BOREHOLE SHUTOFF VALVE Russian patent published in 2004 - IPC

FIELD: underground oil storage tanks, particularly for preventing atmospheric emission of tank contents when wellhead seal failures, for closing annular and tube spaces of technological tank well.

SUBSTANCE: shutoff valve comprises body with stationary piston, control chamber hydraulically communicated with sealed working chamber of sliding flap formed between body and stationary piston. Body also has ground-based control system and working chamber of disc flap formed between body and bushing with seat sliding inside body. Spring-loaded disc flap cooperating with bushing seat is arranged in lower body part. Body has cylindrical grooves with return springs. Working chamber and return springs of sliding flap are arranged accordingly under stationary piston and above stationary piston. Return springs of disc flap are located above and under differential bushing piston. Distance from lower ends of sliding and closed disc flaps is equal or more than bushing length. Central open flow area dimension of shutoff valve is not less than 100 mm.

EFFECT: possibility of automatic simultaneous closing annular and tube spaces of operational pipe string during emergency incidents in wellhead.

1 dwg