DIY rocket stove making. Do-it-yourself rocket stove made of long-burning bricks. Gas cylinder unit

The rocket stove is widely known throughout the world as a long-burning heating design using solid fuel. In order to achieve maximum efficiency I had to work hard. A liquid fuel stove can release all its energy, but wood is more difficult to process. To unlock the full potential of wood, jet kilns were equipped with a chamber for afterburning gases.

The Shirokov-Khramtsov rocket or jet stove did not get its name because of its connection with space. The point is the shape of the device and the noise that is created during operation, reminiscent of the operation of a rocket. But this sound indicates improper use of the oven.

Types of long-burning rocket stoves:

• Portable (mobile);
• Stationary (for heating).

The most popular rocket model is Robinson. It is often used on hikes. Thanks to a small portable device, you can understand the principle of operation of jet furnaces. The shape of the oven resembles the letter “L”.

If the furnace is too noisy and buzzes during operation, then this mode is ineffective and expensive. Normally there should be a quiet sound, a little rustling.

The reaction furnace has a receiving hopper. This is the horizontal part of the pipe. A draft arises in the channel itself, it is this that affects the intensity of combustion, warming up the body. This is why it is advisable to limit the oxygen supply. Otherwise, the wood will quickly burn and all the heat will disappear.

The stove operates on jet traction due to the natural flow of hot air. The higher the temperature of the firebox walls, the better the wood burns. This allows you to quickly heat water in large capacity, which is indispensable on a road trip. If you equip the pipe with thermal insulation, then after warming up you can burn thick logs.

DIY rocket stove: advantages, drawings, disadvantages

If desired, the conventional design of the furnace can be improved. This is how the potbelly stove loses a lot of heat, but by equipping the device with a water circuit or brickwork, these problems can be solved. Drawings are made for all these manipulations.

Advantages of jet furnaces:

1. Simple and inexpensive design. You can use available materials without significant financial costs. All work can be done with your own hands; no special knowledge or skills are required.
2. You can control the combustion yourself by choosing the desired intensity.
3. High efficiency. In general, everything depends on the quality of installation. The main thing is to extract maximum energy from the flue gases.

But such a simple and convenient design also has significant disadvantages. So you need to select special fuel for the stove. You cannot use wet firewood, otherwise pyrolysis will not occur. The firebox may begin to smoke profusely, and all the gases will be directed into the house. In addition, a rocket stove requires increased safety requirements.

The most popular portable model is the Robinson rocket stove. It was modified and a grate was added.

Homemade jet stoves are not used for heating baths. They are ineffective in infrared light, which plays an important role for a steam room. Surface structures have a small heating area, so they cannot heat the bathhouse.

Drawings of a jet stove from a gas cylinder and other types

Long-burning stoves are divided into stationary and mobile. Mobile stoves are used on hikes, picnics, and outdoors for heating and cooking food. Stationary ones are used for heating a house, outbuildings, greenhouses, and garages. There are 4 types of structures.

Types of reactive furnaces:

• Homemade camp stove from metal pipes, buckets, cans;
• Jet design from a gas cylinder;
• Brick oven with metal container;
• Stove with a stove bench.

The portable structure is equipped with pipe sections. The only difference concerns the installed partition for the ash pan. For the lower part, a grate can be used.

A device made from a gas cylinder is more difficult to build, but significantly increases efficiency. To install the structure you need a barrel or gas cylinder. Firewood in the firebox burns due to the influx of oxygen by loading it through a special window.

The gases burn out in the pipe, which is located inside the structure, due to the supply of secondary air. The effect is enhanced by insulating the inner chamber. Hot air is placed in the hood, and then into the outer chamber. Combustion products are removed through the chimney.

To create draft, the top of the chimney is placed 4 cm above the loading window.

The combined model made of brick and metal is a stationary structure. Due to its high heat capacity, a wood stove accumulates and releases heat over several hours. That is why residential premises are heated with this design.

The rocket unit with a bench is an improved device that can retain heat longer. Since some of the heat escapes through the chimney, we increased its length. Due to the rapid excision of hot gases and a larger smoke outlet, this problem was solved.

This creates massive stoves with a bench that look like a sofa or bed. This stationary devices made of brick or stone. Thanks to its unique design, the stove is able to retain heat all night.

DIY drawings of the Flint stove and other models

It is best to make small portable structures with your own hands: the “Ognivo” and “Robinson” rockets. It is easy to perform the calculation, and the work will require cutting of profile pipes and metal welding skills. Dimensions may differ from the drawing, that's okay. It is important to maintain proportions.

To increase the combustion intensity, it is recommended to add improvised nozzles to the design. Secondary air for afterburning will flow there.

Stationary rocket stoves are made from a gas cylinder or metal barrel. These elements act as a body. Inside, the stove is equipped with smaller pipes or fireclay bricks. From a cylinder you can make both a stationary unit and a mobile one.

Continuous combustion furnace diagram:

• Chimney;
• Cap;
• Insulation;
• Loading hopper;
• Combustion zone;
• Afterburning zone.

Calculating a rocket stove can be difficult, because there is no exact method. You should pay attention to proven finished drawings. It is necessary to determine the size of heating equipment for a specific room.

DIY jet stove assembly for heating

Construction of the furnace begins with preparatory work. First you need to decide on the place of construction. It is chosen based on the requirements that relate to solid fuel structures: wood or coal.

Once the location has been decided, it is necessary to properly prepare it for construction. The wooden floor under the stove is being dismantled. They dig a small pit and compact the bottom.

In a small room, the jet stove is placed in the corner. The loading hopper occupies one side and the deck chair occupies the other.

The barrel or cylinder also needs to be prepared for installation. To do this, cut off the lid and tap. Then the structure is cleaned. Next, prepare the solution.

Stages of construction of a jet stove with a stove bench:

1. The bottom of the dug hole is lined with fireclay bricks. Formwork is made along the contour of the recess. Reinforcement is performed.
2. Lay out the base and fill it with concrete. A day later, when the concrete has hardened, further work begins.
3. The base of the stove is made of fireclay bricks. The side walls are raised and a lower channel is made.
4. The combustion chamber is covered with brick. There are two holes left on the sides. One is intended for the firebox, the second is for the vertical pipe (riser).
5. The metal body is equipped with a flange into which the horizontal channel of the stove will flow. All seams must be airtight and well sealed.
6. A side outlet is attached to the horizontal pipe, which serves as an ash pan.
7. A fire tube is made from brick. As a rule, it is square.
8. The flame tube is equipped with a casing. The gaps are filled with perlite.
9. The installation of the cap is done from a cut-off part of a barrel or cylinder. It is equipped with a handle.
10. Equip the furnace body with brick or stone.
11. Equip the front part of the stove. Lay out the required contour.
12. A prepared barrel is placed on the base. The lower part must be sealed with clay.
13. Using a corrugated pipe, a channel is formed connecting the firebox to the street.
14. The heat exchanger pipes are connected to the lower pipe.
15. Installing a chimney. All elements must be sealed using asbestos cord and fire-resistant coating.

Improved rocket furnace with water circuit

A long-burning boiler can be obtained by equipping the stove with a water jacket. Water heating may not be efficient enough. The fact is that the bulk of the warm air enters the room and containers on the cooking surfaces. To create a rocket boiler, you need to give up the possibility of cooking on the stove.

Materials required for equipping a stove with a water circuit:

1. Fireclay bricks and mortar for masonry;
2. Steel pipe (diameter 7 cm);
3. Barrel or cylinder;
4. Insulation;
5. Sheet steel and a barrel of smaller diameter than for the body to create a water jacket;
6. Chimney (diameter 10 cm);
7. Parts for the heat accumulator (tank, pipes, connecting pipe).

A characteristic feature of rocket furnaces with a water circuit is that the vertical part is insulated to ensure combustion of pyrolysis gases. In this case, warm air is directed into a coil with a water circuit and transfers heat to the stove. Even when all the fuel has burned out, warm air will still be supplied to the heating circuit.

DIY rocket stove drawings (video)

Jet stoves are widely known among people. Even Korea, China, England and the population of Japan used them. The Chinese stove differed from others in its ability to heat the entire floor. But the Russian analogue is in no way inferior. Thanks to useful innovations, the stove can hold heat for a long time.

Examples of a rocket stove (photo of ideas)

A simple heating device, which is not much inferior in popularity to a potbelly stove, is a rocket stove. It runs on wood, and the design is so simple that production is possible on your own. The stove can also be made economical - many people think that looking like a potbelly stove means the combustion chamber is gluttonous, but no. There are schemes that operate on smoldering wood (pyrolysis), which means they are economical with the same efficiency.

Why rocket and why jet

Such a stove is often called a “rocket”, but not because the wood in it burns at a high speed, but because of the shape of the structure - the traditional version of the rocket stove is made from two sections of iron pipes welded to each other. The unit resembles a rocket in a child's drawing. Using a simplified form allows you to make it in less than a day. The adjective “reactive” is also applied to the stove, but also not because of the rate of fuel combustion, but because of the combustion characteristics - at a certain stage of supplying air to the firebox, it begins to hum strongly, as if the turbocharging of the injectors in the engine is turned on.

A humming stove is an inefficient and wasteful combustion mode. During normal operation, it makes a quiet rustling sound.

Any owner of a country or country house has at least a minimum set of carpentry, plumbing and automotive repair tools in his workshop. These are the ones that will help in the manufacture of a miracle rocket, plus drawings and a minimum supply of materials: pipes or metal boxes, a sheet of iron and - when building a stationary version - brick and mortar on clay. Now it becomes clear that the jet stove is made portable or stationary, for example, for heating a house or bathhouse.

If a stationary jet stove will heat the house, then it is placed along the outer wall. Properly designed and equipped, it can heat a house with an area of ​​up to 50m2. The stove is also installed in an open area - on a personal plot, and is used as a summer option for cooking.

How does a rocket stove work?

The device is the simplest - two principles of fuel combustion, borrowed from other stoves:

1. Natural circulation of hot gases and smoke through the stove channels is a standard solution, as in a potbelly stove.
2. Afterburning of unburned gases (pyrolysis) with limited access of oxygen to the combustion chamber.

The design of the simplest reactive stove, which is intended only for cooking, uses precisely the natural combustion of wood - in an open chamber it is impossible to create conditions for maintaining the pyrolysis reaction and the afterburning of unburned gases.

Let's consider a simple design of a direct combustion rocket stove, which is traditionally installed in an open area in the yard. You can quickly heat water on it or prepare lunch for your family on vacation. From the figure below it becomes clear that such a sample will require two sections of a cylindrical or rectangular iron pipe, which are connected to each other by welding at an angle of 90 0.

A horizontal section of a metal box acts as a combustion chamber; firewood is placed there. You can also organize fuel loading vertically - add a vertical iron cylinder on top of the horizontal pipe to load firewood. Thus, you will get a structure of three pipes or boxes, the lowest of which (horizontal) will work as a firebox. In a stationary scheme, the simplest stove design often uses red brick, which is placed on a clay mortar.

The efficiency of the design cannot be called satisfactory, so the craftsmen figured out how to increase its efficiency. The additional element is another pipe of larger diameter (as you can see, all materials are available and cheap), into which the main pipe of the riser stove (primary chimney) is installed. This increases the overall heating and the duration of heat retention.

On the diagram:

1. Outer casing.
2. A pipe that serves as a firebox.
3. A channel for air outlet into the combustion chamber.
4. Insulated area between the body and the riser. The same ash can serve as insulation.

How to heat

The Robinson jet stove is heated according to the principle of starting a fire - paper, hay, straw or other flammable material is laid first, then small chips or large shavings. The last logs to be placed are the size of the firebox. Hot combustion products rise through the vertical pipe (2) and exit outside. You can place a pan or tank of water on the open end of the pipe (2).

In order for the fuel to burn continuously and actively, it is necessary to provide a gap between the outlet pipe (2) and the pan of water using a special lattice metal stand.

The diagram below shows a simple device with a door on the opening for loading fuel. Air draft is formed due to the presence of a special channel formed by the lower surface of the firebox and an iron plate welded 8-10 mm from the combustion chamber. This design will force air to be pumped in even if the door is completely closed. It is clear from the diagram that the design is also designed to operate in pyrolysis mode, while a constant flow of a “secondary” air stream will burn the exhaust gases. But in order for afterburning to take place 100%, it is necessary to arrange thermal insulation of the secondary chamber in which the gas burns out in order to provide the necessary temperature indicators for pyrolysis.

On the diagram:

1. Forced channel for blowing air when the combustion door is closed.
2. Active combustion area.
3. Burnt gases.

The improved scheme provides not only the possibility of heating the surrounding space, but also cooking food, for which the upper hob is designed. Total: to the simplest version of the “rocket” you can add an outer casing, which will additionally heat the room, a combustion door, air supply to maintain the pyrolysis mode, and a stove for cooking food. This scheme can already be implemented in the house itself, and not in the yard, since the chimney pipe is led outside. This minor upgrade significantly increases the efficiency of the model. Thus, a do-it-yourself rocket stove, the drawings of which are presented below, has the following capabilities:

1. Due to the inclusion of an outer casing made of a larger diameter pipe and its insulation, which creates a thermal insulation layer for the riser, as well as the ability to hermetically close the upper pipe, hot air cools down much longer.
2. A separate channel for blowing has been added to the lower section of the stove, which makes it possible to organize pyrolysis combustion.
3. In this design, it is recommended to place the chimney not vertically at the top, but at the bottom at the back of the body, which will allow for additional circulation of hot flows through the internal channels of the stove, ensuring quick heating hob and the entire insulated body.

In the firebox (1), the fuel does not burn completely (2), since the air supply is not complete - this is mode “A”, which can be controlled using the damper (3). Gases that are hot, but not burned out from pyrolysis, are supplied to the end section of the fire channel (5), in which they are burned. Afterburning is ensured by high-quality thermal insulation and a constant flow of “secondary” air in mode “B” through channel (4).

The hot stream then enters the internal riser (7), rises up to the cooking plate (10) and heats it. Next, hot air enters the volume (6) between the outer and inner pipes, insulated with a layer of ash (4, 9), heats the furnace body, which releases heat into the room. Finally, the cooled air falls down to enter the chimney (11) and exit out.

A consistently high temperature in the riser (7) ensures maximum heat transfer and creates conditions for complete combustion of gases by placing the riser in a larger pipe - the shell (8). The free space is filled with ash or other heat-resistant substance (9) for lining - this can also be a solution of ordinary clay and sand in proportions 1:3.

The palm of popularity belongs to the industrial model “Robinson” - it is a simple but reliable design. Having such a mobile stove, you can quickly cook food or heat water at the dacha or on a hike. Structurally, it is an inverted L-shaped pipe, as shown in the diagrams below.

Firewood is placed in the horizontal section of the fuel receiver, and ignition is carried out from the side where the vertical pipe enters. In an L-shaped pipe, due to the difference in pressure of hot and cold air, draft arises, and the intensity of combustion will only increase as the furnace body heats up. The air supply is regulated by a slide damper.

The furnace operates on the principle of using the energy of a natural flow of hot gases. It turns out to be a closed cycle: as the temperature rises, the fuel begins to burn more actively and the chamber and cooking surface heat up faster. As a result, Robinson is able to heat 10 liters of water in 10 minutes if you place the tank on an already warm surface. The diagram shows that the hob in Robinson has a thick thermal insulation layer, which allows you to put large diameter logs into the firebox.

Stationary oven

Stationary models have a hood to keep the heat in the room longer. In such a stove, fuel combustion occurs according to a different scenario. The beginning of the wood combustion process is the same - the air supply is limited. This causes the release of pyrolysis gases, which are burned in the lower section of a vertical pipe or box, where secondary air is supplied separately.

The hot gas, once at the top, begins to cool and falls into the free inter-chamber volume, and then into the chimney. It happens like this:

1. Gravity forces force the colder, and therefore heavier, burnt gases to rush downward, where they enter the chimney.
2. This is facilitated by the constantly maintained pressure from the added firewood and the consistently high temperature of the gases.
3. Natural draft in the chimney pipe.

All this creates effective conditions for burning wood and it becomes possible to attach a smoke channel with arbitrary geometry to the “rocket”. Basically, long and complex chimneys are needed in order to better heat the room.

The main disadvantage of all solid fuel stoves is the inability to retain most of the heat in the house. But the positive qualities make it possible to neutralize the negative aspects - the high rate of gas escape allows you to organize complex vertical or horizontal chimneys with several channels. The implementation of this principle in practice is the Russian stove. In a jet stove with a horizontal multi-channel chimney, you can also equip a warm bench, as shown in the diagram below.

A rocket stove is a home heating option that can only be cheaper for nothing. A person familiar with the basics of construction can build a combined brick stove in a design suitable for any home interior. The main task of improving the appearance will be decorating the iron cap and firebox lid - everything else will not be in plain sight.

Combined brick-metal barrel stove

It is stationary, because the structure cannot be moved. The fuel chamber and chimney are made of fireclay bricks, and valves and doors are made of metal. Brick gives off heat very slowly, so the room will be warmed for a long time.

High efficiency is not the strong point of such models, but good heat transfer can be achieved by adjusting the air supply to the chamber, without trying to reach a combustion mode in which the stove begins to “roar” and “hum.”

In order to somehow minimize heat losses during operation of this simplest design, many craftsmen build a water circuit into the furnace and connect a reservoir for hot water. The construction of a bench with a multi-channel horizontal chimney also helps to preserve heat in the room. Negative qualities of “rocket” models that cannot be minimized or eliminated:

1. Constant monitoring and adjustment of traction is required - no automatic devices are provided.
2. Every 2-3 hours you need to load a new portion of firewood.
3. The iron cap heats up to dangerous temperatures.

The simplest and cheap option– model “Robinson”, which is in the drawing below. To make it, you need cuttings of pipes or a rectangular profile box, metal corners for the legs, and a welding machine. Its dimensions are selected based on the dimensions of the workpieces. The main thing is to adhere to the principle of action, not the size.

For homemade design They often take 200-liter gas cylinders or barrels - thick walls and the appropriate size are exactly what was intended. Both are used to make the outer casing, and the internal elements are made from pipes of smaller diameter or are laid out with bricks - halves, quarters or whole.

There is no general formula for calculating heat transfer for all models of a rocket stove, so the option of using ready-made calculations based on the principle of similarity of circuits is quite suitable. The main thing is that the size of the future “rocket” at least approximately corresponds to the volume of the heated room. For example, a gas cylinder will do for a garage, and a two-hundred-liter barrel will do for a country house. Approximate selection internal elements shown in the diagram below.

Iron cylinder stove

1. Cylinder – gas, oxygen, carbon dioxide.
2. Pipe ≥ 150 mm for fuel and loading chambers.
3. Pipes 70 and 150 mm - for internal vertical chimney.
4. Pipes 150 mm - for the outlet chimney.
5. Insulation of any type, always non-flammable.
6. Blanks sheet metal H = 3 mm.

The upper part of the cylinder is cut off by welding. For safety reasons, it is better to open the shut-off valve on it and fill it with water before cutting. On the sides you need to cut openings for the fuel chamber and chimney. The pipe under the firebox is connected to the vertical pipe of the chimney channel from the bottom of the cylinder.

After installing the internal elements, the cut top is welded back. The seams are checked visually and the main chimney is connected. If there is a water circuit, it is connected too. After this, the rocket stove can be tested.

Sufficient draft is ensured by the height of the chimney pipe - it must be raised above the firebox by at least 4 meters.

How to lay a firebox out of brick

This model requires the use of only fireclay (clay) bricks - ceramic or silicate bricks will immediately crack. The masonry is carried out using clay mortar, the proportions of the composition are indicated above. A pit is dug under the base of the stove, the soil at the bottom is compacted and filled with concrete mortar. The size of the foundation is 1200x400x100 mm.

After the base has hardened, it is protected with a sheet of basalt cardboard, then they begin to lay out the firebox, vertical chimney and loading chamber. A door is attached to the front of the firebox for removing ash. After the clay solution has dried, the trench is filled up, and a pipe of the required diameter is inserted into the vertical chimney. The cavities between the brick and the pipe should be filled with insulation - basalt wool, ash or other non-flammable material, for example, asbestos.

Now a cap Ø 600 mm is placed on the masonry - a cut-out lid from a metal barrel will do. Before installation, a hole is cut in it into which a pipe is inserted under the chimney. When putting on this cap, the barrel should be turned over, and the pipe will be where it is needed. Then the chimney is brought out - either directly to the street, or through the arrangement of a sunbed with horizontal chimney channels. The lounger can be laid out with ordinary sand-lime brick, since the temperature of the gases will already be low.

Let's say right away: the rocket stove is a simple and convenient heating and cooking device using wood fuel with good, but not exceptional parameters. Its popularity is explained not only by its catchy name, but moreover by the fact that it can be made with one’s own hands and not by a stove maker or even a mason; if necessary - literally in 15-20 minutes.

And also because, by investing a little more work, you can get a wonderful bed in your home without resorting to building a complex, expensive and bulky Russian or bell-type stove. Moreover, the very principle of the design of the rocket stove gives greater freedom to design and the manifestation of creativity.

Rocket stove - wood fuel device

But what is perhaps more remarkable is the “jet furnace” for the huge number of, at times, completely absurd inventions associated with it. Here, for example, are a few pearls snatched at random:

• “The principle of operation of the furnace is the same as that of the MIG-25 ramjet engine.” Yes, the MIG-25 and its descendant MIG-31 did not even sit down in the bushes near the ramjet engine (ramjet engine), as they say. The 25th and 31st are powered by double-circuit turbojet engines (turbojet engines), four of which later pulled the Tu-144 and still power other vehicles. And any stove with any jet engine (RE) is technical antipodes, see below.
• “Reverse jet thrust furnace.” Is the stove flying tail first, or what?
• “How will she blow through such a pipe?” A non-pressurized oven does not blow into the chimney. On the contrary, the chimney draws from it, using natural draft. The higher the pipe, the better the pull.
• “The rocket stove is a combination of a Dutch bell stove (sic!) with a Russian stove bench.” Firstly, there is a contradiction in the definition: a Dutch oven is a channel oven, and any bell-type oven is anything but a Dutch oven. Secondly, the bed of a Russian stove warms up completely differently than a rocket stove.

Note: in fact, the rocket stove was so nicknamed because in the wrong firing mode (more on that later), it makes a loud whistling hum. A properly tuned rocket stove whispers or rustles.

These and similar inconsistencies, understandably, confuse and prevent you from making a rocket stove properly. So let's figure out what the truth is about the rocket stove, and how to use this truth correctly so that this really good stove shows all its advantages.

Furnace or rocket?

For complete clarity, we still need to figure out why a stove cannot be a rocket, and a rocket cannot be a stove. Any RD is the same as an internal combustion engine, only the escaping gases themselves act as pistons, connecting rods with a crank and transmission. In a piston internal combustion engine, already at the moment of combustion, the high temperature of the working fluid creates a lot of pressure, which pushes the piston, and it moves all the mechanics. The movement of the piston is active, the working fluid pushes it to where it itself tends to expand.

When fuel is burned in the combustion chamber of the thruster, the thermal potential energy of the working fluid is immediately converted into kinetic energy, like that of a load falling from a height: since the outlet for hot gases is open to the nozzle, they rush there. In the RD, the pressure plays a subordinate role and nowhere exceeds the first tens of atmospheres; this, for any conceivable nozzle cross-section, is not enough to accelerate the migar to 2.5 M or launch a satellite into orbit. According to the law of conservation of momentum (amount of movement), the aircraft with a taxiway receives a push in the opposite direction (recoil impulse), this is jet thrust, i.e. thrust from recoil, reaction. In a turbofan engine, the second circuit creates an invisible air shell around the jet stream. As a result, the recoil impulse is, as it were, contracted in the direction of the thrust vector, so a turbofan engine is much more economical than a simple turbofan engine.

In a stove there is no conversion of energy types into each other, therefore it is not an engine. The stove simply distributes potential thermal energy properly in space and time. From the point of view of the furnace, an ideal RD has an efficiency = 0%, because it only pulls due to fuel. From the point of view of the jet engine, the stove has an efficiency of 0%, it only dissipates heat and does not draw at all. On the contrary, if the pressure in the chimney rises to or above atmospheric pressure (and without this, where will the jet thrust or active force come from?), the stove will at least smoke, or even poison the residents or start a fire. The draft in the chimney is without pressurization, i.e. without external energy consumption, it is ensured due to the temperature difference along its height. Potential energy here, again, is not converted into any other energy.

Note: in a rocket thruster, fuel and oxidizer are supplied to the combustion chamber from the tanks, or they are immediately refueled into it if the thruster is powered by solid fuel. In a turbojet engine (TRE), the oxidizer is atmospheric air– is pumped into the combustion chamber by a compressor driven by a turbine in the exhaust gas flow, the rotation of which consumes some of the energy of the jet stream. In a turboprop engine (TVD), the turbine is designed so that it selects 80-90% of the jet power, which is transmitted to the propeller and compressor. In a ramjet engine (ramjet), the air supply to the combustion chamber is ensured by hypersonic speed pressure. A lot of experiments have been carried out on ramjet engines, but there have been no production aircraft with them, there are none, and there are no plans to do so, as ramjet engines are too capricious and unreliable.

Kan or not Kan?

Among the myths about the rocket stove, there are some that are not entirely absurd, and even somewhat justified. One of these misconceptions is the identification of the “racket” with the Chinese kan.

The author had the opportunity to visit the Amur region in winter, in the Blagoveshchensk region, as a child. Even then there were a lot of Chinese living in the villages there, fleeing in all directions from the cultural revolution of the Great Chairman Mao and his completely frostbitten Red Guards.

Winter in those parts is not like Moscow, frost of -40 is common. And what amazed and aroused interest in stoves in general was how Chinese fanzas were heated by canals. Firewood is transported to Russian villages by carts, and smoke comes out of the chimneys in a column. And all the same, in a hut made of logs not the size of a child’s girth, by morning the corners from the inside were frozen. And the fanza is built like a country house (see picture), the windows are covered with fish bladder or even rice paper, bunches of wood chips or twigs are placed in the can, but the room is always warm.

However, there are no subtle thermal engineering wisdom in the can. This is an ordinary, only small, kitchen stove with a lower exit into the chimney, and most of the chimney itself is a long horizontal channel, a hog, on which a stove bench is located. The chimney, for fire safety reasons, is outside the building.

The effectiveness of the can is determined primarily by the thermal curtain it creates: the couch goes around, if not the entire perimeter from the inside, except for the door, then certainly 3 walls. Which once again confirms: the design and parameters of the stove must be linked to those of the heated room.

Note: the Korean ondol stove operates on the principle of a warm floor - a very low stove occupies almost the entire area of ​​the room.

Secondly, in the very cold, the Kans were drowned with argal - the dried droppings of ruminant animals, domestic and wild. Its calorific value is quite high, but argal burns slowly. In fact, an argal fire is already a long-burning stove.

It is not the Russian custom to constantly stick twigs into the oven, and our men disdained to cook food in cattle feces. But travelers of the past highly valued argal as a fuel; they collected it along the way and took it with them, carefully protecting it from getting wet. N. M. Przhevalsky in one of his letters stated that without argal he would not have been able to conduct his expeditions in Central Asia without losses. And the British, who disdained argal, had 1/3-1/4 of the detachments’ personnel returning to base. True, he was recruited from sepoys, Indian soldiers in English service, and pandits - spies recruited from the local population. One way or another, the highlight of the rocket stove is not at all the bed on the hog. To get to it, you will have to learn to think like an American: all the primary sources on the rocket furnace are from there, and utter speculation is generated only and only by misunderstanding.

How to deal with rockets?

With our view of things, it is necessary to study the original technical documentation of rocket stoves with caution, but not at all because of inches-millimeters, liters-gallons and the intricacies of American technical jargon. Although they also mean a lot.

Note: a textbook example is “Naked conductor runs under the carriage.” Literary translation - a naked conductor runs under the carriage. And in the original Petroleum Engineer article, this meant “Bare wire runs under the crane trolley.”

The rocket stove was invented by members of survival societies - people with a unique way of thinking, even by American standards. In addition, they were not bound by any standards and norms, but, like all Americans, they automatically always converted everything into money, taking into account their own benefit; a person with a different worldview simply will not get along in America. And instinctive self-interest inevitably gives rise to egocentrism. He by no means excludes good deeds, but not out of spiritual impulse, but with the expectation of dividends. Not in this life, so in that one.

Note: How afraid the average citizen of the greatest empire in history is of everything can only be understood by talking to them long enough. And sociopsychologists go out of their way to convince you that living in fear is normal and even cool. The rationale is clear: intimidated biomass is easily predictable and manageable.

Without heating and cooking, of course, you cannot survive. What is a stove for? For the time being, survivors were content with camp stoves. But then, according to the Americans themselves, in 1985-86. they were greatly impressed by two films that were released with a short interval and triumphantly went around all the screens of the world: the Soviet science fiction parody of the entire human race “Kin-dza-dza” and the Hollywood “The Day After”, about the global nuclear war.

The survivors realized that after the nuclear winter there would be no extreme romance, but there would be the planet Plyuk in the Kin-dza-dza galaxy. The newly-minted plukans will have to be content with “ka-tse” in small quantities, bad, expensive and difficult to obtain. Yes, in case anyone hasn’t watched “Kin-dza-dza” - ka-tse in Plyukan style, a match, a measure of wealth, prestige and power. It was necessary to come up with your own furnace; none of the existing ones are designed for post-nuclear blast.

Americans are very often endowed with a sharp mind, but a deep mind is found as a rare exception. A completely normal US citizen with an IQ above average may sincerely not understand how it is that someone else does not get what he himself has already “caught up with” and how someone else may not like what suits him.

If an American has already understood the essence of the idea, then he brings the product to its possible perfection - what if a buyer is found, you can’t sell raw iron. But technical documentation, which looks beautiful and neat, can be drawn up extremely carelessly, or even deliberately distorted. What's wrong with this, this is my know-how. Maybe I'll sell it to someone. Either there will be a trick or not, but for now know-how costs money. In America, such an attitude to business is considered quite honest and worthy, but there, a clinical alcoholic at work as a stopper would never miss a job and wouldn’t take a couple of bolts home for the farm. That, in general, is what all of America stands for.

And Russian breadth of soul is also a double-edged sword. Most often, just from the sketch, our master immediately understands how this thing works, but in the details he turns out to be careless and overly trusting of the source code: how is it for a fellow craftsman to deceive his own man. If something isn’t there, well, it’s not necessary. It seems clear how everything is spinning there - my hands are already itching. And then, perhaps, until it comes to the hammer, chisel and accompanying literature, still counting and counting. Moreover, important points can be omitted, veiled or deliberately incorrect.

Note: an American acquaintance once asked the author of this article - how did we, really stupid ones, choose the very smart Reagan as president? And you, who are really smart, tolerate a slobbering senile with dyed eyebrows in the Kremlin? True, then in America no one in a bad dream would have dreamed that in the next century a black citizen with a Muslim name would be installed in the Oval Office, and his first lady would dig up a vegetable garden near the White House and begin to grow turnips there. Times is changing, as Bob Dylan once sang for a completely different reason...

Sources of misunderstandings

There is such a thing in technology - the square-cube law. Simply, when the size of something changes, its surface area changes by the square, and its volume changes by the cube. Most often this means changing the overall dimensions of the product according to the principle of geometric similarity, i.e. You can't just keep the proportions. In relation to solid fuel stoves, the square-cube law is doubly valid, because the fuel also obeys it: it releases heat from the surface, and its reserve is contained in the volume.

Note: a consequence of the square-cube law - any specific stove design has a certain permissible range of its size and power, within which the specified parameters are ensured.

Why, for example, can’t you make a potbelly stove the size of a refrigerator and with a power of about 50-60 kilowatts? Because a potbelly stove, in order for it to provide any heat, must itself be heated inside to at least 400-450 degrees. And in order to warm up the volume of the refrigerator to such a temperature at a given heat transfer, you need as much firewood or coal as will not fit in it. A mini-potbelly stove will also be of no use: the heat will escape through the outer surface of the stove, which has grown relative to its volume, and the fuel will not release more of it than it can.

The square-cube law applies threefold to the rocket stove, because she is “polished” in an American professional way. With our kondachka it is better to stay away from her. For example, here in Fig. an American development, which, judging by its demand, many of our craftsmen take as a prototype.

Original drawing of a mobile rocket oven

The fact that the exact type of fire clay is not indicated here will be sorted out by ours. But, to be honest, who noticed that, judging by the absence of an external chimney and the presence of transportation holes (carrying pipe), this stove is mobile with an open firebox? And most importantly - the fact that her drum used a 20-gallon barrel with a diameter of 17 inches (431 mm with change)?

Judging by the designs from the RuNet - no one at all. They take this thing and adjust it according to the principle of geometric similarity to a domestic 200-liter barrel with a diameter of 590 mm on the outside. Many people think of setting up a ash pit, but the bunker is left open. The exact proportions of vermiculite and perlite for lining the riser and molding the furnace body (core) are not specified? We make the lining homogeneous, although from what follows it will be clear that it should consist of an insulating and accumulating part. As a result, the stove roars, it only eats dry fuel, and a lot of it, and before the end of the season it becomes covered in smoke inside.

How was the rocket stove born?

So, without science fiction and futurology, the survivalists needed a stove to heat the house, working with high efficiency on low-quality random wood fuel: wet wood chips, twigs, bark. Which, in addition, will need to be reloaded without stopping the furnace. And it most likely won’t be possible to dry it in a woodshed. Heat transfer after heating is needed for at least 6 hours to get enough sleep; getting burned in your sleep on Plyuk is no better than in America. Additional conditions: the design of the furnace should not contain complex metal products, non-metallic materials and components that require production equipment for manufacturing, and the furnace itself must be accessible for construction by an unskilled worker without the use of power tools and complex technologies. Of course, no supercharging, electronics or other energy dependencies.

They immediately took a bed from the kana, but what about the fuel? For a bell-type furnace, it requires high quality. Long-burning stoves even operate on sawdust, but only dry ones, and do not allow stopping with additional loading. They were nevertheless taken as a basis; the high efficiency achieved by simple methods was very attractive. But in attempts to make “long stoves” work on bad fuel, another circumstance became clear.

What is wood gas?

The high efficiency of long-burning furnaces is achieved largely due to the afterburning of pyrolysis gases. Pyrolysis is the thermal decomposition of solid fuel into volatile combustible substances. As it turned out (and the survivors have their own research centers with highly qualified specialists), the pyrolysis of wood fuel, especially wet wood, continues for quite a long time in the gas phase, i.e. The pyrolysis gases that have just been released from the wood still require quite a lot of heat to form a mixture that can burn out completely. This mixture was called wood gas.

Note: in RuNet, woodgas has created further confusion, because... in American vernacular gas can mean any fuel, cf. eg gas station - gas station, gas station. When translating primary sources without knowing American technical knowledge, it turned out that woodgas is simply wood fuel.

Before that, no one had seen wood gas: in conventional stoves it is formed immediately in the firebox, due to the excess energy of flaming combustion. The designers of long-burning furnaces came to the conclusion that the primary air needs to be heated, and the exhaust gases must be retained in a significant volume over a large mass of fuel, simply by trial and error, so they also overlooked wood gas.

This was not the case when burning bundles of twigs: here the draft immediately pulled the primary pyrolysis gases into the chimney. Wood gas could have formed in it at some distance from the firebox, but by that time the primary mixture had cooled, pyrolysis stopped, and heavy radicals from the gas settled on the walls of the chimney as soot. Which quickly tightened the channel completely; Hobbyists who build rocket stoves at random are familiar with this phenomenon. But the survival researchers eventually realized what was going on, and still made the necessary stove.

Who are you, the Rocket Stove?

There is an unspoken rule in technology: if it seems that it is impossible to create a device according to the given requirements, then, smart guy, read your school textbooks. That is, go back to basics. In this case, to the basics of thermodynamics. Survivors do not suffer from sick pride; they turned to the basics. And they found the main operating principle of their furnace, which has no analogues in others: slow adiabatic afterburning of pyrolysis gases in a weak flow. In long-burning furnaces, afterburning is equilibrium isothermal, requiring a large buffer volume subject to the square-cube law and an energy reserve in it. In pyrolysis gases in the afterburner expand almost adiabatically, but almost into the free volume. And now we are learning to think like an American.

How does a rocket stove work?

A diagram of the final fruit of the survivors' labors is shown on the left side of Fig. Fuel is loaded vertically into the bunker (Fuel Magazine) and burns, gradually settling down. Air enters the combustion zone through the ash pan (Air Intake). The blower should provide excess air so that it is enough for afterburning. But not excessively, so that the cold air does not cool the primary mixture. With vertical loading of fuel and a blind hopper lid, the flame itself acts as a regulator, although not very effective: when it gets too hot, it pushes out the air.

Construction of rocket furnaces

Then things begin to become non-trivial. We need to heat up a large oven with good efficiency. The square-cube law does not allow it: the meager heat will immediately dissipate so much that pyrolysis will not reach the end, and the thermal gradient from the inside to the outside will not be enough to transfer heat into the room; everything will whistle down the pipe. This law is harmful, you can’t break it in the forehead. Okay, let's look at the basics to see if there is anything there that is beyond his control.

Well, yes, there is. The same adiabatic process, i.e. thermodynamic without heat exchange with the environment. There is no heat exchange - the squares rest, and the cubes can be reduced either to a thimble or to a skyscraper.

Let's imagine a volume of gas completely isolated from everything else. Let's say energy is released in it. Then the temperature and pressure will begin to increase until the energy release stops and freeze at a new level. Great, we have completely burned the fuel, hot flue gases can be released into a heat exchanger or heat accumulator. But how to do this without technical difficulties? And most importantly, how to supply air for afterburning without violating the adiabatics?

And we will make the adiabatic process nonequilibrium. How? Let the primary gases immediately from the combustion source go into a pipe covered with high-quality insulation with a low intrinsic heat capacity (Insulation). Let’s call this pipe a fire tube or a combustion tunnel (Burn Tunnel), but we won’t sign it (know-how! If you don’t catch up, give us money for drawings and consultations! Without theory, of course. Who sells fixed capital at retail.) On the diagram, so that not accused of “opacity”, let’s denote it with flame.

Along the length of the flame tube, the adiabatic index changes (this is a nonequilibrium process): the temperature first drops slightly (wood gas is formed), then increases sharply, and the gas burns out. You can release it into the accumulator, but we forgot - what gases will be pulled through the flame tube? Supercharging means energy dependence, and there will not be an exact adiabatic, but something mixed with an isobar, i.e. efficiency will drop.

Then we will lengthen the pipe by half, maintaining the insulation, so that the heat does not go away in vain. We bend the “idle” half up, making the insulation on it weaker; We’ll think about how to preserve the heat seeping through it a little later. In a vertical pipe there will be a temperature difference in height, and, therefore, draft. And a good one: the thrust force depends on the temperature difference, and with an average temperature in the flame tube of about 1000 degrees, it is not difficult to achieve a difference of 100 at a height of about 1 m. So, while we have made a small, economical stove-stove, now we need to think about how to use its heat.

Yes, it doesn’t hurt to further encrypt it. If we call the vertical part of the flame tube a primary or internal chimney, then they will guess the main idea, but we are not the smartest in the world. Well... let's call the primary chimney the most common technical term for vertical pipes with rising current - a riser. Purely American: correct and unclear.

Now let's remember about heat transfer after heating. Those. we need a cheap, always available and very capacious heat accumulator. There is nothing to invent here; adobe (Thermal Mass) was invented by the primitives. But it is not fire-resistant, it does not hold more than 250 degrees, and at the mouth of the riser we have about 900.

It is not difficult to convert high-potential heat into medium-potential heat without losses: you need to give the gas the opportunity to expand in an isolated volume. But, if you leave the expansion adiabatic, then the volume needed is too large. This means it is material and labor intensive.

I had to go back to basics again: immediately after leaving the riser, let the gases expand at constant pressure, isobarically. This requires heat removal to the outside, about 5-10% of the thermal power, but it will not be lost and will even be useful for quickly warming up the room during the morning fire. And further along the flow of gases – cooling is isochoric (in a constant volume); Thus, almost all the heat will go into the battery.

How to do this technically? Let's cover the riser with a thin-walled iron drum (Steel Drum), which will also prevent heat loss from the riser. The “drum” turns out to be a bit high (the riser sticks out a lot), but it doesn’t matter: we will coat it 2/3 of the height with the same adobe. We attach a stove bench with an airtight chimney (Airtight Duct), an external chimney (Exhaust Vent), and the stove is almost ready.

Note: the riser and the drum covering it look similar to stove hood above the elongated heil. But the thermodynamics here, as we see, are completely different. It is useless to try to improve a bell-type stove by building on it - only extra material and work will go away, and the stove will not get any better.

It remains to solve the problem of cleaning the channel in the bed. To do this, the Chinese have to break down the kan from time to time and wall it up again, but we are not in the 1st century. BC. We live when kan was invented. We will install a secondary ash pit (Secondary Airtight Ash Pit) with a sealed cleaning door immediately after the drum. Due to the sharp expansion and cooling of the flue gases in it, everything in them that has not burned out immediately condenses and settles. This ensures the cleanliness of the external chimney for years.

Note: the secondary cleaning will have to be opened once or twice a year, so you don’t have to bother with the valve loops. Let's just make a lid from a metal sheet with screws and a mineral cardboard gasket.

Small rocket

The next task of the designers was to create a small continuous combustion stove on the same principle for cooking food in the warm season. IN heating season The drum cover (Optional Cooking Surface) of a large oven is suitable for cooking; it heats up to about 400 degrees. The small rocket stove had to be portable, but it was permissible to make it with an open firebox, because When it’s warm, you can cook outdoors or under a canopy.

Here the designers took revenge on the square-cube law by making it work for themselves: they combined the fuel bunker with the blower, see fig. at the beginning of the section on the right. This cannot be done in a large furnace; precise adjustment of the furnace mode as the fuel settles (see below) will be impossible.

Here, the volume of incoming primary air (Primary Air) turns out to be small relative to the area of ​​heat release and the air can no longer cool the primary mixture until pyrolysis stops. Its supply is regulated by a slot in the hopper lid (Cover Lid). The hopper, inclined at 45 degrees, optimizes the automatic adjustment of oven power for standard culinary procedures, but it is more difficult to make.

Secondary air for afterburning wood gas in small oven enters through additional holes in the mouth of the riser or simply leaks under the burner if a cooking vessel is placed on it. If the small stove is close to the maximum size (about 450 mm in diameter), then for complete afterburning you may need an Optional Secondary Woodgas Frame).

Note: Supply secondary air to the riser mouth of a large kiln through holes in the drum (which would increase Furnace efficiency) it is forbidden. Although the pressure in the entire gas and smoke path is lower than atmospheric, as it should be in a furnace, due to strong turbulence, flue gases will be emitted into the room. This is where their kinetic energy, which is harmful to the furnace, comes into play; This is perhaps the only thing that a rocket stove has in common with a jet engine.

The small rocket stove revolutionized the class of camping stoves, especially camping stoves. A wood chip stove (Bond stove in the West) will help you cook a stew or wait out a snowstorm in a one- or two-person tent, but it won’t save a group caught in a spring hike by belated bad weather. A small rocket stove is only slightly larger; it can be quickly made out of nothing, but is capable of developing power up to 7-8 kW. However, we’ll talk about rocket stoves made from just about anything later.

Also, the small rocket stove gave rise to many improvements. For example, Gabriel Apostol provided it with a separate blower and a wide bunker. The result was a stove suitable for constructing a compact and fairly powerful water heater, see the video below. The large rocket oven was also modified, we will talk about this a little at the end, but for now we will focus on more significant things.

Video: water heater based on a rocket stove designed by Gabriel Apostol

How to sink a rocket?

A rocket stove with long-burning stoves has general property: you need to run them only on a warm pipe. For a small one this is unimportant, but a large one on a cold chimney will only burn fuel in vain. Therefore, before loading standard fuel into the bunker after a long break in the firebox and kindling, a large rocket stove needs to be accelerated - fired with paper, straw, dry shavings, etc., they are placed in an open ash pit. The end of acceleration is judged by a change in the tone of the furnace hum or its subsidence. Then you can load fuel into the bunker, and it will ignite automatically from the booster fuel.

The rocket stove, unfortunately, is not one of the stoves that is completely self-adjusting to fuel quality and external conditions. At the beginning of combustion of standard fuel, the ash door or hopper lid in a small furnace is opened completely. When the stove starts to hum loudly, cover it “to the point of a whisper.” Further, during the combustion process, it is necessary to gradually cover the access of air, guided by the sound of the stove. Suddenly the air damper slammed shut for 3-5 minutes - no big deal, if you open it, the stove will light up again.

Why such difficulties? As the fuel burns, the flow of air into the combustion zone increases. When there is too much air, the furnace explodes, but do not rejoice: now the excess air cools the primary gas mixture, and the sound intensifies because the stable vortex in the riser is knocked into a chaotic lump. Pyrolysis in the gas phase is interrupted, no wood gases are formed, the furnace consumes too much fuel, and a deposit of soot cemented with bituminous particles settles in the riser. Firstly, this is a fire hazard, but most likely it won’t lead to a fire; the riser channel will quickly become completely overgrown with carbon deposits. How to clean it if you have a non-removable drum cover?

In a large furnace, a spontaneous change of mode occurs abruptly, when the top of the sticks drops to the bottom edge of the hopper, and in a small furnace - gradually, as the fuel mass settles. Since an experienced housewife does not leave her side for a long time when cooking on the stove, the designers considered it possible to combine a bunker with a blower in it for the sake of compactness.

This trick will not work with a large stove: the high riser pulls very hard, and the air gap needs to be so thin (and it also needs to be adjusted) that it is impossible to achieve a stable stove mode. It’s easier with a separate blower: it’s easier for the air to flow around the sides of a mass of fuel that is round in cross-section, and a flame that gets too hot pushes it there. The stove turns out to be self-regulating to some extent; however, within very small limits, so you still have to manipulate the blower door from time to time.

Note: it is impossible to make a bunker for a large oven for the sake of simplicity without a tight lid, as is often done. Due to the unregulated additional air flow through the fuel mass, it is unlikely to be possible to achieve stable operation of the furnace.

Materials, sizes and proportions, lining

Now let's see what a homemade rocket stove should look like from the materials available to us. Here, too, we need to be careful: not everything that is at hand in America is what we have, and vice versa.

Of what?

For a large stove with a stove bench, more or less reliable experimental data is available for products with a drum from a 55-gallon drum with a diameter of 24 inches. 55 gallons is 208-odd liters, and 24 inches is almost exactly 607 mm, so our 200-liter is quite suitable without additional conversion. While maintaining the oven parameters, the diameter of the drum can be halved, to 300 mm, which makes it possible to make it from 400-450 mm tin buckets or a household gas cylinder.

Pipes will go to the ash pit, bunker, firebox and riser different sizes, see below, round or profile. This way it will be possible to make an insulating lining of the firebox from a mixture of equal parts of oven clay and crushed fireclay, without resorting to brickwork; We’ll talk about the riser lining in more detail below. Combustion in a rocket furnace is weak, therefore the thermochemistry of gases is gentle and the thickness of the steel of all metal parts, except for the gas pipeline in the stove bench, is from 2 mm; the latter can be made from a thin-walled metal corrugated sheet, here the flue gases are already completely exhausted both in terms of chemistry and temperature.

For external coating, the best heat accumulator is adobe. If the dimensions indicated below are observed, the heat transfer of a rocket stove in adobe after combustion can reach 12 hours or more. The remaining parts (doors, covers) are made of galvanized metal, aluminum, etc., with sealing gaskets made of mineral cardboard. Conventional stove fittings are not suitable, it is difficult to ensure their tightness, and a cracked rocket stove will not work properly.

Note: it is advisable to equip the rocket stove with a view in the external chimney. Although the gas vent in the high riser seals the overall smoke path tightly, strong winds outside can suck the heat out of the bench prematurely.

Dimensions and proportions

The basic calculated values ​​to which the rest are tied are the drum diameter D and its internal cross-sectional area S. Everything else, based on the size of the available iron, is determined as follows:

1. Drum height H – 1.5-2D.
2. Drum coating height – 2/3H; For the sake of design, the edge of the coating can be made oblique and curved, then 2/3H must be maintained on average.
3. The thickness of the drum coating is 1/3D.
4. Riser cross-sectional area – 4.5-6.5% of S; It's better to stay within 5-6% of S.
5. The height of the riser is the larger the better, but the gap between its edge and the drum tire must be at least 70 mm; its minimum value is determined by the viscosity of the flue gases.
6. The length of the flame tube is equal to the height of the riser.
7. The cross-sectional area of ​​the flame tube (fire duct) is equal to that of the riser. It is better to make the fire duct from a square corrugated pipe, so the furnace mode will be more stable.
8. The cross-sectional area of ​​the blower is 0.5 of its own firebox and riser. A more stable furnace mode and its smooth adjustment will be provided by a rectangular corrugated pipe with sides 2:1, laid flat.
9. The volume of the secondary ash pan is from 5% of the original volume of the drum (excluding the volume of the riser) for a stove from a barrel to 10% of the same for a stove from a cylinder. Interpolation for intermediate drum sizes is linear.
10. The cross-sectional area of ​​the external chimney is 1.5-2S.
11. The thickness of the adobe cushion under the external chimney is 50-70 mm; if the channel is round, it is counted from its lowest point. If the bed is on wooden floors, the pillow under the chimney can be halved.
12. The height of the coating of the stove bench above the external chimney is from 0.25D for a 600 mm drum to 0.5D for a 300 mm drum. You can do less, but then the heat transfer after heating will be shorter.
13. The height of the external chimney is from 4 m.
14. The permissible length of the gas duct in the bed - see next. section

The maximum thermal power of a rocket stove made from a barrel is approximately 25 kW, and a stove made from a gas cylinder is about 15 kW. The power can be adjusted only by the size of the fuel load. By supplying air, the oven is put into operation, and nothing more!

Note: in the original survivalist stoves, the riser cross-section was taken at 10-15% S based on very wet fuel. Then, there, in America, rocket stoves with a bench for bungalows appeared, designed for air-dry fuel and more economical. In them, the riser cross-section is reduced to the recommended ones and here it is 5-6% S.

Riser lining

The efficiency of a rocket stove largely depends on the thermal insulation of the riser. But American lining materials, alas, are not available to us. In terms of reserves of high-quality refractories, the United States has no equal; there they are considered strategic raw materials and are sold even to trusted allies with caution.

From our available materials for heating engineering, they can be replaced with light fireclay bricks of the ShL brand and ordinary self-excavated river sand with a large admixture of alumina, correctly laid, see below. However, these materials are porous; in the oven they will quickly become saturated with carbon deposits. Then the oven will roar with any air supply, with all that follows. Therefore, we need to surround the riser lining with a metal shell, and the end of the lining must be covered with oven clay.

Lining diagrams for 3 types of furnaces are shown in Fig. The point here is that as the size of the drum decreases, the share of its direct heat transfer through the bottom and unlined part increases according to the square-cube law. Therefore, while maintaining the desired thermal gradient in the riser, the lining power can be reduced. This makes it possible to correspondingly increase the relative cross-section of the annular lowering of the flue gases in the drum.

Schemes of riser lining in rocket furnaces

For what? Firstly, the requirements for the external chimney are reduced, because The external rod now pulls better. And since it pulls better, then the permissible length of the hog in the bed drops more slowly than the size of the stove. As a result, if a stove from a barrel heats a stove bench with a length of up to 6 m, then a stove made from a cylinder is half as long - 4 m.

How to line with sand?

If the riser lining is fireclay, then the residual cavities are simply filled with construction sand. There is no need to carefully prepare a river self-dug for lining entirely from sand; just select large debris. But they pour it in layers, in 5-7 layers. Each layer is compacted and sprayed until a crust forms. Then the entire backfill is dried for a week, the top edge is covered with clay, as already mentioned, and the construction of the furnace continues.

Balloon rocket

From the above, it is clear that it is more profitable to make a rocket stove from a gas cylinder: less work, there are fewer unsightly parts in sight, and the stove warms up almost the same. A thermal curtain or a warm floor in Siberian frost will heat a room of 50 square meters with a power of 10-12 kW. m or more, so here, too, a balloon rocket turns out to be more profitable; a large barrel will rarely have to be launched at full power with maximum efficiency.

The craftsmen apparently understood this too; at least some. For example, here in Fig. – drawings of a balloon furnace-rocket. On the right is the original; the author seems to have wisely understood the initial developments and, in general, everything turned out right for him. On the left are the necessary improvements taking into account the use of air-dry fuel and heating the bed.

Drawings of a rocket stove from a gas cylinder

A fruitful idea is a separate supply of heated secondary air. The furnace will be more economical and the fire tube can be made shorter. The cross-sectional area of ​​its air duct is about 10% of the riser cross-section. The oven always operates with the secondary completely open. First, the mode is set by the primary valve; Precisely adjust with the hopper lid. At the end of the firebox, the stove will roar, but here it’s not so scary; to clean the riser, the author of the design provides a removable drum cover. It, of course, must have a seal.

Rockets made from anything

Canning

Scheme of a rocket stove made from cans

Tourists, hunters and fishermen (many of them members of survival societies) soon adapted the small rocket stove into a camp stove made from empty tins. It was possible to reduce the influence of the square-cube to a minimum by using horizontal fuel supply, see the diagram on the right. True, at the cost of some inconvenience: the sticks need to be pushed inward as they burn out. But the furnace mode began to hold fast. How? Due to the automatic redistribution of air flows through the plenum and over/through the fuel. The power of a can rocket stove lies in the range of 0.5-5 kW depending on the size of the stove and is regulated by approximately three times the amount of fuel loading. The basic proportions are also simple:

• The diameter of the combustion chamber (combustion chamber) is 60-120 mm.
• The height of the combustion chamber is 3-5 times its diameter.
• The cross-section of the blower is 0.5 from its own combustion chamber.
• The thickness of the thermal insulation layer is not less than the diameter of the combustion chamber.

These proportions are very approximate: changing them by half does not prevent the stove from working, and efficiency on a hike is not so important. If the insulation is made of wet sandy loam, as described above, the joints of the parts can simply be coated with clay (left position in the figure below). Then, after 1-2 fires, the stove will acquire strength that allows it to be transported without special precautions. But in general, any of the available non-combustible materials will do the insulation, trace. two pos. A burner of any design must provide free air flow, 3rd position. A rocket stove welded from a steel sheet (right position) with sand insulation is twice as light and economical as a potbelly stove of the same power.

Compact rocket stoves

Brick

Rocket stove made from broken bricks

We won’t talk about large stationary rocket furnaces: all the original thermodynamics are in tatters in them, and they are deprived of one of the main advantages of the original furnace - ease of construction. We'll tell you a little about rocket stoves made from brick, clay or stone fragments, which can be made in 5-20 minutes when you don't have tins at hand.

Here, for example (see video below), is a thermodynamically complete rocket oven made of 16 bricks laid dry. The voice acting is in English, but everything is clear even without words. A similar one can be built from fragments of brick (see figure), cobblestones, or sculpted from clay. A stove made from rich earth is enough for one time. The efficiency of all of them is not so great, the height of the combustion chamber is too small, but it is enough for pilaf or to quickly warm up.

Video: rocket oven made of 16 bricks (eng)

New material

Diagram of the Shirokov-Khramtsov furnace

Among the domestic developments, the Shirokov-Khramtsov rocket stove deserves attention (see figure on the right). The authors, not caring about survival in the splash, used modern material– heat-resistant concrete, adjusting all thermodynamics to it. The components of reinforced concrete are not cheap; a concrete mixer is needed for mixing. But its thermal conductivity is much lower than that of most other refractories. The new rocket stove began to work more stable, and it became possible to release some of the heat outside in the form of infrared radiation through heat resistant glass. The result was a rocket stove - a fireplace.

Do rockets fly in a bathhouse?

Wouldn't a rocket stove be suitable for a sauna? It seems like you can build a heater on the drum cover. Or a flow one instead of a bed.

Unfortunately, the rocket stove is not suitable for a bathhouse. To obtain light steam, the sauna stove should immediately warm up the walls with thermal (IR) radiation, and immediately, or a little later, the air, by convection. To do this, the oven must be a compact source of infrared and a convection center. Convection from a rocket furnace is distributed, and it provides little IR at all; the very principle of its design excludes significant losses due to radiation.

In conclusion: to the rocket makers

Successful designs of rocket stoves still rely more on intuition than on precise calculations. Therefore, good luck to you too! – the rocket stove is a fertile field for craftsmen with a creative streak. Published

P.S. And remember, just by changing your consciousness, we are changing the world together! © econet

The jet furnace is gaining significant popularity today. Every day more and more people learn about the features of this heating system. This oven is very energy efficient. You can do it yourself. She will from a gas cylinder, brick or other materials – it’s up to you.

How does it work. Materials for work

Before you do DIY design, you need to understand exactly how it works. Air enters along with oxygen through the duct for further combustion. Thermal energy enters the firebox in sufficient quantities. You can have a stove. Combustion temperature may exceed +1200 degrees.

The design is intended. In this mode, it does not need any special regulation of the air supply.

To make such a stove with your own hands, you can use simple materials at hand. But it is still recommended to find and apply the following:

• metal barrel – 200 liters;
• drum for a stove with a stove bench;
• profile pipes of various diameters;
• for external treatment - a mixture based on straw and clay soil;
• galvanized sheet metal.

How to heat this stove

All long-burning stoves can be easily lit if the pipe is warm. The reaction furnace is not any particular exception. When the downtime was quite long, it will definitely be necessary pre-overclocking. To do this you can use:

• straw;
• paper;
• dry shavings.

There are many versions explaining why the jet stove they called it that way. One of them produces a rather characteristic hum during operation. When its tone decreases significantly, the acceleration can be considered complete. Therefore, you can start adding main fuel. When combustion just begins, the ash door must be opened. Her close a little, when the hum starts to increase.

We build a long-burning stove for the garage with our own hands

First of all, let's see how to make a jet jet for your garage with your own hands. This option is the simplest, especially if you follow the drawings and all the necessary dimensions on them. For example, let's take a propane-based gas cylinder with a diameter of 300 millimeters. The loading hopper and firebox will be steel pipe measuring 150 millimeters.

Read also: Making a stove for the garage

We cut off the required length from the pipe and remove the upper part from the cylinder. We take the drawings and weld all the parts according to them. Do not forget to put insulating material between all vertical pipes. material. Sand is quite suitable for this.

This design weighs relatively little and is suitable for heating a garage great fit. When you place the entire structure on the floor in the garage, you will need to weld the legs to it. In the garage you can make your own jet stove from bricks.

Building such a structure is a little more difficult. Fire channels must be made of fireclay bricks. A barrel is suitable as a cap.

The future structure falls slightly below floor level. To do this, you need to dig a small hole with your own hands. Compact the bottom and along the formwork, fill in. Its thickness should be 100 millimeters. When the foundation hardens, you can begin laying. The basis of the solution is usually refractory clay. After you complete the laying, you will need to fill the hole and put an iron barrel, which has no bottom, onto the fire channel. Next, take the insulation and pour it between the brick and the barrel.

A simple and cheap design of a rocket stove began its march around the world from North America, where it remains very popular in rural areas to this day. It is known on all continents, including distant Australia. The heating unit captivates amateur enthusiasts with its simplicity and energy efficiency, which, combined with its low cost, makes it extremely attractive for manufacturing at home. Of course, a jet stove cannot heat a large house, but in a country house or in a small garden house it would be more than appropriate. Surprisingly, but true - only a few people know about this amazing design. And this is in a country where cold weather lasts longer than six months! Today we will fill this gap and tell you everything we know about the warm and cozy “rocket”, including the smallest details of how to make it yourself and the intricacies of its operation.

Jet stove - what is it?

The home heat that comes from a jet stove cannot be provided by any modern heater.

A jet stove, or, as it is also called, a rocket stove, actually has nothing in common with modern technologies. The only thing that makes this heating unit look like a space vehicle is the intense flow of flame and the humming associated with improper operation. Nevertheless, it cannot be said that the rocket stove is a completely backward device in technical terms. Despite its simple design, it uses the most advanced methods of burning solid fuels:

• pyrolytic combustion of gases released during dry distillation of solid fuel;
• movement of gaseous products through the furnace channels, which does not require forced ejection due to draft.

This is what a simple jet-powered stove looks like

The simplest “rocket” is a curved piece of large diameter pipe. Firewood or other fuel is placed in a short horizontal section and set on fire. At first, the heating device works like an ordinary potbelly stove, but this is only until the temperature of the longer vertical part, which acts as a chimney, rises. The red-hot metal promotes the re-ignition of flammable substances and the appearance of a vacuum at the top point of the chimney. Due to increased draft, the air flow to the firewood increases, which significantly increases the burning intensity. In order to achieve even greater efficiency from this original device, the firebox opening is equipped with a door. When the cross-section of the air channel decreases, the supply of oxygen to the firewood stops and its pyrolytic decomposition into gaseous hydrocarbons begins. But in such a simple installation they will not burn completely - for this you will need to set up a separate area for afterburning the flue gases. By the way, it is this, as well as the thermal insulation of the chimney, that allows more complex “rockets” to successfully compete with other solid fuel units. As for the simplest design we are considering, it is often used for cooking or heating food. All that is required for this is to equip a convenient platform for a pot or kettle on the vertical section of the stove.

Geography of application of rocket heating units

Being a simple and convenient heating and cooking unit, the rocket stove is widely used in both mobile and stationary versions. Most often it is used:

• for heating residential premises;
• as equipment for drying fruits;
• for heating greenhouses;
• to ensure normal working conditions in workshops or garages;
• to maintain above-zero temperatures in warehouses, utility buildings, etc.

Thanks to its simplicity, unpretentiousness and reliability, the jet heater enjoys well-deserved respect among fishermen and hunters, car rally enthusiasts and survivalists. There is even a special version, the purpose of which is indicated by the name - “Robinson”.

Advantages and disadvantages of the rocket stove

Despite its simple design, the rocket stove has many advantages:

• efficiency level at the level of the best examples of modern heating equipment operating on solid fuel;
• efficiency - to achieve the required temperature, the reactive unit will consume four times less firewood than a traditional oven design;
• heating temperature above 1000 °C;
• the ability to use any type of solid fuel, including dry plant waste, cones, pine needles and shavings;
• complete combustion and environmental friendliness - during operation, the flame temperature increases so much that the soot ignites. Rocket stove smoke consists primarily of water vapor and carbon dioxide;
• possibility of additional fuel loading for continuous operation of the heating device;
• simplicity and reliability;
• the presence of portable structures intended for mobile use.

The heating unit is not without its drawbacks. Operation of the device is associated with the risk of penetration into the home carbon monoxide. The stove cannot be used to heat a large house, and attempts to install a water heat exchanger in the combustion zone lead to a decrease in thermal power and disruption of normal operation. The disadvantages include the low aesthetic value of the design, which, however, is a very ambiguous statement, since for lovers of ethno-style, the design of the stove is a real find.

Types of jet heating devices. Choosing a design for self-production

Craftsmen have developed several designs of rocket stoves suitable for mobile or stationary use:

• portable units made of metal pipes, tin cans or buckets;
• jet heating devices from a gas cylinder;
• ovens built from fireclay bricks and metal containers;
• heating heat generators with a stove bench.

The most difficult to manufacture are the structures, the construction of which requires the skills of a mason. However, if you have detailed diagrams of serial layouts, even a novice home craftsman can handle this work.

Portable rocket stove

Portable rocket stoves are mass-produced by industry

Hiking options are represented by the simplest designs, which are based on the same pipe bent or welded from individual sections. The improvements affected only the installation of a partition for arranging the ash pit, in which a slot is made for air leakage. Often the lower part of the loading chamber is equipped with a grate to supply air directly to the combustion zone. The opening for storing firewood is equipped with a door, which subsequently regulates the air supply.

The requirements for a mobile design also extend to convenience during cooking, so the upper section of the chimney must be equipped with a stand for metal utensils.

Gas cylinder unit

The use of a gas cylinder is the next step in the development of jet heating devices. A more complex design can significantly increase the thermal power and efficiency of the furnace. All that is required to manufacture the installation is a household gas cylinder or a fuel barrel, sections of thick-walled steel pipes and a metal sheet 3–5 mm thick.

A rocket stove made from a gas cylinder can be used to heat small utility rooms

If you have a piece of steel pipe with thick walls and a diameter of more than 30 cm, a rocket stove can be made from it. This option will allow you to avoid labor-intensive operations associated with disassembling the factory gas tank.

How such a design works can be seen in the diagram below. Firewood loaded into the firebox burns due to the flow of air through the loading window. Afterburning of combustible gases occurs in a pipe installed inside the cylinder due to the supply of secondary air. To enhance the effect, the inner chamber is insulated, which makes it possible to raise the temperature inside above 1000 °C. Hot gases hit the bell as they move and enter the outer chamber, the walls of which act as a heat exchanger. Having given up their energy, the combustion products are discharged through a chimney embedded in the lower part of the reverse side balloon.

To create the draft necessary for stable operation of the rocket stove, the top of the chimney is raised at least 4 m relative to the loading window.

Combined rocket stove made of brick and metal barrel

The use of fireclay bricks for arranging the firebox and internal chambers of a jet heating device transforms the “rocket” into the category of stationary structures. The high heat capacity of the materials used allows heat to be accumulated and released within several hours, which is why such units are often installed in residential premises.

Furnace structure with refractory lining of the working area

Jet stove with stove bench

Like other solid fuel stoves, the "rocket" has the disadvantage that most of the heat is lost through the chimney. Despite this, certain advantages of its design make it easy to get rid of this disadvantage. The thing is that the unit was called reactive for a reason, but because of the high rate of excision of burning gases. This feature can be turned into a benefit by significantly increasing the length of the smoke exhaust channels.

Scheme of a jet stove with a stove bench

This idea found its implementation in massive stationary structures with a couch in the shape of a sofa or bed. It is successfully made from brick or rubble stone, decorated with a plastic mass of clay and sawdust. Thanks to the high heat capacity of the materials used, the stove can retain heat all night, which, combined with high efficiency, makes the heating unit very attractive for installation in residential premises.

When choosing a design for manufacturing at home, you need to take into account the features of its operation. As a camping option, choose a mobile unit - it will be enough to warm up, dry clothes and cook lunch. In order to occasionally heat small technical rooms, a portable structure made from a gas cylinder is used. If you need to heat a small country house or cottage, then there is simply no better option than a jet heating unit with a stove bench.

We build a rocket oven with our own hands

Suggested for self-made The design is the elite of rocket heating devices. After construction it long time will delight the owner with comfort and cozy warmth even in the most severe frost. As you might have guessed, we are talking about a unit with a stove bench. Despite the fact that such a design is the most complex, the diagrams, instructions and descriptions we presented will allow you to build a stove in just 2-3 days.

Device and principle of operation

A rocket furnace consists of several chambers and channels. The bunker for loading firewood is made of fireclay bricks and is equipped with an opening in the lower part for air supply. It has a refractory lining and a channel that connects the firebox with a vertical flue (fire pipe or riser). A metal barrel is used as the casing of the rocket furnace, inside of which the afterburning chamber is lined with magnesite or fireclay bricks. The heat exchanger of the heating unit is not only a steel container, but also long horizontal channels of the stove bench made of galvanized steel pipes or bricks.

The processes occurring inside a stationary reactive furnace resemble the operation of pyrolysis heating units

There is no need to use refractory materials to construct heat exchange channels. A well-burnt red brick is sufficient.

The body of the stove and trestle beds is formed from sandbags, stone or brick fragments and coated with a clay composition. Good heat storage capacity finishing materials allows the structure to release heat for several hours after the firewood has completely burned out. To remove combustion products, a high chimney is used, which can pass both indoors and outdoors.

The high performance of the “rocket” is explained by the method of fuel combustion, which tends not so much to direct-flow heating units as to pyrolysis boilers. The operation of the furnace is accompanied by the active release of gas components, which are burned in the riser. The cap helps reduce the flow rate of hot gases, otherwise they simply would not have time to oxidize. By the way, heating the upper part of the flame tube creates a vacuum at its end, due to which active combustion of the fuel occurs. In this case, such a high temperature arises in the riser that even the soot ignites. Nevertheless, at the point of transition from the vertical channel to the horizontal heat exchanger, experts recommend installing an ash pan, equipping its chamber with a small door to allow periodic maintenance.

Calculation of basic parameters, drawing

There is no need to give the exact dimensions of a rocket stove with a stove bench - its dimensions and configuration completely depend on the characteristics of the room. The presented method for calculating parameters, based on the use of the proportions of all parts of the rocket furnace, will be quite sufficient to design a high-performance, efficient unit.

To perform the calculation, it is enough to know the diameter D and height H of the external heat exchange casing (drum).

1. The height of the flame tube is at least 1.3H.
2. The gap between the riser and the cap is 0.1–0.15H.
3. External clay coating is carried out no higher than 1/3H.
4. The thickness of the heat-accumulating layer should be no more than 1/3D.
5. The cross section of the flame tube is 0.25–0.3D.
6. The height of the ash pan is up to 10% of the vertical dimensions of the casing.
7. The cross-section of the blower should be 50% smaller than the riser area.
8. The thickness of the adobe cushion above the heat exchanger is at least 1/4D.
9. The chimney height is more than 4 m.
10. The length of the horizontal heat exchanger is calculated based on the volume of the drum. If a standard fuel barrel is used, it can reach 6–8 m.

As you can see, it is not difficult to determine the dimensions of all elements of the furnace, especially since its design allows for some liberties in terms of dimensions and configuration.

For perfectionists and those who are afraid to experiment, we present a drawing of a heating unit, drawn to scale on a marked sheet of paper. If necessary, taking exact dimensions from it will not be difficult.

Drawing of a stationary jet heating system

Materials and tools

The construction of a jet furnace does not require any special equipment. The only power tools required during the work process are a welding machine and an angle grinder, and even then just for a few minutes - to separate the barrel lid and configure the heat exchanger pipes. Any owner can also find everything else:

• trowel (trowel);
• bushhammer;
• building level and plumb line;
• roulette;
• container for preparing the solution;
• bayonet shovel;
• tamping;
• buckets;
• concrete trowel.

Although the design of the “rocket” is undemanding in terms of materials, you will still have to buy some of them. Here is a list of what will be needed during the construction process:

• refractory bricks of any type;
• metal barrel for making a casing;
• a pipe Ø30–40 cm, which will hold the thermal insulation coating of the vertical channel. You can use the housing from an old water heater, a suitable capacity of an industrial receiver or a hydraulic accumulator;
• galvanized steel pipes with a diameter of more than 25 cm, which will be needed as a heat exchanger;
• a steel pipe for arranging a chimney with a diameter of 150 mm and an elbow for its outlet at 90°;
• ash pan hatch;
• blower door;
• a special heat-resistant mixture for preparing the solution (can be replaced with sand and clay);
• perlite for thermal insulation of the riser;
• Red brick;
• rubble stone or brick waste;
• sawdust or chaff.

Since the barrel will be only partially embedded in the oven, it will have to be painted to increase the aesthetic value of the unit. To do this, you will additionally need a metal brush, a solvent to degrease the metal surface, a primer and any heat-resistant paint.

Site selection and other preparatory activities

When determining the construction site, you should take into account the requirements that apply to all designs of solid fuel stoves with an open flame:

• the area of ​​the room in which it is planned to install a jet heating device with a sunbed must be at least 16 m2;
• the absence of logs (floor beams) under the stove body will greatly simplify installation;
• there should be no wooden rafters or ceilings above the fireplace;
• if part of the chimney passes through the ceiling, then the stove is installed closer to the central part of the house. In this case, the pipe can be secured near the ridge;
• You should not install a heating structure close to the outer contour of the building - precious heat will go outside. It is better to attach the unit to one of the internal walls;
• It is not recommended to build a jet device near wooden walls and partitions. In this case, separate accommodation is chosen.

It is also important how convenient it will be to light the rocket stove and throw firewood into it. To do this, the firebox is placed towards the entrance, providing at least 1 m of free space in front of it.

One of the many options for installing a stove in the middle of the room

In a small room, it is convenient to place a rocket stove in the corner, with the loading hopper oriented in one direction and the lounger in the other.

Having chosen a place, they begin to prepare it for future construction. If the room has a wooden floor, then the part of it that will be under the stove is removed. After this, a shallow pit is dug, the bottom of which is compacted using a tamper.

In addition, it is necessary to prepare a metal barrel for installation. To do this, cut off its cover along the contour. In this case, part of the thickening in the form of a metal hoop is left to ensure the rigidity of the base of the casing. Most likely, the fuel container will be dirty and rusty, so it is better to clean it before installation.

The last thing to do before starting construction is to prepare the solution. It is best to use a special heat-resistant composition, which can be bought in construction stores, but you can get by with a simple mixture of sand and clay in a ratio of 1:1 or 1:2, depending on the fat content of the latter. Water will be needed up to ¼ of the volume of dry ingredients - the output should be a composition reminiscent of thick sour cream.

Instructions for the progress of work

As already mentioned, to make a rocket stove with a stove bench, it will take much more effort and time than when making a metal unit. It will help make the task easier and reduce time step-by-step instruction with illustrations of all stages of construction.

1. The place where the firebox will be formed is deepened by 10 cm and laid out with refractory bricks, after which formwork is installed along the contour of the furnace. To strengthen the foundation, it is necessary to install reinforcement from building mesh, reinforcement Ø10–20 mm or scraps of metal pipes and corners.

   

   Arrangement of formwork

2. Lay out the base of the working chamber according to the level.

   

   The base of the loading chamber is lined with refractory bricks

3. The structure is poured with concrete. Further work can begin immediately after the solution has set. As a rule, one day is enough for this.

   

   Pouring the foundation

4. The base of the jet furnace and the combustion chamber are formed from refractory bricks laid in a continuous pattern.

   

   Rocket stove base

5. Several rows of masonry raise the side walls of the structure.

   

   The walls are formed using fireclay bricks installed on the edge

6. The lower channel of the heat-generating rocket is being equipped.
7. The combustion chamber is covered with a row of bricks laid transversely in such a way as to leave two openings open - the firebox and the riser (vertical channel).

   

   Method of covering the horizontal part of the working chamber

8. An old casing from a storage boiler is prepared for installation. To do this, the device is cut off on both sides to obtain a large-diameter pipe.

   

   Furnace parts prepared for installation

9. The lower part of the fuel and lubricants container is equipped with a flange into which the horizontal heat exchanger pipe will fit. Welds must be continuous to ensure tightness and, accordingly, safety of the structure.

   

   Installation of the lower pipe is carried out by welding

10. After the outlet pipe is cut into the barrel, it is cleaned of rust, coated with a primer and several layers of heat-resistant paint.
11. A side outlet is welded to the horizontal chimney, acting as an ash pit. To clean it, the channel is equipped with a sealed flange.
12. A fire tube is made of fireclay bricks. The shape of its internal channel is a square with a side of 18 cm. During work, be sure to control the vertical position of the structure using a plumb line or a building level.

    

    The height of the vertical channel depends on the size of the outer drum

13. A casing is installed on the flame tube, after which the gaps between the metal container and the walls of the vertical channel are filled with perlite. To avoid spillage of thermal insulation on the floor, the lower part of the riser is carefully sealed using a clay mixture.

    

    Riser thermal insulation method

14. The firebox cap is made. You can use a cut-off part of the water heater as it, providing it with a comfortable handle.
15. The furnace body is formed using brick or stone masonry. For this purpose, you can also use sandbags placed at the base of the vertical channel.

    

    The oven body can be lined with sandbags

    The unassuming spring appearance is hidden with the help of adobe coating. To make it, up to 50% of large sawdust or chaff (chaff) is added to the clay solution.

    

    Coating the furnace body

    Additives in a clay mixture perform the same role as crushed stone in concrete. They are needed so that during drying and subsequent work with variable thermal loads, the surface of the furnace does not crack.

16. The perlite backfill on top also needs to be sealed with coating.
17. The front part of the oven is formed. To do this, lay out the outline of the stove using any suitable method (brick or stone masonry, sandbags, adobe). Inner part filled with crushed stone, and the top is given the desired shape using adobe mixture.
18. An outer casing made of a metal barrel is installed on the prepared base, orienting the container with the lower pipe towards the stove bench. The lower part of the container is sealed with clay.

    

    Installation of a casing - a metal barrel

19. Using a corrugated pipe, a channel is led to the firebox, which connects the firebox to the external atmosphere. If it is not installed, the stove will consume warm air from the room, which will be replaced by cold masses coming from outside. On the side of the firebox, the channel will need to be closed as soon as the firewood is completely burned out. This will not allow air from the street to penetrate into the heat exchange channels.

    

    Duct for supplying air from outside the building

20. To check the operation of the rocket stove, the first kindling is carried out, during which they make sure that the gases freely exit into the horizontal chimney.
21. Heat exchanger pipes are connected to the lower pipe, which are installed on a base formed of red brick.
22. The chimney is being installed. All connections of parts of horizontal and vertical channels are sealed using asbestos cord and fire-resistant coating.
23. Using the same method as in the manufacture of the stove body, give the required configuration to the stove bench.

    

    Fully formed oven with bench

24. The barrel can be completely covered with adobe, leaving only the horizontal platform open, which is convenient to use for heating food.
25. The chimney brought outside is equipped with a condensate and tar trap, and the upper cut is protected from precipitation using a cap.

    

    The outer part of the chimney is equipped with a liquid trap

Tests of the rocket furnace are carried out only after the adobe coating has completely dried. Otherwise, the decorative coating may crack.

View of the finished rocket stove with a stove bench

For safe operation of a rocket stove, the room must be equipped with carbon monoxide sensors.

Modernization of rocket heat generator

To expand the scope of application of reactive heating stoves, they are being modified, increasing the convenience and versatility of the design. In mobile structures, the platform intended for cooking is often replaced with a full-fledged stove. like this hob It is convenient to use in your own backyard for economic purposes - for preparing food for pets or during the period of preserving food for the winter. A special feature of this type of rocket furnace is a wide and flat horizontal channel into which hot gases from the nozzle are directed. Passing under the surface of the stove, they heat it red-hot, after which they go into the vertical chimney. Comfortable legs give the structure stability, and the original shape allows the unit to be used as a stand or table when it is not in use for its intended purpose.

A jet stove with a stove is a necessary thing in a suburban area

A liquid heat exchanger cannot be installed in the flame tube of a jet furnace, but this does not mean that it cannot be used as a water heat generator heating system. To do this, the “rocket” is equipped with a kind of circuit of radiator plates, which create a kind of labyrinth in the afterburning zone. Thanks to their heating, heat is removed from the afterburning chamber to the water jacket. The efficiency of the unit depends on the area and heat capacity of the plates, so they are made in the form of massive metal strips with an area of ​​up to ¾ of the cross-section of the fire channel. It must be said that such a heat exchanger is best used to produce hot water using the rocket stove itself in the traditional way.

Diagram of a rocket unit equipped with a water circuit

The rocket stove with a convector has an original design. To increase heat transfer, vertical tubes are mounted on the surface of the outer casing, performing the same role as the air channels of the buleryan. Cold air is trapped at the bottom of the tube heat exchangers and is heated as it moves upward. This ensures forced convection, which further increases the thermal efficiency of the installation.

Rocket heat generator casing equipped with a convector

Features of using reactive furnaces

Being a long-burning system, the rocket stove requires preheating before use. As a rule, in mobile installations no one complies with this requirement - they consume little fuel, and the potbelly stove itself is most often used on the principle of “it works, and that’s okay.” In stationary structures, warming up the furnace before starting is extremely important, since with a cold flame tube there can be no question of afterburning. The wood will burn without giving off heat, and the chimney will very quickly become covered with soot, tar and creosote.

The stove is heated using wood chips, paper or shavings, which are loaded into the firebox and set on fire. Reaching operating mode is judged by a humming sound in the heat channel. A loud sound indicates ineffective operation of the unit. As soon as the hum begins to subside, you need to start adding the main fuel. The vent should be completely open for the first 10–15 minutes. Then the air supply is reduced, focusing on the sound of the stove - it should “rustle” or “whisper”. After the wood burns out, the air duct of the firebox is covered to prevent heat from escaping from the room. Once every 2-3 days, ash is removed using a metal scoop and poker.

Maintenance of the jet stove is carried out no more than once a season. To do this, open the ash pan door, through which the remaining soot is removed. If necessary, clean the smoke channel using the hatch of its trap. I must say that correct operation jet heater never leads to smoke in the room. All that is required of the owner is to follow the recommendations for using the “rocket” and not neglect safety rules.

DIY rocket stove: subtleties and nuances of construction (video)

Unique technical characteristics, almost zero cost and availability of materials for construction cover all the disadvantages of the jet furnace. If you wish, you can build a full-fledged heating device over the weekend, including arranging a comfortable couch. “Rocket” is also convenient because it does not require highly qualified stove maker, but external design allows the implementation of even the most unusual design concept.