 of the main evaporator and the first bend .43 of the auxiliary evaporator. It will be understood that the provision of two evaporators is optional, and if desired a single evaporator chamber may be formed by having the runs 42 form a continuation of runs 28 with omission of return bends 27 and 41.

The accumulator chamber 45 in end wall 5 is constructed similar to reservoir chamber 31 with similar reenforcing patches 32, and the last run 46 of the evaporator continues along top 4- around fillet edge 10, down wall 2 and around fillet edge 9 and along the bottom, makes a bend at 47 and continues around fillet edge 6 to join the accumulator chamber at 48 at the bottom. An inlet passage 49 connects to the top of the reservoir 31 and an outlet passage 51 connects to the top of the accumulator 45, these passages having tubes 52 and 53 respectively connected thereto by welding, or any other desired way. Tube 52 connects to the condenser of the refrigerating system and tube 53 connects to the compressor inlet. Tube 52 also connects to the compressor outlet in known manner for supplying hot gas to the evaporator during the defrosting stage. As these connections do not form part of the present invention and are known, they are not illustrated. If desired, perforations 54 may be formed in the back wall 5 to reduce heat transfer between the reservoir and accumulator.

The operation now will be explained. In the freezing phase, assuming the evaporator is dry (a condition not ordinarily encountered in this apparatus) liquid refrigerant will not be supplied to the evaporator coils until the receiver 31 is filled, because of the standpipe action of the bend 33 between conduits 36, 29. In operation the receiver tends to level out the flow of liquid refrigerant to the evaporator, as is understood in the art. The relatively thin receiver chamber has a large wall surface compared to its horizontal cross section, and as approximately half of the receiver Wall has an inside exposure, evaporation that occurs in the receiver will assist in taking away heat from the interior of the freezing compartment.

In the defrosting cycle, the hot gasenters the receiver chamber 31 at the top through conduit 49, and because of the restriction 39 the liquid refrigerant is rapidly discharged through conduit 36, 29 into the evaporator at the same time that it is mixed with and heated by hot gas flowing through restriction 39. The compartment thus is rapidly thawed or defrosted. At the end of the defrosting cycle there will be a quantity of warm liquid refrigerant in the evaporator chambers, which commences to evaporate when the compartment is returned to the refrigeration phase. Thus, cooling in the evaporator is taking place while liquid refrigerant is being supplied to the receiver, and the liquid in the receiver can absorb heat from the compartment to increase the cooling rate at the beginning of the freezing phase, so the compartment is rapidly cooled. Also, liquid remaining in the accumulator will absorb heat from the compartment and increase the cooling rate therein. As the accumulator chamber also has a relatively large wall surface compared to its volume, approximately half of its wall area is exposed to the interior of the refrigerator compartment, and a good heat transfer is effected.

The receiver chamber 31 and accumulator chamber 45 are an integral part of the wall 5 of the freezer compartment, and the connections 29, 46 with the ends of the evaporator to the reservoir and accumulator are also an integral part of the walls of the freezer compartment, so that the only joints that need be made are where the tubes 52 and 53 join the conduits 49 and 51 in the wall 5. This eliminates expense and reduces the difliculty of manufacture by reducing the number of tube connections that have to be made, and as above explained the construction improves the efficiency of operation of the refrigerator.

I claim as my invention:

1. A refrigerator compartment comprising: a body comprising a pair of integrally bonded fiat metal sheets providing certain unbonded protuberant areas therebetween as hereinafter defined; said bonded structure be ng bent to form a refrigeration tunnel compartment having an integral vertical end wall joined to the tunnel portion through a bend; said tunnel portion wall having unbonded protuberant areas forming an evaporator chamber for refrigerant; and said end wall having an unbonded protuberant area forming a reservoir for liquid refrigerant; and an unbonded protuberant area forming a first passageway connected adjacent the bottom of said reservoir and extending upwardly along said Wall to a point adjacent the top of said reservoir, then around the bend joining the end wall to said tunnel portion, to connect integrally to said evaporator chamber.

2. A refrigerator compartment as specified in claim I having: a second passageway connected adjacent the top of said reservoir, and extending to and joining said first passageway adjacent the top of. said reservoir.

3. A refrigerator compartment as specified in claim 1 wherein: said evaporator chamber comprises two sections connected serially; one section comprising a first series of return bends near the middle of the top wal with a series of passageways extending from said return bends horizontally in said top wall to one side wall and vertically down said one side wall and horizontally along said bottom to a second series of return bends in the bottom adjacent the other side wall to form a sinuous evaporator chamber; and said other section comprises a third series of return bends adjacent the bottom on said other side wall with a second series of passageways extending from said latter return bends vertically upward along said other side wall and horizontally along said top wall to a fourth series of return bends near the middle of said top wall, to form a second sinuous evaporator chamber.

4. A refrigerator compartment as specified in claim 1 wherein said reservoir has its walls oppositely depressed in areas and the oppositely depressed areas are bonded together to form inter-connected cells between the bonded areas in the reservoir.

5. A refrigerator compartment comprising: a body comprising a pair of integrally bonded flat metal sheets providing certain unbonded protuberant areas therebetween as hereinafter defined; said bonded structure being bent to form a refrigeration tunnel compartment having an integral vertical end wall joined to the tunnel portion through a bend; said tunnel portion walls having unbonded protuberant areas forming an evaporator chamber for refrigerant; and said end wall having an unbonded protuberant area forming a reservoir for liquid refrigerant; and an unbonded protuberant area forming a first passageway connected adjacent the bottom of said reservoir extending along the end wall to the top of said reservoir then by a return bend vertically down said end wall and around the bend of the end wall to connect integrally to said evaporator chamber; and a restricted passageway connecting the top of said reservoir to said first passageway adjacent said return bend.

6. A refrigerator compartment comprising: a body comprising a pair of integrally bonded flat metal sheets providing certain unbonded protuberant areas therebetween as hereinafter defined; said bonded structure being bent to form a refrigeration tunnel compartment having an integral vertical end wall joined to the tunnel portion through a bend; said tunnel portion walls having unbonded protuberant areas forming an evaporator chamber for refrigerant; and said end wall having an unbonded protuberant area forming a reservoir for liquid refrigerant; and an unbonded protuberant area forming a first passageway connected adjacent the bottom of said reservoir and along said end wall and connecting through the bend of the end wall integrally to said evaporator chamber; and said end wall provides an accumulator chamber formed by unbonded protuberant areas connected by a third unbonded protuberant passageway area extending along said end Wall and connecting integrally in the bend of the end wall to the discharge end of said evaporator chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,162,586 Newman June 13, 1937 2,469,828 Johnson May 10, 1949 2,663,999 Alsing Dec. 29, 1953 2,672,022 Jacobs Mar. 16, 1954 2,680,353 Baxter June 8, 1954

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