Runnability issues can be solved
Good runnability means continuous machine operation with minimal web breaks, while machine productivity and the amount of waste stay at the desired level.
As a papermaker, you are often faced with various runnability issues. These include a high number of web breaks or problems with tail threading or end product quality.
Or perhaps you need to increase the machine speed but do not know how to eliminate possible runnability issues in the dryer section? Or you have already increased the speed and now have too many web breaks on the machine?
Don’t worry. Whatever your problem, we at Runtech are able to help you. By following the five steps described in this eBook, you will be able to easily improve your machine runnability.
Find the bottlenecks and potential through a runnability audit
The very first step to improve machine runnability is to extensively analyze the process factors from the wet end to the reel. A comprehensive runnability and efficiency audit performed by Runtech professionals will help you identify your machine bottlenecks as well as discover much needed improvement potential.
Each audit comes with a full written report, including a summary of the results as well as a detailed analysis with recommendations tailored to your process and equipment. We also provide you with insights on how to get the most out of your equipment.
Ensure efficient press section doctoring
Did you know that runnability improvement actually starts in the press section? This is because dewatering and doctoring play a major role in paper machine runnability.
The most efficient and economical method of water removal in the press section is nip dewatering. Well-designed and well-built save-alls with integrated doctoring are essential to gain the full benefit from increased nip dewatering and ensure efficient water discharge with perfect rewet prevention.
The effects of efficient dewatering are significant. The increased dry solids content after the press improves web wet strength, making the web stronger and allowing it to withstand unstable conditions in the drying section. This, in turn, is directly related to dryer section runnability, since good tensile strength reduces web breaks and improves end product quality.
Shorten your open draws
There is typically an unsupported sheet draw between the press nips or between the press and the dryer section. Moving surfaces, such as felts, fabrics, rolls and the web, create considerable air flows and pressure differences that cause sheet flutter.
The problem can be solved by modifying the roll geometry to shorten the open draw as much as possible and optimize the sheet transfer. This boosts runnability, enables machine speed increase and improves end product quality.
Stabilize the dryer section through better web support
Especially in high-speed paper machines, the first single-felted dryer groups can be very problematic to run, as the web is still very wet and breaks easily. Without high-vacuum support, the wet web tends to follow the upper cylinder, resulting in breaks and paper defects. Runtech’s EV EasyOne web stabilizer prevents the web from doing this by further reducing the draw, improving paper quality and increasing machine speed.
In the double-felted area, runnability problems are more common than in the single-felted sections. Long unsupported sheet transfers increase runnability problems, causing a high number of breaks.
Reducing unsupported draw by 25–50% between the top and bottom dryers enables trouble-free runnability and supports ropeless tail threading. Runtech’s EVdf web stabilizers ensure better drying capacity due to the reduced pocket humidity levels and wider sheet wrap against the drying cylinders.
Change to ropeless tail threading
Ropeless tail threading not only improves operator safety significantly but also shortens tail threading time during web breaks by up to 80%, thereby increasing production. In many cases, the technology makes it possible to increase machine speed without compromising operator safety.
Runtech’s Press RunShooter delivers the tail directly from the center roll to a separate press or from the press to the dryer section. Optionally, the tail can be delivered directly to the dryer section ropes. The system can be semi or fully automatic.
Let’s achieve better results together
The actions described earlier will enable you to improve your machine runnability and reach the best results – step by step.
At Runtech, we understand causes and effects in the papermaking process. In addition, our services and technology help you save time and money.
Interested and ready to improve your machine runnability? For further information, please contact us to discuss how we achieve better results together.
Source: Runtech Systems