US1706782A - Electric switch - Google Patents

Description

together, suitable packing Patented Mar. 26, 1929.

UNITED STATES PATENT "OFFICE.

JOHN D. HILLIABD, OI SCHEN'ECTADY, H YORK, ABSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION 01' NEW'YOBK.

ELECTRIC SWITCH.

Application fled larch 17, 1924. Serial No. 699,698.

My invention relates to electric switches for the control of high potential circuits and an object of my invention is to provide an improved construction of switch for this purpose in which the contacts separate In a chamber filled with a suitable gas.

My invention will be better understoodby reference to the accompanying specification and drawings and its scope w 1ll be pomted out in the appended claims.

In the drawing, Fig. 1 shows a vertical section of a switch involving my invention, and Fig. 2 is a fragmentary detail on a different plane. A tight chamber or receptacle 1 is formed by joining together two open ended casings 2 and 3. Each casing has a flange 4 throu h which extend securing bolts 5 for secure y clam ing the casings ing employed between the flanges to produce a gas tight joint. The casing 2 is preferably lined w1th insulation as shown for example at 6.

The switch contacts and operating mechanism therefor are mounted upon a bracket 8 supported as shown from the casing 3, the stationary contacts being carried on lnsulating pillars 9 secured to the bracket 8 and the movable contact 10 and operating mechanism being carried on an insulating pillar 11 also secured to the bracket 8. An operating rod 12 having a section 13 of insulation,

., as for exam le wood, actuates the movable contact mem r through ,a to gle mechanism 14 in the common and well own manner. The switch is preferably rovided with areing contacts 16 with whic a blow-out magnet17 is associated. This magnet may be of any common form and may e connected in the circuit in any one of a variety of ways well known to those skilled in the art. A barrier 18 is shown for shielding the sides of the casing from the arc and in the case of a multiple phase switch for separating the arcingcontacts of the different bases in which case the barrier would pre erably be elxtended to separate the main contacts as wel The 0 erating rod 12 is shown carrying a disk 20 tween which and the casing 3 is a compression spring 21 for causing a quick opening of the switch. Where the rod 12 passes through the casing 3 a stufling box22 is provided to make the connection s and oil tight. The leads 24 of the switch are carried through the bottom of the casing 3 by means of insulator bushings 25, the bushings being shown secured in the casing bya clamp with suitable packing and the leads secured in the bushings by cement to prevent the escape of gas or oil from the chamher. The chamber is filled for the most part with a gas which has a high dielectric strength and good heat conductivity and which is not decomposed by the heat of the are between the contacts. Hydrogen has been found to be admirably adapted to fulfill the above conditions. Chlorine has also been found to have good interrupting qualities and may be used as the surrounding medium but when so used it is essential that the insulating parts contain no moisture that is, they cannot be of cellulosematerial unless the material is impregnated with asubstance not attacked by chlorine or hydrochloric acid. The gas is preferably confined under pressure, good results having been ob tained with a pressure of about thirty' pounds to the square inch. To facilitate sealing the chamber against leaka e of gas at the various openings thereinan particularly'for the urpose of providing a means for visibly in icatin the presence of a leak should such occur, t e lower portion of the chamber is filled with a liquid 26, as for example oil, carbon tetrachloride, or mercury.

It will be noted that the walls of the upper casing 2 project down into the lower casing 3 so that in case a leak should develop at the joint between the two casin s considerable liquid would have to esca e fore the the level was lowered suflicient y to permit the gzs to escape. A valve 27 is secured in the ttom of the casing 3 .to which valve the gauge 28 may be detachably connected. Pipe 29 controlled by the valve 30 extends through the side of the same casing, the innerend of this pipe being turned at right angles and being of suflicient length to reach above the oil surface, as shown by dotted lines on the drawing. In order that the inner end of this pipe may normally be kept below the liquid surface to facilitate the detection of a leak in the .valve 30, the pipe is rotatably mounted in the wall of the lower casing and the connection made tight by with gas when t bolts 5 from the flanges 4 and ofi the up er casing 2.

11 order com letely to fill the chamber he apparatus is initially set up and to refill the same after being opened for inspection or repair suitable means must be provided for first expelling substantially all of the air contained in the chamber.

This is made possible by the tube 35 which the valve 37 and in order that as little air be left in the chamber as possible the top thereof is provided with an upward PI'OJBCUOII 40 forming an inverted sump into which the valve may be pushed while oil is being introduced into the chamber through pipe 29 to expel the air. When the oil reaches the top and begins to flow down through the tube, 35, the tube is lowered as far as possible, the valve 37 thus sealing the opening through the tube. The gauge 28 may then be removed and the oil allowed to escape through tube 29 and valve 30 while hydrogen is admitted through the valve 27. When ,the oil level is lowered to the desired heightwhich for instance may be determined by the angular position of the pipe 29 when gas begins to come out with the oil, the valve 30 is closed and the desired pressure of gas introduced through the valve 27 Obviously it is not material through which of the valves 27 or 30 the oil is withdrawn and the gas is admitted. It may be found more convenient in the final filling of the chamber with gas under pressure to introduce the gas I through valve 30 so that the pressure may be read on the gauge 28.

Where the gas used is hydrogen or chlorine no provision need be'made for the escape of gas generated by the operation of the switch, as is the case for example with present oil switches, since at ordinary interruptions there is no permanent dissociation of the hydrogen or chlorine nor combination with any other element to form a gas. An increase of pressure is of course produced by the heat expansion of the gas but this returns to the original value as the gas cools.

To provide against the formation of excessive pressures due to heat expansion of the "enclosed gas when abnormally heavy currents are interrupted I have provided a cushion tank 42 connected with the chamber 1 b means of a pipe 43 which is controlled y a valve 44. The pipe 43 may be securely fastened into the bottom of the casing 3 as by welding and maybe of such lengt within the chamber as to just reach above the level of the oil. The principal function of the valve 44 is to isolate the cushion tank durin the process of expelling air from the cham r and filling the same with gas.

I do not claim broadly as my invention an electric switch whose contacts are enclosed in a chamber filled with hydrogen, such invention being described and claimed in the copending application of Chester W.

Rice, Serial No. 699,660, filed March. 17, 1924 and assigned to the same assignee as the present application.

While I have described only one embodiment of my invention, I do not wish to be limited to the particular form shown and described as it will be apparent that many modifications therein may be made withoutdeparting from the scope of my invention as set forth in the appended claims.

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

1. An electric switch comprising a fluid tight chamber containing a gas under pressure, switch mechanism mounted in the chamber and comprising contacts separable in the gas,contact connection and a switch operating member extending through the lower portion of the chamber and a liquid in the chamber for indicating a leak therein 3. An electric switch having a chamber adapted to enclose a gas under pressure comprising a lower casing, switch mechanism supported thereby, an operating member therefor passing through said casing, a sealing liquid in. said lower casing, an upper inverted casing for enclosing said mechanism and having its mouth extending below the level of said liquid, said casings having co Ill operating flange portions whereby they may be secured tightly together.

4. An electricswitch comprising relatively movable contacts and operating mechanismtherefor, a lower casing for supporting said contacts aud operating mechanism, current leads and an operating member passing through said casing, an imperforate upper casing enclosing said contacts and operating mechanism and secured to said lower casing, a sealing liquid in said lower casing extending above the mouth of said upper casing, and means extending through said lower casing for introducing and withdrawing gas.

5. An electric switch comprising a fluid tion whereby by giving the pipe an angular movement the inner end may be raised above the level of the'liquid or depressed below the same. I

6. An electric switch comprising a fluid Patent No. 1,706, 782.

'JonN 1). amino.

CERTIFICA'IE OI" CORRECTION.

'quid being removable 'to' a normal level to form a-seahavalve seat beneath the normal level-0f said liquid} and'avalve' on said tube adapted to engage said seat and close said 'L An electric switch comprising a fluid tight chamber containing a gas-under pres; sure, switch elements mounted in said chamand adapted to reach to the top thereof, said tight chamber containing gas under pressure, 7 h

switch elements therein; :a pipe extending through the lower portion of said chamber 5 and asealing liquid in the lower portion-of said chamber, said pipe having an ofiset poltube ber asoparate fiuidtight expansion chamm her for the expanded gasfrom saidfirsti chamber and means'providi'ng a com'munication between said chambers.

my handthis 15th dayof March;

JOHN D. HILLIARD.

Granted March 26, 1929, a

It is hereby certified that-error appears in the printed'specification of the above numbered patent requiring correction as follows: Page 2, line 92, claim '1, for the word "connection" read "connections"; and that thesaidLetters Pate'nt ahould be read with this correction therein that the same may conform to .the record of thecaac in thePatc'nt Otfice.

Sign! III! Mild till! 23rd (ll! of April. A, 1929 Acting Commissioner of Patents.

Inflwitness whereof, I have hereunto set

Images