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 this?
Chimney - a vertically located device through which combustion products are discharged into the atmosphere. The principle of operation of this element is based on the thrust force, due to which the masses of gas move from the inlet to the outlet pipe.
The cross section of the device can be oval, polygonal, round. The 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 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 an end element. Several chimneys can be connected to it at once.
Regardless of the height of the chimney, its main task is to remove the products of combustion of fuel and gases. Together with them, soot, soot, ash 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 (the walls) must be made even, smooth, without cracks and potholes.
The second important task is to ensure normal traction. The latter directly correlates with 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 natural draft, in other words, the replacement of hot air with cold air. Based on the foregoing, the thickness of the pipe must be at least one and a half bricks, and the height must be at least 5 meters.
Unusual uses for tall pipes include use as a holder for mobile phone and TV antennas, and sometimes as power pylons.
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:
- Neck for connection to the source from which it is required to divert gas.
- Smoke damper(s).
- Metal cap.
Let's look at the main classifications of the subject of our conversation.
- Exhaust. These are flue ventilation pipes for industrial facilities, which remove processed gas-air products from equipment. The latter are characterized by high humidity and low heating temperature (up to 80 ° C).
- Smoke. They remove combustion products that appear during the combustion of various fuels in power units, boiler houses, as well as gases emitted during production processes, whose temperature varies between 80-500 ° С.
According to the main material:
- Reinforced concrete - prefabricated and monolithic.
- Made of engineering plastics.
- Metal chimneys.
According to the principle of fulfilling its task:
- Devices that fully provide draft, creating the necessary air flow into the working area of the furnace, furnace of the unit and other technical equipment.
- Pipes in which the release of gases and other harmful products of combustion into the atmosphere is possible due to forced draft, which creates a special equipment.
I must say, many chimneys for boiler houses, industrial facilities combine these two principles.
By type of structural diagram:
- 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 shaft.
The degree of impact of combustion products on load-bearing structures depends on the above features.
By carrier type:
- For wall mounting.
On the use of insulation material:
By design features (classification is largely a consequence of everything said earlier):
- Brick. These are unlined and lined (acid-, refractory materials, brick) pipes.
- Monolithic reinforced concrete. The lining can be made of polymer concrete, clay bricks, acid-resistant raw materials, and be pressed. The structure may also have a lining and a ventilated gap, one or more internal flues made of ceramic, metal, engineering plastics, precast flint.
- Precast concrete. Can be lined or unlined.
- Metal. Stretched or free standing. With lining and without it. With one or more gas vents lined with engineering plastics or metal.
- Metal pipes-towers made of a supporting lattice frame. The latter supports both one and several gas exhaust shafts made of engineering plastic or metal.
- Guarded, self-supporting pipes (made of structural plastics or metal) in a supporting metal frame, which are installed on the structures of boiler units, buildings or industrial production facilities.
To havea more complete picture of the operation of chimneys, we will analyze in detail the individual varieties of these devices.
In fact, industrial type pipe building began with this type. The height limit for brick objects is no more than 90 meters. They are being built to remove gases, combustion products of a very wide temperature range, not excluding high ones.
Today, a wide variety of linings and design solutions are used in the construction of brick pipes. This allows the elements to be used in the following industries:
- urban and rural boiler houses;
- chemistry and other and production.
Brick chimneys are the most common in Russia today.
For this variety, we can distinguish two main types:
- Polyvinylidene fluoride and polypropylene constructions. They are distinguished by ease of assembly, wear resistance and absolute resistance to corrosion. Only the operating temperature of such a pipe is not more than 120 ° С.
- Fiberglass structures. The maximum operating temperature of these chimneys is 180 °C.
Precast concrete pipes
As a rule, these objects have a small height - typical projects are 30 and 35 meters. As an exception - 60 m. There are also experimental objects on the territory of our country with a height of 75 meters. Made from heat resistant concrete. Designed for smallboiler houses.
Precast concrete structures are operated without lining. But if there is exposure to high temperatures or aggressive escaping gases, then 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, towering 180-250 meters above the ground. Only a few have a height of 330 meters. One monolithic reinforced concrete chimney in Russia - 370 meters.
Innovation in the field of pipe construction. Modern modular ceramic structures are designed for a service life of up to 120 years!
They also have a reduced wall thickness, which leads to their lower weight. The operating temperature of such a chimney is 600 °C. Therefore, it can be operable when directly ignited for 1.5 hours.
A distinctive feature is moisture and gas impermeability. Guarantee the tightness of the gas outlet shaft, do not filter either condensate or the aggressiveness of the discharged combustion products, which allows the pipe to operate under excessive pressure with a high throughput.
For metal pipes it is possible to make any lining. There are also wide variations in the use of protective paintwork materials.
The main difference of this constructive solution is a clearseparation of technological and bearing 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 the exhaust shaft, fixed in this frame, takes on the impact of combustion products, bringing them out into the atmosphere.
It must be said 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.
Such boiler chimneys (gas or liquid fuel) can be used both in private construction and industrial facilities. The mast structure consists of a supporting metal tower (three-, four-mast) and gas outlet shafts attached to it.
Pipe elements are quite easy to transport to be assembled directly on site. Parts are mounted like a designer; they are fastened together with screws and nuts. Sometimes the assembly process takes no more than a few hours!
The basis for the construction is a concrete pad. The maximum height is 28 meters.
Such structures are attached to the wall of the building with clamps with an anchor coating. In this case, no foundation or supporting structures are needed, which significantly reduces costs.
The device is installed both inside and outside the house. Suitable for different types of boilers - both gas and liquid fuel.
Constructions of this type are designed to display productsprocessing of gaseous, liquid and solid fuels from the boiler. Self-supporting pipes come in two varieties - multi-barreled and single-barreled. The big advantage of such elements is their small weight, which simplifies the installation process in both a private house and an entire enterprise.
Another advantage of this type of chimneys is that they do not filter combustion products and condensate, which positively affects the operating pressure.
In this case, the first step is to install the outer shell of carbon steel type. Pipes made of stainless material with a thermal insulation layer are inserted into it.
The whole structure is fixed in the anchor basket, which is already poured into the foundation. Connections from several boilers can lead to the flue.
Common in seismologically active areas. In this case, an anchor basket is poured into the foundation, on which the truss structure is fixed. Throughout this complex, from one to six chimneys can be installed.
Furnace structures inside themselves are further divided into several types:
- Indigenous. Located near the heating device, have their own foundation.
- Suspended. Typical for small buildings - installed outside the house, so as not to clutter up the space inside.
- Packed. 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 particularlycommon due to installation complexity.
In order for the device to function properly and perform its tasks, it is necessary to calculate the chimney before installation. Aerodynamic performance is especially important. A typical project consists of the following parts:
- Calculating the height of a structure.
- Calculate structural strength.
- Heat engineering calculations.
- Calculate the stability of the chimney.
Correctly made calculations help to 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.
Calculation of the pipe height is carried out taking into account current sanitary and environmental standards, terrain features, weather conditions, temperature of the output combustion products.
The basic design requirements are as follows:
- Resistance to temperature extremes.
- Fire safety.
- Resistant to various acids, corrosion.
- Moisture resistance.
- Static stability.
Caring for your device
Both domestic and industrial chimneys need comprehensive and timely care:
- Cleaning before and after the heating season.
- Examinations to identify newly appeared defects.
- Checking connections - sleeves,nozzle.
- Replace grout every 5-10 years.
- Prophylactic cleaning - removal of soot, soot and ash from the inner walls.
Main device issues
There are certain problems that are common to both industrial and domestic chimneys:
- The accumulation of deposits from the 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.
- Another problem stands out for industrial buildings. A high pipe should be visible to aircraft at any time of the day. To do this, it is painted in contrasting stripes (marking white and red), and at night it is lit with red signal lights or even special lights.
So we have dismantled the features and characteristics of our subject of conversation from various angles. Most of all, attention was paid to the classifications of pipes, of which there are many, as well as the description of their individual varieties.