US1947076A - Lightning arrester - Google Patents

Description

Feb. 13, 1934. R. v. BECKETT n AL 1,947,076

LIGHTNING ARRESTER Filed May 28, 1930 INVENTORS Eu5se// KEecAe/l 000 Ch ar/esL .Jbnes.

A'TToRNEY Patented Feb. 13, 1934 UNITED STATES uon'rmo saaEs'raa Russell V. Beckett and Charles L. Jones, Pittsburgh, Pa asslgnors to Westinghouse Electric and Manufacturing Company, a corporation of Pennsylvania Application May 28, 1930.

19 Claims.

This invention relates to lightning arresters and more particularly to casings for such devices. Prior to our invention, various expedients have been resorted to, to clear a lightning arrester from I the line upon failure of the arrester to interrupt the follow current on return of line voltage to normal. These previous expedients have included cementing in a drop-out bottom or employing a fusible bottom plate or a ceramic ring having a thin portion adapted to crack upon continued application of heat.

We have provided a novel and simple construction which serves the same purpose, and is, in many respects superior to the preceding construcll tions, our novel construction comprising a main casing member having a metal drop-out bottom soldered or brazed directly to the main casing member. The joint is made of material having such fusing point that the heating of the device it during normal operation will not affect the union but, upon the continuation of the heating for an abnormal period, the soldering-or brazing material would be fused, thus permitting the drop-out member to function.

It is an object of our invention to provide an improved lightning arrester.

It is a further object of our invention to provide an improved casing or casing-assembly for a lightning arrester.

It is a still further object of our invention to provide an improved drop-out bottom or closure for a lightning arrester casing.

Other objects and advantages will be apparent from the following detailed description, taken in conjunction with ,the accompanying drawing, in.

which s Figure 1 is a sectional elevational view of our improved lightning arrester,

Fig. 2 is a fragmentary detail view showing a modification of the casing,

Fig. 3 is a similar detail view showing a further modification, and

Figs. 4, 5 and 6 are similar views showing still Serial No. 456,347

The main casing member 1 will usually be counterbored near the lower end to provide a shoulder 15 adjacent to the chamber or passage 2 containing the active elements 5 and 6. The counterbore, in. addition to providing a shoulder 00 adjacent to the element-receiving passage or chamber 2, also constitutes the bottom portion of a skirt 16 to exclude the weather from the chamber 2 in the casing. The external portion of the skirt 16 is usually provided with a seat for 06 a supporting clamp, such as a bracket 17.

The outer face of the shoulder is provided with a solder-receiving glaze 20 which will usually be metallic in nature.

Our novel closure plate or drop-out member 21, provided with a ground conductor 23, is integrally connected to the solder-receiving glaze 20 by a soldered or brazed joint 24. The closure plate 21 is provided with an offset portion 25, of substantially the same diameter as that of 15 the mouth of the chamber 2, to assist in centering the closure plate during the assembly of the arrester. In operation, that offset portion 25 provides a flexible section so that expansion or contraction of the closure plate, due to variations in temperature, will be absorbed by the flexible portion, thus relieving the soldered joint 24 of stresses resulting from such contraction or expansion.

It is frequently desirable to place under the drop-out member 21 an insulating shield, such as a ceramic disc 30 (omitted from Figs. 2 to 6 for purpose of clearness) The shield is preferably perforated to permit the passage of the ground conductor 23. After the assembly of the drop-out member or cover plate 21 and the final soldering of the same to the casing, the shield is secured to the drop-out member by any suitable cement. This shield not only insulates the closure to prevent accidental contact with the same, but also excludes the ambient air from contact with the closure so that the heat capacity of the closure .will be substantially constant at all times.

A modification permitting ease of assembly, together with a reduction of rejections of flnished casings, consists in making the mouth of the element-receiving chamber 2 out of a separate ring-like piece or ceramic casing-element 35 cemented in place. The ring-like piece may be provided in several different forms, as shown in Figs. 2 and 3, to facilitate ease of positioning the ring.

When the separable ring is employed, the solder-receiving glaze 20 is applied to the outer end 110 of the ring, so that rejections for improper firing of the glaze will apply only to the separate ring-like members and not to an entire casing. Furthermore, the closure plates 21 may be soldered to the rings 35 and tested prior to assembly in the completed casings.

It is thus apparent that we provide an insulating housing or casing-assembly which may consist either of a single element such as the main casing member 1 of Fig. 1, or of two elements comprising a main casing member and a separate ring-like piece 35 as in the other figures of the drawing.

In many locations where these lightning arresters are placed, it is not permissible or desirable to allow the elements 5 and 6 to drop from the casing when the units are cleared from the line. It is necessary, therefore, to provide arresters with means for retaining the elements 5 and 6 in the casing when the drop-out mem bers 21 are released. This may be done by providing the ring-like mouth-piece 35 of the chamher 2 with a restricted portion as shown in Fig. 4, or as shown in Figs. 5 and 6, the closure plate itself may be made of two or more portions 21' and 21".

In the last-mentioned case, as shown in Figs. 5 and 6, the closure plate consists of an outer ring-like plate 21' soldered to the shoulder at the mouth of the chamber, and a central portion 21" soldered to the ring-like member. This central portion 21" may be free of the arrester elements, as shown in Fig. 5, or may be offset to carry the entire weight of the elements, as shown in Fig. 6.

Usually, it will be found that the central portion 21" will be more readily disengaged than the external ring-like portion 21', but, if necessary, a softer or easier-melting solder may be employed to make the connection between the central and external portions 21" and 21 of the closure plate.

The operation of our device is as follows: In normal operation, the abnormal voltage will be discharged through the lightning-arrester element until the abnormal voltage has been dissipated, at which time the arrester will interrupt the current before any appreciable amount of heating has occurred in the elements. However, if, for some reason, the arrester should fail to interrupt the current, due, for example, to a high-voltage conductor falling across the line, the continuous passage of current through the valve elements 6 will cause excessive heating of these elements. This heat will, in turn, be transmitted to the closure plate 21 until the plate is sufllciently heated to fuse the solder seal. At this time, the closure plate 21 will drop away from the casing 1 and allow the elements to be discharged from the casing (in the forms shown in Figs. 1 to 3), thus effectively clearing the arrester from the line. In the modifications shown in Figs. 4 to 6, the drop-out member alone will be expelled from the casing, leaving the elements 5 and 6 still in the casing member 1, but as the ground conductor 23 has been removed, the arrester will be effectively cleared from the line.

We do not desire to restrict ourselves to the specific embodiments of our invention herein shown and described, since it is evident that our arrester casing may be changed and modified without departing from the spirit and scope of our invention as defined in the appended claims.

We claim as our invention:

1. A lightning arrester comprising an insulating casing-assembly having a chamber therein, lightning-arrester means in said chamber, a solder-receiving glaze around the mouth of the chamber, a two-part closure element for the mouth of the chamber, the outer part of said closure element comprising a ring having a central opening of less size than the arrester elements, said ring being integrally secured to said glaze, the central part of said closure comprising a plate integrally united to said ring, a conductor integrally connected to the central portion of said closure, means for preventing rupture of the union between the closure and the casing-assembly because of expansion or contraction of the closure, the relation of the parts being such that the central portion of said closure is released upon coontinued current-flow through the arrester means.

2. A lightning arrester comprising an insulat ing casing-assembly having a chamber therein, lightning-arrester means in said chamber, a solder-receiving glaze about the mouth of said chamber, a closure composed of a plurality of parts soldered to said glaze, a conductor secured to said closure, said parts being in good thermal contact for detaching at least a portion of said closure upon continued current-flow through the arrester means.

3. A lightning arrester comprising an insulating casing-assembly having a chamber therein, lightning-arrester means in said chamber, a solder-receiving glaze about the mouth of said chamber, a closure composed of a plurality of parts soldered to said glaze, a conductor secured to said closure, said parts being so arranged as to detach at least a portion of said closure upon continued current-flow through the arrester means, and means for retaining said arrester elements in said casing-assembly after detachment of a portion of said closure.

4. A lightning arrester comprising a main casing member of insulating material having an opening therein, lightning-arrester means in said opening, a ring of insulating material secured in said main casing member and forming the mouth of said opening, a glaze on the outer end of said ring capable of receiving solder, a metal closure plate integrally united to said glaze, said plate comprising an outer ring-like portion having an opening therein of less diameter than the diameter of the arrester means, and a central portion integrally united to said ring-like portion, a conductor soldered to said central portion, means for preventing rupture of the union between the plate and the ring because of expansion or contraction of the plate, said central portion being separated from said ring-like portion upon continued current-flow in said arrester means.

5. A lightning-arrester housing comprsing a casing-assembly of insulating and moisture-proof material having an opening for the reception of the arrester means, a closure for said opening, means for positioning said closure in relation to said opening, a conductor attached to said closure, and means for connecting said closure to said casing assembly, and operable, on continued current-flow through said elements, to disconnect said closure from said casing.

6. A lightning-arrester housing comprising a casing-assembly of insulating and moisture-proof material having an opening for the reception of the arrester elements, a ring of metal glaze adjacent to one end of said opening, a metal closure integrally united to said glaze, a conduc- III tor connected to said closure, and a perforated insulating shield surrounding said conductor and secured to said closure, and operable on continued current-flow through said elements, to remove said conductor from conducting relation to said elements.

7. A lightning-arrester housing comprising a ceramic casing-assembly having a cylindrical opening therein, the surface at one end of said opening being adapted to receive solder, a closure soldered to said surface, means for preventing rupture of said solder by expansion or contraction of the closure, and a conductor soldered to said closure, the arrangement being such that said closure is released upon continued passage of current through the lightning arrester.

8. A lightning-arrester housing comprising a ceramic casing-assembly having a cylindrical opening therein, an insert secured in said casingassembly, said insert forming a shoulder at one end of the opening, one surface of said insert being prepared to receive solder, and a closure member soldered to said insert.

9. A lightning-arrester casing-assembly comprising an insulating body having a chamber therein, a weather-proof cover at the top of said body, the lower end of said chamber comprising a separate ring cemented into said body, a metal glaze applied to the outer end of said ring, and a closure plate soldered to said metal glaze.

10. A lightning-arrester casing-assembly comprising an insulating body having a chamber therein, a weather-proof cover at the top of said body, the lower end of said chamber comprising a separate ring cemented into said body, a metal glaze applied to the outer end of said ring, a

closure plate soldered to said metal glaze, and means for preventing rupture of the soldered joint by expansion or contraction of the closure plate.

11. A lightning-arrester casing-assembly comprising an insulating body having a chamber therein, a weather-proof cover at the top of said body, the bottom of said chamber comprising a separate ring cemented into said body, a metal glaze applied to the outer end of said ring, a closure plate soldered to said metal glaze, means for preventing rupture of the soldered joint by expansion or contraction of the closure plate, a ground lead attached to said closure plate, the arrangement being such that said lead is disconnected upon excessive heating within said casing-assembly. I

12. A casing-assembly for a lightning arrester comprising a ceramic body having an opening adapted to receive the active means of a lightning arrester, one end of said opening being enlarged, a ceramic ring in said enlarged end having an opening substantially equal in diameter to the diameter of the opening in the body, a metal glaze on one end of said ceramic ring, and a metal closure plate soldered to said metal glaze.

13. A lightning arrester comprising a ceramic casing-assembly having an opening adapted to receive the active lightning arrester means, a conducting member secured to the top of the casing and adapted to be connected to the protected circuit, a weather-proof cover above the conducting member, lightning-arrester means asenabled in said opening and in contact with said conducting element, a metal glaze applied to a portion or the surface of the casing-assembly adjacent to the lower end of said opening. and a metalclosureplatesolderedtosaidglale.

ltAcaaing-aeeembiyforalightningarreeter comprising a ceramic shell having an opening therein adapted to receive lightning-arrester means, a metallized surface at one end of said opening, a metallic closure plate soldered to said surface, said plate having means for attaching a conductor thereto, and a shield having an opening in register with said conductor attaching means.

15. A lightning arrester characterized by an insulating housing and a two-part metal closure member on its lower end, said closure member comprising a central portion and an overlapping annular peripheral portion soldered together, with the rim of the central portion underlying the annular portion, 'and means for supporting the annular portion from the housing.

16. A lightning arrester comprising an insulating housing having at least one open end, lightning-arrester means therein, a metal closuremeans for one open end of said housing, said closureameans being joined with a metal-toinsulator joint to the surface of said housing, said metal closure-means having a cup-shaped protuberance extending inwardly within said open end of said housing, and a terminal lead connected to said metal closure-means within said cup-shaped protuberance.

1'7. A lightning arrester comprising an insulating housing having an open bottom end, lightningarrester means'therein, a metal closure-means I.

for the open bottom end of said housing, said closure-means being joined with a separable metal-to-insulator joint to the mouth of the opening of said housing, said metal closure-means having a cup-shaped protuberance extending inwardly within said open end of said housing, and a terminal lead connected to said metal closure-means within said cup-shaped protuberance.

18. A lightning arrester comprising an insu- 5.".

lating housing having an opening therein, lightning-arrester means in said opening, the bottom end of said insulating housing, surrounding said opening, having a surface-portion prepared to receive solder, a metal closure-means secured,

lating body having an opening therein, lightningarrester means in said opening, the bottom end of said opening being enlarged, an insulating ring secured in said enlarged end and having an opening substantially equal in size to said body opening, means for providing a retaining flange on the bottom of said ring, said flange having a smaller opening than said body, said flange having a bottom surface-portion prepared to receive solder, a metal closure-means secured. with a solder of low melting point, to said surface-portion, whereby said metal closure-means will become detached upon prolonged discharge of the arrester, said metal closure-means having a cup-shaped protuberance extending inwardly within said smaller opening and a terminal lead connected to said metal closure-means within said cup-shaped protuberance.

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