US2973448A - Lightning arrester and housing therefor - Google Patents

Description

A. G. 'YOST mam-um; ARRES'I'ER AND nousmc THEREFOR Feb. 28, 1961 Filed Sept 23, 1957 2 Sheets-Sheet 1 Feb. 28, 1961 YOST 2,973,448

LIGHTNING mans-rm m) novsmc Tl-IEREFOR Filed Sept. 25, 1957 2 Sheets-Sheet 2 Fig. 2

'n 83 84 HT 1 as a2 8 as mmvrox Arnold G.Yosf

it 121 UM ATTORN EY United States Patent O ARRESTER AND HOUSING A LIGHTNING THEREFOR Arnold G. Yost,Barberton, ohm, assignor m The Ohio Brass Company, Mansfield, Ohio,a corporation of New le'r'sey .1. V

a This invention relates to lightning arresters and protective devices and more particularly to lightning arresters for use in locations wherein the arrester housing is subject to atmospheric contamination.

It is known in the art pertaining to lightning arresters that, where the arrester is exposed to airborn contaminants, multiple unit arresters have substantial limitations. This is due to the fact that the multiple unit arrester is required to divide the impressed voltages and over-volt- 'agesf' substantially. equally among the several units of the arresters in order to utilize'the interrupting ability of which the arresters are capable under normal operating conditions. In such arresters, if one or more of the arrester housings becomes contaminated to such an extent that a finitejconduction current flows between the end terminals. of an arrester unit, the voltage division among the arrester units is upset, so that greater voltages are concentrated across. some of the units than across others of the units. Consequently,- the arrester units carrying the excess voltages will arc-overat relatively lower total impressed voltages ancl the interrupting ability of the arrester 'group is effectively reduced.

" One solution to this problem is set forth in United States Patent 2,881,362, issuedfApril 7, 1959, to J. W. K ,wherein non-linear grading resistors are connected between the terminals of the several arrester units of a multipleunit arrester. As described in that application, theco'ntamination of the housing of one of the arrester units'producessuch an increase in the grading current of theremaining arrmter units, because of the non-linear characteristics of the grading resistors, that the voltage division between the arrester units is maintained within much closer limits thanl would otherwise be the case. However, .in locations in whichlhigh levels of contamination'jprevail, erratic arrester'operation is possible, even with lightning arresters incorporating the design and construction of the subject patent. r

i" One'desirable solution of the problem would result, of course, if it were poss'ible to construct a lightning arrester having a single piece housing of such length that all of the necessary arrester elements could be encompassed ina singlecolumn extending between the end terminals of the arrester; there would thus be no exposed intermediate terminal members and no possibility of a voltage-divisionupsetting leakage current flow along the exterior of the housing. .Such arrangements have not heretofore been considered feasible because of the length of housing required to providean effective insulation at the relatively high operating voltages at which such arresters are used, and because of the impracticability of constructing a single unitary ceramic body of suchlengths.

According to'the present invention, I have conceived and devised a new lightning arrester which avoids the undesirable results referred to above. Moreover, the new arrester achieves all the advantages that would result from the use of a unitary ceramic housing.

L'Ifhe new arrester, as set forth and described herein, "embodies amulti-part housing such that the column of 2,973,448 Patented Feb. 28, 1961 arrester elements is connected only to the end terminals of the arrester. I am able to accomplish such an arrangement by utilizing a housing formed of two or more tuba lar ceramic members which are held by a multiple joint including an adhesive bond between abutting ends of the members and a surrounding mechanical connection cornpressively holding the ceramic members in abutting relationship. The adhesive bond unites and holds the ceramic members or the housing with sutficient strength to produce a strong unitary housing while providing a hermetic seal for the interior of the housing. The mechanical connection comprises two circumferential flanges which bear against outwardly protruding ridges formed circumferentially about the abutting extremities of the members and serve to accommodate any abnormal cantilever stresses such as might result during shipment, or other handling of the arrester. cial design and construction and function to protect the adhesive bond from atmospheric effects and, additionally, to prevent the accumulation of moisture at the junction of the two ceramic members.

I Accordingly, the principal object of the invention is to provide a high tension lightning arrester for use in air contaminated operating locations. Another principal object of the invention is to construct a ceramic insulating body of greater length and cantilever strength and which will function electrically as a single ceramic piece. Still another object of the invention is to provide an improved lightning arrester of increased capabilities as compared with the practices known in the art prior to this time.

A particular object of the invention is to unite tubular ceramic bodies.

The invention together with further features, objects, and advantages will be more clearly understood by referring to the following detailed specification and claims taken in connection with the appended drawings, in which Fig. l is a vertical sectional view of a lightning arrester embodying the invention;

Fig. 2 is an external view of the housing showing the flanged connection thereof; Fig. 3 is a vertical sectional view of an alternate em bodiment of the joint of the invention; and

Fig. 4 is an external view of the arrangement of Fig. -31.

As shown in the drawing, the lightning arrester 10 of the invention comprises a ceramic housing 11 having atop end fitting 12, a bottom end fitting 13, and a stack 14 of arrester elements. The housing 11 comprises two tubular ceramic parts 15 and 16 having interior openings 11 and 18 for accommodating the arrester elements and exterior skirts 19 and 20 for increasing the electrical leakage distance along the exterior of the housing. The two ceramic parts 15 and 16 are connected at the central part of the arrester by means of a joint, designated generally at 21, in two functional parts as hereinafter described.

Theceramic members 15 and 16 are formed with the adjacent end parts 22 and 23 radially enlarged so that the shoulder portions 24 and 25 project outwardly from the exterior of the longitudinal wall of the member. The two ceramic members 15 and 16 are joined along the end parts 22 and 23 by means of an adhesive bond 28 as hereinafter set forth. The end surfaces 26 and 27 are conformed by grinding or other suitable shaping processes to produce a close fitting of the surfaces and thereby increase the strength of the bond. The increased radial extent of the end surfaces 24 and 25, of course, produces an increase in the strength of the bond formed between the members.

The two ceramic parts 15 and 16 are held together by a mechanical connection including the flanges 29 and 30 which supplements the adhesive bond between'the end surfaces of the members as hereinafter described The flanges are of spe-' The. two. flanges 29 and 30 surround the ceramic members 15 and 16 at the adjacent extremities of the members and are Securely attached to the shoulder portions 14. and 25 of. the: members; by means ofieement-itous bonds 3k and; 3-2; "The bonds 31 and; 32 areiormed; by filling the: space between the; interiors of the flanges and the exteriors of the shouderswith suitable. knownbond;- ing materials such as- Portland; cement. -Additionally, the shoulder portions are formed; on the exterior thereof withsandedsurfaces 33' and 34' in. a manner well known in the art, e.g-,,jas. taught in- U.S, Patent 2,250,044 dated; July 22, 194- 1, and; Patent 2,287,976. dated June 30;. 1942. The spacing; between the .exteriorof: the sanded parts of the ceramic member; and interiors; of the flanges may be in the order of toof an inch for diameters in, the: order of 8 inches.. The flanges 29 and 30 are compressively secured-each totheother by means of cap screws.

The end fittings 12 and.-1 3' are of the; same constructon. and. may be described with reference to the top end fitting 12. That. fitting; comprises an annular casting 35 having an inwardly directed part 36, a longitudinally directed side wall 37 extending; downward along and spaced from the end part 38' of the housing member 15, andv mounting supports 39 The fitting is secured to the housing by means of a cementitous bond 40 which is applied between the. side wall 37 of the casting and a sanded surface 41 on-the exterior of the end part 38 of the housing, as heretofore described in. connection with the joint 21.

The interior of the housing is closed. by a plate 42 which is secured to the inwardly directed part 36 of the end. casting 35 and by a sealing cap 43- and a gasket 44. The cap; 4 3' and gasket 44" are compressively held against the end surfaces of the housing part 15 by a support ring 45, a spring 46, and a spring holder 47. The interior of the arrester is thus closed to the outside atmosphere and may be filled with an inert gas.

, The stack '14 of arrester elements includes aplurality of; valve. blocks 50 to 58 inclusive, and interposed seriesconnected arc gaps 59 to 64 inclusive. The valve blocks and arc gaps are supported by a plurality of annular ceramic members 65 which have flat metallic plates 66 carried on the opposite sides of the central part of the insulating member to interconnect the valve blocks and are gaps and to. provide grading capacitors, as is known in theart The entire arrangement of. valve blocks,: are gaps, insulating; members, and capacitor plates is held in stacked relationship between the end fittings lz and 13 by springs 67 and 68 and 69. The electrically endmost arrester e1ernen'ts, e.g., valve block 50 and. are gap 64,v are connected to the end fittings 12 and 13 by means of the spring 68 and metallic spacer 7t and spring 69- and metallic spacers 71 and 72 and associated plates, 66 respectively. The. end fittings 12 and 13 thus serve. not only. as closures for the housing and to mechanically support and retain the arrester elements, but alsoas electrical terminals for the arrester.

, vThe adhesive bond 28 of the joint 21. functions to constitute a hermetic. seal between. the ceramic members 15 and; 16, as well as holding the members together, and is; relieved of excessive stresses by the flanges 29 and: 30; and the connecting studs. The flanges are eifective upon the imposition of large cantilever stresses such as might be encountered in shipment or installation of the arrester. Moreover, the construction is such that if; the adhesive bond 28 does fail, thelayer of adhesive constitutes a gasket between the end surfaces 26 and 27 effective to maintain the hermetic seal. Thus, the condition of the interior of the arrester is maintained. even upon failure of the adhesive bond.

The construction of theflanges 29 and 30 is suchv that in; addition to their function as load carrying members they: shelter the. adhesive jpint while,- providing, suflicient 4 ventilation around the outside of the joint to prevent accumulation of moisture on or adjacent to the joint. Thus, the space 73 between the flanges 29 and 30 is sheltered by the downwardly depending skirt 74 about the peripheral extremity of the flange 30. Additionally, the upper surface 75 of the; flange 31 has a downwardly rounded upper surface so as to avoid any accumulation of condensed moisture.

The adhesive bond may advantageously be formed of any of severalknown high polymer adhesives such as, for example, the epoxy-resin, polyester resin, or polyurethane resin adhesives. A satisfatcory epoxy-resin adhesive is that known as Houghton Laboratorys No. 2545-112 with X-type hardener; The resin may be cured at 250 F. for a period. of about two hours, or at room temperature for about four to five days. The room temperature curing is desirable principally in the case of very large housingpartsr I In the. embodiment of the. invention shown. in Fig, 3, the abutting ends ofv the two.- ceramic members 77 and 78 are formed with shouldersv 79 and 80v which have load bearing surfaces in. the longitudinal directions of the housing. The mechanical connector 82 comprises an upper flange. 83 which extends. about the. body of the ceramic member and is arranged to bear upon the shoulder 79 through a gasket 84. Two cooperating lower flanges 85 and 86 bear upon the shoulder 80 of the lower ceramic. member andQare drawn toward the upper flange 83, by means of set. screws 87 to exert a compressive force upon the. shoulders 79 and 80 tending to hold. themembers77 and 78 together.

The: abutting ends of the ceramic members 77. and 78 are joined byan adhesive. bond 81 in the same'manner as the. bond 28 of Figs. 1 and 2, and the end' surfaces ofv the ceramic member are, of course, ground or otherwise closely fitted to obtain a maximum utilization of the binding properties of. the adhesive as well as to. insure the necessary hermetic seal between the parts.

The upper flange 83 has a downwardly and sidewardly projecting skirt-like portion 88 which serves to shelter the adhesive bond as well as provide a shoulder 89 for the lower flanges 85'. and 86. However, sincev the engage-'- ment of the lower flanges with the shoulder 89 would otherwise. completely enclose the space 90 within the flanges, the lower flanges are. formed in two parts with the adjacent. ends spaced apart as indicated at 91 to prevent any accumulation of moisture in the space 90. The lower flange may, of course, be formed in several pieces or as a single piece with suitable openings for draining the condensed'moisture.

' The upper flange 83 may constitute two interlocked metallic piecesfor use where. the exterior skirts. of the housing. prevent assembly from the opposite end of' the housing member.

It is to be understood that theforegoing description isnot. intended to restrict the scope. of the invention and that various rearrangements of the parts and modifications of. the design may be resorted to. The following claims are directed' to combinations of, elements which embodythe invention or inventions of this application.

I claim:

1. A lightning arrester of the type having a plurality of serially connected arc gaps comprising an elongated ceramic housing having a central opening therein extending longitudinally through. the housing and a metallic end fitting. at each end of the housing, the said. end fittings enclosing the interior of the housing and constituting base members for supporting the housing, a plurality of lightning arrester elements within the housing between the end fittings, electrical connecting means for the said arrester elements and spring means for maintaining the said arrester elements in the said stack and; means connecting only the end elements. of the said'stack. offarrester elementsto the said end. fittings, the. said. housing comprising at least twotubular. ceramic porcelain members with adjacent ends thereof in opposed aligned relationship, a radially enlarged portion at the adjacent end of each of the ceramic members to provide a radially enlargedarea of end surface and a radially pro jecting shoulder on the exterior of the member, metallic flange means for each of the ceramic members,means for transmitting longitudinal forces between the flange means and the ceramic members, means compressively connecting the two-flange means, and a hardened body of resin adhesive between the members bonded to the end surfaces thereof for sealing the interior of the housing and maintaining the'electrical insulating strength of thehousing within the two flange means.

2. The invention in accordance with claim 1 in which the flange means, in each instance, constitutes an annular metallic piece having a longitudinally extending part spaced from the housing and the shoulder and a cementitous bond between the flange member and the shoulder.

3. The invention in accordance withclaim 1 in which the flange means for an upper one of the said two ceramic members comprises an annular piece having the interior portion projecting inwardly to bear upon the shoulder of the ceramic piece and an outwardly depending skirt-like portion and the flange means for a lower one of the said two ceramic pieces comprising an annular member bearing upon the shoulder of the second ceramic piece and pivoted upon a shoulder within and above the lower extremity of the skirt of the first flange member.

4. A lightning arrester of the type having a plurality of serially connected arc gaps comprising an elongated ceramic housing having a central longitudinal opening extending throughout the length thereof, and a metallic end fitting at each end of the housing, means securing the end fittings to the housing and means sealing the interior thereof, the said end fittings constituting base members for supporting the housing and electrical terminals for the arrester, a plurality of lightning arrester elements arranged in a stack within the housing between the end fittings, spring means for maintaining the said arrester elements in the said stack and in electrically contacting relationship, and conductive means connecting only the end elements of the said stack of elements and the said end fittings, the said housing comprising at least two tubular ceramic porcelain members with abutting end surfaces, a solid body of hardened resin adhesive between the said end surfaces of the members, a sanded surface peripherally about the exterior of each of the ceramic members adjacent the abutting end thereof, a metallic flange about the abutting end of each of the ceramic members and a cementitious bond between the flange and the sanded surface of the ceramic member, and clamp means compressively connecting the flanges, the said housing constituting a substantially continuous insulating wall between the end fittings to constitute a hermetically sealed and electrically insulated interior for the arrester.

5. A composite ceramic housing for electrical ap paratus comprising two tubular ceramic members having adjacent end parts with closely fitted end surfaces, a radially projecting shoulder on the exterior of each member, metallic flange means for each of the ceramic members at the adjacent end parts thereof, means for transmitting longitudinal forces between the flange means and the ceramic members and means compressively connecting the two flange means, and a hard body of electrical insulating material between the ends of the said ceramic members adhering to the end surfaces thereof and uniting the members to seal the interior of the housing and maintain the electrical insulating strength thereof.

6. A composite ceramic housing for electrical apparatus comprising two tubular ceramic members having abutting end parts with closely fitted adjoining end surfaces and a central opening therein extending longitudinally through the members, a hardenedlbody of resin adhesive between the said adjoining end surfaces bonded to and uniting the ceramic members, a sanded surface peripherally about the exterior of each of the ceramic members adjacent the abutting end thereof, a metallic flange about the abutting end of each of the ceramic members, a cementitous body between each flange and the associated sanded surface for securing the flange to the ceramic part, clamp means compressively connecting the two flanges, and the abutting end parts of the two tubular ceramic members having radially thickened wall portions for increasing the bonded areas and strengthening the portions of the walls to which the flanges are attached.

7. The invention in accordance with claim 6 in which the adjacent portion of the two flanges are spaced apart and in which the uppermost flange has a downwardly projecting skirt outwardly of'the lower member for shielding the adhesive bond and preventing accumulation of moisture between the flanges.

8. A composite ceramic housing for electrical apparatus comprising two tubular ceramic members having abutting end parts with closely fitted adjoining end surfaces, and a central opening therein extending longitudinally through the members, a radially enlarged portion at the abutting end of each of the ceramic members to provide an increased area of abutting surface and a radially projecting shoulder on the exterior of the member, a hardened body of resin adhesive between the said end surfaces bonded to and uniting the ceramic members, a flange for a first one of the said ceramic members comprising an annular metallic member having the inward part thereof bearing upon the shoulder and an outward portion extending longitudinally over the bonded end surfaces and a flange for the second one of the said ceramic members comprising an annular metallic piece bearing upon the shoulder of the second ceramic member and upon the interior part of the said downwardly projecting portion of the first flange member and screw means compressively securing the two flange members.

9. The invention in accordance with claim 8 in which the lower flange member has openings for draining accumulated moisture between the flanges.

10. A lightning arrester of the type having a plurality of serially connected arrester elements comprising an elongated ceramic housing having a central opening therein extending longitudinally through the housing, a metallic end fitting at each end of the housing, a plurality of lightning arrester elements within the housing, with means electrically connecting the said elements only to the end fitting at each end of the housing, the said housing comprising at least two tubular ceramic members with the adjacent ends thereof in opposed aligned relationship, flange means at the said adjacent end of each of the members with means for transmitting longitudinally directed forces between the flange means and the ceramic member and means compressively connecting the two flange means, and a hard body of electrical insulating material between the ends of the said ceramic members adhering to the end surfaces thereof and uniting the members to seal the interior of the housing and maintain the electrical insulating strength of the housing in the radial direction thereof within the said flange means.

11. The invention in accordance with claim 10 in which the flange means, in each instance, constitutes an annular metallic piece surrounding the ceramic member with a cementitous body between the annular piece and the ceramic piece.

12. The invention in accordance with claim 10 in which the ceramic members are formed with radially projecting shoulders at the adjacent ends thereof and the flange means, in each instance, constitutes an annular metallic piece surrounding the body and bearing upon the shoulder.

1 -3. A lightning-arrester of the type having. a plurality ofi serially. connected arrester elements, comprising an elongated: housing. having. a central; opening t-herei-n' ex.- tending longitudinally through the housing, a metallic end fitting. at each end of the housing for closing. the interior thereof and supporting thehousing, a columnof lightning arrester elements within: the housing with means electrically connecting the said. elements in: series between the said end fittings, the said housing comprising: at least two separately formed tubular cenamic members with the adjacentends thereof in abutting relationship, means at the adjacent ends of the ceramic members securing the members against relative transverse movement in the radial direction, and means integrally uniting the ceramic parts at the abutting ends thereof, the said last named means constituting aninsulating barrier at the juncture ofthemembers'in the radial direction thereof.

14;. A composite ceramic housing for electrical apparatus comprising two tubular ceramic membershaving abutting end parts with closely fitted adjoining end surfaces and a central opening extending longitudinally through the entire housing, means. at the adjacent ends of the ceramic members extending circumferentially about 8 the members and securing the. members against relative transverse movement in the radial direction, and means integrally uniting the ceramic parts at the abutting ends thereof, the-said last named means constituting an insulating barrier at the juncture of the members in, the radial direction thereof References Cited in the file of this patent UNITED STATES PATENTS 1,655,972 Pineles Jan. 10, 1928 1,689,781 Jacobs Oct. 30, 1928 1,754,158 Goodwin Apr. 8, 1930 2,135,085 Ludwig et a1 Nov. 1, 1938 2,151,559 McEachron Mar. 21, 1939 2,542,805 Fink Feb. 20, 1951 2,586,285 Acker'mann Feb. 19, 1952 2,661,439 Stoelting Dec. 1, 1953 2,677,072 DeVal Apr. 27, 1954 2,783,410 Manke Feb. 26, 1957 2,795,725 Strab June 11, 1957 FOREIGN PATENTS 478,212 Canada Oct. 30, 1951

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