US2626368A

US2626368A - Electrical discharge device of the arc expulsion type

Info

Publication number: US2626368A
Application number: US158181A
Authority: US
Inventors: Clifford W Petersen
Original assignee: McGraw Electric Co
Current assignee: McGraw Electric Co
Priority date: 1950-04-26
Filing date: 1950-04-26
Publication date: 1953-01-20
Anticipated expiration: 1970-01-20

Description

Jan. 20, 1953 c. w. PETERSEN 2,626,368

ELECTRICAL DISCHARGE DEVICE CF TEE ARC EXPULSICN TYPE Filed April 26, 195o 5 FIGB. FIG.4.

CLIFFORD W. PETERSEN INVENTOR.

AT ORNEY Patented Jan. 20, 1953 ELECTRICAL DISCHARGE DEVCE GF THE ARC EXPULSION TYI-E Cliord W. Petersen, Wauwatosa, Wis., assigner to McGraw Electric Company, Milwaukee, Wis..

corporation of Delaware Application April 2.6, 1959, Serial No. 158,18l

(Cl. Slg-2.31)

5 Claims. l

This invention relates to an electrical discharge device as utilized for the protection of distribution systems and electrical equipment from excessive voltage, and more particularly to a device such as this of the arc expulsion type.

The present invention is incorporated in a housing substantially identical to the housing shown in Patent No. 2,429,533, granted October 21, 1947 to Herman O. Stoelting.

The operation of the novel discharge device is similar to that disclosed in the cri-pending application of Russell A. Wood, Serial No. 157,542, filed on April 22, 1950, and assigned to the same assignee as the present invention. That is, the 'arc is caused to travel from a line electrode to the ground electrode through an arc extinguishing medium including a plurality of adjacent lateral passages joining these electrodes. These lateral passages have been found to be very advantageous in providing an arrester with a high surge capacity and low spark-over voltage. Low spark-over voltage is very important to proper functioning of any arrester in order to provide immediate protection to associated apparatus by placing the arrester in action before any surge voltages become of such magnitude that would threaten injury to the protected apparatus. lThe requirement of high surge capacity is essential to offer protection to associated apparatus no matter the magnitude of the surge potential.

In addition to the above requirements, a discharge device must be capable of operating for a relatively long life period for economic and other reasons. One of the greatest detrimental influences on the life of an arrester is the delcopious amounts of un-ionized gases from the action of the high temperature arc on the :arcextinguishing medium contained within the arrester housing. The 11n-ionized gases aid in the expulsion of ionized gases that provide a supporting atmosphere for power current which tends to follow the surge at or before the first normal power current zero. Naturally, if these gases are confined in any manner they will tend to erode the confining surfaces.

It is therefore a primary object of the present invention to provide a protecting discharge device of the expulsion type for electric lines that incorporates the advantageous principle of providing a plurality of adjacent lateral arcing passages between arcing electrodes, and in addi- "fiston, to :provide a novel arrangement for rapid lll 2 expansion of accompanying arc-extinguishing gases thereby considerably reducing the deleterious eroding action on the wall surfaces of the extinguishing media by these hot, high-pressure gases.

Another object of the present invention is to provide a discharge device that will extinguish all excessive voltage surges, whether generated by heavy line surges from lightning, etc., or by low current arcs created by momentary overloads.

A further object is to provide an electrical discharge device with a series of lateral arc-extinguishing passages between spark-over electrodes, said passages intersecting with a multiplicity of transverse openings in the arc-extinguishing material to provide greater dispersion of un-ionized gases or vapors created in order to further aid in the extinction and expulsion of the surge arc.

A further object of this invention is to provide an electrical discharge device with an arcing chamber that is simple in structure and easily manufactured, and which may be easily modied to protect electrical apparatus of varying capacities.

These and other objects will be apparent; from the following description taken in connection with the accompanying drawing and claims forming a part of this application, in Which- Fig. l is a longitudinal view, partly in section, of an expulsion type lightning arrester disclosing the preferred embodiment of the present in- Vention;

Fig. 2 is a cross-sectional view taken on line 2 2 of Fig. 1 illustrating the preferred arrangement of the concentric telescoped tubes with the openings to the walls alternated to provide greatest diffusion of un-ionized gases and vapors;

Fig. 3 is a longitudinal sectional view of one of the tubes of the telescoped arrangement of concentric arcing chamber tubes illustrating the preferred wall opening and notching arrangement;

Fig. 4 is a longitudinal sectional View of either of the concentric arcing chamber tubes positioned in adjacent manner to the tube shown in Fig. 3;

Fig. 5 is a top elevation View of the perforated washer separating the sections of concentric arcing chamber tubes;

Fig. 6 is a top elevational view of the lower contact vent plug, which concurrently acts to retain the concentric tubes and also to permit gases to escape.

As suggested above, an embodiment of this invention may be contained within the arrester housing disclosed in the Stoelting Patent No. 2.429533. This arrester housing is adaptable for the protection of any of many electrical devices auch as transformers, capacitors, voltage regulators, etc. Also, the novel arrester may be conveniently mounted on a cross-arm, the upper terminal being electrically connected to one of the terminals or the equipment to be protected, or alternatively to a line wire, the lower terminal being connected to ground.

The housing portion l, illustrated in Fig. 1 is preferably of a ceramic material, but also may be conveniently made of other insulating materials. The housing is provided with a chamber 2, which is open at the lower end and closed at the upper end, except for the aperture 3.

The aperture S accommodates a stud Li which rinly supports a petticoat insulator 5 at its upper end. The hrm support is maintained by providing a chamber in the insulator `5 for receiving a binding material Ei, such as cement, or other similar material, for securing a metal itting 1. This ttingis provided with internal threads for engaging with the upper threaded portion of the stud A gasket il is provided as a moistureprooi seal. An elongated electrode or arcing horn 9 is clamped between the housing i and the insulator 5. The electrode 9 is simultaneously clamped in place and electrically connected to the stud li by means of engagement of the stud and the fitting l'. A gasket i t is provided to prevent moisture from entering the housing chamber, and also to prevent breakage of the ceramic as the various parts are drawn together.

A metal terminal member i I at the upper end of the insulator 5 is preferably provided with a flange portion i2, and a solderless connector i3 for electrically connecting the novel discharge device with power leads. rlihe iiange portion serves to provide an open spark-gap lli with the electrode member 9 This spark-gap provides a means for keeping the arrester normally nonconductive, thereby isolating the arcfextinguishing parts from leakage currents. The gap dimension may be varied to' accommodate any surges of enough magnitude to threaten injury to protected equipment.

An external spark-gap arrangement is shown here, but it is not intended to restrict the novel arc-extinguishing chamber, hereinafter described, from operating with an internal gap arrangement (not shown). y

The lower portion of the stud ilV is threaded to engage with an internally threaded opening of a metal upper electrode plug l5. This plug ,is

.threaded externally to engage with the internal threads of the tubular retainermember l5. The retainer member is preferablyof azmatcrial, such as horn ber, capable of emitting un-ionzedgases and vapors when subjected to high arcing temperatures. The retainer material is preferably resilient in nature in order that it will respond to internal pressures without dangerof shattering. The upper end of the retainer member i6 extends above the electrode plug l 5 to provide a chamber il for a purpose hereinafter described.

A reinforcing sleeve I3 is provided to strengthen the retainer tube to withstand any surge pressures that may be generated. sleeve aidsin reducing radio interference, lserving also to modify the electrostatic field existing within the arcing chamber, thus lowering spark,- over values.

The lower end or" the tubular-'retainer inem- In additiony the F ber i5 is threaded to engage with a fitting it, which tting concurrently acts as a closure for the arrester housing, a lower terminal member for connection with groiuid, and as a means for discharging expansion gases to the atmosphere. The latter function is accomplished by means oi a discharge port Eil, the internal opening of which acts to seat the lower electrode plug Ei, which plug is electrically connected with said fitting. This electrode plug is provided with a plurality of vent openings 22, and is more clearly shown in Fig. 6. The electrode plug also serves to support the arc-extinguishing medium which is hereinafter described. A solderless connector is provided for electrical connection with ground, and is shown herein as a simple bolt-washer assembly 23 engaging with a threaded opening in the tting I9.

It will be apparent that the various parts oi the assembly are compressibly held together by the engagement or" the fitting It and the tubular retainer member i6. A gasket `2li is provided to prevent breakage of the housing l as the parts are drawn together. The insulator 5 and arcing horn S are also clamped in place by the engagement of the fitting ES and the retainer member i5 through the stud t. lt will also be apparent that the internal parts are easily accessible by disengagement of the `fitting le kand retainer member i5.

This invention contemplates the use of a novel arc-extinguishir clearly disclosed cross-section by Fig. 2, and in detail by Figs. 3, e, and 5. The principle of using adjacent lateral are passages as disclosed in the copending Wood application, Serial No. 157,542, is germane to the present invention. To provide these lateral arcing passages in the novel structure, a series of telescoped or concentric horn nicer' tubular members is contemplated as the arceiitinguishing medium. The particular novelty of the present structure will become apparent as the description proceeds.

A ber rod 39 extends between the arcing electrode plugs i5 and 2 I, and is centrally positioned therebetween. This rod is centrally located Within a series of concentric or telescoped liber tubular members designated by the reierence characters 3i, 32 and 3S as clearly disclosed in Figs. 1, 2, 3 and 4. These members and the rod are composed of material such as horn ber, capable of emitting un-ionized gases and vapors when subjected to high temperature arcs.

Attention is invited to Figs. 3 and e. These ilgures clearly indicate the preferable arrangement of wall vent openings Sli, 35, and 35, and the notched portions 3l and 3S of representative alternate concentric tubular members 3i and These telscoped ber tubular members are provided wth the above referred to Vent openings in an alternate arrangement for adjacent concentric members. It is here to be noted that though Fig. 2 indicates a cross-like positioning of the openings and notches, this particular arrangement is not to be considered as limiting. 'Ene notching and opening arrangements are especially placed so that the series of tubes may be set on the rod concentrically in an indiscriminate fashion with no Wall openings lining up trans- Versen' between adjacent tubular members. En `Order to insure this, the openings are provided by boring straight through each or" the tubular members to provide damlrically opposed openings, as is clearly Vshown in Figs. 3 and d. The notched portions 3l and 38 are also placed in a diametrically opposed manner in wall surfaces 90 vfrom that of the wall openings. Thus, any gases created by an arc initiating from the upper electrode plug will necessarily be dispersed, .no matter the relatively confined lateral passageway taken by said arc. This dispersion oifers itself to rapid cooling of the expanding gases.

Though the space between adjacent tubes is relatively conned, it is understood that the tubes will be of a dimension that will permit movement about the center rod. Thus, it will be seen that no matter the manner of positioning the tubes in the arcing chamber it will be free to revolve about the rod without any of the vent openings lining up in a transverse manner thereby permitting maximum dispersion of the expanding gases.

Two sets of the series of telescoped tubes are shown in Fig. 1, and separated by a perforated fiber disk 40. A convenient method of perforating this disk is shown'in Fig. 5 which method of perforation permits a maximum amount of vent openings 4I, yet permitting the proper support surface for the upper series of telescoped tubes. It will be apparent that the fiber disk 4D is provided for supporting the sets of the telescoped concentric

tubular members

3 I, 32 and 33, and are also provided to prevent straight line arc and gas paths b etween electrode plugs I5 and 2| thus preventing arc path from concentrating on one series of telescoped tubes or one path only. Though two sets of the concentric tubular members 3|, 32 and 33 are shown for convenience reasons, a greater or lesser number of sets and separating disks 40 may be used according to the kva. rating of the associated electrical apparatus to be protected.

Corresponding tubular members in each of the two illustrated sets, as shown in Fig. l, have been designated by identical reference characters in that individual tubular members of a particular set are substantially identical to those of other' sets. Though three concentric tubular members are shown in each set in Figs. 1 and 2 it is understood that this is a preferable arrangement, and is not to be considered as limiting in any manner. However, it is to be noted that adjacent telescoped tubes are preferably provided with the alternate vent opening construction as shown in either Fig.

3 or Fig. 5 to permit maximum diffusion of genrelationship to erated gases no matter the axial one another.

The notched portions 3l and 3S are provided at both ends of each of the tubular members to permit the expanding gases to have access to the openings 4I of washer 4S and vent openings 22 of lower electrode plug 2 I. Though it is not particularly necessary to have these notches immediately adjacent to the lower surface of the upper electrode plug I5, they are provided in order that no particular attention need be paid to the manner of placing the tubes in the arcing chamber.

The operation of the novel discharge device is as follows: Any surge potentials of enough magnitude to threaten injury to the equipment to be protected will simultaneously spark across gap I4 and the spaced gap provided between arcing electrede plugs I5 and 2|. It is well known that this spark-over preferably travels a relatively confined and the shortest path between arcing electrode plugs. This relative confinement is provided by the passages between adjacent tubular members, or the rod and its adjacent tubular member shown herel as member 3l.

Immediately following this initial spark-over, the arcwhich follows acts upon the ber tubular members to produce copious quantities of unionized gases and vapors. Theseexpanding gases act to cool the arc and simultaneously force ionn ized gases through any of the vent openings in the walls and notches of the tubular members, and through the openings 4I of disk 40 to the next series of tubular members and out the ports 22 'of electrode plug 2| to the discharge port 28 of fitting I9. These expanding gases, in forcing out the ionized gases prevent power follow current from reaching ground. This 60 cycle arc is extinguished at the end of the rst half cycle oi current, at the instant the ground passes through zero. After this current interruption the novel discharge device is again in its non-operating condition ready for another surge.

It is apparent that effective arc extinction and expulsion may be accomplished with sets of concentric tubular members, said members not including the '

wall openings

34, 35 and or the notched

portions

31 and 33. However, as was heretofore suggested, this construction invites deleterious erosion of the wall surfaces of the concentric tubular members. This occurs from the rapid passage of generated gases within the initiating arc path between said members. Subsequent operations of the discharge device serves to enhance this eroding carvburization. It will readily be seen that all of the advantages of laterally adjacent arcing passages are incorporated in the novel discharge device by an effective arcextinguishing medium in combination with a novel means for increasing arc dispersing surfaces in order to materially reduce eroding carburization of said medium.

The described operation of the novel discharge device necessarily anticipates that the spark-over and subsequent arcing occur within the novel arc-extinguishing medium, without external flash-over to ground. This is assured by providing the chamber I'I in tubular retainer member I6 above the upper electrode plug l5, and the insulating washers 5U and 5I on the plugs I5 and 2|. Thus, the flash-over distance between the stud 4 and the reinforcing shield I8 may be kept greater than the spark-over distance between arcing electrode plugs I5 and 2|. This is done by varying the depth of the chamber Il according to the spark-over distance by the arcing plugs in such manner as to keep this flash-over distance a greater length. The washer El may also be varied in dimension to provide a greater flashover resistance between the upper edge of the reinforcing sleeve I8 and the lower edge of the plug I5. Both insulating washers 59 and 5i serve to concentrate the arc towards the center cf the arc-extinguishing medium rather than the outer edges close to the arrester housing .where flashover is likely to occur.

It will be apparent that a novel protecting discharge device has been disclosed that will provide a low spark-over and high surge capacity with a relatively long life. The beneficial prin ciple of providing lateral adjacent passages is maintained, yet provisions are made to disperse arc-extinguishing gases in a manner that will cause minimum erosion of the arc-extinguishing medium.

I claim:

l. In a discharge device for electric lines an insulating tube providing an arcing chamber closed at one end and open at the other end and two spaced electrode members, an arc-extinguishlng medium composed of material capable of emitting effective quantities of arc-extinguishing gases when subjectedto high temperature and contained within said tube, said medium comprising a rod-like member within the chamber and extending between and supported at either end by said electrode members, said medium further comprising a plurality of sets of telescoped tubular members within said chamber in unrestrained axial endwise relation to each other and radially spaced from said rod-like member, each member being independently freely movable transversely relative to the axis of said rod-like member within said chamber, one of said electrode members being exposed to said chamber at the closed end thereof and the other of said electrode members being disposed at the open end of said chamber and being apertured to discharge gases generated within said arcing chamber, the wall surfaces of said adjacent sets oi telescoped tubular members defining arcing passages disposed between said electrode members, and means spacing adjacent sets of tubular members axially relative to each other without interfering with transverse movement of said members and providing venting areas between the spaces within the adjacent members.

2. In a discharge device for electric device for electric lines an insulating tube closed at one end and open at theV other and two spaced electrode members, an arc-extinguishing medium composed of material capable of emitting effective quantities of arc-extinguishing gases when subjected to high temperature and contained within said tube, said medium comprising a rod-like member within the chamber and extending `between and supported at either end by said electrode members, said medium further comprising a plurality of sets of telescoped members within said chamber in unrestrained axial endwise relation to each other radially spaced from said rod-like member, each member being independently freely movable transversely relative to the axis of said rod-like member within -said chamber, one of said electrode members being exposed to said chamber at the closed end thereof and the other of said electrode members being disposed at the open end of said chamber and being apertured to discharge gases generated within said arcing chamber, said telescoped tubular members each being provided with a plurality of notched portions at each end and a plurality of wall vent openings, said notched portions and wall vent openings each arranged relative to the others to dispose. them in spaced circumferential and axial relationship in adjacent tubular members with said adjacent telescoped tubular members defining arcing passages disposed between said electrode members, and a vented disk of arc-extinguishing material, said disk supported by said rod-like member and separating said sets of tubular members.

3. In a discharge device for electric lines an insulating tube providing an arcing chamber, an electrode member in said tube providing a closure for one end of said tube, a reinforcing metallic sleeve for said insulating tube, said electrode member being disposed at a point within said tube spaced from said end of said insulating tube in order to provide an insulating chamber for preventing arc ash-over between said electrode member and said metallic reinforcing sleeve, a second electrode member oppositely disposed within said arcing chamber and being apertured to discharge gases generated within said' arcing chamber, and an arc-extinguishing medium of a material capable oi emititing eiective quantities of arc-'extinguishing gases when subjected to high temperature and contained within said arcing chamber, said medium comprising a rod=lilre member within the chamber and extending between and supported at either end by said electrode members, said medium further comprising a plurality of telescoped tubular members within said chamber in unrestrained axial endwise relation to each other and radially spaced from said rod-like member each member being independently freely movable transversely relative to the axis of said rod-like member within said chamber, said telescoped tu-bular members each being provided with a plurality of wall vent openings, said wall openings each arranged relative to the others to dispose them in spaced circumferential and axial relationship in adjacent tubular members, and a vented disk of arc-extinguishing material, said disk supported by said rod-like member and separating said sets of tubular members.

a. In an electrical discharge device an insulating tube providing an arcing chamber, an electrode member providing a closure for one end of said chamber, a metallic reinforcing sleeve for said insulating tube, said electrode member being disposed at a point within said tube spaced from said end of said insulating tube in order to provide an insulating chamber for preventing arc lashover between said electrode member and said metallic reinforcing sleeve, a second electrode member oppositely disposed within said arcing chamber and being apertured to discharge gases generated within said arcing chamber, an arc-extinguishing medium contained within said arcing chamber and comprising a rod-like member within the chamber and extending between and supported at either end by said electrode members, said medium further comprising a plurality of sets of telescoped tubular members within said chamber in unrestrained axial endwise relation to each other and radially spaced from said rod-like member, each member being independently freely movable transversely relative to the axis of said rod-like member within said chamber, said arc-extinguishing medium being composed of material capable of emitting eieetive quantities of arc-extinguishing gases when subjected to high temperature, said telescoped tubular members each being provided with a plurality of notched portions at each end thereof, said notched portions providing a means for ventilation between adjacent sets or said tubular members.

5. In a discharge device for electric lines an insulating tube providing an arcing chamber closed at one end and open at the other and two spaced electrode members, a metallic reinforcing sleeve ior said insulating tube, an arcextinguishing medium composed of a material capable of emitting eective quantities of arcextinguishing gases when subjected to high temperature and contained within said chamber, said medium comprising' a rod-like member within the chamber and extending between and supported at either end by said electrode members, said medium further comprising a plurality of sets of telescoped tubular members within said chamber in unrestrained axial endwise relation to each other and radially spaced from said rod-like member, each member being independently freely movable transversely relative to the axis of said rod-like member within said chamber, one of said electrode members being exposed to the closed end of said chamber and being disposed at a point Within said tube spaced from said end in order to provide an insulating chamber for preventing arcng Hash-over between said electrode member and said metallic reinforcing sleeve, the other of said electrode members being oppositely disposed at the open end of said chamber and being apertured to discharge gases generated within said arcing chamber, the wall surfaces of said adjacent sets of telescoped tubular members defining arcing passages disposed between said electrode members, said tubular members each being provided with a plurality of notched portions at either end and a plurality of wall vent openings, said notched portions and wall vent openings each being arranged relative to the others to dispose them in spaced circumferential and axial relationship in adjacent tubular members, and a vented disk of arc-extinguishing material, said disk being supported by said rod-like member` and separating adjacent sets of tubular members.

CLIFFORD' W. PETERSEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS