Sensor for measuring thickness of paper and cardboard web on an air cushion A357 CAN

Sensor for measuring thickness of paper and cardboard web on an air cushion A357 CAN

Brief description

Among the many requirements to parameters of the paper web quality (and cardboard web also), in many cases one of the most important is the requirement of high precision and uniformity of thickness. These requirements can be implemented through a continuous technological control of leaf thickness in the MD and CD, and using this data for automatic control.

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  • While developing the paper web thickness sensor (cardboard web) it is necessary to consider tough enough conditions of its operation. The use of non-contact thickness measurement method in this respect has certain advantages over traditional methods.

    The operation of the thickness sensor "A357 CAN" is based on induction resonance method. The thickness sensor itself is an electromagnetic resonant circuit consisting of inductor and movable ferrite disc, which are placed on both sides of the paper web (cardboard web). Depending on the thickness of the paper web (cardboard web) the resonant frequency of the circuit is changing. The Inductor and ferrite disk, are contacting with the paper web, not directly but through the air cushion. This reduces the wear of the upper and lower sensor heads, where the inductor and ferrite disk are placed..   

    The sensor has mechanism of thermal compensation of frequency electromagnetic resonant circuit.

    Thickness gauge calibration is carried out using thickness etalons of lavsan. These standards are selected according to the desired range of thickness measuring. The zero point for calibration will be the frequency of the oscillator in the absence of paper web in the gap. The calculation of thickness is carried out using the polynomial formula.

    A357 CAN sensor has a wide range of working thicknesses (up to 700 microns) and adapted for use on high-speed paper machines.