When natural exhaust does not cope with its task of removing smoke, it is necessary to install a smoke exhauster to create forced draft. Such devices are used for fireplace or stove pipes, used on boilers, and are excellent for use in a private home.
Without the use of forced exhaust, serious problems may occur if the natural draft in the chimney is disrupted. The smallest problem in this case will be the gradual clogging of the ventilation system (smoke exhaust), the most serious will be a threat to the health of people living in the building.
This device is a duct fan with an electric motor, which is mounted at the outlet of the chimney. The principle of operation of the device is simple - during operation of the fan, the draft in the chimney increases.
Simply put, this device is a forced exhaust system, but they are not designed for full exhaust. They are used only to improve (occasionally) the natural draft in the pipe, or during its repair.
For example, a fireplace smoke exhauster is started as needed - for a time when the natural draft drops to a certain value.
The rest of the time, while the traction is normal, its activation is impractical, so it simply “stands idle”.
There are several indications for the use of a fireplace smoke exhauster, which are in one way or another related to draft disturbances in the chimney pipe.
Indications for use:
Any device of this type has both a number of undeniable advantages and a number of disadvantages. This is also true for smoke exhausters.
Among the advantages of such a device it is worth noting:
List of disadvantages of using such a device:
You can use a smoke exhauster on chimney pipes for stoves, fireplaces, and various boilers ( gas and solid fuel). But there is one important condition - such a product can only be installed on chimneys in which the temperature does not exceed +600 degrees.
This also applies to heat-resistant models. Although they are designed for high-temperature operation, they are not too high (therefore they are used for a stove or fireplace, but not for industrial purposes). Moreover, +600 degrees is a very good indicator; many heat-resistant smoke exhausters are even designed for temperatures up to +350 degrees (average value).
The cost of a smoke exhauster depends on which model you are going to order and with what parameters (standard, heat-resistant). For clarity, you can demonstrate the cost of several popular models.
Approximate cost:
Installing a fan on a fireplace is quite simple and does not require any special theoretical knowledge. The first step is to calculate the direction of air flow. This information is available on the packaging with the device or in the instructions for it.
Installation is carried out from above at the mouth of the chimney pipe. Please note that it is easier to install the device on brick chimneys than on chimneys made of of stainless steel. You should also think about the power supply system to the smoke exhauster and correctly position the wire with the switch and speed mode switch.
It often happens that a newly installed stove or gas boiler does not want to burn well. This means that the reason is poor draft - the chimney was built incorrectly. And sometimes the stove, which has always been burning well, begins to act up. This means that the quality of the chimney has deteriorated. You can identify the reasons for this and fix the problem yourself.
The chimney is an indispensable part of any stove: Russian, Dutch, contrail, potbelly stove or gas boiler. The chimney removes the mixture of gases resulting from combustion from the room and ensures complete combustion of the fuel.
The correct chimney design, suitable for a specific heating device, helps it perform certain functions. Let's look at the types of chimneys for different heat generators:
When a chimney is properly designed, built and maintained, it will provide good draft.
The physical meaning of draft is a vacuum that arises due to the pressure difference in the upper and lower parts of the chimney and ensures the movement of smoke from heating device in atmosphere.
Craving can be natural or forced. In the first case, the chimney does not contain any additional technical devices, in the second - equipped with a fan, deflector, stabilizer, weather vane.
If the draft is poor, and therefore if combustion is incomplete, the stove, fireplace or gas boiler has low efficiency, smoke may occur in the room, a fire or, worst of all, poisoning carbon monoxide. This gas has almost no odor and immediately causes drowsiness, which is why the number of accidents from burning is so high.
This is why it is so important to be able to determine whether your chimney has enough draft.
There are different ways to measure traction force. Conventionally, they can be divided into “scientific” (using special instruments) and folk ones.
An anemometer, which was once called a “wind meter,” is a device for measuring the speed of movement of gases. The name comes from the Greek words ἄνεμος (wind) and μετρέω (measurement). Measurements with an anemometer can be made both with the heating device turned on and not working.
This simple device is inexpensive and quite accessible. Anemometers are:
If the anemometer shows a value between 10 and 20 Pascals, then your chimney is normal.
Since draft is caused by the difference in temperatures inside and outside the room, if we measure it in the summer, when the temperature is almost the same everywhere, we will get a lower value than in winter.
Since previously there were no specialized instruments, and thrust was somehow measured, several quite acceptable methods have been preserved that do not require any special devices:
Backdraft is an extreme case of bad draft. Smoke is not just poorly removed, but is thrown into the room due to a change in the pressure difference at the inlet and outlet of the chimney in the opposite direction.
Reverse thrust usually occurs unexpectedly. Common reasons its occurrences are:
There are several reasons for poor traction:
All these phenomena are permanent, their correction is associated with certain costs. It is more or less easy to solve the problem of a steel chimney being insufficiently high or falling into the wind pressure zone - you need to install a new piece of the pipe on the roof. Other design defects can only be eliminated by using additional mechanisms and devices.
To improve draft, devices that are mounted on the chimney are mainly used. Most of them are installed on the head of the pipe, but there are also devices that are built into the very beginning of the smoke channel.
The rotary turbine is mounted on top of the pipe, rotates and creates an air vacuum. It looks like a dome that protects the pipe from rain and pollution. Designed for boilers and conventional ventilation. Minuses:
The rotary turbine creates the necessary vacuum at the outlet of the chimney due to rotation under the influence of wind force
The weather vane also revolves around the chimney and represents the most witty and efficient design. Unlike a rotary turbine, it reacts to the direction of the wind and adopts a position in accordance with the current air flow. The grates trap the wind and create a strong vacuum in the chimney. Using a weather vane allows you to reduce the length of the pipe above the roof and increases the efficiency of the heating device by more than 20%. When used with gas boiler the weather vane prevents its spontaneous attenuation. But making such a device yourself is quite difficult: the design is quite intricate.
The weather vane not only shows the direction of the wind, but also creates the necessary vacuum at the outlet of the chimney and increases draft
Fans are used to increase draft in fireplaces and wood-burning stoves. The steel body of this device is protected polymer coating, therefore it is able to work in an environment with aggressive combustion products. The grille protects the air duct from debris. The fan has a single-phase electric motor, removed from the zone of hot air movement. This is a high-tech device with built-in temperature and air flow sensors, which themselves regulate the speed of rotation of the impeller, creating the thrust required at the moment. The work is fully optimized and automated. Big drawback - high price. It is impossible to do it yourself.
The electric fan operates in automatic mode: it turns on and off based on signals from special sensors
The draft stabilizer is built in between the firebox and the chimney. This is a valve that, when the draft increases too much, allows air from the room into the chimney, due to which the temperature of the gases in the chimney drops and the draft decreases. When the valve closes, the draft increases. The stabilizer can be manual or automatic. Pros:
The downside is that it is only suitable for heating appliances with an open pipe: for gas boilers and potbelly stoves. It's difficult to do with your own hands.
The draft stabilizer is a valve that opens or closes depending on the current draft force
A deflector is also a device attached to the end of the chimney pipe. The name comes from the Latin deflecto - to deflect, and the action is based on Bernoulli's law: air currents flow around the deflector and create a rarefied area above the pipe opening. The stronger the wind outside, the greater the draft inside. Such simple-looking models of deflectors are intelligently designed from an aerodynamic point of view. The deflector is used for solid fuel boilers, stoves and fireplaces. Depending on the model, such products cost from 1000 to 9000 rubles.
Plus - this is a relatively simple device, and it can be easily made with your own hands from a sheet of galvanized iron or stainless steel.
There are several types of deflectors. Let's look at them in more detail.
The simplest version of a deflector such as a Volpert-Grigorovich device is quite easy to make with your own hands.
Since the quality of the deflector depends on the accuracy of manufacturing, drawing up the correct drawing is the most important stage in the whole process. The dimensions were verified by scientists in a wind tunnel, and they must be followed. The parameter to start from is the diameter of the chimney channel D.
The dimensions of all parts of the deflector are set in proportion to its diameter
The deflector may not be very beautiful, but you will immediately feel its usefulness: the draft will increase by a quarter, the roof will be protected from sparks. The pipe with it can be one and a half to two meters lower.
When installing any traction booster, you will immediately feel the benefits. But done with my own hands the deflector will also create a compelling reason to make you proud of yourself.
Draft is the natural movement of air masses from any heat generator into the external atmosphere along with the removal of hazardous combustion products. If it is weak, the fuel will burn very slowly. It can also have a detrimental effect on the human body - gas pollution in the room in some cases leads to death. To create forced circulation air, install a chimney fan.
If you have any doubts that the draft in the chimney from the heating device is weak, then you should definitely check it. The simplest method is to use an anemometer. The normal indicator is a traction force of 10−20 Pa. The big disadvantage of such devices is that inexpensive devices have poor measurement accuracy. If the indicator is below 1 Pa, then they will show that the system does not remove combustion products at all. Professional devices are quite expensive. They are often used only by stove makers.
To check the chimney, you can use traditional methods:
Natural circulation of air masses occurs due to the difference between street and internal atmospheric pressure. The indoor temperature is much higher. Cold air presses on the warm from below, thereby removing it to an area with lower pressure, that is, to the street. Measurements in summer period will be less accurate.
Before we talk about using forced exhaust for a chimney, you should understand the process of removing combustion products. You also need to understand the reasons for the deterioration of draft in the chimney. All factors influencing this can be divided into three main groups:
Internal also includes the temperature and volume of air in the house, the number of oxygen consumers, and the conditions for the movement of air masses. The design of the house also affects draft. For example, installing plastic windows often impairs air circulation. This is due to the higher tightness of double-glazed windows, which reduces the volume of incoming oxygen.
External factors include outdoor air humidity, temperature, atmospheric pressure, wind currents, and air mass flow speed. Because of all this, constant changes in draft in the chimney appear. The process of removing carbon monoxide from furnaces and other heat generators should be constantly monitored.
Factors associated with chimney design include:
All these factors completely depend on the person. At the design stage, all possible problems can be taken into account. If the structure is already ready, then the deficiencies are eliminated during repairs.
You can endlessly look at three things, one of which is how the fire burns. Quite often, many people use fireplaces in decorating private homes. And some are forced to use solid fuel boilers to heat the room in winter. In any case, all this is connected with fire. It creates comfort and provides warmth. However, where there is fire, there is smoke. No system can function without a chimney. It happens that they do not quite cope with their task and there is a constant smell of smoke in the house. In this case, increasing the chimney draft using a fan will help. This is a forced removal, which will cost you a little.
If you are faced with such a problem, then you may be interested in answers to the following questions: what types of products exist, what is the difference between them, how to choose a fan for a chimney? We will look at all this further.
This is a fairly common option forced ventilation. A deflector is an aerodynamic device that is installed above the chimney. It increases draft in the chimney due to changes in air flow. The essence of its work is the pressure drop when air flows around an obstacle, as well as the principle of changing air flows. It turns out that its shape allows you to increase draft in the chimney. Made of stainless steel, they are not afraid of corrosion, resistant to acids and high temperatures.
It cannot be called a full-fledged fan, since the deflector has simple form, without working mechanisms. But, there are types of smoke deflectors designed specifically for chimneys.
In addition, weather vanes, umbrellas and similar structures are often installed on chimney pipes. But they can't do everything that a high-temperature chimney fan can do. Let's look at how they work and what makes them special.
The chimney exhaust fan is a heat-resistant electrical device. It is mounted directly on the chimney to increase draft in the chimney pipe. It is important not to confuse a chimney fan with a fireplace fan, which is needed to supply air to support combustion. Here the operating principle is different. To put it simply, a chimney fan is an electric motor with blades that forcefully pull smoke out of the chimney and direct it outside. For full operation of the fan, power supply from a 220V network is required.
In fact, a fan in a chimney to improve draft is somewhat reminiscent of a deflector, but its operation does not require wind force at all. He works constantly, doing his job perfectly. In addition, you can find economical models on sale. They operate in two modes: when there is a strong wind outside, rotation occurs naturally, without the use of electricity. And in calm weather the electric motor starts. This perfect solution for the chimney.
Such devices have found application in many areas of life. Fans are an integral part of the heating system. It is important to understand that a fully functioning and properly functioning chimney is a necessity. This is the only way to not worry about your health and the health of your family members. By installing a chimney fan yourself, you will protect yourself and your loved ones.
Here's where fans can be used:
Since smoke has a high temperature and constantly affects the structure, the chimney fan is made heat-resistant. The material can withstand temperatures up to 250 degrees. This is quite enough to serve faithfully for many years. Typically products are made from cast aluminum with a special coating. The engine has lifetime bearing lubrication and is also made heat-resistant.
As for the types of fans, it all comes down to differences in their shape and power. After all, chimneys are different, so you need to choose a device that would fit inside and have the shape of a chimney. These are the features of choosing products for the chimney. Usually the design is made in a square or round shape.
An excellent round shaped fan used for intermittent or long-term operation. Its productivity is 60 m 3 / h, with a power of 16 W. The product has a protection class of IP44. The seat diameter is 9.9 cm, and the depth is 2.5 cm. The fan produces 2.5 thousand revolutions. The product can be installed in channels with a short length. Thanks to the low noise electric motor, which has double-encapsulated ball bearings, the device can operate for as long as 30 thousand hours. In this case, the fan can be mounted both vertically and horizontally. The body consists of aluminum alloy, which cools quickly and can withstand temperatures up to 150 degrees. Warranty – 3 years. The cost is about $38.
Unlike the previous version, the fan has a square shape; as for the parameters, they are practically no different. Power is the same 16 W, performance, protection class, speed and other indicators are the same. But the mounting diameter is 9.3x9.3, with a depth of 2.5 cm. Warranty - 3 years, cost - $38.5.
The fan is also used for the chimney round section. It is much more powerful than previous options. With a power of 18 W, the device has a productivity of 240 m 3 / h. Bore diameter – 12 cm. Protection class IP44.
The model has different section along the axis of the fan, which allows it to be adapted to conventional air ducts. The material is heat-resistant, and the engine will last 30 thousand hours of operation. Manufacturer's warranty – 3 years. Cost – $90. Having bought this exhaust fan onto the chimney pipe, you can forget about weak draft.
The issue of increasing draft in the chimney is very important. Not only your comfort, but also your safety depends on this. Therefore, you should not neglect the lack of a chimney fan in your home. It is better to spend money and buy a device than to constantly smell smoke in the room. It's safe to say that you won't regret your decision later.
Reduced draft can lead to combustion products flowing back into the room and carbon monoxide poisoning. To increase the traction force, special devices are used - amplifiers (stabilizers, fans, deflectors). You can buy them or make them yourself.
Initially, it is necessary to inspect the pipe for clogging with soot or other foreign objects (a clean stove chimney, where the soot layer is no more than 2 mm). Then you should check the draft using an anemometer and compare the indicator with the norm.
One of the factors affecting draft is incorrectly selected chimney metric indicators:
Factors affecting draft also include leaks in the chimney: missing elements, fallen bricks, cracks, gaps. They create additional circulation and air flow. Experts will tell you how to improve draft in a chimney, and you can also independently find a large amount of information about the methods and devices used.
To make a deflector with your own hands, you will need several sheets of stainless steel 1 mm thick, grinder, welding machine, a clamp for the diameter of the chimney, heat-resistant sealant and other tools.
Schemes and drawings of the deflector can be found on the Internet, drawn or printed on paper and transferred to a sheet of metal. Afterwards you need to cut out the elements, bend them into the desired design and weld at the joints. Using a clamp, the structure is attached to the top of the chimney pipe.
You can make an automatic stabilizer yourself, for this you will need stainless steel sheet 8-10 mm thick, steel rod, welding machine, grinder. Having prepared the stabilizer diagram in advance, cut out a piece of steel sheet and twist it into a pipe, then weld and grind the joint. Then make a hole for the limiter equal to 15% of the diameter of the stove chimney pipe.
Two through holes are made in the pipe, into which a steel rod is placed, fixed on one side with screws, and on the other, 10 cm of its length is left and the handle is attached. Then a limiter is welded, which will subsequently close the pipe opening. Install the stabilizer in the intermediate section of the chimney and use clamps on both sides.
A brick chimney chimney is often installed; it is also used for stoves. The fan requires an additional connection to the power supply; this fact is not always possible due to safety precautions.
Using a fan as a draft amplifier is important for narrow stove chimneys, where natural aerodynamic indicators are very weak, there is a need to increase these indicators. There are models of fans that, in addition to running on electricity in strong winds, rotate due to mechanical rotation by the flow.
20.09.2017
3117
Pechnik (Moscow)
Fans to enhance fireplace draft allow you to improve the performance of both wood-burning and gas heating units. Such designs have a simple and mostly standard structure, however, despite this, the choice of such an installation should be approached with all responsibility and knowledge. You can get acquainted with all the most accurate and up-to-date information on this topic from the materials presented below, as well as by watching the video in this article.
If you don’t know how to increase the draft of a fireplace, we recommend installing a special fan-amplifier. This design has the following advantages and operational advantages:
Important: before increasing the draft in the fireplace, you will need to read the instructions provided by the manufacturer in as much detail as possible and during installation, as well as further operation, comply with all requirements and rules in order to avoid breakdowns and deterioration in the operation of the heating unit.
Interesting to know: if there is no draft in the fireplace, such fans will help solve this problem. However, they can only be used after the initial problem has been resolved and the furnace has been diagnosed by a specialist.
The operation of smoke exhausters is allowed under the influence of temperatures up to 250 degrees, and the design itself has reliable protection against corrosion, damage and rust, due to the presence of a special coating with a composition based on epoxies.
You can learn more about the various variations and models by looking at the photo selection presented in this article.
If you do not know what the draft in the fireplace depends on and for what reasons it can worsen, it is important to know about a number of the most common reasons, which are as follows:
Interesting to know: in order to perform diagnostics yourself, you just need to turn off all heating system and measure the amount and layer of soot and soot accumulated on the walls of the chimney. The thickness of such a layer should not exceed 2-3 millimeters.
In order to establish the operation of the traction mechanism, one of the following options can be applied in practice:
Cleaning and maintaining the product is quite complex and labor-intensive process
Important: make sure that the pressure in the inside of the chimney varies from 10 to 20 Pa. In order to determine this criterion, it is recommended to use special devices, for example, you can use an anemometer, the price of which depends on the chosen model and manufacturer.
Interesting to know: the instructions for extending the chimney say that the optimal total length of this element should not be less than 5-7 meters, depending on design features and number of floors of the house. In this case, knees and narrowings should occur as rarely as possible.
Depending on your wishes and individual characteristics heating installation, you can buy and install one of the following designs:
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Variety |
Description and features |
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Deflector
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It is distinguished by its strength, durability and resistance to rust and corrosion. The installation acts as a reflector or an element projecting the direction of air flows. Traction force increases due to the reflection of flows from the roof and side walls. Disadvantages include the ineffectiveness of the fan in calm conditions. However, in this case, the capsizing of such a device is completely excluded, even in very strong, squally and gusty winds. The main selection criteria are compliance with the chimney diameter and calculation of the wind load. |
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One of the simplest and inexpensive options. Its functionality and the influence of traction force directly depend on the intensity of the wind. The design consists of a head and a wing with small dimensions. The design is also complemented by a special blade, which fixes and secures the weather vane to a given section of the chimney pipe. The weather vane is most often used to increase the level of draft in solid fuel boilers working on simple logs or purchased briquettes. |
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Rotary turbine
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The work of such mechanical means carried out by rotating turbines from wind flows. Due to the presence of special attachments built into the design, rotation is carried out exclusively in one direction, regardless of the direction of the wind itself. The advantages of this type include high-quality protection against various dirt, leaves, foreign objects and precipitation getting into the inside of the chimney. Such amplifier fans are capable of removing air efficiently, which is especially important during the non-heating season. Suitable for solid fuel and gas boilers with a maximum permissible temperature limit of 250 degrees. |
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Electric smoke exhauster
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This variation is intended for stoves and fireplaces running on solid fuel. The advantages of such devices include their versatility in operation (in conditions with exposure to high temperatures, education large quantities condensate, soot and other combustion products). The maximum permissible temperature for such devices has a limit of 800 degrees. Work and operation are carried out using special temperature sensors, which, if necessary, can both slow down and increase the fan rotation speed. |
To assemble we will need to use:
Assembly instructions.
