US1793820A - Transformer or the like - Google Patents

Description

Feb 24, 1931.

L. Z1. NICHOLS TRANSFORMER OR THE LIKE Filsd Nov.

19, 1924! 2 Sheets-Sheet Feb. 24, 1931. L. c. NlcHo s 1,793,820

TRANSFORMER OR THE LIKE Filed Nov.

9, 1924 2 Sheets-Sheet 2 ported by br velop Within i 'ntentod Felt 234, 1933 UNITED STATES LOUIE! MIANU.

.W'IQHOLS, DE 'WAUWATOSA,

PATENT OFFICE rro snms cnarmans coaronarrou or TRANSFORMER OR THE LIKE Application filed November 19, 1924. Serial No. 750,782.

This invention relates to enclosed electrical apparatus adapted to be filled with oil or other insulating i'illlCi. The term oil is used iercinaiter, for sake of brevity, to connote on y suitahle insulating fluid. One of its uses is in connection with oilfilled transisers and it will he more particularly dcscribed in "that relation.

Giving to the fact that the oil in transformiltcrnately heated and cooled and there lore expand" and contracts, provision most ake care of this expansion and tion where the casino oi the transis completely oil-iilicc.. I t is also do: e to keen the surface the oil exposed atnios 1:5 as cool as possible to minimize c the oil. It is further desirable revent the entrance of moisture into the isformer casing. Occasionally explo sions or hi pressures approaching an explosive or destructive nature are developed ithin the transformer casing and it is desire. le to relieve these with maximum rapidity. is one of the ohjects of the invention to provide means whereby chess desirable featurns be attained with minimum of parts and also in an eilicient manner.

in the past expansion chambers connected by means 05 a small pipe to the top of a complctely oil filled transformer easing have provided hut these pipes have not been designed nor adapted to take care of explosive pressures Within the casing, and, also, in practice the It is another :t of this invention to provide a construe. on in which explosive or high pressures may be readiiy taken care of and the before mentioned brackets dispensed with.

Inasmuch as transformers are often located out of doors, and in certain places are therefore exposed to low temperatures, it may occur, especially if the transformer is out of service for a time, or the load is small, that the oil in the expansion chamber or the pi e connecting it to the transformer gets so stantially solid and when the transformer is again put in service high pressures may de- I casing as the soiidified oil is iansion chambers were sup- 'vater which may collect difiicult to move through a small opening. It is accordingly an object of the invention to provide means whereby these undesirable effacts may be avoided. It is a more specific object to provide means whereby even though the load on a transformer is small the passage between the transformer casing and the expansion chamber will be kept open, or if the oil (loos solidify, high pressures may be relieved and their destructive effects avoided. Other objects will appear hereinafter as the description of the invention proceeds.

The novel features of the invention will appear from this specification and the accompanying drawings forming a part thereof and disclosing several embodiments of said. invention and all these novel features are intended to be pointed out in the claims.

In the drawings, in which corresponding parts have been given the same reference character:

Fig. 1 is a fragmentary side elevation of a transformer in which the invention has been embodied, parts being in section. i

Fig. 2 is a similar view of a modificaton.

F ig. 3 is a fragmentary rear elevation of the transformer of Fig. 1.

Figs. 4 and 5 are fragmentary side eievations of modifications, parts being in section.

Referring to Fig. 1, a transformer casing 1 adapted to contain the core. windings and other transformer elements proper, is here shown as provided with low tension bushi ngs 2 and one or more high tension bushings 3. An expansion tank or chamber (usually of cylindrical form but not necessarily), is in communication with the top of tank 1 through a large conduit. This conduit is here shown as comprising a pipe section 5, usually Welded to the lid of the tan}; 1, and a pipe section 6 usually welded to the expose sion tank 4. The pipe sections 5, 6 may be fastened together by bolts not shown, pass ing through a pair of flanges 7, 8 associated with pipe sections 5, 6 respectively. In Fig. 1 the pipe section 6 is shown as extending through and into the expansion tank 4, the lower edge of the end of pipe (1 being preferably above the bottom of tank 4 so that any in said tank will not be drawn into the transformer tank. The upper edge of the end of pipe 6 within chamber 4 is here shown as below the cold level of the oil in the chamber 4. A pipe 9 communicating with chamber 4 and usually welded thereto is disposed so as to be in line with the pipe 6. The pipe 9 is, provided with aclosure or valve 10 which may be swingable about a pivot 11 mounted on a suitable bracket in turn mounted on the pipe 9. The valve 10 may be held closed by means of a breakable bolt 12. Any other suitable form of openable closure may be substituted for the valve 10.

In order to prevent the circulation of hot oil from the transformer tank through the pipes 5, 6 directly to the level of oil in the expansion chamber 4, the end of the pipe 6 within chamber 4 is provided with a suitable valve 13 which may be pivoted at a point 14:. The valve 13 is itself here shown as provided with an opening 15 which may be held closed by means of a valve 16 pivoted to the valve 13 at the point 17. A weight 18 is here shown as associated with the valve 16 and so disposed with respect to the pivot 17 that the valve 16 is normally held closed by the action of gravity. Other suitable means may clearly be substituted. The chamber 4 is provided with a vent pipe 19 of any suitable form thereby placing the air above the oil in chamber 4 in communication with the atmosphere. The bottom of chamber 4 is provided with a drain cock 20 through which water or sediment may be drained chamber.

The operation of the apparatus shown in Fig. 1 is as follows. As the oil in transformer 1 heats up it gradually expands and some of this oil is expanded out through pipes 5, 6 thereby lifting the valve 13 and permitting this oil to flow into expansion chamber 4.

' Air is of course then expelled through pipe 19. When the oil in tank 1 cools it contracts thereby opening valve 16 and drawing oil from the expansion chamber 4. When no expansion or contraction of the oil in tank 1 is taking place communication between expansion chamber 4 and tank 1 is cut off by the valves 13, 16, and as hereinbefore stated circulation of hot oil from tank 1 to the surface of the oil in chamber 4 is prevented. This circulation of oil, however, keeps the oil below the valve 13 in a fluid condition so that the oil at the point of communication between chamber 4 and the end of pipe 6 within said chamber will not solidify in cold weather. If an explosion occurs within tank 1 the pipes 5, 6 constitute a straight line exit from tank 1 and inasmuch as pipe 9 is in line with pipe 6 any oil or gas shot through pipe 6 will readily leave by way of pipe 9 after the valve 10, due to the high pressures, has opened.

Referring now to Fig. 2, a pipe 21, corresponding in some respects to pipe 6 of Fig. 1, is here shown as extending from flange 8 from the bottom of said through the expansion chamber 4 from one side to the other, the joints between pipe 21 and chamber 4 being of course made oiltight. The pipe 21 is provided with an opening 22 within the chamber i and above the bottom thereof. The opening 22 serves as the only means of communication between the oil in chamber 4: and that in pipe 21. The upper end of pipe 21 is provided with an openable closure as described in connection with Fig. 1. It will be noted that as in Fig. 1, a. straight line discharge path is provided for relieving explosive pressures from tank 1 through pipes 5 and 21 through the end of that pipe when valve 10 opens. Inasmuch as the air in pipe 21 above the oil level is not in communication with the atmosphere there is no so called breathing action as to this air when the oil in tank 1 expands and contracts. It is therefore evident that though the oil in contact with the air in pipe 21 may be warm, no appreciable sludging can take place for the reason that this air is not renewed as the transformer breathes. If desired the surface of the oil in pipe 21 may be kept cooler by providing a butterfly valve comprising substantially semi-eircular disks 23, 24 suitably pivoted at the point 25. Suit able stops 26 maybe provided to limit the motion of the valve members 23, 24 in a direction toward the transformer tank. The butterfly valves 23, 2a need not necessarily be a close lit within pipe 21 inasmuch as its principal purpose, if employed, is to prevent the circulation of oil within pipe 21 clear up to the oil level in that pipe. It is however desirable to permit circulation of some warm oil in pipe 21 from tank 1 approximately up t the opening 22 so that the oil at that point will be kept in a liquid state, for reasons hereinbcforc noted.

Referring now to Fig. 4 communication is established between chamber l and the transformer tank 1 by means of a pipe 27 corresponding in some respects to the pipe 21 of Fig. 2. The pipe 27 is provided with an opening 22 located similarly to the opening of the same reference numeral in Fig. 2. The pipe 27 does not however extend clear through the expansion chamber but ends a predetermined distance from the upper side thereof. A pipe 9 provided with an openable closure 10 as described in connection with Fig. 1 is provided in communication with chamber 1 and disposed in line with the pipe 27 so that any explosive discharge from pipe 27 may be quickly relieved. In case a transformer constructed as shown in Fig. 4 should be left for a considerable period without any current passing therethrough and the weather should be-cold enough to solidify the oil in pipe 27 and current should then be sent through the transformer thereby heating up the oil in tank 1, the slug of oil in pipe 27 would be ex pelled from the end of that pipe within the chamber 4 and pass into said chamber, displacing the air t erein and expelling it from pipe 19. It is therefore clear that in this modification under these particular condi-. tions the closure 10 would not be opened. However, if explosive pressures occurred within tank 1 the air in chamber 4 would not pass out of pipe 19 sufficiently rapidly and valve 10 would be opened thereby permitting a straight line discharge from pipe 27 to atinosphere.

Referring now to Fig. 5 the expansion chamber 4 is here shown in communication with the tank 1 through a pipe 28, corresponding in certain respects to the pipe 6 of Fig. 1. The pipe 28 communicates indirectly with the chamber 4 at its upper edge, which is here shown as cut off on the line 32 so as to afford a somewhat larger passage of communication, if desired. In line with ipe 28 is a pipe 29 extending into the chamer 4 from the opposite direction of pipe 28. The pipe 29 is here shown as of larger diameter than pipe 28 and the upper edge 30 thereof in contact with the inside of chamber 4 preferably below the cold oil level or the level of the oil when the apparatus is first filled. The lower edge 2310f pipe 29 is preferably above the bottom of chamber 4 in order that any water or sediment which may be on the bottom of said chamber will not be drawn upwards through the passage between pipes 28 and 29 when the oil in tank 1 is contracted. The relation of the edges 30 and 31 with respect to the chamber 4 may be attained by suitably cutting the end of pipe 29 or shaping it in the desired manner, or the chamber 4 may be suitably shaped. The pipe 29 is provided with an openable closure 10 as described in connection with Fig. 1. It will be noted that in view of the fact that the pipe 29 extends down over pipe 28 that an oil seal is formed for the air in pipe 29 above the oil level. The oil level shown in Fig. 5 is preferably the cold level. When the oil in tank 1 heats up oil will flow upwardly through pipe 28 and discharge indirectly into chainher 4 through the space between pipes 29 and 28. As the oil again contracts it will first reach a level at the lowestedge 33 of pipe 28, after which further contraction of the oil will produce a partial vacuum in the pipe 29 thereby drawing oil up between pipes 29 and 28. It is evident that circulation of oil from tank 1 through pipe 28 to the major part of the oil level in chamber 4 is prevented. the circulation being only to that portion of the level exposed in pipe 28 to the air in pipe 29. This pipe as is evident is not normally in communication with the atmosphere.

The chamber or expansion tank 4 is usually made of cylindrical form as shown in Fig. 3. The latter figure serves to show the rear apparatus of Figs. 2, 4 and In practice it has been elevation of the 5 as well as of Fig. 1.

found that a satisfactory proportion as between the diameter of the cylindrical tank 4 I and the pipe 6 (or 5) is approximately two to one. While it is advantageous to make the tank 4 of cylindrical form and the pipes 5, 6, 21, 27, 28 of circular cross section, other forms may be utilized within the spirit and scope of the invention.

It should be understood that it is not desired to limit the invention to the exact details of construction shown and described, for obvious modifications may occur to a person skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In combination, a casing for electrical apparatus adapted to contain oil, an expansion chamber therefor, a pipe communicating with said casing and extending through said chamber from one side to the other, an openabic closure at the end of said pipe, having an opening within and above the bottom of said chamber, and oil in said casin extending through said pipe and through said opening in the said pipe, said chamber having an opening affording communication between the space above the oil in said chamher and the atmosphere, the space within said pipe above the oil therein being'normally sealed from communication with the space above the oil in said chamber and with the atmosphere by said oil and by said openable closure.

2. In combination, a casing for electrical apparatus adapted to contain oil, an expansion chamber therefor, a pipe communicating with said casing and extending through said chamber from one side to the other, an openable closure at the end of said pipe, said pipe forming the sole support for said chamher and having an opening within and above the bottom of said chamber, and oil in said casing extending through said pipe and through said opening in the said pipe, said chamber having an opening affording communication between the space above the oil in said chamber and the atmosphere, the space within said pipe above the oil therein being normally sealed from communication with the space above the oil in said chamber and with the atmosphere by said oil and by said openable closure.

In testimony whereof, the inventor is affixed hereto.

LOUIS C. NICHOLS.

signature of the said pipe

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