Pyrolysis oven from a gas cylinder. Manufacturing Features

A homemade pyrolysis oven from a gas cylinder is one of the most popular manufacturing options. It captivates with its cheapness and simplicity. All materials can be easily found at any dacha.

It will not heat a large house, but for a small dacha, garage, greenhouse it is just right.

Such a stove can easily cope with heating a room of 100 m2. Often used for heating greenhouses, garages, warehouses. It does not require a foundation, but the foundation still needs to be prepared. At a minimum, level and cover with a metal sheet of at least 4 mm thickness.

It is also important to follow all fire safety rules during installation. The distance to combustible objects should not be closer than 50 cm. Wooden surfaces are additionally protected with fireproof cloth.

Recommendations for increasing the efficiency of a homemade stove

How to increase the efficiency of bubafoni? What problem is preventing this heat generator from working to its full potential? One of the problems is that the stove body heats up unevenly. Because of this, we get poor heat exchange in the room. Is it possible to solve this problem? Of course you can. To solve this problem, let's take a sheet of corrugated metal profile. We wrap it around the stove, obtaining a protective “shirt” and spot-weld the profile sheet to the cylinder.

You can find another solution besides welding. It's up to you to decide. By implementing this solution into a finished design, we will obtain a long-burning furnace device that forms rising air currents. Cold air will rise from the bottom of the ribs. After passing along the body of the cylinder, the air will heat up and become hot at the outlet. In addition to this modification, you can do the following.

Cover the entire structure with bricks. This will allow heat to accumulate from the generator, releasing it evenly over the entire area of ​​the building for quite a long time. In addition to the profile sheet, you can use pipe scraps. Profile or regular round pipes are suitable. They are welded around the cylinder body, resulting in an effective design for generating heat with uniform heating.

Requirements

If the oven is used for cooking food, then one important problem arises. There must be a surface where food will be placed. At the same time, the heat flow in this place should be sufficient for high-quality cooking.

If, first of all, the tasks of heating the room are important, then other features come to the fore. Here the following are of particular importance:

1. long burning;
2. fuel efficiency;
3. high requirements for fire safety.

The last requirement plays a vital role in the operation of various types of furnaces. However, when heating, the stove, in fact, can be left without direct supervision for a long time. This greatly increases the risk of an accidental fire. Another important issue is the possibility of legalizing a self-made stove. This process is not simple or easy.

Gas cylinder for pyrolysis furnace

It is not difficult to make a pyrolysis oven from a gas cylinder. What needs to be done for this.

Pyrolysis stove from a cylinder

First of all, inside the cylinder you need to make partitions for the afterburning chamber. To do this, you can cut circles from sheet iron with a diameter equal to the inner diameter of the cylinder. On each circle you need to cut out a segment. The end result should be more than a semicircle. The resulting parts are installed inside the tank, where they are electric welded around the perimeter

It is very important to install the cut circles correctly. It is necessary to carry out the installation so that the space free from the cut-off element is opposite exactly the same, only different cut-off circle

That is, you should get a multi-stage chamber assembled from these circles of partitions, which, when assembled into one system, will form a coil. Along it, pyrolysis gases will rise from the firebox to the chimney. Here they will be enriched with oxygen and burned completely. Be sure to make several small holes with a diameter of 3-5 mm in the wall of the cylinder opposite the first floor of the afterburning chamber. Holes are made with a drill and drill. The end of the created afterburning chamber channel is connected to the outlet pipe, which will become the beginning of the chimney. Therefore, a hole is made on the side or top of the cylinder for the pipe, and it is welded on the outside. As in any furnace, a firebox must be formed in a pyrolysis oven. To do this, a rectangular hole is made in the cylinder for the door. Fuel will be loaded through it. A grate is installed just below the hole, which can be made from the same metal sheet in which the holes must be drilled. You can make it from reinforcement in the form of a mesh. Below the door, on the same side where it will be installed, you need to make several holes to supply primary air.

This design makes it possible to ignite from above the fuel. Air will penetrate through the mass of stacked fuel briquettes and enter the smoldering zone. There will not be very much of it, which will prevent the fuel from igniting at full strength. By the way, sawdust, finely chopped stems or leaves, preferably pressed, fine coal, can be used as fuel in pyrolysis furnaces. Today, manufacturers of pyrolysis boilers offer their own fuel for them, which is made from any plant materials. They are pressed into small granules called pellets.

Pyrolysis stove made from a gas cylinder with a press

A simpler design of a pyrolysis-type stove can be made from a gas cylinder.

• The upper semicircular cap of the cylinder is cut off.
• Part of the sidewall is cut off for the hole for the firebox.
• The grate is installed.
• A pancake with a diameter slightly smaller than the inner diameter of the cylinder is cut out of a metal sheet.
• A hole is made in the pancake for the chimney pipe, which is welded to it.
• This structure must be made heavier, for which four pieces of channel are welded on its lower side. In this case, the chimney opening should not be closed.
• A hole for the chimney is also made in the cut-out cylinder cap.
• The door is hung.
• Small holes are made below the firebox.

Scheme of operation of a pyrolysis furnace from a gas cylinder

The oven is ready, you can load it. More than half of the resulting space is loaded. Ignition can be done from below or from above. A press made of a metal pancake reinforced with channels is installed on top. Its main task is to press the fuel to the combustion (smoldering) zone, while a space formed by channels remains between the walls of the press and the surface of the laid fuel. When burning fuel, the press will lower, leaving the gap the same during the entire process of operation of the pyrolysis furnace.

There is also a gap between the edges of the pancake and the walls of the cylinder, through which carbon monoxide enters the afterburning zone formed by the furnace lid and the upper plane of the press. Typically, such a unit is called a long-burning stove. As practice shows, one bookmark is enough for 6-10 hours, depending on the volume of the combustion chamber.

Lachinyan pyrolysis furnace

DIY pyrolysis oven

Those who own a country house, a bathhouse, a country house, or simply want to heat their home in a natural, inexpensive way will undoubtedly like a pyrolysis stove.

You say: “What, for example, is worse than a fireplace or a stone stove?”

Of course, stone stoves are very romantic and beautiful. However, in order to install such a structure in a house, you will need quite a lot of space, with a foundation prepared for it. Another disadvantage of fireplaces and heaters is that to maintain their combustion, you need to continuously add an impressive amount of kindling material.

Therefore, the most convenient option for accessible heat in a bathhouse or home is a pyrolysis oven.

Of course, such a stove has its advantages and some disadvantages, the latter, however, are quite insignificant.

Advantages of a pyrolysis oven.

1. Very economical fuel consumption. This is achieved due to the fact that such a stove operates not only on fuel, but also on gases released during its combustion. For this property, the pyrolysis furnace received a “second name” - a gas generator.
2. Almost any material can be used as fuel for the gas generator: from wood waste and old magazines, to recycled engine oil and plastic.
3. Minimum amount of soot produced. Due to the fact that the pyrolysis furnace processes the materials it has already processed several times, there is practically no residue left in the form of burnt fuel. This is a very environmentally friendly home heating solution.
4. High utility rate, up to 80%. Even if your entire house is heated by one steam generator, you can wear one T-shirt in all rooms, even in the most severe frosts.
5. Easy to control the oven system. Without a doubt, any household member can cope with the principle of controlling this equipment. Moreover, it does not require close attention; you just need to set the heating power and occasionally load fuel.
6. You don’t have to spend money on fuel or think about where to throw away household waste without harming the environment. Your waste is the fuel for the pyrolysis furnace.

Although this alternative type of heating has many advantages, of course, it is not without several disadvantages.

1. If you buy a ready-made boiler in specialized stores, it will cost you a pretty penny.
2. Fuel that is too wet cannot be used in any way for such a stove.
3. The gas generator must be permanently connected to the electrical network.

As you can see, in the lists we have given, pyrolysis furnaces still have more advantages than disadvantages.

Balloon oven options

There are several main options for such designs:

The simplest of them is an ordinary potbelly stove. It is customary to use a 12-liter or 27-liter cylinder for it. For efficient heating, it is advisable to use a horizontal elbow for the chimney. The most difficult part is attaching the door for the opening through which the fuel is loaded. Convenient for storage in a city apartment. It is short-lived due to the gradual burning out of the walls of the cylinder.

Special long stoves. They work as long-burning stoves. The basic principle of operation is that the fuel burns continuously with only a small amount of fuel. Pyrolysis products are then formed, which burn in a separate combustion chamber. To ensure combustion efficiency, it makes sense to preheat the air that enters the furnace. The oil garage stove requires vertical installation. Used engine oil is used as fuel. Adjusting the combustion temperature The design looks something like this.

"Rocket". Its name comes from the fact that it sometimes makes a noise similar to the roar of rocket engines. However, this can happen if the oven is not adjusted. A properly functioning structure makes only a quiet rustling sound. Its design is not particularly complicated and a 50 liter gas cylinder is very convenient for its manufacture. This type has many important advantages. They heat the room well, are economical to use, and relatively simple to manufacture. They can be adapted to heat a bed. But, on the other hand, they must be done accurately and carefully. If the furnace is poorly adjusted, it will be ineffective. The fuel is firewood (usually thinly chopped chips or branches). It comes through a pipe from above. Air enters through the hole at the bottom left. Combustion occurs in the lower pipe. The blowing here is very strong. The combustion products rise upward and exit through the pipe on the right, heating the room. Let us tell you what a stove called “bubafonya” is. It uses a special principle of working with pyrolysis products. The combustion chamber is located vertically. Pyrolysis products are contained by a special metal “pancake”, which limits the combustion space from above. The efficiency of this design can reach eighty-five percent. This stove is not designed to use wet fuel. Humidity should not exceed 12 percent. The stove is very economical in fuel consumption. Convenient to use for heating garages or other utility rooms.

A rocket stove can be made not only using gas cylinders, but also using barrels, cans and other means.

How to make a low-power pyrolysis oven?

The drawing of the pyrolysis furnace is quite approximate

Despite the relative complexity of the design of pyrolysis furnaces, you can make such a heating device yourself. Options for making the unit from brick or from a gas cylinder are quite common, but the most aesthetically pleasing and efficient in operation is a design made from sheet metal.

Pyrolysis furnaces with low power (up to 25 kW) are excellent for country houses, garages, greenhouses and any premises not exceeding 100 m2 in area. This design differs from a conventional pyrolysis furnace in the following features:

1. Does not connect to the heating system.
2. There is no need to install a smoke exhauster, since in this case the combustion chamber is simply located above the gasification chamber. This creates natural traction.
3. Due to the fact that the design is not automated, it is necessary to periodically adjust the combustion mode and monitor the operation of the equipment.

Construction of a low-power pyrolysis boiler

The instructions for making such a stove include several steps:

1. According to the diagram, the structure body is welded from heat-resistant steel, in which holes are provided for the ash pan door and the combustion chamber. In this case, the combustion chamber should be located above the ash pan, separated from it by a cast-iron grate.

1. The gas combustion chamber is located exactly above the firebox. Between them there is a cut-off plate, which is made of heat-resistant steel. The firebox must have a special channel through which air will be supplied with the possibility of shutting it off using a special damper.
2. The same sheet metal is used to make the doors, which is additionally reinforced with a corner. Doors must be locked.

1. The inside of the furnace chamber should be lined with fireclay bricks, which will not only protect the structure from burning out, but will also contribute to better heat distribution.

1. The chimney should be made of a heat-insulated pipe. To regulate the draft in the design, a gate is provided.

Testing a homemade pyrolysis boiler

conclusions

Having considered how to make different types of pyrolysis furnaces, we can summarize that it is realistic to make only a structure from a gas cylinder. You won’t be able to build a brick oven yourself; it’s too difficult. A camping option made from cans also has a right to exist, but it can only be made at home; this cannot be done in the field. And finally, the exhaust furnace is simple but dangerous and requires very careful and careful operation. The risk is quite high, so we do not recommend it for heating a garage.

Drawings, dimensions and calculations

You can make a small stove with your own hands to heat a garage or other space using scrap materials.

It’s easy to create a sketch plan and drawing of a small metal stove-stove yourself

An obligatory step is the creation of a drawing or diagram of the future structure. To do this, you need to determine the shape and dimensions of the case, the location of the cameras. After this, the power sufficient to heat the room is calculated. The parameters are determined as follows:

• Let's assume that 10 kW of heat is required to heat the room at the lowest outside temperature. We determine the required power of the furnace in normal combustion mode. It is known that in the gas generation mode the furnace power is 10-30% of that which develops in the flame combustion mode. Consequently, to obtain 10 kW with gas generation, the unit, when burning with a flame, must develop a power of W = 10 / 0.3 = 33.3 kW (we assume a 30 percent power ratio);
• We choose the least energy-intensive fuel. For example, dry beech is optimal;
• We calculate the volume of fuel that can provide the required power. A portion of firewood burns in flame mode in approximately 4500 s. Therefore, during this time it should provide the following amount of heat: Q = 33.3*1000*4500 = 149.85 MJ. Let's calculate the required mass of fuel, taking into account that it burns only 80% completely, and the efficiency of a homemade stove is approximately 50%: M = 149.85 / (15.5*0.8*0.5) = 24.17 kg. Knowing that the density of dry beech is 620 kg/m3, let’s convert the resulting mass value into volume: V = 24.17 / 620 = 0.039 m3 = 39 l;
• We calculate the volume of the firebox. The average furnace load factor is 0.63. It should have a volume: Vt = 39/0.63 = 61.9 l.

You can make a drawing or technical drawing of the product yourself, taking into account the shape and features of the stove. A ready-made image of a suitable unit is taken as a basis.

Tools and materials

List of required consumables and working tools:

• sheet steel grade St20, thickness 3–4 mm;
• steel equal angle angle 4x50 mm;
• pipe with a diameter of 50–60 mm;
• steel reinforcement with a cross section of 8 mm;
• steel pipes with a diameter of 110 or 120 mm for the chimney;
• bricks in the amount of 15 pieces;
• electric welding machine and several packages of electrodes;
• drill and metal drills, grinder with 230 mm circles;
• building level, tape measure, pencil, hammer.

Choose consumables that are high-quality and reliable. Not only the operation of the pyrolysis furnace, but also the safety of the surrounding area during the heating process depends on this.

Preparation and selection of installation site

The assembly of the structure is carried out directly in the room where the stove will be installed. It is best to order sheet cutting into blanks from specialists in the store. This will ensure a good quality base for the product.

The space around any stove must be safe and heat-resistant, and the floors must be level.

The site for installing the unit must be prepared.

• a base of bricks or other non-combustible material is laid on the floor;
• the base area should be larger than the dimensions of the oven;
• install the unit at a distance of at least 80 cm from the nearest walls;
• the floor within a radius of 1.2 m in front of the heating device must have a fireproof coating (iron sheet 1.5 mm thick).

Rectangular stove with reflector

When deciding what shape and size a finished potbelly stove should take, everyone must do it on their own. A person with an engineering education and skills can take any, even the simplest design, and make the desired changes to it to improve it.

Drawing of a rectangular potbelly stove:

A simple and multifunctional do-it-yourself potbelly stove is made from the following materials:

• Sketches and simple drawing of the structure indicating all the main dimensions
• Sheet metal (its quantity depends on the desired dimensions of the furnace)
• Steel corners (thickness 4-5 mm)
• Metal tube 25-30 mm
• Pipe 180 mm
• Welding machine
• Working hand and electric tools

The furnace body will be made in the form of a rectangle using steel sheets, which are butt welded together. It is necessary to cut the workpieces into five main planes (bottom, top, side and back walls). On the front panel there will be a blower and a door for the furnace, so the issue can be resolved with it later.

First, the side surfaces are welded to the bottom. It is necessary to ensure that they are positioned strictly vertically, using a level or square, and are joined at right angles. Having grabbed it in 2-3 places, we once again make sure that their location is correct and finish cooking.

Afterwards the back wall is welded. The entire internal space must be divided into three parts:

1. Smoke circulation
2. Firebox
3. Ash pan

The last two must be separated by a grate on which solid fuel (peat, firewood) will be placed. It is done as follows:

1. From the inside on the sides at a certain height (10-15 cm), corners are welded over the entire length
2. For the grate, it is necessary to prepare strips of thick sheet steel with a width of 25-30 mm and a length corresponding to the width of the potbelly stove

• The distance between the plates is about 5 cm
• The strips are welded to two metal rods with a diameter of 15-20 mm as reliably as possible, since they have to perform another role - stiffeners

There is no need to weld the grille to the inner corners. If necessary (cleaning the potbelly stove, repairs), it can be easily obtained. After some time, some plates may burn out and will need to be replaced. There are many more reasons to leave the grille removable.

The next step is to weld two metal rods on top on which the reflector will be located. The latter is a metal sheet that separates the smoke circulation and the firebox. The reflector is made removable.

It is necessary to position the reflector so that a channel is formed in front, allowing smoke to escape. It will heat up inside the most, so it is made of very thick metal (12-16 mm).

The time has come to begin the final stages of work. First, the future potbelly stove lid is welded. It would be a good idea to provide a hole for the chimney pipe in advance. Then the upper jumper is cut out and welded, then a narrower one, placed at the level of the grate and separating the doors of the grate and the ash pan.

There is no need to worry too much about the size of the doors. The main thing is that it is convenient to lay firewood through them and remove ashes and ash. The door for the firebox is made, as a rule, almost the entire width so that the reflector and grate can be removed; for the ash pan it is narrower.

Next, you need to weld the handles for the potbelly stove doors, latches and curtains. It is recommended to make the latter yourself from a thick rod and a steel tube. Such work should not be difficult.

Having put everything together, it’s time to think about installing the finished structure on the legs. It is recommended to make them from a metal tube 2-3 cm in diameter and 8-10 cm in length with a nut welded at the end and a bolt screwed in. This will allow you to adjust the height. This step may seem strange to many, but during the installation process everything will become clear.

A rotating damper must be provided at the lower end of the chimney. For it, a circle is cut out of sheet metal, with a diameter slightly smaller than the same characteristic of the pipe, in which a hole is drilled for the handle for rotation. The latter can be made from a metal rod.

The chimney pipe must be placed on a sleeve 15-20 cm high. It is made from a product with a diameter slightly smaller than the chimney pipe and is welded along the hole to the top cover. It's time to install the stove, adjust the height and that's it - you can heat the room.

Self-assembly options

Pyrolysis furnace made from a metal barrel

Homemade structures can be made from various materials, such as a gas cylinder, tin cans, barrels, bricks and much more.

Depending on the material of production, all furnaces are divided into:

• stone;
• metal.

Stone or brick ovens are used extremely rarely. This is due to the fact that its construction will require a lot of investment and time.

Of course, recently such designs have undergone some modifications, which has significantly increased their efficiency. As for metal stoves, they are especially popular. The fact is that they can be made even from an old gas cylinder or barrel.

Pyrolysis furnace Lachinyanka

Depending on the principle of operation, the fuel and material used, all furnaces are divided into the following types:

• furnace operating on treated oil;
• Kuznetsov furnace;
• Lachinyanka;
• Buleryan stove;
• Bubafonya.

The principle of operation of all these structures is the same - afterburning the gas that is released from the fuel. But, when choosing a design, it is worth considering some features of each type.

Thus, it is undesirable to use stoves that run on waste oil in bathhouses and other residential premises. They are ideal for heating garages and other non-residential premises.

Of course, it is worth considering that small furnaces running on waste oil are highly productive. You only need a cup of oil to get the job done.

You might be interested in an article on how to make a pyrolysis boiler with your own hands.

Read a review of modern models of pyrolysis boilers for heating here.

Made of brick

To build a brick stove you will need:

Drawing of a pyrolysis furnace. (Click to enlarge)

ceramic and fireclay bricks; steel sheets; cast iron grates; 300 W fan; door to the furnace room and for the blower; welding machine; drill; Bulgarian and others.

Having such materials and tools at hand, you can build a stove with your own hands. Of course, we should not forget about some nuances on which the strength and efficiency of the heating structure will depend.

If you have chosen a brick kiln, the construction process will look like this:

1. Clearing the site and installing the foundation. The best option would be a strip foundation. It must have high strength.
2. After the foundation has hardened, you can begin laying bricks. For this purpose, high-quality refractory bricks are used, which are highly durable.
3. The inside of the oven is lined with fireclay bricks, which can withstand high temperatures.
4. Chimney installation. It is best to use metal inserts or ceramic structures here.

Keep in mind: the installation of a chimney must be approached with great responsibility and it is better to consult with a stove professional in advance.

All work is carried out according to a pre-drawn plan, which is best agreed upon with a specialist.

If necessary, you can decorate the structure. For this, facing bricks, stone and other materials that can withstand high temperatures are often used.

From a gas cylinder

The peculiarity of the Bubafonya stove is that it can be used with different fuels.

To make such a design with your own hands, you will need the following tools:

• hammer;
• Bulgarian;
• welding machine and electrodes;
• pliers.

The manufacturing process of the Bubafonya stove is carried out in the following sequence:

1. Cut off the top convex part of the cylinder.

Be careful: cut off the top of the cylinder below or above the welding seam, since the connecting seam is reinforced from the inside with a metal plate, which can complicate cutting.

There is a hole in the center for the air duct. At the top of the cylinder body, a hole is made for the chimney. Make a gas divider with a pipe through which oxygen will be supplied to the second chamber. Weld the chimney.

As you can see, you can easily make a stove from a gas cylinder with your own hands

But you should pay special attention to cutting the cylinder. Before you start working with an angle grinder, you need to make sure that there are no gas residues in the cylinder; to do this, fill the cylinder completely with water

Heat exchanger for wood boiler

Heat exchangers are quite often considered the “heart” of a solid fuel boiler. It takes heat from the flue gases through the walls of the heater and releases it to the coolant circulating inside the housing.

Heat exchangers can be made of cast iron or steel, the former is more expensive and has high thermal efficiency, operating time and endurance.

Such a device is large-sized and has a certain inertness both during heating and during cooling. Cast iron units are unpretentious and exhibit anti-corrosion resistance. With proper operation, the device can operate trouble-free for about 30 years.

Steel heat exchangers are made of pipes and sheet steel up to 6 mm thick. They are designed for open heating systems operating with natural coolant circulation, are susceptible to corrosion and can operate for no more than 15 years.

Homemade pyrolysis oven from a gas cylinder

Design and operating principle of a gas cylinder stove.

You can make a pyrolysis oven with your own hands according to the drawing from an ordinary gas cylinder; it is also called the Bubafonya oven. Pyrolysis is the separation of organics from inorganics in the absence or deficiency of oxygen. During pyrolysis combustion, temperatures up to 500 degrees are reached. This is a necessary condition for the released pyrolysis gases from wood to burn out.

A pyrolysis furnace from a gas cylinder can operate on any solid fuel, and the fuel moisture level can reach 70%. The cylinders are made of ferrous metal, 3–4 mm thick. The upper part is made in the form of a dome and welded to a cylindrical base. Let's consider what manipulations need to be carried out to make a pyrolysis oven from a gas cylinder:

• cut off the upper convex part;
• in its central part we make a hole for the air duct;
• in the upper part of the conical body we make a hole for the smoke exhaust;
• we manufacture a gas divider with a pipe for supplying oxygen;
• We weld the chimney.

In principle, a homemade pyrolysis oven from a cylinder has a fairly simple design. In your work you may encounter various nuances.

Gas diffuser at the end of the air supply pipe.

The hole in the lid should almost coincide with the diameter of the air supply pipe, and the latter should move easily. The diameter of the gas divider must also be matched to the size of the tank. At the bottom of the gas divider, ribs are welded to direct gas flows. It is better to make them curved so that the flow swirls. Remember, the fewer extra gaps, the higher the efficiency of the unit.

To protect yourself, before starting cutting, you need to fill the cylinder to the top with water, in case gas vapor remains inside. Even if there was liquid in the cylinder before, and there are definitely no gas vapors, a characteristic smell of propane may appear during cutting. Don't worry, it's the additives that are added to the gas that smell. They tend to settle on the inner walls. Additives are a necessary warning measure, since the gas itself has no odor.

The operating principle of a homemade pyrolysis oven from a cylinder:

• Fuel is placed in a cylindrical tank and ignited;
• a pipe with a gas divider at the end is installed on top (the latter should press the fuel);
• the lid is put on top;
• combustion occurs from top to bottom; as the fuel burns out, the pipe with the gas divider lowers.

A feature of this fuel combustion method is the minimum amount of smoke and soot. There is really very little ash. After the first burning, a sharp smell will appear - this is the burning paint that covers the cylinder. There is no point in removing it mechanically, as it is ineffective. It’s easier to burn out everything unnecessary by testing kindling.

To make long-burning pyrolysis stoves with your own hands, you will need the following equipment:

• Bulgarian;
• hammer;
• pliers or pliers;
• welding machine.

To carefully cut a round hole with a grinder in a blank for a pyrolysis oven from a gas cylinder with your own hands, you need to take a small, already erased circle and make a 1 mm indentation along the cutting line. Then, using a large, new circle, cut a square in the center of the marked hole and make slits from it to the edges with an indentation of 1–2 cm, like the petals of a flower. Then the petals are bent inward with a hammer. The bend line will run exactly along the intended perimeter with a depth of 1 mm. The petals can then be broken off with pliers.

As a result, we get a neat hole. If you immediately use a large circle, then the cuts will inevitably go beyond the boundaries of the markings. After this they will need to be brewed. As you know, no welding seam can compare in strength to solid metal.

Types of long-burning stoves

Options for furnaces of this type are classified depending on the material, method of operation and method of heat transfer. The designs differ in the type of traction and the relative position of the internal chambers. Thus, stoves are made of metal or brick.

Table: classification of pyrolysis furnaces

Photo gallery: variety of heating units

Based on the method of heat transfer, the units are divided into models:

• with a water heating circuit;
• variability in the placement of heat exchangers (combustion and smoldering chambers are located in different orders). If the firebox is located at the top and the afterburning chamber is at the bottom, then forced draft is required using smoke exhausters and fans. If, on the contrary, the firebox is located below, then natural draft is triggered.

How to choose a stove option

First decide:

• for what purposes is the stove needed;
• where will she stand;
• what fuel to run on?

When choosing the type of structure to DIY, consider the area and type of space. Depending on the parameters of the heated room, the size and power of the furnace are selected. It is worth considering that brick models are placed in a permanent place for future use, while metal ones are almost all mobile.

A homemade stove must meet the necessary characteristics and be safe to use

When making any furnace model, it is worth calculating the balance between the ratio of oxygen and gas. Therefore, the selection and assembly of any furnace option requires careful calculation of the parameters, power and dimensions of the product.

Structural elements

High-quality steel sheets are used to create rectangular metal structures. In this case, the stove is made with double walls. The space between them is filled with sand or water (water circuit). Metal barrels with thick walls can serve as the basis for making a small oven.

The metal structure can be covered with bricks from the outside (lining) or from the inside of the furnace (lining)

The pyrolysis furnace has two combustion chambers. In one compartment, solid fuel is processed, and in the other, pyrolysis products are mixed with air. When the firebox is located at the top for solid fuel, a grate is placed between the compartments. In metal furnaces, the partitions are hollow plates inside.

A visual representation of air flows during operation of a pyrolysis stove with a firebox in the lower compartment

Charge fans are necessary elements in structures where the gas chamber is located below. With the help of forced draft, gaseous substances move downwards, where the afterburning process begins. Such products also contain smoke exhausters on the exhaust channels.

Forced draft directs the gases to the second part of the furnace, where they are burned (releasing a large amount of heat)

All structural elements are interconnected, ensuring efficient operation of the pyrolysis furnace.

Features of operation and rules of safety regulations

It is very easy to operate such a sauna stove:

• collected thick and long firewood;
• they filled the entire volume of the firebox;
• They opened the damper and ash pan, made sure there was good draft and lit the wood.

Everything, as the wood burns, the stones heat up, the water heats up. You can call your friends, take brooms and a supply of herbal decoction or just kvass and, after throwing a few shakes on the stones, enjoy the fragrant and hot steam and conversation with loved ones.

When operating, it is important to follow the rules for safe use of the oven. There are few of them and they are very simple:

• Be sure to monitor the condition of the chimney. At the first sign of its malfunction or decrease in traction, all problems will need to be corrected immediately. It is recommended to clean the chimney at least once a month;
• after the wood starts burning, the ash pan door must be closed;
• The firebox door opens only to add firewood and control its combustion. The rest of the time, when the fuel is burning, the door must be securely locked;
• You should not try to heat the oven by touching the sides with your bare hands - this will lead to burns on your hands. The level of heating can be felt by the amount of steam from the stones when water is splashed on them from a ladle.

A little more about the chimney

It is worth noting here that thanks to the design of the stove, which consists of two sections, a chimney pipe that is too long will not “steal” heat - an increase in draft will only contribute to increased combustion and an increase in temperature. The main thing is to secure it so that the wind does not uproot it. But it’s worth thinking about the deflector (protective cap). If there is snow or a blizzard at night, the pipe may become completely clogged. In this case, lighting a potbelly stove will be quite problematic. In the photo below you can see that I raised the chimney quite high. However, when this photo was taken, the deflector had not yet been installed.

This is the chimney pipe I got