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Blade doctors - purpose, design, operation, examples and options

Doctors are used to scrape foreign material off rolls or to redirect the web to prevent wrapping around rolls. Doctor components vary, but all blade type doctors will have blade(s), blade holder(s) and beam. Heaters, oscillators, air blows and catch pans are common additional options.

Positive and negative considerations when grooving suction rolls

Grooving suction rolls is a commonly undertaken process. This article answers some of the most frequently asked questions, such as: why groove the suction press roll, how does grooving affect the cover's P&J, and are there any concerns or drawbacks with grooving a suction roll.

Example equipment update analysis - rebuild/replace/add a winder?

When examining an older piece of equipment that does not meet today’s performance requirements, a mill must determine if it should be rebuilt or replaced.

Calendering variables, properties, compression and plasticity

Behavior of paper properties during calendering and a description of the mechanisms of smoothness, gloss and web plasticity and response to compressive load.

Balancing rolls - balance and imbalance, isolating the problem

Unbalanced rolls hammer at the framework of the papermachine, leading to worn journals, bearings and covers. Balancing rolls lengthens component lifetimes.

Three things about refining

Read three highlights of Valmet´s refining technology and learn how we can help you to improve performance and increase efficiency across all refining applications.

Avoiding roll defects at the winder - causes and solutions

Most roll structural defects are caused by poor nip or tension. These tips will help operators avoid starring, soft starts, corrugations and crepe wrinkles.

Avoid the wrinkles and web breaks that result from poor splicing

Splicing offers little reward for a job well done, but big penalties to the bottom line for poor quality workmanship such as when customers return shipments.

Improved drying - Reduce thermal resistance with spoiler bars

Spoiler bars increase drying capacity up to 30%, with improved drying uniformity and CD moisture profile control. A kraft bag case study demonstrates.

Optimize doctoring performance and lower total cost of ownership

Every doctoring process can be improved. The usual investments required are minimal. Optimizing your doctoring processes results in better runnability, improved quality, optimal production efficiency, reduced maintenance costs and improved safety and environmental effect.