Do-it-yourself solid fuel boiler for wood. Do-it-yourself solid fuel boiler for heating a house

In modern times, few homeowners are ready to purchase heating equipment without thoroughly understanding what they are paying their hard-earned money for. This also applies to solid fuel boilers, whose range is quite wide. But it's enough for one person to know specifications equipment, while for others it is important to understand the operating principle of a particular heat generator. We present to your attention the currently existing diagrams of solid fuel boilers with a description of their operation. They may differ in detail for different products, but this will not affect the general principle.

Classic solid fuel boilers

This is the most common type heating installations burning solid fuels, they are also called direct combustion boilers. Due to their simplicity of design, these units are the cheapest of all and therefore are most often purchased by homeowners.

They are also popular among do-it-yourselfers, which is why it is not difficult to find drawings for the manufacture of traditional heat generators. The units can be divided into 2 types:

• non-volatile, operating on natural chimney draft;
• supercharged, with forced air injection.

The first operate on the principle of a conventional stove, only “clad” in a water jacket. The volumetric fuel chamber is located above the ash pan, separated from it by grates. Air from the room enters the firebox through the damper in the ash pan door and the grate. Its quantity is regulated by a chain-driven thermostat, which is guided by the temperature of the water in the boiler jacket and controls the air damper mechanically. For a better understanding of the process, a diagram of a solid fuel boiler is shown below:

Flue gases released in the firebox pass through the flame tubes of the heat exchanger, washed externally with water. Depending on the design of the heater, combustion products can make 2 or 3 passes through the flue ducts, intensively exchanging heat with the water jacket. Having given up their heat, the gases leave the unit through the chimney.

Note. In the above diagram of the heat generator, the flame tubes are located horizontally. There are models with vertical gas ducts, but this is not decisive.

Non-volatile solid fuel units cannot boast of high efficiency, a maximum of 70%. The duration of combustion depends on the volume of the firebox and the operating mode, although it is strongly recommended to use them in conjunction with a heat accumulator. The second type of boilers is more productive; their efficiency reaches 75% due to forced air supply by a fan. The design of such an installation is well reflected in the operation diagram of a solid fuel boiler presented below:

Long burning boilers

These units are no better in efficiency than traditional ones, their indicators are approximately the same: for atmospheric boilers - up to 70%, for forced-air boilers - up to 75%. But the duration of combustion from one load of firewood or coal is actually increased. This is achieved thanks to the following technical solutions:

• increased dimensions of the fuel chamber, which can accommodate twice as much firewood as in a conventional boiler;
• The combustion method is unconventional - from top to bottom.

Such heat generators have cylindrical shape, since it is hardly possible to implement the idea in a rectangular case. The firebox is filled to the top with wood, ignited from above, and then a load with a hole for air passage is lowered onto it using a telescopic pipe. As it burns, the load is lowered, which is why air is constantly supplied directly to the flame zone. The illustration below shows a diagram of a solid fuel boiler long burning:

The air also passes through the telescopic pipe from top to bottom, driven by the natural draft of the chimney or forced by a fan. The design does not provide for a heat exchanger; the process of heating the coolant occurs directly, although the flue gases also manage to give up some of their heat. Thanks to the described combustion method, the boiler and heating system can operate with one load of wood for up to 12 hours, and coal for up to 2 days.

Pyrolysis boilers

The operating principle of these heat generators is based on separate combustion in two chambers communicating with each other through a nozzle made of refractory bricks. In the primary chamber, located on top, firewood smolders with limited air supply from the fan. As a result, a process of pyrolysis occurs, otherwise known as gasification, during which a mixture of flammable gases is released. It moves to the second chamber, where it is burned when secondary air enters. The working diagram of a pyrolysis boiler operating on solid fuel is as follows:

Flue gases from the secondary furnace enter the fire tube heat exchanger in the form of vertical flues surrounded by a water jacket. There they cool, transferring heat to the water, and leave the boiler through the chimney pipe. The performance of the fan is controlled by an electronic unit - controller, based on the readings of pressure and temperature sensors.

In general, the heat generator has good efficiency indicators - about 80%, but the unit is significantly more expensive than a classic one. In addition, the boiler shows high efficiency only when operating on dry wood, although this statement is also true for other solid fuel units.

Pellet boilers

This group of heat generators is the most progressive of all, although the most expensive. Both the heater itself and its installation and connection will be expensive. But pellet boilers are worth the money: they are efficient (efficiency - up to 85%), fully automated and devoid of the inertia inherent in other solid fuel “brothers”. Since the fuel reserve in the bunker is enough for 3-7 days of operation, they can be safely classified as long-burning units.

Structurally, the installations are similar to gas heaters, since they are equipped with two types of burners: retort and torch. The figure shows a drawing of a long-burning solid fuel boiler using pellets with different types of burners:

The organization of heat transfer here is the same as in other heat generators - using fire tube heat exchangers. High efficiency is achieved due to something else: dry, high-quality fuel and automatically controlled combustion. But if you come across wet or loose pellets, then the efficiency of the unit will sharply decrease.

For reference. Automatic coal boilers operate on the same principle, only the burners in them are of one type - retort.

A little about DHW circuits

Due to their characteristics, any solid fuel heaters are poorly suited for direct heating of water for domestic hot water needs. Nevertheless, some manufacturers still integrate a second circuit in the form of a coil into their products. At the same time, the design of double-circuit solid fuel boilers can be different; the coil can be located inside the water jacket and heated by the coolant. In other models it is placed inside the firebox or above it.

The best option is not to place a heat exchanger inside a wood-burning heat generator, but to prepare water in an indirectly heated boiler, which will also serve as a heat accumulator. But not everyone can afford to purchase such equipment, so users are still interested in dual-circuit units, although they are unlikely to be able to provide all the needs for hot water. Below is a diagram of installing a boiler with a function of heating water for domestic hot water:

Conclusion

As you can see, the device and principle of operation thermal equipment on solid fuel can vary greatly. It should be noted that for convenience, the diagrams of various boilers are presented in order of increasing cost of design. All you have to do is process this information and make the right choice for yourself.

Most solid-state boilers have one significant drawback - the fuel in them burns out very quickly and you need to make sure you have time to put in the next portion. However, this entails irrational use of firewood, briquettes, pellets and, as a consequence, high heating costs.

The solution to this problem can be a purchased or homemade long-burning boiler with wood, which will maintain their long-term smoldering and high temperature. Certain factory models can even work without firing pads for up to 20-25 hours. In addition, they can be heated with other types of solid fuel, including waste that can be burned.

Operating principle of a long-burning boiler

The basic principle of operation of long-lasting boilers is based not on the combustion of fuel, but on its smoldering inside the combustion chamber. At this moment, the wood fires emit more heat. It is impossible to achieve such a result in classic brick kilns, since they cannot create active draft.

The design features of the long-burning furnace make it possible to achieve maximum efficiency of heat release during the long, slow smoldering of wood. In homemade installations, one bookmark can last more than 6-8 hours.

The boiler is equipped with a special valve -. After the logs begin to burn profusely, it is necessary to shut it off and minimize the flow of oxygen with air inside. Gradually smoldering, firewood releases the so-called “flue gas”, consisting of methane, carbon monoxide and hydrogen.

The main source of heat is the “flue gas”. When it gets into the ignition chamber, it ignites, burns very quickly and releases a large amount of energy.

See also instructions on how to do it yourself

How does everything work?

It is recommended to make a long-burning boiler using wood from steel pipes or a barrel with a diameter of about 30-40 cm. In this case, the wall thickness should not be less than 3-5 mm, otherwise the metal will quickly burn out and the installation will become unusable. It can reach a height of 0.8-1 m - the higher, the more firewood can be laid. However, you shouldn't exaggerate too much.

Click on the picture to enlarge

The installation is divided into three conventional parts:

1. Combustion zone - where smoke is removed and the room smolders
2. Combustion zone - directly in it the fuel slowly smolders
3. Loading area – it gradually decreases in height, as firewood and briquettes burn out

The air distributor is one of the main devices of the furnace, as it directly affects the duration of smoldering, limiting the area in which combustion occurs. It is a round disk made of sheet steel more than 4 mm thick, in which there is a pipe in the middle - through it air enters the inside of the firebox. In order for the distributor to lower freely as the fuel smolders, its size is made slightly smaller than the combustion chamber.

To control the size of the combustion zone through which air circulates, the distributor has an impeller up to 5 cm high. If you make it larger, the free space inside will increase and the firewood will burn out very quickly.

The diameter of the pipe for air intake is made equal to 5-6 cm. It can be solid or telescopic. In this case, the hole in the distributor should not exceed 2 cm, otherwise oxygen oversaturation will occur. There will be a damper at the top, which will allow you to regulate the draft.

A homemade long-burning wood-burning boiler can also be connected to heating in a private home. This can be done using one of two methods:

• A water heat exchanger pipe is passed through the combustion chamber; in the tank, the water will be heated by a coil connected directly to this pipe
• The smoke pipe is passed through a remote tank. Hot smoke will pass through it and heat up the coolant.

If we compare both methods, it should be noted: the first is much simpler, but the second is several times more effective.

Video - making a wood-burning boiler with your own hands

Manufacturing instructions

When starting the production process, you need to start by preparing all the essentials:

• Pipes with the following diameters - 30 cm, 5-6 cm, 10 cm (the wall thickness of each is at least 3 mm)
• Steel sheet with a thickness of more than 4 mm
• Bulgarian
• Welding machine
• Hand tools

Let's start making the boiler:

A good alternative to firewood is - see our review

Chimney and reflector

The walls of the boiler will constantly heat up and radiate thermal energy. If the installation is installed to heat a small room, reflectors should be placed around it - they will distribute the flow, increasing the heat flow inside.

If it will be located in a room with constant presence of people, you should think about their safety. One solution to the problem is to cover the structure with brickwork.

The chimney can be made from a 20 mm pipe. The horizontal straight section should be 5-10 cm larger than the diameter of the combustion chamber. It is necessary to take it outside with a minimum number of bends - 2 x 45 degrees.

A few other features:

• It is recommended to make the chimney dismountable so that it can be easily cleaned of soot 2-3 times a season
• The chimney sections must be connected in the direction opposite to the gas movement
• All structures and objects that are easily flammable must be kept at a safe distance

We are building the foundation

It can be assumed that a long-burning wood-burning stove will constantly heat up to high temperatures. A simple leveled floor is not the best solution for it - a foundation should be built.

The base can be made of burnt brick or rubble. They do not heat up when exposed to elevated temperatures. All those who want to make a more solid foundation can pour a solid monolithic slab.

The boiler can also be installed on legs, which can be easily welded from channel wood. They hide from view behind brickwork.

Using the boiler

Unlike a classic stove, air must enter a long-burning wood-burning boiler in a certain amount. To achieve this, the filling must be done in full, trying not to leave free cavities. It is recommended to add sawdust, pellets, peat or combustible waste to the logs.

Fuel must be added according to the following instructions:

1. Remove the cap and remove the regulator from the tank
2. Pack the fuel tightly
3. Spray flammable liquid on top
4. Install the regulator, cover with the lid and open the damper
5. Throw a splinter into the air pipe and when it starts to smolder, close the damper

Let's sum it up

A simple long-burning wood-burning boiler is ready. You can install such a structure in any unheated room: from a small garage to a workshop. If everything was done correctly, there will be no doubt about the efficiency and high efficiency.

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“A boiler is really a stove in a barrel of water”... and the efficiency of such a unit will be best case scenario 10%, or even 3-5%. After all, a solid fuel boiler is not a stove at all, and a solid fuel stove is not a hot water boiler. The fact is that the combustion process of solid fuel, unlike gas or flammable liquids, is certainly extended in space and time. Gas or oil can be completely burned immediately in a small gap from the nozzle to the burner diffuser, but wood and coal cannot. Therefore, the requirements for the design of a solid fuel heating boiler are different than for a heating furnace; it is impossible to simply put a heating circuit water heater into it in continuous circulation. Why this is so, and how a continuous heating boiler should be designed, is what this article is intended to explain.

Your own heating boiler in a private house or apartment becomes a necessity. Gas and liquid fuels are steadily becoming more expensive, and in return, inexpensive alternative fuels are appearing on sale, for example. from crop waste - straw, husks, husks. This is only from the point of view of the owners of the house, not to mention the fact that the transition to individual heating will allow you to get rid of energy losses in the main lines of thermal power plants and power line wires, and they are by no means small, up to 30%

You cannot make a gas boiler yourself, if only because no one will give permission to operate it. It is prohibited to use individual liquid fuel boilers for heating residential premises due to their high fire and explosion hazard when used in a decentralized manner. But you can make a solid fuel boiler with your own hands and register it officially, just like a heating stove.

This is perhaps the only thing they fundamentally have in common.

Features of solid fuel Solid fuel does not burn very quickly, and not all components carrying thermal energy burn in its visible flame. For complete burning flue gases

a high, but well-defined temperature is required, otherwise conditions will arise for endothermic reactions to occur (for example, nitrogen oxidation), the products of which will carry away the energy of the fuel into the pipe.

The oven is a cyclic device. So much fuel is loaded into its firebox at once so that its energy lasts until the next fire. The excess combustion energy of the fuel load is partially used to maintain the optimal temperature for afterburning in the gas path of the furnace (its convective system), and is partially absorbed by the furnace body. As the load burns out, the ratio of these parts of fuel energy changes, and a powerful flow of heat circulates inside the furnace, several times more powerful than the current needs for heating.

The body of the stove is thus a heat accumulator: the main heating of the room occurs due to its cooling after heating. Therefore, it is impossible to take away the heat circulating in the furnace; this will somehow disrupt its internal thermal balance, and the efficiency will drop sharply. It is possible, and even then not in every place of the convection system, to take up to 5% to replenish the hot water storage tank. Also, the stove does not require operational adjustment of its thermal power; it is enough to load fuel based on the required average hourly time between firings.

A water boiler, no matter what fuel it uses, is a continuous operation device. The coolant circulates in the system all the time, otherwise it will not heat, and the boiler must at any given moment provide exactly as much heat as was lost outside due to heat loss. That is, fuel must either be periodically loaded into the boiler, or the thermal power must be quickly adjusted within a fairly wide range.

The second point is flue gases. They must approach the heat exchanger, firstly, as hot as possible in order to ensure high efficiency. Secondly, they must be completely burned out, otherwise the fuel energy will be deposited on the register as soot, which will also need to be cleaned.

Finally, if the stove heats around itself, then the boiler as a heat source and its consumers are separated. The boiler requires a separate room (boiler room or furnace): due to the high concentration of heat in the boiler it fire danger much higher than the ovens.

Note: An individual boiler room in a residential building must have a volume of at least 8 cubic meters. m, ceiling at least 2.2 m high, opening window at least 0.7 sq. m, a constant (without valves) flow of fresh air, a smoke channel separate from other communications and a fire separation from the other rooms.

From this it follows, firstly, boiler furnace requirements:

• It should ensure rapid and complete combustion of fuel without a complex convection system. This can only be achieved in a firebox made of materials with the lowest possible thermal conductivity, because For rapid combustion of gases, a high concentration of heat is required.
• The firebox itself and the parts of the structure associated with it in heat should have the lowest possible heat capacity: all the heat that went into heating them will remain in the boiler room.

These requirements are initially contradictory: materials that conduct heat poorly, as a rule, accumulate it well. Therefore, a regular stove firebox will not work for a boiler; some kind of special one is needed.

Heat exchange register

The heat exchanger is the most important component of a heating boiler; it mainly determines its efficiency. Based on the design of the heat exchanger, the entire boiler is called. In household heating boilers, heat exchangers are used - water jackets and tubular, horizontal or vertical.

A boiler with a water jacket is the same “stove in a barrel”; a heat exchange register in the form of a tank surrounds the firebox. A jacketed boiler can be quite economical under one condition: if the combustion in the firebox is flameless. A flaming solid fuel furnace certainly requires afterburning of the exhaust gases, and in contact with the jacket their temperature immediately drops below the value required for this. The result is an efficiency of up to 15% and increased deposition of soot and even acid condensate.

Horizontal registers, generally speaking, are always inclined: their hot end (supply) must be raised above the cold end (return), otherwise the coolant will flow backwards, and failure of forced circulation will immediately lead to a serious accident. In vertical registers, the pipes are located vertically or slightly inclined to the side. In both cases, the pipes are arranged in rows in a checkerboard pattern, so that gases are better “entangled” in them.

Regarding the directions of movement of hot gases and coolant, pipe registers are divided into:

1. Flow-through – gases generally flow perpendicular to the coolant flow. Most often, this scheme is used in horizontal industrial boilers. high power for the sake of their smaller height, which reduces the cost of installation. In households, the situation is the opposite: in order for the register to properly capture the heat, it has to be extended upward above the ceiling.
2. Countercurrent - gases and coolant move along the same line towards each other. This scheme provides the most efficient heat transfer and the highest efficiency.
3. Flow - gases and coolant move parallel in one direction. Rarely used in boilers special purpose, because At the same time, efficiency is poor, and equipment wear is high.

Further, heat exchangers are made of fire tube and water tube. In fire tubes, smoke tubes carrying flue gases pass through a tank of water. Fire tube registers operate stably, and vertical ones provide good efficiency even in a flow diagram, because internal water circulation is established in the tank.

However, if we calculate the optimal temperature gradient for heat transfer from gas to water based on the ratio of their density and heat capacity, then it turns out to be approximately 250 degrees. And in order to push this heat flow through the wall of a steel pipe of 4 mm (you can’t do less, it will burn out very quickly) without noticeable losses on the thermal conductivity of the metal, you need about another 200 degrees. As a result, the inner surface of the smoke pipe should be heated to 500-600 degrees; 50-150 degrees – operational margin for fuel water cut, etc.

Because of this, the service life of the smoke tubes is limited, especially in large boilers. In addition, the efficiency of a fire tube boiler is low; it is determined by the ratio of the temperatures of hot gases entering the register and those exiting the chimney. It is impossible to allow gases to cool below 450-500 degrees in a fire tube boiler, and the temperature in a conventional firebox does not exceed 1100-1200 degrees. According to the Carnot formula, it turns out that the efficiency cannot be higher than 63%, and the efficiency of the firebox is no more than 80%, so the total is 50%, which is very bad.

In small domestic boilers these features have a weaker effect, because when the size of the boiler decreases, the ratio of the register surface to the volume of flue gases in it increases, this is the so-called. square-cube law. In modern pyrolysis boilers, the temperature in the combustion chamber reaches 1600 degrees, the efficiency of their furnace is 100%, and the registers of branded boilers, guaranteed for 5 years or more, are made only of thin-walled heat-resistant special steel. In them, gases can be allowed to cool to 180-250 degrees, and the overall efficiency reaches 85-86%

Note: Cast iron is generally unsuitable for smoke pipes; it cracks.

In water-tube registers, the coolant flows through pipes placed in a fire chamber into which hot gases enter. Now temperature gradients and the square-cube law operate in the opposite way: at 1000 degrees in the chamber, the outer surface of the pipes will be heated to only 400 degrees, and the inner surface to the temperature of the coolant. As a result, pipes made of ordinary steel last a long time and the boiler efficiency is about 80%

But horizontal flow-through water tube boilers are prone to the so-called. "flooding". The water in the lower pipes turns out to be much hotter than in the upper ones. It is pushed into the supply first, the pressure drops, and the colder upper pipes “spit out” the water. “Buhtenie” not only provides as much noise, heat and comfort as a neighbor who is a drunkard and a brawler, but is also fraught with a break in the system due to water hammer.

Vertical water-tube boilers do not fire, but if a water-tube boiler is being designed for a house, the register should be located at the bottom of the chimney, in the section where hot gases flow from top to bottom. In an in-line water-tube boiler with the same direction of movement of gases and coolant, the efficiency drops sharply and soot is intensively deposited on the pipes near the supply, and it is generally unacceptable to make a return above the supply.

About the heat exchanger capacity

The ratio of the heat exchanger capacities and the entire cooling system is not taken arbitrarily. The rate of heat transfer from gases to water is not infinite; the water in the register must have time to absorb heat before it leaves the system. On the other hand, the heated outer surface of the register gives off heat to the air, and it is wasted in the boiler room.

A register that is too small is prone to boiling and requires precise, quick adjustment of the firebox power, which is unattainable in solid fuel boilers. A large-volume register takes a long time to warm up and, if the external thermal insulation of the boiler is poor or absent, it loses a lot of heat, and the air in the boiler room can warm up above the permissible temperature. fire safety and technical specifications for the boiler.

The size of the heat exchanger capacity of solid fuel boilers ranges from 5-25% of the system capacity. This must be taken into account when choosing a boiler. For example, for heating, according to the calculation, there were only 30 sections of radiators (batteries) of 15 liters each. With water in the pipes and an expansion tank, the total capacity of the system will be about 470 liters. The boiler register capacity should be between 23.5-117.5 liters.

Note: There is a rule - the greater the calorific value of solid fuel, the greater the relative capacity of the boiler register should be. Therefore, if the boiler is coal-fired, the register capacity should be taken closer to the upper value, and for a wood-burning boiler - to the lower value. For slow-burning boilers, this rule is not valid; the capacity of their registers is calculated based on the highest efficiency of the boiler.

What is the heat exchanger made of?

Cast iron as a material for a boiler register does not meet modern requirements:

• The low thermal conductivity of cast iron leads to low boiler efficiency, because It is impossible to cool the exhaust gases below 450-500 degrees; as much heat as needed will not pass through the cast iron into the water.
• The high heat capacity of cast iron is also its disadvantage: the boiler must quickly release heat into the system before it evaporates somewhere else.
• Cast iron heat exchangers do not fit into modern requirements by weight and dimensions.

For example, let's take the M-140 section from the old Soviet cast iron battery. Its surface area is 0.254 square meters. m. For heating 80 sq. m of living space, a heat exchange surface in the boiler of approximately 3 square meters is required. m, i.e. 12 sections. Have you seen a battery with 12 sections? Imagine what the cauldron must be like in which it will fit. And the load on the floor from it will definitely exceed the limit according to SNiP, and a separate foundation will have to be made for the boiler. In general, 1-2 cast iron sections will go to the heat exchanger feeding storage tank DHW, but for a heating boiler the question of a cast iron register can be considered closed.

The registers of modern factory boilers are made of heat-resistant and heat-resistant special steel, but their production requires production conditions. What remains is ordinary structural steel, but it corrodes very quickly at 400 degrees and above, so fire tube boilers made of steel must be selected for purchase or developed very carefully.

In addition, steel conducts heat well. On the one hand, this is not bad, you can count on by simple means get good efficiency. On the other hand, the return flow should not be allowed to cool below 65 degrees, otherwise acidic condensate will fall onto the register in the boiler from the flue gases, which can eat through the pipes within an hour. You can exclude the possibility of its deposition in 2 ways:

• For boiler power up to 12 kW, a bypass valve between the boiler flow and return is sufficient.
• At more power and/or a heated area of ​​more than 160 sq. We also need an elevator unit, and the boiler must operate in the mode of superheating water under pressure.

The bypass valve is controlled either electrically from a temperature sensor, or energy-independently: from a bimetallic plate with traction, from wax melting in a special container, etc. As soon as the temperature in the return drops below 70-75 degrees, it admits hot water from the supply into it.

The elevator unit, or simply the elevator (see figure), acts in the opposite way: the water in the boiler is heated to 110-120 degrees under pressure of up to 6 ati, which eliminates boiling. To do this, the combustion temperature of the fuel is increased, which increases efficiency and eliminates condensation. And before entering the system, hot water is diluted with return water.

In both cases, forced water circulation is necessary. However, a steel thermosiphon circulation boiler that does not require power supply for circulation pump, it is quite possible to create. Some designs will be discussed below.

Circulation and boiler

Thermosiphon (gravity) circulation of water does not allow heating a room with an area of ​​more than 50-60 square meters. m. The point is not only that it is difficult for water to squeeze through a developed system of pipes and radiators: if you open the expansion tank when the expansion tank is full drain valve, the water will gush out in a strong stream. The fact is that the energy for pushing water through the pipes is taken from the fuel, and the efficiency of converting heat into movement in a thermosiphon system is negligible. Therefore, the efficiency of the boiler as a whole decreases.

But the circulation pump requires electricity (50-200 W), which may be lost. UPS (source uninterruptible power supply) for 12-24 hours battery life is very expensive, so a properly designed boiler is designed for forced circulation, and if the power supply is lost, it must, without outside intervention, switch to thermosiphon mode, when the heating is barely warm, but still warms.

How to install the boiler?

The requirement for a boiler’s minimum intrinsic heat capacity directly follows from its low weight compared to a stove and its weight load per unit floor area. As a rule, it does not exceed the minimum allowable according to SNiP for flooring of 250 kg/sq. m. Therefore, installing a boiler is permissible without a foundation and even dismantling the flooring, incl. and on the upper floors.

Place the boiler on a flat, stable surface. If the floor plays, it will still have to be disassembled at the place where the boiler is installed. concrete screed with a side offset of at least 150 mm. The base for the boiler is covered with asbestos or basalt cardboard 4-6 mm thick, and a sheet is placed on it roofing iron 1.5-2 mm thick. Next, if the flooring has been dismantled, the bottom of the boiler is lined cement-sand mortar to floor level.

Around the boiler protruding above the floor, thermal insulation is made, the same as underneath: asbestos or basalt cardboard, and iron on it. The removal of insulation to the sides from the boiler is from 150 mm, and in front of the firebox door is at least 300 mm. If the boiler allows additional fuel loading before the previous portion burns out, then the removal in front of the firebox is required from 600 mm. Under the boiler, which is placed directly on the floor, place only thermal insulation, covered steel sheet. Removal - as in the previous case.

A separate boiler room is required for a solid fuel boiler. The requirements for it are given above. Moreover, almost everything solid fuel boilers do not allow power adjustment over a wide range, so they require a full-fledged harness - a kit additional equipment, ensuring efficient and trouble-free operation. We’ll talk about it later, but in general, boiler piping is a separate big topic. Here we mention only the immutable rules:

1. Installation of the piping is carried out in counterflow to the water, from the return to the supply.
2. Upon completion of installation, its correctness and quality of connections are checked visually according to the diagram.
3. The installation of the heating system in the house begins only after piping the boiler.
4. Before loading fuel and, if required, supplying power, the entire system is filled with cold water and all joints are monitored for leaks during the day. IN in this case water is water, and not some other coolant.
5. If there are no leaks, or after they have been eliminated, the boiler is started on water, continuously monitoring the temperature and pressure in the system.
6. Once the nominal temperature is reached, the pressure is controlled for 15 minutes; it should not change by more than 0.2 bar, this process is called pressure testing.
7. After pressure testing, the boiler is extinguished and the system is allowed to cool completely.
8. Drain the water and fill in the standard coolant.
9. Check the joints for leaks once again 24 hours. If everything is in order, the boiler is started. No - they fix the leaks, and again daily monitoring before starting.

Choosing a boiler

Now we know enough to choose a boiler based on the intended type of fuel and its purpose. Let's get started.

Wood burning

The calorific value of firewood is low, the best ones have less than 5000 kcal/kg. Firewood burns quite quickly, releasing a large volume of volatile components that require afterburning. Therefore, it is better not to count on high efficiency using wood, but they can be found almost everywhere.

Wood burning for the house

A home wood-burning boiler can only burn for a long time, otherwise it will damage it in all respects. Industrial structures, e.g. the well-known KVR, cost from 50,000 rubles, which is still cheaper than building a furnace, do not require power supply and allow power adjustment for heating in the off-season. As a rule, they operate on coal and any solid fuel, except sawdust, but with coal, fuel consumption will be much higher: heat transfer from one load is 60-72 hours, and for specialized coal ones – up to 20 days.

However, a long-burning wood-burning boiler can be useful in places where there is no regular supply of coal and qualified heating service. It costs one and a half times less than coal, its jacket design is very reliable and allows you to build a thermosiphon heating system with an area of ​​up to 100 square meters. m.. In combination with smoldering fuel thin layer and with a fairly large volume of the jacket, boiling of water is excluded, so the piping is sufficiently the same as for titanium. Connecting a long-burning wood-burning boiler is also no more difficult than titanium, and can be done independently by an unqualified owner.

About brick boilers

Diagram of the boiler “Blago”

Brick is the friend of the stove and the enemy of the boiler due to the fact that it gives the structure greater thermal inertia and weight. Perhaps the only brick boiler in which the brick is in its place is Belyaev’s pyrolysis “Blago”, diagram in Fig. And then, its role here is completely different: the lining of the combustion chamber is made of fireclay bricks. Horizontal water tube heat exchanger; The problem of coiling is solved by the fact that the register pipes are single, flat, elongated in height.

Belyaev’s boiler is truly omnivorous, and there are 2 separate bunkers for loading different types fuel without stopping the boiler. “Blago” can work on anthracite for several days, on sawdust – up to a day.

Unfortunately, Belyaev’s boiler is quite expensive, due to the fireclay lining it is poorly transportable and, like all pyrolysis boilers, requires complex and expensive piping. Its power is regulated within small limits by bypassing flue gases, so it will show good efficiency on average for the season only in places with prolonged severe frosts.

About boilers in the furnace

The boiler in the furnace, which is now talked and written about so much - a water-tube heat exchanger walled up in stove masonry, see fig. below. The idea is this: after firing, the stove should give off more heat than before. ambient air. Let's say right away: reports of an efficiency of 80-90% are not only doubtful, but simply fantastic. The best brick oven itself has an efficiency of no more than 75%, and its area outer surface will be at least 10-12 sq. m. The surface area of ​​the register is unlikely to be more than 5 square meters. m. In total, less than half of the heat accumulated by the furnace will go into the water, and the overall efficiency will be below 40%

Next point - a stove with a register immediately loses its properties. Under no circumstances should you heat it out of season with an empty register. TKR ( temperature coefficient expansion) of metal is much greater than that of a brick, and the heat exchanger, swollen from overheating, will tear the stove before our eyes. Thermal seams will not help the matter; the register is not a sheet or a beam, but a three-dimensional structure, and it is bursting in all directions at once.

There are other nuances here, but the general conclusion is clear: a stove is a stove, and a boiler is a boiler. And the fruit of their forced unnatural union will not be viable.

Boiler piping

Boilers that prevent boiling of water (long-burning jacket boilers, titanium boilers) cannot be made with a power of more than 15-20 kW and cannot be extended in height. Therefore, they always provide heating for their area in thermosiphon mode, although a circulation pump, of course, would not hurt. In addition to the expansion tank, their piping includes only an air drain valve at the highest point of the supply pipeline and a drain valve at lowest point return lines

The wiring of solid fuel boilers of other types should provide a set of functions, which can be better understood in Fig. on right:

1. safety group: air drain valve, general pressure gauge and breakthrough valve for releasing steam during boiling;
2. emergency cooling storage tank;
3. its float valve is the same as in the toilet;
4. thermal valve for starting emergency cooling with its sensor;
5. MAG block - drain valve, emergency drain valve and pressure gauge, assembled in one housing and connected to a membrane expansion tank;
6. forced circulation unit with a check valve, a circulation pump and an electrically temperature-controlled three-way bypass valve;
7. intercooler - emergency cooling radiator.

Pos. 2-4 and 7 make up the power reset group. As already mentioned, solid fuel boilers are regulated in terms of power within small limits, and with sudden warming, the entire system may overheat unacceptably, even to the point of bursting. Then thermal valve 4 starts tap water into the intercooler, and it cools the supply to normal.

Note: The owner's money for fuel and water flows quietly and peacefully down the drain. Therefore, solid fuel boilers for areas with mild winter and the long off-season are unsuitable.

The forced circulation group in normal mode bypasses part of the supply to the return line so that its temperature does not fall below 65 degrees, see above. When the power supply is turned off, the thermal valve closes. The heating radiators receive as much water as they can handle in thermosiphon mode, just so that the rooms can be lived in. But the intercooler thermal valve opens completely (it is kept closed under voltage), and excess heat again carries the owner’s money down the drain.

Note: If the water goes out along with the electricity, the boiler needs to be extinguished immediately. When water flows out of tank 2, the system will boil.

Boilers with built-in overheating protection are 10-12% more expensive than conventional ones, but this is more than compensated by simplifying the piping and increasing the reliability of the boiler: here excess superheated water is poured into an open large-capacity expansion tank, see figure, from where it cools and flows into return. The system, except for circulation pump 7, is energy-independent and switches to thermosiphon mode smoothly, but with sudden warming, the fuel is still wasted, and the expansion tank must be installed in the attic.

As for pyrolysis boilers, then standard diagram Their bindings are provided for informational purposes only. All the same, its professional installation will cost only a fraction of the cost of the components. For reference: the heat accumulator alone for a 20 kW boiler costs about $5,000.

Note: membrane expansion tanks Unlike open ones, they are installed on the return line at its lowest point.

Chimneys for boilers

Chimneys of solid fuel boilers are calculated in general in the same way as stoves. General principle: a chimney that is too narrow will not provide the required draft. This is especially dangerous for the boiler, because it is heated continuously and fumes can occur at night. A chimney that is too wide leads to “whistle”: cold air descends through it into the firebox, cooling the stove or register.

The boiler chimney must meet the following requirements: the distance from the ridge of the roof and between different chimneys is at least 1.5 mm, the lift above the ridge is also at least 1.5 m. Safe access to the chimney must be provided on the roof at any time of the year. There must be a cleanout door at every chimney break outside the boiler room, and every pipe passage through the ceilings must be thermally insulated. The upper end of the pipe must be equipped with an aerodynamic cap; for a boiler chimney, it is required, unlike for a stove. Also, a condensate collector is required for the boiler chimney.

In general, calculating a chimney for a boiler is somewhat simpler than for a stove, because The boiler chimney is not so tortuous; the heat exchanger is considered simply a lattice barrier. Therefore, it is possible to build generalized graphs for different design cases, for example. for a chimney with a horizontal section (burrow) of 2 m and a condensate collector 1.5 m deep, see fig.

Using such graphs, after accurate calculations using local data, you can estimate whether there was a gross error. If the calculated point is somewhere around its generalized curve, the calculation is correct. In extreme cases, you will have to extend or cut the pipe by 0.3-0.5 m.

Note: if, say, for a pipe 12 m high there is no curve for a power less than 9 kW, this does not mean that a 9 kW boiler cannot be operated with a shorter pipe. It’s just that for lower pipes a generalized calculation is no longer possible, and it is necessary to calculate exactly according to local data.

Video: example of construction of a shaft-type solid fuel boiler

conclusions

The depletion of energy resources and rising fuel prices have radically changed the approach to the design of household heating boilers. Now they, like industrial ones, are required to have high efficiency, low thermal inertia and the ability to quickly regulate power over a wide range.

In our time heating boilers According to the basic principles embedded in them, they finally parted ways with the stoves and were divided into groups for different climatic conditions. In particular, the considered Solid fuel boilers are suitable for areas with harsh climates and prolonged severe frosts. For places with a different climate, heating devices of other types will be preferable.

Residents of the private sector who decide to purchase a solid fuel boiler to heat their home are primarily interested in the thermal power of the equipment, the price and duration of combustion per load. These parameters are interrelated: with greater power and operating time, the price of the device is higher. There is an option in which costs are halved - homemade long-burning wood-burning boilers.

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  Characteristics and types of boilers

  In suburban villages (where there are no gas pipelines), the issue of improving the quality of home heating is constantly being addressed. Conventional coal and wood stoves have become widespread, and now, with new technologies, they are not the only heating method.

  It is perfectly possible to replace old stoves with long-burning wood-burning boilers, which are relatively new designs that run on solid fuel. The power of such a device is enough to heat not only residential but also industrial premises.

  The duration of combustion corresponds to the processes occurring inside it, which will depend on the design of the device. A solid fuel boiler differs in operating technology from a conventional wood-burning stove in that the upper part of the wood burns first, gradually capturing the lower part along with decay products (ash, soot).

  In old stoves, the firewood ignites from below, and then the rest ignites, while the fuel burns quickly and the stove cools down, so you have to watch the combustion process and often add firewood. It is usually believed that the duration of combustion depends on the duration of smoldering with limited air supply. But this is an inefficient way to burn wood and coal.:

  1. 1. At maximum combustion, the efficiency of wood-burning boilers reaches 75%, and in smoldering mode, the efficiency of the device drops to 40%.
  2. 2. Smoldering firewood releases a small amount of thermal energy, which affects the complete, high-quality heating of the house.
  3. 3. The impossibility of burning freshly cut wood such as willow, poplar and low-calorie fuel by smoldering.

  The duration of combustion depends on the enlarged fuel chamber in the boiler; it is its size that influences the process: the more firewood put into the firebox, the longer it will burn and generate heat. Household units can operate for 10-12 hours with one load of firewood, and with a portion of coal for up to a day. There are such types of solid fuel boilers:

  • classic ones that function forced submission air;
  • operating using the top combustion method;
  • pyrolysis models;
  • mine type heat generators.

  Such devices for solid fuel boilers can be made independently. To do this you need to have necessary tool and welding practice.

  WHICH boiler is BETTER: we consider all options #2

  

  Classic type of unit

  This type is used using forced pressurization, which is necessary to avoid smoldering conditions and for economical combustion of solid fuel.

  
  
  

  The principle of operation is this:

  1. 1. Firewood is placed and set on fire in a firebox with a volume of 112 liters. After this, all the doors are closed tightly, and with the help of automation, the fan is started, pumping air.
  2. 2. As soon as the temperature reaches the set point, it stops in standby mode. A very small amount of air flows through the channel, closed by a gravity damper, so that the firewood does not go out.
  3. 3. When the temperature sensor detects that the coolant in the boiler tank has cooled, the fan will automatically turn on and the process will repeat.

  With the help of automation, several modes of air injection are carried out in accordance with the wood used, which varies in quality and humidity. The standard type of boiler has the following technical characteristics:

  • rated power - 22 kW;
  • efficiency - 77%;
  • maximum operating pressure - 3 bar;
  • firebox depth - 460 mm;
  • the size of the opening where the firewood is placed is 36 by 25 cm;
  • chamber volume - 112 l;
  • Burning time with wood fuel is approximately 8 hours.

  The boiler has a simple design: an elongated firebox, equipped with grates at the bottom, and a heat exchanger at the top, consisting of 4 pipes and placed inside the tank. The forced air enters the ash chamber through a channel made of a 60 by 40 mm profile. To protect against dirt and dust, the automatic unit and fan are located on top of the boiler.

  Types of solid fuel boilers

  

  Top combustion heater

  The design of long-burning hot water boilers is the same furnace, supplemented with a water jacket. The principle of operation of the boiler is considered relatively new and consists in supplying air from above (where the combustion zone is) through a pipe, at the end of which a heavy metal disk is welded. As the wood burns, it sags under the weight of the load, and air flows move in a natural way due to the draft of the chimney.

  Based on user reviews, long-burning devices of this type are not particularly popular. Here are some reasons:

  • efficiency is inferior to classical types due to the location of the intense combustion zone in one plane;
  • the difficulty of filling the firebox with firewood - it is necessary for the previous portion of fuel to be completely heated;
  • impossibility of quickly extinguishing, if necessary.

  There are some shortcomings, but you can independently add something to the equipment or correct it. For example, to make a zonal chamber, mount the bottom and grate bars. You can eliminate the disadvantages of additional fuel loading by placing an additional door between the fuel opening and the ash chamber.

  

  Pyrolysis models

  Pyrolysis boilers operate with a phased separation of the combustion process, which increases efficiency and extends the period of operation of the generator. The firebox of the pyrolysis device is divided by a special nozzle: in the first chamber, wood burns, releasing gas, in the second, wood decay products are burned. And at the same time, a minimal amount of ash remains, and soot does not accumulate in the chimney.

  Pyrolysis units are used for heating private houses with an area of ​​more than 100 square meters. m. On one load of firewood it can function for about two days. The price of the product depends on the manufacturer’s brand, as well as on the power and degree of automation the unit is equipped with. Making such a long-burning boiler with your own hands is more difficult than a regular one with a simplified design, but it is possible.

  Wood-fired pyrolysis boilers for heating a private home

  Mine heat generator

  The difference between a mine unit and others lies in the duration of combustion and the features of its design. It is equipped with a large fuel chamber, so it does not require frequent loading of fuel, combustion takes place in a slow mode. There are two types of such boilers: with conventional combustion and pyrolysis. They have a similar device; they are equipped with two chambers: the first is designed to burn fuel, and the second is equipped with a heat exchanger.

  
  

  The device of a fuel device with normal look combustion is simpler. The main part of its body is a capacious loading chamber, it is called a shaft. When positioned vertically, it can hold a large amount of fuel. There is a hatch on the side or top for storing firewood.

  If you look into the combustion chamber, you will find that it resembles a shaft, hence the name of the boiler. Under the combustion chamber there is an ash pan, separated from it by a grate. Through the door you can access the ash pan, as well as the firebox. Using a damper located under the door, you can regulate air access.

  The second part of the boiler is a chamber with a built-in heat exchanger, which is filled with water. If the unit will not be used to heat the house with water heating, a fire tube heat exchanger is used. Gases from the firebox enter the chamber with a heat exchanger through an opening, heat the water in it and are eliminated through the chimney. Hot water flows through pipes into the heating system, and heated air into the room.

  The design of a shaft-type pyrolysis boiler is almost the same. However, in it there are some additional elements:

  1. 1. Two chambers, in one of which fuel burns, and in the other, carbon monoxide burns out.
  2. 2. Several perforated pipes through the holes of which air enters, enriching the combustion and afterburning chambers.
  3. 3. Valves that separate the chambers.

  The operating principle of the pyrolysis apparatus is somewhat different. The combustion process occurs with limited air flow, therefore, slowly and with the release of large quantity gas. It enters additional chambers through perforated pipes and burns there. Such boilers are used with any type of solid fuel: coal, firewood, pellets.

  One stack of firewood can heat a room for 30 hours, and a portion of coal can heat a room for up to 5 days. With complete combustion of fuel and its decay products, the generator achieves high efficiency - up to 90%.

The tube heat exchanger, which is not easy to manufacture, is endowed with the greatest efficiency. The dimensions are determined directly by the manufacturer.

On durable concrete foundation a blower chamber with a grate is installed. Then a heat exchanger is installed and surrounded by quality bricks. During the laying process, two doors are built in. The lower one is mounted at a level convenient for laying and burning firewood, as well as for cleaning the firebox and ash pan from ash. Through the upper door, which can be placed on the front surface of the device or on top in the form of a hatch, firewood, coal or pellets are loaded.

The heat exchanger must be positioned so that the outlet of the hot coolant is located in the very high point. It hinders education air jams in the system, thereby improving water circulation. The brickwork should be done with bandaging of the seams for greater strength of the walls, which should protrude 3 cm above the heat exchanger. The chimney can be made of brick or a metal one can be installed.

Pros and cons of heating with wood

Homemade wood-burning structures are often used for heating both small country houses, as well as large private households, near which there are no gas mains. The premises are heated with wood or coal.

Due to the high cost of coal, users prefer wood fuel on which the units operate with such advantages:

1. 1. Permission is not required to perform installation and operation of equipment.
2. 2. Cheap operation when compared with electric heating. And if there is a source of free firewood, the funds are spent only on material for assembling the heating apparatus.
3. 3. Heating does not depend on electricity - this applies to the simplest units that are not equipped with electrical components.
4. 4. The ability to use long-term combustion, allowing you to reduce approaches to replenish fuel.
5. 5. Cheap assembly. The cost of a self-made device will be lower than its factory counterpart.

Only with constant cleaning of the equipment and performing scheduled repairs will the devices operate stably and efficiently throughout the entire period of operation. But There are also disadvantages of hand-made solid fuel boilers:

1. 1. The difficulty of making a homemade boiler, especially with a heating circuit.
2. 2. Assembly errors may occur, which will affect the efficiency of the device.
3. 3. They do not look particularly attractive, although this depends on the skill of the manufacturer.

Undoubtedly, aesthetics own production cannot be compared with the design of factory equipment. However, the assembled structure meets the requirements of its own heating system. It should also be taken into account that the assembled heat generator will be at least two times cheaper than the factory one.

Manufacturing of solid fuel boiler with my own hands- a complex and responsible event that requires careful preparation. It is necessary to know production technology, possess welding and metal working skills. By following the main rules of boiler development, you will create a heating device quickly and at minimal cost.

Description and principle of operation of a solid fuel boiler

General view of the boiler

A long-burning solid fuel boiler is a large firebox with a limited solid fuel combustion area and a controlled supply of oxygen. The operating principle of the device is based on the ability of solid fuel elements to smolder for a long time with increased heat transfer.

A large amount of solid fuel is loaded into the furnace on average 1–2 times a day, but there are units that can operate for several days. By regulating the flow of oxygen into the combustion zone, slow smoldering occurs at elevated temperatures. The smoke is discharged through a special pipe. It passes through the heat exchanger and warms up the water for the heating system. Timely loading of the firebox ensures almost continuous operation of the device.

Fuel combustion in a long-burning boiler often occurs from top to bottom. In this case, as the top layer burns out, the fire moves lower to the next layers. Such thermal units have many advantages that ensure their popularity among all groups of the population:

1. Increased firebox volume for loading fuel.
2. Long life on a single load.
3. Great heat dissipation.
4. Environmentally friendly. During operation, the heater emits a minimal amount of exhaust gases.

Standard long-burning boilers differ in the type of fuel used:

1. Devices operating on one type of fuel. Typically, this is used as firewood, sometimes as pallets obtained from waste from the wood processing industry.
2. Universal units. Here it is possible to combine several types of solid elements - firewood, sawdust, pallets.

Based on the type of operation, all existing types of long-term combustion boilers can be divided into two large groups:

1. Pyrolysis. The operation of such devices uses the principle of pyrolysis. Solid fuel particles burn out at high temperatures and poor oxygen supply. The process produces gas, which is sent to a separate compartment where it burns. This principle increases the boiler efficiency and fuel combustion time.
2. Classic. They have a simplified design, differ in the volume of the firebox, the combustion method, the presence of a water jacket circuit, etc. The simplest classic boiler without a jacket is a metal container made of a pipe or barrel, where solid particles are burned according to the “top to bottom” principle.

The scope of use of solid fuel boilers is extensive. Household models heat private households, shops and similar residential and non-residential facilities. Large industrial units, which require a separate equipped room, can heat a small plant. The popularity of boilers is due to their low cost and ease of operation.

Unit design

Main components of the heating device

Briefly, the essence of the work and the design of a long-burning solid fuel pyrolysis boiler can be summarized as follows:

1. Two metal cylindrical housings of different sizes are fastened together. The smaller one is the firebox where solid particles are burned. Larger - outer shell boiler
2. The remaining space between the housings is filled with water. It acts as a coolant.
3. An air distributor is installed in a small pipe and divides it into two parts. In one section, fuel particles are burned, in the other, afterburning of pyrolysis gas occurs. The distributor is made in the form of a telescopic pipe, to one end of which a small disk with blades is attached. This allows the gases released during fuel combustion to be evenly distributed. Through the air distributor, oxygen is supplied to the combustion compartment, which is necessary to maintain combustion.
4. As the fuel layers burn out, the distributor moves lower and adds air to the lower levels.
5. If the process is controlled by automatic control systems, it is necessary to ensure that the devices are connected to the electrical network.

You can make a simple cauldron with your own hands

To manufacture a solid fuel boiler, it is necessary to develop a drawing or diagram. It displays an approximate appearance unit in compliance with all proportions, parts and elements.

All components and parts of an industrial boiler are indicated with dimensions

Tools and materials

Let's take a closer look at creating a long-burning pyrolysis boiler with your own hands. It operates on gas obtained from dried firewood or waste compressed into pallets.

In progress self-made A solid fuel boiler will require a set of power tools and materials, as well as a drawing or diagram showing all the necessary parts and dimensions.

Required equipment:

1. Welding machine and several packs of working electrodes.
2. Angle grinders. It is advisable to have two - large and small. If there are none, the work can be carried out using ordinary electric jigsaw, however, the operating time will increase.
3. Cutting and grinding wheels with a diameter of 125 and 230 mm, in the absence of grinders - metal files for a jigsaw.

Necessary materials:

1. Pipe with a large diameter (about 50 cm). Length - 130 cm, wall thickness - from 3 mm.
2. A pipe with a smaller diameter, about 45 cm. Length - one and a half meters, wall thickness - from 3 mm. If there are no pipes, you can purchase several metal sheets 1250 * 2500 * 2.5 mm, roll them in a specialized company and manufacture necessary pipes independently using a welding machine.
3. Thin long pipe. Diameter - about 6 cm, length - 120 cm.
4. A metal sheet from which the loading door and hatch for ash removal will be cut.
5. Metal rings with a diameter of half a meter and a width of about 2.5 cm.
6. Door fittings - hinges, latches, etc.
7. Asbestos sheet. It is placed in the boiler door. This prevents overheating and reduces heat loss.
8. Asbestos cord. They seal the fuel compartment door and the ash pan hatch.

Step-by-step manufacturing instructions

The process of creating a heating device is quite simple and takes place in several successive stages.

First, the body of the structure is made:

1. Two pipes large diameter(50 and 45 cm) are nested inside each other and connected using a metal ring.
2. A circle of metal with a diameter of 45 cm is cut out of a pre-prepared sheet, which is used to weld the bottom of a smaller pipe located inside the structure. As a result, we get a barrel with a diameter of 45 cm, with a welded hot water jacket-contour 2.5 cm wide.
3. A rectangular hole is cut at the bottom of the “barrel”. Height - up to 10 cm, width - about 15. It will be used as an ash pan door. A hatch is welded in, a door with attached hinges and a latch is installed.

   The ash pan door is cut through at the bottom

4. A rectangular hole is cut in the upper part of the circuit to supply solid fuel. The size is selected individually, the main condition is the convenience of loading firewood. The hatch is welded. A door equipped with hinges and a latch is installed. It is made double: an asbestos layer is laid between individual metal sheets, and the contact areas are sealed with asbestos cord. Thanks to such manipulations, heat loss from the boiler is reduced.

   The size should be sufficient for storing firewood

5. At the upper level, an exhaust pipe is installed that discharges exhaust gases into the chimney.

   A smoke exhaust pipe is welded to the nozzle

6. In two places (top and bottom) of the water circuit, pipes with a diameter of 4–5 cm are welded, necessary to connect the boiler to a further heating system. The thread is cut, for which a groove is used.
7. Examination welding seams, if necessary, eliminate flaws.

After creating the metal body of the solid fuel boiler, you can begin to manufacture and install the air distributor:

The air distributor can be made in the form of a pancake with welded channels

This is one of the simplest ways to make a solid fuel boiler. There are complicated circuits used in industrial and household models.

Video: Assembling a solid fuel boiler

Design features of pyrolysis units

The manufacture of a long-burning pyrolysis solid fuel boiler follows a similar pattern: welding of the body, air distributor, installation of fittings, etc. The main difference from the classic device is the presence of two chambers. In the first, fuel burns, in the second, pyrolysis gases burn out. For such a boiler it is very important to ensure a constant flow of oxygen. This can be done using a fan.

Solid fuel pyrolysis boilers with a lower combustion chamber differ in their design and fuel combustion features.

1. In supercharged models, air is pumped by a fan. In the lower chamber there is high blood pressure. In such a boiler you can use any household fan, right down to the computer cooler, the main thing is to exclude very strong supercharging.
2. In boilers with a smoke exhauster it is installed exhaust fan, creating insufficient pressure. The most complete combustion of gases and optimal operation of the device are ensured.

Pyrolysis units with an upper chamber are considered more productive. They ensure slow and uniform burning of fuel. Some industrial wood boilers can work for about two days. When laying the same portion of coal, the operating time increases to a week.

Video: Features of work

Installation of a homemade boiler and accelerating furnace

Installation of the heating system may require a specially equipped location. It is not recommended to install such a structure in residential premises: it increases the risk of fires and leaks. The relevant services may impose a fine. Often homemade units installed in greenhouses, technical and work rooms.

When installing a solid fuel boiler, you should be guided by some requirements:

1. The distance from the boiler to the walls should be more than 25 centimeters. This minimizes the risk of fire and improves air exchange in the room.
2. It is advisable to equip your own non-combustible foundation under the boiler. You can lay an asbestos or concrete slab.
3. In a room with an installed pyrolysis solid fuel boiler there must be high-quality ventilation system. A constant supply of fresh air is necessary for the operation of this type of heating system.
4. To avoid leaks and fires, the chimney through which the exhaust gas escapes must be insulated. As an insulating material, you can use regular foil or mineral wool.

After assembling and installing the solid fuel boiler, it is necessary to perform a test loading, called the accelerating furnace. Load fuel for the first time before starting heating season. If malfunctions are detected, there will be some time left before the system is restored to its proper state.

A solid fuel boiler can operate on almost any fuel. For the accelerating furnace, you should use the type of fuel that is planned for constant loading.

The firebox is filled completely, up to the outlet pipe. To help the fuel burn better, you can spray a little standard lighter fluid. The boiler is ignited using a long wood chip or splinter through an open damper. Until the loaded fuel begins to smolder, the damper cannot be closed. Then you can cover it. If the combustion rate is not sufficient for optimal performance heating device, the damper opens slightly to improve draft. During the first combustion, loaded solid fuel should burn out completely. The fact that stable smoldering has begun can be recognized by the smoke emerging from the chimney. During combustion separate layers

fuel, the air distributor pipe will lower, and the smoldering rate can also be determined from it.

Making a long-burning boiler yourself is a reality that is available to everyone, regardless of whether you are new to making it or not. The main thing is not to forget about fire safety: after all, every heating device is a potentially dangerous device.