| 摘要 |
PURPOSE:To obtain an induction type liquid level gauge of high accuracy for conductive liquids by providing means for detecting the current change of an excitation coil and the temp. change in a liquid level probe and correcting measured values based on these detecting means. CONSTITUTION:A liquid level gauge probe 20 consisting of an excitation coil 22 connected with a low-frequency AC power source 25 and a resistance 26 for detecting excitation current, a detecting coil 23 and a thermocouple 24 which are housed in a guide pipe 21 of a nonmagnetic material, is provided in a vessel 1 in which conductive liquid 2 is contained. The outputs of the thermocouple 24 and the resistance 26 are rectified 33, 37, and are converted to coefficients by coefficient multipliers 35, 39 via A/D converters 34, 38. The output of the detecting coil 23 which detects the change in liquid level as a change in induced voltage is amplified 27, and is rectified 28, and if the output standardizing said output with a subtractor 31 via an A/D converter 29 is multiplied by said coefficient values, the errors owing to the temp. change of the conductive liquid and the errors owing to the change of the excitation current are easily corrected. |
