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Reading fluids circuit diagrams - hydraulic & pneumatic symbols

Reading hydraulic and pneumatic circuit diagrams and being able to make sense out of them is a valuable skill for mill personnel. The first article in this series presents fluid control elements.

Review of the types of roll misalignment and alignment methods

Alignment of rollers is critical to keep the web and fabrics running true without wrinkles and tight/baggy lanes. Where the rollers are determines how good the alignment must be.

Journal inspection, dryer bearing fit and internal clearance

After a dryer front bearing has been removed, the bearing fit and new bearing to be installed internal clearance should be inspected. The following procedures cover journal and bearing inspection.

Field Report - Minimizing paper curl

Paper curl is critical for many grades of paper, such as copy machine paper, papers that get coated and printed on and multi-layer paperboard grades.What causes curl and how can it be minimized?

Troubleshooting roll bouncing addresses the four probable causes

Roll vibration can intensify enough to actually bounce the rolls, causing an unsafe situation at the winder. The most common causes are mechanical hardware, controls, roll structure and paper properties. Thorough troubleshooting is the best recommendation.

Common fluids valves explained: Cartridge pressure relief valve

Pressure relief valves are used to prevent over pressurization in the hydraulic circuit. They are located close to the pumps and reservoir tank or close to the equipment to safeguard from over pressurization.

Winders require a consistent preventive maintenance program (PMP)

Sheet breaks at the winder can bring the entire papermaking process to a stop. To prevent this, the winder needs constant attention through a sound preventive maintenance program (PMP).

Size press roll wear causes reel wrinkles and culls, a case study

A P&W paper machine suffered from excess wear on the back edge of the bottom size press roll. The problem was traced to the size press synchronization shaft. When the shaft was replaced, the roll wear problem went away.

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.

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.