Where safety, efficiency and innovation merge to redefine excellence
The upgraded reel offers an unparalleled operational experience, allowing mill personnel a comprehensive view of the process. Designed to reduce downtime, the reel allows adjustments during continuous operation, always under safe conditions with the highest standard of operator safety. Several subsystems have been improved to increase the productivity and reduce roll handling time.
The tail threading and turn-up glue system are more precise, and the weighing of parent rolls are more accurate. There is an increase ability to handle spread of spool diameters from 400-550 mm and the spool storage can handle six spools. Another important change is that the cabinets have been reduced by 30% and there is a new infrastructure for cabling and hydraulics to speed up installation and troubleshooting, improve housekeeping and safety.
The operators have also more possibilities for adjustments during operation. The frame and walkways are redesigned to simplify housekeeping, increase visibility of roll building and to improve access to the machine.
Valmet has been leading reel safety forward during many years and takes additional steps regarding reel safety with the new generation of SoftReels, which are compliant with SS-EN 1034-1:2021 and SS-EN 1034-17:2012.
- Safe operating practice at Yankee doctor area, with two-hand operation during Yankee doctor movements.
- Safe dressing procedure in dressing area during winding. The lifting of the parent roll during weighing has been removed.
- Smart Safe Operator Areas (SOA zones), with electrical guard locked doors with request to enter. The SOA zones are defined to minimize interference with production. Each SOA zone is separate and it is not possible to walk between zones inside the machine since each SOA zone only can be entered from tending or drive side of machine. The SOA zones make it easy to work in a safe manner both for new and experienced operators.
- Add-on features, that enable automated assistance for manual handling, are the parent roll pusher pushes the parent roll along the kitchen rail to the first station, if needed and the broke pusher pushes broke from the dressing station to the pulper opening.
Next generation winding: InWoundCaliper control
The winding quality is crucial, it defines the start of the final tissue product. The reel can sometimes be complex to understand: what load should be applied or when to use the Control Wind Assist (CWA)? A very common issue in the industry, as a consequence of incorrect settings, is caliper variation in parent rolls with low caliper in the beginning and high in the end.
Valmet is taking on a new approach to further improve the quality and usability through the new control mode InWoundCaliper (IWC). The IWC gives:
- An increased caliper preservation, for example, fiber and bulk saving.
- Increased yield in converting. Less need of embossing to compensate for large caliper variation. Less adjustments in converting due to diameter differences of parent rolls.
- No need to find linear load curves and CWA settings for different grades. Easier to understand how to set up the winding.
- Less dependent of friction over time.
Functional description
In-wound caliper is defined as the thickness of the sheet in the wound stage. The IWC is targeting maximum in-wound caliper during initial winding and after a set diameter targets to keep the in-wound caliper constant. This has been proven to be an effective way to increase the caliper in the beginning of the parent roll and to enable a more constant in-wound caliper with growing diameter.
The ability of the software to restrict and control the linear load depending on the caliper response during diameter growth makes roll building adaptive to incoming and changing sheet properties. The software is targeting the shape of the roll and will continue to repeat the shape and not restrict caliper growth through creping blade life or grade change.
Verification and tests
The new functionality has been verified at Valmet customer sites. Bath grades are more sensitive to pressure, and this has been the subject during the trials. To be able to compare the performance of the software, two sets of rolls were produced during the same conditions.
First a set of three rolls running a typical load control curve and then a set of three rolls using the IWC software. Boths sets were produced after blade change.
How does the winding settings affect the caliper?
Tissue is sensitive to pressure since the sheet is compressed during winding. Valmet has studied caliper losses as a function of time, pressure and humidity at Valmet Tissue Technology center. The study found that:
- There is a correlation between pressure and caliper losses; higher pressure gave more caliper losses.
- A humid environment, in combination with pressure, accelerate the caliper losses.
- The caliper shape in the parent roll changed over time.
- The caliper recovers during unwinding, in-wound caliper compared with measured caliper. Saying that tissue is both compressed elastic and plastic during winding, but the elastic ratio of deformation decreases by time.
- Tissue that has been unwound and then stored in a humid environment recovered some more caliper. Saying that humidity gives a recovery boost to tissue in nonpressurized condition.
How does the caliper variation affect the converting?
A parent roll with a caliper variation will affect the converting efficiency due to the need of additional machine adjustments. The diameter reduction will not be steady during unwinding and continuous adjustments are needed to keep up the tension.
Parent rolls with caliper variation will affect the thickness of the end product. This sometimes requires additional logistics to mix rolls with different diameter to compensate for the variation.
End products with little embossing will not be able to compensate for the caliper variation and the diameter and firmness quality will be affected and vary with parent roll diameter. Caliper variation is often noted in products with many meters, such as awayfrom- home products.
The SoftReel offer
The new IWC software is an add-on option for the new SoftReel L. The software is accessed through the machine control interface and is an alternative way to control the reel; the classical load control is still in the delivery.
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