Crescent former headbox
The crescent former hydraulic headbox is used on tissue machines up to 2000 m/min production speed. All the structures are extremely robust so that the deflections are limited even at high pressures. A conical header distributes uniformly the pulp to a three stages step diffuser that is the most technological component because induces to the pulp the micro-turbulences necessary for the fiber mixing and the defloculation effect.
After the step diffuser the pulp is accelerated in the nozzle until the exit of the headbox were the special geometry of the bottom lip plus the fine adjustment of the top lip allow to obtain a very good basis weight profile. In order to increase the fiber mixing our headboxes can be equipped with optional blades that are installed in the nozzle. In order to correct the jet angle and the impingement point the headbox is positioned on two side pivoting supports complete of screw-jacks.
All the surfaces in contact with the stock are mirror polished with finishing grade of 0,2 µm. A complete set of splash guards protect the headbox against the dirty accumulation from the fog. Crescent former hydraulic headboxes can also be made in the double layer configuration.