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Level gauge is a device which is used to show the level of fluids in fields. Depending on the type of application used, the type of level gauge should be selected. Level gauge is a direct method for measuring the level.

There are commonly 3 types of level gauges used:

1) Reflex level gauge:

Reflex glass level gauges working principle is based on the light refraction and reflection laws.

Reflex glass level gauges use glasses having the face fitted towards the chamber shaped to have prismatic grooves with section angle of 90°. When in operation, the chamber is filled with liquid in the lower part and gases or vapors in the upper part.

The liquid level is well-known by different brightness of the glass in the liquid and in the gas/vapor zone. The reflex level gauges do not need a specific illumination. The day light is enough for seeing the level.

2) Transparent Level Gauge:

Transparent level gauges are always fitted with two plate transparent glasses between which the fluid is contained. The fluid level is indicated as the result of the different transparency of the two media.

To protect glass surfaces from corrosive action of the process fluid, Transparent Level Gauges can be fitted with Mica shields. The transparent level gauge is particularly recommended for applications where the glass needs to be protected from corrosive fluids and high temperatures.

3) Magnetic Level Gauge:

The Magnetic Level Gauge is used to preventive security against leakage, environmental safety, sure and trouble free application with chemically aggressive, pollutant, harmful or poisonous, inflammable or explosive, optically similar fluid interface.

The magnetic level gauge works based on some elementary physical principles:

  • The principle whereby the liquid in communicating vessels is always at the same level
  • Archimedes’s principle according to which a body immersed in a liquid receives a buoyancy equal to the weight of displaced liquid
  • The principle of attraction between North and South poles of two permanent magnets and that of repulsion between like poles.

There is a float in a pipe chamber which is movement with level and up and down accordingly. A flag flower is clamped with chamber. The individual flags or the follower contain an alignment magnet that couples with the float magnets as the float moves up or down within the piping column.

Float movement rotates the flags and changes their color, the position of the follower, or point at which the flags change color, represents the true level.

According to the orientation of each magnet each cylinder will show externally half of its surface of one colour or the other. The indicating scale will be of one colour over the chamber area taken up by gas, or steam phase contrasting with the other colour (e.g. red) over the chamber area taken up by liquid phase.


"Instrumtech" deals in reputed make of Level Gauges available in national and international market.

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