SHUTOFF VALVE Russian patent published in 2006 - IPC E21B34/02 

FIELD: gas industry, particularly gas and oil flowing well protection during critical pressure decrease (increase) in well line.

SUBSTANCE: shutoff valve comprises body with inlet and outlet nipples, seat with gate, pilot mechanism, as well as adjusting and cocking devices. The pilot mechanism is made as vertical spring-loaded rod and horizontal piston with sealing means. Lower rod end is connected with the gate by link. Flat longitudinal surfaces with single transversal rests are formed in central parts of the rod and the piston. The rod and the piston may cooperate one with another so that rod rest is arranged over the piston rest. Shutoff valve adjusting device includes adjusting nut and spring brought into cooperation with the piston. The cocking device is made as outer cocking bush threadedly engaging the body and cocking bush, which may freely slide along upper rod end. The cocking bush is connected with outer cocking bush.

EFFECT: simplified structure, improved responsiveness, reliability and accuracy of valve operation.

2 dwg