Strengthening the draft in the chimney with a fan. Forced exhaust for a chimney - an overview of methods

Draft is the natural movement of air masses from a heat generator into the external atmosphere, along with the removal of hazardous combustion products. If it is weak, then the fuel will burn very slowly. It can also adversely affect the human body - the gas contamination of the room in some cases leads to death. To create forced circulation air, install a fan for the chimney.

Methods for measuring traction force

If there is any doubt that the draft in the chimney from heater weak, it is necessary to check. Most in a simple way considered survey using an anemometer. A normal indicator is a traction force of 10-20 Pa. A 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 folk methods:

How to install a smoke exhauster

The natural circulation of air masses occurs due to the difference between outdoor and indoor atmospheric pressure. The room temperature is much higher. Cold air presses on the warm from below, thereby removing it to a zone with less pressure, that is, to the street. Summer measurements will be less accurate.

Reasons for poor gas removal

Before talking about the use of forced exhaust for the 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:

1. 1. Indoor conditions.
2. 2. External factors.
3. 3. The design of the chimney.

Internal also includes the temperature and volume of air in the house, the number of oxygen consumers, the conditions for the movement of air masses. The design of the house also affects the traction. For example, installation plastic windows often impairs air circulation. This is due to the higher tightness of double-glazed windows, which reduces the volume of incoming oxygen.

To external factors include the humidity of the air in the street, its temperature, atmospheric pressure, wind currents, the speed of the flow of air masses. Because of all this, there are constant changes in draft in the chimney. The process of removing carbon monoxide from furnaces and other heat generators should be constantly monitored.

Factors related to chimney design include:

1. 1. The location of the structure. The chimney can be located outside near the wall or inside the room.
2. 2. Pipe length and number of turns.
3. 3. The quality of the surfaces of the inner walls of the channel. A large amount of soot narrows the chimney, which is the main cause of poor draft. On rough flue pipes, it accumulates more actively.
4. 4. How high is the chimney relative to the top of the roof.
5. 5. Heat transfer of materials from which the chimney is made. Insulated constructions contribute to good traction.

Turbo deflector or electric fan? What to choose? Exhaust ventilation. Forced ventilation

All these factors are completely dependent on the person. At the design stage, all possible problems can be taken into account. If the design is already ready, then the shortcomings are eliminated during the repair.

Preventive measures

In order not to have to use any means to artificially increase traction, it is necessary to periodically carry out preventive actions. This will keep the chimney in good condition. The main reason for the deterioration of the circulation of air masses is the narrowing of the diameter of the exhaust opening. . Ways to deal with this phenomenon:

Back draft in the chimney

It is required to use high-temperature materials regularly (at least 4 times a month). This will prevent soot from accumulating in the flue ducts. If preventive measures are not taken, a serious fire can occur, since the ash releases a lot of heat during combustion.

Also on the market you can find specialized means. They work on the principle of thermal or chemical decomposition of soot. Thanks to regular preventive measures you can do without the hood on the chimney.

The need to install equipment for forced air circulation sometimes arises in connection with any natural causes. For example, trees in garden plot could grow strongly, because of which the direction and strength of wind flows changed. Of course, you can remake the chimney, but it is very expensive and difficult. It is better to use a forced exhaust for a fireplace or stove to create a normal draft.

Types of amplifiers

Deflectors are aerodynamic devices that are necessary to deflect the air flow. They allow you to change the traction force in any direction. The principle of operation of the fan is to suck in air and redirect it to the flue duct. The big drawback of the device is that the deflector is completely useless in calm weather.

The most popular devices are the designs of Volpert and Grigorovich. Now on the market you can find more modern models made on the basis of prototypes. The most common structures are:

1. 1. Multi-tiered.
2. 2. Round nozzles.
3. 3. Star-shaped.

When choosing such a device, you should pay attention to the material from which it is made. It is desirable that it be stainless steel, as it has high level strength and long service life.

A rotary chimney turbine is a mechanism that must be installed above the chimney. The principle of operation may be a bit like a fan, because the device uses the power of the wind to create high blood pressure in construction. Among the advantages, it is usually distinguished that the turbine protects the chimney from precipitation. The device is unable to perform its functions in calm weather.

fireplace fan

The fan must not be installed to remove combustion products from conventional stoves. The maximum allowable gas temperature is 250 degrees. These requirements are standard.

Chimney weathercocks are used to protect the chimney from the leeward side. These devices are well tolerated. precipitation, have a long service life, and also in their design there are defense mechanisms for the channel. Weathercocks also have quite serious drawbacks:

1. 1. They can't handle hurricane winds.
2. 2. They need to be lubricated regularly.
3. 3. Require constant cleaning from carbon deposits.

There are also special heat-resistant fans called smoke exhausters. They are powered by electricity, and it is recommended to mount such devices only in narrow channels. Devices are able to solve problems with weak and reverse thrust. No significant deficiencies were noted. The blower works well in any weather.

Making a device with your own hands

Often people try to solve the problem of insufficient traction by self-creation any devices. This, of course, is a rather time-consuming process, but it saves money.

To work, you will need the following tools:

First you need to create a diagram of the future device. You can do this yourself or peep from those who have already done this. Then it is necessary to accurately apply all dimensions to the galvanized sheet. The following steps should be performed in the following order:

The creation of the weather vane is completed. The device is attached to the chimney using self-tapping screws. It should not be forgotten that such structures require careful maintenance. Periodically, you need to clean them from soot and soot.

High-temperature fans are used in baths, saunas, fireplaces to maintain optimal microclimate in these rooms, removing smoke and excess moisture from the air.

This class of domestic exhaust fans is characterized by stability when operating at extremely high temperatures, they perfectly cope with their duties where other fans fail: at temperatures from 70 to 180 degrees Celsius.

Why is good sauna ventilation important? The fact is that during soaring, up to a liter of sweat can stand out from the surface of a person’s skin, which accumulates in the air, settles on the ceiling and on the walls. Breathing these fumes is not healthy at all. Excess moisture must be removed after the session so that fungus does not form on the walls.

How to choose a sauna fan?

The heat-resistant fan has a reliable housing made of glass-filled polyamide or metal.

Pay attention to the operating temperature in the product passport: for baths and saunas, fans with operating temperature above 100 degrees.

By the way, there is also the so-called "permissible" temperature, it can be very different from the "working" one. Permissible temperature shows the limits, reaching which the product will not deteriorate, but not the fact that it will be able to function normally.

Since the humidity in the steam bath is quite high, it is desirable that the high-temperature fan has additional moisture protection. electrical elements(IP protection class).

It is good that the sauna fan can function in two modes. While steaming in the sauna, it operates at minimum power so that there are no excessive drafts and electricity consumption.

As soon as the soaring is completed, the fan turns on full turns and removes accumulated moisture in the room to prevent the formation of mold and mildew.

One of the most important characteristics household chimney structures, which have a huge impact on the amount of draft formed in them, is considered to be the size cross section pipes.

With a decrease in the cross section of the channel, a noticeable decrease in draft in the chimney is observed, the degree of burnout of the energy carrier worsens, and combustion products can also enter the room.

However, an excessive increase in the cross section of the channel does not bode well for the owner of the house, since in this case it is possible to blow out the fire in the hearth strong gusts wind, as well as unhindered removal of heat into the atmosphere.

And therefore, many owners of private houses are concerned about the question: "How to stabilize or improve draft in the chimney." In order for us to give an exhaustive answer to this question, it is necessary to find out exactly what factors influence the strength of this phenomenon in the chimney.

What determines the draft in the chimney

The amount of thrust depends on the following factors:

• Its strength is greatly influenced by the condition of the inner surface of the walls of the chimney, as well as the presence or absence of soot accumulations in the lumen of the channel,
• Atmospheric pressure: the lower this parameter, the worse the draft in the chimney will be,
• humidity level,
• The intensity of wind loads,
• The pressure in the room.

It has long been noted that at low atmospheric pressure or high humidity environment, the draft in the chimney is also reduced. Often this phenomenon can be observed some time after the rain. This is due to the accumulation of moist air in the flue duct.

You can prevent the accumulation of moisture in the pipe if, when not using heating equipment, keep the stove damper slightly ajar, which will make it difficult for moist air masses to pass through it.

Quite often, the disadvantage of this parameter lies in the low pressure of the room, in which case it is quite simple to solve the problem. To increase traction, simply open the window. Sometimes cause low pressure indoors is the operation of air conditioning units in it.

In this case, to eliminate poor traction it is enough just to turn off the ventilating device during ignition of the furnace.

However, it is far from always possible to improve traction in such simple ways, since in some cases insufficient traction is due to design features flue duct and can only be solved by dismantling and reinstalling the pipe.

The issue of traction stabilization is urgent for most owners of private heating systems, and therefore the achievements of modern technological progress have come to their aid in solving this most important issue.

How to increase traction

Nowadays, many homeowners actively use various technical devices to improve traction. Forced extraction and retraction in environment combustion products is sometimes the only possible way out of this difficult situation.

Forced exhaust is possible when using devices such as deflectors, chimney weathercocks, rotary turbines, chimney fans.

If mistakes were made in the design of the smoke exhaust system, which have negative impact on the quality of traction, then installing a deflector will help solve this problem.

The deflector is a special aerodynamic device that is installed on the head of the chimney.

This device improves this parameter due to the forced deflection of air masses, while a significant decrease in pressure is observed around the pipe, due to which its improvement is observed.

Another device that helps improve draft in the chimney is rightfully considered a rotary turbine, which is a mechanical device. The operation of the turbine is based on improving the thrust in the pipe due to the force of the wind.

Regardless of the wind intensity, the turbine blades are in constant motion and rotate in a given direction, while forming a low pressure zone around the smoke exhaust structure, due to which this parameter is enhanced.

No less effective in terms of enhancing traction is the chimney weather vane. Its design features are such that they create optimal conditions for the free exit of smoke from the lumen of the pipe.

It is recommended to install the device on the leeward side, which will improve its functional characteristics and increase traction. These devices make it possible to significantly reduce the influence of air flows on the operation of the chimney structure and completely exclude the possibility of blowing out the hearth with strong gusts of wind.

The fan for the chimney duct is nothing more than an electric motor equipped with a fan, this allows you to organize the forced extraction of smoke from the chimney. A significant disadvantage of these devices is that they require the arrangement of a separate power supply line.

Now you know exactly how to improve chimney draft. And if your chimney is not perfect, then it is not at all necessary to dismantle it and spend money on reinstalling it. It is enough just to improve its performance with the help of any of the above devices.

Draft is the natural movement of air masses from a heat generator into the external atmosphere, along with the removal of hazardous combustion products. If it is weak, then the fuel will burn very slowly. It can also adversely affect the human body - the gas contamination of the room in some cases leads to death. To create forced air circulation, install a fan for the chimney.

If there is any doubt that the draft in the chimney from the heater is weak, then a check should be made. The simplest method is considered to be an examination with an anemometer. A normal indicator is a traction force of 10-20 Pa. A 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 folk methods:

The natural circulation of air masses occurs due to the difference between outdoor and indoor atmospheric pressure. The room temperature is much higher. Cold air presses on warm air from below, thereby removing it to an area with less pressure, that is, to the street. Summer measurements will be less accurate.

Before talking about the use of forced exhaust for the 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:

1. 1. Indoor conditions.
2. 2. External factors.
3. 3. The design of the chimney.

Internal also includes the temperature and volume of air in the house, the number of oxygen consumers, the conditions for the movement of air masses. The design of the house also affects the traction. 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 the humidity of the air in the street, its temperature, atmospheric pressure, wind currents, and the speed of the flow of air masses. Because of all this, there are constant changes in draft in the chimney. The process of removing carbon monoxide from furnaces and other heat generators should be constantly monitored.

Factors related to chimney design include:

1. 1. The location of the structure. The chimney can be located outside near the wall or inside the room.
2. 2. Pipe length and number of turns.
3. 3. The quality of the surfaces of the inner walls of the channel. A large amount of soot narrows the chimney, which is the main cause of poor draft. On rough flue pipes, it accumulates more actively.
4. 4. How high is the chimney relative to the top of the roof.
5. 5. Heat transfer of materials from which the chimney is made. Insulated constructions contribute to good traction.

All these factors are completely dependent on the person. At the design stage, all possible problems can be taken into account. If the design is already ready, then the shortcomings are eliminated during the repair.

How to choose a chimney fan

You can endlessly look at three things, one of which is how the fire burns. Quite often, in the arrangement of private houses, many people use fireplaces. And someone is forced to use solid fuel boilers to heat the room in winter. In any case, it's all about 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 the smell of smoke is constantly present in the house. In this case, increasing the draft of the chimney with a fan will help. This is a forced withdrawal, which will have to be spent a little.

If you are faced with such a problem, then you may be interested in answers to such questions: what types of products exist, what is the difference between them, how to choose a chimney fan? We will consider all this further.

Hood deflectors

This is a fairly common option. forced ventilation. A deflector is an aerodynamic device that is installed above the chimney. It enhances the draft in the chimney by changing the air flow. The essence of its work lies in the pressure drop when air flows around an obstacle, as well as on the principle of changing air flows. It turns out that its shape allows you to increase the 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 varieties of smoke deflectors designed specifically for chimneys.

1. Volpert deflector.
2. Grigorovich deflector.
3. Round or spherical deflector.

In addition, weather vanes, umbrellas and similar structures are often installed on chimney pipes. But they can't do everything a high temperature chimney fan can do. Let's look at how they work and what makes them special.

smoke fan

The exhaust fan for the chimney is a heat-resistant electrical device. It is mounted directly on the chimney to increase the draft in the chimney. It is important not to confuse a chimney fan with a fireplace fan, which is needed to supply air to support combustion. Here the principle of operation is different. To put it simply, a chimney fan is an electric motor with blades that allow you to forcibly draw smoke out of the chimney and direct it to the street. For full operation of the fan, power supply from the 220V network is required.

In fact, a fan in the chimney to improve draft is somewhat reminiscent of a deflector, only wind force is not required for its operation. He works constantly, perfectly coping with his task. In addition, economical models can be found on sale. They operate in two modes: when there is a strong wind outside, the rotation occurs naturally, without the use of electricity. And in calm weather, an electric motor starts. it perfect solution for the chimney.

Scope of use of chimney fans

Such devices have found applications in many areas of life. Fans are an integral part heating system. It is important to understand that a fully 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 with your own hands, you will protect yourself and loved ones.

Here is where fans can be used:

• when arranging a fireplace;
• for the heating system;
• when creating a sauna or bath;
• for the forge.

Features of chimney structures

Since the smoke has high temperature and constantly affects the design, the chimney fan is made heat-resistant. The material is able to withstand temperatures up to 250 degrees. This is quite enough to serve faithfully for many years. Usually products are made of cast aluminum with a special coating. The motor has a lifetime bearing lubrication and is also heat resistant.

As for the types of fans, it all comes down to differences in their shape and power. After all, chimneys are different, respectively, you need to choose a device that would fit inside and have the shape of a chimney. These are the features of the choice of products for the chimney. Usually the design is made square or round shape.

Reviews of popular fans

MMOTORS JSC BO VO 90/25 T (+150°C)

Fine round shaped fan used for intermittent or long term operation. Its productivity is 60 m 3 / h, with a power of 16 watts. The product has an IP44 protection class. The landing 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 small length. Thanks to the low noise electric motor, which has double encapsulated ball bearings, the device will be able to work as much as 30,000 hours. The fan can be mounted both vertically and horizontally. The body is made of aluminum alloy, which cools quickly and can withstand temperatures up to 150 degrees. Warranty - 3 years. The cost is about $38.

MMOTORS JSC BA VA 9/2 T (+150)

Unlike the previous version, the fan has a square shape, and as for the parameters, they are practically the same. Power - all the same 16 W, performance, protection class, speed and other indicators are the same. But the landing diameter is 9.3x9.3, with a depth of 2.5 cm. Warranty - 3 years, cost - $ 38.5.

MMotors WOK 150/120 (+150°C)

The fan is also used for a round chimney. It is much more powerful than the previous options. With a power of 18 W, the device has a capacity of 240 m 3 / h. Landing 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. The cost is $90. Having bought such an exhaust fan for a chimney pipe, you can forget about weak draft.

Conclusion

The issue of increasing draft in the chimney is very important. Not only your comfort depends on this, but also your safety. Therefore, do 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.

Types and manufacture of chimney draft amplifiers

Reduced draft can lead to the return of combustion products into the room and poisoning carbon monoxide. To increase the traction force, special devices are used - amplifiers (stabilizers, fans, deflectors). You can buy them or make your own.

Reasons for reduced traction

Initially, it is necessary to examine the pipe for the fact of clogging with soot or other foreign objects (a clean chimney of the furnace, where the soot layer is not more than 2 mm). Then you should check the thrust with an anemometer and compare the indicator with the norm.

One of the factors affecting draft is incorrectly selected chimney metrics:

• too large or insufficient diameter of the chimney of the furnace;
• the length of the horizontal sections of the pipe or rotary elements;
• the length of the pipe for the furnace is incorrectly selected;
• chimney incorrectly located relative to the roof ridge.

The factors affecting the draft also include leaks in the chimney: lack of elements, fallen out bricks, cracks, gaps. They create additional circulation and air flow. Experts will tell you how to improve draft in the chimney, and you can also find a large amount of information on the methods and devices used on your own.

Ways to improve traction

• Deflector installation. One of the common devices for raising the aerodynamic performance of the chimney is a deflector. The essence of his work is to create the effect of low pressure (due to the rounded shape) at the time of flow around air flow, compensation occurs due to the withdrawal of combustible gases from the furnace tube.

To make a deflector with your own hands, you will need several sheets of stainless steel 1 mm thick, grinder, welding machine, clamp according to the diameter of the chimney, heat resistant sealant and other tools.

Diagrams and drawings of the deflector can be found on the Internet, drawn or printed on paper and transferred to a sheet of metal. After you need to cut out the elements, bend into the desired design and weld at the joints. Using a clamp, the structure is attached to the top of the chimney pipe.

• Installation of an automatic stabilizer. This chimney draft regulator maintains the optimum draft level through a damper or umbrella design when the pressure in the chimney increases. The stabilizer lowers it due to the additional air flow from the room. The stabilizer can be an element of a modular chimney system for stoves.

You can make an automatic stabilizer yourself, for this you will need stainless steel sheet 8-10 mm thick, steel bar, welding machine, grinder. Having prepared the stabilizer scheme in advance, cut out a piece of steel sheet and twist it into a pipe, then weld and grind the joint. After that, a hole is made for the limiter, equal to 15% of the diameter of the furnace chimney.

Two through holes are made in the pipe, into which a steel bar is placed, fixed on one side with screws, and on the other, 10 cm of its length are 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.

• smoke fan- very effective method create additional forced draft. The principle of operation of the fan lies in its location and rotation of the blades, which create a discharged airspace where the smoke goes.

Often a fireplace brick chimney is installed, it is also used for stoves. The fan requires an additional electrical connection, given fact for safety reasons is not always possible.

Use a fan as a draft booster, relevant for narrow stove chimneys, where aerodynamic natural indicators very weak, there is a need to increase these indicators. There are models of fans that, in addition to working from electricity when strong wind rotate due to mechanical rotation by the flow.

Previously, draft and draft fans were used only in industrial boiler plants. The first are placed inside the chimney channel and create a vacuum, the second - they pump air into the furnace. Gradually, the units migrated to the domestic sphere - manufacturers began to equip heaters with turbines with closed camera combustion. The idea was picked up by home craftsmen, because the exhauster for the boiler helps to solve the problem of poor draft in the chimney pipe. Let's see if forced exhaust of combustion products is always necessary.

Design and principle of operation

An exhaust smoke exhauster for a factory-made boiler includes the following elements (the device is shown in the diagram, the positions coincide with the points):

1. Metal heat-resistant impeller with blades bent at 90° relative to the impeller.
2. Mounting plate.
3. Electric motor of low productivity (20 ... 50 W).
4. Power cable connector.
5. Console with controls and controls.
6. The flask and capillary tube of the temperature sensor connected to the emergency thermostat.
7. Mains cable with plug.

Note. As an example, a DM-01 boiler smoke exhauster from Kalvis is taken. The design of other types of fans differs in the shape of the case - a snail, a duct, a hemispherical landing site. The set of parts is the same.

The unit is attached to a special box located on the rear panel of a household TT boiler next to the chimney pipe. The temperature sensor flask is inserted into the immersion sleeve of the water jacket, the control panel is placed separately.

The principle of operation of the smoke exhauster is the forced removal of high-temperature gases from the fire-tube heat exchanger of the boiler into the chimney. The algorithm looks like this:

1. The firebox is filled with firewood, ignition is carried out.
2. The loading door is locked, the blower door is opened. The fan is turned on with a key on the remote control, then the performance is adjusted.
3. When heating installation and the chimney warms up, the impeller speed is manually reduced to a minimum. If the heat generator has enough natural draft, it is recommended to turn off the smoke exhauster.
4. When the coolant is heated to a critical temperature of 100 °C or more, an emergency thermostat is triggered by the sensor, turning off the fan automatically.

Scheme of operation of the boiler smoke exhauster

Reference. On TT boilers equipped with an automatic one, the ash pan door does not need to be opened. The thermostat, by means of a chain, will open the air supply damper to the required angle.

High or low output of the draft fan is set individually depending on the quality solid fuel, combustion mode and the degree of heating of the chimney. The main thing is to avoid the accumulation and seepage of smoke into the room.

It is also impossible to overdo it with revolutions - the lion's share of the heat will go into the pipe. Before opening the door and reloading, it is better to increase the rotation speed to the maximum.

Ready-made fan unit of the famous Russian brand Zota is mounted on wood-burning heaters with a rear outlet of gases

Varieties of draft fans

For and wood-burning fireplaces, several types of smoke exhausters are sold:

• boiler room (design discussed above);
• centrifugal channel;
• overhead;
• fireplace / stove (aka roof).

It should not be attributed to smoke exhausters various nozzles that improve natural draft - deflectors, round rotary elements and rotating weather vanes. The effectiveness of these hoods depends on the wind speed, which changes with the weather.

Varieties of channel smoke exhausters, some models are equipped with temperature sensors

The duct fan is distinguished by its own housing with two connecting flanges or nozzles. The unit is installed vertically or horizontally in the gap of the chimney channel. The device and principle of operation is similar to the operation of a boiler smoke exhauster.

The overhead smoke exhauster for a domestic boiler is equipped with a semicircular platform and clamps-screeds. Installation is carried out on a vertical section of the chimney (non-insulated):

1. According to the paper template, an opening is cut out in the pipe.
2. The impeller of the traction machine is inserted into the hole, the platform with the electric motor is pressed against the surface with clamps.
3. The connection is sealed with asbestos cord glued to inside smoke exhauster mounting site.

Note. The overlay element is selected according to the diameter of the flue pipe. The installation process is shown in the video.

Electric hoods for pushing on the head brick chimney and fastened with expansion bolts. The power cable is laid through a pipe and introduced into the room next to the home stove.

To choose a traction machine, you need to focus on 3 criteria:

• heat generator power, smoke exhauster models are designed for boiler capacity up to 20, 30, 50 and 100 kW;
• installation point - on the boiler itself, pipe or head;
• for overhead models - the diameter of the non-insulated flue.

Overhead (left) and roof smoke exhauster (right)

When you need a smoker

Manufacturers of heating equipment complete their products with traction fans due to the increased resistance of the heat exchanger, where gases change the direction of movement through the flame tubes several times. The goal is to take maximum heat from the combustion products and increase the efficiency of the boiler plant.

Nuance: the operation of the smoke exhauster in the boiler of the factory configuration is coordinated with the combustion process and is controlled by an electronic unit. When installing a fan unit on a "brainless" heater, such consistency is excluded, you need to buy an automation unit or manually adjust the speed.

Organize supply ventilation in the boiler room, and only then think about installing a smoke exhauster

We list situations when a smoke exhauster will help improve the operation and maintenance of a solid fuel heat generator:

• traction problems - wind blowing, air locks in the gas duct, many turns, narrowing of the diameter;
• due to the design features, the boiler smokes into the room when the door is opened;
• the height of the chimney is insufficient or the cut of the pipe has fallen into the zone of wind support behind the ridge of the roof or another building;
• in brick pipe There are cracks where smoke seeps through.

An important point. Not a single fan will save the situation if there is no inflow from the street in the boiler room. At first, the working impeller will create a slight vacuum, but then the blades will begin to mix the air in place. - required condition normal operation any heater.

Mine heat generator V. G. Kholmov is better to operate with a traction fan

Some designs of wood-burning boilers (for example, shaft type) tend to emit smoke through an open loading hatch. A similar picture is observed in heat generators with a three-way fire-tube heat exchanger of increased resistance. The solution to the problem is the installation of a traction or blowing machine controlled by a controller.

Strengthening natural traction with a smoke exhauster has a downside. If after heating the pipe natural extract has not recovered, the unit cannot be turned off - you can get burned. Now imagine that in the middle of the night the power went out, the fan stopped. As long as the chain thermostat closes the damper, smoke will fill the boiler room.

What is better - a smoke exhauster or a supercharger?

When the traction turbine is integrated into the heat generator by the manufacturer, these issues do not arise. Another thing is adding an exhaust fan to a conventional direct combustion boiler. It must be understood that in this case, the smoke exhauster solves only 1 task - creating a vacuum in the furnace and increasing traction. There are a number of negatives here:

1. Without an electronic control unit, performance will have to be adjusted manually. Automatic maintenance of the coolant temperature is excluded.
2. When air is supplied through the open door of the ash chamber, the fan will force the boiler to work at maximum. It will not be easy to set up the long burn mode.
3. When emergency stop impellers, the combustion of fuel will not stop, since the gases pass freely through the volute or smoke exhauster housing. Air enters the furnace, the likelihood of overheating increases.
4. impeller and internal surfaces the unit is covered with soot, which must be removed. The sticking speed depends on the humidity and resin content of the wood.

Comment. We do not mention the power consumption of the fan. The consumption is relatively small and will not have a significant impact on total cost heating.

A blower fan with an automation unit performs the same functions as a smoke exhauster

The disadvantages described in paragraphs 1 and 2 are eliminated by switching the smoke exhauster with a controller that controls the speed of the impeller and the temperature of the water jacket. Electronic blocks can be bought at a price of 50-100 USD. e.

Blow machines always work in conjunction with the controller, so the above problems do not exist:

• the supercharger changes performance and turns off at the command of the control unit, the coolant is heated to the set temperature;
• during the combustion process, the ash pan door is hermetically closed, air is supplied through a separate channel;
• in the event of a power outage, the air channel is automatically closed by a gravity damper;
• impeller blades do not come into contact with hot smoke and soot.

Reference. AT pyrolysis boilers pressurization is always used, since the operation of this type of heater is based on forced air injection.

Now let's compare the cost of a draft fan and a blower fan, without taking into account the price of the controller. A smoke exhauster for a TT boiler up to 30 kW will cost 90 USD. e., supercharger - 60-65 c.u. e. The difference is due to the design features of the exhaust unit - hot gases should not overheat the electric motor, plus the impeller is made of metal (when pressurized, it is made of plastic).

Behind the mounting flange of the unit is a small impeller designed to cool the electric motor

In terms of installation complexity, the units are approximately the same. Installation of the injection snail involves cutting an opening in the ash pan door, a smoke exhauster - disassembling or cutting a pipe. It is easier to install a roof hood, but you will have to pull a long cable.

Brief conclusion: install a smoke exhauster only if necessary, or better, correct the mistakes made during the construction of the flue. Add an electronically controlled turbocharger at will - the system will automate and secure the combustion process.

How to make an exhaust unit

The main difficulty in assembling a smoke exhauster with your own hands is the manufacture of a balanced impeller, the rest of the details are not difficult for a home craftsman who knows how to weld. If the impeller blades vary in weight, normal fan noise will turn into rumble due to vibration.

In addition to the blades, you will need the following items:

• engine electric power up to 150 W, maximum shaft speed - 1400 rpm;
• snail or homemade box shown in the drawing;
• shaft with ventilation holes or an additional cooling impeller;
• studs with M8 nuts and other fasteners;
• power cable.

For ordinary homeowners, we offer the least thorny path - to buy a factory electric motor with an impeller and a cooling impeller, weld a box and assemble a fully functional channel smoke exhauster for a TT boiler. How to do it right, look at the video.

Conclusion

Creating an artificial vacuum using a smoke exhauster is rarely practiced in household solid fuel boilers. Technical solution leads to an increase in the cost of construction and creates problems in operation. Before putting the draft fan on the chimney, remember what kind of fuel you used earlier. If you plan to burn damp wood, agricultural waste or low-quality briquettes, forget about the exhaust fan for the boiler, you will have to clean the impeller weekly. It is better to install a supercharger with a control unit.