CUTOFF VALVE Russian patent published in 2012 - IPC E21B34/02 

FIELD: oil and gas industry.

SUBSTANCE: invention comprises a casing, inlet and outlet nozzles, an adjustment mechanism comprising spring-loaded horizontal piston and vertical stem that interact with each other by flat longitudinal surfaces with stops and a cocking mechanism. The cocking mechanism consists of a casing bushing, externally threaded and internally double-stepped movable bushings. Besides, the casing holds a seat and a lock connected by an eye with a vertical spring-loaded stem. Section of the inner cylindrical part of the casing is made with a displaced centre along a downward vertical axis, the upper part of the inner double-stepped movable bushing has smaller diametre compared to the lower one, and the non-spring-loaded end of the spring-loaded horizontal piston is smaller along the diametre of the end spring-loaded with the spring.

EFFECT: increased pressure of actuation, simplified design, higher reliability and durability.

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