Gapformer
A further development in modern, high-speed paper machines are the so-called gap formers. In these formers, drainage is carried out to both sides simultaneously as the suspension is injected directly between the two wires directly from the headbox. Upon leaving the headbox, the pulp mass is immobilised in a matter of milliseconds, thus preventing later drainage elements from affecting the sheet structure which is now beginning to form. The fibre web is frozen – literally – the second it comes out of the headbox.
This process sets high demands on the quality of the head- box and the constant part.