Capacitance sensor

Abstract

The invention discloses a capacitance sensor, comprising a sensor gauge head, inner electrodes and an outer electrode, wherein the inner electrode is composed of a plurality of independent electrodes; the inner electrodes are the same in inner and outer diameters and are coaxially arrayed; the inner electrodes respectively comprise a top compensation electrode, a multi-section measurement electrode and a bottom compensation electrode from top to bottom; each two sections of electrodes are connected through a connecting piece which is made of an insulating material; the outer electrode is sleeved at the outer parts of the inner electrodes through screw threads, is coaxially mounted with the inner electrodes and is commonly shared by each section of the electrode in the inner electrodes; and the sensor gauge head is connected with the outer electrode. According to the capacitance sensor disclosed by the invention, the influences on liquid level measurement of temperature, pressure, mediums and the like are eliminated and the precision of the liquid level measurement is improved; and furthermore, an electricity leakage phenomenon can be effectively avoided and the linearity of the sensor is guaranteed.

Description

technical field [0001] The invention relates to a capacitive sensor, especially a multi-stage capacitive sensor with self-compensation, which is used for liquid level measurement, especially for aviation fuel oil level measurement, and can effectively eliminate the temperature, pressure and medium changes that cause liquid level measurement. The influence of the liquid level can be achieved with high precision measurement. Background technique [0002] Liquid level is one of the very important industrial physical quantities. In particular, the fuel level is one of the most basic and important physical quantities in the fuel measurement system. Fuel quantity measurement is closely related to flight safety and efficient use of energy. Fuel quantity measurement refers to the measurement of fuel quality. First, the fuel level is obtained through the fuel level sensor, and the fuel volume is obtained through calculation. Combined with the fuel density, the fuel quality is calcu...

AI Technical Summary

Problems solved by technology

[0006] There is following problem in above-mentioned existing capacitive sensor: first, the dielectric constant of air and measured liquid can change along with the change of temperature, pressure etc., so f(d, D, ε 0 , ε r ), g(ε r , h) will change accordingly, and due to the nonlinearity of the function, its change is complicated, making the relationship between the liquid level value and the capacitance value nonlinear, which brings difficulties to the calibration and calibration of the sensor

Secondly, the quality of different types of measured liquids is quite different, and the dielectric constant is also different, which further increases the difficulty of sensor calibration and calibration

Finally, when the electrode of the capacitive sensor reaches a certain length, the interference such as electric leakage is relatively large, resulting in an obvious nonlinear relationship between the liquid level value and the capacitance value

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