Fluid quantity indicator esp. for aviation fuel - uses capacitive sensing probes with capacity change proportional to amount of fluid in tank or container

摘要

The improved fluid quantity indicator, such as for aviation fuel, is of the type utilising capacitive type sensing probes in which capacitance change occurs proportional to the amount of fluid in a tank or container due to the dielectric constant of the fluid being different from that of air. Microprocessor control provides display and totalising control in conjunction with automatic compensation for the zero fluid capacitance variation in a tank and automatic adjustment of the fluid full scale reading for variation in fluid tank capacitance. The microprocessor controls two independent digital servo loops.