RELIEF VALVE Russian patent published in 2018 - IPC E21B34/12 E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the drilling and repair of oil and gas wells and can be used to isolate trouble zones when drilling wells. Relief valve, located above the expansion head and below the hydraulic jack, comprises a hollow body and a hollow stem inserted telescopically with limited movement in the hollow body. Hollow body and hollow stem are connected respectively to the expansion head and the hydraulic jack. Hollow stem is equipped at the bottom with a passageway centraliser having holes, longitudinal samples and a cone in its lower part, the cone being equipped with an elastomeric sealing ring. When the hollow stem moves downwardly from the hollow body, the cone of the passageway centraliser tightly engages with a corresponding supporting conical surface formed in the lower part of the hollow body.

EFFECT: technical result consists in increasing the operational reliability of the equipment used in the isolation of trouble zones when drilling or repairing wells.

1 cl, 3 dwg