| 摘要 |
PURPOSE:To avoid the influence by a change of a dielectric constant caused by the differece in the kind of liquids and the change of liquid temperature, by preparing an electrode to be immersed in a stored liquid and an elctrode immersed always in a stored liquid and comparing the electrostatic capacities of the respective electrodes. CONSTITUTION:An external upper electrode A and an external lower electrode B are provided outside an internal electrode C via an annular air gap G2, and electrostatic capacitance is formed by the electrode A and the electrode C, and the electrode B and the electrode C, and the value 1' thereof is generated as a detection signal. The electrode B is always immersed in a stored liquid, with a constant electrostatic capacity, and the electrostatic capacity of the electrode A changes as the oil surface changes in the vertical direction, thus, after electrostatic capacity when only air intervenes is subtracted from the outputs of detection signal generators 1, 1' in subtracting circuits 2, 2', if the ratio is provided by a dividing circuit 3, it is obtained what times in depth of the electrode A of the whole length in the axial direction of the electrode B has been immersed in the oil. Therefore, if correction 4 is made in correspondence to the oil tank by the output of the dividing circuit 3, and if an indication is performed via an indication driving circuit 5 with an indicator 6, the level of liquid in the tank can be measured. |
