METHOD AND APPARATUS FOR MEASURING CURVATURE AND CURVATURE VARIATIONS IN PIPELINES AND THE LIKE

摘要

1435650 Monitoring pipe curvature electrically AMF Inc 19 April 1974 [16 May 1973] 17214/74 Headings G1M and G1N The curvature of a pipe 12, Fig. 1 is measured by a probe 10 comprising a plurality of cups 16 in a drive section 10A which are propelled by a fluid flowing in the direction of arrows 22, and is coupled to a measuring section 10B consisting of a housing 24 centrally located by two arrays of wheels 26A-D, 28A-D, which are spring-biased to rest on the inner wall 12A of the pipe, the wheel rotations being counted by shaft encoders 26A3 &c. and compared with each other to establish a difference in length of the wall for a given distance of axial travel, which difference is indicative of the curvature. As shown, using one four wheel array 26A-26D, the signals from the corresponding shaft encoders 26A3-26D3 are fed to an instrument section 10C, where the distance travelled is determined from the sum of the shaft rotation signals, and the curvature calculated for a pre-set travel. This is recorded on magnetic tape stored in housing 30 for subsequent comparison with an initial curvature value for that section, whereby an excessive curvature change can be located. The housing 24 also carries a pendulum on a shaft coaxial with the probe axis and associated with an angle displacement encoder whereby the vertical along the measuring section of the probe is established relative to an opposing wheel pair 26A, 26B, and the curvature components along the vertical and horizontal axes are calculated from the measured curvature components along 26A, 26B and 26C, 26D. The apparatus may also be used to measure the curvature of a pipe with a non-circular crosssection.