Causes and solutions for vibration of seamed press felt in paper production

What is a seamed press felt?

Seamed press felts are commonly used in pulp board machines and are a special type of press felt. Sun Hong uses special seaming technology to connect the two ends of the press felt to form a closed ring structure, which can be quickly installed and replaced. It can be inserted into the pressing section without disassembling the paper machine rolls and other parts, shortening downtime and reducing labor costs.

Difference from needle punched press felt

Traditional needle punched press felts are seamless in structure. Installation requires stopping the machine to disassemble paper machine parts. The installation process is complicated and the downtime is long. The two ends of the seamed press felt can be spliced ​​to form a continuous ring press felt. It can be installed directly on the paper machine without moving the parts on the paper machine. Compared with traditional press felt, it can greatly save installation time and quickly reach normal operation.

What are the causes and solutions for the seamed press felt that sometimes vibrates during operation?

Seam press felts of the same specifications often produce strong impact when passing through UB. The reasons for the impact are as follows:
(1) Insufficient lubrication. No lubricating water is used or the lubricating water cannot be kept. As a result, the water lubricating layer cannot be formed between the panel and the press felt, and the friction heat and resistance increase.
(2) The structure and operation status of the seam: The seams is not strong enough or are uneven, and the uneven force when passing through the water suction box causes periodic vibration.
(3) Abnormal tension of the seamed press felt: The tension of the seamed press felt is too small or the lateral contraction is uneven, which leads to aggravated vibration during operation, especially when passing through the water suction box, it will cause vibration due to the change of local resistance.
(4) Incorrect vacuum setting, too high vacuum: Too high vacuum will increase the adsorption force of the seamed press felt and the water suction box, aggravate friction and vibration, and may also cause local deformation of the press felt, affecting the operation stability.
Solution:
For the adjustment of the flatness at the seams，Producing seamed press felt, in order to enhance the strength of the seams, special hot-melt fibers are added to prevent lint shedding at the seams.