US2559426A - Arrester - Google Patents

Description

July 3, 1951 w. c. HA'ssELHoRN Erm. 2,559,426

Filed July 5l, 1948 @ff a 23153315 3 l JNVENToR: WalerClcweI/za BY aker aan fev l Patented July 3, 1951 ARRE STERy Walter C. Hasselhom and John S. Baker, Chicago, Ill., assignors to Cook Electric Company. Chicago, Ill., a corporation of Illinois Application July 31, 1948, Serial No. 431,748

6 Claims.

This invention relates to improvements in arresters, particularly for lines where relatively low voltage excess currents are to be guarded against, such as in telephone, communication and other similar lines.

In such systems, such protection is commonly sought by providinf. a short or narrow air gap between the electrodes of the arrester. But such small air gaps are prone to bridge or short-circuit or to become smaller, by roughness or points raised on the opposed faces of the electrodes by the action of the arcs thereacross or foreign matter lodging thereon, whereby their efficacy.

as arresters for giving the desired protection is impaired or destroyed.

An object of this invention is to overcome the difficulty by providing an arrester in which the electrodes may be more widely spaced, so that such bridging, short-circuiting or the like is not likely to occur but which gap will still break down and flash over at the low voltage excess currents to be guarded against, whereby continued protection may be afforded by the arrester.

A further object of the invention is the provision of an arrester in Which the spark gap space is filled with a gas having a lower break-down voltage than air, whereby the discharges may take place at a lower voltage of excess voltage current or for protecting against the same voltage values the spark gap may be made wider and thus eliminate short-circuiting of the electrodes by bridging points or the like.

A further object of the invention is the pro- -vision of an arrester in which the spark-gap space is filled with neon lgas and a small amount of argon, whereby discharges take place at lower voltages than if air alone filled the space.

Further 'advantages and objects severally are. to provide a multiple arrester bar having a plurality of alternate insulating and electrode washers or ring discs mounted on a bar forming a common electrode for the disc electrodes and a support for al1 the discs; to provide such an arrester which as a unit is coated with an enamel; to provide such an arrester in which the spark gaps are filled With a dielectric gas of higher conductivity than air; to provide such an arrester in which the spark gaps are connected together into a single recess which is filled with neon gas and a small amountA of argon to lower the voltage breakdown between electrodes, and to provide a simple arrester bar for a number of lines which will take up but little room, be inexpensive, con-v venient, and permit the use of wider spark gaps for low voltage excess current protection than heretofore.

. threaded onto said bar.

Further advantages and objects will appear from the description and claims to follow, in connection with the accompanying drawing, which discloses one form of the invention by way of example but not of limitation, and in which- Figure 1 is a side view of an arrester bar embodying the invention:

Fig. 2 is a cross section of the same on the line 2 2 of Fig. 1;

Fig. 3 is a similar view on the line 3-3 of Fig. l;

Fig. 4 is a section of one of the ring disc electrodes on the line 4 4 of Fig. 2;

Fig. 5 is a similar view of one of the insulating ring discs on the line 5-5 of Fig. 3; and

Fig. 6 isa longitudinal section of the bar at one end of the bar and at somewhat larger scale than Fig. 1.

Referring to these figures of the drawing. a plurality of metal electrode washers, rings, discs or plates IU alternating with suitable insulating washers, rings, discs or plates Il may be strung or mounted on a metal bar, rod or shaft I2 and suitably held together face to face on said bar, as by suitable nuts I3 at the ends of the group and The electrode washers I0 preferably may be recessed on one side, as at I4, Fig. 4, into which the adjacent insulating washer II tightly ts when the two are pressed together, as seen in Fig. 6. The inner periphery of. the insulating washer Il closely engages the bar I2 preferably at three places I5, as seen in Fig. 3. Its outer periphery is closely engaged by the peripheral flange i6 of the electrode disc or Washer I0, the result being that the electrode washer is rigidly held in definite relation laterally to the central bar I2.

This is important because the apertures in the electrode washers are made larger than the bar I2 and their inner peripherres Il constitute the sparking or arcing surfaces of these electrodes. The bar I2 constitutes the other and common electrode for all the individual electrodes I0. The spaces between these electrode washers and the bar form the spark gaps I8 of the arresters. It is important, therefore, that this spacing or the spark gaps be established and maintained accurately, and the structure described accomplishes the desired results.

Each electrode washer I0 is provided with two terminals I9 to enable the same to be connected in a line to be protected. The bar I2 is suitably grounded and ordinarily so through the framework of the support, to which it may be attached.

These electrode washers I0 of metal may be cheaply made by stamping the same with a circular peripheral fin, preferably substantially in the plane of the side of the washer opposite the flange I5 and of a depth equal to the length of the terminals I9 shown, and then cutting away parts of the nn to leave the integral terminals Il. This may all be done by simplestamping and punching operations. The faces of the electrode washers may also be provided with circular grooves 2| and 22 to be filled with insulating adhesive enamel, as hereinafter explained.

The insulating washers I I, except the end ones of the group, are preferably provided with communicating apertures between the spark gaps I8, preferably by inner peripheral cut-backs, notches or recesses 23, Fig. 3, of a suitable depth such as that of the spark gaps, so that all the spark gaps are joined together into va `continuous enclosed chamber. f

Provision for extracting the air from and iilling this chamber with gas is indicated in Fig. 6. One or both ends of the bar I2 may have a central bore 24 connected by a transverse hole or port 25 with the said recess. A tube 26 slidable in air-tight and gas-tight relation in said bore is adapted to receive a hose coupling or similar connection on its outer end from a vacuum pump or gasor air-pressure source, whereby in the position shown in Fig. 6, air or gas may be ex` hausted from or filled into the spark gap recess I8. At other times the tube 2B may be pushed or driven deeper into the bore 24, as indicated in dotted lines, which closes the port 25. A suitable plug may be driven into the outer end of tube 2S, if desired, to close the passage therethrough. To insure securing these washers I and I I strongly together and in airand gas-tight relation to each other and on the bar, it is preferred to coat the insulating washers with an insulating adhesive enamel, as by dipping them in the liquid material before assembly and compressing all the washers together on the bar by the end nuts I3, the grooves 2I and 22 being lled with the material squeezed therein or initially suppliedthereto. This coating is indicated in Fig. by the numeral 21.

When the parts are all assembled into an arrester bar as shown and described, the entire bar preferably is dipped into a bath of insulating adhesive enamel to receive a substantial coating 28 thereof, the ends of the bar and the projecting terminals I9 being suitably covered at the time to prevent being coated also, and the whole device so coated is then baked in the usual way of baking such enameled objects. This produces a strong, durable, sealed and enameled arrester bar.

As stated, it is preferred to make the spark gaps I8 between the electrode washers I0 and the bar I2 wider than the usual air gaps and to ll these gaps with a gas having a correspondingly lower breakdown voltage than air, whereby the same protection may be afforded against excess voltage cu'rrents on the lines as the usual air-gap arresters, but the gaps do not become bridged or short-circuited in use by the material of the electrodes due to the arcing.

It is found that neon gas having a small content of argon efliciently accomplishes the desired results, although any two gases may be used which when mixed together will cause an ionization of one by the other to lower its dielectric value. Neon gas with 0.1% to 1% of argon is found to give satisfactory operation. Accordingly, the air is rst exhausted from the sparkgap recess in the arrester bar through the medium of tube or tubes 26. Since argon tends to 4 be absorbed by the walls of the chamber, it is preferred next to fill the spark-gap recess with argon to saturate the walls thereof with it. After this the recess or chamber is lled with neon gas having a small amount of argon in it, asV

described. The end plugs 26 are then driven into place to close the ports 25 and the arrester bars are ready for installation and use. With the spark-gap recess so iilled, the arrester has a breakdown voltage less than ii. illled with air or neon alone.

The arrester bars thus constructed may be conveniently mounted in a bar or strip 29, the ends 30 and 3I of which extend at an angle and receive the threaded ends of the bar I2. A nut 32 on each threaded end then tightly clamps the arrester bar in place in the mounting bar. As shown at the right in Fig. 1,'a pair of arrester lbars may be secured in each mounting bar, in

which case the two sides of a line may include the pair opposite each other on the two arrester bars. The mounting bar 29,may form part ofthe supporting rack at the plant or be suitably attached thereto, `and in any case is suitably grounded.

Without further elaboration, the foregoing will so fully explain the gist of the invention that others may, by applying current knowledge, readbar at their inner peripheries and holding said electrode discs with their inner peripheriea spaced from and in spark gap relation to said bar, line terminals connected with said electrode discs, the electrode discs forming individual arrester electrodes for the` lines to be protected and the bar forming a common electrode for all the arresters, portions of said inner peripheries adjacent the bar being removed in the insulating discs except from the end discs, the said bar having a longitudinal bore at an end leading to the surface thereof between the end discs of the arrester bar.

2. A lighting arrester comprising a central mounting rod forming a grounded electrode and having its ends threaded, a plurality of alternately arranged line electrodes and insulation washers on said rod, said washers being slidably disposed upon said rod and having shoulders sup-v porting said line electrodes spaced from said rod to provide a plurality of spark gaps between the line electrodes and said rod, said washers having spaced openings therein to form with said spark gaps a closed gas-filled chamber, and lock nuts at said threaded ends to hold said line electrodes and said washers together in gas-tight relation.

3. A lighting arrester comprising a central mounting rod forming a grounded electrode, a plurality of alternately arranged line electrodes and insulation washers on said rod, said washers being slidably disposed upon said rod and having shoulders supporting said line electrodes spaced from said rod to provide a plurality of spark gaps between the line electrodes and said rod, said washers having spaced openings therein to form with said spark gaps a closed gas-filled chamber, and means at the ends of said rod to hold said line electrodes and said washers together in gastight relation.

4. A lighting arrester comprising a central mounting rod forming a grounded electrode, a r

plurality of alternately arranged line electrodes and insulators on said rod, said line electrodes having peripheral flanges closely engaging the outer peripheries of said insulators, said insulators resting upon said rod for holding said line electrodes spaced from said rod to provide a plurality of spark gaps between the line electrodes and said rod, said insulators having openings therein to form with said spark gaps a closed gasillled chamber, and means at the end line electrodes and insulators for holding all vof said line electrodes and insulators upon said rod in operating relation with respect to each other.

5. A lighting arrester comprising a central mounting rod forming a grounded electrode, a plurality of alternately arranged line electrodes and insulators on said rod, said insulators resting upon said rod and having shoulders supporting said line electrodes in spaced relation to said rod to provide a plurality of spark gaps between the line electrodes and said rod, said insulators having openings therein to form with said spark gaps a closed gas-iilled chamber, and means disposed adjacent the end line electrodes and insulators for holding all of said line electrodes and insulators upon said rod in operating relation with respect to each other.

6. A lighting arrester comprising a -central mounting rod forming a grounded electrode, a plurality 'of alternately arranged line electrodes and insulators on said rod disposed in recessed relation with respect to each other, said insulators resting upon said rod and supporting said line electrodes' in spaced relation to said rod `to provide a plurality of spark gaps between theV electrodes and said rod, said insulators having openings therein to form with said spark gaps a closed gas-filled chamber, and means at the ends of said rod for holding all of said line electrodes and insulators upon said rod in operating relation with respect to each other.

WALTER C. HASSELHORN. JOHN S. BAKER.

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

UNITED STATES PATENTS Number Name Date- 1,017,649 Chapman Feb. 20, 1912 1,249,429 Lewis Dec. 11, 1917 1,511,744 Metzger Oct. 14, 1924 1,603,279 Gray Oct. 19, 1926 1,818,184 Worket al Aug. 11, 1931 2,370,082 Slepian Feb. 20, 1945 FOREIGN PATENTS Number Y Country Date 227,832 Great Britain Jan. 12, 1925 353,924

Great Britain July 29, 1931

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