US1872510A - Lightning arrester - Google Patents

Description

Ag, 16, 1932. E. QSCHWEWZER 1,872,510

'LIGHTNING ARRESTER Filed May 23. y'1927 2 sheets-sheet 1 ug- 16, 1932 E. o. scHwElTzER LIGHTNING ARRESTER 2 Sheets-Sheet 2 Filed May 25, 1927 Patented Aug. 16, 1932 PATENT OFFICE `r`IELDMUND'O.SCHWIEI'IZER, 0F CHICAGO, kILLINOIS LIGHTNING ARRESTEB Application ma nay as, 1927. `serieu No. 193,443.

My invention relates to currentl interrupting devices, and while the invention is particularly useful' in connection withy lightning ,arresters ,employed to provide a path to ground'for excessiveftransient voltage conditions` on powercircuits and the "like, and I have sliownthe preferred' embodiment as employed in such use, it is not to be limited to such use. i n `I am aware that itis old to provide a horn gap arrester with one horn'connected directly to the line andthe otherv ounded through a water resistance for limiting the dynamic flow. In the preferred elnbodiment of vmy invention I employ those elements but now arranged in a novel relation and for a novel purpose. l, f

`The current flow which maintains the arc is employed at the same time in .the water o resistance to generate a vapor which is usefully employed `to extinguish thearc. y

It is desirable "to project the vapor with considerable violence yinto the space where,

l the arc is maintained so as to secure both a quick andcomplete yoccupation of ythe space at one time, and alsotosweep the arc away from the position where itmaintains itself. The vapor should be permitted to expand to become dry and to increase the velocity of the same. The manner in `which this is secured and the apparatus by kwhich it may be done is explained more in detail in the following specificatiomin which I have illustrated an embodiment of the invention in order to teach those skilled in the art how to construct and operatethersame.L

Ink the drawings,y Fig. 1 is adiagram of a system embodying my invention; s 4o n Fig. 2 is a similar diagramfof a modification of the same; i n n I Fig. ,3 is a diagrammatic view of two 'elements embodying vmy invention connected in series; and

'66 `Fig. 4 isa dia-gram of another modification. 4

Referring now to Fig. 1, the line conductor 1 is a phase conductor ofa power distribution or transmission system, and theflightning arrester 2 of my invention is connected to said on insulators 8 and 9 on the tank 10, which tank may be made of suitable sheet metal,

such as boiler plate'or the like, to withstand considerable pressure. The horn electrode 5 6 is connected to the line wire 1 and is there- 'fore live at all times that there ispotential on the line wire 1. .The hornelectrode 6 is connected to ground at 3 througha water resistance contained in the tank 10. This water resistance comprises a body of water 11 which is maintained normally 'at a level, such as indicated at 12, through the medium of a float controlled valve 13 .connected in a supply line 1 4, as for example from the city water mains. The float chamber 15, which controls the level in the tank 10, is connected to said tank 10 through a pipe connection including the check valve 16. The circuit of the grounded electrode 6 includes a pair of spaced electrodes 17 and 18 within the tank 10 and preferably disposedv in such relation within the tank that the gases and vapors, dueto the passage of a current through the water between these electrodes, is quickly freed at the surface of the' water and' may discharge through the discharge pipe 19 and nozzle 20, which nozzle is disposed adjacent the minimum gap 7 of the horn electrodes 5 and 6. 90 This nozzle isfpreferably a flattened oblong opening, such as would be produced by squeezing together the two sides of a pipe to form a relatively narrow slit asr anoutlet. The pipe 19 and nozzle 2O are preferably 95 made of a piece of bakelite or other suitable insulating material. The gases and vapors kwhich are formed by the passage of current from the electrodes through the water between them, rise to the upper part of the tank 10 ma and are discharged through the pipe 19 and nozzle 2O into the gap between the horns 5 and 6 in such a manner as to release the steam and gas at a point where it will occupy the space in which the arc must be maintained.

" rIlhe nozzle 2() forms. a restriction producing a her velocit;v of the 'apor when it emerges the open air and flows into the horn gap. Since the vap r is projected into free atmosphere from the nozzle 20 it has an opportunity to expand and become dry and, therefore, highly eiicacious for extinguishing the arc. rllhe increased velocity produced by the expansion is highly desirable. The greater the power flowing through the arc, the greater will be thqtendency to project gas and vapor into the space where the arc is maintained to extinguish the same. The action of the vapor and gases discharged from the nozzle 2O is two-fold. First, the violence of discharge tends to blow the arc upwardly along the horns 5 and 6, stretching the same and tending to break the arc. Second, the gases and vapors are relatively high in insulating quality and tend, by Vtheir presence in the space in which the arc is maintained, to

cool the arc and to increase the resistance of passage ot' the arc through the space to such an extent as to extinguish the same.

The operation oiI the device is remarkably quick, as has been demonstrated by photographic records o the operation of the same. rI'he initial rush of current from the line 1 finds a relatively easy path to ground, excepting the air gap at 7. It the disturbance is great enough to break down the air gap, the current iiows to ground through the water gap 17-18, there releasing, by the heat of current flow, a vapor which is discharged through the nozzle 2O and which quickly ein.'

' breaks the arc at this point.

I have shown the lower end of the tube 19 as extending adjacent the surface of the water. It is within my invention to extend the same down to a point below the surface of the water for the purpose of securing av puff or elast of greater violence. The manner in which this is accomplished will be apparent from the fact ythat if the lower end of the pipe 19 is extended to a point below the normal level 12, the-pressure in the upper part of the tank 10 must be raised to a point great enough to eject a slug of water before steam can enter the pipe 19, and as the pressure builds up with great rapidity in said tank 10, such pressure is not released until it has reached a relatively high point to give a violent pull or blast. The linitial discharge oi: a slug of water has no adverse influence on the operation of the device because no conducting body or surface connects the horn electrodes 5 6 and. the water or the interior electrodes 17-18.

I have shown the ground circuit as including the wire 21 led into the interior of the tank 10 through an insulator 22 and there connected to the electrode 18. The electrode 17 is connected through a wire 23 extending through an insulator 24 to ground at 3. If desired, the bank itself may be grounded and may comprise one side or electrode of the water gap.

It will be observed that the electrodes 17 and 18 are projected above the normal level of the water 12 and where this is done, I find that the vapor appears to be formed mostly at the surface and is thereby released with great rapidity. The check valve 16 prevents discharge of water out of the tank 10 and, after an operation of the device to extinguish an arc, any water which has been displaced by the action is replaced from the supply line 14 to the float controlled valve 13.

If desired, a heater may be employed during cold weather to maintain a suitable temperature of the water in the tank 10, and the water may be changed periodically, as byV draining out a certain part of the same through a drain connection 25.

In Fig. 2 I have shown a. modification in which the electrodes 17 and 18 are disposed within a` supplementary chamber 27 within f the tank 10. This supplementary chamber 27 is connected at its upper end to the pipe 19 and nozzle 20, and is open at its lower end to the tank 10, a suitable check valve 28 being shown as controlling disconnection, but this check valve may be dispensed with due to the taniping action of the body of water in the tank 10. The level 12 stands normally the same in the main tank 10 and in the supplementary chamber 27, and the electrodes 17 and I18 are arranged, as above referred to in connection with Fig. 1, adjacent the surface of the rater, but within the chamber 27. Upon the breaking down of the gap 17 and the flow of current through the wire 21 from electrode 18 to 17 and to ground through wire 23, vapor is generated within the chamber 27 and is immediately expelled through the pipe 19 and nozzle 2() into the gap between the horn electrodes. This results, as before,

in a quick and positive snuiling or extinguishing action.

In Fig. 3 I have shown how a'plurality of such arresters may be connected in series v'here the voltage. to be controlled is greater than would be within the scope of a single unit. The two units shown in Fig. 3 are identical and are substantially of the same general character as shown in connection with Figs. 1 and 2. A supplemental chamber 27 is employed at the lower endof the tube 19, which in this case is extended down to such chamber 27 considerably below the level 12 of water in the tank 10. The electrodes 17 and 18 are disposed in said supplemental chamber 27 The lower end of the chamber 27- is, in this case, left open to the space within the tank 1() outside of the chamber 27. The action of each unit is the same as previ- .v ,5.5 as satisfactory as projecting the vapor itself ously described, the two units operating sir`multaneously.-` The chamber .27 being disposed at a considerable depth below the level 12,-nisnorma1ly full of water as is' the lower part ofthe pipe-19. As a result, the generation of vap'orand gases in the chamber 27: is `.not immediately released, vthe same being 5 held under the head of liquidin the pipe 19 untill thek same is ejected, whereupon, the

'gas and vapors are released ,wahieonsidee able' .violence-iat the nozzle 20, 1 i

n ,I have shownthe circuit as insulated from the tanks, 10-10,- kbut,-'as previously explained, the tanks being preferably of metal, 'maybe included asa partof'the circuit. I

find it desirable to support the tanksfon insulatorsfpartic ularly where a plurality are `used as shown in Fig. 3. f

In-Fig. 4 I have shown a modification in which the tank 10 is provided 'with a tube 430 which projects down through the top wall ofthe/tank. `'Ihis tube 30 communicates at its lower end with the interior of thetank l0, in rthisr case `a check valvey 31 being eml ployed, said check valvelpr'eferably being formed of metal. A rod 32, extending lfrom the horn, projects down inside ofthe tube 30,

forming an electrode;` The tube 130 is preferably formed of insulating material andhas formedat the water'gap and discharge' it into the airfgap. By' this means the saine flow of energy whichpasses through the air gap also passes through the watergap and, as is'well known,fthe greater the enerefv beingreleased in an arc`,'r the:niore diicult itis to extinguish, but, at the same time, the more energy passing through the water gap, the greater power' does it have to perform the act of extinguishingir the arc.

I have tried the experiment of proiecting only water into the horn gap and I find that, within the normal limits of energy available, the flashing of the Water into steam within the space in which the arc is formed, is not after it is formed. I consider that the reason for this is, first, that it is more diicult to secure the saine velocity of flow of the heavier liquid than it is of the lighter vapor; second, n

'l Water is maintained. This is not true, howvter resistance.

ever, where a stream of gas or vapor ispro- Jectedy into the horn gap, as it has already been transformed from a. liquid conducting state to a gaseous non-conducting state, and 'the discharge of vapor may continue long after the arc has been extinguished without again establishing the arc'.` This would not be vtruc in the case of water. f

f fThe water` which I 'have employed in my operation of the device abovedescribed, is city tap Vwater taken from the Chicago mains. ,Itcontains suflicient mineral to, provide the necessaryr conductivity without too :great conductivity for my purposes. Itis obvious to those skilled in the art that the size `and spacing of the electrodes 17-18 is dependent upon the voltage and energy ava-ilable and the conductivity of the liquid'and like 'factors which are known to aii'cct a waf vIt is to be observed that the initial path for the discharge of the transient voltages lhas relatively great capacity and yet includes considerable resistance. The resistance vis great enough to prevent excessive flow of dynamic current, but, at the same time, the resistance to the flow of dynamic current is through a nozzle into a free atmospheric space, the nozzle being directed into the space between the horn electrode where the arc occurs. The nozzle causes an increased velocity and secures drying of the vapor by a speedy expansion and gives the expanding stream of vapor the desired direction in free space.

I do not intend to be limited to the details shown and described. Y

.I claim: f y

1. In combination, a spark gap, a relatively small liquid tank'having a pair of electrodes, a kbody of water in the tankdisposed between said electrodes, said electrodes being connected in series from the spark gap to ground, a nozzle `connected to the tank and spaced from and directed into the spark gap for conducting vapo-i' from said tank and discharging the saine into the spark gap, and av relatively large tank within which the small tank is immersed and which supplies water to the small tank.

2. In combination, a spark gap comprising a pair of electrodes, a chamber, a pair of electrodes in the chamber, a body of Water in said chamber between the electrodes, a discharge connection from the chamber leading to the spark gap tor discharging vapors released in said chamber into the spark gap, and a tank surrounding said chamber and communicating therewith to maintain the chamber full of liquid` 3. In combination, a main tank, a chamber Titliin said tank communicating with the main tank, electrodes in said chamber, a spark gap in series with said electrodes, a discharge conduit leading from the chamber to the spark gap, and a body of liquid in said tank and in said chamber between the electrodes.

4. In combination, a spark gap comprising free horn electrodes in the open atmosphere, insulators for supporting said electrodes, a nozzle extending toward the gap between the electrodes, but out ot contact with the electrodes and having a restricted opening directed into the space between the electrodes, Water chamber connected to said nozzle, and a pair or" electrodes in the Water chamn 'ber connected in series with the horn electrodes.

5. In combination, a spark gap, a tank adapted to contain a conducting liquid, electrodes adapted to be connected by the liquid in the tank, said spark gap and electrodes being connected in series relation, said tank having a restricted outlet spaced from the spark gap and adapted to direct a How of vapor into the spark gap to extinguish an arc, there being tree expansion space between the said outlet and the spark gap.

6. In combination, a spark gap, a tank containing a conducting liquid, a pair of electrodes in the tank, said electrodes extending above the level of the liquid in the tank and being connected in series relation With the spark gap, and a nozzle for projecting vapor from the tank and produced from the liquid in the tank into the spark gap.

7. In combination a closed tank adapted to contain liquid, means for passing an electric current through the liquid to decompose and vaporize a portion thereof, an exposed spark gap mounted for permitting the free passage of air into and away from the region of the gap to tend to maintain the pressure at the gap at atmospheric pressure, said gap comprising a pair ot exposed electrodes, means tor supporting the saine, and means for violently eject-ing the products of the decomposition and vaporization ot the liquid into the open atmosphere in the region of the spark gap, aid means including a nozzle of insulating material extending substantially to the spark gap and directed into the region of the gap.

8. In combination a closed tank adapted to contain liquid, means for passing an electric current through the liquid to decompose and vaporize a portion thereot, an exposed spark gap mounted for permitting-the free passage of air into and away from the region'of the gap to tendto maintain the pressure atfthe gap at atmospheric pressure, said gap comprising apair of exposed electrodes means for supporting the same,means forviolently ejecting the products of the decomposition and vaporization of the liquid into the region of the spark gap, said means including a. nozzle of insulating material extending substantially to the spark gap and 'directed into the region of the gap, andsaid spark gap supporting means being mounted jonf the tank.

9. Arc interrupting means including a pair of arcing members and a steam generator comprising a relatively large Water chamber having a. relatively small supplementary chamber therein and extending above'and below the Water level in the large chamber, said supplementary chamber having an opening for permitting the entrance of Awater therein from the large chamber, means within the small chamber for generating steam, and a steam outlet for said supplementary chamber, said outlet being directed into the region of the arcing members.

10. Arc interrupting means including a pair of arcing members and a steam generator comprising a relatively large water chamber having a relatively small supplementary chamber therein and extending below the water level in the large chamber, saidsupplementary chamber having an openingfor permitting the entrance of Water therein from the large chamber, means Within the small chamber for generating steam, a steam outlet for said supplementary chamber, said outlet being directed toward the arcing members, and means for checking the ex ulsion of Water through said first mentione opening upon a rise in pressure within the supplementary chamber.

In witness whereof, I hereunto subscribe my name this 18th day of May, 1927.

EDMUND O. SCHIVEITZER.

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