| 摘要 |
PURPOSE:To improve the reliability of temperature measurement by measuring the temperature of a pipeline in accordance with relations between the phase difference of a voltage and a current, which are supplied to a power cable connected to a heating body arranged in the pipeline, and the magnitude of the current. CONSTITUTION:Power cables 2 and 4 connected to a current power source 1 are connected into a loop from one end of the pipeline consisting of a steel pipe 3 to the other end so that a current I is flowed to an AC power source 1, the cable 2, the pipe 3, the cable 4, and the AC power source 1. A current transformer 5 which measures the phase difference between the supplied current I and a supplied voltage V and the supplied current I, an ammeter 6, a phase difference measuring device 7, and band-pass filters 8 and 9 are connected. The magnitude of the supplied current I is used as a parameter preliminarily to set the relation between a phase difference phi and a temperature T as prescribed. Then, the phase difference phi is measured to measure the temperature T of the heating body. |
