A good closed hood - the key to an overall optimization of the dryer section ventilation

The features of the closed hood covering a multi-cylinder dryer section of a paper machine will have an extensive impact, not only on several production efficiency parameters but also on the overall working conditions in the paper machine hall.

A closed hood in poor condition will not only create problems for the production but can also have negative impact on the building constructions, due to humidity loads being spread uncontrolled.


A closed hood designed for a high humidity dew point will allow the dimensioning of the dryer section exhaust and supply air systems at reduced air flows, meaning less investment costs into these equipment, more suitable applications especially when talking about space limited rebuild projects and more efficient overall heat recovery solutions.

The EVG closed hood design is user friendly, with attention paid to the overall accessibility and possible service needs in the paper machine. Special lifting door arrangements, easily dismantled roof panels and wall service doors are included, taking into account any specific customer need.

Operation at high humidity is ensured by a design where any risk for cold bridges causing condensation has been eliminated. The design including proper sealing materials will also cut off any possible air flows from the upper part of the closed hood into the machine hall. A tight overall construction also give the paper maker an excellent tool to control the so called 0-level of the dryer section and thus minimize any disturbing air flows either coming from the hood or going into the hood, including the basement area under the machine.
 

Main benefits with a high dew point closed hood:

  • Improved overall energy efficiency of the dryer section ventilation
  • Reduced amount of exhaust and supply air flows with a positive impact on the overall investment costs
  • Improved working conditions in the machine hall, due to minimized heat load and good noice attenuation
  • Reduced environmental impact through efficient heat recovery solutions and equipment sizes