Protagon Process Technologies GmbH (P2T)

Sensors for Basis Weight Measuremen

Well proven radioactive nucleids (beta-transmitters), installed in an electric-pneumatic holder, are used as an energy source. A high-quality ionisation chamber is applied as receiver for each beta-radiator. The output current is proportional to the absorbtion of the web material. Software algorithms in the computer convert the current to the basis weight (g/m2). Four levels of air temperature in measurement gap are compensated for by software algorithm as well.

Type	Measuring range	Resolution	Accuracy
Basis weight beta-transmission PM147-source	10 up to 100 g/m2	0,01 g/m2	0,15 g/m2 or 0,15 %
Basis weight beta-transmission KR85-source	50 up to 1000 g/m2	0,1 g/m2	0,3 g/m2 or 0,25 %
Basis weight beta-transmission SR90-source	300 up to 5000 g/m2	0,5 g/m2	1 g/m2 or 0,25 %

Ash- / filler Measurement

Depending on specific tasks the radioactive nucleid FE55 or an x-ray beam is used as an energy source for radiating through the web for filler- or ash measurement.
Computer analysis of the absorbtion determines the component of the different web material. Effective coat-weight measurement can be realized by calculating the difference between the two measuring stages

Type	Measuring range	Resolution	Accuracy
Ash measurement through FE55 or x-ray	10 up to 5000 g/m2	0,01 % or 0,01 g/m2	0,2 g/m2 or 0,25 %

Moisture Sensors

Optical multi wavelength analysis methods in the infrared range are used for moisture measurement on light weight products, wich supply stable measurement values, nearly independent of ash content and material property. Comparing the absorbtion at characteristics wave lenghts yields the measurement values. PROTAGON´s method is based on a real single spot sensor.
For webs of higher moisture content and/or higher basis weight sensors of the leading manufacturer Scanpro, working on the basis of mocrowave principles, are applied.

Type	Measuring range	Resolution	Accuracy
Moisture measurement through infrared-transmission	up to 30 % H2O up to 300 g/m2	0,01 % H2O abs.	0,1 % H2O abs.
Moisture measurement through microwave resonance	up to 600 g/m2 H2O	0,2 g/m2 H2O	0,5 g/m2 H2O
Moisture measurement through microwave resonance	up to 1500 g/m2 H2O	0,5 g/m2 H2O	1 g/m2 H2O

Thickness measurement

Contacting thickness measurement

Thickness measurement on light weight products, also with porous surface strcture, is imitated by the well proved laboratory thickness measurement. The web is guided by air-cussions of defined distance to the web. An opposite scanning unit is also sliding over the web on a guided air-cussion. The distance of the two gliders is performed online with an integrated sensor system and the thickness of the web is estimated additionally.

non contacting thickness measurement

The distance between an upper and a lower sensor to the web surface is measured by laser sensor using the triangulation principle. The distance of the two measuring sensors which is not linear in practise, is permanently measured by a sensor, working on the basis of the eddy current principle. The resulting thickness measurement value of the web is determined by the basis distance of the two sensors, deducting the sensors to the web material.

Type	Measuring range	Resolution	Accuracy
Thickness measurement over guided air-cussion	15 up to 600 µm	0,2 µm	0,6 µm
Thickness measurement over non contacting triangulation	20/100 up to 5000 µm	0,2 µm	0,25 % or 1 µm

High-Precision-Scanners

The PROTAGON high-precision scanners consist of substantially made weldments, equiped with highly-effective mechanical, electrical and electronic components. Thus high precise scanning of the two sensorhalfs is also possible for all environmental conditions and guarantees long durability.
Two scanner types are available for different ranges of application, delivered as single or double side type, depending on the insertion of the two sensors.
Highly effective pneumatic controlled c-frames are available for measurement tasks where a traversing system is not needed.