Level Gauge

Level gauge, abbreviated as LG, also known as a level sensor or level transmitter, is a device used to measure the level of fluids (liquids or solids) in a container or tank.  It provides continuous or periodic information about the level of the substance being measured.  It is an instrument that is used to measure the top of fluid in a vessel or tank.  It can be as simple as a level switch that provides a discreet output to a pump, PLC or alarm an operator.  It may be able to provide an analog output to indicate level and/or interface.

Common Level Gauge Types

Instrumentation level gauges employ various technologies and principles to determine the level of the substance accurately.

Float Level Gauges  -  These gauges use a float that rides on the surface of the liquid.  As the level of the liquid changes, the float moves up or down, which is detected by a sensor, such as a magnetically coupled device or a potentiometer.
Ultrasonic Level Gauges  -  Ultrasonic level gauges use ultrasonic waves to measure the distance between the sensor and the surface of the liquid.  By measuring the time it takes for the ultrasonic waves to travel to the liquid surface and back, the level of the liquid can be determined.
Radar Level Gauges  -  Radar level gauges utilize radar waves to measure the distance from the sensor to the liquid surface.  They are particularly useful for measuring levels in tanks with corrosive or viscous liquids, or in environments with extreme temperatures.
Capacitance Level Gauges  -  Capacitance level gauges work based on the principle of changes in capacitance between two conductive plates.  As the level of the liquid changes, the capacitance between the plates changes, allowing the device to determine the level of the liquid.
Pressure Level Gauges  -  Pressure level gauges measure the pressure exerted by the liquid column in the tank.  By measuring the pressure at the bottom of the tank and compensating for atmospheric pressure, the level of the liquid can be determined.

These are just a few examples of the many types of instrumentation level gauges available.  The choice of level gauge depends on factors such as the type of liquid or solid being measured, the operating conditions (temperature, pressure, etc.), and the accuracy and reliability requirements of the application.