US2059864A - Evaporator device - Google Patents

Description

NOV. 3, 1936. p HEATH 2,059,864

EVAPORATOR DEVICE Filed Sept. 24, 1931 Patented Nov. 3, 1936 UNITEDYSTATES PATENT OFFICE EVAPOBATOR DEVICE Delos P. Heath, Detroit, Mich.

Application September 24, 1981, Serial No. 564,729

/ 2 Claims.

It is an object to provide a new shaped structure and methodsv of assembling structure to form a corrugated receptacle to contain fluids subjected to heat changes, which container is formed by assembling sheet material to form a header space and passageways communicating therewith to permit emcient fluid circulation and greater compactness and strength.

It is an object to provide a sheet metal evaporator enclosing a freezing chamber and having an inner casing corrugated transversely of its elongated gas and liquid header to provide a stronger and a more compact construction having more surface for heat absorption, and a greater area for the passage of refrigerant.

It is an object to'provide a sheet metal evaporator for the expansion of refrigerant comprising two rectangular sheets of metal bent to form a freezing chamber and having their edges continuously contacting and continuously welded together at the front and back of the evaporator, to eliminate the usual gas-liquid header plates and to thus reduce refrigerant leaks and to provide a stronger construction which adapts itself to flame and seam welding.

It is an object to provide at low cost an improved support for sheet metal evaporators;

It is an object to provide an improved header and top walls of an evaporator to provide compactness and a saving of refrigerant.

In the drawing:

Figure 1 is a perspective of part of the outer sheet of the evaporator.

Figure 2 is a perspective of part of the irmer sheet of evaporator.

Figure 3 is a perspective of an end plate.

Figure 4 is a perspective of a perforated end plate. a

Figure 5 is a perspective of an assembly of the inner and outer sheets, to form an evaporator with a freezing chamber.

Figure 6 is a front elevation of a modification of the tank shown in Figure 5.

Figure '7 is a side elevation of Figure 6.

Figure 8 is a front elevation in section of a support through line 2-2 Figure 6, but showing a modification for an outlet fitting.

Figure 9 is a side elevation in section through line 2-4 Figure 6, showing an inlet and outlet fitting.

Like numerals refer to like parts.

I have already shown in my Patent #1,726,486, dated August 27th, 1929, a sheet. metal evaporator enclosing a freezing chamber and having inner' and outer walls formed from single sheets of metal, and with a header space and passageways for refrigerant depending therefrom. But, it is the purpose of this application to disclose certain other improvements in receptacles of this character, which will "allow easier manufacture and more efficient ebullition.

In manufacturing the receptacle, the outer sheet. I, Figure 1, is formed with corrugation, 2, connecting arcuate end header portions, 5, by stamping, rolling, or other process from flat metallic sheets. Inner sheet, 8, Figure 2, is stamped from a second flat metallic sheet to provide centrally located corrugations, 9, and, on opposite sides thereof, with the support corrugations, iii, extending in a direction transverse to the central corrugations, 8.

The inner sheet, 8, is then formed on a roll or brake into a rectangular shape enclosing a space which may be a freezing chamber, as shown in Figure 5. The ends, II, are abutted at the bottom of the chamber and the raised portions of the corrugations l0 and 9 in the sides l6 and in the top H project inwardly. The outer sheet 3 is similarly formed into a rectangular shape to fit over the sheet 8 Figure 5, but the corrugations 2 project outwardly, and the header portions 5 abut one with the other over the chamber 35. The superimposed sheets I and 8 are then clamped in a welding fixture with peripheral portion 1 and flat portions 3 of sheet I in contact with the fiat peripheral portions 1 of sheet 8 and flat portions of 8 intermediate the peripheries. The corrugations! of sheet 8 register with the corrugations 2 of sheet I to provide enlarged refrigerant passageways along the top of chamber 35. Fused means, suchas soldering, brazing or welding is then employed to permanently fasten together contacting portions of inner sheet 8 and outer sheet I and to seal together their contacting peripheries. The ends 5 of sheet I are fused together and the ends H of sheet a are similarly fastened. Substantially semi-circular metallic plates II, l9, Figures 3 and 4 or other shaped plates, are then fused between the sheets i and 8 to close the openings at either 45 end of the header Ii, which is formed by portions of the sheets I and 8. The and i9 has an inlet opening 2| near its base and an outlet opening near its upper portion.

This method of assembling sheets I and 8 with the joints i3 and I! on opposite sides of the chamber is important as it permits the side .wall portionsof i and 8 to contact even though the U bends of I and 8 are slightly imperfect because of inaccurate dies or because of deforma- 55 2 tion of the sheets in handling. Welding material maybeusedat I2 and lltofillanysmallspace that may exist after the sides, top. and bottom are spot or seam welded together.

Figures 6 and 7 show a modification of the structure of Figure 5, wherein the corrugations, 8 which may have raised portions projecting either outwardly or inwardly, are not extended allthewayacrossthetopportionof8,thus simplify l the bending of the side walls, I, oftherectangularshapechamber 85. Alsoas disclosed in my application 528,847 and other pending applications, a large arcuate header portion, 8, is embossed in a central portion of the sheet, I, to eliminate the end plates I8 and I8 andtomakeareasLattheperipheries oftheinnerandoutersheetslandhcontiriuously contacting at both the front and the back edges of the evaporator chamber 85, to facili- -tatesealing,particularlywheniiameor seam welding is employed to fuse the sheets together. Thesmallportionsl alsoformaheader It at the edges of sheet I, below the bottom of the freezing chamber 35.

lnassemblingsheetsland8,tcformthe contacting portions of I, and, 8, may then be fused together at 8 and 1, between the corrugations and at the side peripheries, and the fused the freezing chamber, 85, with the edges, I2, of the innor sheet, 8, abutting each other at the botof the freezing chamber and the edges, l3, outer sheet, I, abuttingeach other over top of the chamber, 35. The final operation would be sealing the edges, I2, together and fussing the edges, I8, together to provide fluid receptacle.

However, it must also be understood that I may first shape the inner corrugated sheet, 8, into the shape, 85, and fuse together the edges, then shape the outer corrugated sheet, 8, to a shape substantially similar to the chamber, 35, and then press the two sleeve like structures thus formed together so that the portions 8 and I, contact, and finally fuse together the contacting portions of 8 and I.

For one means of liquid inlet and gas outlet in the evaporator, I may provide the fitting shown in Figure 9. This fitting comprises a cup shape body, 22, having the inlet opening, 2|, and the outlet opening, 20, and the pipe, 24, fitted to the outlet. 'lhe screen, 23, closes the opening to the cup, 22, to prevent injurious matter entering the outlet. The body, 22, is welded to an opening in one end of the header, I5.

An improved evaporator support, 25, Figures 6,7,and8,'isdrawnfromsheetmetalinthe cup. The sides of the cup, 28, may and its bottom may be slightly conarcuate to conform to the arcuate of the header, I8. The flanges, 28, of the support, 25, may be drilled with holes or cut of a nical and with the slots, 21, Figure 8, to receive supportint bolts or screws. However, when this form of support is employed with evaporators removable as units with plates and a portion of the heat insulation of the refrigerator food chamber, I prefer to draw one or more supports, 28, in the plate, 32. shown in dotted lines in Figure I.

To avoid the difllculties now experienced in baking vitreous porcelain over heavy welds or brazing at the support I prefer to weld-the support from the inside of the header, II. To accomplish this it is practical to spot weld the bottom of cup, 25, to the top of header, I5. However a better method is to perforate the bottom of cup, 25, and the top of header, II, to receive the small diameter end, 2!, of the conduit bushing, 28, Figure 8, and to interiorly fuse the header wall of I5, fluid tight to the end, 28. Both inlet, 2|, and outlet, 28, may be thus arranged thru one or more bushings 28, and one or more cup shaped supports 2!.-

As the walls of 25 and I5 are approximately the same thickness porcelain enameling of clean appearance results. The end, 28, m y be expanded over I5 before being sealed to the header wall, thus retaining cup, 25, rigidly between the shoulder formed on bushing, 28, and wall, I5. Because of the cylindical concavity of the bottom of cup, 25, the support can not turn on its axis.

The assembly of the support, 25, as shown in Figure 8, may be done before sheet I, is fastened to sheet, 8. I

Heat transforming trays, 83, Figure 8, may contact bottom, II, or the support corrugations, III.

In operation heat transferred through the walls I and 8, causes fluids within the headers and corrugations to change their physical state.

As a condenser the header, I8, Figure 1, would be provided with\ the outlet, 84, for liquid and with the inlet, 28, for gas.

Operating as a refrigerant evaporator of the fiooded type, liquid refrigerant admitted into header, I5, through opening, 2|, fills passages formed by corrugations 2, 8, and III, in Figure 5, and also header, ll, in Figure 6 and 7, and part of the header space, I5. When the refrigerant pump sucks gas from the gas space within header, I 5, to change evaporator pressure or,

when additional heat passes through the walls I and 8, some of the liquid refrigerant boils to a gas, thus removing heat from the walls of thei expansion chamber formed between sheets I an 8.

Warm air passing over the outside of sheet, I, and over the inside of sheet, 8, transfers its heat to the evaporator. Also the ice pans such as 32 Figure 6, within the freezing chamber, 35, and in contact with sheet 8, rapidly transfer heat from the water or other matter contained in the trays to the refrigerant. This heat is conveyed by the refrigerant gas outside of the heat insulation of the refrigerator.

It will be noted that the substantially flat corrugated top of the freezing chamber, 85, allows;ice trays to be mounted close up to the top portion of the sheet 8, and thus conserves space. The plurality of corrugations, 8, in that portion of sheet 8 forming a wall portion of header, I5, not only acts to prevent deformation of sheet, 8, under pressure but may also in Fig. 5 serve as liquid refrigerant feeding passages to side wall corrugations, 2. Thus gas bubbles rising and enlarging in the side wall passages. 2, enter the enlarged top wall passages formed by corrugations 6 and 8 and therefore better ebullition conditions result.

To further assist circulation within the evaporator and to facilitate the separation of gas and liquid, I may form each of the corrugations, 8, as shown in Figures 8 and 'I, with varying depth in the vertical plane that their cross sectional areas may increase as these passage ways, 8, approach and enter the header I5.

Other advantages of my sheet metal evaporator include ease of welding the sheets I and 8, together near the header II. Also the usual circular drum header, with ducts depending at the drum side walls, maintains a stagnant pool of liquid refrigerant of considerable depth below the inlet from the drum to the ducts. This pool is eliminated by the structureof Figure and an evaporator of this type operates with a greatly reduced charge of refrigerant as eiliciently as do the circular drum type with their larger amount 'of liquid refrigerant. Thus there is effected a considerable savings in cost and the hazard to human life residing in the household refrigerating units employing evaporators is greatly reduced.

I have shown in the drawing and disclosed above certain specific shapes of freezing chambers and side wall structures for heat transferring receptacles, but I do not wish to limit myself and desire to claim all uses for the invention to which it appertains.

I claim:

1. An evaporator for a refrigerating system comprising, superimposed sheet metal portions formed to provide double walls of an elongated horizontally disposed sharp freezing compartment, the outer sheet metal portion of the double walls having a part thereof bulged outwardly from the wall to form a chamber or manifold extending longitudinally with the freezing compartment at the top of the evaporator, the inner sheet metal portion of the double walls including a part extending continuously across the bottom of the legs of the outwardly bulged part of said outer sheet metal portion forming said chamber or manifold to provide said freezing compartment with a substantially flat inner wall surface adiacent said chamber or manifold, said inner and said outer sheet metal portions of the double walls being secured together at certain points and spaced apart at certain other points to provide refrigerant passages therebetween communicating with said header or manifold, said inner sheet metal portion of the double wall being corrugated in a direction transverse to the axis of said header or manifold at least throughout a part thereof extending between the legs of the outwardly bulged part of the outer sheet metal portion for structural strength, a cupshaped sheet metal member having the bottom thereof formed to conform to the contour of the outer wall of said header or manifold and secured thereto for suspendingly supporting said evaporator, said bottom of said evaporator sup port being perforated and that portion of the header or manifold wall registering with said support bottom being also perforated, and conduit means extending through said perforations and communicating with the interior of said header or manifold, said conduit means being arranged to form the point of security of said cupshaped member to said evaporator.

2. An evaporator for a refrigerating system comprising, superimposed sheet metal portions having parts thereof secured together at certain points and other parts thereof spaced apart at certain other points to provide a double wall having refrigerant passages therebetween, said double wall being formed to provide a plurality of walls of a sharp freezing compartment, the outer sheet metal portion of the double wall having a part thereof bulged outwardly at the top of the evaporator beyond the parts thereof spaced from the inner sheet metal portion and forming a chamber or manifold communicating with said refrigerant passages, and a cup-shaped member having the bottom thereof formed to conform to the contour of the outwardly bulged wall of said header or manifold and secured thereto to form a support for suspendingly supporting said evaporator.

' DELOB P. HEATH.

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