What are the characteristics of various structural boiler?

The basic structure of the boiler shell boiler is double jacket structure. The outer cylinder is called the shell, the inner cylinder called furnace (fire tube), inside and outside the cylinder between the ring space water, and the inner cylinder is the combustion chamber. When the water vapor medium pressure, the shell by the internal pressure, the furnace under external pressure. Shell boiler is divided into two kinds of vertical and horizontal. Currently used fuel, gas boiler is WNS horizontal internal combustion boiler shell.

Shell boiler has the following common features:

(1) A "pot" of water and a "stove" of fire are contained in a shell - the shell;

(2) metal furnace (furnace) small volume, surrounded by water, a large degree of water-cooled, poor combustion conditions, you must burn high-quality fuel;

(3) less heating surface, evaporation or thermal power is small, often installed pipes or fireworks to increase the heating surface and boiler capacity;

(4) Shell shell diameter larger, more holes, irregular shape, the internal part of the heat and not connected by the hot part of the temperature and thermal expansion of different degrees, and thus poor housing safety;

(5) boiler system is relatively simple, easy to transport and installation, operation management and inspection and maintenance.

Water pipe boilers occupy a major place in modern boilers. Compared with the boiler shell boiler, the structure has completely different characteristics:

(1) The hearth is placed outside the metal cylinder shell, usually bricklaying structure. "Furnace" is not subject to "pot" restrictions, the size can be larger and smaller, to meet the requirements of combustion and increase evaporation;

(2) Large core containers placed in the hearth and in the flue as main heat receiving surfaces, water storage and connecting pipes to accommodate the water vapor pipes - The drums are generally not directly heated by the flame, and the heat transfer performance and safety performance of the boiler

Have significantly improved;

(3) Water preheating, vaporization and steam overheating are done in different heated surfaces, called economizers (preheating), waterwalls and convection tubes (vaporization) and superheaters (steam overheating), respectively;

(4) The system of pot, combustion system and auxiliary system are more complicated, but the structure of a single pressured element and component is relatively simple;

(5) The water quality and operation of the operating level are demanding. The overall structure of water-tube boiler type "D" type, "A" type, "O" type, inverted "U" type and other species.

Horizontal fire tube boiler also known as horizontal fast boiler. Is currently the most common use of our country, the largest number of industrial boilers. The utility model is based on a horizontal external pyrotechnic boiler and is provided with water cooling walls on both sides and the back of the boiler shell to form an external furnace and form a combination of fire and water pipes. Horizontal water tube fire boiler has the advantages of compact structure, manufacturing and transportation, convenient installation, quick fire start and high thermal efficiency when used. But its shell is directly heated by the flame, prone to drum kits and other defects; after the tube plate on both sides of the temperature difference, poor cooling conditions, easy to crack. At present, this boiler has some improved structure.