Abstract

Liquid level measurement is considered one of the four primary process measurement parameters, ie, temperature, pressure, flow, and level. Measurement of any of the parameters is difficult due to the harsh conditions present in many processes. High temperature, high pressure, corrosive environments, turbulence, etc, are a few of the conditions a measurement device must endure if it is to fulfill its goal of accuracy and dependability. Due to these factors, numerous and various level measurement devices have been developed to effectively handle particular types of applications.

The following approaches are covered in the article: sight glasses, dip stick, magnetic liquid level indicators, floats, displacers, buoyancy, conductivity, capacitance, pressure/differential pressure, ultrasonic, microwave, fiber optic, thermal disposition, magnetostrictive, phase tracking, servo gauge, and radiation.