Boiler Draught and classification of Draught

Boiler Draught:

Boiler draught is the supply of air into the combustion chamber which creates the pressure difference in between atmospheric pressure and boiler pressure. with the help of fans, Draught is balanced in the boiler.The flow of air takes place due to the difference in the pressure and this flow is known as draught. Boiler draught is used to maintain the required air flow into the combustion chamber for the better burning process and it carries the hot gases away.

Classification of Draught:

Draught Cane be Classified into Following Types:

• Natural Draughts
• Artificial Draughts

Natural Draughts:

This type of draught is created by using a chimney. Natural draught can transfer waste gases into the atmosphere and used to regulate the airflow into the combustion chamber.

Artificial Draught:

An artificial draft is developed to maintain the required supply according to the load adjustment and this type of draught is used with irrespective to the atmospheric conditions.

Artificial Draughts are two types:

Mechanical Draught:

Mechanical Draught system is divided into two Types They are

• Forced Draught
• Induced Draught

Forced Draught: 

This is a type of pressure Draught, which supplies the requires air flow into the combustion chamber with the help of external fans.

Induced Draught:

It is used to supply the required air flow with the help of fans but in this type of draught, the air is supplied by placing the fans below the chimney.

Steam Jet Draught:

In steam jet Draught, with the help of forced draught or induced draught, the flow of air is created and supplied to the combustion chamber. This type of method is useful to burn the fuel efficiently.