CUT-OFF VALVE Russian patent published in 2014 - IPC E21B34/06 F16K15/06 

FIELD: oil and gas industry.

SUBSTANCE: cut-off valve is installed in the tubing string over the hydraulic device and consists of a split casing with a hollow plunger is installed in its axial channel with a collar supported by a spring. In the axial channel of the hollow plunger there is a thrust with a bushing installed on it; the bushing has radial openings alternated with axial openings connecting cavity under the hollow plunger over the saddle. In the axial channel there is a bushing with a hollow tube equipped with a disc valve at the end pressed to the saddle by the spring. Between the hollow plunger and the split casing there is a circular chamber coupled hydraulically by a radial opening to the axial channel of the bushing and hollow tube. In the bushing there is a bottom with the central axial channel where a bypass valve is installed with a retainer covering bypass openings in the bottom in initial position and its stroke is limited from bellow by a locking ring.

EFFECT: sealing of the tubing string axial channel from the well cavity at any depth of the well and impact of hydrostatic pressure to the disc valve, filling of the tubing string axial channel by formation fluid at the device running in to the well, opening of the disc valve at excess pressure generation in the axial channel of the tubing string with free passage of hydraulic fluid to the device placed below.

2 dwg