- Artificial Draught Definition: Artificial draught is a method using steam jets or forced air to create pressure differences, reducing the need for tall chimneys.
- Induced Draught: Utilizes a fan to suck flue gases from the furnace, creating a pressure difference that draws fresh air into the system.
- Forced Draught: Uses a blower fan to push air through the furnace, creating positive pressure and efficiently driving flue gases towards the chimney.
- Balanced Draught: Combines forced and induced draught methods, using fans at both the furnace entry and exit to optimize airflow and combustion.
- Efficiency and Cost-Effectiveness: Artificial draught systems enhance efficiency and reduce costs by optimizing heat extraction and minimizing the need for tall chimneys.
The expression of the pressure difference between inside and outside of a chimney shows that it has a term which is the height of the chimney. To achieve sufficient pressure difference between two points or to attain enough natural draught we have to increase the height of the chimney which is not always practical in the view of cost-effectiveness. In those cases, we have to think about artificial draught instead of natural draught. We can achieve artificial draught, mainly with two methods. One gets produced by steam jet, and forced air produces another. Introducing artificial draught one can significantly reduce the height of the chimney to fulfil the same purpose removing flue gasses to the atmosphere.
Induced Draught
An induced draught system uses a fan at the base of the chimney to suck flue gases from the boiler. This creates a pressure difference that draws fresh air into the furnace. Unlike natural draught, induced draught does not rely on the flue gas temperature, allowing more efficient use of heat. After extracting most of the heat, the cooler flue gases are forcefully removed through the chimney. This system can achieve the same results as a tall chimney, but with a shorter, more cost-effective design.
Forced Draught
Forced draught is similar to induced draught, but it uses a blower fan instead of a suction fan. The blower fan is placed before the coal bed, blowing air into the furnace. This preheated air pushes flue gases through the system towards the chimney. Forced draught creates positive pressure, so it’s important to prevent leaks to maintain system performance.
Balanced Draught
Balanced draught combines forced and induced draught systems. Blower fans are placed at the furnace entry, and induced fans are at the exit. This system uses forced draught to push air through the furnace and induced draught to pull gases out, ensuring efficient combustion and gas removal.
