The Valmet IQ Pulp Weight Measurement (IQ Pulp Weight) provides a strong, reliable foundation for MD and CD basis weight controls in heavy board or pulp machines. Digital signal processing, internal calibration verification and temperature compensation ensure superior accuracy even in hot, humid and dirty process environments.
Beta radiation provided by an enriched Sr90 nuclear source of the Valmet IQ Pulp Weight is absorbed by the mass in a paper or board sheet. As mass increases, the transmitted radiation captured by the detector is reduced.
This basic nuclear measurement principle is taken to a new level with special design techniques and measurement diagnostics. This enables the Valmet IQ Pulp Weight to provide the stable, high-resolution measurements needed for precise MD and CD controls.
The digital measurement resolution of IQ Pulp Weight is automatically optimized for specific grades by using internal calibration verification standards, custom selected for the required range of measurements. The internal standards also compensate for any dirt buildup and source decay through scheduled standardization sequences.
In addition to internal temperature stabilization, the temperature of the source and the detector head air gaps is actively regulated. All internal and external air gap temperatures are measured, and the effect of air density changes is automatically incorporated into the temperature compensation algorithm.