Fluid level measurement device - has two pressure sensors, one immersed in fluid and other in air, connected to Wheatstone bridge circuit

摘要

The device described measures the level of a fluid and comprises one or more detectors which are sensitive to fluid pressure as a function of its level and to external parameters which effect the result of the measurement. A first detector (1) is sensitive to the pressure exerted by the fluid and by the atmosphere. A second detector (10) similar to the first (1) is sensitive to atmospheric pressure only. A differential measurement is made in appropriate electronic circuits, together with compensation for the influence of another parameter, e.g. temperature on the result. The output signal is proportional to the level of the fluid. The detectors (1,10) may be strain gauges with membranes acting as the sensitive element. The first detector is immersed in the fluid whose level is to be determined and the second detector is in free air. A wheatstone bridge system is used to determine the difference signal.