Machine Hall Ventilation

The Main benefits:

• No harmful condensation on the building
• No corrosive damages on steel constructions or building cold bridges
• A good working environment with acceptable humidity and temperature level

Normally such new supply air units including needed heating coils are connected to the existing heat recovery circulation water system. Additionally, needed machine hall exhaust air units are to be located as close to the heat and moisture source as possible.

The paper making process with all its moisture and heat loads is putting high demands not only on the process ventilation equipment but also on the general machine hall ventilation solutions. The exhaust air system connected to the closed hood covering the dryer section will take care of the major part of the heat and humidity load coming from the process.

In addition to this local process exhausts being installed in different parts of the production line, like forming section and process pulper exhausts and mist removal systems in connection to HP water showers will further decrease the heat and humidity loads.

To balance the amount of air being exhausted from the process and normally blown outside, the building must be equipped with an appropriate machine hall ventilation system, dimensioned for a good overall balance both during cold winter and warm summer periods.

In rebuild projects of existing paper machines attention is also to be paid to possible changes in the air balance of the machine hall building. Additions in the process exhausts should always be countered by additions also in the machine hall ventilation equipment. This to guarantee an adequate balance also after the rebuild.