Ultrasonic sensors in the chemical and process industries

Ultrasonic sensors offer the possibility of instrumenting chemical and process plant non-invasively. The principles of a range of ultrasonic instruments are reviewed. The parameters which can be determined include liquid level, concentration (or density) of solutions and dispersions (emulsions and slurries), liquid/liquid interface position, flowrate and temperature. The advantages and disadvantages of ultrasonic techniques are discussed and future advances are suggested.