Paper Machine Runnability Analysis
Sensodec 6S Paper Machine Runnability Analysis is an on-line tool to help machine operators achieve maximum runnability and sheet quality. It is also a powerful tool for diagnosing and correcting developing mechanical faults and process flow variations before they reduce paper machine efficiency. From the stock approach system to the reel, Runnability Analysis identifies the sources of high frequency process pulsations or mechanical vibrations that can lead to paper quality problems or even web breaks.
A paper sheet can break easily if the papermaking process is unstable or if there are excessive vibrations or pressure pulsations in the stock approach system, the forming section, press section, dryers or in any location where the sheet passes between roll nips. These instabilities can be caused by mechanical problems, process flow instabilities, roll roundness irregularities, roll imbalance or misalignment or by machine clothing.
To determine the causes of sheet instabilities, Runnability Analysis analyzes and compares vibration measurements, process pulsation measurements and product quality measurements at many locations in the papermaking process. It isolates the exact causes of instability to a specific machine component or to vibrations in a specific nip in a press section, size press or calender. It can pinpoint nip vibrations or quality problems caused by machine clothing. Runnability Analysis can also include dewatering analysis in the forming and press sections. In fact, the entire forming section or press section, including fabrics and guide rolls, can be optimized for high efficiency operation.
Paper quality variations and barring effects can be traced to stock delivery, the forming section, the press section, size presses or calendering operations.
Benefits of Runnability Analysis
- Pulsating components which causes flow instabilities in headbox can be seen and corrected.
- Cavitation in valves e.g. Headbox recirculation valve can be seen and corrective actions can be done to avoid possible quality instabilities.
- Runnability can be improved by changing felt tension, felt cocking or adjusting other press operating conditions.
- Roll covering materials can be selected for the their best performance.
- Roll cover damage can be forewarned and averted.
- Roll doctoring can be evaluated and improved.
- Roll grinding and preventive maintenance procedures can be improved.