Causes of deformation of standard line of press felt

Types of standard line deformation of press felt

Standard line lean left and right

Standard line protrusion

Standard line concave back

Standard line is S-shaped

Main Causes of Deformation of Standard Line of Papermaking felt and Preventive Measures

1. The tension on both sides of the papermaking felt is inconsistent, One side is small, the other side is big， When the papermaking felt is tensioned on the machine, the tension on both sides of the papermaking felt must be consistent. When the inconsistency is found, it should be adjusted in time.

2.The linear pressure on both sides of the press roll is inconsistent. During the pressurization process, the press rolls must be simultaneously pressurized on both sides, and the line pressure should be consistent. During the idle operation of the new papermaking felt, the line pressure should be adjusted as soon as possible to the line pressure during normal production, and long-term low-pressure operation should be avoided as much as possible.

3. The eccentricity of the two sides of the press roll,  couch roll and the squeeze roll are inconsistent. In the production process, it should be checked frequently whether the eccentricity of each press roll is moderately consistent, especially after replacing the papermaking felt.

4.The high setting of the press roll is unreasonable, the medium and high are too large or too small, and the line pressure is too large or too small. The medium-high setting of the new press rolls should be reasonable and accurate. During the use, the medium-high wear variation of the press rolls and the consistency of the nip pressure should be checked frequently to prevent the occurrence of abnormal wear and trouble. The intermediate height of the press roll is too large or medium and the pressure is not enough, resulting in the middle lordosis of the standard line of the papermaking felt. Since the line speed in the middle of the roll surface is larger than that on both sides, the papermaking felt in the middle contact with the roll surface has a faster line speed. Thereby, the standard line of the papermaking felt is convex in the middle. The standard line of the papermaking felt has a concave in the middle, which is mainly caused by the insufficient medium-high or medium-high pressure of the lower pressing roller. That is to say, the linear velocity in the middle of the roll surface is less than the speed of the two side lines, and the papermaking felt in contact with the roll surface has a slower line speed, so that the back of the standard line of the papermaking felt is concave.

5.The roller surface is not cleaned up in time. Keeping the surface of each roll clean at all times is good for reducing and eliminating the deviation of papermaking felt, discounts and standard line deformation.

6.The pressure roller has a displacement phenomenon, and the bearing damage is not replaced in time. In the normal production, we must pay close attention to the positioning status and lubrication status of each roller. It is found that the loose screws and the bearing heat damage should be taken in time to tighten, lubricate and replace, especially the felt roller of the Yankee cylinder.

7.Partial uneven wear of the rollers such as the support felt roller and the press roller. It was found that the roller with uneven wear first identified the cause and replaced it in time.