(19)
(11) EP 0 469 330 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
15.04.1992 Bulletin 1992/16

(43) Date of publication A2:
05.02.1992 Bulletin 1992/06

(21) Application number: 91111165.6

(22) Date of filing: 04.07.1991
(51) International Patent Classification (IPC)5H01H 33/70
(84) Designated Contracting States:
DE GB SE

(30) Priority: 03.08.1990 JP 205003/90

(71) Applicant: HITACHI, LTD.
Chiyoda-ku, Tokyo 101 (JP)

(72) Inventors:
  • Tsukushi, Masanori
    Hitachi-shi (JP)
  • Hashimoto, Akira
    Hitachi-shi (JP)
  • Satoh, Minori
    Hitachi-shi (JP)
  • Kurosawa, Yukio
    Hitachi-shi (JP)
  • Hirasawa, Kunio
    Hitachi-shi (JP)
  • Endo, Fumihiro
    Hitachi-shi (JP)
  • Yamagiwa, Tokio
    Hitachi-shi (JP)

(74) Representative: Strehl Schübel-Hopf Groening & Partner 
Maximilianstrasse 54
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Gas blast circuit breaker


    (57) A gas blast circuit breaker comprises an insulation nozzle (8) for blowing extinguishing gas to an arc (9) generated between a stationary contact (1) and a movable contact (2). The nozzle (8) has a throat section (10) into and out of which one of the two contacts (1, 2) is movable and a divergent section (13) provided downstream of the throat section (10). A slanting surface (11) for increasing a reflectivity of energy intensity of the arc (9) is formed on the divergent section (13) of the nozzle (8). The nozzle (8) is formed of a fluoroplastic material and boron nitride powder not more than 15 vol.% added as a filler.







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