| 摘要 |
The invention relates to a method and a system for regulating the head box. In the method a flow Q4.1, Q4.2 ... Q4.n is introduced into the pulp suspension M at different points over the width of the head box, the concentration of which flow can be regulated. In regulating the concentration of the said flow Q4.1, Q4.2 ... that is fed to the pulp suspension M, two secondary flows are combined by introducing an additional flow Q1.1, Q1.2 ... Q1.n into the pulp suspension flow Q3.1, Q3.2 ... Q3.n. The mixing ratio in the said combined flow is regulated by regulating the said additional flow Q1.1, Q1.2 ... Q1.n; by reducing or increasing the restriction of the said additional flow by means of a valve 21a1, 21a2 ... 21an. In the method a part of the combined flow Q1.1 + Q3.1 + Q3.2 is allowed to overflow after the point for the combination of the additional flow Q1.1, Q1.2... and the pulp suspension flow Q3.1, Q3.2... and to flow away, and the remainder is fed as a stream Q4.1, Q4.2... to the pulp suspension M of the head box, so that, for example, as the total flow Q1 + Q3 increases when the flow Q1 increases, the excess is removed, that is to say the flow Q2, as an overflow, and the flow Q4 to the discharge channel are kept constant. <IMAGE>
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