In collaboration with the research and service institute Papiertechnische Stiftung (PTS) Heidenau in Germany, Voith is introducing a new measuring method to detect unwanted tacky contaminants known as stickies. The measuring method, which uses a near-infrared (NIR) camera, allows the reliable detection of contaminants along the papermaking process and offers higher measuring accuracy and a wider range of applications compared to conventional methods. The associated technical rule was recently published as DIN SPEC 6745.
Compared to established methods in the paper industry, the measuring technology uses NIR to determine more comprehensive information about the contaminants with a high measuring accuracy. The spectral measurements obtained are compared and assigned to values of known contaminants. This allows further classification of the contaminants based on their chemical composition. In addition, both adhesive and non-tacky contaminants can be identified and classified using the NIR measuring technology.
The new measuring method enables much more reliable information to be obtained while reducing the amount of laboratory work involved. “Using NIR technology to measure stickies allows the papermaker to determine sticky balances with reliable and sufficient accuracy based on single measurements,” says Dr. Linus Friedrich, Senior Manager R&D Fiber Systems at Voith Paper. “This demonstrates one of the benefits of the new measurement technology. With conventional methods, this was only possible to a limited extent due to the large variation in results,” Friedrich said.
Since the new measuring method uses laboratory sheets that can be produced by a laboratory sheet former and contain fibers, stickies and nontacky contaminants, numerous intermediate steps in sample preparation are eliminated. For example, the sticky contaminants in a stock sample no longer need to be concentrated in order to be analyzed. The preparation time for laboratory sheet formation is significantly shorter and the measurement is less prone to error than applying conventional methods. Moreover, the new NIR measuring method can be used to evaluate final paper samples in addition to stock samples.
Thanks to its technological advantages, the NIR measuring technology has the potential to replace established methods for measuring stickies. The publication of a technical rule on sample preparation and the performance of measurements has created the underlying conditions for setting a new standard in the paper industry.
The new measuring technology is available at the Voith Paper Technology Center in Heidenheim for the technology group’s R&D activities and for customer trials.