The wet suction box on the paper machine is a low vacuum dewatering element with a vacuum degree of 0.2-1kPa. The box surface is composed of multiple chopping boards, and there are also open-hole panels. The opening rate is more than 50%. The material is the same as the chopping board.

The top roll of the paper machine is the last dewatering device in the Fourdrinier section. After the wet paper web passes through the vacuum suction box, it is further dehydrated on the flat roll to reach a certain degree of dryness and has sufficient wet strength to be smoothly peeled from the surface of the forming wire and transferred to the press section.

The commonly used vacuum rolls on paper machines are single-vacuum chambers, but there are also double-chambers and three-chambers.The vacuum degree of the vacuum roller can be used in the range of 46-74kPa. When the top roller covered with a soft rubber layer is installed on the vacuum cover roller