APPARATUS HAVING MAGNETIC FIELD INDUCING TARGET SIGNAL TRANSMITTER AND POSITION REFERENCE TRANSMITTER FOR DETECTING CONCEALED PIPES - Patent 0503054

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EP 0 503 054 A1

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(43)	Date of publication:
	16.09.1992 Bulletin 1992/38

(21)	Application number: 91918554.0

(22)	Date of filing: 27.09.1991

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International Patent Classification (IPC):

G01V 3/ 10^{( . )}
G01V 3/ 15^{( . )}

G01V 3/ 11^{( . )}

(86)	International application number:
	PCT/US1991/007101

(87)	International publication number:
	WO 1992/006392 (16.04.1992 Gazette 1992/09)

(84)	Designated Contracting States:
	DE FR GB

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Priority:

27.09.1990 US 19900589088

(71)	Applicant: SOUTHERN CALIFORNIA GAS COMPANY
	Los angeles, CA 9000 (US)

(72)	Inventors:
	MOTAZED, Behnam Pittsburgh, PA 15232 (US) SMITH, Bryon Pittsburgh, PA 15221 (US) WHITE, David Pittsburgh, PA 15224 (US)

(74)	Representative: Carmichael, David Andrew Halliday
	G.F. REDFERN & CO., Redfern House 149/151 Tarring Road Worthing West Sussex BN11 4HE Worthing West Sussex BN11 4HE (GB)

(54)	APPARATUS HAVING MAGNETIC FIELD INDUCING TARGET SIGNAL TRANSMITTER AND POSITION REFERENCE TRANSMITTER FOR DETECTING CONCEALED PIPES