(19)

(11)

EP 0 201 490 A1

(12)

(43) Date of publication: 20.11.1986 Bulletin 1986/47 (21) Application number: 85900279.0 (22) Date of filing: 09.11.1984

(51) International Patent Classification (IPC):  E21B 23/ 00( . ) F04B 47/ 08( . ) (86) International application number: PCT/US1984/001846 (87) International publication number: WO 1986/002971 (22.05.1986 Gazette 1986/11)

(84) Designated Contracting States: AT BE CH DE FR GB LI LU NL SE (71) Applicant: WATTS, John, Dawson Houston, TX 77092 (US)	(72) Inventor: WATTS, John, Dawson Houston, TX 77092 (US)