How to Select The Dryer Felt ?

The dryer parts of paper machines and the types of paper suitable for production are also different for different varieties of dryer felt. We should choose according to the different properties of the dryer felt. The relevant content on what types of paper machines and paper types different varieties of dryer felt are suitable for has already been introduced in the content of dryer felt types, and will not be repeated here.

When choosing and using dryer felt varieties, we should pay attention to the following issues:

The requirements for the performance of the dryer felt vary depending on the type of paper kind and the working conditions. There are two standards for selecting the dryer felt.

(1) Paper Quality Requirements

According to the requirements of paper surface quality, the selected dryer felt must not cause roughness on the paper surface and must meet the quality requirements of the paper, which is precisely the advantage of the dryer felt.

(2) Drying Efficiency Standard

It is necessary to effectively evaluate the drying efficiency of different dryer parts of the paper machine, and select a dryer felt (dryer fabric) with suitable air permeability based on the evaluated results.

Key Points for Selecting The Quality of Each Drying Zone of The Dryer Felt

(1) Wet Area

This area contains high moisture content and has the greatest impact on the surface of the paper. Special attention should be paid to the surface and joint status of the dryer felt. For paper machines that use waste paper as raw material to make paper, attention should be paid to the pollution of the dryer felt (dryer fabric); For high speed paper machines producing news paper, cultural paper, etc., attention should be paid to the problem of paper agitation in the dryer area.

(2) Main Dryer Area

This area has the highest water evaporation rate. To improve drying efficiency, high air permeability dryer felt (dryer fabric) should be used in this area. Generally, dryer felt (dryer fabric) with air permeability in the range of 1000-20000 cc · min-1 · cm-2 should be used. During use, special attention should be paid to the uniformity of moisture in the horizontal direction of the paper.

(3) Reel Section (After Paper Surface Sizing)

It is necessary to choose a dryer felt (dryer fabric) with appropriate air permeability, taking into account the curling edge of the paper and the uniform distribution of moisture in the horizontal direction, when using adhesive or coating liquid that is not easy to adhere and is prone to detachment.

Selection of Dryer Felt Size

1. Selection of Width

The width of the dryer felt should generally be 5-10cm narrower than the width of the dryer cylinder surface. If the cylinder surface has grooves for the paper guiding rope, the width occupied by the grooves should be appropriately added or removed according to actual production needs. When choosing the width of a dryer felt, it is also necessary to consider the different shrinkage amounts of different varieties of dryer felt. Generally, the shrinkage amount of ordinary dryer felt is larger, usually between 6-10cm, while the transverse shrinkage amount of BOM dryer felt and flocking dryer felt is smaller, generally not exceeding 5cm. Especially for dryer felt with a multi-layer structure, the transverse shrinkage amount is even smaller. Therefore, when choosing the width of dryer felt, it should be considered appropriately.

2. Selection of Length

The principle for setting the length of dryer felt is basically the same as that for press felt, which is the actual winding length when the tensioner is placed at 2/5 to 1/2 of the tightening direction. When choosing the length of the dryer felt, it is also necessary to consider the different elongation rates of different varieties of dryer felt. Generally speaking, the elongation rate of ordinary dryer felt is higher, ranging from 3% to 5%; The elongation of BOM dryer felt and flocking dryer felt is relatively small, generally in the range of 0.6% to 2%. The more layers of the base mesh of the dryer felt, the smaller its elongation.