Magnetic gauges can often be used in applications where a sight glass is not practical.
A Magnetic gauge uses the attraction between two magnets to follow the level of a liquid.One magnet float on the surface of the liquid.The other magnet is inside a nonmagnetic tube passing through the liquid.
The passing through the liquid is made of a nonmagnetic metal.The magnet inside the tube is balanced by a counterweight so that it can rise or fall easily.The ring-shaped floating magnet fits around the outside of the tube and follows any change in liquid level.The magnet inside the tube follows the floating magnet and moves the indicator along a calibrated scale.
Magnetic Gauges should not be used to measure liquids that can cause the floating magnet to stick to the tube.
The material for the tube itself must be able to withstand the temperature, pressure and chemical action of the liquid that is being measured.