Any air handling system is designed to deliver a certain amount of air under required conditions. In some cases the requirement of air is constant, while in others it can be very less, high or zero too. So, whenever air flow is required, a fan or blower provides the necessary air to the system. Depending on the application requirement, various types of fans are used in the industry.
In Boilers
Boilers are used in thermal industry where water is converted into steam by the aid of temperature.- The heat is produced by burning the coal. In order to burn the coal completely, it is important to supply enough amount of air to the boilers. Similarly after combustion, the exhaust gases are to be removed from the boiler.
- For the above process, the required amount of air can be supplied by draft fans.
- Boiler use two kinds of draft fans namely, forced draft fans and induced draft fans.
- Induced draft fans are fitted to remove the necessary exhaust gases from the boiler.
- The forced draft fans are provided at the inlet of the boiler from where air is supplied to the system.
- The usage of forced and induced draft fans increase the efficiency of boiler system.
- Industries can either use a forced draft or induced draft or combination of both based on their need.
- The usage of forced draft system generates a positive pressure whereas induced draft generates negative pressure.
In Industries where High Temperatures are generated
- Many engineering equipment are produced by either casting or by machining.
- In machining process the part is cut into tiny little pieces of metal called chips in order to get a required part.
- In casting process a complete new part is generated by melting the metal and then poured into mold cavity to obtain the required shape.
- Casting involves melting of metals which is achieved by producing high temperatures inside a furnace.
- The furnace is fed with required amount of air in order to complete the melting process.
- When melting is completed, the minute particles inside the furnace get evaporated into air which are to be discharged outside.
- So, to supply the required amount of air, forced draft system is used and to discharge the amount of gases fumes induced draft is provided.
- In the similar manner, other industries like in brick manufacturing, the required amount of air must be supplied to complete the process of hardening of the bricks.
- Similarly, in glass manufacturing industry, supply of air by fans is very important for blowing the glass.
Industries use draft fans in order to maximize the efficiency, and to minimize the cost of the system. Draft fans main application is to maintain the required amount of air and to completely remove the exhaust gases from the system.