Doctor blades are used in various sections of the paper machine. In particular, the doctor blade plays a crucial role in the area of the center press roll, where in the event of a web break the paper is severed by the doctor blade underneath and removed. In the process, the doctor blade cleans paper residues off the roll cover, so that production can continue smoothly. To achieve this, a uniform contact pressure of the doctor blades over the entire width of the roll cover is critical.
If a paper manufacturer discovers problems, the triggers can be identified by Voith’s SensorBlade measurement and rectified based on the measuring results. The Voith SkyLine blade doctor blade used for the measurement consists of several segments that can be connected with one another and that are then fitted with sensors. As a result of this configuration, the measuring device is suitable for all machine widths. The readings from the individual sensors are condensed to provide an overview of the contact pressure over the entire roll width. The data is analyzed by Voith experts and summarized in the form of a report. These results allow the necessary optimization measures to be determined. The SensorBlade measurement can only be performed during a shutdown.
For example, one possible optimization measure is to readjust the blade holder. In severe cases the complete doctor blade unit, including holder and motor, has to be replaced. Voith can offer a solution to this by providing the entire necessary spare and wear parts.
Voith’s SensorBlade measurement is a special service that has already impressed several paper manufacturers. “We had problems with strong paper jams on the last drying cylinder of the coater, which led to increased machine losses. Through SensorBlade measurements, we were able to detect deviations in the blade contact pressure across the machine width and initiate targeted countermeasures”, say Werner Krobath, Head of Coating & Pulping Process at Norske Skog Bruck PM4 and Wolfgang Leichtfried, Head of PM4.