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

The vacuum roll on the paper machine is mainly dehydrated by vacuum suction. Its advantages are convenient operation, high dehydration rate, less wear of the net, and convenient paper threading. The use of vacuum rolls in the paper machine can increase the dryness of the wet paper to more than 20%

The cage is the main component on which the paper web is formed in the cylinder paper machine. It is required to filter water evenly and not produce excessive agitation in the mesh tank when rotating. The cage should have sufficient rigidity and accurate geometric dimensions

The net trough structure of the cylinder paper machine is usually made of wood, and the main part of the trough ring is sometimes lined with metal (usually stainless steel), and sometimes also made of plastic. The so-called mesh groove ring refers to the annular gap between the surface of the mesh cage and the semicircular body.

The sandwich former in the paper machine represents a type of former in which the headbox jet is sprayed between two converging meshes.1. The paper web formed on the ordinary Fourdrinier wire or round wire is not uniform in the thickness direction