MODULE JET, THE NEW HEADBOX DESIGN WITH C ONSISTENY-CROSSPROFILE CONTROL

Growing pressure of competition in the markets for paper, and steadily rising demands concerning the quality of paper web, necessitate the u se of headboxes which enable adjustments of important paper qualities to be made over narrowly limited local sections of the web. Presently used headboxes have the disadvantage that the substance cross profile cannot be influenced independently of the profile of fibre orientation . In consequence of the necessary adjustments to correct the substance , a paper web is produced which has non-uniform fibre orientation, and this can result in cross-tensions and poor lying-flat of the sheet. T his mutual dependency arises because the same mechanism is employed to alter both cross profiles; this mechanism being cross-flows in the sl ice. Now, for the first time, it will be possible to alter the substan ce and the fibre orientation profiles deliberately and over a wide ran ge. This is made possible by the Module Jet headbox, which allows sect ional consistency and flow-quantity adjustments. The width of the indi vidual sections, which give separate control of substance and fibre or ientation, can thereby be reduced to 50 mm.