US2138525A - Evaporator - Google Patents

Description

Nov. 29, 1938.

W. W. HIGHAM ET AL EVAPORATOR 3 Sheets-Sheet 1 Filed June 29, 1936 S m V fix MyW Z ATTORNEY.

Nov. 29, 1938. w. w. HIGHAM AL EVAP ORAT OR Filed June 29, 1956, 3 Sheets-Sheet 2 Mr W j 3 m fi 7. W x A M rm 1 I M 'f 2 0 BY sfa/v/ey HMO/P56. 76%, m, $00 M;

ATTORNEY.

Patented Nov. 29, 1938 Morse, Dearborn, Mich assignors to Universal Cooler Corporation, Detroit, Mich, a. corporation .of Michigan Application June 29, 1936, Serial No. 87,828

2?. Claims.

An evaporator or heat exchange unit of a refrigerator constitutes the subject matter of this invention. As is well known to those versed in the art, such a device is a unitin which liquid refrigerant may change into gaseous form, thus absorbing heat to cool a compartment in which the evaporator is located.

The objects of the invention are to provide an improved evaporator structure having a highly efiicient heat transfer function, so constructed that a minimum number of operations are required in itsmanufacture, and which advantageously may embody an economical amount of total metal mass. To these ends the evaporator is preferably formed from extruded metal stock which is of hollow form, and this structure is fashioned into proper shape to form an evaporator. Upon fashioning of the stock into an evaporator the same is substantially completed, and thus the number of operations are minimized over such evaporators which may be fabricated from tubing and sheet metal parts. The extruded metal is of a dense nature and the cross sectional thickness may be less than an evaporator of cast metal, and in this regard an economical amount of metal is used. The metal from which the evaporator is made may be copper, copper alloy, aluminum or a suitable aluminum alloy such as duralumin, and preferably aluminum or aluminum alloy, or any other metal capable of being extruded satisfactorily. Such a metalis likely to be somewhat porous when cast, and therefore a casting should have relatively thick walls defining the hollow form for the refrigerant; but such metal is densifled in the extrusion process so a relatively thin wall may be used. This, of course, reduces the cost from the standpoint of the amount of metal used, and facilitates heat transfer through the metal.

In the accompanying drawings:

Fig. 1 is a top plan view of an evaporator constructed in accordance with the invention.

Fig. 2 is a side elevational view with one portion cut away illustrating a section substantially on line 22 of Fig. 1.

' Fig. 3 is a-front elevational view of the evaporator.

Fig. 4 is an enlarged cross sectional view taken substantially on line 44 of Fig. 3.

Fig. 5 is a top plan view of a modified form of the invention.

Fig. 6 is an enlarged cross sectional view show ing a modified form of the extruded shape.

Fig. 7 is a detail view illustrating a structural formation used in the form shown in Figs. 1 to 4 inclusive.

Fig. 8 is a top view with some parts shown in section, illustrating a further modified form of the invention.

Fig. 9 is a side elevational view of the form shown in Fig. 8.

Fig. 10 is an enlarged cross sectional view, 11- lustrating a seam or joint structure for the form shown in Fig. 8.

Fig. 11 is an enlarged cross sectional view illustrating another form of joint or seam structurea Referring first to Fig. 4: The extruded form is shown in cross section in this View. Such a 15 form, as shown, has a hollow formation or tube formation I with oppositely disposed flanges. One flange is shown at 2 and another is shown at 3. It will be observed that one flange, as for example, the flange 3, is located flush with one go side of the tubular form 8, and this side may be substantially flat as shown at 1. The flange'2 is offset or elevated a distance substantially equal to the thickness of the flange 3. Now this form or extruded shape may be extruded in substantially continuous lengths; and in forming the evaporator unit shown in Figs. 1, 2- and 3, the flanges 2 and 3 are cut away from the tubular form at properly spaced intervals as illustrated in Fig. '7.

In the making of an evaporator from this stock, an extruded form of suitable length may be taken, and in addition to the cutting away of the flanges at spaced locations, as shownin Fig. 7, the flanges may be removed from the extreme end portions of the tube. As shown in Figs. 1 and 2 one end portion is illustrated at 5 and another at 6.. The stock is wound into form in helical fashion, although the form shown in Figs. 1 to 4 is not a true helical winding. The 40 first convolution extends throughout almost 360, but the winding is preferably in a plane which is perpendicular to the ,axis. The edge portions of the flanges where they are cut away are brought into substantially facing relation but spaced apart, as shown in Fig. 1. At this location the tube part i, from which the flanges are removed, is fashioned angularly as shown at 1 into the plane of the next convolution. The 50 flanged portion of the tube is now formed into a second convolution, with the flanges 2 and 3 overlapping, as illustrated in Fig. 4. Then the next part of the tube l with the flanges removed is fashioned angularly into the plane of the third convolution. This process continues until an evaporator of the desired length is provided.

It is thought to be preferred that the overlapping flanges should be secured together to keep the seams tight for various purposes, among which or other control is to be attached thereto for admitting refrigerant into the evaporator. The outlet for the gassified refrigerant is through the fitting 9. I

The flanges appearing at the ends of the evaporator may be fashioned or turned outward 1y to provide end flange portions ii and [12. It will be apparent by reference to Fig. 3 that the overlapping flanges provide a wall for defining a compartment which may be used for sharp freezing purposes. However, this wall is broken, as shown in Fig. 1, where the flanges are removed and the tube fashioned angularly. In order to close this opening in the wall a strip of sheet metal l5 (Fig. 3) may be located within the compartment and may be spot welded to the flanges as at Hi. This strip preferably extends the length of the evaporator, and at the rear end is fashioned through a right angle and has a downwardly extending portion l1. Trays or the like are designed to be slipped into the compartment from the front or left side, as Figs. 1 and 2 are viewed, and may strike against the portion I! of the plate. This portion of the plate may be corrugated as at l8 for reenforcing the same. The extreme end of the plate is preferably fashioned so as to extend under the flange at the rear as shown at H], and the flange portion I2 may be cut away to accommodate the flange portion IS. The portion I9 may be spot welded to. the end flange as at 20. The fitting l may be mounted upon this portion ll of the plate in a suitable manner, as for example by rivets 2|.

The compartment within the evaporator may be provided with one or more shelves here shown as a sheet metal shelf member 23 with upturned edges 24 secured to the overlapping flanges 2 and 3 as by means of rivets 25. If desired a. direct cooling action may be had on this shelf; for this purpose a tube 26 maybe connected into the fitting Ill and ;it may extend along one wall of the evaporator underneath the shelf,

and then across the evaporator at the front,

and then along the opposite wall of the evaporator, underneath the shelf, to the rear of the evaporator and with its opposite end connected into the end of the coil. For the purpose of holding'the tube in place there may be a. number of struck-out portions forming teats 30. As shown,in Fig. 4, these struck-out portions are formed in the inner of the overlapping flanges, or in other words, the flange 3. This may be done as the evaporator is being formed, and after the teat is fashioned the flange 2 covers the hollow side thereof, thus providing a smooth exterior.

The evaporator is to be suitably mounted in a refrigerator cabinet or the like, and for this purpose brackets are provided. One manner of providing brackets and one bracket structure is as follows: A sheet metal member 35 havin upstanding side walls 32 is fashioned to provide a lower portion of corrugated form to fit over the exterior tube formation of the evaporator, and to be secured thereto by rivets 34 passing through overlapping flanges 2 and 3. The corrugated form preferably tapers off into the upright portions 33 as at 3b, and this form serves to reenforce and strengthen this sheet metal member. Opposite edges may be flanged as shown at M. This member may be of relatively light stock, and a heavier piece of strap metal, as shown at 338, may have its ends arranged to be received within the flange portions of the plate, and held thereto by rivets 39. This strap metal member extends across the evaporator and may be provided with one or more apertures Gt! for the reception of suitable securing bolts or the like. There are preferably two of such bracket structures, one at each end of the evaporator, as shown in Fig. 2.

It is within the invention to fashion the extruded stock in a succession of helical convolutions as shown. in Fig. 5. In some of the claims appended hereto the term convolutions is used, and this is intended to cover both forms shown in Figs. 1 to 7 inclusive, or the equivalent thereof. However, where the stock is helically wound, as shown in Fig. 5, the ends of the evaporator do not lie in a plane perpendicular to the axis, as illustrated; but this maybe taken care of by a suitable interfitting or filling structure. The helical windings shown in Fig. 5 are illustrated at $5.

A further modified form resides in the shape of the extruded stock. This is shown in Fig. 6. In this form the tubular portion is shown at 48, and it has oppositely extending flanges, one of which is shown at 41, and is beveled on its upper surface, and the other of which is shown at 48 beveled on its lower surface. When this extruded form is fashioned into successive convolutions the flanges overlap as illustrated at 46. Now this 'form of extruded stock may be employed in the form of the convolutions shown in Figs. 1 to 4, and it may be employed also in the true helical type of convolutions shown in .Fig. 5, and incidentally this form of overlap is illustrated in Fig. 5. In other words, it is not intended that the extruded form shown in Fig. 6 isonly for use with the type of convolutions shown in Fig. 5, since the extruded form shown in Fig. 4 is equally adapted to the Fig. 5 type of convolution.

In the modified form shown in Figs. 8 to 11 extruded stock is employed but it is not wound into convolutions, at least not in the sense of the convolutions of the foregoing forms. However, the stock is Wound into what is termed a coil, with successive portions-of the stock constituting successive coil sections. Accordingly, the term coil is used to describe a structure where the stock is fashioned in convolutions or successive runs extending back and forth or the like, such as is embodied in the modified form shown in Figs. 8 to 11. In these figures the inlet and outlet fixture, the auxiliary evaporator tube 26, and such parts have the same reference characters applied. The extruded stock in this form may have a shape as shown in Fig. having a tubular portion 50 with oppositely extending flanges 5|, but the flanges must be similar for reasons which will presently appear. As shown in Fig. 10 the flanges have a bead along their edge and the beads fit together so that a strip of sheet metal 52 may be fashioned thereover and more or less pressed or clamped into position. The beads may be grooved for the reception of an insert which may be in the form of a wire 53 for effecting alignment.

This form of extruded stock may be fashioned into successive coils or sections and the flanges are removed from the end portions as shown in Figs. 8 and 9, which end portions connect into the fittings 9 and it. The evaporator structure, as shown in Figs. 8 and 9, is formed as follows: Beginning at the left-hand end of Fig. 8 a length of the stock extends downwardly'as. at A, the stock then extends crosswise to form the bottom of the sharp freezing chamber as shown at A and then extends upwardly along the opposite side as shown at A". Some of the flange stock is removed and the tubular portion on is bent through substantially as indicated at 55. The stock then extends downwardly as at B across the bottom as at B and upwardly as at B". It will be noted that since the stock is fashioned through 180 that the meeting flanges on the coils are in effect the same flange. Therefore, the flange structure has to be arranged to fit an identical flange structure. At the top of the run B the flanges are removed and the stock bent through 180 as illustrated at 58, andthen the stock extends downwardly again in a second run A across the bottom and up the opposite side as at A". This structure continues until the evaporator is of sufficient size and its opposite end connects into the other fitting.

Preferably, this evaporator form is made as follows: The stock is fashioned back and forth with the runs A, A and A" straightened out in flat form; the runs 13, B and B" likewise in flat form, and so on until all of the runs or coils are fashioned. Then the whole flat form may be placed in a die and fashioned into U shape, with the runs A'and B constituting one side of the U, with the runs A" and B constituting the opposite sides and with A and B constituting the lower connecting bar of the U. This leaves the U form open at the top, but it may be closed by a suitable plate or partition similar to the partition i5, and the back end may be closed or partially closed by a plate 5? which may be corrugated as shown for strength purposes similar to the plate l5 as shown in Fig. 3. The holding strips 52 may be placed in position before or after the coils are fashioned into U shape.

Another form of flange structure is shown in Fig. 11. In this form the extruded metal has a central tubular part 68 with straight flanges 6i, and when the stock is fashioned'into convolutions or coils the same may be merely overlapped as illustrated, and the flanges may be secured together by spot welding or the like. Preferably, the overlap is such as to leave a substantially smooth effect on the exterior with the break between the flanges occurring on the inside of the evaporator.

This structure as described represents a complete evaporator unit, although before use it may be further ornamented and dressed up with suitable name plates at the front and a door may be used for closing the sharp freezing compartment. This, however, is beside the invention. It will be noted that an evaporator may be made by a simple manufacturing method; as the stock is wound into shape, the enclosed wallstructure for the sharp freezing compartment and the tube for the refrigerant are automatically completed.

This cuts down the number of operations over that structure where, for example, the walls 'for the compartment are of sheet metal and the tubes are separate therefrom and the Parts are fabricated and secured together in various ways. Moreover, it will be noted that cross sectional thickness of the stock, particularly at the tube formation which confines the refrigerant, is not unduly thick because the metal is densified by the extrusion process. The walls may be considerably thinner than that which would be-advisable the refrigerant entering the inlet fixture it first flows through the auxiliary tube 26 and thenthrough the main expansion tube i to the outlet fixture a. This arrangement gives a sort of double expansion action in that the refrigerant first expands in the tube 25 and again expands in the tube However, due to the smallness of the tube 2% it is believed that it is most always kept substantially filled with liquid refrigerant.

In the specification and claims the strip has been described by use of terms such as tube or tubular portion when referring to the portion which constitutes the conduit. Such terms are not to be construed in a limited fashion as covering a tubular arrangement which is more or less circular in cross section, but are to be construed broadly to cover a structure which serves as a conduit or which is of hollow cross sectional shape. Also, we have used the expression that the strip is of relatively great length, or expressions of this character. This is to be construed to mean that the strip has a length sumcient to form an entire evaporator, or an entire section or unit of an evaporator, or at least a plurality of runs or coils.

We claim:

1. An evaporator for a refrigerator comprising, an extruded metal strip of relatively great. length having a tubularportion and oppositely extending flanges thereon, said metal strip being fashioned into a plurality of coils, with the flanges of successive coils cooperating to form a solid wall.

2. An evaporator for a. refrigerator comprising,

an extruded metal strip of relatively great length an extruded metal strip of relatively great length being fashioned into a plurality of coils, the tubular portion constituting a continuous conduit for refrigerant and the flange means on successive coils cooperating to provide a substantially solid wall defining thespace within the coils, said space constituting a sharp freezing chamber, and

the area within the convolutions, the said secsaid flanges being united so as to be held in substantially continuous wall form. f

4. An evaporator for a refrigerator comprising, an extruded metal strip of relatively great length and which in cross section has a tubular portion and oppositely extending flanges, said strip being fashioned into a plurality of convolutions, with the flanges overlapping, the tubular portion constituting a continuous conduit for refrigerant and the overlapping flanges providing a substantially closed wall surrounding the space defined by the convolutions, with said space constituting a sharp freezing chamber, said flanges being weld united at spaced points.

5. An evaporator for a refrigerator comprising, an extruded metal strip of relatively great length which has a lengthwise extending tubular por= tion and oppositely directed flanges, said strip being fashioned into a plurality of convolutions with the flanges of successive convolutions cooperating and providing a wall substantially en-= closing the area within the convolutions, the flanges being removed from the end portions of the tubular form, and fittings secured to the ends bf the tubular form for the inlet and outlet of refrigerant.

6. An evaporator for a refrigerator comprising, an extruded metal strip of relatively great length, said strip in cross section having an intermediate tubular structure and oppositely extending flanges, said flanges being disposed in planes re= moved from each other a distance substantially equal to the thicmess of one flange, said strip be ing fashioned into a plurality of convolutions, with the flanges of successive convolutions overlapping and providing a substantially closed wall I for the space within the convolutions.

7. An evaporator for a refrigerator comprising, an extruded metal strip of relatively great length and having a cross sectional shape which presents a tube in its intermediate portion, and lat eral flange means extending therefrom, said strip being fashioned into a plurality of similar coils to provide a substantially hollow form of substantially uniform dimensions from one end to the other, the flange means of successive coils cooperating with each other to provide a wall of the said form substantially enclosing the space defined by the coils.

8. An evaporator for a refrigerator comprising, an extruded metal strip of relatively great length and which has a cross sectional shape which presents a tubular form in its intermediate portion, with'one side of the tube being flat, and a flange extending therefrom in the plane of the flat side 1 of the tube, and having another flange oppositely extending but spaced from said plane a distance substantially equal to the thickness of the first mentioned flange, said strip being fashioned into a plurality of similar convolutions, with the second mentioned flange of successive convolutions overlapping the first mentioned flange, whereby the flanges form a substantially unbroken wall defining a compartment within the convolutions.

9. An evaporator for a refrigerant comprising, an extruded metal strip of relatively great length, said strip having an intermediate tube portion 7 and oppositely extending flanges, the flanges being removed from sections at spaced locations along the length of the strip, the strip being fashioned into convolutions with each convolution having a major portion lying in a plane perpendicular to the axis of the convolution, with the flanges cooperating to substantially enclose tions of the tubular form being angularly disposed relative to the major portions and extending from one major portion to the next.

it; An evaporator for a refrigerator comprising, a plurality of convolutions offlanged tubing with the flanges cooperating to provide a wall defining a sharp freezing chamber,'each convolu tion having its major portion lying in a plane perpendicular to the axis of the convolution and a minor portion with the flanges removed from the tube, said portions where the flanges are removed being angularly disposed relative to the plane of the jor portion so as to extend from one major portion to the next.

ii. an evaporator for a refrigerator comprising, a plurality of convolutions or tinged tubing with the flanges cooperating to provide a wall defining a sharp freezing chambeneach convo1ution having its major portion lying in a plane perpendicular to the axis of the convolution and a minor portion with the nges removed from the tube, said portions where the flanges are removed heing aarly disposed relative to the plane of the major portion so as to extend from one major portion to the next, and a closure piece for completing the wall of the sharp freezing chamber at the location of said angularly disposed portions.

312. An evaporator for a refrigerator comprising, a flanged tube having oppositely disposed flanges lying in diflerent planes, said flanged tube being fashioned into a plurality of helical like convolutions with similar cross dimensions and. with the flanges cooperating to provide a wall substantially enclosing and forming a sharp freezing chamber 'within the convolutions.

the flange means removed and being bent through substantially 180.

14. An evaporator comprising, a length of extruded metal stockhaving an intermediate tubu-" lar portion with oppositely extending flanges, said length of metal being fashioned into 'a plurality of U "shaped sections, with the sections lined up in fore and aft relation and with the flanges cooperating to provide walls, the flanges being removed from portions of the stock between U shaped sections, and said portions being bent through substantially 180 to form a connecting loop between sections.

.15. An evaporator comprising, a single relatively long length of flanged tubing fashioned back and forth into successive runs of similar length, all of said runs being-substantially of U shape and said U shaped sections being aligned in fore and aft relation, said flanges on the successive runs serving to close the space between the tubular portions of the runs to provide a substantially closed wall. 1

16. An evaporator for refrigerators comprising, a length of extruded metal having an intermediate tubular portion and laterally extending flanges, said length of metal being fashioned into successive coils shaped to provide a form of hollow interior, with the flanges cooperating to provide walls defining the interior of the form, each flange having a beaded form at its edge and a holding strip fashioned over the beaded forms of adjacent edges.

17. An evaporator for refrigerators comprising,

a length of extruded metal having an intermediate tubular portion and oppositely extending flanges, said length of metal being fashioned into successive coils shaped to provide a form of hollow interior, with the flanges cooperating to provide walls defining the interior of the form, each flange having a beaded form at its edge and a holding strip fashioned over the beaded forms of adjacent edges, and alignment means positioned between the beaded edges to hold the edges in alignment.

18. An evaporator for a refrigerator comprising, a metal strip of relatively great length having a tubular portion and oppositely extending flanges thereon, said metal strip being fashioned into a plurality of coils, with the flanges of successive coils cooperating to form a solid wall.

19. An evaporator for a refrigerator comprising, a metal strip of relatively great length and which in cross section has a tubular portion and oppositely extending flanges, said strip being fashioned into a plurality of coils, the tubular portion constituting a continuous conduit for refrigerant and the flanges cooperating to provide a substantiallysolid wall defining a space within 1 the coils, said space constituting a sharp freezing chamber.

20. An evaporator for a refrigerator comprising, a metal strip of relatively great length and which in cross section has a tubular portion, and flange means extending laterally from the tubular portion, running lengthwise with the tubular portion, said strip being fashioned into a plurality.

of coils, the tubular portion constituting a continuous conduit for refrigerant, and the flange means on the coils cooperating to provide a substantially solid wall defining a space within the coils, said space constituting a sharp freezing chamber.

21. An evaporator for a refrigerator comprising an extruded metal strip of relatively great length having a tubular portion and flange means integral with the tubular portion and running lengthwise thereof, said metal strip being fashioned into a plurality of coils with the flange means of successive coils cooperating to form a substantially solid wall.

22. An evaporator for refrigerators comprising a relatively long length of metal having a tubular portion and flange means running lengthwise with the tubular portion, said length of metal being fashioned into successive coils with the said flange means on successive coils cooperating to provide a substantially solid wall structure, the said flange means having a bead-like edge and the bead-like edges of successive coils disposedin proximity, and holding means fashioned over the proximitive bead-like edges.

23. An evaporator for a refrigerator comprising, a metal strip of relatively great length having a tubular portion with lateral flange means thereon extending longitudinally of the strip, said metal strip being fashioned into a plurality ofcoils with the flange means extending crosswise of the space between successive tubular portions to form a wall, means on one end of the strip for connecting the tubular portion to a supply of refrigerant, and means on'the othervend of the strip for connecting the tubular portion to conducting means for carrying away evaporated refrigerant.

STANLEY H. MORSE.

WILLIAM W. HIGHAM.

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