Drawing of a solid fuel boiler with upper combustion. Solid fuel boiler for long burning: warmth and comfort with your own hands

Installation

The long-burning boiler is put on flat surface and regulate according to the level, in case of a strong skew, the circulation of the coolant may deteriorate.

The air distributor is placed inside the furnace, and a lid is put on top, which is fixed on the body by welding or tight fitting with an asbestos cord seal.

Connect the flue pipe to the chimney. Pipes of the heating system are connected to the pipes of the water jacket.

After filling the system, the boiler can be started to heat. A trial furnace is performed with an incomplete batch of fuel, the modes are adjusted, and only after that it can be loaded to work at full capacity.

Such a boiler, with a modest appearance, is quite capable of heating a village or country house, workshop, garage, solving the problem of heating.

Production of a solid fuel boiler with my own hands- a complex and responsible event that requires careful preparation. It is necessary to know the production technology, to have the skills of welding and working with metals. Following the main rules for the development of boilers, 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 solid fuel boiler for long burning is a large furnace with a limited solid fuel combustion zone and a controlled supply of oxygen. The principle of operation of the device is based on the ability of solid fuel elements to smolder for a long time with increased heat transfer. In the process, the substance is completely burned out with minimal waste generation.

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

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

1. The increased volume of a fire chamber for loading of fuel.
2. Long service life on a single load.
3. Great heat dissipation.
4. Environmental friendliness. During operation, the heater emits a minimum amount of exhaust gases.

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

1. Devices that operate on the same type of fuel. Usually firewood acts in this capacity, sometimes pallets obtained from the waste of the woodworking industry.
2. Universal units. Here it is possible to combine several types of solid elements - firewood, sawdust, pallets.

According to the type of work, all existing types of long-term combustion boilers can be divided into two large groups:

1. Pyrolysis. In the operation of such devices, the principle of pyrolysis is used. Solid fuel particles burn through at high temperatures and low oxygen supply. In the process, gas is produced, which is sent to a separate compartment, where it burns. This principle increases the efficiency of the boiler and the burning time of the fuel.
2. Classic. They have a simplified design, differ in the volume of the furnace, the method of combustion, 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-down” principle.

The scope 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 the low cost and ease of operation.

Unit device

The main components of the heating device

Briefly, the essence of the work and the device of a solid fuel pyrolysis boiler for long burning can be reduced to the following:

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

A simple boiler can be made with your own hands

For the manufacture of a boiler operating on solid fuel, it is necessary to develop a drawing or diagram. It displays an example appearance unit in compliance with all proportions, details and elements.

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

Tools and materials

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

In the process self-manufacturing 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 sizes.

Required equipment:

1. Welding machine and several packs of working electrodes.
2. Angle grinders. It is desirable to have two - large and small. If there are none, the work can be done using a conventional electric jigsaw, but the work 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. In the absence of pipes, you can purchase several metal sheets 1250 * 2500 * 2.5 mm, roll them in a specialized company and manufacture the right pipes independently with the help of a welding machine.
3. Thin long pipe. Diameter - about 6 cm, length - 120 cm.
4. metal sheet to be cut loading door and an ash hatch.
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 laid in the boiler door. This eliminates their overheating and reduces heat loss.
8. Asbestos cord. They seal the fuel compartment door and the ash hatch.

Step by step instructions for making

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 large diameter pipes (50 and 45 cm) are inserted into each other and connected with a metal ring.
2. From a pre-prepared sheet, a circle of metal with a diameter of 45 cm is cut out, with which the bottom of a smaller pipe located inside the structure is welded. 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 valve 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 for supplying 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 the individual metal sheets, the contact points are sealed with an asbestos cord. Thanks to such manipulations, the heat loss of the boiler is reduced.

   The size should be sufficient for laying firewood

5. At the top level, an exhaust pipe is equipped that removes 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, which are necessary to connect the boiler to a further heating system. A thread is cut, for which a lerka is used.
7. Inspection of welding seams, if necessary - elimination of flaws.

After creating the metal body of the solid fuel boiler, you can proceed to the manufacture and installation of 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 out, in the second, pyrolysis gases burn out. For such a boiler, it is very important to ensure a constant supply of oxygen. This can be done with a fan.

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

1. In supercharged models, air is forced by a fan. In the lower chamber there is high blood pressure. In such a boiler, you can use any household fan, up to a computer cooler, the main thing is to exclude a very strong boost.
2. In boilers with a smoke exhauster, an exhaust fan is installed that creates insufficient pressure. Provided with maximum complete combustion gases and optimal operation of the device.

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

Video: Features of work

Installation of a homemade boiler and an accelerating furnace

To install the heating system, a specially equipped place may be required. It is not recommended to install such a structure in residential premises: the risk of fires and leaks increases. The relevant authorities may impose a fine. Very often, home-made units are installed in greenhouses, technical and workrooms.

When installing a solid fuel boiler, some requirements should be followed:

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

After assembling and installing a solid fuel boiler, it is necessary to make a test load, called an accelerating furnace. Load fuel for the first time before starting heating season. In case of malfunctions, there will be some time left before the system is brought into proper condition.

A solid fuel boiler can operate on almost any fuel. For an accelerating furnace, you should use the type of fuel that is planned for constant loading. The furnace is filled completely, up to the outlet pipe. To make the fuel burn better, you can sprinkle a little standard ignition fluid.

The boiler is ignited with a long wood chip or a torch, through an open damper. Until the smoldering of the loaded fuel has begun, the damper must not be closed. Then it can be covered. If the combustion rate is insufficient for optimal operation of the heating device, the damper opens slightly to improve draft. During the first combustion, the loaded solid fuel must completely burn out. The fact that stable smoldering has begun can be recognized by the smoke that appeared from the chimney. During the combustion of individual layers of fuel, the air distributor pipe will descend, it can also be used to determine the rate of smoldering.

Self-manufacturing of a long-burning boiler is a reality that is available to everyone, regardless of whether you are new to its manufacture or not. The main thing is not to forget about fire safety: after all, every heater is a potentially dangerous device.

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“A boiler is really a stove in a barrel of water” ... and the efficiency of such a unit will be in best case 10%, or even 3-5%. Some kind of, but 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 process of combustion of solid fuel, in contrast to gas or combustible liquids, will certainly stretch in space and time. Gas or oil can be completely burned immediately in a small gap from the nozzle to the diffuser of the burner, but wood-charcoal cannot. Therefore, the requirements for the design of a solid fuel heating boiler are different than for heating furnace, it’s impossible to just put a water heater of the heating circuit into it in continuous circulation. Why is this, and how should a continuous heating boiler be arranged, and 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 rising in price, and in return, inexpensive alternative fuels appear on the market, 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 that the transition to individual heating will allow to get rid of energy losses in the mains of the CHP and power transmission lines, and they are by no means small, up to 30%

You can’t do a gas boiler yourself, if only because no one will give permission for its operation. It is forbidden to use individual liquid fuel boilers for heating residential premises due to their high fire and explosion hazard in decentralized use. But a solid fuel boiler can be made with your own hands and formalized, just like a heating stove. This is perhaps the only thing they have in common.

Features of solid fuel

Solid fuel does not burn very quickly, and not all components that carry thermal energy burn out in its visible flame. For complete combustion of flue gases, a high, but quite certain temperature, otherwise conditions will arise for the occurrence of endothermic reactions (for example, nitrogen oxidation), the products of which will carry away the energy of the fuel into the pipe.

Why doesn't the boiler bake?

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

The body of the furnace is, therefore, 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, because of this, in one way or another, its internal heat balance will be disturbed, 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 DHW storage tank. Also, the furnace does not need operational adjustment of its thermal power, it is enough to load the fuel based on the required hourly average for the time between heatings.

A water boiler, no matter what fuel, is a continuous device. The coolant in the system circulates all the time, otherwise it will not heat up, and the boiler must at any given moment give exactly as much heat as it has gone outside due to heat loss. That is, the fuel must be either periodically loaded into the boiler, or the thermal power must be promptly regulated 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 burnt out, otherwise the energy of the fuel will settle on the register with soot, which will also need to be cleaned.

Finally, if the furnace 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, its fire hazard is much higher than that of stoves.

Note: an individual boiler room of a residential building must have a volume of at least 8 cubic meters. m, ceiling not less than 2.2 m high, opening window not less than 0.7 sq. m, a constant (without valves) influx of fresh air, a smoke channel separate from other communications and a fireproof interchange from the rest of the rooms.

From this it follows, firstly, boiler furnace requirements:

• It must ensure rapid and complete combustion of the fuel without a complex convection system. This can only be achieved in a furnace made of materials with the lowest possible thermal conductivity, because. for the rapid combustion of gases is required high concentration heat.
• The furnace itself and the parts of the structure associated with it in terms of 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, an ordinary furnace furnace for a boiler will not work, some kind of special one is needed.

Heat exchange register

The heat exchanger is the most important unit of the heating boiler, it basically determines its efficiency. According to the design of the heat exchanger, the entire boiler is called. In domestic 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 furnace in it. A jacketed boiler can also be quite economical on one condition: if the combustion in the furnace is flameless. A fiery 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. As a result - efficiency up to 15% and increased soot deposition, and even acid condensate.

Horizontal registers, generally speaking, are always inclined: their hot end (supply) must be raised above the cold one (return), otherwise the coolant will reverse, and the failure of forced circulation will immediately lead to a severe accident. In vertical registers, the pipes are arranged vertically or in a slight slope to the side. Both here and there pipes, so that gases “get tangled” better in them, are arranged in rows in a checkerboard pattern.

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

1. Flowing - gases pass generally perpendicular to the flow of the coolant. Most often, such a scheme is used in horizontal industrial boilers of high power for the sake of their lower height, which reduces the cost of installation. AT household situation it turns out the opposite: in order for the register to properly capture the heat, it has to be made stretched upwards above the ceiling.
2. Countercurrent - gases and coolant move along the same line towards each other. Such a scheme gives the most efficient heat transfer and the highest efficiency.
3. Flow - gases and coolant move in parallel in one direction. It is rarely used in boilers for special purposes, because. In this case, the efficiency is poor, and the equipment wear is high.

Further, the heat exchangers are fire-tube and water-tube. In fire tubes, smoke tubes with flue gases pass through a water tank. Fire tube registers work stably, and vertical ones give good efficiency even in a flow circuit, because. internal water circulation is installed in the tank.

However, if we calculate the optimal temperature gradient for transferring heat from gas to water based on the ratio of their density and heat capacity, then it turns out to be approximately 250 degrees. And to push this heat flow through the wall steel pipe 4 mm (less than it is impossible, it will burn out very quickly) without noticeable losses in the thermal conductivity of the metal, about 200 degrees are needed. As a result, the inner surface of the smoke tube must be heated to 500-600 degrees; 50-150 degrees - operating margin for fuel water cut, etc.

Because of this, the service life of the fire 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 the hot gases entering the register and those leaving 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 furnace does not exceed 1100-1200 degrees. According to the Carnot formula, it turns out that you cannot get an efficiency higher than 63%, and even the efficiency of the furnace is not more than 80%, so the total is 50%, which is really bad.

In small domestic boilers, these features are less pronounced, because. with a decrease in the size of the boiler, the ratio of the surface of the register to the volume of flue gases in it increases, this is the so-called. square-cube law. In modern pyrosis boilers, the temperature in the combustion chamber reaches 1600 degrees, the efficiency of their furnace is under 100%, and the registers of branded boilers are guaranteed for 5 years or more only made 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 for fire tubes is generally unsuitable, it cracks.

In water-tube registers, the coolant flows through pipes placed in a fire chamber, where hot gases enter. Now the temperature gradients and the square-cube law act in reverse: 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, ordinary steel pipes serve for a long time and the boiler efficiency is about 80%.

But horizontal flow-through water tube boilers are prone to the so-called. "bubble". The water in the lower pipes is much hotter than in the upper ones. It is pushed through to the supply in the first place, the pressure drops, and the colder upper pipes “spit out” the water. "Whipping" not only gives noise, warmth and comfort as much as a neighbor - a drunkard and a brawler, but is also fraught with an impulse in the system due to water hammer.

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

About the heat exchanger capacity

The ratio of the capacities of the heat exchanger 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 take in 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.

Too small a register is prone to boiling and requires precise, quick adjustment of the furnace power, which is unattainable in solid fuel boilers. A large-capacity register takes a long time to warm up, and in case of poor external thermal insulation the boiler or its absence loses a lot of heat, and the air in the boiler room can warm up above the permissible fire safety and boiler specifications.

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

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

What is a heat exchanger made of?

Cast iron as a material for the 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 will not pass through the cast iron into the water as needed.
• The large heat capacity of cast iron is also its minus: the boiler must quickly give off heat to the system before it escapes somewhere else.
• Cast iron heat exchangers do not fit into modern requirements in terms of weight and dimensions.

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

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

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

• With a boiler power of up to 12 kW, a bypass valve between the boiler supply and return is sufficient.
• With a higher power and / or a heated area of ​​more than 160 sq. m, an elevator assembly is also needed, and the boiler must operate in the mode of overheating water under pressure.

The bypass valve is controlled either electrically from a temperature sensor or non-volatilely: from a bimetallic plate with a rod, from wax melting in a special container, etc. As soon as the return temperature drops below 70-75 degrees, it lets in hot water from submission.

The elevator unit, or simply the elevator (see Fig.) acts the other way around: the water in the boiler is heated to 110-120 degrees under pressure up to 6 atm, which eliminates boiling. To do this, the combustion temperature of the fuel is increased, which increases the efficiency and eliminates condensation. And before being fed into the system, hot water is diluted with a return pipe.

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

Circulation and boiler

Thermosiphon (gravitational) 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 a drain valve is opened with a full expansion tank, water will rush 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 motion in a thermosiphon system is scanty. Therefore, the efficiency of the boiler as a whole falls.

But the circulation pump needs electricity (50-200 W), which can be lost. UPS (uninterruptible power supply) for 12-24 hours of battery life is very expensive, so a properly designed boiler is counted on forced circulation, and in the event of a power outage, it must switch to thermosiphon mode without outside interference when the heating is barely warm, but still warms.

How is the boiler installed?

From the requirement of the minimum own heat capacity of the boiler, its small weight compared to the furnace and the weight load from it per unit floor area directly follow. As a rule, it does not exceed the minimum allowable according to SNiP for flooring 250 kg / sq. m. Therefore, the installation of the boiler is permissible without a foundation and even parsing 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 installation site of the boiler to concrete screed with a side extension of at least 150 mm. The base under the boiler is covered with asbestos or basalt cardboard 4-6 mm thick, and a sheet of roofing iron 1.5-2 mm thick is placed on it. Further, if the flooring was disassembled, the bottom of the boiler is bricked up with a cement-sand mortar to the floor level.

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

For a solid fuel boiler, a separate boiler room is required. The requirements are listed above. In addition, almost all solid fuel boilers do not allow power adjustment over a wide range, so they need a full-fledged piping - a kit additional equipment ensuring efficient and trouble-free operation. We will talk about it further, but in general the boiler piping is a separate big topic. Here we mention only the immutable rules:

1. The installation of the piping is carried out in countercurrent to the water, from the return to the supply.
2. At the end of the installation, its correctness and quality of the connections are checked visually according to the scheme.
3. The installation of the heating system in the house is started only after tying the boiler.
4. Before fuel loading and, if required, power supply, the entire system is filled with cold water and all joints are monitored for leakage during the day. In this case, water is water, and not some other coolant.
5. If there are no leaks, or after they are eliminated, the boiler is started on water, continuously monitoring the temperature and pressure in the system.
6. Upon reaching the nominal temperature, 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, the system is allowed to cool completely.
8. Drain the water, fill in the regular coolant.
9. Once again, the joints are checked for leakage for a day. If everything is in order, start the boiler. No - eliminate leaks, and again daily control 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

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

Wood burning in the house

A home wood-burning boiler can only be of long burning, otherwise it beats it in all respects. Industrial structures, eg. 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 work both on coal and on any solid fuel, except for sawdust, but on coal, fuel consumption will be much higher: heat transfer from one load is 60-72 hours, and for specialized coal - up to 20 days.

However, a long-burning wood-burning boiler can be useful in places where there is no regular delivery of coal and a qualified heat engineering service. It costs one and a half times cheaper than coal, its shirt 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 the smoldering of fuel with a thin layer and a rather large volume of the jacket, boiling of water is excluded, so the binding is quite the same as for titanium. Connecting a long-burning wood-fired boiler is also no more difficult than titanium, and can be done independently by an unskilled owner.

About brick boilers

Scheme of the device of the boiler "Blago"

Brick is a friend of the furnace and an enemy of the boiler due to the fact that it gives the structure a large thermal inertia and weight. Perhaps the only brick boiler in which the brick is in its place is the pyrolysis "Blago" Belyaev, the diagram in fig. And then, its role here is completely different: the lining of the combustion chamber is made of fireclay bricks. Heat exchanger water-tube horizontal; the problem of coiling is solved by the fact that the register pipes are single, flat, elongated in height.

Belyaev's boiler is really omnivorous, and 2 separate bunkers are provided for loading different types fuel without stopping the boiler. On anthracite "Blago" can work for several days, on sawdust - up to a day.

Unfortunately, the Belyaev boiler is quite expensive, because of the fireclay lining it is poorly transportable and, like all pyrolysis boilers, requires complex and expensive piping. Its power is regulated within a small range by flue gas bypass, so it will show good efficiency on average per season only in places with prolonged severe frosts.

About boilers in the furnace

The boiler in the furnace, about which so much is being said and written now, is a water-tube heat exchanger immured in the furnace masonry, see fig. below. The idea is this: the stove after heating should give off heat more to the register than to the surrounding 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 higher than 75%, and its area outer surface will be at least 10-12 square meters. m. The surface area of ​​the register is hardly 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%

The next moment - an oven with a register immediately loses its property. In no case should you drown it out of season with an empty register. The TC (temperature coefficient of expansion) of the metal is much greater than that of a brick, and the heat exchanger swollen from overheating will tear the furnace before our eyes. Thermal seams will not help the case, the register is not a sheet or a beam, but a three-dimensional structure, and it bursts immediately in all directions.

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

Boiler piping

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

The piping of solid fuel boilers of other types should provide a set of functions, which is better understood in fig. on right:

1. safety group: air drain cock, common pressure gauge and breakthrough valve to release steam when boiling;
2. emergency cooling storage tank;
3. its float valve, the same as in the toilet;
4. thermal valve for starting emergency cooling with its sensor;
5. MAG-block - a drain valve, an emergency drain valve and a 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 a three-way bypass valve electrically controlled by temperature;
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 in case of sudden warming, the entire system can overheat unacceptably, up to a gust. Then the thermal valve 4 starts tap water into the intercooler, and it cools the supply to normal.

Note: the master's money for fuel and water at the same time quietly flowing down the drain. Therefore, solid fuel boilers are unsuitable for places with mild winters and long off-seasons.

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 is turned off, the thermal valve closes. As much water enters the heating radiators as they let through in the thermosyphon mode, if only it was possible to live in the rooms. But the intercooler thermal valve opens completely (it is kept closed under voltage), and the excess heat again takes the owner's money into the drain.

Note: if water is lost along with electricity, the boiler must be urgently extinguished. When the water from tank 2 flows out, the system will boil.

Boilers with built-in overheating protection are 10-12% more expensive than conventional ones, but this more than pays off by simplifying the piping and increasing the reliability of the boiler: excess superheated water is poured into an open large-capacity expansion tank, see Fig. return line. The system, except for the circulation pump 7, is non-volatile and goes into the thermosiphon mode smoothly, but with a sudden warming, the fuel is still wasted, and the expansion tank must be installed in the attic.

As for pyrolysis boilers, then typical scheme their bindings are given for reference only. Anyway, its professional installation will cost only a small part of the cost of the component. For reference: a 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 generally calculated in the same way as stoves. General principle: too narrow a chimney will not give the desired draft. For the boiler, this is especially dangerous, because. it is heated continuously and the waste can go at night. Too wide a chimney leads to a “whistling”: cold air descends through it into the furnace, chilling the stove or register.

The boiler chimney must meet the following requirements: the distance from the roof ridge and between different chimneys is at least 1.5 mm, the upward extension 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. At each break in the chimney outside the boiler room there must be a cleaning door, each passage of the pipe through the ceiling must be thermally insulated. The upper end of the pipe must be equipped with an aerodynamic cap; for the chimney of the boiler, it, unlike the stove, is mandatory. Also, a condensate collector is required for the boiler chimney.

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

According to such graphs, after an accurate calculation according to local data, it is possible to estimate whether there was blunder. If the calculated point is somewhere around its generalized curve, the calculation is correct. In extreme cases, you will have to build up or cut the pipe by 0.3-0.5 m.

Note: if, say, for a pipe with a height of 12 m there is no curve for a power of 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 you need to calculate exactly according to local data.

Video: an example of the construction of a mine-type solid fuel boiler

conclusions

The depletion of energy resources and the rise in fuel prices have radically changed the approach to the design of domestic heating boilers. Now they, like industrial ones, require high efficiency, low thermal inertia and the ability to quickly control power over a wide range.

Nowadays heating boilers according to the basic principles laid down in them, they finally parted ways with furnaces and divided into groups for different climatic conditions. In particular, considered solid fuel boilers are suitable for areas with a harsh climate and prolonged severe frosts. For places with a different climate, other types of heaters will be preferable.

In an effort to save on heating, many homemade "masters" make various devices. A do-it-yourself boiler, which can often be seen in a private house, is one of such useful devices.

There are various varieties of it. If you have the skills to work with a welding machine and metal, then you can save a lot on arranging heating.

Varieties

Before the direct manufacture of a boiler for heating in a house, it is necessary to determine its configuration and type. According to the type of heating of the coolant, boilers are:

• Gas;
• Wood;
• Coal;
• Electrical;
• Pyrolysis;
• Oily;
• Pellet

As for the configuration, it can be any:

• round;
• Rectangular;
• Trapezoidal;
• Tapered

How to make a boiler

In the design process, it is necessary to take into account some design features, the principle of its operation. In particular, you need to decide on the purpose of the boiler, what type it will be. The easiest way is to make a solid fuel boiler with your own hands.

Much more difficult, almost impossible - gas, as it is subject to increased safety requirements. You need to get permission to use it, check it. And - if all the characteristics of the device do not meet the requirements, then the relevant authorities will simply prohibit such a boiler from operation.

The efficiency of the boiler is affected by both the design (coolant capacity) and the rate of fuel combustion, a constant supply of fresh air (oxygen). It should be noted that the fuel burns completely and an outflow of gas is possible, which carries a lot of heat, which must be prevented.

Some Features

The configuration of the boiler, its characteristics, drawings will depend on many factors:

• material. Ordinary steel (sheet) is suitable, but heat-resistant stainless steel or cast iron is best.
• Possibilities of good steel processing, reliable connection of structural parts. Usually for this they use mainly a grinder, a gas cutter and electric welding.
• Type, characteristics of fuel (liquid or solid). Steel must withstand high temperatures, do not deform, do not melt under their influence. Withstand the internal pressure of vapors and gases without gaps and cracks.
• Correct calculation of the method of circulation of the coolant. Will it be natural (due to the correct manipulation of pipe diameters, their slope, tank height, etc.) or forced (using a pump in the circuit).
• Accounting for vapor pressure, the use of valves to discharge excess gases, condensate (return installation).

It is important to carefully consider everything in the process of designing a boiler, including it in the heating circuit. What and how will work after assembly.

Making a heating boiler with your own hands is not so difficult. All problems usually begin later, when something is not taken into account or clumsily done.

Wood fired water boiler step by step

To make it, we need:

• Protective gloves;
• overalls;
• Welding mask;
• electrodes;
• Welding machine;
• Drill;
• Drills for metal;
• Roulette;
• Material for the manufacture of the boiler (2 barrels or - a metal sheet(thickness - not less than 5 mm), doors, flaps, grille, corners)

The only significant drawback of a wood-burning boiler is low efficiency. But ease of manufacture and maintenance are its essential advantages, making it the most popular.

Manufacturing instructions

When there is everything you need (material and tools), it remains only to assemble the boiler in the following sequence:

• We take 2 barrels with different diameter, wall thickness not less than 4 mm;
• We cut out holes for the ash pan and water container with a grinder;
• We install one cylinder of smaller diameter inside the other;
• We weld a cover over them, an ash pan, a firebox;
• We close the door;
• We weld water pipes, branch pipe for check valve (pressure relief);
• We mount a grate inside the oven;
• We make a hole for the chimney;
• Installing the pipe
• We check tightness.

When there are no leaks in the boiler, it is connected to the heating system and the water supply network.

If used oil or antifreeze is used as a coolant, then they will be filled manually. Connection to the water supply, welding pipes is not necessary for this.

After installing the boiler with your own hands in the heating system, you need to check the correctness of its operation. A properly assembled device will heat the coolant (water or oil) during the combustion process. If he does this poorly, then you should check for air locks in the heating network, lower the vapor pressure by dumping them.

In any case, you need to understand the principle of operation of this kind of boiler so that there are no excesses and problems during its operation.

DIY boiler photo