Measurement of Levels in Alkali Metals at Temperatures Up to 900 C with Resistometers . Fuellstandsmessung an Alkalimetallen bei Temperaturen Bis 900 C Mittels Widerstan Dsmesselementen

摘要

Level indicators are based on a thin wall being immersed in the tank of which the electrical resistance is measured. The length of thin tube is limited to about 1.5 m because of the material strength. Error due to incomplete temperature compensation amounts to 0.5%. Tests were carried out on potassium at 820 C with no failure. Haynes 25 tubes, which can be used up to 950 C, manufactured. The experimental error is independent of the temperature, the atmosphere over the liquid surface (argon or potassium vapor), and the purity of the potassium. This error is approximately plus or minus 20 millimeters with calibrated instruments. When calibration is done with the instrument mounted on the tank, the error can be reduced to plus or minus 10 millimeters. This accuracy can only be obtained in certain conditions which are explained. Electronic equipment and measuring devices are described. (Author)