The Valmet IQ Basis Weight Measurement (IQ Basis Weight) provides accurate scan averages and high-resolution CD profiles of basis weight. Digital processing, internal 7-point calibration and sensitive temperature compensation ensure measurement accuracy even in harshest environments.
The Valmet IQ Basis Weight Measurement uses Beta radiation from an enriched Kr85 nuclear source to measure dry end basis weight. The radiation is absorbed by the mass in a tissue, paper or board sheet. As mass increases, transmitted radiation that is captured by the detector is reduced.
Employing special sensor design techniques and diagnostics, the IQ Basis Weight refines this basic absorption principle to provide stable, high-resolution online data for precise MD and CD controls.
The digital measurement resolution of IQ Basis Weight is automatically optimized for specific grades by using seven internal calibration verification standards. The internal standards also compensate for any dirt buildup and source decay on the sensor’s windows during scheduled calibration sequences.
The calibration of IQ Basis Weight is consistent from grade to grade despite changes in sheet filler content or coating weights. In addition to internal temperature stabilization, the temperature of the source head air gap is controlled. The detector head air gap is also actively regulated.