Valmet extends its quality control systems expertise to the paper and board machine forming section with the introduction of the Valmet IQ Dryness Measurement (IQ Dryness). Utilizing microwave technology, the IQ Dryness measures the water layer thickness on the web, which can be used to calculate the web dry content. As well as removing most of the water, the majority of paper properties are also developed in the forming section. The inclusion of IQ Dryness in Valmet's paper quality control family opens new possibilities as it helps to close the information gap between the stock approach system and dry end quality sensors.
"Perhaps the biggest effect is the better management of dewatering. This has a great influence on the amount of the subsequent drying energy needed with potentially big cost savings in paper production. An increase of just 1% in dryness before the dryer can reduce the amount of energy needed to evaporate the excess water by approximately 4%," says Marko Toskala, Director, Quality Management Solutions, Valmet.
Unlike other measurement technologies, Valmet IQ Dryness is not sensitive to conductivity which makes it suitable for use with all grades of paper and board. As well as energy savings with vacuum optimization; quicker startups, faster grade changes, fewer breaks and improved break recovery are just a few of the benefits that continuous measurement of water removal makes possible.
Optimized dewatering not only improves bonding for multilayer board machines but can also reduce the problems of blow induced breaks caused by excess moisture in the middle layer entering the drying section. Additionally, the measurement facilitates the online monitoring fabric condition together with improved troubleshooting of pulsation, vibration and other quality destroying wet end problems. The sensor's small size enables measurement in places inaccessible earlier.
This new sensor joins the Valmet IQ family of single point and scanning measurements to provide papermakers with a complete picture of MD and CD moisture from the forming and press sections, dryer and size press right up to the reel. Together with sophisticated moisture controls and an extensive range of actuators to control moisture levels and profiles, Valmet can close the loop to offer improved efficiency and runnability as well as better paper quality and printing properties.
