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Yankee rebuild improves tissue quality, a case study analysis

Rebuilding a Yankee is a daunting decision, due to OSHA regulations for confined space entry and the significant cost of downtime. This mill was losing product due to poor tissue quality, and Valmet's service engineers assisted in the decision making process to rebuild the Yankee.

Attenuators - operation, maintenance and troubleshooting

A pulsation attenuator, inserted in the stock approach piping, acts as a buffer for the headbox against pulsations developed by stock system components.

A solution for jumbo roll bouncing in the secondary arms

A mill reported that their jumbo rolls were bouncing. This started after their reel's flattened secondary arm rollers were replaced with fresh, round rollers...

Forming section field services identify potential problems

Forming section services diagnose potential or actual problems and their solutions. Scheduled services ensure reliable, safe and efficient operation.

Indah Kiat Perawang 50% time savings in doctoring, case study

When IKPP Perawang wanted to boost machine runnability and performance, they challenged Valmet's specialists to find potential areas for improvement.

Two front splicing methods and safety precautions with each

Two efficient winder front splicing methods are presented. Front splicing is more dangerous than rear splicing, i.e. nip hazards. One person should supervise.

Off-machine coater splicing is affected by several parameters

Splicing efficiency on coaters averages about 98%. Variables that affect the splicing process include primary roll speed match, paster roll speed match, paster roll gap, paster roll pressure, paper caliper/hardness profiles, splice tape pattern and tail length.

Instructions for safe removal of calender stack rolls and drives

Machine calender rolls are typically removed using a house crane and slings. This article presents typical stack roll removal instructions and safety. Always refer to original equipment supplier documentation and mill procedures for the actual procedures.

Excellent results with suction box showering, rebuild case study

A newsprint mill in southern USA was losing suction in one of their suction couch rolls. A Valmet rebuild resulted in two years of run time with very little internal pulp buildup or seal strip wear.

Vibration monitoring and analysis in tri-nip press, case study

A paper machine experienced vibration in its tri-nip press on the tending side only. Valmet condition monitoring and vibration analysis used synchronous time averaging (STA) to assist in solving the problem.