STEAM CUTOFF DEVICE FOR UNDERGROUND WELL IN THERMAL-MINING DEVELOPMENT OF OIL FIELDS Russian patent published in 2017 - IPC E21C41/24 E21B43/24 

FIELD: oil and gas industry.

SUBSTANCE: steam cutoff device includes a housing hydraulically connected to the wellhead, a main exhaust valve whose seat is installed in the bottom of the housing, and a float actuator of the exhaust valve. The cutoff device is provided with an additional exhaust valve, the seat of which is also installed in the housing bottom, the valve locking elements being arranged with the possibility to be sequentially opened into the housing by one float actuator. The float actuator of the exhaust valves is made in the form of a console hinged in the housing with the possibility of moving the cantilever in the vertical plane, at the free end of which the float is fixed, wherein the discharge valves are installed on opposite sides of the console. A rod, on which thrusts rigidly connected with the locking elements are freely mounted, is installed and rigidly fixed perpendicular to the console. The thrust length of the additional exhaust valve shutoff element is larger than the thrust length of the main valve shutoff element, each valve shutoff element being made with a guide shank on the bottom, whose length is larger than the full stroke length of the shutoff element.

EFFECT: improved operation reliability of the cutoff device.

3 dwg, 1 ex