Abstract: Reports a measurement technique of liquid level in the liquid tank on ship based on the inverted U type capacitor principle.According to the linear relation between the capacitance value of the capacitor and amount of liquid,design the inverted U capacitance sensor with ‘breath’ function and build a capacitance signal detection and processing system to detect the relationship between the detection capacitance value and liquid level height,as well as to study the effect of shaking on liquid level measurement of liquid tank.In addition,the device performance and the measurement error is analyzed.The results show:There is a liner relationship between the capacitance value and liquid level height;in the rolling angle of 20°,the rolling cycle of 3s simulation of the real ship shaking,the relative error of the corresponding detection capacitance of the liquid level is less than 4%.The technology has the characteristics of simple structure,high sensitivity and good stability.It is expected to be widely used in the detection of the dynamic liquid level of the liquid tank.

Key words: marine liquid tank, dynamic liquid level measurement, inverted U capacitance sensor, performance analysis