• Easy to service, high sensitivity, stability and accuracy
• Easy zero-point checking, even when visibility is poor
• A special sample flow concept entirely eliminates the danger of flow cell contamination
• Easy calibration check with checking rod, even at high dust levels
• Continuous monitoring of visibility using scattered light principle
• Dual-beam method
• Operation via local control unit or central multi-channel control unit
• Installation in tunnel tube or niche
• Optional sample heater: Choice of measurement with/without fog compensation

The VisGuard measures the scattered light intensity of a sample drawn into the instrument. Filtered purge air is fed through the flow cell, thus enveloping the sample in a protective shroud of clean air. This effectively keeps the optics clean. Installations are either in the tunnel cavity/niches (in-situ) respectively using extractive sampling away from the cavity. An optional sample heater eliminates the influence of any mist effects.