The Press Felts play an important role in the paper web after the forming section, giving it smoothness while transporting it to the drying section. Depending on their position on the paper machine, they can be classified as wet felts, top felts and dryer felts.
In addition to removing the most moisture from all press felts, the pick-up felts must pick up delicate sheets from the forming fabric and guide them into the press section. Problems in the pick-up area often result in breakage of the press section.
How can you prevent breaks in the press section of your paper machine? As a Press Felts manufacture, I will share with you.
Press Felts
Water will smooth the paper side of the blanket and improve the tackiness of the blanket. The additional water will increase the water pressure in the first press section. This can lead to better dewatering, but if taken to the extreme, it can also lead to pressing - about which I will write next time.
First, the tension of both fabrics must be equal across the width of the machine. Therefore, measure the tension on both the soft side and the drive side. Make sure that the guide lines are as straight as possible.
Next, if possible, increase the tension of the forming fabric a little. After that, you can also play with the tension of the jacquard felt. A little slack or a little tighter may be fine.
Push the pick-up roll a little deeper into the forming fabric.
This increases the load on the still fragile sheets, so be careful with this option. Look at the pickup point from the back of the fabric (machine) with a bright light to see if the pickup roll is being pushed evenly into the fabric over the entire width of the machine. If not, you may have some alignment work to do.
Press Felts
Some mills run their press felts slightly faster, and some have the same speed setting for both fabrics. In fact, speed differences are very subtle in the jacquard area. A common cause of speed differences is incorrect slip or roll diameter settings. The actual speed of the drive rolls, forming web and pickup felts can be easily measured.
When hard initial dewatering occurs on the forming table of the machine, the fibers are dragged into the dewatering holes of the forming fabric. The forming web slowly loses its dewatering capacity, sometimes compensated by increasing the vacuum in the forming section. All of this results in the fibers being stuck vertically in the forming web, making it more difficult to release at the pick-up point. Moving the ejector contact point further onto the forming table, reducing the angle of the first dewatering foil, and ultimately reducing the vacuum on the first vacuum foil box, will improve sheet release at the pickup point.
These troubleshooting tips above are just five of many solutions to Paper Machine Felt problems. In addition, the design of the blanket must be appropriate for your machine and situation. For more information and assistance, please contact us.
