The bi-colour level gauge is in principle a transparent gauge in which the centre-piece has a wedge-shaped section. This design makes bi-colour indication possible. Two colour-filters are mounted right in front of the light source of the illuminator – one red and one green. When seen from the front, the red colour filter must always be on the left.
The optical separation of the steam and water spaces is in this case also based on the differential refraction of light in steam and water.
The bi-colour indication utilises the different light breaking coefficients of steam and water: If the red light ray enters the water it is deflected sidewards and absorbed. If it enters the steam space it passes through unhindered and appears in the indication as red. Light rays which pass through the green filter are absorbed in the steam space but pass unhindered through the water space: the liquid column is therefore indicated as green. Bi-colour level gauges were developed specially for high-pressure steam boilers and condensate accumulators.
Bi-colour gauges are not installed with on inclination. If the gauge is mounted in an elevated position the liquid level may be reflected down to the observation platform by means of a system of mirrors (max. sight length approx. 780 mm).
For illuminators, class IP65 EEx d II Ct6, we use 15W-bulbs. Type approved according to ATEX.
Red/green indication can of course be transmitted by TV to a distant observation stand.
Applications
For steam services up to 180 bar (+355, 5°C); in principle it is a transparent gauge, but with a wedge-shaped centre-piece. For direct observation the gauge is provided with an illuminator containing red and green filters.
Indication
Water space – green
Steam space – red
Note: Only KLINGER original parts guarantee a trouble free operation of the gauge glasses. Therefore it is recommended to use only original spare parts for gauge glasses, mica shields, sealing gaskets and cushion gaskets.
