According to the location of furnace there are two types of fire tube boiler and these are external furnace and internal furnace type. There are mainly three types of external furnace fire tube boiler.
Types of fire tube boiler
1) Horizontal return tubular fire tube boiler.
2) Short fire box fire tube boiler.
3) Compact fire tube boiler.
There are also two types of internal furnace fire tube boiler
1) Horizontal tubular.
2) Vertical tubular fire tube boiler.
Advantages of Fire Tube Boiler
1) Compact in construction.
2) Fluctuation of steam demand can be met easily.
3) Cheaper than water tube boiler.
Disadvantages of Fire Tube Boiler
1) Due to large water the required steam pressure rising time quite high.
2) Output steam pressure cannot be very high since the water and steam are kept in same vessel.
3) The steam received from fire tube boiler is not very dry.
4) In a fire tube boiler, the steam drum is always under pressure, so there may be a chance of huge explosion which resulting to severe accident.