Views: 22 Author: Site Editor Publish Time: 2021-08-14 Origin: Site
The earliest used headbox paper machine was an open headbox with a pulping gate, which was produced in 1804 before the Fourdrinier brothers invented the Fourdrinier paper machine. Its structure and form are relatively simple, the technical requirements are not high, it can only be applied to low-speed paper machines, and the homogenization effect is poor.
As the speed of the paper machine increases, the static head required for the formation of the paper material in the weir must increase with the square of the speed. Therefore, when the speed of the paper machine increases, the required static head must increase. At higher speeds, if an open headbox is used, its volume, height, structure, and weight will become very large and more complicated. Moreover, it is impossible to efficiently distribute, rectify and disperse fibers for such a large volume of paper in the weir pool to provide a high-quality online jet paper stream. In order to solve this problem, a closed (air cushion) headbox was researched and developed in the late 1940s.
After the 1970s, the air cushion headbox paper machine developed and developed has absorbed some of the advantages of the headbox design, and adopted some new headbox technologies such as cone-shaped slurry manifolds, hydraulic slurry rectifying elements, elimination of foam overflow, and optimization of the upper and lower headboxes. The lip structure has been greatly improved in performance, so it is also widely used in medium-speed Fourdrinier paper machines and sandwich paper machines.
Since the 1970s, in order to meet the needs of the development of new multilayer forming technology, a multilayer hydraulic headbox paper machine has been researched and developed. Multi-layer hydraulic headbox is a full-flow hydraulic headbox with multiple channels. At present, the multi-layer hydraulic headbox can not only be used for the production of cardboard, but also can be used for the production of tissue paper and paper. It plays a very good role in improving the quality of paper and the rational use of fiber raw materials. Therefore, the multi-layer hydraulic flow The headbox has a good development prospect. At present, multi-layer hydraulic headboxes of various structures have been researched and developed.
Since the 1990s, in the common technology of headbox paper machine, the research and development of headbox dilution water concentration control and adjustment technology is a major achievement and progress. The headbox adopts the dilution water concentration control and adjustment technology, and the problems such as drift and cross flow caused by the adjustment of the weir plate. Several systems have been developed, and most of the newly designed headboxes use this technology.
It can be seen from the development history of the above headbox paper machine that the main goal and driving force of the headbox development is to make the headbox adapt to the increased speed of the paper machine and produce better products. Each headbox paper machine has a range of operating speed and a range of product varieties and quality.