(19)

(11)

EP 0 580 802 A1

(12)

(43) Date of publication: 02.02.1994 Bulletin 1994/05 (21) Application number: 92917314.0 (22) Date of filing: 17.04.1992

(51) International Patent Classification (IPC):  B01F 3/ 04( . ) (86) International application number: PCT/US1992/003199 (87) International publication number: WO 1992/018228 (29.10.1992 Gazette 1992/27)

(84) Designated Contracting States: DE FR GB IT (30) Priority: 18.04.1991 US 19910687171 (71) Applicant: COSTAR CORPORATION Cambridge Massachusetts 02140 (US)	(72) Inventors: BUTZ, David Westfort, MA 01886 (US) BERRY, Eric Merrimack, NH 03054 (US) (74) Representative: Read, Matthew Charles, et al  Venner Shipley & Co. 20 Little Britain London EC1A 7DH London EC1A 7DH (GB)