US2143976A - Evaporator for use in refrigeration devices - Google Patents

Description

Jan. 17, 1939. L M. CROSLEY ET AL EVAPOEATOR FOR USE IN REFRIGERATION DEVICES Filed July 25, 1956 2 SheetsSheet l 4 n aw INVENTORS. A Zen/ls M Ceasu-Y. Faun/a Mozwsn ATTORNEYS.

Jan. 17, 1939. M. CROSLEY El AL 2,143,976

EVAPORATOR FOR USE IN REFRIGERATION DEVICES Filed July25, 1956 2 SheetsSheet 2 INVENTORS. LEW/.5 M C/PQSLEY, FoLA/vo h. Mon 5r ATTORNEY-S.

Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE 2,143,976 avsrons'roa nogg n IN REFRIGERATION CES Lewis M. Crosley and Roland H. Money, Cincinnati, Ohio, assignors to The Crosley Corporation, a corporation of Ohio Application July 23, 1986, Serial No. 92,172

8 Claims.

trays in the production of ice cubes for domestic use. In general, the type of our evaporator is one formed of sheets of metal united together and shaped so as to define refrigerant passages.

It is one of our objects to provide an evaporator in which the refrigerant instead of flowing from 10 one header to another through a. series of parallel passageways, in one direction, flows through a sinuous passageway throughout the evaporator in one direction, and then back again in the opposite direction. if It is an object of our invention to provide an evaporator structure which has sufilcient strength for domestic use, and which consists externally of a soft metal such as brass, which is relatively non-corrodible, and does not require extensive 30 surface treatment after it is formed up or prior thereto. To this end, in one modification we incorporate a steel sheet as a diaphragm or passageway defining element between two outer sheets of the brass, so arranging it, however, that the steel sheet is not exposed externally of the device, but terminates short of the welded together edges of the brass sheets.

In another modification of our invention we provide a soft metal diaphragm, such as a diaso phragm of copper, in a brazed construction hereinafter to be described.

We have illustrated a preferred form of our structure in the appended drawings, and will describe the same in detail, it being understood that the novelty inherent in the structure is set forth in the appended claims, to which reference is hereby made.

In the drawings: 7

Fig. l is a plan view of the evaporator prior 43 to bending. Fig. 2 is a section on the line 2-2 of Fig. 1. Fig. 3 is an edgewise elevation of the device shown in Fig. 1.

Fig. 4 is an elevation taken from the front of 47, the completed evaporator.

Fig. 5 is a side elevation of the said device as shown in Fig. 4.

Fig. 6 is a section on the line 5-6 of Fig. 5. Fig. 7 is a detail plan view taken of the por- '51) tion indicated at IF-i on Fig. 4;

' In forming the evaporator device, sheets of brass or other suitable soft, non-corrosive metal i and 2, are pressed or otherwise formed so as to present two semi-circular parts 3 and 4, which 55 when united together wi l orm a cylindrical (o1. sa -12s) header 5. The plate I is formed with an aperture for an entrance fitting 6 for refrigerant gases,- from which aperture asinuous corrugation 1 extends, this corrugation passing back and forth with a plurality of bends, then extending straight 5 as indicated at la, and then again formed into loops beginning at lb and terminating at la.

' Referring to Fig. l, the evaporator will be subsequently bent at right angles along dotted lines marked A, B and C, and the straight portions la of the corrugation in plate I traverse the section A to B. a The other plate 2 of soft metal or brass, has a sinuous passage which extends into the half portion of the header, and beginning at 8 describes a sinuous path of a series of loops termil5 nating at a point to, thence extending straight to the point so.

The steel sheet 8 need not be corrugated and is of a size such that its edge 9a falls short of the uncorrugated edges of the two soft metal plates when the steel plate is placed between the two soft metal plates, with the edges of the two soft metal plates coinciding entirely around the assembly. As so assembled, continuous welds It! i can be made extending in from the edges of the soft metal plates on both sides of the structure, where not interfered with by the loops of the corrugations. Also spot welds as at ll may be made uniting the two outer plates to the middle plate or diaphragm. Also the coinciding edges all the way around the structure are welded or brazed together, and if desired, a facing strip i2 may be mounted over what will be the front edge of the structure.

its so constructed the device is ready for bending into final form, which will result in the forming of a vertical wall II, the bottom wall [3, the side wall [4 and a top wall l5. Due to the arrangenient of the corrugations, the portion, id of the corrugations I, and the portion between 841 and 8b of the corrugation 8, will be at the back end of the finished structure, leaving flat tray supporting shelves at l6 and ii. A mounting bracket i8 may be secured to the one side of the device with a mounting plate IQ, for an electric light switch, the bulb being housed in the portion 20 of this bracket. In order to provide for tray lifting devices, consisting of a loop of wire 2| operated by handle 22, held in a plate 23, the loops of the corrugations in the two brass plates will be made shorter as indicated. In order to accommodate the mounting plate 23, the steel plate 9 is cut away as at 9b, thus permitting the mounting plates to be pressed in flush with the surface of the tray supporting shelves of the comways.

pleted device. The diaphragm or steel plate will have a hole 90 therein which permits the sinuous passageway 1 to communicate with the sinuous passageway 8 at the point 81). Otherwise the diaphragm serves to define, with the corrugations in the tray plates, semi-circular passage- As a result,- in the finished device, the refrigerant enters at 6, passes down the side E2, on the inside of the device, along the back of the shelf l6, up the side i4 and along the bottom of the shelf 51. The refrigerant then enters passageway 8, flows along the back of the shelf ii, thence through a sinuous path along the side M, the bottom i3, and up on the outside of the wall i2, from which it enters the head.

It will be apparent that this evaporator will be inexpensive to form, require no elaborate surface treatment, make it unnecessary to provide two headers, will provide for refrigerated walls as well as both shelves of the evaporator, and will be amply strong to withstand the necessary service.

A second modification of our invention has to do both with the use of lighter metal and with the avoidance of any possibility of buckling dur-- ing the bending step which may arise from the use of a. stiff or hard metal diaphragm member. Evaporators for domestic refrigerators have to he made to withstand considerable internal pressure especially when the machine is idle or during periods of shipment. The tensile strength of brass or other soft metals, that is, metals in fairly light gauges, is amply sumcient to sustain these pressures. Thus where a plate such as the plate I or 2 is embossed to form a passageway no dimiculty is experienced. Where, however, a flat portion of one plate lies opposite an embossed portion of another plate, as for example, between the dotted lines A and B in Fig. 1, and where the flat portion of the plate is subjected to internal pressure, there may be a slight distortion of the plate between the lines of welding, producing a slightly irregular surface and an unsightly appearance. In the modification of our invention which we are now describing we make use of the diaphragm as a means for reenforcing a flat or unembossed portion of a plate lying threagainst. In an exemplary manufacture of this type of evaporator we may employ for example, as the plates l and 2, plates of brass of .025 inch in thickness, and we may employ as the diaphragm the plate indicated in the figures at 9, that is a plate of copper, say of .020 inch in thickness. It willbe understood that these dimensions are exemplary only and are not limiting. The plates (or at least the diaphragm plate) having been suitably coated with a flux after cleaning, are assembled as has been indicated, and then the plates are brazed together throughout their contacting surfaces, preferably by the now well-known hydrogen brazing method. The plates in their fiat portions are thus integrally joined. In the embossed portions the .025 brass will have suflicient tensile strength to give an adequate margin of safety. Over flat portions at least one plate will be joined to the diaphragm plate. giving an effective metal thickness or gauge of .045 at least, this being amply sufiicient to withstand any tendency for the plates to distort under the internal pressures to which the evapora or may be subjected.

It will be understood that in forming this type 01' evaporator it will be necessary to choose both for the outer plates l and 2 and for the diaphragm member 9, metals which are capable of being brazed together. The use of a softer metal in the diaphragm member makes the bending up of the evaporator structure into the forms shown in Figs. 4 and 6 somewhat easier in that there is less tendency toward buckling.

In the manufacture of either of the modifications of the evaporator described herein, it will be desirable to roughen portions at least of the surfaces oi the diaphragm member or inside portions of the surfaces of the other plates so as to promote boiling of the liquefied refrigerant. It will also be understood to be within the scope of our invention, where embossed passageways cross the lines along which the evaporator is to be joined, to make the embossed passageways at such points larger or different in cross section so as to compensate for any swaging or flattening of the passageways which might occur during bending.

Having thus described our invention, what we claim as new and desire to secure by Letters Patcut is:

1. An evaporator structure comprising a pair of plates made of soft relatively non-oxidizable metal, and an interposed diaphragm formed of iron or steel, each plate having corrugations therein to form in cooperation with the interposed diaphragm a refrigerant passageway, said diaphragm terminating short of the edges of said plates, the edgesof the plates being welded together, said diaphragm being provided with an opening connecting the corresponding ends of said passageways.

2. An evaporator structure comprising a pair of plates made of soft relatively non oxidizable metal, and an interposed diaphragm formed of iron or steel, each plate having corrugations therein to form in cooperation with the interposed diaphragm a refrigerant passageway, said diaphragm terminating short of the edges of said plates, the edges of the plates being welded together, said diaphragm being provided with an opening connecting the corresponding ends of said passageways, said plates at one end being formed into a header for the return flow passageway.

3. In an evaporator assembly, a pair of plates welded together at the edges and spread at one end of the assembly to form a header, a diaphragm plate secured between the two plates, a sinuous bead formed in each outer plate to form in cooperation with the diaphragm plate a passageway for refrigerant, said latter plate arranged to close the passageways from each other, said diaphragm being provided with an opening at said end to provide a port between said passageways.

4. In an evaporator assembly, a pair of plates welded together at the edges and spread at one end of the assembly to form a header, 2. diaphragm plate secured between the two plates, a sinuous bead formed in each outer plate to form in cooperation with the diaphragm plate a passageway for refrigerant, said latter plate arranged to close the passageways from each other, said diaphragm being provided with an opening at said end to provide a port between said passageways, said plates and diaphragm bent to form a rectangular open end structure, thus'presenting a lower and an upper ice tray shelf.

5. In an evaporator assembly, a pair of plates welded together at the edges and spread at one end of the assembly to form a header, a diaphragm plate secured between the two plates, 2. sinuous bead formed in each outer plate to form in cooperation with the diaphragm plate a passageway for refrigerant, said latter plate ar aicao'zo ranged to close the passageways from each other, said diaphragm being provided with an opening at said end to provide a port between said passageways; said plates and diaphragm bent to form a rectangular open end structure, presenting a lower and an upper ice tray shelf portion, the sinuous bead in each shelf portion being so arranged therein so that said shelf portion presents a substantially fiat surface for supporting an ice tray,

plates and a diaphragm plate therebetween, said outer plates being embossed'toform passageways completed by said diaphragm member, certain embossed portions in one plate lying opposite flat portions in the other plate, and said diaphragm plate being joined to said flat portions of said other plate whereby to stiffen said fiat portions.

'7. In an evaporator, a pair of outer plates and 6. In a refrigerator evaporator, a pair of outer a diaphragm plate therebetween, said outer plates being welded together about the edges thereof and being embossed to form passageways completed by said diaphragm plate, and entrance and exit means for refrigerant, at least one plate surface located interiorly of said evaporator being roughened to promote the boiling of liquid refrigerant therein said diaphragm plate terminat ing short of the edge welded portions of said v outer plates.

8. An evaporator structure comprising a pair of plates and a diaphragm interposed.- between the same, said plates having corrugations therein to form passageways in cooperation with the diaphragm, said diaphragm terminating short of the edges or said plates, the edges of the plates being welded together, and said diaphragm roughened to promote boiling of the refrigerant.

LEWIS M. CROSLEY. ROLAND H. MONEY.

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