Важный атрибут для эффективной работы solid fuel boiler and creating the required conditions for fuel combustion in it - well-mounted chimney, otherwise the unit will not have cravings that are needed to remove the products of combustion.
The key criterion for the quality of the chimneyboiler is a great traction. It is estimated based on the speed of the flue gas through the chimney. Traction depends on the roughness of the surface, the height of the chimney, the internal cross section and the difference in ambient air temperature and combustion products. It is necessary that the chimney is fire resistant, resistant to high temperatures and equipped according to fire safety regulations. Since the cross section for different boilers is not the same, the diameter of the chimney for a solid fuel boiler should be selected in accordance with the technical passport (instruction) provided by the manufacturer of the equipment.
So what is a thrust?Traction - a characteristic of the chimney, reflecting the speed of movement in it of flue gases. It appears due to the difference in temperature (heat tends up) and pressure between the street (atmosphere) and the room in which the boiler is installed. It should also be clarified that in addition to the qualitative characteristics, the draft also has a quantitative one - this parameter is influenced to a greater extent by the diameter of the chimney for a solid fuel boiler. At the same time, the thrust itself is more dependent on the design (height, fresh air, turns, corners).
In absolutely all chimney systems, the thrust is determined by several constant factors: wind temperature, flue gases; temperature difference inside and outside the room.
The warmer the room and the colder it is, thethe best traction will have chimneys for solid fuel boilers. This can be explained by the fact that the density of cold air is greater than that of warm air, which means that warm air has a lower pressure of a gas column. This factor ensures the occurrence of a pressure difference outside and inside the pipe. If the building is untight, then at the foot of the structure, due to the pressure difference, an air stream appears that is directed inward. At the same time, warm air is forced out and out through the opening at the top of the building, and cold air is inside due to the holes inside the building. Natural air ventilation occurs.
It must be borne in mind that the properties of smoke are notthey are constant, because the combustion in solid fuel boilers is uneven, respectively, the temperature of the flue gases varies in a fairly considerable range (in coal-fired boilers - 400-600 ° C, and in wood-burning 70-300 ° C). The temperature of the smoke increases sharply when the boiler is ignited and decreases after the operation starts in the standard operating mode. This also affects traction.
The length of the chimney also plays a significant role forthrust. In other words, warm chimney gases, when they rise in straight sections, are gaining a certain speed, and this provides an increase in the flow of flue gases through the chimney. There is also a definite formula that proves the dependence of thrust on the smoothness of the walls, cross-section and length of the chimney, the temperature both in the street and in the room.
The next important thing is the installation of the chimney.The smaller the number of narrowing, horizontal sections, turns, the better the pull will be. This is due to the fact that gases from the boiler go up the helix in a spiral upward, while at each of the bends the course of the flue gases changes, and their ordinary mixing takes place. However, the chimney, which has a roughness of the walls, protrusions or bends creates resistance to the flue gas turbulence formed in it.
Making a conclusion from the above, we can say thatthe best option of the chimney is round, cross-section, with smooth walls. If it is not possible to mount such a structure, it can be made rectangular, square or oval, the corresponding section. By the way, in the corners of the chimney having a rectangular shape, turbulence is formed, and this worsens the cravings and contributes to the accumulation of soot in the chimney.
In the there are exceptions.For example, a temporary weakening of the thrust, reverse thrust often occur in the summer, when temperature and temperature changes in the street and in the house. Tipping or blowing of the thrust also happens. The chimney device plays an important role in these problems.
Anemometer - a special instrument for measuring thrust.It is digital and analog. It is usually used by inspectors of the relevant authorities. In everyday life, a method with a deviation of a sheet of paper is often used, but it does not provide accurate results, but simply indicates the presence or absence of traction as such.
You can isolate several important facts that indicate the level of quality traction:
If, during the operation of the boiler, the thrust is too weak, and the flame becomes red, smoke curls, the gate is not useful, you should focus on the following nuances:
soot:the question of its presence is ambiguous, it all depends on the design of the boiler and the type of fuel, but in any case, before the start of the season should check the audit holes.
Chimneys should be performed only from high-quality and fireproof materials.
The following types of chimneys are distinguished:
This material is for laying a smoke channel.used for a long time. Brick chimneys for solid fuel boilers can be connected to the boilers at a given height and allow to skirt small obstacles. However, there is one drawback: the classical scheme of the chimney made of this material suggests that it will have too much mass and size, and this will require a lot of effort. It should also be borne in mind that the brick can not withstand temperatures above 500 ° C.
The complete arrangement of the brick chimney, having a length of 10 m and a width of 140 mm, with asbestos-cement inlays is from 23,300 rubles.
Such chimneys for solid fuel boilersmade of stainless and black steel. Structures made of black steel are unstable to aggressive environment, so they are undesirable to use. With the continuous operation of the boiler, such a chimney pipe, the price of which is relatively low, will very quickly become unsuitable for use and fire hazardous to your home.
The cost of pipes depends on the steel grade, whichused for their manufacture. So, 1 m of the pipe from the most inexpensive corrosion-resistant steel with a diameter of 115 mm has a price of 400 rubles. A similar pipe made of steel grade AISI 439 with the addition of titanium is already from 800 rubles / m.
Excellent choice for solid fuel boiler. Ceramic flues have the following properties:
Such chimneys are quite rare, theythey are characterized by low thermal inertness, a rather extravagant appearance and complete absence of corrosion. Such a chimney pipe, the price of which is quite high, is not available to everyone. It is necessary to take into account not only the high cost of the material, but also the high cost of installation work on this chimney.
