| 摘要 |
The apparatus, which is designed to be dragged or pushed through a pipe, comprises several parallel curved arms (1-4) pushed against the sides of the pipe by springs (7). On the outermost point of each arm a wheel (8, 9), or roll, runs against the pipe-wall. Signals are send by a cable (13) indicating the degree of extension of the arms, and thereby the inner dimensions of the pipe. |
