Dryer Inspections and Paper Dryer Performance
The dryer section of a paper machine consumes large amounts of energy and can have a dramatic impact on the quality of your sheet and your bottom line.
The following are best practices for paper dryer inspections used for preventative maintenance purposes:
- Dryers should have routine external inspections, looking for loose equipment, steam leaks, oil leaks, and proper lubrication flow rates. Leaking steam valves, rotary joints, and flexible hoses should be replaced or repaired. Oil leaks should be repaired and oil spills cleaned, for operator and machinery protection.
- Dryers should have routine internal and external inspections. The ideal inspection frequency is every year. As a minimum, all dryers should be inspected on a five-year rotating cycle (20% of the total number of dryers per year).
- The frequency of internal dryer inspections may be a requirement of the insurance carrier.
- Observations and measurements should be documented for future reference and for follow-up.
- General external inspections should include ultrasonic shell thickness scans, magnetic particle inspections of the dryer heads, head bolt inspection, and review of pressure safety equipment.
- Internal inspections should include integrity of balance weights, condition of syphons and supports, condition of the dryer inside surface, condition of dryer bars, (bars, hoops, springs, fasteners), and locations of bars (if partial-width bars are used in the dryers).
- External inspections should include head flange leakage, manhole cover leakage, head condition (surface cracks), doctor blade wear pattern, and shell surface condition.