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PRODUCTS AND SOLUTIONS

iRoll for reeling and windingiRoll measures roll profiles automatically, online, directly at the winder or reel nip. The nip profile correlates directly with the diameter and hardness profile of the paper roll, clearly showing the peaks and valleys. When thousands of paper layers are reeled on top of each other, the thickness varia-tions are accumulated and make relatively large variations in the parent roll diameter and hardness profile.

Using iRoll with actuators such as calender zone controls, basis weight or coat weight profilers allows closed loop control of roll profiles. This enables an im-

mediate response to profile-related quality variations and runnability problems, and reduces recovery time after grade changes.

When used as a condition monitoring tool for reeling nip mechanics and controls, iRoll detects wear and enables correctly-timed corrective maintenance actions.

iRoll for measuring and controlling web tension profiles iRoll monitors the full-width tension profile continuously, online, and without any separate scanning devices. This helps detect uneven tension profiles at an early stage, long before they would be revealed at the

ImprovingpapermachineefficiencywithiRoll

Parent roll defects due to CD profile errors often result in lower line efficiency and higher costs per ton. Likewise, web breaks or complaints from printing houses, due to uneven tension profiles, increase costs and lose production. iRoll creates new options to improve web runnability and thus reduce production costs. It also provides mills with excellent end products. There are four iRoll applications available: reel drum, tension measuring roll, winding drum and the Portable iRoll service.

TEXT Tatu Pitknen and Susan Trast

iRoll operating principle. The same technology platform is used for temporary iRoll service measurements.

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1. Spiral mounted film sensors on the roll body for measuring nip load profiles

2. Roll cover3. Reel drum4. Signal processing module & transmitter5. Wireless power supply system6. Receiver that is conneted to the

mill automation system

RESULTS PULP & PAPER 1/2010 25

PRODUCTS AND SOLUTIONS

printing press. The iRoll tension measuring roll also allows closed loop control. There are multiple concepts for controlling tension pro-files and improving runnability. The actuators include press section steamboxes, drying section moisturizers or calender profiling.

Portable iRoll for process analyses and maintenance services The Portable iRoll service allows paper and board makers to analyze profiles online, and to do it quickly and cost efficiently without investments.

Portable iRoll for detecting reeling problems onlineThe portable iRoll service also measures reeling nip load profiles online. It immedi-ately shows reeling defects and variations in parent roll quality derived from the paper thickness profile, for example. iRoll detects force peaks, discontinuities and skewed nip profiles during parent roll build-up. With this information paper makers can

fine-tune reeling parameters and troubleshoot profile-related reeling problems that originate in earlier process stages

make bump tests to find responses with calender zone controls, dry weight, etc., and to optimize paper web properties

detect wear in reeling nip mechanics and controls

For nip load measuring purposes, the portable iRoll can be located on the reel, rereeler, calender wind-up, winder, or wherever precise information on the wind-up process is needed.

Portable iRoll for detecting tension profile problems onlineRunnability problems such as slack edges, wrinkles and web shifting are typically caused by uneven tension profiles. Port-able iRoll makes full-width, online tension profile measurements before the sizer, reel, calender, coating station or winder, and makes it possible to response test different actuators with bump tests and optimize paper web properties. Tension profiles can be affected by dryer section moisturizers, infra dryers, steam boxes or calenders.

Typical cases of use in practice The portable iRoll service has proven its potential and achieved excellent payback for paper makers many times over. Below are some typical cases:

1. Printing house complaints of bad run-nability due to slack edges and edge roll problems. Analysis consists of measuring tension and roll profiles to find tools to improve runnability, and process tests.

2. Off-machine coater problems due to web shifting and web breaks during unwinder splicing. Analysis consists of measuring tension and roll profiles to find causes of tension profile variations, and process tests.

3. Reel problems (crepe wrinkles and air bubbles) due to bad profiles. Analysis consists of measuring roll profiles to find causes of variations, and process tests.

4. Sizer, reeling and calendering runnabil-ity problems due to wrinkling. Analysis consists of tension profile measure-ments and process tests to reduce wrinkling and web breaks.

5. Offline-multinip calender quality and runnability problems (hard or soft roll edges, poor winder runnability). Analysis consists of roll profile measurements and process tests.

6. Winder problems (wrinkling, cracks, edge bursts). Analysis consists of winder profile measurements and analysis of previous processes.

7. Pre-studies for rebuilds. Portable iRoll, combined with vibration measurements, is a comprehensive tool for identifying bottlenecks when increasing machine speed. The analysis proactively solves difficult process and runnability issues which often arise after a rebuild and speed increase.

tatu.pitkanen@metso.com Tel. +358 40 869 7601

Installing iRoll Portable sensors on a roll surface.