Paper Machine Press Felt

The press section of paper machine, as an intermediate link between the wire section and the dryer section, plays a role in further removing free water inside the paper, surface finishing treatment, and providing sufficient wet paper web strength. In the entire process, apart from the mechanical part, the press felt, which directly contacts the paper web, plays an indispensable role.

Press Felt Base Layer

The base mesh layer, also known as the base fabric, is equivalent to the skeleton structure that makes up the press felt. It determines the upper limit of the felt's weight, breathability, moisture content, and shape stability. The base mesh is woven into a mesh structure using nylon material composed of combed threads, single threads, multiple threads, sandwich threads, etc. At the same time, the woven base mesh is divided into single layer base mesh, double layer base mesh, three layer base mesh, and composite base mesh.

Press Felt Batt Fiber Layer

The diameter of batt fibers directly affects the breathability, surface smoothness, pressure and dehydration transmission path of the press felt, and has a significant impact on the performance of the press felt. When it comes to batt layer, it mainly affects the fineness of the surface of the felt.

It is usually expressed by the dtex value of surface flocking. dtex refers to the weight of ten thousand meters of fiber corresponding to dtex, measured in grams per 10000 meters. The smaller the value, the finer the surface flocking, which can achieve a smoother paper surface effect. At the same time, using the same or different surface flocking dtex values for the top and bottom felt can effectively assist in the transfer of the paper web. Generally speaking, the paper is easy to adhere and transfer towards the direction of the felt with lower dtex values and finer surface.

In addition, flocking also affects the fiber density and internal space stability of the felt. When the batt density is too low, it is difficult for the inside of the felt to be quickly filled with moisture and reach saturation, the felt has a long adaptation period, and the paper machine speed cannot be started; When the batt layer density is too high, the felt is prone to being compacted and dirty, making it difficult to clean, resulting in rapid closure of the blanket and premature removal due to insufficient dewatering capacity.