US 2154216 A
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April 11, 1939. M. A SAVAGE COOLING PAD Filed June 24. 1936 e, e5 wv n 0% r mbv@ GA/LW Vn A www 4 r s MQWH U4 9 Ilf Patented Apr. 11, 1939 UNITED STATES COOLING PAD Marion A. Savage, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application June 24, 193e, serial No. 86,966
My invention relates to cooling pads which are primarily adapted for insertion between bundles of laminations in dynamo-electric machine core structures for removing heat therefrom. These cooling pads have substantially parallel flat face portions which make contact with the bundles of laminations and transfer the heat from the laminations to a cooling fluid circulated through the pad.
m Itis an object of my invention to provide a pad of improved construction.
It is a further object of my invention to provide a pad in which the parts thereof are formed of metal sheets and strips integrally attached to one another to form a unitary structure.
` embodying the structural features thereof; Figs.
2 `to 6 inclusive, are views illustrating the procedure by means of which this pad is fabricated; Fig. 7 is a pla'n view of the interior arrangement i of the partition and reinforcing strips attached to the inner surface of one of the sheets forming the pad; and Fig. 8 is a cross section of the body portion of the pad shown in Fig. 1. Fig. 2 illustrates the two flat sheets from which the pad is fabricated by being simultaneously formed as shown in Fig. 3, and then separated for -removal of the edge portion of one of the sheets as shown in Fig. 4. Figs. 5 and `6 illustrate the attachment -to the outer and inner surfaces of these sheets of cooling fins and partition and reinforcing strips. The hollow cooling pad shown in the drawing has two substantially parallel faces formed by the body portions of two sheets III and II, the edges of which have been turned up to form flanges I2 and I3. These fianges are turned toward one another to space apart the body portions of the sheets and are integrally attached to one another throughout their lengths to form the edge walls of the pad, as well as the side walls of two flared nipples I4 and I5 formed by projections arranged one within the other and extending fromthe edge of the pad. y The configuration of the pad and the location of the nipples will depend on the use to which the pad is put. In the construction illustrated, the lower portion of the pad is divided by a slot I6, which forms finger-like portions I l and I8 opposite the side from which the nipples project. This slot I6 is made to accommodate windings located in the slots of laminations forming the core structure of a dynamo-electric machine and between 5 which laminations the pad is located.
Metal strips I 9 of substantially the same width as the width of the flanges of the sheets Ill and II are attached to the inner surfaces voi' the body portions of the sheets I0 and II. As shown in m Fig. 7, these strips are laterally spaced from one another with the outer strips I9 spaced from the ends of the portions I'I and I8, and with the intermediate strip I9 spaced from the wall between the nipples I4 and I5 to form a sinuous 15 passageway which extends between the openings in the pad provided by the nipples. The ends I9a of these stripsare slightly spaced from the adjacent flanges of the sheet Il to slidably receive the fianges of the sheet I0. In the resulting 20 pad construction the strips I9 are thus spaced from one another and alternately from opposite flanged portions of the sheets IIJ and Il to form the sinuous passageway referred to. Additional strips 20, having the same width as the strips. I9, 25 are also attached to the inner surfaces of the body portions of the sheets I0 and II and extend along the central portion of the passageway formed by the strips I9. 'I'he ends of these additional strips are spaced from one vanother at 30 points opposite the central portions of the strips I9 to provide for a pressure equalization of the cooling-fluid flowing on opposite sides of these strips through the passageway defined by strips I9. Strips I9 and 20 serve to reinforce the pad 35 against the compressive force exerted on its face portions in the assembled core structure of a dynamo-electric machine. These strips also act as baiiles by means of which the cooling fluid is directed in a predetermined path which brings it 40 into intimate contact with the total surface portion of the cooling pad.
For some applications one of the external faces of the pad may be provided with cooling fins 2i attached thereto in any desired arrangement such 45 as illustrated in Fig. 1.
The structure of the pad will be further described in connection with the procedure by means of which it is fabricated. This procedure forms the subject matter of my above referred to 50 divisional application and is as follows:
Two metallic sheets I0 and I I are placed one upon the other in a press by means of which their edge portions I2 and I9 are simultaneously turned up to form pans which closely fit one with- 56 sheet il. I 4in Fig. 4, is removed from its turned up edge portion l2, to facilitate the assembly of these in the other, as shown in Fig. 3. The excess v metal 22 at the rim of these pans is simultaneously removed from the turned up portions of the sheets to form flanges of substantially uniform width. The inner pan formed of sheet il is then separated from the outer pan formed by Additional metal, above the line ifa sheets with their flanges turned toward and overlapping one another to form the hollow portion of the pad.
The sheets are then preferably cleaned by immersing them in hot water. a cleaning solution, or a pickling bath, to remove o. and dirt therefrom, and the surfaces of the sheets where they are to be attached to one another and to the c strips II, 10 and 2i are preferably roughened by suitable means such as steel grit directed thereon through the agency of an air blast. Strips l! and 20 are then attached by welding them at intervals, as indicated at IIb and 20h, to the inner surface of the body portion of sheet Il, as
shown in Fig. 6. Strips 2| are then attached,
preferably by welding, to the outer surface of the body portion of the sheet III, as shown in Fig. 5. The turned up edges of the sheets III and Il and their surface areas, as well as vthe surface areas of the strips I9, 20 and 2|, are then coated with a brazing material such as copper. which may be applied thereto as a molten metal spray. The parts are then assembled as shown in Fig. 8 with the edge of .sheet Il turned over the body portion of sheet I0 and the projections constituting the nipples i4 and i5 formed around one another thus bring the edge portions of the sheets in close contact with one another. The assembly is then placed in a brazing furnace with the assembly resting on the outside surface of the body portion of the sheet. Il. Any suitable arrangement for applying a pressure to the assembly may be placed in engagement with the ilns 2 i The brazing operation is preferably performed in a hydrogen furnace to effect that species of brazing known as hydrogen brazing. In the presence of an atmosphere of hydrogen' the copper brazing material readily iiows into the crevices of the assembled parts and unites them one to the other in a manner closely approaching the condition of a welded union. The pad after the brazing operation is an integral structure in which all the parts are ilrmly attached one to another through their contacting areas by the hydrogen brazing operation.
The nipples Il and I5 are flared to facilitate the attachment therein of metallic conduits, the
A ends of which can be soldered to the nipples by puddling the solder in the annular space provided by their flared portions. I prefer to perform soldering operation by using a silver solder. melted by the flame of a welding torch in the presence of a fluxing material.
The metal of the pad structure may be of any suitable kind. but I prefer to use for the sheets- Il and Ii and the strips Il and 2l, a copper nickel alloy known to the trade as Manel metal. I
usethismaterial becauseofitsresista'ncetocorrosion as well as its high electrical resistance which prevents undue heating due to eddy current lossesinthepadwhenusedaspart ofthe core structure of- 'a dynamo-electric machine. Thenns 2| may be made of a low carbon steel dr any other suitable material. These fins are provided to space the pad from an adjacent bundle of laminations and form eways for the circulation of cooling gas between the pad and the bundle of laminations. These tins 2| may or may not form part of the pad structure. When used they also serve to conduct heat from the bundle of laminations placed in contact therewith to the pad and to the cooling fluid circulated in the pad.
It is, of course. apparent that variations may be made in the structure of the pad, as well as in the procedure by means of which the pad is fabricated without departing from my invention. For example, the parts may be attached to one another by welding. Furthermore, the flanged edge portions of the sheets need not necessarily overlap one another, and may be provided with rims for facilitating certain welding operations. It is also apparent that the strips i9, 2li and 2| are not necessarily attached throughout their lengths to the sheets Il and il, although such construction strengthens the pad and facilitates the transfer of heat through the strips 2| to the body portion of the plate to which they are attached.
What I claim as new and desire to secure by Letters Patent of the United States, is:
l. A at hollow pad the faces of which are the body portions of two parallel sheets having flanged edge portions turned toward one another and integrally attached to one another throughout their lengths to form the edge walls of said pad, said flanged edge portions having cooperating projections arranged one withinthe other to form a nipple communicating with the interior of said pad.
2. A flat hollow pad having strips therein attached to the inner surfaces of the faces of said pad and spaced from one another nd alternately from opposite edge walls of said pad to form a sinuous passageway of non-uniformly varying cross-sectional area which occupies substantially all of the hollow portion of said pad and having attached to the inner surfaces of the faces of said pad and extending along each portion of Said passageway between said first-mentioned strips and between said first-mentioned strips and the edges of said pad adjacent thereto a plurality of aligned strips, the adjacent ends of which are spaced from one another at points opposite the central portions of said first-mentioned strips and adjacent to points of material variation in the cross-sectional area of said sinuous passageway.
MARION A. SAVAGE.