8 Key Data Points for Choosing the Right Dryer Fabric

A dryer fabric quote usually lists three numbers: width, length, and air permeability. 

But what works in one part of the dryer doesn’t work in the next, including temperature, airflow, dirt, and mechanical stress are all different from cylinder to cylinder. So choose a dryer fabric for each section separately, and keep a note on why that weave or mesh was picked.

Understand the Role of Each Dryer Cylinder Group

Before discussing the fabric structure, let’s first clarify what task the dryer fabric is expected to perform in this location.

The front section of the dryer cylinder group handles wetter, weaker sheets of paper, so it typically emphasizes support and operational stability. The strength of the paper sheet increases in the rear section of the dryer cylinder, but temperature, deposits, ventilation conditions, and the risk of wear may change.

At the same time, single-hang, double-hang, online, and offline operations place different demands on the main network.

Eight Key Data Points

Paper Grades and Basis Weight Ranges

Tissue paper, printing and writing paper, recycled corrugated medium, kraft paper, and pulpboard all have different requirements for dryer fabrics.

Different paper grades have varying requirements for dryer fabrics. For tissue paper and low-basis-weight printing paper, the focus is typically on the dryer fabric’s surface smoothness, air permeability, and their impact on wire marks, whereas for heavy-duty packaging paper, the emphasis is on the dryer fabric’s support capacity.

At the same time, the amount of adhesive substances in the waste pulp also affects the degree of contamination on the dryer fabric and the cleaning requirements.

Paper Machine Speed

As the machine speed increases, sheet control, dimensional stability, web guidance response, and aerodynamic effects become even more critical.

Both the normal operating speed and the planned maximum speed should be provided.

Selecting a model based solely on the current speed may become a limiting factor during subsequent production increases.

Drying Section Configuration

When evaluating the operating conditions of the dryer fabric, the following should be recorded: whether the paper machine uses a single-hang or double-hang configuration, the dryer fabric route, roll diameters, paper stabilizers, vacuum rolls, ventilation in the bag section, and the sealing elements near the dryer fabric.

Temperature and Humidity

The high-temperature, high-humidity environment inside the heat chamber is typically more severe than a dry-heat environment alone.

Therefore, when evaluating the operating conditions of the dryer fabric, it is important to assess the actual operating temperature, ventilation and pressure balance within the hood, condensation, and whether the dryer fabric filaments have become brittle or have undergone chemical degradation.

Air Permeability

Air permeability affects the flow of air and water vapor, but it is an operational parameter of the system and cannot be used on its own as a basis for determining the quality grade of a dryer fabric. 

During the assessment, the initial online values, trends observed during operation, and the status upon going offline should be compared.

Contaminants

Different types of deposits have varying effects on the structure of the dryer fabric and the cleaning methods used. Therefore, not all deposits can simply be treated as ordinary dirt. Resins, adhesives, paint components, paper dust, oil stains, and chemical deposits may require different cleaning methods.

In addition, you should note where the sediment first appeared and whether it follows a pattern in the transverse direction.

Dryer Fabric Tension Guiding and Edge Conditions

During normal operation, record the tension, the movement of the guide rollers, curling at the edges, points of contact, and whether the dryer fabric consistently drifts to one side.

Uneven tension or points of contact with the frame can both cause rapid damage to a properly fitted dryer fabric.

Therefore, if the problem stems from the condition of the equipment, it cannot be masked in the long term by changing the type of dryer fabric.

Dryer Fabric Interfaces and Installation Routes

Seams are a critical component of the dryer fabric. When selecting a dryer fabric, you should consider factors such as seam strength, thickness, joining method, installation space, and the risk of paper sheet marks, as well as the condition of the seams after the web leaves the machine.

Even if an interface is easy to install, it cannot be considered a reasonable choice if it is not suitable for actual operating conditions.