| 摘要 |
PURPOSE:To obtain an inner diameter change detector capable of measuring the change in an inner diameter with high accuracy even under such a state that the temp. of an article to be measured changes, by constituting the titled detector so that two displacement detectors are used and heat outputs of both detectors are mutually negated. CONSTITUTION:A dovetail groove 7 and a T-shape projection 6 are formed to the thick wall part on the periphery of a thin walled ring 1 and electrode plates 4b, 4c are provided to the leading end of the T-shape projection 6 and electrode plates 4a, 4d to the dovetail groove 7 while these electrode plates are connected to an external electric capacity bridge circuit. When the inner diameter of a center hole is changed by strain acting on a steam turbine rotor 5, the gap between the electrode plates 4a, 4b and that between the electrode plates 4c, 4d are oppositely changed corresponding to said change and the capacities between the electrode plates change. At this time, one polarity of two electric signals corresponding to the change in these capacity couplings is reversed to add said signals to the other signals and the changes of the electric signals caused by the change in the temps. of the electrode parts are negated.
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