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.
Level gauge consists of a metal body, machined to have an internal chamber and one or more front windows. On each window a special high resistance glass is used with sealing joint and metal cover plate hold by bolts and nuts.
Level devices operate under three main different principles:
- The position (height) of the liquid surface
- The pressure head
- The weight of the material
Types of Level Gauge:
There are commonly 3 types of level gauges used:
- Reflex level gauge
- Transparent level gauge
- Magnetic type level gauge
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.