Recent Results of a Gamma Sensor in a Paper Machine Forming Section, 2000 Papermakers Conference Proceedings

Harry K. Heise--The Portable Gamma sensor has been used for many years on the paper machine to determine machine direction drainage profiles, the efficiency of wet-end dewatering elements and to define numerous characteristics of paper machine clothing. Monitoring and controlling paper machine operating parameters have become increasingly more sophisticated over the last few years and mill management and operating personnel now question the costs of not having a reliable measurement and information directly in the forming section. This has led to the more recent application of the sensor permanently mounted in fixed locations in the forming section to determine and control consistency and quantify the dry-line position. The most recent evolution of the sensors has been to traverse them on a forming wire in a continuous CD scan. Users report the numerous benefits such as knowing the actual shape of the profile in the forming section, determining and setting the sheet edges, diagnosing and correcting quality problems, upsets and grade changes. Typical scans are displayed with profiles showing the average consistency and basis weight. This paper attempts to provide an overview of the numerous technical applications of the sensor and to report the most recent results from a scanning sensor in the paper machine forming section. Key Words Gamma sensor, forming section, wet end measurements, scanning