(19)

(11)

EP 0 289 502 A1

(12)

(43) Date of publication: 09.11.1988 Bulletin 1988/45 (21) Application number: 87900311.0 (22) Date of filing: 02.12.1986

(51) International Patent Classification (IPC):  H01T 19/ 00( . ) H01T 23/ 00( . ) (86) International application number: PCT/SE1986/000547 (87) International publication number: WO 1987/004019 (02.07.1987 Gazette 1987/14)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 20.12.1985 SE 19850006068 03.10.1986 SE 19860004219 (71) Applicant: ASTRA-VENT AB S-177 43 Stockholm (SE)	(72) Inventors: TÖRÖK, Vilmos S-181 34 Lidingö (SE) LORETH, Andrzej S-18400 Akersberga (SE) (74) Representative: Carminger, Lars  Carminger, Uusitalo & Nyberg Patentbyra AB P.O. Box 7274 S-103 89 Stockholm S-103 89 Stockholm (SE)