Headbox paper machine, the basic knowledge those papermakers need to know

Headbox is known as the "heart" of the paper machine. It is the key component of the paper machine, the hub connecting the two parts of the "flow" and the "forming", and it is also one of the fast-developing parts of the paper machine. In papermaking, the function of the headbox is to send the required pulp to the forming wire in accordance with the requirements of the forming part of the paper machine, providing the necessary prerequisites for the good forming of the paper web.

The role and performance of Headbox

       As the combination of "flow" and "forming" of the paper machine, the basic task of the headbox is to provide good preconditions for paper sheet forming, that is, to evenly distribute the paper material along the width of the paper machine to ensure uniform pressure distribution, Speed uniformity, flow uniformity, concentration uniformity, and fiber orientation controllability and uniformity; effectively disperse pulp fibers, prevent fiber flocculation, and provide and maintain a stable sizing head and pulp-to-net speed ratio according to process requirements.

During the long-term development of pulping and papermaking technology, despite the appearance of various structural forms of Headbox, its main functions are basically unchanged, namely, slurry distribution, homogenization and shotcreting.

The basic functions of Headbox can be described in 5 aspects:

(1) Provide a uniform and stable sprayed slurry flow to the entire width of the paper machine, avoiding transverse slurry flow, non-directional tributary flow or longitudinal stream;

(2) Provide a stable lip with a geometric size that meets the requirements, and is not affected by temperature, pressure and lip opening;

(3) Form a fiber suspension with less flocculation and good dispersion;

(4) Provide a control of quantitative distribution, falling point, shotcrete angle and shotcrete speed that can meet the technological requirements;

(5) Provide convenient measures to keep the Headbox clean, easy to operate and maintain.