US2249445A - Transformer casing - Google Patents

Description

July 15, 1941. M, UNGER` 2,249,445

' TRANSFORMER CASING Filed Sept. 25, 1939 Patented July 15, 1941 TRANSFORMER CASIN G Magnus Unger, Pittsfield, Mass., assigner to General Electric Company, a corporation of New York Application September 2,3, 1939, Serial No. 296,255

1 Claim.

My invention relates to transformer casings, l

and more particularly to transformer casings of Very large size. After a transformer has been manufactured, it is desirable that it be shipped to its final location in a sealed casing, which will protect it from outside air and moisture. The simplest way to ship the transformer is to ship it in its own permanent casing, but the casing for a large transformer may be so tall as to exceed the limitations due to railroad clearances. This difficulty has been overcome in many cases by providing a joint in the wall of the casing near the top of the transformer, the transformer then being shipped in the lower section of its casing and the upper section of the casing being removed andv shipped separately. In order that the transformer may be properly tested at the factory before shipment, it is desirable that the complete transformer with its casing be assembled, the upper section of the casing being removed during shipment and the transformer and casing being again permanently assembled after reaching the final location. During the short time required for testing the transformer, the joint in the casing wall need not be perfectly tight and may, therefore, be of a more or less temporary character, but when the casing is finally assembled in its final location, the joint should be permanently leak proof, so that no insulating liquid inside the easing can escape and no moisture or air can find its way into the casing from outside.

The general object of the invention is to provide an improved construction of joint between the upper and lower sections of a transformer casing.

The invention and its advantages will be explained in the following description taken in connection with the accompanying drawing in which Fig. 1 shows a transformer casing with a joint constructed in accordance with the invention; Fig. 2 is a sectional View of a portion of the side wall of the casing; Fig. 3 is a sectional view of one side of the upper section of the casing; Fig. 4 is a sectional view of a fragment of the lower section of the casing; Fig. 5 is a sectional view of a portion of the side wall of the casing after final and permanent assembly; Fig. 6 is an enlarged sectional View of the joint between the upper and lower sections of the casing, and Fig. 7 is a sectional view indicating a modied form of joint.

Like reference characters indicate similar parts in the different figures of the drawing.

The transformer casing I0 shown in Fig. 1 includes an upper section II and a lower section I2 secured together by a joint I3. This joint I3 includes an angle strip I4 welded to the lower edge portion of the upper section II of the casing and an angle strip I5 welded to the upper edge portion of the lower section of the casing. The angle strip I4 has one flange I5 arranged vertically and with its outer face secured to the lower edge portion of the casing section I I by a pair of welds I1, the other flange I8 of this angle strip I4 extending horizontally outward from the upper edge of the flange I6 and from the casing wall. The other angle strip I5 has one ilange I9 arranged vertically with its outer face secured to the upper edge portion of the lower casing section I2 by a pair of welds 20 and a horizontal flange 2l extending horizontally outward from the upper edge of the flange I9 and from the casing wall. After the welds IT and 20 have been completed, they may be tested for tightness by gas forced under high pressure through test openings, which are sealed after the tests are completed by threaded plugs 22.

In order that the transformer may be tested before shipment from the factory, the two sections II and I2 of its casing are assembled as shown in Fig. 2 and Fig. 6 with the lower edge of the flange I6 of the upper angle strip I4 resting upon the upper surface of the lower angle strip I5 near the base of its horizontal flange 2I. A gasket 23 is provided between the two angle strips to seal the joint between them and prevent any appreciable leakage of insulating liquid in which the transformer may be immersed inside the casing. The two angle strips I4 and I5 and consequently the two sections II and I2 of the casing are secured together by bolts 24 passing through the horizontal flanges I8 and 2| of the two angle strips. These two flanges I8 and 2| are spaced apart near their base portions by the flange I 6. Spacers 25 in the form of tubes surrounding the bolts 24 are further provided in the space between the outer portions of the flanges I8 and 2|, so as to prevent undue strain on the welds` I'I and 29. The gasket 23 may be a simple cork or rubber strip compressed into a groove in the lower edge of the flange I6, its only function |being to seal the joint temporariljr and to prevent any appreciable leakage during the brief period while the transformer is undergoing test. Because of th temporary character of this sealed joint during the test, it is, of course, not necessary that the upper surface of the angle strip I5 covered by the gasket be very carefully finished.

After the transformer has been tested at the factory, it may be enclosed for shipment to its final location in the lower section I2 of its casing with the upper section I I of the casing removed for separate shipment. Before the upper section I I of the casing is removed, the insulating liquid within the casing is drawn 01T to a level below the top of the lower casing section I2. Ihe bolts 24 are then loosened and the upper casing section II removed. Any accessories, such as the bushings 25, carried by the cover 2'I of the casing, are, of course, removed and shippedseparately. This permanent cover 2'! of the casing may be used to close the top of the lower section I2 during shipment of the transformer or a special shipping cover may, of course, be used if desired. If the permanent cover 21 is used during shipment, then any openings for the bushings 26 and for any other accessories should, of course, be sealed.

After the transformer reaches its final location in the lower casing section I2, the cover 2`I may be removedY the two sections II and I2 of the casing reassembled, and the cover 2l replaced in the top of the upper casing section. In thus reassembling the casing sections II and I2, the gasket 23 between the two angle strips I4 and I5 is preferably an asbestos gasket. The two angle strips I4 and I5 are now secured and sealed together by a weld 28 between the outer face of the flange I5 and the upper face of the flange 2 I. During this welding operation, the gasket 23 will prevent any fused metal from entering the casing through the joint between the angle strips I4 and I5, and it will also permit the weld 28 to be tested for tightness by gas forced under pressure through a test opening leading to the joint between the gasket and the Weld as indicated clearly in Fig. 6. The bolts 24 passing through the flanges I3 and 2i hold the angle strips I4 and I5 tightly together while the weld 28 is being formed and help to prevent subsequent strain on the welded joint. After the two sections II and IZ of the casing have been secured permanently together in their nal location, the casing may be lled with insulating liquid and the transformer made ready for service.

The invention provides a joint for a transformer casing which does not require any work Whatever inside the casing, so that all assembly and disassembly may be performed without removing the transformer from the lower section of the casing.

The modified form of joint indicated in Fig. 7 may be desirable Where the vertical flange I5 of the angle strip I4 is so thin that a groove for the gasket 23 cannot be conveniently formed in its lower edge. In such case, a narrow strip of metal 29 may be welded along the inner surface of the ilange I6 and the gasket 23 located in a groove just inside this strip 29 as indicated in Fig. 7.

The invention has been explained by describing and illustrating a particular construction of joint for a transformer casing and a modification thereof, but it will be apparent that changes may be made without departing from the spirit of the invention and the scope of the appended claim.

What I claim as new and desire to secure by Letters Patent of the United States is:

A separable transformer casing comprising a lower section containing a transformer and an upper section provided with vertically extending bushings, angle strips welded along the adjacent edge portions of said sections, the angle strip of said lower section having a vertical flange welded to said lower section and a horizontal flange extending outwardly above the upper edge thereof presenting a plane surface for clamping a shipping cover thereto, the angle strip of the upper section having a vertical ilange welded thereto with the lower edge thereof extending beyond the lower edge of said upper section and a horizontal flange extending outwardly from the upper edge of the vertical flange, the lower edge of said vertical flange of said upper section being adapted to be welded to the upper surface of said angle strip of said lower section.

LIAGNUS UNGER.

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