EP0023144A1 - Verfahren zum Befestigen eines metallischen Einsatzes in einem elektrischen Porzellanisolator und nach diesem Verfahren hergestellter Isolator - Google Patents

Verfahren zum Befestigen eines metallischen Einsatzes in einem elektrischen Porzellanisolator und nach diesem Verfahren hergestellter Isolator Download PDF

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Publication number
EP0023144A1
EP0023144A1 EP80302446A EP80302446A EP0023144A1 EP 0023144 A1 EP0023144 A1 EP 0023144A1 EP 80302446 A EP80302446 A EP 80302446A EP 80302446 A EP80302446 A EP 80302446A EP 0023144 A1 EP0023144 A1 EP 0023144A1
Authority
EP
European Patent Office
Prior art keywords
insert
porcelain
metallic insert
insulator
electrical insulator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP80302446A
Other languages
English (en)
French (fr)
Inventor
David H. Reighter
Ira O. Knickerbocker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gould Inc
Original Assignee
Gould Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gould Inc filed Critical Gould Inc
Publication of EP0023144A1 publication Critical patent/EP0023144A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B19/00—Apparatus or processes specially adapted for manufacturing insulators or insulating bodies
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B17/00—Insulators or insulating bodies characterised by their form
    • H01B17/38—Fittings, e.g. caps; Fastenings therefor
    • H01B17/40—Cementless fittings

Definitions

  • the need to attach electrical components such as wires and the like to insulator bodies is usually satisfied by bolting the component to the body.
  • the insulator bodies are usually made of porcelain and any threads in such porcelain bodies are so difficult to produce that they are rarely, if ever, made. If they were produced'for some specific reason, a bolt or other fastener inserted in these threads easily strips the threads so that the attached component readily pulls loose from the insulator body.
  • To make attachments to porcelain it is conventional to cement a metal cap to the insulator body and to attach the electrical components to the metal cap.
  • the conventional metal caps have three major disadvantages, namely they present a large area of the conductive metal, the cap is the most expensive part of the insulator structure, and the incompatibility of the thermal characteristics of the metal and the porcelain gives rise to additional problems. Despite these disadvantages, the metal cap has been considered necessary and is in widespread commercial use.
  • a method of fixedly positioning a metallic insert in a porcelain electrical insulator body comprising vibrating an uncured polymer concrete comprising an admixture of acicular aggregate and a synthetic resin binder therefor against at least one outer surface of the metallic insert and curing the polymer.
  • a porcelain insulator body 1 is prepared in a conventional manner except that the body is provided with one or more recesses 2 which are arranged to receive a metallic insert 3.
  • the metallic inserts 3 can be made of any suitable metallic material such as steel or aluminium and can be formed into any desired shape.
  • the insert 3 can be cylindrical and the recess 2 can be of complementary annular shape. Since the-main purpose of the insert 3 is for attaching electrical conductors to the insulator 1, the insert 3 preferably has a central hollowed-out portion 4 which is threaded at 5.
  • the outer surface of the insert 3 is preferably knurled.
  • the insert 3 is bonded into the recess or cavity 2 of the insulator 1 by a polymer concrete 6 which is a mixture of a curable resin and an acicular aggregate.
  • the polymer can be any curable resin, preferably electrical insulation grade, which will bind the aggregate particles together and will substantially fill the porosity when it is hardened. Accordingly, epoxy resins, polyester resins, polyurethane resins, polyolefin resins, silicon resins and the like can be used.
  • the polymer is chosen from commercially available products on the basis of its physical aspects, electrical characteristics, hydrophobic characteristics, ability to bind the aggregate and handleability.
  • the preferred polymer is an electrical insulation grade epoxy resin. It will be understood by those skilled in the art that the polymer can contain a curing agent which is arranged to be effective in other than ambient conditions.
  • the epoxy resin polymer it is preferred to formulate the epoxy resin polymer with a suitable hardening agent and a catalyst, such as an anhydride or amine, which cures the epoxy resin at elevated temperature. It is also preferred to use a polymer which has a modulus of elasticity in the range of about 2-10 x 106 psi (about 1.4-7 x 105 kg/cm 2 ) because it permits some mismatch in the thermal expansion characteristics of the porcelain insulator and the metallic insert.
  • the majority of the aggregate particles are acicular particles.
  • the acicular particles constitute about 65-75% of the aggregate.
  • Any electrically insulating material which can be obtained in acicular shape can be used and it has been found that electrical grade porcelain when crushed forms an excellent acicular aggregate with all of the desired properties.
  • the remainder of the aggregate can be those materials which are normally used as fillers in synthetic organic polymer insulations.
  • the conglomeration of materials forming the aggregate should have a variety of particle sizes to reduce the amount of volume which will have to be filled by the binder portion of the concrete. Preferably at least two different particle sizes of acicular material are used.
  • the binder is usually the most expensive material in the polymer concrete, it is preferred to keep its concentration in the binder-aggregate admixture as low as practical. In general, the aggregate will be about 75 -95% of the admixture, preferably about 80-90%.
  • the polymer concrete 6 is placed in the recess 2 and the insert 3 is vibratorily inserted therein.
  • the insert and-concrete arrangement can be prepared in a suitable mould and the resulting larger insert inserted into the recess 2 and bonded therein with additional polymer concrete or a different cement. It is necessary to vibrate the insert in the concrete and it is believed that this results in the alignment of the acicular aggregate in such a way as to form a strong cement-insert bond. Such a bond is strengthened considerably when the insert has an irregular outer surface.
  • the amplitude of vibration is not critical and can be varied as desired as long as it is not so violent as to trap air in the admixture.
  • Vibration is continued for a length of time which is a function of the amplitude and the temperature conditions. Vibration should be continued at least until the extrudition'of binder resin on the surface of the admixture can be observed, and preferably until such extrudition has substantially ceased. Such observation of extrudition of a vibrating mixture is similar to that encountered when vibrating Portland cement concrete.
  • the admixture When vibration is complete, the admixture is cured by raising the temperature to or above the curing temperature of the resin binder. As is known in the art, voiding can be eliminated durin5 curing by applying slight pressure to the admixture.
  • inserts 3 place very high shear stresses on the concrete 6 during tension or cantilever loading because only a small surface- area of the concrete 6 is in contact with the inserts 3.
  • the shear strength of the polymer concrete used permits a proportional decrease in the area required to distribute the shear forces.
  • Porcelain insulators were prepared having recesses to accept a metallic insert. 148 parts of a hydantoin epoxy resin (XB-2793 from Ciba Geigy Corp.), 174 parts of methyl tetrahydrophthalic anhydride, 0.75 parts benzoyl dimethylamine, 4 parts of Modaflow flow additive in 50% of the epoxy, 756 parts of 16-mesh porcelain, 396 parts of through 30 on 100 mesh porcelain and 510 parts of 325 mesh crushed quartz were combined in a Ross blender and mixed under approximately 30 inches of mercury vacuum at 90°C for four minutes. The porcelain insulators were placed on a vibratory table and the vibration begun.
  • a hydantoin epoxy resin XB-2793 from Ciba Geigy Corp.
  • methyl tetrahydrophthalic anhydride 0.75 parts benzoyl dimethylamine
  • Modaflow flow additive in 50% of the epoxy 756 parts of 16-mesh porcelain, 396 parts of through 30 on 100 mesh porcelain and 510
  • the recesses were filled with the admixture while vibrating and a steel insert having a hollow threaded centre and a medium knurl surface was placed into the admixture at the desired point. Thereafter, the cement was cured for 3.5 hours at 150°C. Repetitive thermocycle testing over a range of -40° to +150°C was accomplished without any failures. Stressing the insert resulted in failure of the concrete rather than insert. Similarly, all torsion testing exceeded the thread strength of the insert at 172 ft. lbs. and in some cases, deheading the hex bolt at less than this value.

Landscapes

  • Insulating Bodies (AREA)
  • Insulators (AREA)
EP80302446A 1979-07-18 1980-07-18 Verfahren zum Befestigen eines metallischen Einsatzes in einem elektrischen Porzellanisolator und nach diesem Verfahren hergestellter Isolator Withdrawn EP0023144A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US5854979A 1979-07-18 1979-07-18
US58549 1979-07-18

Publications (1)

Publication Number Publication Date
EP0023144A1 true EP0023144A1 (de) 1981-01-28

Family

ID=22017501

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80302446A Withdrawn EP0023144A1 (de) 1979-07-18 1980-07-18 Verfahren zum Befestigen eines metallischen Einsatzes in einem elektrischen Porzellanisolator und nach diesem Verfahren hergestellter Isolator

Country Status (2)

Country Link
EP (1) EP0023144A1 (de)
JP (1) JPS5641617A (de)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH278740A (de) * 1950-03-06 1951-10-31 Oerlikon Maschf Keramischer Isolator mit Metallarmaturen.
DD120042A1 (de) * 1975-07-03 1976-05-20
DE2459146A1 (de) * 1974-12-14 1976-06-16 Felten & Guilleaume Dielektra Verfahren zur herstellung einer kittverbindung aus giessharzbeton fuer die verbindung von metallarmaturen und porzellan fuer hochspannungsgeraete

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH278740A (de) * 1950-03-06 1951-10-31 Oerlikon Maschf Keramischer Isolator mit Metallarmaturen.
DE2459146A1 (de) * 1974-12-14 1976-06-16 Felten & Guilleaume Dielektra Verfahren zur herstellung einer kittverbindung aus giessharzbeton fuer die verbindung von metallarmaturen und porzellan fuer hochspannungsgeraete
DD120042A1 (de) * 1975-07-03 1976-05-20

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
kunststoffe, band 41, heft 12, dezember 1951, m}nchen k.mayer hans "erfahrungen }ber die verarbeitung und anwendung von araldit als bindemittel und als giessharz", pages 457-462 pages 460, 461 *
plastics engineering handboox of the society of the palstics industry, inc. 3rd edition, 1960 reinhold publishing corporation, new york page 366; fig. *

Also Published As

Publication number Publication date
JPS5641617A (en) 1981-04-18

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

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STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19820102

RIN1 Information on inventor provided before grant (corrected)

Inventor name: KNICKERBOCKER, IRA O.

Inventor name: REIGHTER, DAVID H.