Causes of forming fabric arching White water continuously flows to a single point on the inner side of the forming fabric. Remove accumulated fibers and take proper measures to eliminate factors causing white water tray overflow. Pulp deposits on breast roll, press roll and turn roll, which are formed as water flows around the rolls. Check the alignment of breast roll, couch roll and turn roll through the seam line and running track of the forming fabric. Remove burrs on all rolls including table rolls. Clean the holes of the couch roll before installing the forming fabric. Replace worn dewatering elements and turn rolls. Adjust the tension of the forming fabric with tension rolls and stabilize tension fluctuation. Consider installing spreader rolls on the fabric return path. Repair or replace worn and deformed vacuum boxes. Reduce vacuum degree to avoid suction and dragging of the forming fabric. Internal arching is mainly caused by pulp deposits on internal breast rolls, turn rolls, couch rolls an

The main spare parts of the dryer section are dry fabrics and felt ropes. Damage and premature removal of dry fabrics are mostly caused by external and operational factors. Common faults include holes, edge cracking, local creasing, fabric wandering, and squeeze breakage. Except for unexpected and unavoidable failures, most of these problems can be prevented by careful and standardized operation.

Adaptability of Hydraulic Headboxes Hydraulic headboxes were developed alongside high-speed twin-wire paper machines. Owing to the short forming surface of twin-wire formers — in other words, the extremely short forming time of the paper web — the web is essentially "set" once the stock jet impinges on the wire. Therefore, the stock must be uniformly distributed within the headbox. High-efficiency, compact, laterally uniform single-inlet tapered headers and fixed homogenizing devices are commonly adopted. High-velocity stock flow generates intense micro-turbulence through cross-sectional or geometric changes of fixed elements, dispersing the stock suspension. With stable longitudinal flow and no cross currents inside a hydraulic headbox, the basis weight profile of the sheet can be adjusted by regulating the stock concentration of the header tubes, achieving better results than locally modifying the lip opening with 微调 rods. This is an advantage unattainable by roll-type headboxes. The jet velocity of a hydra

In paper production, the headbox is one of the most critical pieces of equipment that determines the quality of the paper’s fiber structure. It is responsible for achieving uniformity and controllability of paper properties. It directly affects the paper’s MD/CD strength ratio, tensile or breaking length, porosity, formation, and retention. The future development goals of papermaking — including continuous improvements in machine speed, efficiency, and paper quality — impose a series of requirements for the upgrading of existing headboxes. The operating performance of a headbox is closely related to paper machine speed and efficiency. At the same time, improvements in headbox performance should also be considered in combination with the quality of the paper’s fiber structure (uniformity of basis weight distribution and fiber orientation). Higher demands must also be placed on mechanical manufacturing under high-speed conditions. The development of headboxes has been driven by the continuous increase in paper