US2903863A

US2903863A - Heat transfer unit

Info

Publication number: US2903863A
Application number: US612247A
Authority: US
Inventors: Donald L Coning
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1956-09-26
Filing date: 1956-09-26
Publication date: 1959-09-15
Anticipated expiration: 1976-09-15

Description

Sept. 15, 1959 D. L. CONING HEAT TRANSFER UNIT 2 Sheets-Sheet 1 Filed Sept. 26. 1956 INVENTOR.

Donald L. Con/fig BY g His Attorney D. L. CONING HEAT TRANSFER UNIT Sept. 15, 1959 2,903,863

Fil ed Sept. 26. 1956 2 Sheets-Sheet 2 INVENTOR.

Don a/a' L. Con/n9 BY 6 g 4 His Attorney United Patent 7* i HEAT TRANSFER UNIT Donald-1L. Coning, New Lebanon, Ohio, assignor to General' Motors Corporation, Detroit, Mich, acorporation of Delaware Application September 26; 1956, Serial No. 612,247 I 1 Claim. (Cl. 62289) This inventionrelates to a refrigerating apparatus and,

more particularly to plate-type evaporators haying liquid catching means at one edge.

As shown in the Jacobs et a1. Patent 2,672,023 issued March 16, 1954, catch troughsfsuch as the catch trough 7 0' have been provided beneath plate evaporators. Such; troughs are somewhat expensivenotonly becauseofthe cost of the trough itself but also in the cost; of assembling it into. the refrigerantfcabinet. Such troughs also reduce the amount of usable space within the; cabinet.

These and-otherobjects are obtained in the form shown,

in the drawings, in which a: plate is bonded together except along one edge and except where refrigerant passages are desired'by a roll bonding andhydraulic expansion process such as is described'j in the Long. Patent 2,662,273 issued" December 15, 1953. edge is separated by a knife edge and the two, portions are bent outwardly and upwardly to form the liquid catching groove or trough. For gravity air flow the trough or groove will normally be placed at the bottom but for forced air flow the trough or groove may be placed in the trailing edge of the evaporator or heat exchange no matter whether this edge is at the bottom, top, or sides.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a diagrammatic view of a refrigerator embodying one form of my evaporator;

Figure 2 is a plan view of one of the sheet portions of the evaporator plate after stop weld material has been applied thereto;

Figure 3 is a diagrammatic view in elevation showing another sheet superimposed upon the one shown in Figure 2 undergoing roll bonding; 0

Figure 4 is a diagrammatic view in elevation showing the plate after roll bonding with the one edge split by a knife edge and in the process of having the bifurcations bent through about to form integral troughs on either side;

Figure 5 is a front view showing the evaporator plate after the hydraulical expansion of the refrigerant passages;

Figure 6 is an end view of Figure 5;

Figure 7 is a fragmentary front .view showing a spout attached to one end portion of these troughs;

Figure 8 is an end view of the portion of the evaporator shown in Figure 7;

The nongbonded; 40

2,993,863 Patented Sept. 15, 1959 Figure 9 is a modified plan view of a sheet portion provided with stop weld material;

Figure 10 is a diagrammatic view in elevation showing another sheet superimposed upon the one shown in Figure 9 undergoing the roll bonding;

Figure 11 is a view in elevation diagrammatically showing the method of slitting the lower edge after the lower edge has been. hydraulically expanded;

' Figure 12 is an end view of Figure 11;

Figure 13 is a fragmentary view illustrating the fiattening of the bifurcations of the lower edge shown in Figures 11 and 12; and

Figure 14 is a view illustrating the bending of the bifurcations shown in Figure 13 into the form of a trough.

Referring. now to Figure 1 there is shown diagrammatically a. refrigerator cabinet 20 having insulated walls enclosing an upper freezing compartment 22, an above freezing foodstorage compartment '24 with an insulated Wall '26vdividing the two compartments. Beneath the food storage compartment 24 there is also provided a machine compartment 28, containing a sealed motor-compressor unit 30 and a condenser 32. The. condenser 32 is connected by a capillary tube 34 to the upper portion of a U -shaped freezing evaporator 36 locatedin the freezing compartment '22. The opposite upper portion of the evaporator. 36, is connected by a conduit 38 to the upper rightfcorner of a plate-type evaporator 40. The evaporatorAll has refrigerant passages 59 formed therein by the roll bonding Processes illustrated in Figures 2 to 14. The, outlet of, these refrigerant passages is connected by the suction conduit 42 to the suction entrance of the sealed mqtoncornpressor unit 30. The capillary tube 34 and the suction conduit 42 are preferably bonded together to serve as a heat exchanger between the compressed refrigerant and; the evaporated refrigerant. The refrigerating system preferably is controlled by a snap acting thermostatic switch 44. connected in series with motor-compressor unit 30 andcontrolled by a thermostatic bulb 46 mounted upon the lower portion of evaporator 40. This switch 44 is preferably adjusted to operate on a defrosting cycle so that frost accumulates during the running periods upon the plate evaporator 40 and melts therefrom during the off cycle.

According to this invention to catch condensate or frost melting therefrom, the plate evaporator 40 is provided with integral liquid catching troughs 48 which are formed from the bifurcations extending along the bottom edge of the evaporator 40. The bifurcations extend in opposite directions outwardly and upwardly into the form of a hook shape to serve as troughs or other forms of liquid catching devices. To one end of these troughs is attached a spout 50 which discharges into the drain tube 52 extending into the machine compartment 28 for discharging melted frost into an open-topped receptacle provided upon the top of the sealed motor-compressor unit 30. Either the entire plate 40 or the troughs 48 alone are preferably provided with a slight slant or fall toward the spout 50 to assist in the gravity flow of the collected liquid to the spout. This moisture is heated in the receptacle 54 by waste heat dissipated by the motor-compressor unit 30 and caused to evaporate.

The plate type evaporator 40 is preferably formed by the roll bonding process described in the aforementioned Long Patent 2,662,273 issued December 15, 1953. In

5 this roll bonding process, stop weld material is applied which have been applied by the roll bonding process illustrated in Figure 3 and described in further detail in the aforementioned Patent 2,662,273. After the roll bonding has taken place producing a forge weld between sheets except where the stop weld material is applied, the one edge of the bonded plate is separated by a knife edge 64 in the vicinity of the stop weld material 60. This is permitted by the stop weld material 60 which slit by forcing it onto a cutting or splitting tool or knife separates the

bifurcations

66 and 68. Two

removable metal rods

70 and 72 are provided adjacent each other just above the knife edge 64. These are located on opposite sides of the

forge weld sheets

56 and 62. The stop welded sheets are bent approximately 180 in either direction over either of the

rods

70 and 72 to form the drain troughs with the other rod being temporarily removed. After this, the sheets may be hydraulically separated and expanded in the area of the stop weld material 58 between flat dies in the manner shown in the aforementioned Long Patent 2,662,273 to form a continuous passage 59. Then the upper edge may be trimmed exposing both ends of the passage 59 formed in this manner.

The upper edge may be trimmed to complete the plate evaporator 40 proper as shown in Figures 1, 5 and 6. After this, there is attached a short sheet metal spout 50 which envelops one end of the troughs and has upper inwardly turned supporting

edges

76 and 78 which book over the edges of the

troughs

80 and 82.

Liquid catching in the troughs 48 flows from the spoutv 50 into the drain tube 52 which discharges the moisture into the receptacle 54 in the machine compartment 28.

In Figures 9 to 14, a modified form of the invention is shown in which the sheet 156 has a stop weld material 158 to form a refrigerant passage 159 similar to.

the refrigerant passage 59 for the plate evaporator 56. However, stop weld material 160 instead of being applied to and including the lower edge is spaced from the lower edge as shown in Figure 9. Another sheet portion is superimposed upon the sheet portion 156 and the two are roll bonded together as shown in Figure 10. The lower edge becomes bonded together. The portions between the sheets containing the stop weld material are hydraulically expanded. This forms a tubular shape adja cent the lower edge of the sheet 156 as shown in Figures 11 to 14. This is hydraulically expanded into a tubular shape 148. Thereafter this lower tubular edge 148 is 149 as illustrated in Figures 11 and 12. The lower edge of the plate is then forced over another knife 164.

The tubular portion is then flattened onto the knife edge 164 by the squeezing elements onto the sides of the knife edge 164. The plate evaporator 140 is then placed in a tool having the knife edge 64 and the

removable rods

70 and 72 as shown in Figure 4. Then the plate 140 is bent approximately over either of the

rods

70 and 72 in opposite directions to form oppositely extending lower troughs 148. During this bending the alternate rod is removed. These troughs may be used either when the evaporators 40 or 140 are operated on a defrost cycle or operated at above freezing temperatures. The method of manufacture is inexpensive and provides a compact integral trough on either side of the lower edge of the plate. The melted frost flows readily through the troughs and the spout 50 into the tube 52.

When the plate evaporators 40 or 140 are placed in a forced air stream the

troughs

48 or 148 are positioned at the trailing edge no matter what the direction of flow.

While the form of embodiment of the invention asi herein disclosed constitutes a preferred form, it is to bel understood that other forms might be adopted, as may come within the scope of the claim which follows.

What is claimed is as follows:

A heat transfer unit including an upright metal plate composed of two metal sheet portions bonded together in some areas to form a unitary plate and separated in other areas to form a fluid passage, the sheet portions at one edge of said plate being separated and extending in a hook shape away from each to form liquid catching surfaces protruding from opposite sides of said plate, and a spout including a U shaped portion having upper turned in portions extending over and engaging the outer I edges of the hook shaped extensions.

References Cited in the file of this patent UNITED STATES PATENTS