How to make a rocket stove. Rocket stove: do-it-yourself rocket, drawings and video, long-burning rocket stove, for heating. Construction of a brick rocket stove

Content

Portable and stationary rocket stoves (jet stoves) have proven themselves to be practical, energy-efficient devices. Heating and cooking units got their name because of the characteristic roar, reminiscent of the sound of a jet engine - it is heard when excess air enters the firebox. Operating in standard operating mode, the stove does not disturb the acoustic comfort in the room.

Homemade rocket stoves

Features of the reaction furnace

The first furnace of this type was created for use in field conditions - a unit was needed for instant cooking food and heating, and designed for operation in conditions of fuel shortage. The developers managed to find a solution that made it possible to produce a compact solid fuel stove with high efficiency.

Further modifications of the unit led to the invention of a stationary stove with a heated bench. Unlike the usual Russian stove, rocket stoves are not bulky and are easier to make yourself. The heat generator is capable of operating on one load of fuel for about 6 hours, while the stationary structure, for the construction of which adobe plaster is used, releases the accumulated heat within half a day after the firewood burns out.

The stationary design of the rocket stove with a stove bench retains heat for about 6 hours on one tab

Advantages of the design

The jet furnace is in growing demand because it is a non-volatile heat source that:

• easy to install - a primitive version of a rocket stove can be assembled from scrap materials in half an hour;
• works effectively even on fuel with low calorific value - damp firewood, thin branches, wood chips, bark, etc.;
• provides heating and allows you to cook food;
• completely burns fuel with afterburning wood gas, which minimizes the risk of carbon monoxide entering the room.

The design of the stove makes it possible to use it in the house without fear of causing damage to the thoughtful interior - the body of the stationary unit can be almost completely hidden in an attractive “shell”, which will serve as a heat accumulator.

To understand how good efficiency is achieved when working on low-quality fuel, you need to understand the operating principles of a jet stove.

During thermal decomposition, solid organic fuel releases gaseous substances, which also decompose and ultimately turn into wood gas (a mixture of combustible and inert gases), which burns with high heat output.

In an ordinary solid fuel stove, the thermal efficiency of wood gas is practically not used, since the gaseous intermediate phase goes with the smoke into the chimney, where it cools and settles on the walls in the form of carbon deposits, which are heavy hydrocarbon compounds. The higher the humidity of solid fuel, the less wood gas is formed and the more soot on the walls of the chimney. Accordingly, the worse the stove heats.

A rocket-type furnace differs from conventional solid fuel units in that its design makes it possible to provide conditions under which a significant part of the intermediate gases does not evaporate, but turns into wood and is burned. This is achieved due to a horizontal heat-insulated channel, where gases move more slowly than in a vertical pipe, and a thermal insulator prevents cooling and turning into carbon deposits. As a result, even from raw fuel, significantly more thermal energy is extracted compared to combustion in a conventional furnace.

In complex models of reactive heating units, the operating principle of a long-burning furnace, where afterburning of pyrolysis gases is provided, is combined with design features classic brick ovens, in which heated air and gas circulate through internal channels. At the same time, such a rocket does not need additional blowing - the chimney creates the thrust in it, and the higher it is, the more intense the upward flow.

Despite the fact that rocket stoves are capable of squeezing maximum thermal energy from low-quality fuel, they demonstrate optimal efficiency indicators when using dry firewood.

Difficulties and disadvantages

The disadvantages include:

• manual control of the stove - fuel must be added regularly (the burning time of the filling depends on the configuration of the heater);
• some structural elements heat up to high temperatures and threaten to cause burns if they accidentally come into contact with the skin;
• It is not rational to use a rocket as a sauna stove, since it takes a long time to warm up the room.

The design of a jet stove looks extremely simple, but the invention of such a unit took a lot of time, since the key to effective operation is an accurate calculation so that the fuel combustion mode is optimally correlated with the traction force, etc.

Important! Rocket stoves are a heat engineering system that requires fine balancing. Failure to comply with the dimensions of the structure or errors in assembly, incorrect operating mode of the unit results in the stove roaring loudly during operation due to an unstable gas vortex in the chimney, requiring more fuel with low heat transfer and quickly becoming overgrown with soot.

The jet stove was invented in the USA, and the details of its construction are not disclosed - only corrected drawings are publicly available, based on which it is difficult to build a truly efficient heater.

Stove-bed at home

Models for outdoor and hiking use

For heating water and cooking food, jet stoves of the simplest modification, made of metal pipe or brick. They are easily made with your own hands for household needs.

To make a metal outdoor cooking stove, two pipes connected by an elbow at a right angle are enough. Legs made of reinforcing bars and a stand for dishes are welded to the structure (so that there is a gap between the bottom of the container and the cut of the pipe for smoke to escape).

Outdoor rocket stove made of pipes

This design can be improved by inserting another elbow with a pipe into the horizontal pipe, the height of which should be less than the chimney part - it will serve as a vertical firebox.

An even more functional modification is a camp stove made of a rectangular pipe with a firebox welded at an angle (it also serves as an ash pan). It is quite simple to make such a rocket oven with your own hands according to the drawings.

Robinson camping rocket stove with racks for dishes

To make the simplest outdoor reactive stove made of brick, you will need 5 minutes of time, 20 whole bricks and two more halves. Plus a metal stand for dishes.

Drawing of a Robinson stove with a stand for dishes

Such a stove must first be brought into operating mode - warm up the pipe, burning paper and wood chips, since gas stagnates in a cold pipe, preventing the fuel from burning well. When the pipe warms up, a powerful draft will appear when igniting the wood.

Jet stove made of bricks

Attention! A jet stove with a horizontal firebox has significant drawback- you need to constantly move burning wood. An inclined or vertical loading hopper, along the walls of which firewood slides down under its own weight, makes the unit more convenient to use.

Heating and cooking stoves for premises

To heat a greenhouse, garage or workshop, you can also use jet units, which can be easily and quickly installed with your own hands.

An analogue of a primitive furnace made of a metal pipe is built from brick on an earthen floor or a specially prepared foundation. A brick rocket furnace is mounted from solid ceramic or fireclay bricks using heat-resistant mortar.

Stationary brick oven on an earthen floor

A more efficient version of the heating rocket stove is made using a metal barrel, which serves as a casing and allows for insulation of the riser (the internal pipe that serves as the combustion chamber and chimney). Ash, sifted sand, and a mixture of sand and fireclay clay are used as insulation. Thermal insulation helps create conditions for the efficient production of wood gas, and the more it is released from the fuel, the higher the thermal output of a wood-burning stove. In addition, this thermal insulation material (it must be well sealed during installation) plays the role of a heat accumulator, capable of heating the air in the room for several hours after the firewood burns out.

Rocket stove made of 21 bricks

Improved heaters

A jet stove with a free gas outlet is not suitable for use as a heating stove, so it is supplemented with smoke exhaust channels and a heat exchanger. Drawings of a rocket stove of various designs help to clearly see the difference.

The operating principle of the improved unit is as follows:

• in order to maintain a high temperature in the vertical channel, which promotes the production of wood gas, it is thermally insulated with fire-resistant material, while a casing (from a barrel or a larger diameter pipe) with a hermetically sealed top is installed on top;
• the combustion chamber is equipped with a door, in the lower part there is a special channel for supplying secondary air - this air supply is required for afterburning wood gas (in simple models, air enters only through the firebox without a door);
• due to the installation of a chimney pipe in the lower part of the casing, the heated air does not escape directly into the atmosphere, but circulates through channels inside the furnace body, actively giving off heat;
• flue gases with the highest temperature enter the upper part of the housing, directly under the flat lid, which makes it possible to use it as a hob, and the already cooled flow rushes into the chimney pipe;
• The efficiency of the stove increases due to the intake of secondary air for combustion of pyrolysis gases, and the intensity of its supply is regulated by the system itself, since it depends on how quickly the flue gases cool in the upper part of the housing.

Advanced jet-type heating units include a long-burning rocket stove, which can be made from a gas cylinder, as well as a stove with a water jacket.

Jet heating unit from a propane cylinder

A rocket stove made from a gas cylinder is easy to make wood stove, which consumes fuel economically and effectively warms the room.

For its assembly it is used:

• empty propane cylinder (unit body);
• steel pipe with a diameter of 100 mm (for arranging a chimney and a vertical channel);
• steel profile pipe 150x150 mm (firebox and loading hopper are made);
• sheet steel 3 mm thick.

Making a stove from a gas cylinder requires the use of a welding machine. If you are planning to assemble such a rocket stove with your own hands, the drawings will help you accurately maintain the optimal dimensions of all structural elements.

Scheme of processes in a rocket furnace

At the preliminary stage of work, you should prepare a gas cylinder - turn off the valve, fill the container to the top with water to ensure that gas vapors that can explode from a spark are removed from the container. Then the top part is cut off along the seam. A hole is cut in the lower part of the resulting cylinder for the chimney, and in the bottom for the combustion chamber with an attached firebox. The vertical channel is brought out through a hole in the bottom, and a structure from a profile pipe is welded on the bottom side, according to the rocket drawing.

Attention! The sheet metal cover should be made removable and a non-flammable seal (asbestos cord) should be provided for reliable sealing. The flat lid is used as a cooking surface.

If you are installing a rocket stove from a gas cylinder yourself, you should pay close attention to the quality of the welds and check their tightness - air should not flow uncontrollably into the working stove. If everything is in order, you can install the chimney.

Important! The top of the chimney must be raised to a height of 4 meters relative to the level of the firebox in order to ensure the required draft intensity.

Such a home stove is regulated in power by the volume of fuel loading. The jet stove is put into operation by supplying air through the combustion chamber; this is regulated by the hopper lid. Next, secondary air is constantly supplied to the unit. This heating stove explodes at the end of the combustion process, since it is impossible to shut off the supply of secondary air, and soot deposits on the inner walls of the vertical channel. The casing cover is made removable so that it can be removed periodically.

Boiler unit

A long-burning boiler can be obtained by installing a water circuit on the chimney of a stove made from a gas cylinder or other materials, but according to the same scheme indicated above. However, heating the water in the circuit of such a unit will be inefficient, since the main part of the thermal energy is transferred to the air in the room and to the containers on the hob.

An effective version of a rocket stove made from a metal barrel

If you want to create a rocket boiler for water heating with high efficiency, you will have to sacrifice the cooking function. A do-it-yourself rocket stove according to the drawing presented below can be installed in a short time.

This will require:

• fireclay bricks and refractory masonry composition (for installing the base of the stove with a firebox);
• steel pipe with a diameter of 70 mm (for a vertical channel);
• steel barrel (for the casing);
• fireproof heat insulator;
• sheet steel 3 mm thick and a metal barrel (or pipe) of smaller diameter than the casing (for arranging a water jacket and smoke channels for heating the water circuit);
• steel pipe with a diameter of 100 mm for the chimney;
• container, pipes and connecting pipes for arranging a heat accumulator.

A rocket furnace with a water circuit is characterized by the fact that the thermal insulation of the vertical channel provides an optimal combustion mode for pyrolysis gases, while all the heated air enters the “coil” with a water jacket and releases the main part of the thermal energy there, heating the coolant.

Rocket stove with water circuit

The heat accumulator will continue to supply heated coolant to the heating circuit even after the furnace itself has cooled down. The container with water is equipped with a thick layer of insulation.

Heating unit with bench

A rocket stove with a stove bench is a device that can create a comfortable environment in one room. Such a unit cannot be used to heat several rooms, let alone the entire house.

Arranging such a long-burning unit with your own hands requires precise calculations - its power and the maximum permissible length of the hog on which the stove bed is located depend on the size of the stove body. It is also important to select the correct pipe cross-section for installation of the structure. Mistakes will result in the jet furnace becoming overgrown with soot in a short time or roaring loudly during operation due to turbulence in gas flows.

Design of a stove with a stove bench

Dimensions and proportions of the structure

To build a rocket stove with your own hands, you need to prepare detailed drawings, indicating the dimensions of all elements. At the project preparation stage, calculations are made based on the basic values ​​to which all others are tied.

Basic calculated values ​​are:

• D – diameter of the drum (furnace body);
• S – area of ​​internal cross section drum

Calculations of design parameters are carried out taking into account that:

1. The drum height (H) ranges from 1.5 to 2 D.
2. The coating of the drum is carried out at 2/3 N (if its edge is planned to be shaped, then 2/3 of the height should be the average).
3. The thickness of the coating layer on the drum is 1/3 D.
4. The internal cross-sectional area of ​​the vertical channel (riser) is 4.5-6.5% of S, the optimal value is in the range of 5-6%.
5. The height of the vertical channel is the maximum, as far as the furnace design allows, but the gap between the upper edge of the riser and the drum cover must be at least 70 mm for normal circulation of flue gases.
6. The length of the flame pipe (fire duct) must be equal to the height of the vertical channel.
7. The cross-sectional area of ​​the fire pipeline is equal to the corresponding indicator of the riser. Moreover, it is recommended to use a profile pipe for the fire pipeline square section, in this case the oven operates more stable.
8. The cross-sectional area of ​​the blower is ½ of the cross-sectional area of ​​the firebox and riser. For stability and smooth adjustment of the furnace mode, a rectangular profile pipe with an aspect ratio of 2:1 is used, which is laid flat.
9. The volume of the secondary ash pan depends on the volume of the drum minus the volume of the riser. For a stove from a barrel - 5%, for a stove from a gas cylinder - 10%. For containers of intermediate volume, it is calculated according to linear interpolation.
10. The cross-sectional area of ​​the external chimney is 1.5-2 S.
11. The adobe cushion under the external chimney should be 50-70 mm thick - if the channel is made of a round pipe, the counting is from the lowest point. The thickness of the cushion under the chimney is halved if the bed is mounted on wooden floors.
12. The thickness of the coating layer of the stove bench above the chimney duct is 0.25 D if the drum is from a 600 mm barrel, and 0.5 D if the drum is from a 300 mm cylinder. If you reduce the coating layer, the structure will cool faster after heating.
13. The height of the external chimney pipe should be at least 4 meters.
14. The length of the flue, on which the length of the stove depends: for a stove from a barrel - up to 6 m, for a stove from a cylinder - up to 4 m.

A long-burning rocket stove made from a 600 mm diameter barrel reaches a power of about 25 kW, and a heating rocket made from a 300 mm barrel reaches up to 15 kW. The power can be regulated only by the volume of fuel; such a stove does not have air regulation, since the additional flow disrupts the stove mode and provokes the release of gases into the room. Changing the position of the blower door regulates not the power, but the operating mode of the furnace.

Lining features

The quality of the riser's thermal insulation directly affects the efficiency of the heating unit. In our area, lightweight fireclay bricks ШЛ and river sand with an admixture of alumina are available for lining. The lining should have an external metal casing, otherwise the materials will quickly absorb carbon deposits and the furnace will roar during operation. The end of the lining is tightly covered with oven clay.

Proper execution linings

When using hewn fireclay bricks, the remaining cavities are filled with sand. If only sand is used for lining, it is sifted to remove large debris and covered in layers - each approximately 1/7 of the height of the pipe. Each layer is compacted tightly and sprinkled with water to form a crust. The backfill must be dried for a week, and then the end must be covered with a layer of oven clay. Then the construction of the rocket furnace with your own hands continues according to the drawings.

Heating unit options

Setting up a rocket stove from a gas cylinder can also be done if you create a heater with a stove bench. The design is somewhat different from the one discussed above.

The changes concern:

• flame tube length;
• presence of thermal insulation of the vertical channel;
• connecting a horizontal rather than vertical external chimney.

Rocket stove diagram

Note! The expanded part of the external chimney is the ash pit, into which there must be access for cleaning - a metal door sealed with non-combustible material.

Due to the fact that the chimney channel can be made long and curved, the stove can easily be given its original shape.

Option for making a stove-bed with original form

The adobe coating, which acts as a heat accumulator, is made from a mixture of fatty clay with sand and chopped straw.

Principles of starting a stove

Important! Continuous combustion jet furnaces are launched exclusively “on warm pipe».

Before loading standard fuel, kindle with paper, shavings, straw and other dry materials. lightweight materials, which are placed in an open ash pit. When the vertical channel warms up sufficiently, the hum of the furnace subsides or changes tone. This is a signal that you can add the main fuel; it will flare up from the booster.

A jet stove will not regulate itself, so the hopper lid of a small stove or the ash door of a stationary unit should be kept open until the standard fuel ignites and the stove hums. The door is closed, trying to reduce the sound to a “whisper”. When the sound of the stove increases again, close the door again a little more tightly. If the door slams shut, then lifting it can allow the fuel to burn normally.

A mobile rocket stove is a convenient travel option, undemanding in terms of fuel and economical. Stationary units, depending on the design and size, are used for heating residential and auxiliary premises.

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 perhaps more remarkable is the “jet furnace” a huge amount associated with it, at times completely absurd inventions. 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 motion), 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 - 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 air 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 along Central Asia without loss. 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, the survivors were content camping 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. Our master most often just from the sketch immediately understands how this thing works, but in the little things 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. Yes, even important points may be omitted, veiled or obviously 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 Muslim name, and his first lady will dig up a vegetable garden near the White House and begin growing 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

With the fact that the exact variety is not indicated here fire clay(fire clay) Our guys will figure it out. 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 main principle operation of its 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 a sealed chimney (Airtight Duct), external chimney(Exhaust Vent), and the oven is almost ready.

Note: the riser and the drum covering it look like a stove hood above an upward-extended 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 metal sheet on screws with 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. During the 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 on 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 a small stove 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: it is impossible to supply secondary air to the mouth of the riser of a large furnace through holes in the drum (which would increase the efficiency of the furnace). 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 it 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 it should be homemade rocket stove 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 view in the high riser locks the general smoke path tightly, strong wind the outside can suck the heat out of the bed 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 bungalow bench 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 according to 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 in 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, 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; the author of the design provides a removable drum cover for cleaning the riser. 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 the 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 a modern material - heat-resistant concrete, adjusting all the 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 get light steam, the sauna stove must immediately warm up the walls with thermal (IR) radiation, and then, 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 rocket stove designs still have more intuition than accurate calculation. 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

Among the variety of wood stoves special attention deserves such a thermal device as a homemade rocket stove. It is distinguished by its original design, which does not require expensive materials and components in its manufacture. Any person who has at least the slightest understanding of drawings and knows how to work with his hands can make such a stove. Our article should come to the aid of such home craftsmen, where we will talk about the design and operating principle of the rocket stove. Recommendations for its manufacture will also be given here. various materials.

Operating principle of a rocket furnace

Although the design of a rocket stove is quite simple, it successfully uses two operating principles borrowed from other types of solid fuel heating devices:

• the principle of afterburning wood gases released during combustion (pyrolysis);
• the principle of free flow of gases through the channels (without encouragement from the natural draft of the chimney).

Note. In the simplest rocket stoves for cooking, including portable ones, only the second principle operates, since favorable conditions are not created in them for the pyrolysis process to occur.

First, we will analyze the design of direct combustion rocket stoves, intended only for cooking food. Here the firebox is a short horizontal section of pipe, which then turns upward. The design is simple to the point of disgrace, as shown in the figure:

The fuel is placed in the pipe and ignited, resulting in an upward flow of hot gases, tending to rise along the vertical section and exit outside. Here, at the cut of the pipe, a container for food or water is installed. Of course, there is a gap between the pan and the pipe for combustion products to escape. This is achieved through various metal stands.

For reference. The above rocket stove device is one of the first. It is because of the upward-turned nozzle with a flame escaping from it that the device received the name rocket.

Since it is impossible to heat rooms with such a unit, the design of the heating rocket stove was supplemented with a heat exchange device and channels for removing flue gases. To maintain a high temperature in the vertical section of the pipe, it is insulated with any fire-resistant material. Next, for intensive heat extraction, the nozzle is covered from above with a cap, for example, a conventional metal barrel. At the bottom of the horizontal fire pipe there is a separate channel for supplying secondary air.

Now the principle of operation of a rocket furnace looks somewhat different. Firstly, at the end of the horizontal fire channel, afterburning of pyrolysis gases occurs due to the supply of secondary air. Secondly, combustion products that have a high temperature accumulate under the top of the bell (barrel), creating some excess pressure. As heat is transferred outward through the metal walls, these gases cool and flow downward.

Since the cooling gases are supported from below by a new hot flow, they cannot descend in the same way, but pass through the space between the walls of the pipe and the barrel, safely exiting into the chimney channel. The flow of processes is well reflected in the diagram of a rocket furnace:

So, thanks to pyrolysis, the efficiency of wood combustion increases, and the use of free flow of gases creates a self-regulating system that limits the flow of fresh air into the firebox. The air mixture is supplied as the combustion products cool under the hood, making room for its new portion. Excessive pressure of hot gases “pushes” the cooled part out, so the operation of the stove depends little on the presence of draft in the chimney.

Efficient heat extraction

The gases entering the chimney duct are still at a high temperature. It is not advisable to simply throw them outside; everyone will understand that the efficiency of such an installation will be too low. Taking advantage of the fact that the rocket stove literally pushes combustion products out, craftsmen have come up with 2 ways to extract heat:

• passing gases through channels arranged under the stove bench;
• installing a water circuit on the stove.

A rocket stove with a water circuit is made without a hood; the force of the upward flow of combustion products is used in a multi-pass heat exchanger made of metal. It is not recommended to introduce a coil of water into the gas flow; it will not last long due to the too high temperature. It would be more correct to make a water jacket with metal fins inside the flue, as shown in the diagram:

Another way is to lay horizontal chimney ducts out of brick directly along the floor surface and place a luxurious heated adobe bench on top, connecting a rocket-type stove to it. What is important here is the correct selection of the length of the channels so that the excess pressure is enough to overcome them, otherwise you will still have to take care of organizing natural draft.

Advantages and disadvantages

Homemade long-burning rocket stoves have many admirers, and for the following reasons:

• simplicity and low cost of installation: to build such a thermal device, you do not need to incur large expenses for the purchase of expensive materials, fixtures and fittings. Minimal experience in the furnace business is also required;
• self-regulation and undemandingness to the natural draft of the chimney;
• The efficiency of the rocket furnace is a variable value and largely depends on the design, the main thing is to extract as much thermal energy as possible from the flue gases;
• fuel can be added on the fly.

Despite the attractiveness and simplicity of the unit, heating with a rocket stove has its negative aspects. It is a mistake to think that you can shove firewood of any quality into the firebox. Wet wood will not provide the required temperature in the chamber, and the pyrolysis process will not proceed. In the worst case scenario, smoke from the furnace can pour into the room. Also, the “rocket” requires constant supervision, especially in terms of fire safety.

Self-made rocket stoves are unsuitable for a bathhouse, since they give off relatively little heat in the infrared range, which is very important for a steam room. The surfaces of the stove that emit heat have too small an area and it will not be possible to heat the bathhouse properly.

For reference. A factory-made metal Robinson rocket stove is often used as a portable heat source. The craftsmen were not at a loss here either and quickly modernized this product, making the same thing, only with a grate.

Stove from a cylinder

This is one of the simplest options; to implement it, you can use the drawing below. A propane cylinder with a diameter of 300 mm will serve as an excellent cap, and a steel pipe measuring 150 mm will play the role of a firebox and loading hopper. The internal vertical channel is made of a pipe with a diameter of 70 mm, and the chimney is 100 mm.

The structure is completely welded, the pipes are cut to the required length, and the upper part of the cylinder is cut off. Then the parts are welded according to the drawings, only the opening between the vertical pipes with a diameter of 70 and 150 mm is filled with bulk thermal insulation material. This role can be perlite or vermiculite, or, in extreme cases, ordinary sand.

If there is an opportunity and desire to make a more powerful rocket stove, then a standard 200 liter barrel is used as a hood, then the dimensions of all parts also increase. The working inner pipe has a diameter of 129 mm (or a profile 120 x 120 mm), and the outer one has a size of 450 mm. It is difficult to find a pipe of this diameter, so usually they find another barrel of smaller capacity and cut off the bottom of it.

The entire assembled rocket stove made from a gas cylinder is not very heavy, so there is no need to build a massive foundation for it. When the unit is placed on the floor, the legs are welded to it, and if a bench is subsequently planned, the structure will have to be coated with a refractory compound, and then the external lining will be done. Then basalt cardboard and a sheet of roofing iron are laid on the floor below.

Brick oven

In terms of its design, a brick rocket stove is not much different from a metal one, but requires a lot of labor. The difference is that all the fire channels of the unit are made of fireclay bricks, and the cap is made from the same barrel.

It is recommended to lower the entire structure, except for the protruding cap, below floor level, for which a shallow hole is dug. Its bottom is compacted, and then a small concrete foundation 100 mm thick is poured over the formwork. After it hardens, they begin laying, using a solution of refractory clay. After finishing the laying and hardening of the solution, the hole is filled up, and an iron barrel without a bottom is placed on top of the fire channel, the cavity between it and the brick is filled with insulation.

The end of the structure is coated with the same solution, and then the largest barrel - a cap - is put on top. A chimney pipe is welded to its lower part; drawings of a rocket stove are used to clarify all dimensions.

Conclusion

With all its advantages, a home-made rocket stove cannot serve as a full-fledged heat source for heating an entire house. It makes sense to start such construction when it is necessary to organize heating small dacha or other similar building, especially since the “rocket” is not afraid of periodic work.

A rocket stove is a popular option when it comes to creating a do-it-yourself unit that can heat a room or act as a kind of stove in camping conditions. Drawings and diagrams of such a design should be available to people who love tourism.

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Creating a stove with your own hands is not difficult - it will take a little time, suitable tools, materials resistant to open fire and strong heat. Such a stove has several features and differences that make the stove an advantageous option for manufacturing.

A stationary camping rocket stove is installed both indoors (cottages, country houses) along the wall, and on a special platform, including on open space. Suitable for high-quality heating of a room with an area of ​​45-50 m2 (the presence/absence of partitions, walls, separate rooms, ceiling heights is taken into account).

About the design

The Robinson rocket stove consists of the following elements:

• Firebox.
• Pipe for removing generated smoke.

The design feature is that the fuel bunker is located not only vertically, but also horizontally, at an angle. The method of placement depends on the desire of the person, the features of the structure in which the finished stove will be installed.

This is what a rocket stove made from a pipe looks like

An option can also be used in which the fuel bunker will be located between the chimney and two elements of a horizontal pipe section. This is done in order to lengthen the surface heated during fuel combustion, thereby increasing the efficiency and time of warming up the room.

Conventional schemes for creating furnaces have:

• A firebox located vertically and connected to the chimney by a piece of pipe (its length can be different). The area connecting the elements is used for cooking (hob).
• A firebox located directly next to the pipe (the diagram is used in the case when the stove must perform the function of a heating unit).
• A firebox fixed at an angle to the pipe (for ease of loading fuel into a special compartment).

The stove can have two fireboxes at once. A special feature is their location on the sides of the structure in a vertical position. Pipes must have a large cross-sectional size. The purpose of the oven is to heat a container with liquid, which is placed on a special stand (this option is used to supply hot water).

Design options

General operating principle

The operating principle of all types of rocket designs is approximately the same:

• Solid fuel (firewood) is placed in the firebox.
• Ignition is in progress.
• When heated by flame and combustion, gases are produced.
• Their movement begins along the vertical section of the pipe.
• The supply is provided by a special channel through which “secondary air”, which is already heated, quickly moves.
• Heated gases rise to the base of the pipe.

The basic operating principle is similar to pyrolysis boilers. As a result, at the outlet of the furnace, the maximum possible temperature is reached in the upper part of the structure. It is used for heating, heating water, and cooking. For convenience, you can make a special platform for placing containers by attaching it to the top of the pipe.

A big and significant advantage for the user of a rocket stove is its efficiency - firewood, as well as other types of solid fuel, are consumed little, the efficiency is high (about 65%). In order to improve the quality of functioning, it is enough to throw sawdust, paper, branches or dry grass into the firebox.

The simplest version of a rocket stove

A simple rocket-type camping stove is easy to make, saves time and resources during use, and is compact in size and dimensions. All work will require you to spend 2-3 hours with the preparation of tools and materials, which is very convenient when camping or in a summer cottage.

A design feature that needs to be taken into account is that the lower part of the unit, which acts as the bottom of the fuel chamber (grid), must be made movable. This is done to facilitate the process of laying firewood and loading it into the combustion bunker.

If wood chips are used, the retractable structural element is convenient stand during the process of adding fuel to the furnace. Additionally, the moving part greatly facilitates the process of cleaning the unit from ash.

A simple rocket stove made from a pipe

Preparation of materials

To make a rocket stove you will need to purchase:

• Pipe with a square cross-section (15 cm×15cm×3, 40.5 cm) – 1 pc.
• The pipe is also square in shape (it is optimal to choose 15 cm × 15 cm × 3, 30 cm) – 1 pc.
• Steel strip (recommended dimensions 30 cm × 5 cm × 3 mm) – you need to buy 4 pieces of such elements.
• Another option for steel strips (with ideal parameters for work: 14 cm × 5 cm × 3 mm) – 2 pcs.
• A grate, also made of good metal (steel) (choose dimensions 30cm×14cm) – 1 piece.

Additionally, you will need to buy a steel rod (3:5 mm) - 2.5 meters in order to make the grate yourself if desired. A high-quality Robinson oven with your own hands means minimal financial investment, a little attention and time.

Tools

To carry out all the necessary work you will need:

• Bulgarian.
• Welding.
• Metal scissors.

Drawing

Work is carried out according to the diagram and drawing indicated below:

Drawing of the simplest rocket furnace made from a profile pipe

Manufacturing instructions

All creation work heating device must be carried out in stages. The guide to action consists of several steps that must be followed sequentially:

• Square pipes must be cut into pieces of the size required according to the drawing.
• Make markings on them, taking into account that one of their edges will need to be cut (the cut angle is 45 degrees). The work is carried out using a grinder.
• The resulting pipes will need to be carefully welded - the result should be a structure shaped like a boot.

When making a Robinson oven with your own hands and using drawings, it is important to follow the recommendations for the size of the parts contained there. The next steps will be:

• Cuts are made (on top of the pipe or on its sides) - the dimensions are 20 mm deep and 3.5 mm wide (a stand for installing containers will be installed in them).
• Steel strip (which has parameters 30cm×5cm×3mm), 1 piece purchased, must be cut exactly in half.
• Mark the second remaining strip of steel (also with parameters 30cm×5cm×3mm) exactly in the middle.
• To ensure high-quality completion of all stages of work, weld elements on both sides of the cut strip to it (you should get a cross-shaped shape).
• Steel strips (dimensions to be chosen are 30cm × 5cm × 3 mm) - the remaining 2 pieces and the remaining 14 cm long sections are welded into a frame that will be retractable.
• The elements are welded not side by side, but overlapping.

On top of the finished frame, using a spot welding machine, a finished grille (purchased additionally/specially) or parts of a good steel rod cut to the required length are attached. The distance at which the parts are attached is 1 cm. Then, a stand is installed on top of the pipe, and the grate is pushed into the combustion hopper. The main work on the production of the furnace can be considered completed.

The stage of verification and test behavior begins. You need to put some solid fuel in the firebox and light the stove; if no problems are identified in its operation, you need to wait for all structural elements to cool completely. Finally, you can paint the stove to protect the parts from corrosion. For this, heat-resistant paint is used. You can increase the operating comfort by welding a handle to the combustion chamber door.

Robinson oven

Convenient and functional, the Robinson Rocket Stove is an excellent option for use on a hike or in the country. It is also not difficult to make it using drawings and diagrams. With your own hands you can easily create a unit that will be very similar to the factory one.

Robinson oven

Materials

To make a high-quality heating product on your own, you will need to purchase the following materials:

• Steel sheet (for making the body of the combustion bunker measuring 15 cm × 10 cm × 30 cm) – 1 piece, thickness 3 mm.
• Plates made of high-quality steel (at least 3 mm), the material parameters are 30 cm × 15 cm - you will need to take 2 of them.
• Strong steel plates with dimensions of 10 cm × 30 cm - according to the classic version of the project, 2 pieces will be required.
• Plates, also made of good steel, 10cm×15cm – 1 piece.
• Metal plate parameters: 15cm×20cm×3mm – 1 piece (for making a blower).
• Pipe with a diameter of 10 cm (height 60 cm) – 1 piece (metal).
• Sections from reinforcement with a diameter of 7 or 8 mm - 1.2 meters (required for the manufacture of the grate).
• Rings with a diameter of at least 3 cm – 3 pcs.
• Vertical riser (10 cm) – 1 pc.
• Ring with a diameter of 11 cm – 1 pc.
• Nuts (part value d13 is selected) – 3 pieces.
• Line segment steel pipe with thread - you need 3 of them for work.

Tools

• Bulgarian.
• Welding.
• Marker.
• Metal scissors.

You should also have safety glasses and gloves.

Drawing

The Robinson camp stove is assembled with your own hands according to the following drawing:

Drawing of the Robinson stove

Step-by-step instruction

All basic work will require accuracy and attention, but will not take much time - about 3 hours with preparation. Basic actions involve the following steps:

• Preparing a plate that will separate the firebox from the ashpit in the finished structure - you will need to weld pieces of reinforcement to it (a distance of 1 cm from each element) - the result will be a grate.
• For convenience, a grate is attached to the plate available among the materials for manufacturing, after which, using a welding machine, you need to securely attach the resulting element to the side and rear walls of the future firebox. Feature of the work: before starting welding, you need to step back 30 cm from the bottom along the edge.
• The next step in the work is welding corner elements connections of the rear and side walls of the combustion chamber.
• Then the bottom of the chamber is welded.

After these steps, you should move on to the final steps. Here actions such as attaching nuts are performed, which are necessary for the stove to stand stably. Next, if desired, legs are attached to them. Then the steps are:

• The firebox cover, if provided for by the selected drawing option, is attached to the body (welding is used).
• The next stage is marking the pipe (for this purpose you will need to use a bright metal marker).
• Afterwards, a cut is made at an angle of 30 0 (a regular oval is obtained according to the outline).
• Each of the required pipes from the set of materials must be placed with an oval-shaped hole exactly in the middle of the roof of the structure.
• You will need to circle the pipe (with a marker).
• The resulting drawing is needed in order to cut a hole along its contour (the work is carried out using welding, the voltage may need to be increased).
• Then a pipe is welded into the resulting hole; it must be positioned vertically according to the diagram.

At the end, the legs are attached (optional), and the first test run is carried out (with a minimum of solid fuel element). If you want to paint the structure, then before doing this you need to completely cool the entire structure.

Ready-made homemade Robinson stove

Design improvement

A convenient DIY camp stove, Robinson, assembled according to the diagram, can be improved.

The first thing you can do is to weld a door with a handle to the main structure in order to be able to control the amount of heat generated or the amount of firewood in the firebox. It will open not to the side, but upward.

The best option is to manufacture a damper that will open in several positions:

• down or left;
• then to the right.

Such a damper must be installed in the corners welded in advance to the walls; the dimensions are chosen 1X1 cm or, as an option for an increase -1.5 cmX1.5 cm.

Additional ways to improve the Robinson furnace - increasing the thickness of the steel for the combustion chamber with 3 to 5 mm.

For an area where labor runs vertically, you can use a square rather than an oval hole.

The stand and legs can be created from various materials, using the most convenient options.

The last thing you can do is weld a wide metal plate to the firebox or attach metal corners to the pipe to place a water container on them. This will create a rocket stove with a hob.

Rocket stove with hob

Stove "Antoshka"

This popular option for a tourist-camping type stove will require a little more time to self-production. The Antoshka model rocket stove is distinguished by its convenient design. A special feature of this type of furnace is the presence of an additional plane heated during operation of the unit.

It is also a stand for a container (hob) and a room heating amplifier. Consequently, the Antoshka stove can be used to provide hot water to a country house or a tourist camp.

Stove "Antoshka"

Materials

In order to make a stove yourself, you need to purchase the following set of materials:

• Square pipes (with material parameters 15 cm×15cm×3 mm. The length is also taken into account, which in this option should be 40.5 cm) - 1 piece and (15cm×15cm×3 mm, also the length of the element is 18 cm) - 1 piece and (10 cm×10cm×3 mm, with product length 60.5 cm) – 1 piece.
• Metal/steel plate (30cm×15cm×3mm) – 1 pc.
• The plate is also made of good, heat-resistant metal (the parameters should be as follows - 15cm × 15cm × 3 mm) - 1 pc.
• High-quality metal corner (5cm×5cm×3, length 30 cm) – 1 pc.
• Larger metal corner (5cm×5cm×3, length 40.5 cm) – 1 pc.

Additionally, you will need reinforcement/rod with a diameter of 8 mm, the length of the material in this version is 30 cm - you will need to purchase 4 such rods.

To make a grate with your own efforts, you will need reinforcement with a diameter of 8 mm, its length is 17 cm - 8 pieces. It is important not to forget to purchase triangular metal gussets that will need to be used to install the hob; the steel in them should be 3 mm - 2 pieces.

Tools

To carry out all the necessary work you will need, as in the previous version:

• Bulgarian.
• Welding (for reliable fastening of all elements).
• Marker.
• Metal scissors (for working with small elements).

You should also have safety glasses and gloves.

Manufacturing stages

To make the Antoshka stove you will need to do:

• Mark the existing pipe in the materials (place it vertically).
• Then make neat cuts on it, making them at an angle of 30 0.
• In the back of the pipe intended for the firebox, cut a hole whose size is 12x10 cm.

Second part of the work:

• It is also important not to forget to cut a hole at the bottom of the element, the size of which will increase slightly and will be 15x15 cm according to the drawing.
• Next you will need to connect these two elements.
• The rear wall of the firebox must be welded with a plate made of fire-resistant and high-quality steel prepared in advance for this purpose.

Afterwards, pieces of metal rods need to be welded to the lower hole of the Robinson rocket stove variation from the outside. The distance at which the work is carried out is 1-1.2 cm. Further work involves the following actions:

• To manufacture such a part of the heating unit as the blower chamber (air intake), a piece measuring 18 cm is used, which is part of a square pipe. Without it, the operation of the oven as a whole is not allowed for safety reasons.
• You need to make a cut on it at an angle of 30 0 (in the end, the size of this part of the structure is 10 × 18 cm).

The resulting part should have a bottom and two walls. It is best to place it on stands - this will ensure comfort for subsequent work. They are made from metal corners and attached by welding to the bottom of the structure.

• The firebox of the future furnace (upper hole) - the pipe included in the materials package is welded to it or otherwise attached (if there is no welding). It is important to mount it in a strictly vertical position. It is important to remember here that maximum care must be taken.
• Triangular-shaped products made of metal (it’s better not to skimp on quality here) need to be placed on an edge, which will increase the stability of this part of the structure to create the necessary combination of elements.
• They are then welded/attached to the pipe and additionally to the top of the structure.
• The creation of the unit continues by welding a plate measuring 3 dm × 1.5 dm × 3 mm to the edge of the combustion hole, which is located at the top (in front of the master performing the work).

The final part of the creation: you need to weld corners to the top of the vertically located pipe - this will be a stand on which a container for cooking or heating food is installed. The reinforcement needs to be bent (90 0 - semicircle), the resulting corners are welded to the pipe on four sides at a distance of 30 cm from each other.

Conclusion

Robinson stove has various options for the manufacture of. This is not only a good option for heating small house or a tent camp on a camping trip, but also a real hob that can provide hot food. Additionally, using a homemade Robinson stove, which has a mount for a water container, you can provide hot water.

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In order for the reactive furnace to operate efficiently, the following rules must be observed when installing the structure:

1. The chimney must be at least twice as long as the horizontal or inclined section.
2. The length of the fuel compartment must coincide with the horizontal section. Typically the firebox is installed at an angle of 45°, although there are designs with an angle of 90°. But they are less convenient in terms of fuel loading.
3. The cross-section of the chimney should not be smaller than the fuel compartment itself.

Device

Robinson factory camping stoves are made from a profile pipe with a cross-section of 150×100 mm. Homemade structures are made of the same size. In this case, the bunker is made of a profile pipe, and the chimney is made of a round pipe. In order for there to be normal draft, the chimney pipe must have a diameter no less than the cross-section of the firebox.

For this size of the fuel compartment, a chimney no longer than 90 cm is allowed. But such dimensions make the unit inconvenient for transportation, so it is better to limit it to a minimum of 60 cm.

A steel rod is used for the legs. They are threaded, making the supports easy to install and remove. However, after using the jet stove many times, it becomes quite sooty, so the process of screwing the legs is not very pleasant. However, other options are also common, where a steel sheet is used to make the stand or non-removable legs are installed. But this makes the structure larger and more inconvenient for transportation.

In Robinson factory ovens there is no provision for air supply to the combustion zone, and they also do not have an adjustable lid that changes air access. This point can be corrected in homemade ovens. A plate is welded inside the bunker for flammable substances, at the bottom of which there is a grate. Fuel is placed on a flat element. Air enters the combustion zone through the grate, and a damper can be installed at the top of the firebox, with which the air supply will be regulated. It is made somewhat smaller than the firebox and should not completely block the hole, otherwise air will stop flowing into the compartment and the fire will go out.

This design of a reactive furnace provides a number of advantages:

• a small amount of solid fuel allows you to bring water to a boil in a short time, heat up food or cook simple dishes;
• Robinson is not afraid of the wind, so the fire does not go out;
• the jet stove is easy to install;
• the device does not smoke or smoke;
• factory models are made of high-quality metal and coated with heat-resistant paint that can withstand high temperatures;
• fuel does not burn out too quickly;
• the device allows you to dry firewood;
• the design is stable and easy to use;
• the rocket stove heats up quite quickly;
• maximum surface temperature reaches 900 °C;
• Thick steel (3.5 mm) ensures the durability of the device.

The price of the factory model is approximately 5 thousand rubles. But you can save money by making such a unit yourself. This task is doable if you have certain skills.

Manufacturing the Robinson stove

The simple design of the device allows you to make a rocket stove at home. The whole procedure will take only a few hours. It’s not difficult to find materials for the work, and you only need a few of them. The homemade unit is compact in size and easy to use.

The camp rocket stove is equipped with important detail, which greatly facilitates the maintenance of the unit. This metal plate with grill, located at the bottom of the firebox. As a rule, it is made retractable, which allows you to remove the grate, put firewood on it and install it back. A similar plate also serves as a stand for long wood chips. In addition, with the grill removed, it is easier to clean the fuel compartment.

To make a reactive furnace with your own hands, you must use the following materials :

• two square pipes 150x150x3 mm: one 45 cm long, the second 30 cm;
• 4 steel strips 300×50×3 mm;
• 2 steel strips 140×50×3 mm;
• metal grid 300×140 mm (it can be made from a rod of the same material with a diameter of 3-5 mm and a length of 2.5 m).

The Robinson camping stove manufacturing technology includes the following operations:

DIY Robinson factory model

Making a rocket stove similar to the one produced in factories is not a difficult task. There are not so many structural elements in this model:

As for the dish stand, its configuration is not fundamentally important for the operation of the device. Therefore, this element can be done differently. In this case, it is important to follow the rule that the stand should not block the chimney opening, so as not to disrupt the draft.

In the model under consideration, 3 rings are cut in half and welded to a metal rod.

This design is more complicated than the previous one in that the cross-section of the box is rectangular, and the chimney is round. Therefore, it is important to correctly perform the operations of connecting two parts into one device. Generally The production technology is as follows:

1. It all starts with making a plate with a grid that will divide the bunker into two parts. To do this, pieces of reinforcement are welded to the flat element in increments of 10 mm.
2. The resulting part must be welded to the rear and side walls of the bunker. The distance from the bottom edge to the plate with the grid should be 30-35 mm. The part must be attached using a welding machine parallel to the bottom edge.
3. Then you need to carefully weld the joints of the walls together.
4. The bottom is attached to the resulting structure, and nuts are attached to it.
5. The top plate is welded to the back and side walls.
6. A cut at an angle of 30° is marked on the pipe. The unnecessary part is cut off.
7. The end that has acquired the shape of an oval must be attached to the upper section of the hopper. In this case, the pipe is placed at the very bottom of the upper plate and equidistant from the side walls. This element is outlined with a marker, and a hole is cut according to the markings. To do this, you can use a welding machine or a metal cutting device.
8. Then you need to attach a pipe to the resulting hole. A stand is installed on top of it, and the legs are screwed into the nuts. Now the rocket stove can be tested. After this, it is covered with heat-resistant paint.

Manufacturing a modernized Robinson furnace

The model described in the previous section can be improved with a door that is installed on the fuel hopper. But if you make the sash on hinges, it will simply tilt upward, which will not allow you to adjust the draft. Such a part can only be in the “closed” or “open” position. It will be much more effective to use a damper that moves vertically or horizontally. To install it, you need to weld small corners measuring 10x10 mm or 15x15 mm onto the hopper.

In addition, the following options for modernizing the furnace are noted:

• the fuel hopper can be made of thicker steel, for example 5 mm;
• replace the round chimney pipe with a square one;
• for the stand, use a different design: as an option, take corners, balls or other elements that are at hand;
• change the stand for the camping rocket stove, for which a metal plate and a piece of reinforcement can be used to make a leg.

To make a modernized stove, you will need the following: materials:

1. Square pipe with a cross-section of 160×160 mm and a length of 400 mm. The firebox will be made from it.
2. Square pipe with a cross-section of 120×120 mm and a length of 600 mm. It is needed to make a chimney.
3. A five-millimeter sheet of steel and a piece of reinforcement with a diameter of 7-8 mm. The element separating the fuel compartment and the ash duct will be made from them. The size of the part should be 300×155 mm.
4. Steel sheet 350×180 mm. This material is necessary for the manufacture of a stove stand.
5. Steel sheet measuring 160×100 mm.

Production technology for this model of camping stove is not fundamentally different from creating similar structures:

1. A metal plate with a grate must be welded to the walls of the bunker.
2. Then the back of the container is attached, and the chimney is attached on top.
3. When the entire structure is ready, a metal stand is welded to it from below, and an additional support is made from a piece of reinforcement. You can also use part of the vertical pipe that remains after cutting.
4. Top on vertical pipe pieces of corners are welded to form a stand for dishes. Its height should be 40-50 mm.
5. The hole in the fuel tank must be closed with a hinged door or a flap inserted into the corners.
6. The finished product can be tested. If everything went well, the welds are cleaned and the reaction furnace is coated with heat-resistant paint. This will not only give the product a more attractive appearance, but will also protect the metal from corrosion.

Bottom line

We can conclude that any of the proposed models can be made quite easily at home. Finding the necessary materials will not be difficult. The work itself is not very difficult for someone who has used a welding machine more than once and has some experience working with metal. It only takes a few hours to make a rocket stove. And the resulting product will become a useful item for lovers of outdoor activities outside the city.

In addition, such a rocket stove will allow you to heat a small country house and will be a good alternative to a full-fledged heating system. The operating principle of the Robinson jet stove allows you to significantly save on fuel.