What is Paper Machine Dryer Fabric ?

Paper Machine Dryer Fabric

The dryer fabric plays a pivotal role in the drying zone of the papermaking process, where it is primarily deployed. Its core function lies in tightly wrapping or carrying the paper, especially in the wet paper web state, ensuring its smooth transfer. Furthermore, the dryer fabric, with its flat and fine mesh design, provides excellent surface smoothness for the paper. Simultaneously, it possesses appropriate breathability to accommodate the moisture evaporation needs of paper webs at different locations. More importantly, the dryer fabric can withstand harsh conditions such as high temperatures, high humidity, and extreme acid-base environments in the dryer section, ensuring the stable operation of the papermaking process.

Spiral Dryer Fabric

The spiral dryer fabric, as an important type, plays an indispensable role in the field of paper production with its unique design and superior performance. The spiral dryer fabric stands out in paper production due to its dirt resistance, nearly seamless design, excellent wear resistance, and convenient cleaning characteristics. However, it also has certain side effects, namely, the paper surface may have slightly visible marks. In addition, the use of dryer fabric made of different materials can also have a certain impact on the usage effect.

Flat Yarn and Round Yarn Dryer Fabric

In paper production, the most commonly used material for the main body of the dryer fabric is polyester. According to the weaving and manufacturing method of the dryer fabric, polyester can be divided into round-yarn polyester and flat-yarn polyester. However, in daily use, flat-yarn polyester often exhibits better performance. This is attributed to its flat yarn structure, which provides a wider paper contact surface, thereby reducing the occurrence of dryer fabric marks. At the same time, due to the geometric differences between flat and round wires, flat wires also demonstrate superiority in controlling the accumulation of adhesive contaminants.

In the early days, dryer fabric typically employed a design featuring round warp threads and round weft threads. However, with technological advancements, standard dryer fabric have gradually evolved to utilize flat warp threads paired with round weft threads. There are even some advanced dryer fabric that fully adopt a flat yarn design. Through comparison, it becomes evident that the application of flat yarn significantly reduces the accommodation space for adhesive substances within it.

In addition to avoiding wire contamination through the design of wire geometry, reducing the adhesion of adhesive substances is also an important means of anti-pollution. This can be achieved by adding fluorine-based substances to polyester materials, thereby reducing the surface energy of the material and making it difficult for contaminants to adhere to it. In this way, a series of problems caused by wire contamination, such as adhesive black particles, insufficient drying capacity, uneven moisture distribution across the paper machine, and paper defects such as black spots, can be effectively controlled.

Hydrolysis Resistance of Dryer Fabric

Due to the fact that the dryer fabric typically operates within a closed hood, facing harsh conditions of high temperature and humidity, coupled with the non-neutral pH of some base paper, polyester materials are prone to corrosion. The hydrolysis issue of the dryer fabric is often not caused by wear (unlike the forming fabric‍ and press felt, the dryer fabric is mainly affected by rolling friction), but rather by dirt or corrosion. To extend the service life of the dryer fabric, anti-hydrolysis agents are often added to the threads. However, it should be noted that anti-hydrolysis agents are prone to volatilization and precipitation in environments at or above 160°C. Due to their toxicity, special caution is required when producing food-grade paper and paperboard (the temperature of the hood and dryer cylinder usually cannot reach this level).

PPS Enhanced Edge Design of Dryer Fabric

The edges of the dryer fabric are frequently impacted by the correction fingers during production. If the weaving quality is poor or hydrolysis occurs, it may lead to wire flapping at the edges. Therefore, the condition of the dryer fabric edges should be carefully inspected every time the machine is stopped. Additionally, production personnel should note that although different dryer fabric may have similar lengths, their designs may vary, and in some cases, they may have been specifically matched. For example, dryer fabrics used in high evaporation sections often possess resistance to hydrolysis. Unless there is an emergency and spare parts are lacking, it is not recommended to arbitrarily switch the usage position of dryer fabrics.