Why is the dual-color water level gauge green for steam and red for liquid?
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Our company’s boiler drum level was previously monitored using a colorless glass plate level gauge, but it has now been replaced with a dual-color level gauge. Normally, it should be red for steam and green for liquid, but in reality it shows green for steam and red for liquid. I’d like to ask the experts what the reason is.
A dual-color level gauge utilizes the different refractive indices and reflection properties of light in various media; by means of color filters, it makes the liquid phase appear green while the gas phase appears red, thereby indicating the water level in the steam drum. The light emitted by the light source passes through the red and green filters before reaching the liquid chamber of the level gauge. In the gas phase portion of the cavity, red light is emitted straight forward, while green light is emitted at an angle and absorbed by the cavity walls ； In the liquid phase portion of the cavity, due to the refraction of water, green light is directed straight forward, while red light is deflected toward the cavity walls where it is absorbed. Therefore, when observed directly ahead, the water level gauge shows red for air and green for liquid, appearing clear and transparent.
The gauge manufacturer was careless and got it reversed.....
The filter was installed backwards; it has been reinstalled correctly