May 10, 2016
The process of changing from a full reel of paper to the empty spool must be done flawlessly every time if downtime is to be low and paper yield high.
Turnup equipment varies by machine. You have your workhorse Pope reel with primary and secondary arms. Pope reels can be equipped with primary arm nip relieving cylinders, air goosenecks, tape turnup systems, or water jet turnup systems. They can be hydraulic or pneumatic operated.
Then there are reels which have drives on both the primary and secondary arms. These types of reels have goosenecks, air showers, or full width cutting knives to break the sheet at turnup.
Occasionally, the sheet will not widen out all the way to the edges. This can be caused by improper alignment of the primary arms to the reel drum, spool nip load profile issues, or a web that wants to tear easily in the machine direction (MD/CD tensile ratios too high). This phenomenon can be caused by too high of rush-drag, high fiber orientation, or headbox edge flow/header balance issues.
In the Before Rebuild graphic, we see that the poor control of nip load (blue) during the reel turnup process has a negative effect on the roll density (green). When technological upgrades such as the options mentioned below are done to the reel, the After Rebuild graphic demonstrates the constant nip load and the smooth roll density. How is this achieved?
If you need more information regarding turnups or bottom waste reduction, please contact our Reel Product Manager, Todd Vanden Heuvel at todd.vandenheuvel@valmet.com.