Eddy currents probe for measuring a gap between a tube and an antivibration bar

摘要

A gap measurement probe for measuring the gap between a tub and an antivibration bar in a steam generator includes a shaft and first and second sensors mounted on one end of the shaft. Each of the sensors includes a coil form having a first portion fastened to the shaft and having a second C-shaped portion surrounding a portion of the periphery of the shaft. A test coil is mounted on the second C-shaped portion of each of the coil forms and the test coils are arranged such that they extend about different portions of the circumference of the shaft so as to sense different portions of the circumference of the tube when the gap measurement probe is inserted in the tube. The coil forms are flexible and have a circumference which is sufficiently large to press the test coils against the inside of the tube to provide for accurate sensing. In addition, the shaft is preset with a C shape at the end on which the sensors are mounted, so that when the probe is inserted in a U-shaped tube, the probe is self-orienting in the U bend of the tube.