The device, the classification of which we will discuss, is an important structural element of residential and non-residential buildings. This is a chimney. We will analyze in detail the design of the object, its varieties, characteristics, important requirements for it.
What is it?
A chimney is a vertically located device through which combustion products are discharged into the atmosphere. The principle of operation of this element is based on traction force, due to which the mass of gas moves from the inlet to the outlet pipe hole.
The cross section of the device can be oval, polygonal, round. A chimney is built only from non-combustible materials - brick, ceramics, metal, natural stone, asbestos cement, metal. The height of the device (on an industrial scale) can reach hundreds of meters.
If we have before us a system that uses a chimney - a horizontal, inclined, or vertical channel for removing gas from burners, stoves, stoves, then here the chimney will be considered the end element. Several chimneys can be connected to it at once.
Device purpose
Regardless of the height of the chimney, its main task is to remove the products of combustion of fuel, gases. Together with them, soot, soot, ashes and smoke are also removed. So that these elements do not settle on its inner walls and do not impede the fulfillment of the main purpose, they (walls) must be made even, smooth, without cracks and potholes.
The second important task is to ensure normal traction. The latter is directly related to the thickness and height of the chimney. Since the temperature of the combustion product at the outlet sometimes exceeds 100 ° C, this allows you to create a natural draft, in other words, the replacement of hot air with cold. Based on the foregoing, the thickness of the pipe should be at least one and a half bricks, and the height should be at least 5 meters.
Among the unusual applications for high pipes is the use of mobile communications and TV antennas, and sometimes power transmission towers , as a holder .
Materials and construction
The most common materials for these devices in our country are brick, concrete and metal.
A typical brick chimney consists of the following elements:
- A neck to connect to the source from which you want to divert gas.
- Smoke valve (valves).
- Riser.
- Otter.
- Slope.
- Neck.
- Headband.
- The cap is made of metal.
Chimney classifications
Let's look at the main classifications of the subject of our conversation.
For technological purposes:
- Exhaust. These are chimney ventilation pipes for industrial facilities, exhausting gas and air products that have been processed. The latter are characterized by high humidity and a low heating temperature (up to 80 ° C).
- Smoke Combustion products appearing during the combustion of various fuels in power units, boiler houses, as well as gases released during production processes, whose temperature varies between 80-500 ° , are removed.
According to the main material:
- Brick.
- Reinforced concrete - prefabricated and monolithic.
- Combined.
- Ceramic.
- Of engineering plastics.
- Metal chimneys.
By the principle of completing its task:
- Devices that fully provide traction, creating the necessary air flow into the working area of the furnace, furnace unit and other technical equipment.
- Pipes in which the discharge of gases and other harmful products of combustion into the atmosphere is possible due to forced draft created by special equipment.
I must say, many chimneys for boiler rooms, industrial facilities combine these two principles.
By type of constructive scheme:
- Having a gas outlet channel, the elements of which at the same time become the supporting structure of the pipe itself.
- Having a separate separate gas outlet trunk.
The degree of impact of the products of combustion on the supporting structures depends on the above features.
By type of carrier element:
- Mast.
- Self-supporting.
- For wall mounting.
- Farm.
- Columned.
On the use of insulation material:
By design features (classification is largely a consequence of everything said above):
- Brick. These are non-lined and lined (acid-, refractory materials, bricks) pipes.
- Monolithic reinforced concrete. The lining can be made of polymer concrete, clay brick, acid-resistant raw materials, and be clamped. The design can also be observed lining and ventilated clearance, one or more internal gas exhaust trunks made of ceramics, metal, structural plastics, precast silica concrete.
- Prefabricated reinforced concrete. They can be with or without lining.
- Metal. On stretch marks or free-standing. With and without lining. With one or more flue gas trunks made of structural plastics or metal.
- Metal tower pipes made of a supporting lattice frame. The latter supports both one and several gas exhaust trunks made of structural plastic or metal.
- With extensions, self-supporting, in a supporting metal frame pipes (from structural plastics or metal) that are installed on the structures of boiler units, buildings or industrial facilities.
In order to have a more complete picture of the operation of chimneys, we will analyze in detail the individual varieties of these devices.
Brick pipes
In fact, this type of industrial type began pipe-making. The maximum height for brick objects is not more than 90 meters. They are erected for the removal of gases, combustion products of a very wide range of temperatures, not excluding high ones.
Today, a wide variety of linings and structural solutions are used in the construction of brick pipes. This allows the use of elements in the following industries:
- petrochemistry;
- urban and rural boiler rooms;
- metallurgy;
- chemistry and others and production.
Brick chimneys are the most common in Russia today.
Plastic pipes
For this variety, we can distinguish two main types:
- Polyvinylidene fluoride and polypropylene structures. They are distinguished by ease of assembly, wear resistance and absolute resistance to corrosion. Only here is the working temperature of such a pipe - no more than 120 ° C.
- Fiberglass construction. The maximum operating temperature of these chimneys is 180 ° C.
Precast Concrete Pipes
As a rule, these objects have a small height - typical projects of 30 and 35 meters. As an exception - 60 m. There are experimental facilities 75 meters high on the territory of our country. Made of heat resistant concrete. Designed for small boiler rooms.
Prefabricated reinforced concrete structures are operated without lining. But if exposure to high temperatures or aggressive gases is observed, they can be lined to the full height or partially.
Monolithic reinforced concrete pipes
The most common applications are energy, industrial enterprises. The average height of structures in Russia is 90-150 meters. You can count a hundred of these pipes, rising above the ground by 180-250 meters. Only a few have a height of 330 meters. One monolithic reinforced concrete chimney in Russia is 370 meters.
Ceramic pipes
Innovation in the field of pipe construction. Modern modular ceramic constructions are designed for a service life of up to 120 years!
They also differ in reduced wall thickness, which leads to their lower weight. The working temperature of such a chimney is 600 ° C. Therefore, it can be operational with direct fire for 1.5 hours.
Metal pipes
A distinctive feature is moisture and gas impermeability. They guarantee the tightness of the exhaust pipe, neither condensate nor the aggressiveness of the exhaust products are filtered, which allows the pipe to work under excessive pressure with a high flow rate.
For metal pipes it is possible to make any lining. Variations in the application of paint and varnish protective materials are also widespread.
Pipe towers
The main difference between this design solution is a clear separation of technological and supporting functions of the elements of the object. Let's figure it out. The lattice tower here plays the role of a load-bearing structure, and a gas outlet trunk, fortified in this frame, takes on the effects of combustion products, bringing them out into the atmosphere.
I must say that chimneys in lattice frames are the most economical in terms of material consumption. In addition, they can be erected in the shortest possible time.
Mast pipes
Such boiler chimneys (gas or oil-fired) can be used both in private construction and in industrial facilities. The mast structure consists of a supporting metal tower (three-, four-mast) and gas outlet shafts attached to it.
Pipe elements are fairly easy to transport to assemble directly on site. Parts are mounted like a designer; they are fastened together by self-tapping screws and nuts. Sometimes the assembly process takes no more than a few hours!
The basis for the construction is a concrete pillow. The maximum height is 28 meters.
Wall pipes
Such structures are attached to the wall of the building with clamps with an anchor coating. In this case, the foundation or supporting structures are not needed, which significantly reduces costs.
The device is installed both inside and outside the house. Suitable for different types of boilers - both gas and oil-fired.
Self-supporting pipes
Designs of this type are designed to remove the products of the processing of gaseous, liquid and solid fuels from the boiler. Self-supporting pipes come in two varieties - multi-barrel and single-barrel. A big plus of such elements is their small mass, which simplifies the installation process in a private house or the whole enterprise.
Another advantage of this type of chimneys is that they do not filter combustion products and condensate, which positively affects the working pressure.
Column pipes
In this case, the first step is to install an outer shell made of carbon-type steel. Pipes made of stainless material with a heat-insulating layer are inserted into it.
The whole structure is fixed in an anchor basket, which is already poured into the foundation. Connections from several boilers can lead to the flue.
Truss pipes
Distributed in seismologically active areas. In this case, the anchor basket is poured into the foundation, on which the truss structure is fixed. Throughout this complex, one to six chimneys can be installed.
Chimneys
Furnace designs within themselves are divided into several types:
- Indigenous. Located near the heating device, have their own foundation.
- Outboard. Characteristic for small buildings - they are installed outside the house so as not to clutter up the space inside.
- Mounted. The most popular type. The pipe is installed on the heating device itself.
- Wall In this case, the chimney is built into the wall of the house at the construction stage. This type is not particularly common due to the complexity of installation.
Design design
In order for the device to function properly and perform its tasks, before installing it, it is necessary to calculate the chimney. Aerodynamic performance is especially important. A typical project consists of the following parts:
- Calculation of the height of the structure.
- Calculation of structural strength.
- Thermotechnical calculations.
- Calculation of the stability of the chimney.
Correctly performed calculations help determine the minimum throughput of the passage of combustion products through the pipe. The result of the entire project is clear recommendations on the height and diameter of the structure, the selection of its necessary elements.
The calculation of the height of the pipe is carried out taking into account current sanitary and environmental standards, features of the terrain, weather conditions, temperature of the exhausted combustion products.
The basic design requirements are as follows:
- Resistance to temperature extremes.
- Fire safety.
- Resistance to various acids, corrosion.
- Gas tightness.
- Moisture resistant.
- Durability.
- Static stability.
Device Care
Both home and industrial chimneys need comprehensive and timely care:
- Cleaning before and after the heating season.
- Examinations to identify newly emerging defects.
- Checking the connections - sleeves, pipe.
- Replacing grout every 5-10 years.
- Sleeve.
- Preventive cleaning - removing soot, soot and ash from the inner walls.
The main problems of the device
There are certain problems that are characteristic of both industrial chimneys and home ones:
- Accumulation of deposits inside, which reduce the diameter of the section.
- Destruction of the structure itself from the outside and from the inside due to wind load, exposure to aggressive combustion products. In this case, timely repair of chimneys is required.
- For industrial facilities, another problem stands out. A tall pipe should be noticeable to aircraft at any time of the day. To do this, it is painted in contrasting stripes (marking white and red coloring), and at night red signal lights or even special lights are lit on it.
So we have analyzed from the most diverse sides the features and characteristics of our subject of conversation. We paid most attention to the classifications of pipes, of which there are many, as well as to the description of their individual varieties.