METHOD AND INSTALLATION FOR CALIBRATION OF THICK-WALLED SMALL-BORE PIPES Russian patent published in 1994 - IPC

FIELD: mechanical engineering. SUBSTANCE: mandrel is moved through the pipe at a variable speed by applying high-pressure of liquid to mandrel. As mandrel speed drops below the level of its wedging in pipe, liquid pressure is brought to act on the opposite end of the mandrel. Installation comprises a casing with the mandrel, two devices for fixing the pipe ends with mandrel-catching chambers, a bath with working fluid, a HP device comprising a plunger pump and nonreturn valves, and a fluid-distributing device comprising a control valve, a hydraulic damper in the form of a stop with jet and a two-position valve. EFFECT: improved functional and operating characteristics. 5 cl, 2 dwg