With energy consumption being of prime importance in keeping operating costs optimized there are a number of design considerations at the PM Dryer Hood which can have a significant impact on energy savings.
The most important savings can be obtained by raising the hood's operating dew point temperature without the detrimental side effects associated with this approach.
In other words, securing an energy-efficient operation of the paper drying is possible all while maintaining good process control, good handling of the dryer section, good accessibility for maintenance service, a reduction of heat and moisture introduction into the machine room, minimum noise introduction into the machine room and long durability of the hood.
Recent developments permit the ability to reach operating dew point temperatures up to 62°C and 65°C. The supply air and the exhaust air quantity can be reduced by almost 20% when operating at 65°C compared to 62°C.
Both design concepts are applicable for new machines and retrofits.
The high dew point of 62°C is made possible by a thermally decoupled design, a highly efficient sealing system, specially constructed paper entry and exit slots,
On the other hand to reach 65°C further design considerations are required such as an exhaust air mezzanine which provides for additional protection against condensation, as well as a well sealed basement and effective pocket ventilation.