Voith WebDetect-nx protects against machine damage

Heidenheim, Germany-based Voith says its WebDetect-nx identifies paper web breaks in a reliable and fail-safe manner. It uses a measuring process in which a multi-light sensor measures different light sources in the visible and IR light frequency range and interprets the measurements simultaneously at high speed.

This prevents potential impairment of the measured result to allow reliable detection of faults resulting in fewer false positives, less production downtime and less risk of machine damage from undetected breaks.

WebDetect-nx solves the typical problems associated with previous web break detectors based on IR light and standard sensors. For example, if the contrast between paper web and dryer fabric or basis weight is too low or the moisture content of the paper too high, older methods tend to trigger false positives. This leads to production downtime or even damage to the paper machine.

Voith says WebDetect-nx prevents false positives through more precise identification of web breaks based on a measuring principle in which light beams of varying wavelengths are projected onto the web simultaneously. The spectroscopic process takes account of the special optical characteristics of the paper web and dryer fabric. The system measures the reflectivity and processes the measurement using a microchip. It also compensates for extraneous light effects, filters the signal, accurately calculates trigger thresholds and adjusts them continuously. Thanks to the chip-supported processing, the measuring signal is more accurate which leads to fewer breaks and the downtimes associated with them.

WebDetect-nx features interfaces like Profibus, Modbus-TCP or Standard I/O for simple access via the PC system on which measuring processes can be visualized and the break sensors controlled interactively. Using PLC function modules, WebDetect-nx can be easily integrated into the machine control system for fully automatic operation.

The technology is one of Voith’s innovations from its Papermaking 4.0 concept that allows papermakers to move towards the Smart Factory. During start-up, customers can set specific parameters via the user interface. Only the sensor measuring head requires mechanical adjustment.

An improved purging air system keeps the sensor optics cleaner longer; they rarely need maintenance. The diagnostic system automatically notifies the need for maintenance.

Voith offers WebDetect-nx as a complete package and takes care of system integration, engineering and documentation of all hardware and software components, and commissions the system.

Voith Paper, www.voith.com

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