THE TENNESSEE FLUID LEVEL INDICATOR

An effort to produce a low-cost yet accurate fluid level sensor led to the development of the Tennessee Fluid Level Indicator (TFLI) by researchers at The University of Tennessee Agricultural Experiment Station. This device measures fluid levels using a simple weighted tube hanging from a load cell, and can be designed to measure almost any operational range of fluid levels. The TFLI was tested in the laboratory for repeatability, degree of hysteresis, sensitivity to temperature changes, and stability of the calibration relationship with use. In every case the device performed very well, indicating that it will yield fluid level measurements within ±1 mm (0.04 in.) under normal use. Researchers have used the TFLI in the field for more than three years, and have had very little trouble with either drift or reliability. Perhaps most importantly, the TFLI can be constructed and calibrated for less than half the cost of most water-level sensors.