PURPOSE: To make it possible to detect the limit running distance of an automatic running machine in a pipe line by computing the average speed of the automatic running machine in the pipeline in correspondence with the moving amount of a control cable.
CONSTITUTION: An automatic running machine 20 in a pipe line intermittently advances by alternately pressing and engaging front and rear engaging parts 1 and 2 in an inchworm pattern. A length measuring instrument 13 sends out the signal corresponding to the moving amount of a control cable 8. When the average running speed V for four expansion operating cycles is to be detected at this time, the sending length L of the cable 8 for the nearest four cycles is detected 14 at the final point of the four cycles. The required time (t) for the same expansion operation is detected, and the speed V=L/t is computed 16. Then, at the time point where one cycle has advanced, the speed V is computed by the same way. This procedure is repeated, and the value is displayed 17. At this time, when the running machine 20 travels forward and approaches the limit running distance, the speed is lowered by the resistance for dragging the long cable 8. Therefore, the approach of the running machine 20 to the limit running distance can be detected by detecting the speed V.
KATAHIRA EIJU
KUSUSHIRO SHIGENORI
YOKOYAMA TOMOHIRO
YOKOSUKA KOICHI
TOKYO ELECTRIC POWER CO