Automated Gate Rejection Algorithms for Real Time Recycled Fiber Blend Variations
Real-time NIR spectroscopy coupled with automated divert gate algorithms stabilizes furnish quality, rejecting off-spec recycled stock before pulper entry.
Bale Moisture Attenuation
Absorption Differential
Electromagnetic signal loss across a compressed mass of recycled or virgin pulp fibre indicates the total water content present within the volume. Commercial bale moisture attenuation depends on the density of the packed material and the frequency of the microwave or radio signal passing through it. Calculation happens automatically.
Dielectric Measurement
Measuring the drop in energy as it travels through the bale provides a non-destructive method for verifying the air-dry weight of the raw material. Automated sensors calculate bale moisture attenuation by emitting a known signal strength from one side of a conveyor and measuring the residual strength on the opposing side. High water levels absorb or scatter more energy.
Calibration adjusts for the presence of metallic contaminants or heavy plastic inclusions that might otherwise skew the results. Consistency in the packing density ensures that the signal remains representative of the entire load.
Acceptance Threshold
Accuracy in this calculation prevents a paper mill from paying for water at the price of fibre. Standardized bale moisture attenuation readings allow for immediate rejection of lots exceeding a moisture limit or for the calculation of price adjustments based on the actual dry mass delivered. The process stops being effective when internal bale temperatures vary wildly or when the material is frozen.
Frozen water changes the dielectric constant of the mass and produces an unreliable signal.