What is a fire tube boiler?

In a fire tube boiler, high-temperature flue gas produced by the burner flows through a threaded pipe surrounded by water to heat a mixture of water, steam or soda outside the wall of the pipe to produce steam or hot water.

What is a water tube boiler?
The operation mode of water tube boiler and fire tube boiler is just the opposite, water in the boiler tube circulation flow, and the pipe is surrounded by high temperature flue gas, high temperature flue gas to the water pipe who heat, produce steam or hot water.

The main difference between the two types of boilers is:

1. Water tube boiler pressure range is wide, can break the pressure limit, can meet the steam supply requirements of more than 2.5MPa. Fire tube boilers are limited by material wall thickness and pressure and are used for pressure below 2.5MPa.

2. Fire tube boiler is shell boiler. Limited by the equipment and tooling of various boiler manufacturers, it is difficult to make fire tube boiler which is too large, usually below 35t/h.Water tube structure boiler can be realized into large scale boiler, and the boiler above 35t/h usually adopts the water-tube structure.

3. Fire tube boiler has a compact structure, under the same output, the shape and equipment weight are lower than fire tube boiler. Water tube boiler because of the larger volume, there is more space for the superheater arrangement, so the water tube boiler occupies a relatively large area.