How to prolong life span of papermaking machine felt
April 3, 2023
Why is my felt changing so frequently and so quickly?
Do you have such the question?
This is because paper machine felt is a consumable product.
Careful use and maintenance are important for producing good quality paper and reducing costs.
In order to pursue greater economic benefits and better product quality, it is essential to understand the causes of felt wear.
Here we together learn some know-how to prolong lifepan of the felt in the process of use.
What is a papermaking machine felt
Paper machine felt is a material used in the paper industry. It is mainly used for paper forming, wet paper dewatering and paper transportation. It has good dehydration, smoothness, wear resistance and stability.
The classification of papermaking machine felt
Paper felts can be divided into wet felts, upper felts and dry felts according to the part on the paper machine.
The wet felt runs on the paper machine with water, and its function is to press the paper blank to make it dehydrated and
the paper surface smooth. Wet felts have good water filtration and elasticity, high strength, low shrinkage, wear resistance, and resistance to bacteria and acid and alkali corrosion.
The upper felt is used on the upper of the wet felt, and a small part of it touches the dryer to lead the paper, flatten the upper and dry the paper, and has the properties of flatness, stiffness, good elasticity, wear resistance and high temperature resistance.
The cylinder felt, also called dry felt, is used in the dryer part, with the thickest texture, weighing more than 2000g per square meter, and has good strength.
Characteristics of paper machine felt
- 1. Strong compaction resistance.
- 2. Long-term wear resistance and plasticity of felt.
- 3. Extremely high elasticity and recovery.
- 4. Smooth felt and even pressure distribution.
- 5. High drainage capacity and large void ratio.
The Problems and Solution of the Paper Making Machine Felt
1.Felt edge wear
The main reason is basically the paper page outside the felt breathability high resulting in small wear of felt moisture.
1) insert the seal of the suction box to the edge of the paper sheet;
2) add a spray hose on the inside of the felt;
3) control the vacuum of the suction box.
2.The edge of the felt falls off
it is the phenomenon that the two sides of the paper sheet are not stable under the absorbing and shifting felt.
Adjustment method: appropriately increase the width of the suction and removal roller width and strengthen the felt washing. At the same time, poor water needle cutting will also have an impact on the edge of the felt falling or with the edge.
Note: The paper side of the suction and removal rollers at the relatively serious plugging holes
The press is not pressurized and the vacuum or vacuum suction box valve is not opened during crawling.
1) When the press section is crawling and running, first close the press area and turn on the vacuum.
2) The wetting condition of the felt should be consistent throughout the whole width, and the shrinkage of the felt should
be consistent throughout the moisture, and the operation should be relatively smooth. So in the case of long downtime,
we should wet the felt fully every time to ensure that the moisture content of the whole felt is consistent. If the moisture content of the entire felt is not consistent in the case of long downtime and the urgent need to start the machine, you can
add a water pipe to wet the felt in front of the water suction tank.
3) It is to keep certain tension and the sensitivity of the calibrator runaway alarm to ensure that the felt does not runaway.
4) When adjusting the position of the felt, it is better to use the method of moving the corrector and try to avoid adjusting
the air tire pressure.
4.The whole paper sheet goes with the felt
There are several reasons why the paper sheet is not transferred to the stone roller with the vacuum pressure roller after
1) the vacuum pressure roller vacuum is low;
2) the moisture content of the felt is large and the felt has reached the late stage of use, the moisture content is large and dewatering is difficult;
3) the vacuum pressure roller vacuum area is on the upper side, resulting in the high vacuum area out of the pressure roller and stone roller contact area.
If you do not have the condition to replace the felt, you can try to adjust the vacuum degree and high pressure water of the upper felt, or reduce the vacuum and high pressure washing of the lower felt.
Of course, the effect may not be too good if the felt runs to the later stage, and you can try to adjust the felt tightening degree, which will also have some effect.
Paper machine felts are an integral part of the paper making process. Although paper machine felts account for only a
small part of the total cost, their quality has a significant impact on paper production.
The price of each felt is around 60,000~100,000 RMB. Proper and reasonable use of felt can better prolong its life span, reduce overhead and save costs.