In the paper mill, we all hope that the paper machine can keep stable operation, which is just a good wish, in fact, paper machines often appear a variety of problems. Then which links should be stabilized to make the normal operation of the machine? Here I share with you some good ideas.
Slurry ratio and beating quality should be stable. Stable slurry can maintain the stability of process parameters of the paper machine.
Sizing pressure stability determines the stability of the pulp speed ratio. The size of the pulp speed ratio determines the vertical and horizontal tensile force of the paper, the large fluctuation of the pulp speed ratio brings fluctuation of the dehydration rate of the net and different quality of the fiber; the fluctuation of paper unevenness and the vertical and horizontal tension will cause changes to stripping angle of the press section; the paper web tension changes in other parts can cause paper disease or broken paper.
Normally, the instantaneous fluctuation of the headbox pressure is required to be within 0.6 kPa. The main reason for the pressure fluctuation is the pressure stability of the sizing pump, the inherent pulse of the pump, the speed control quality of the pump, the pulse size of the mesh screen and the gas content of the slurry. In the pressure problem, the use of pressure sensor qith high precision and stable performance is essential, playing a key role in the normal operation of the paper machine and the quality of paper.
The stability of the slurry flow is also critical. The basic standard of the flow from headbox to the web pulp: the web point should be about 10cm away from the lower lip bar of the headbox, there is a small amount of dehydration before the forming board to seal the air; the blade of lip bar should be thin, to avoid interference with the surface of pulp layer to produce flying pulp. It is necessary to ensure that the slurry flow of the edge is regular and smooth, and water spray of the fixed edge is also essential.