Dryer clothes or dryer fabrics or felts have an important role in the dryer section. Synthetic dryer cloth or fabrics are also considered as conveyor belts.
When the paper web exceeds the press section of the paper machine, more than half of its weight is water. Most of the water in the paper web should be removed in the dryer section of the paper machine to ensure a final moisture content of 4 to 6 percent. The dryer section is one of the most energy-intensive components of the paper machine (about 60%). Therefore, the role of the dryer or screen is absolutely enormous.
The dryer fabric presses the paper web against the surface of the steam-heated drying cylinder. As a result, the temperature of the web rises and water evaporates into and through the porous dryer screen. In addition, the dryer fabric helps support the paper web as it moves from one drum to another. The dryer screen controls the web shrinkage.
Dryer screen can be classified according to weave, category and combination method. Synthetic polyester dryer screen can be classified as one layer, one and a half layer, double layer, etc. according to the category. According to the weaving method, synthetic polyester dryer screen can be classified into 3 shuttle mouth, 4 shuttle mouth, etc. And as far as the combination method is concerned, the dryer can be divided into insert, pin, pin ring and spiral ring connection.
Selection: The choice of dryer screen or felt depends on various paper machine parameters such as paper grade, dryer configuration, dryer temperature, air balance in the hood, etc. The design and material of the dryer screen is also very important.
For a specific paper machine; the dryer permeability, design and material should be adjusted to ensure optimal drying from the drying zone. The breathability of the dryer fabrics or felt has a significant impact on the rate of evaporation of moisture. If the permeability decreases, the dryer fabrics is less capable of drying. Dryer screens with permeability in the range of 700-1000 cfm are used on paper machines to produce higher gsm kraft and paperboard grades. On the other hand 200-400 cfm dryer fabrics are widely used on medium to high-speed paper machines and below medium to high-speed paper machines on low-speed machines. A large contact area with the drying surface ensures uniform drying. Correct selection of dryers improves paper machine operation, increases drying speed, improves paper quality and saves energy.
In addition, the dryer fabrics or felt should have the following parameters or characteristics: aerodynamic properties, heat transfer, fabric tension, sheet support, thickness, heat resistance, moisture resistance, elongation by heat should be low, durability, silent drive, easy handling, etc.
