Capacitance type temperature compensation oil level measurement sensor

Abstract

The invention discloses a capacitance type temperature compensation oil level measurement sensor which has high positioning accuracy and can achieve the effects of reducing the parasitic capacitance in the dry capacitance and compensating for the fuel oil level measuring errors caused by temperature variation. The capacitance type temperature compensation oil level measurement sensor is characterized in that an oil level measurement module comprises three coaxial metal tubes; the oil level and the oil mass are obtained depending on variation of liquid media in the tubes; the oil level signal capacitance C in proportion to the oil immersion height is output; a temperature compensation module is fixed at the bottom ends of the metal tubes via a conductor tray and a guide rod, is formed by a temperature sensing module assembled in a protective cover tube, automatically corrects errors caused by temperature difference via the guide rod in the tubes, outputs resistance R and capacitance C of the oil level measurement module, converts the resistance R and the capacitance C to current signals IC and IR forming proportional relations with the capacitance C and the resistance R and transmits the current signals IC and IR to a fuel measurement control system via a socket connected with shielded conductors.

Description

technical field [0001] The invention relates to a capacitive temperature-compensated fuel level measuring sensor mainly used for measuring the fuel oil level height and fuel temperature of an aircraft. Background technique [0002] The capacitive oil level sensor uses the capacitance formed by filling the liquid medium between the positive and negative probes to change linearly with the liquid level, and converts the change in capacitance (that is, the change in liquid level) into a standard electrical signal output. Usually, the sensing part of a general capacitive oil level measurement sensor is a coaxial container. When the oil enters the container, the capacitance between the sensor tube and the sensing electrode changes, and this change is carried out through the conversion of the temperature compensation circuit. Linearity and temperature compensation, output 4~20mA or 0~5V standard signal for display instrument. Because analog components such as bidirectional switche...

AI Technical Summary

Problems solved by technology

[0003] (1) The sensor does not have a fuel temperature measurement component, so it cannot compensate the error caused by the fuel temperature change to the fuel level measurement

[0004] (2) The positioning method between the sensor tubes is generally composed of multiple concentric positioning pins that are vertical in space, which has the problems of poor process technology and low positioning accuracy

[0005] (3) Fuel pollutants are often deposited on the sheaths installed at both ends of the sensor, causing the capacitance value of the sensor to be seriously out of tolerance, resulting in a large parasitic capacitance value

[0006] (4) After the cable in the fuel tank is connected to the signal lead-out end of the sensor, there is no effective stress buffer device. In the aircraft environment, the swing of the wire will have a greater impact on the lug or ring connected to the terminal , easily lead to loose connection

Images