UNLATCHING JOINT Russian patent published in 2010 - IPC E21B17/06 

FIELD: oil and gas industry.

SUBSTANCE: unlatching joint includes upper and lower reducers connected to each other by means of fixture and vessel with corrosive fluid in relation to fixture located bellow bottom part of vessel. At that, joint is equipped with seat movable in axial direction, intended for waste valve fixed in initial position with limit stop and equipped with hammers. Seat housing has annular groove on outer surface comprising together with upper reducer the cavity to arrange vessel with corrosive fluid. Hammer is rigidly connected to the seat and equipped with cover made from material not soluble with corrosive fluid in vessel cavity. Bottom part of vessel has the section having plane of weakness and located opposite the hammer.

EFFECT: device improves reliability and efficiency of works at elimination of accidents related to sticking of tools in well.

4 cl, 2 dwg