| 摘要 |
PCT No. PCT/AT88/00100 Sec. 371 Date Jun. 5, 1990 Sec. 102(e) Date Jun. 5, 1990 PCT Filed Nov. 23, 1988 PCT Pub. No. WO89/05201 PCT Pub. Date Jun. 15, 1989.Disclosed is a process and apparatus for producing helically-seamed pipes of any cross-sectional shape. The pipe is produced from a flat strip of material marked at intervals that are a derivative of the circumference of the pipe. At least two sensors are arranged at check points along a paraxial line in order to identify any deviation of the marks from the axis and to generate mark-recognition signals. If the signals are emitted simultaneously, the circumference is constant, and if there is a time differential between the signals, correction is needed. |
