Level Gauge

  • Reflex Level Gauge

  • Reflex Level Gauge

  • Reflex Level Gauge

Reflex Level Gauge

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

Reflex Level Gauge with Level Gauge Glass


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

Reflex Level GaugeReflex 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 zone and gases or vapors in the upper zone; the liquid level is distinguished 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 environmental light is enough. Only during the night an artificial light must be provided.

The different brightness in the two zones is obtained as explained below:

LIQUID ZONE of Level Gauge

This zone appears quite dark when the gauge is in operation and lighted as above said.
Given the construction, most of the environmental light rays incident on the external face of the glass are quite perpendicular to said face and, therefore, not deviated by the glass. These rays reach the glass/liquid interface with an inclination of approx. 45°. The critical angle glass/liquid is always superior to 45°. Therefore the rays incident within the critical angle (practically the totality) are refracted within the liquid and, since the internal walls of the gauge chamber are not reflecting, the rays cannot be seen from the outside. In fact the zone will appear dark, nearly black, to the observer.

GAS/VAPOR ZONE of Level Gauge

This zone appears almost silver bright to the observer.
As for the liquid zone, the light rays reach the glass/gas-vapor interface with an angle around 45°. Since this angle is greater than glass/gas-vapor critical angle, the rays are not refracted , but totally reflected making 90° turn, thus reaching the nearest glass/gas-vapor interface again with angle of 45°. For same reason they will be reflected and turned by 90° towards the observer, to whom the zone will appear silver bright.


Reflex glass level gauges can be used in most of the cases and offer great advantages in terms of: low initial cost, low operating cost, easy level reading.

Reflex level gauges cannot be used in certain cases as for example:

  • when the separation level between two liquids has to be read (interface).

  • when besides the level indication, the observation of the liquid colour is required.

  • when the process fluid is high-pressure water steam, since in this case the glass must be protected from the solvent action of the boiler water by using mica shields.

  • when the process fluid is such that can corrode the glass (e.g. high temperature alkaline solutions or hydrofluoric acid), since ica shields or Polytrifluorochloroethylene shields must be used to protect the glass.

level gauge glass of LEVEL GAUGE

Online shopping allows you to easily compare different gauges and each specification. With the help of level gauge glass, you can easily order the items you need. You can find the products you need, get the pressure gauges you need with fast shipping options and install them quickly. Level gauges can be used to assemble new equipment, perform repairs, or make equipment easier to read and use.


Knowing the level of boilers and water tanks is important to ensure effective operation. Level gauge glass provides a variety of tubular level level gauges, allowing you to effectively monitor the level of any container. Through a series of different configurations, functions and prices, you can easily find the level gauge that suits your needs.


The level gauge glass provides a tubular liquid level gauge, which is suitable for almost any container and any configuration, even those that are difficult to reach or inconvenient to place. In any case, you can find water meters and water meters for other liquids, even if the liquid is under high pressure, stored at high temperature or corrosive. The level gauge is specially designed to withstand harsh environments, so it will not crack, bend or break even in the harshest environment. Different water level gauges are made of bronze or stainless steel, and are equipped with various safety devices and other functions for ease of use.

TAGS: Level Gauges
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