US999870A - Electrical apparatus. - Google Patents

Description

K. C. RANDALL. ELECTRIGAL APPARATUS.

APPLICATION FILED JULY 28, 1909.

999,870. Patented Aug. 8,1911.

4 NVENTOR m1: 6 flwbw ATTORNEY UNITED STATES PATENT OFFICE.

KARL C. RANDALL, OF EDGEWOOD PARK, PENNSYLVANIA ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

Appucationfiled July 28, 1308.

Specification of Letters Patent.

ELECTRICAL A PPARA'IUS.

Patented Aug. 8, 1911.-

Serial No. 509,984.

oi lldn'ewood Park. in the count of Alle- ,g'hen and State of Pennsylvania, have iiiveuted a new and useful Improvement 111 l .lectrical Apparatus, of which the following is a specification.

My invention relates to electrical apparatusyaml it has special reference to t'ansformers and other devices which are provided with .inclosimgtanks or casings wholly or partially tilledwith air or other fluids.

The object o't my invention is to provide means for preventing a condensation of u'loisture within the casings of devices of the class above indicated that shall be Slll'lPlQ and lllOXPQllSlYQ in construction and etlicient in operation. I

\Vhcn transformers and other electrical devices are inclosed in tanks and are located in the open air, changes in the outside temperature, relative to the temperature within, will frequently cause a so called breathing action," which term is ordinarily applied to such a transfer of air from outside to inside as causes a condensation of moisture on the traniormcr coils and on the insideof the lven though the air which is withcasing. in the transtormcr casing is ordinarily pert ectly d ry,'the increase of temperature within causes air to be forced out of the casing and, as the transformer assun'ics alowcr temperature, outside air chargedwith moisture will enter the 'asin As this process is repeated, a material amount of moisture will accumulate and endanger the insulation of the apparatus, particularly if it is used in high potential service.

According to my present invention, I provide mcansjtor holding the-air within the transtorn'icr casing at a pressure which is slightly greater than that of the outside atmosphere in order that any flow of air may be outward instead of inward. In order to compensate For any small leak in the transformer casing, a constant supply of air is n'iaintained.

The single figure of the accompanying drawing is a diagrammatic plan viewo'f a plurality of transformers, the tanks of which are connected to the pressure-producing apparatus of my invention.

Referring to the drawings, transformers or other electrical apparatus are disposed within the casings 1, 2, and 3 which may be filled with air or partially filled with liquid insulation, a slight pressure being main-- taincd within the casing by means of a pump or blower i. This pump produces a relatively high pressure within. a storage tank or reservoir 5 which is supplied from. the outside atmosphere through a chambr'li containing hygroscopic material, the pressure being cut down by a reducing valve 7 'before it enters the transformer casings.

The storage reservoir maybe omitted but it will ordinarily be founddesirablc, in,

order to avoid the necessity of operating the pump continuously. For example, if the transformer tanks are practically free from leaks, an auxiliary reservoir may be filled with dry air, or some other suitable fluid, by operating a pump for a relatively short time, and several days may then elapse before it; is necessary to again operate the pump.

By maintaining a relatively low pressure in a large storage tank, the reducing valve may be omitted.

A relatively small pump will serve to sup-' ply the necc any pressure to a large number of transformershaving sealed tanks, since the pressure of a few ounces will usually be found sutiicient to prevent the breathing action.

I do not wish to be limited to the use-of dry air for preventing i'noisture from gathering on the transformer windings, since any suitable insulating dchydrated fluid or combination of fluids may be employed.

I. claim as my invention:

l. The combination with electrical apparatus and an inclosing'casing therefor, of means for continuously supplying dehy drated fluid to the casing to maintain an outward pressure slightly greater than that of the atmosphere.

"2. The combination with electric apparatus and an inclosing casing therefor, of a relatively high-measure storage reservoir, a pump for supplying dry air thereto, and means for supplying dry air from the storage reservoir to the casing at a reduced pres-' sure.

3. The combination with an electric trans: former and an inclosing casing therefor,- of a relatively high-pressure storage reservoir, a chamber containing hygroscopic material, a reducing valve between the inclosing casilrg and the storage res rvoir, and means for forcing the air through the hygroscopic materlal into the storage reservoir from which it is discharged at relatively lowl a pressure into the casin 4. The combination with an electric transhygroscopic material, and :1V pump for forc- 10 mg lnsulating fluld through the chamber "containing the hygroscopic material into ;the reservoir, dry air from the reservoir being continuously supplied to the casing.

In testimony whereof, I have hereunto subscribed my name this 21st, (la of July, 15

lVitnesses Hum-2N llux'rox,

B. 13. I'IINES.

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