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Solutions to multiple poly roll cover failures, a case study

After blowing two expensive roll covers, a mill asked Valmet to investigate. After checking roll history, nip impressions and coolant, the culprit was an inexpensive part.

Proper bearing lubrication and modernization are essential

Most bearing failures can be traced to two maintenance oversights: a lack of lubrication or the use of the wrong type of lubrication. An upgrade may be needed.

Avoid winder vibration with modern software and hardware tools

Some paper grades generate winder vibration. Modern tools help, such as 4-way hydraulic valves, stiffer drums with lower dynamic runout and automated controls.

Optimize operations with a Roll Cover and Maintenance Agreement

Sending rolls to multiple suppliers can be expensive, cause a loss in continuity and create extra burdens for roll management. A roll agreement will help.

Precise head fit prevents uneven loading and excess cover wear

Machine component precision fittings are critical to papermaking success. Commonly misunderstood, head fits are an important part of every roll repair program.

Reel backlash due to worn parts causes sheet breaks, case study

Sheet breaks on PM1 are costing thousands of dollars. Valmet emergency service discovers backlash and further analysis provides temporary and long-term fixes.

SymRoll troubleshooting - leakage, cover wear and vibration

For troublefree function of SymRolls, the following are troubleshooting and maintenance tips and procedures regarding oil leakage, hydraulic and pneumatic systems, roll cover wear, roll vibration and other roll change factors.

Common hydraulic valves – cartridge counterbalance valves

Counterbalance valves prevent oil from leaving a cylinder that is holding a load. Without them, loads would move uncontrollably if oil pressure is lost.

Hot water modules for calender rolls, recommended maintenance

Calender rolls are heated via heating modules to provide low-variance accurate roll temperatures. Follow these hot water module maintenance best practices.

Stainless steel care, cleaning, surface prep and passivating

Stainless steel is corrosion resistant and maintains a film of chrome oxide over its surface. Under normal conditions this film is self-healing.