A VEGA Regional Manager and Contro Valve, the shingle company’s local VEGA representative, took a look at the coating process and recommended the VEGAPULS 64 through-air radar sensor. The VEGAPULS 64 has a large dynamic range, so it is sensitive enough to measure liquids of any dielectric, and it is also intelligent enough to ignore false signals created by buildup, which, six months after installation, appears to be swallowing the antenna. Another advantage of a through-air radar sensor in this application is non-contact operation. Asphalt would have gummed up a mechanical level instrument, causing frequent maintenance and increasing the likelihood of instrument failure.
VEGA and Contro Valve assisted plant personnel in installing a VEGAPULS 64 approximately two feet above the asphalt coating tray. A sensor with a 1.5” NPT process connection was used because it offered the best microwave beam angle for the cramped application. An 80 GHz radar device, the VEGAPULS 64 can emit a beam as narrow as 3°. Such focusing is important in applications where microwaves have a tight path to travel to the product surface.