AU601224B2

AU601224B2 - Complete insulator having insulating coating molded thereover

Info

Publication number: AU601224B2
Application number: AU79259/87A
Authority: AU
Inventors: Maurice Soucille
Original assignee: Ceraver SA
Current assignee: Ceraver SA
Priority date: 1986-10-02
Filing date: 1987-10-01
Publication date: 1990-09-06
Anticipated expiration: 2007-10-01
Also published as: JP2532889B2; FR2604821B1; JPS6398921A; EP0264684A1; EP0264684B1; DE3750946T2; FR2604821A1; AU7925987A; DE3750946D1; BR8705112A; CA1291229C; ATE116761T1

Abstract

Composite insulator (30) with an insulating covering (36) moulded onto it, comprising a central rod (32) of fibres agglomerated by a synthetic resin, whose ends are solidly connected by sleeve-coupling respectively to two end-fittings (31) and whose lateral wall is provided, by over-moulding, with a covering having ribs made of elastomer; the said covering covers the lateral wall (37) of the said end-fittings (31) so as to provide only one zone (35) necessary for attaching the insulator. <IMAGE>

Description

AUSTRALIA 0122 Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodlged: Accepted: Published: Priority rTI~ i doci ntns t~h !1AllntmTade tne ion 4 9 and is corect I'm s. 9 p

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APPLICANT'S REF,: F 0 15565/DL Namec(s) of Applicant(s): ANONYME DITE CERAVEP.

Address(es) of Applicanit(s): Actual Inventor(s): Address for Service is: .10 Quai Paul Dcuner, 92411 Courbevoje, France.

Maurice SOURCILLE a 900 PH ILL IPS, ORMONDE AIND FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Australia, 1000 Complete Specification for the invention entitled-, COMPLETE INSULATOR tIAVING INSULATING COATING MOLDED THEP.EOVEfl The following statement is a full description of this invention, Including the best method of pcrfotnnIim It knlown to P19 3 84 z- 1A Composite insulator having insulating coating molded thereover The present invention relates to a composite insulator having an insulating coating molded thereover. Such an insulator and a method of manufacturing it are described, in particular, in French patent No. 2 506 997. It comprises a rod of fibers embedded in a synthetic resin with the ends of the rod being fastened in respective blind cavities provided in two metal anchoring end-fittings, with the side wall thereof receiving a coating of elastomer fins which are molded thereover, for example using EPDM E~ \e ne.- op\ee- ve- Each metal end-fitting, described for example in French patent No. 2 541 501, thus has an internal cylindrical housing whose inlet is provided with a flange defining the "inlet plane" of the end-fitting. The creepage distance of the insulator is defined between the "inlet planes" of its two end-fittings.

The insulating coating of the rod must adhere perfectly to athe inside face of the flange in order to prevent any trace of dampness reaching the rod which would cause the insulator to o b deteriorate very rapidly. Further, the inlet to the end- 20 fitting remains a critical region since that is where power Sarcs are likely to occur which will deteriorate rod anchoring and sealing.

Preferred embodiments of the invention avoid these drawbacks.

having an insulating coating molded thereover, the insulator comprising: 000* a central rod of fibers embedded in a synthe isresin; two end-fittings; and a coating of elastomer fins; 2wherein each end-fitting i udes at least one end in the form of a solid cylinder, d each end of said rod is disposed in end-to-end relat ship with the cylindrical end of the correspondin d-fitting and is clamped therewith inside a common eve, and wherein said coating complecely covers the side walls of 7anrct p walls of said

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j'j 1 Jo I 10 Vc The present invention provides a composite insulator comprising: a central rod of fibres embedded in a synthetic resin; two end-fittings; and an insulating coating of elastomer fins molded over said composite insulator whereir each end-fitting includes at least one end in the form of a solid cylinder, and each end of said rod is disposed in end-to-end relationship with the cylindrical end of the corresponding end-fitting and is clamped therewith inside a common sleeve, and wherein said coating completely covers the rod between the common sleeves, the side walls of said sleeves, and at least a portion of the side walls of said 4257i

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1B 0 0 0:*0e ***as 0* 0 2 end-fittings so as to leave uncovered only those zones of the end-fittings which are necessary for insulator fastening purposes.

An insulator is thus obtained having "twofold internal anchoring" and which has numerous advantages. For a given length of insulator, the creepage distance is increased. The anchoring per se is much better protected from the point of view of sealing. Further, the zone where a power arc may occur is at a distance from the anchoring and is on a non-critical portion of the end-fitting.

Any shape of end-fitting may be provided. In particular, the fastening end of the end-fitting may have any of the following shapes: k-nob; fork; peg; ball-receiving socket; eyelet; and Y-shaped fork.

Embodiments of the invention are described by way of example with reference to the accompanying drawings, in which: Figures 1 and 2 are two fragmentary sections through suspension insulators in accordance with the invention; F'igures 3 and 4 show variants of Figures 1 and 2 in which the diameter of the rod is greater than the diameter of the end-fitting; and Figures 5 and 6 show variants of Figures I. and 2 In which the diameter of the rod is less than the diameter of the endfitting.

25 The insulator 30 shown in Figure 1 comprises a central rod 32, and two end-fittings. The end-fitting 31 shown has a cylindrical end 33 of the same diameter as th~e rod 32 and its other end is in the form of a knob 35. These parts are gixed together by inserting the end of the rod 32 and the end of the end-fitting into a tube 34 of ductile metal, and then by sleeve coupling, for example using the method described in Frer'ch patent No. 2 5.UA 546 (equivalent to UK~ patent 2 104 171). The coating of elastomer fins 36 completely covers the tube 34 as well as a large part of the side wall 37 of the end-fitting 31(t leaving uncovered only the zone required for fastening to the knob 35. The coating 36 terminates with a fin 38.

3 This embodiment is particularly advantageous since it is very cheap. The metal part 31 is very simple in shape; the tube 34 may be a steel tube of a kind commonly found in ccmmerce and has no need to be galvanized since it is extremely well protected by the coating 36. In order to obtain perfect adherence between the elastomer coating 36 and the side face 37 of the end-fitting 31 or the side face of the sleeve 34, these side faces should be nleaned in conventional manner and an elastomer-to-metal adherization agent should then be applied.

The initial surface state of the metal faces is not at all critical, aid the quality of the connection between the coating and the end-fitting is quite remarkable: a force of more than N/cm must be applied in order to begin tearing the coating from the surface of the end-fitting. This result is unexpected since in order to mold effectively over the rod and the endfitting and to eliminate all interstices in order to obtain the desired sealing, it is necessary to inject the elastomer under very high pressure, about 50 bars to 60 bars. It would normally have been expected under the effect of such a pressure 20 that the elastomer-to-metal adherization substance would be at least damaged and that bubbles would appear between the metal faces and the coating thereover. This does not happen.

The insulator 40 shown in Figure 2 is very similar to the insulator 30 in Figure 1. The same numerals are used to 25 reference items which are identical. The coating 46 differs from the coating 36 in that it terminates with a sleeve 48.

In the insulator 50 shown in Figure 3, the configuration eta* is similar but the cylindrical end of the end-fitting 51 is of smaller diameter than the rod 52. A metal tube 54 can still be used to provide a sleeve coupling. The coating 56 terminates with a fin 58, whereas Figure 4 shows the coating 66 of an insulator 60 terminating with a sleeve 68.

In insulator 70 of Figure 5, it is the rod 72 which is smaller in diameter than the cylindrical end of the end-fitting 71. A tube 74 is used to provide a sleeve coupling and the elastomer coating 76 terminates with a fin 78, whereas on the insulator 80 shown in Figure 6, the coating 86 terminates with a sleeve 88.

It. 4 Naturally, the invention is not limited to the examples described above. The shapes of the end-fittings could be different.

In a:.l variants the creepage distance of the insulator is longer than in prior art arrangements, in particular by virtue of the fact that additional fins can be provided. The electrical performance of such an insulator is therefore improved.

Further, the path along which drops of water must run prior to reaching the anchorage per se has also been considerably lengthened.

Further, power arcs which used to run the risk of damaging the anchorage in prior art arrangements now take place in the outer end zones of the end-fittings, and this does not cause significant damage.

The end-fittings are made in particular of a material selected from: steel; cast iron; bronze; and aluminum.

The invention is applicable, for example, to suspension I insulators for voltages up to beyond 735 Kvolts.

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Claims

1. A composite insulator comprising: a central rod of fibres embedded in a synthetic resin; two end-fittings; and an insulating coating of elastomer fins molded over said composite insulator; wherein each end-fitting includes at least one end in the form of a solid cylinder, and each end of said rod is disposed in end-to-end relationship with the cylindrical end of the corresponding end-fitting and is clamped therewith inside a common sleeve, and wherein said coating completely covers the rod between the common sleeves, the side walls of said sleeves, and at least a portion of the side walls of said end-fittings so as to leave uncovered only those zones of the end-fittings which Sare necessary for insulator fastening purposes.

2. A composite insulator according to claim 1, wherein the Sfastening zones of said end-fittings are of one of the S following shapes: plate; peg; knob; fork; ball-receiving socket; and eyelet. S

3. A composite insulator according to claim 1 or 2, wherein said end-fittings are made of a material chosen from: steel; cast iron; bronze; and aluminum.

4. A composite insulator substantially as herein described with reference to and as illustrated in the accompanying Sdrawings. S.. S.. S S S. S S S S S 5S DATED: 20 June, 1990. PHILLIPS ORMONDE FITZPATRICK ATTORNEYS FOR: L SOCIETE ANONYME DITE CERVR/ 4255i 5