This kind of boiler adopts single longitudinal drum, *-pass gas traveling and water-fired tube structure. There are two sets of spiral fire tubes in the drum, the boiler water natural circulation, depend on water cool tube and drum bottom heat surface radiation heat exchange and fire tubes convection heat exchange to produce steam continuously. The boiler employ hand fire grate and rational secondary air guarantee complete combustion. The high temperature flue gas of the fuel combustion products, firstly through the afterburner up the bear arch enter into the first fire tube bank, then into the front gas box and turn back the second fire tube bank., and enter the economizer heat the feed water, finally,

drew out by the IDF to the dust collector and discharge from the chimney.

The boiler advantages can be summed up as follow:

1.   Adopt spiral fire tube to increase the heat exchange efficiency.

2.   Special secondary air arrangement guarantee complete combustion.

3.   The drum adopt arch tube plate, which is good durability, long service life and low breakedown rate.

4.   Bigger grate surface and full boiler steam rate.

5.   Full sealed air duct and high combustion efficiency.

6.   Change *0g with *6MnG to reduce steel cost.

7.   Low duty furnace wall decrease the total transportation weight.

8.   Simple stucture design, low breakdown rate, easy operation and maintain.

9.   Beautiful outer pack.

*0. Extensive fuel adaptability, such as wood chips, bamboo splints, biomass pellets, anthracite coal, etc. solid fuel.