IP Library › Granted Patent US 4,538,685
Granted Patent Utility
US 4,538,685 · App. 06/540,080

Locking annulus safety valve

Inventors: Ronald E. Pringle, Paul Black
Patented Case View Patent ↗
Granted: Sep 3, 1985 Filed: Oct 7, 1983
Inventors
Ronald E. Pringle
Paul Black
Assignee (at issue)
Camco Inc.

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Quick Facts
Patent No.
US 4,538,685
App. No.
06/540,080
Filed
1983-10-07
Granted
1985-09-03
Kind
A