US 9,810,343 B2
Pressure compensated flow tube for deep set tubular isolation valve
Wade A. Miller, Broken Arrow, OK (US); John E. Burris, Bixby, OK (US); and Michael L. Hair, Tulsa, OK (US)
Assigned to BAKER HUGHES, A GE COMPANY, LLC, Houston, TX (US)
Filed by BAKER HUGHES INCORPORATED, Houston, TX (US)
Filed on Mar. 10, 2016, as Appl. No. 15/66,892.
Prior Publication US 2017/0261120 A1, Sep. 14, 2017
Int. Cl. E21B 34/10 (2006.01); E21B 43/12 (2006.01); F16K 31/122 (2006.01); E21B 34/00 (2006.01)
CPC F16K 31/1223 (2013.01) [E21B 34/10 (2013.01); E21B 43/12 (2013.01); E21B 2034/005 (2013.01)] 32 Claims
OG exemplary drawing
 
1. A safety valve assembly for use in a tubular string, comprising:
a body having a hydraulically operated flow tube to selectively move into and out of contact with a flapper to selectively open and close a passage through said body and said flow tube wherein movement of said flapper selectively opens and closes said passage;
said flow tube sealed to said body defining an isolated annular space in between when said flapper is in an open and a closed position;
a pressure compensation system operable between the passage and said isolated annular space to control differential pressure between said passage in said flow tube and said isolated annular space, said pressure compensation system comprising a movably mounted piston between opposed stops with a pressure relief device that selectively opens if pressure differential across said piston exceeds a predetermined amount.