(19)
(11) EP 0 474 724 A1

(12)

(43) Date of publication:
18.03.1992 Bulletin 1992/12

(21) Application number: 90908600.0

(22) Date of filing: 30.05.1990
(51) International Patent Classification (IPC): 
G21B 3/ 00( . )
(86) International application number:
PCT/GB1990/000834
(87) International publication number:
WO 1990/015415 (13.12.1990 Gazette 1990/28)
(84) Designated Contracting States:
AT BE CH DE DK ES FR GB IT LI LU NL SE

(30) Priority: 02.06.1989 GB 19890012637
02.06.1989 GB 19890012638
02.06.1989 GB 19890012639
02.06.1989 GB 19890012640
02.06.1989 GB 19890012774
22.11.1989 GB 19890026442

(71) Applicant: JOHNSON MATTHEY PUBLIC LIMITED COMPANY
London EC1N 8JP (GB)

(72) Inventors:
  • COUPLAND, Duncan, Roy
    Buckinghamshire HP11 1EA (GB)
  • DOYLE, Mark, Lawrence
    Alperton Middlesex HA0 1XQ (GB)
  • POTTER, Robert, John
    Berkshire RG2 0DX (GB)
  • MCGILL, Ian, Ray
    Caversham Reading Berkshire RG4 8NH (GB)

(74) Representative: Wishart, Ian Carmichael, et al 
Patents Department Johnson Matthey Technology Centre Blounts Court Sonning Common
Reading, Berks RG4 9NH
Reading, Berks RG4 9NH (GB)

   


(54) IMPROVEMENTS IN MATERIALS