Water tube boilers, the gas production is basically above 20 tons / hour. At present, the SZS type gas water tube boiler is the best seller. Compared with the fire tube boiler, it has no large diameter drum in the structure, and the flexible curved water tube replaces the straight tobacco tube, which not only saves metal, but also creates conditions for increasing boiler capacity and steam parameters.
Advantages of water tube boilers:
1. The boiler of the water tube boiler is placed outside the cylinder. The volume of the furnace can be large or small, which can meet the requirements of combustion and increase of evaporation.
2. The water tube boiler drum is generally not directly heated, and the tube containing the water vapor is placed in the furnace and the flue as a heating surface, and the heat transfer performance and safety performance are significantly improved.
3. The preheating, steam and steam superheating of the water tube boiler water is completed in the economizer, the water wall and the convection tube bundle, and the superheater on the heating surface.
4. The water vapor system, combustion system and auxiliary system of the water tube boiler are more complicated, but the structure of the single pressure-bearing parts of the water tube boiler is relatively simple.
5. Water tube boilers require higher water quality and higher operation, operation and management level because water preheating, steam water and steam superheating are all completed in the pipe and pipe scaling is difficult to remove.
Disadvantages of water tube boilers:
1. The structure is complex, the manufacturing cost is much higher than that of the fire tube type, and the troubleshooting is also very difficult.
2. The influence of scale is quite great and the water quality is strict.
3. Because of the small capacity of steam drum and water drum, it is easy to cause co-evaporation of steam and water, and produce high humidity steam.
4. The water tube is in contact with high temperature combustion gas for a long time and is easily damaged.
5. The steam storage is small, so the pressure changes greatly.
