POWER UNIT FOR PIPE UNSCREWING DEVICE Russian patent published in 1997 - IPC

FIELD: mechanical engineering. SUBSTANCE: this relates to unscrewing pipes in any type of wells, primarily for unscrewing pipes of emergency drilling strings assembled on threads of any direction. Provided in body-cylinder of power unit is diaphragm which divides its space into separate chambers. Walls of body have system of longitudinal and radial passages. Accommodated in body-cylinder is tandem-piston which is axially movable. Cylindrical spool is installed by its tail-piece in tandem-piston and can rotate in body-cylinder. Cylindrical spool has delivery and drain passages. At turning of pipe string connected with body-cylinder, power medium is delivered to make tandem-piston reciprocating, and this motion is then converted into rotation movement by means of additional unit - converter. Power unit is reversible. Used power medium is directed for flushing of well. Use of aforesaid power unit improves sealing of moving contacting surfaces of body-cylinder, spool and tandem-piston, simplifies their manufacture, assembling and dismantling, also enhances repairability, reliability and service life. Operation of power unit is possible at ambient temperatures from -5 C to +350 C, moderate corrosiveness and filtration of power medium. EFFECT: high efficiency. 3 cl, 10 dwg