Measuring the level of dust and fly ash collected in electrostatic precipitators (ESPs) is a very difficult technical problem. At one utility, level switches were so unreliable that operators could ...

The signal attenuates severely when passing through air, but the presence of liquid greatly enhances transmission. Thus signal strength of the ultrasonic burst serves as the sensing mechanism. Upon ...

They use a buoyant float to gauge a fluid level. In most models, the float carries permanent magnets and encircles a stationary stem. As the float rises or drops with fluid level, the magnetic field ...