(19)

(11)

EP 0 946 238 A1

(12)

(43) Date of publication: 06.10.1999 Bulletin 1999/40 (21) Application number: 96931372.0 (22) Date of filing: 06.08.1996

(51) International Patent Classification (IPC):  B01D 19/ 00( . ) B04C 5/ 10( . ) B04C 9/ 00( . ) B04C 5/ 02( . ) B04C 5/ 13( . ) (86) International application number: PCT/US1996/012858 (87) International publication number: WO 1998/005399 (12.02.1998 Gazette 1998/06)

(84) Designated Contracting States: BE CH DE ES FR GB IT LI NL (71) Applicant: GDT Corporation Phoenix, AZ 85027 (US)	(72) Inventors: MAZZEI, Angelo L. Bakersfield, CA 93307 (US) FORD, Steven D. Clovis, CA 93612 (US) (74) Representative: Baillie, Iain Cameron  Ladas & Parry, Dachauerstrasse 37 80335 München 80335 München (DE)