ONLINE MEASUREMENT OF COAT PAPER QUALITY PARAMETERS USING INFRARED SENSORS

摘要

Measurement of process quality parameters is very important for control and optimization in any process industry. Many important process parameters like moisture, temperature etc. are measured through IR based sensing. In a paper coating process, pigment coat is applied to the stock paper and dried to get superior surfaced enhanced grade paper for better printability. Coat weight and coat moisture are the two important quality parameters of this process required to be measured for their control and to meet the specifications of the coat paper being manufactured. Two non-contact IR based sensors that work on absorption principle had been tried to measure these process parameters, in real time and online during the coat paper manufacture. These sensors were attached to two independent scanner frames so that sensors would move across the width of the paper to monitor these parameters. These frames are located at the strategic locations of the process manufacture to get direct dry coat weight and coat moisture values irrespective of the basis weight of the base paper. The scanner frames and sensors are connected to a developed electronic system to control the scanning operations and data acquisition. The sensors are so calibrated that they work for the entire production range (18 to 23 gsm coat weights) of the mill. The values obtained from these sensors were compared with lab values. The system had been successfully installed and commissioned in a full-fledged paper-coating mill in western India. This paper gives the performance details of the sensors.