Causes and solutions of wet paper rewetting

Reasons for wet paper rewetting:

First, the wet paper sheet and the press felt are pressed. After the wet paper sheet is pressed, it cannot be separated from the press felt in time, and it stays on the surface of the felt for too long, which is the key to causing the paper sheet to rewetting.

The second is the layer design and structure proportion of the press felt. Generally speaking, the surface layer of the press felt uses fine denier fibers, the middle layer uses medium coarse denier fibers, and the bottom layer uses the coarsest denier fibers. Moreover, the finer the surface fiber, the larger and denser the layer, the greater the resistance of the moisture in the felt to rewetting, and the smaller the probability of moisture rewetting.

Thirdly, the dryness of the wet paper sheet in the inlet area and the moisture content of the felt are also important factors that determine the dryness of the wet paper sheet in the outlet area. According to the research and test, the greater the dryness of the wet paper sheet in the inlet area, the greater the dryness of the wet paper sheet in the outlet area. Under the condition of increasing the speed of the paper machine, in order to keep the same amount of water from the wet paper sheet, it is necessary to increase the line pressure of the press, and the felt with high water content in the nip. As the fluid pressure in the nip increases, the ability of the felt to absorb the water from the nip decreases, and there is a tendency to increase the embossing of the wet paper sheet.

Methods to reduce and eliminate wet paper rewetting:

From the above reason analysis, we know that the structural state of the press felt is very important to reduce and eliminate the rewetting. After the paper leaves the press area, it quickly separates from the felt, which is very helpful to reduce and eliminate the rewetting of the wet paper. At the same time, reducing the moisture content of the wet paper and the felt before the press is very helpful to improve the drying degree of the wet paper.