ULTRASONIC DISTANCE METER FOR HOT OBJECT WITH WATER FLOW

PURPOSE:To obtain the measuring accuracy for a hot object to be measured as well as for a cold object to be measured by correcting measured distance with the thickness of a stream film on the surface to be measured as calculated based on outputs of first and second thermometers for measuring surface temperature of the object to be measured and the temperature of a liquid flow column. CONSTITUTION:The thickness of steam film in a steam film corrector 15 is calculated by use of a heat transfer coefficient at the impact point of a water flow. As in the case of the conventional distance meter, the distance L' ignoring the steam film thickness is calculated with an ultrasonic transmitter/receiver 2, a water flow column 4, a pulse generator 6, a gate circuit 7, a clock pulse circuit 8 and a counting circuit 9. The distance L' from the calculation circuit 9, the surface temperature thetaS of an object to be measured from surface temperature meter 13, the temperature of a water from a water temperature meter 14 are supplied to a steam film thickness corrector 15. The corrector 15 calculates the thickness of the water vapor film based on these input data and data prememorized. In this manner, the distance L is determined and outputted allowed for the thickness of the water vapor film.