The Steam-Trac STB-3000 Bi-Color Ported Gauge must be used with a red/green filter illuminator. The gauge chamber is constructed with opposing ports at an angle so that red light will pass unimpeded through the gauge in the steam phase. When water is present, refraction will allow green light, only, to pass through. The result is a clear visual indication of water level.
All connections and materials fully comply with ASME requirements, and the gauge may be used as a Direct Reading Sight Glass for compliance to ASME PG-60. Since water appears completely different than steam, it is not necessary to have overlapping sections. Multiple section gauges will have a continuous chamber constructed of a single piece of bar.
An Illuminator is required for this gauge to work properly.