DEVICE FOR EXTENDING TUBES IN WELL Russian patent published in 2012 - IPC E21B29/10 

FIELD: mining.

SUBSTANCE: device includes housing with central channel, threads for connection with downhole equipment and recesses on the external surface in which there are rollers with axes with possibility of restricted radial movement, hydraulic annular piston inserted into housing central channel with possibility of longitudinal movement downwards and spring-loaded upwards. The piston is equipped with outer conical surface expanding upwards and interacting with rollers from inside that are equipped with extending and calibrating outer surfaces. Annular piston is assembled and consists of lower thrust bushing leaning on a spring and upper conical shaft inserted into housing central channel with possibility of rotation. Shaft conical surface consists of two areas, the lower one is done with the possibility of interaction with extending roller surface and the upper area done with large angle interacts with calibrating surface of roller in piston lower end position. Conical shaft is equipped with changeable head with calibrated hole.

EFFECT: increase of reliability, working efficiency, service life.

3 cl, 3 dwg