HYDRAULIC JARS Russian patent published in 2011 - IPC E21B31/113 

FIELD: oil and gas production.

SUBSTANCE: device consists of case and spindle tied with flow string and with released object; case and spindle are interconnected with movable spline couple; also, device consists of cylinder and piston. The piston is connected with a draw and compensation rods packed with seals; also, the piston has a channel equipped with a valve unit communicating cavities of the cylinder divided with the piston and filled with working agent. The cylinder is installed inside the case with a radial gap. Lengthwise slots are made on a section of internal surface of the cylinder interacting with the piston. The case is rigidly coupled with a lower sub. The piston is equipped with split flexible compression springs. Initial gaps in butts of piston rings are equal to zero or near zero when piston is installed inside the cylinder. Spline connection of the case and the spindle is made along a spiral line for performing torque shocks.

EFFECT: prevention of device unauthorized actuating and expansion of its functionality.

3 dwg