Control hood ventilation for energy savings in drying

EV Hood Manager™ controls automatically hood ventilation for improved runnability, energy saving and working conditions.


The automatic control of the hood balance is based on the pressure differences in the hood. The upper part of the hood is always over pressurized while the basement is under pressurized. Pressure differences force hot, humid air to flow from the upper part of the hood. Respectively, cool machine hall air flows from below the 0-level into the hood.
 

The 0-level is the height, where air pressures are equal in- and outside of the hood. This level has a great effect on production factors, energy consumption and the quality of paper. Changes on 0-level indicate problems of hood ventilation system.

EV Hood Manager includes automatic control system optimizing the exhaust and supply air flows. Automatic control is based on the following energy-economical principles of the hood:

1. High humidity of exhaust air decreases specific energy consumption in drying section.

2. High humidity of exhaust air increases heat recovery efficiency.

Optimization of the hood ventilation brings several benefits:

  • Energy savings in drying
  • Less runnability problems and breaks in drying section
  • Improvements in moisture profile and paper quality
  • Better working conditions in the machine room
  • Elimination of condensation on constructions and frames