US1712174A - Oil switch - Google Patents

Description

y May 7, 1929.

E, o scHwErrzER OIL SWITCH Filed Oct. 9. 1922 3 sheets-'sheet 1 May 7, 1929. E. o. scHwElTzR OIL SWITCH Filed oct. 9. 1922 s sheets-sheet4 2 www QN EamwzdO .i l l l J May 7,A 1929. 4 E. o. scHwr-:ITZER 1112.174

O IL SWITCH Filed oct. 9. 1922 s sheets-sheet s /Alwin.

Patented May 7, 19.29.

UNITED STATES PATENT' oFFlcE.

EDMUND O. SCHWEITZEB, OIF CHICAGO, ILLINOIS.

OIL SWITCH.

Application led October 9, 1922. Serial No. 593,248.

l'for interrupting circuits of high voltage, or-

large power or both, commonly referred to as an oil switch. Equipment of this sort customarily comprises a suitable receptacle filled with an insulating and to some extent arc-extinguishing and more or less combustible liquid, and mechanical contact making and breaking means immersed in said liquid. While the liquid employed is customarily oil and the switch is, therefore, referred to as an oil switch, it should be borne in mind, that other liquids are available. Throughout the following specification and claims the term oil switch should be construed to mean the type of switch customarily filled with oil,l in contradistinction to such a switch filled with any particular liquid.

rlhere are many liquids more efficient in extinguishing an electric arc than oil, but so :tar as ll am at present aware, no such liquid .-has, up to the present time, been made commcrcially available, which did not have more or less tendency to evaporate (due to its volatile nature) unless the enclosure was sealed, which -is not usually feasible in oil switches; and also to attack and corrode the mechanical contact making and breaking means employed, or which would maintain its value as an insulating medium when exposed to air and moisture. @n thisv account, the use-jofoil is still practically universal in switches of this type. l

When a switch of' this character opens under heavy current flow, the resulting arc vaporizes the surrounding medium. lf that medium is oil, the resulting vapor is inflammable. lt is one of the objects of the present inventionfto provide a liquid in contact with the arc at the time that the switch opens which will evolve a vapor which is not inflammable, and which has, in fact, a fire and arc-extinguishing characteristic. To this end l normally maintain the contacts in a hath of oil for insulating purposes and maintain available for instant replacement either by movement of the liquid itself with respect to the switch contacts orby movement of one or more of the switch contacts with respectto the liquid a body of liquid of suitable character to extinguish the arc and to give. oit a non-inflammable or arc-extinguishing vapor if and when it is heated to the vaporizing point by the arc.

Another object of my invention is to improve the eiiiciency of this type of switch, with particular reference to the features just above discussed.

Another object is to increase the arc-extinguishing power of such switches.,

Another object is to fill the container at the time the switch opens with a substance of maximum eiiiciency in extinguishing the arc.

Another object is to keep the container before the switch opens, with all metal or other parts liable to corrosion, immersed in a liquid of maximum eciency in preventing corrosion and high efficiency in extinguishing the arc.

Another object is to provide excess load and timing means for timing the supply ot special arc-extinguishing Huid to suit the time and other characteristics of the switch and of Ithe system of which said switch forms a part Another object is veniently andA quickly restoring such a switch to initial condition after it has opened.

Further objects land advantages of the invention will become apparent as the description proceeds.

in the accompanying drawings:

Figures l and 2 are cross-sectional views on lines l-'l -O' Fig. 2 and 2 2 of Fig. l respectively, showing the application oi the principles of my invention to one wellknown type of oil switch;

Figures 3 and 4: are similar views, illustrating a different mode of applying my invention to the same switch;

Figures 5 and 6 are sectional views on lines 5-5 of Fig. 6 and tt-6 of Fig. 5 respectively, illustrating the a plication .of a form of m 'invention generality similar to that shown in Figs. 3 and il, to a dierent switch; and

Figure 7 is a fragmentary section showing a modification-of thevstructure of Fig. 5.

ln the embodiment of my invention selected for illustration in Figures l and 2,'

a container l0, preferably of insulating material, is supported in 'a' metal casing comprising side walls l2 and a bottom 14. Surmounting side walls 12 is a casing' 16 to provide for con-v containing the switch operating means (not shown). Insulators 18 project downwardly from casing 16 to insulate and support contact terminals 20. A vertically slidable rod vand out of operative position to connect and disconnect terminals 20.

The switch parts hereinabove described are old and well known in the art, and per se, perform no part of my present invention.

A nozzle 28 having a wide flat mouth as indicated in dotted lines 30 in Fig. 2, is mounted adjacent each set of terminals 20. Nozzle 28 is preferably of insulating material so as not to impair the effectiveness with which the parts inside container 10 are insulated. Any suitable conduit means 32 is provided to deliver iluidfrom a tank 34 or other suitable source of fluid under' pressure. A suitable valve 36 controlled by lever 38 is normally held in closed position by a s ring 40. It may be opened to deliver fluid rom tank 34 through nozzle 28 by the action of a solenoid diagrammatically indicated as a winding 42 having a coil 44.

' Switches of this type are ordinarily designed to open very quickly, i. e., in a small fraction of a second. It will be obvious, that the time required forr solenoid 42 to open the valve, is'merely a question of design involving the power of the solenoid and the Ainertia of the moving parts.. I1have indi-v cated power mains 46 and 48 for operating v the solenoid, the circuit being completed by a relay 50 actuated by the usual current transformer in the main power line. lIt will be obvious that relay 50 may be the same relay closing the circuit for operating the oil switch itself, in which case fluid from tank 34 will always be injected whenever the switch operates, in a predetermined` time relationship depending on the speed of operation of the fluid delivery means, and the speed of the switch itself. f

Alternatively, relay 50 might be independent of thecontrol means for the main switch, and might beset to operate only at a slightly higher value of constant current `flow. than that required to open'the switch itself; but on heavy .surges of current to operate more quickly than the control means for the switch itself. With such a design, a slight permanent excess of current would open the main switch without utilizing any fluid from tank 34, whereas a'heavy surge of current,

liable to cause .severe arcing 1n the switch,

would resultin the delivery 'of fluid from tank 34 even.- before the switch y contacts separated.

lheiluidsl at present contemplateusing,

are oil in the switch itself, and a suitable j arc-extinguishing fluid in tank 34, such es carbon tetrachloride, or the liquid disclosed in U. S. Patent 1,319,907, granted October 28, 1919, to myself and Nicholas J. Conrad. It will, however,- be' obvious that in its broader aspects, my invention is not limited to the use of any particular fluid or fluids. Referring now to Figures 3 and 4, I have illustrated, in connection with the same switch shown in Figures 1 and 2, small cartridges or containers 52 and 54 removably -fastened in place as by clip 56, and immersed in the contents of the main bath. Each cartridge is provided with a destruct-- ible and renewable window or partition 58 and 60 respectively, so positioned that if the arcing becomes at all serious, the heat thereof will rupture and destroy the window and release the contents of the cartridge to flow down and extinguish the arc. In the case of oil and a chlorinated hydrocarbon, the flow will be down, as the specific gravity of the extinguishing fluid will be from two to four 'times that of the oil, depending on the particular oil and extinguishing fluid selected. i

'Window 58 is arranged horizontal, close to the base of one lset of contacts 20 and window 60 is arranged in a vertical plane. It

lwill be apparent that a large number of different positions may be provided.

Switches of this\ type are usually ins ected, and, if necessary, repaired or partially replaced, eachtime they open. Afterl 'lol 'nsv

after it has once opened, until it is possible to send an inspector to put it in condition for further continuous service.

Referring now to Figures 5 and 6, I have illustrated one terminal of another well known t pe of oil switch. In this construction an imperforate shell 62 contains the main bath, and under normal conditions valso carries the current. When an overload occurs, an ordinar contact switch (not shown) opens the circult through the shell, forcing currentto flow thereafter through the central rod 64, from socket 66 to cross-piece 68.

. Of course, a very small fraction of a second after the ordinary disconnecting switch has opened, cross-bar 68 is forcibly raised, lift- \ing rod 64 out of its socket to finallyinj terrupt the flow of current e In ap lying the principles of my invention to t is type of switch I preferably provide a.A unitary holding rame, comprising three uprights 70, preferably of wood, supporting an insulating annulus 72 by means 130 clamped against withdrawal by expanding a portion of the thread by means of-wedge 90. The receptacles, or cartridges 92 are preferably three in number, and are spaced uniformly about the axis of rod G4, each cartridge having an inwardly facing window 94 ne'r its lower end. If the are drawn in opening the switch follows Vthe end of rod 64 above annulus 72, windows 94 will immediately be destroyed, and the arc-extinguishing fluid in all the cartridges will be simultaneously poured inward directly into the arca After the switehihas once opened, the inspecter can relieve wedge 90 andremove shell 62. The entire supporting framework for the cartridges, can now be simply lifted out, and put back inq place with lnew car.- tridges, or, incase the frame itself has been too much damaged by the arc, a new frame can be supplied. The entire attachment necessitates no "change in the structure of the switch, and can be readily applied to switches now in use.

Referring now to Figure 7, it' will be seen that I may curve window 94 outwardly almost into Contact with rod 64, and provide the rod with a horn 96 positioned in alignment with each window. `When this construction is employed, horn 96 will shatter window 94 before the are reaches the window, and further movement of the rod will draw the end of the arc directly through the are-extinguishing fluid liberatedby the. de-

struction of the windows.

Without further elaboration, the foregoing will so fully explain the gist of my invention, that others may, by applying current knowledge, readily adapt the same for use under various conditions of service, without eliminating certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be deiined and secured to me by the following claims.

I elaimz- 1i. In an oil switch the method of interrupting the elec-tric 'are which is formed upon separation of the contact, which comprises displacing the oil in contact with the are by a non-iniammable arc-extinguishing liquid. f

2. The method of extinguishing an are' in a'body of oil which comprises displacing a part of the oil by another liquid of greater .are-extinguishing capacity.

3. In an oil `'switch having its contacts submerged in an o-il bath, the method of interrupting the fiow of current. which comprises separating the-contacts, drawing an are in the oil, and by the heat of said are releasing a body Aof non-combustible liquid of are-extinguishing characteristics into contact with the are.V a

4. In an oil switch having its contacts submerged in an oil bath, the method of interrupting the flow of current whi h comprises separating the contact, drawing an are in the oil, and upon the separation of the contacts displacing the oil in contact with the are by a non-combustible are extinguishing liquid.

5. In an'oil switch, a tank for oil, a stationary contact and a cooperating movable contact, said contact being submerged in the oil in said tank, means for moving the movable contact out of engagement with the stationary contact, a non-infiammabile liquid and means effective upon the separation of the contacts for displacing the oii about the Contact by the non-infiammabie liquid.

liquid, contacts separably engaged in said liquid, and means for introducing a liquid of different character into said body of liquid, said means being effective responsive to the separation of the contacts.

7. In combination a tank, oil in the tank, circuit interrupting means submerged in the oil, and means for introducing a non-infiammable liquid into the oil adjacent the circuit interrupting means.

8. In combination, two separate bodies of liquid, means for opening a circuit at a point in one liquid body, and means .operated only when said opening means also operates, to liberate the other liquid.

9. In combination with the bath and circuit interrupting means of an oil switch,

,of said receptacle, and positioned to be destroyed by the are when. the switch opens.

1l. In combination with the bath and circuit interrupting means of an oil switch, a receptacle in said bath, an arc-extinguishing medium in said receptacle, a destructible partition forming part of said receptacle and positioned to be destroyed by the are when the switch opens, and mechanical means for rupturing said partition before the are reaches it.

6. In combination, a body of insulatin{2; 9f }m 12. In combination with the bath andcircuit interrupting means of an oil switch, a receptacle containing a non-inflammable arcextinguishing liquid for extinguishing the arc formed at the circuit interrupting means,

and a support for removably mounting said receptacle in said bath.

13.4 In combination with the bath and circuit interrupting means of an oil switch. a supporting frame work .removably mounted in said bath, and a receptacle containingr a non-inflammable arc-'extinguishing liquid in said bath supported on and removable with said frame work.

14. In an oil switch employing'separable contacts and an oil bath surrounding said contacts, the method -o interrupting an are between said contacts .which comprises injecting an inert arc-extinguishing liquid into the bath when the switch opens.

15. In an oil switch employing separable contacts and an oil bath surrounding said contacts, the method of interrupting an arc between said contacts which colnprises injecting an -arc-extinguishing liquid into the bath to form a temporary bath which will evolve a non-inflammable vapor.

16. In an oil switch having a pair of con-.-

tacts movable with respect to each other to open an electric circuit, the manner of, pre-l venting damage to the switch which comprises normally submerging the contacts in a bath of insulating oil when the contacts are ,closed and re lacing said oil bath in partlby a bath ofp a non-inflammable arcextinguishing liquid when the contacts are movedto open position.

17. In an oil switch employing separable' contacts and an oil bath surrounding said contacts, the method of extinguishing an' arc between said contacts which comprises moving a body of arc-extinguishing liquid other than the oil of the bath acrossA the path of the arc as the contacts separate.

18. In combination with the batln and circuit interrupting means of an oil switch,-

as to be destroyed by the arc when the switch is opened to permit the liquid to flow out of said receptacle and into the path vof the arc.

19. In an oil switch having its contacts submerged in an oil bath, the method of interrupting the low of current which comprises separating the contacts, drawing an arc in the oil, and by the heat of said are releasing a body of non-inflammable arc-extinguishing liquid having a specific gravity higher than that of the oil bath from a point above the arc, so as to permit it to How into contact with the arc.

20. In an electric switch, two receptacles containing insulating liquid having diiferent insulating properties, means for drawing an arc in the liquid in one of the receptacles, and means for pouring the liquid from the other receptacle into the arc to quench the same. l

21. The method of breaking an electric circuit which consists' in drawing an arcl circuit which consists in drawing an arc in an insulating liquid and in quenching the arc by displacing the liquid adjacent the.

the arc by an insulating liquid having a low boiling p oint which, upon vaporizing, cools the are and temporarily produces a region yof high pressure adjacent the arc.

23. In combination, a tank, a body of oil in the tank, circuit interrupting means vsubmerged in the oil, a receptacle mounted `within the tank, said receptacle containing a'body ofnon-inflammable arc extinguishin liquid ofv different insulating-characteristics and greater arc extinguishing. properties than' the oil, and means for injecting said non-inflammablearc extinguishi liquid into the tank and adjacent the circult interrupting means. v

In wltness whereof, I hereunto subscribe my name this 7 day of October, 1922.-

# EDMUND o. senvimirznn`

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