Paper | Board | Tissue – Quality Control (Scanner) System

A Basis Weight Sensor – Beta Source”QCS measures the Basis weight (g/m²) which is the quality production parameter of the paper used by the operators to ensure that their production is always within the acceptable weight range. The measuring principle of Basis weight is based on the attenuation of Beta radiations emitted by a nuclear source as it passes through the paper/board. Basis Weight Sensor Specifications

• Beta Transmission Sensor 200mCi Kr85 Radioisotope (10-1000 g/m²)or 500 mCi Pm147 (10-200 g/m² ).

• Accuracy & Repeatability : ±0.15% or 0.15 GSM (whichever the greater)
• Sampling Time : 10msec
• Air Gap : 10mm
• Operating Temperature : 0-70^OC
• Ionization Chamber Detector
• Integrated signal conversion through 24 bit A/D converter with in-built digital filters
• Measuring Spot Size : 12mm
• Insensitive to paper formation

B Moisture Sensor – NIR / Microwave The next most important measurement in the paper industry is the Moisture measurement. This measurement enables the machine operators to keep the water content in the paper within acceptable limits and is especially useful for optimizing the production capacity.
Based on the GSM range, two types of Moisture sensors can be offered i.e. Near Infra-red (IR) or the Microwave radiation type.
NIR sensor is most suitable for fine paper and lighter paper grades. The measurement is based on the principle that when infrared light passes through or is reflected by a paper sheet, it is preferentially absorbed at very specific wavelengths by the water in the sheet more so than fiber or other sheet components.

The Microwave Moisture Sensor is most suitable where GSM of paper is higher than 150 GSM and bulk moisture measurement is required or where there is high carbon black content in paper. The sensor is commonly used for Craft and Duplex boards. The moisture content measurement is based on shift in resonant frequency of a cylindrical cavity by presence of a strong dielectric, like water.

Moisture Sensor Specifications
Near Infrared Transmission/Back-scatter Sensor

• Measurement Range : 0-15%
• Accuracy & Repeatability : +1%
• Measurement Spot Size : 20mm circular
• Operating Temperature   : 0-70^oC
• Sampling Time: 10msec.
• Insensitive to paper scattering by using special scattering optics
• Carbon black compensation

Microwave Sensor

• Insensitive to ink residues in recycled paper or color of the sheet
• Insensitive to surface structure or moisture stratification.
• Insensitive to fillers such as China clay or whiteners
• Sampling Frequency : 100 samples per second
• Measurement Range : up to 100 GSM of water
• Measuring gap : 10mm
• Measuring Area : Circular 50×50 mm
• Operating Temperature Celsius : 0-70^oC

C Ash Sensor – X-ray The Ash measurement is based on the absorption of X-ray radiations by the inorganic materials like Clay, Calcium Carbonate & Titanium Dioxide in the paper and as these contents vary during production the transmitted radiations that are captured by the ion chamber type detector also vary accordingly.
Ash Sensor Specifications

• X-Ray Transmission Sensor : 2W, 10KV (max)
• Measurement Range : 10 -400 GSM
• Accuracy & Repeatibility : ±0.4%
• Air Gap : 10mm
• Sampling Time : 10msec.
• Operating   Temp. : 0-70⁰C
• Ionization Chamber Detector
• Measurement Spot Size : 12mm

D Caliper Sensor The Caliper measurement principle is based on electromagnetic induction produced by two contact type components, an inductive coil housed inside a sapphire disk and the ferrite target laminated with an ultra thin sapphire wafer, mounted on the opposite bellows. As the thickness of the paper passing through these bellows change, the distance between them also changes, resulting in the change of coil inductance which is measured through a coupled oscillator circuit.
Caliper Sensor Specifications

• Measurement Range : 0.02 -1.00 mm
• Repeatability : 0.5µmicron
• Dynamic Correlation : 1.5µmicron
• Long term stability : 1.0µmicron
• Sampling Time : 10msec