DEVICE FOR PIPE EXPANSION INSIDE WELL Russian patent published in 2008 - IPC E21B29/10 

FIELD: well drilling and overhaul, particularly cutting or destroying pipes, packers, plugs, or wire lines, located in boreholes or wells.

SUBSTANCE: device comprises body with central channel and depressions made in outer surface thereof and adapted to receive rollers with upper and lower axles. Annular piston is located in central body channel. The piston is spring-loaded from upper side in axial direction relatively the body. Rollers are fixedly connected with upper and lower axles and are installed in the body to provide roller rotation and limited radial displacement within gap. Inner annular recess is made in body over depressions. Cylindrical ledge of outer piston surface is installed in the annular recess. Inner body surface and outer surfaces of the piston and the cylindrical ledge define hydraulic chamber communicated with annular piston interior through radial orifices of the piston. Body may slide in axial direction relatively the piston. Lower part of annular piston is provided with outer conical surface, which may communicate with roller surfaces from within. Thread for device connection with downhole equipment is created at upper annular piston side.

EFFECT: decreased axial loads applied to body, simplified structure and decreased material inputs.

1 dwg