Mastering Solutions for Press Felt Woes in Paper Manufacturing

Paper machine clothing is a key component in paper production, including press felt, forming fabric and dryer fabric. The quality of press felt will have a significant impact on the operation, downtime and cost of paper machines. In actual production, the good condition of the press felt should be ensured as much as possible. In addition to correct selection, regular cleaning and inspection, possible failures should be reduced.

Press felt deviation

Press Felt deviation may be caused by the following reasons:

（1) Failure of the automatic correction regulator;

（2) The palm touches the guide roller or frame by mistake, causing malfunction;

（3) One side of the press felt is loose and the other side is tight, resulting in serious deviation of the standard line;

（4) A guide roller in the press felt loop is deflected;

（5) There is pulp wrapped around a guide roller or the edge of the press felt is wrapped too much, resulting in inconsistent line speed;

（6) The two pressing rollers in the pressing area are not equal and the contact at both ends is inconsistent, etc.

In production, ensure that the guide roller and the pressing roller are parallel, adjust the press felt tensioning roller, and check the felt corrector regularly, etc.

Press felt pleating

In addition to the pleating in the middle due to the inconsistent tightness of the press felt and the pleating on the edge of the press felt or the whole press felt due to excessive deviation, there are several possible situations:

（1) Pleating on the edge of the press felt. If the edge width of the press felt is slightly deviated, it is easy to hit the bearing of the press felt roller and pleat. Just tear off a part of the press felt and adjust the corrector to make the press felt in the middle.

（2) Pleating in the middle of the press felt may be caused by too much skewness of the standard line due to operation or other reasons; too much pulp or debris on the guide roller, wet paper can easily cause the blanket to pleat in the middle.

（3) Pleating in the middle of the press felt may be caused by the reverse installation of the press felt spreading roller; a roller that does not rotate due to a malfunction can also easily cause the press felt to pleat in the middle.

If the press felt is found to be pleated, the machine should be stopped immediately for inspection, and the pressing roller should be lifted at the same time. After loosening the press felt, the press felt should be flattened to find the cause and deal with it.

For high-line-pressure paper machine press felt, once pleated, it is difficult to repair and they are usually crushed, so special attention should be paid to inspection and maintenance during use.

press felt pressure damage

In addition to edge shedding, pleating, and deviation, blanket pressure damage may also be caused by the following reasons:

（1）The felt loop is too sticky, loop maintenance, or parts falling from the frame enter the pressure area;

（2）Pulp or wool balls on the frame fall into the press felt loop, and hard debris brought by the mesh;

（3）Uneven pressure on the press roll or press felt damage caused by welding and other reasons.

If there is a big hole in the press felt, it should be considered for replacement. If there is a small hole in the press felt and the quality is good, sewing measures can be taken to temporarily repair it to maintain production.