Dimensions of the rocket furnace. Making a jet furnace with your own hands

Simple stove options for heating a room, heating food and water are always popular, especially among home craftsmen who strive to make such units themselves. Similar designs include a rocket stove, which runs on wood and copes well with the tasks assigned to it, without requiring complex materials for manufacturing. Today we will take a closer look at the design of such an interesting heater, and also provide drawings and videos in order to make a rocket stove with your own hands.

Principle of operation

Before starting to manufacture the unit, you should consider in detail the principle of its operation. I would like to clarify right away that a rocket stove for the home has nothing to do with a jet engine and space flights. This name for the stove was given by the people due to its unusual appearance: the unit is very similar to an inverted rocket and makes a characteristic hum when operating.

A humming sound appears at the stove only under a certain operating mode, when too much is supplied to the firebox. a large number of oxygen. Please note that if your furnace hums too loudly or makes an unusual roar, this indicates improper, wasteful and ineffective operation. Correct operation of the rocket stove is accompanied by a barely audible rustling sound.

A portable rocket stove is often taken with you on a hike to heat food.

Depending on the scope of application, thermal units of this type can be divided into:

• Portable;
• Stationary.

The first ones are mainly used in traveling conditions, they are mobile, easy to transport and do not take up much space. free space. The second type of design is more capital. It is used for installation indoors, for heating a room or for heating food.

The principle of operation of a rocket stove can be most easily demonstrated using the example of the simplest tourist firebox “Robinson”. The design is an inverted pipe in the shape of the letter “L”.

Solid fuel (firewood, wood chips) is loaded into that part of the pipe that is in a horizontal position relative to the surface of the earth, then the fuel is ignited from the side of the vertical part of the pipe.

A thrust is created in the transition channel, which increases as the fuel warms up, and therefore for efficient work it is necessary to shut off the air supply from outside. If the air supply is not limited, the wood will burn out in vain, and no heat energy will ultimately be obtained.

Even the simplest rocket stove can heat water in a large container in a matter of minutes. If you produce correct insulation the top of the pipe, the device will be able to burn thick logs and heat a large room.

Types of rocket stoves

Depending on the type of design, rocket furnaces are divided into:

• A rocket stove with a water circuit (if properly equipped, it can replace a full-fledged solid fuel boiler);
• Rocket stove from a gas cylinder;
• Rocket stove "Flint - Master";
• A simple brick rocket stove with a stove bench;
• Hiking options from metal pipes.

General view of a rocket stove made from a gas cylinder

Advantages and disadvantages

The advantages of a rocket-type furnace include:

• High thermal output, which in some cases reaches 18 kW;
• High efficiency;
• Ultra-efficient operation, which is characterized by complete burnout of firewood, coals and soot loaded inside;
• Even waste from the woodworking industry (chips, leaves, twigs, branches, leaves, regardless of the degree of humidity) is suitable for combustion;
• Economical combustion and low wood consumption;
• High temperature regime at the outlet (heating a large container of water is carried out in a few minutes).

Along with the advantages, stoves of this type also have disadvantages:

• Installing a water heating coil reduces the thermal efficiency of the furnace;
• The continuous combustion cycle makes it impossible to install a rocket stove in garages and bathhouses;
• The small size of the firebox does not allow loading a large amount of fuel at once; to ensure long-term combustion, firewood is constantly added.

How to make a rocket stove with your own hands

Many people decide to install a rocket stove due to the ability to make it from available materials. Such a furnace does not require expensive materials and components, yet it stands out among others. wood stoves original design.

To make a stove, it is enough to have at least a little understanding of drawings and be able to work with your hands. Especially for home craftsmen, we will consider several options for making a rocket stove.

Walking from a profile pipe

This design is distinguished by its maximum simplicity, so it is with it that you can begin work on mastering the technology of constructing rocket furnaces. With the right approach, the entire production process will take no more than 3-4 hours.

The manufactured stove will have small overall dimensions and weight, which is why it is convenient to take it with you on hikes and fishing.

We will look at a slightly more complicated version of the rocket stove; the additional part will make the process much easier further use unit. This is a small metal plate with a grate that can be removed for convenient loading of firewood.

To make a stove, you need to prepare the following elements:

• Two pieces of square pipe measuring 15 by 15 cm (metal thickness - 3 mm). The length of one pipe is 45 cm, the other is 30 cm;
• 4 strips of steel 3 mm thick and measuring 30 by 5 cm;
• 2 steel strips 3 mm thick and measuring 14 by 5 cm.
• A metal grate measuring 30 by 14 cm. If you couldn’t purchase a grate of suitable sizes, you can make it yourself from steel rods.

A camping rocket stove is made in the form of a bent piece of pipe

Furnace production includes the following steps:

1. We mark two pipes for further cutting with a grinder at an angle of 45 degrees;
2. We connect the pipes together with cut sides and weld;
3. At the top of the vertical pipe, we make 4 cuts at the corners, insert prepared steel strips into them to form a cross, and weld the structure;
4. We make a frame for the retractable grille from the remaining steel strips, put the grille on the frame and weld it;
5. We check the oven for operability;
6. When the unit has cooled completely, paint it with heat-resistant paint to give it an attractive appearance.

The design can be slightly improved by welding a handle to the retractable grille.

Some craftsmen make a rocket stove right on the go from two tin cans from a soda bottle. This stove produces a minimal amount of heat, but it is quite enough to heat up dinner or a glass of water.

From a gas cylinder

To make a rocket stove from a gas cylinder, the diagram of which is shown in the figure, you will need:

• 80 cm of steel pipe with a diameter of 158 mm and a metal thickness of 4 mm;
• 150 cm of steel pipe with a diameter of 127 mm and a wall thickness of 3.4 mm;
• Profile pipe 100 cm long, 12 by 12 cm in size and 4 mm in wall thickness;
• 2 empty gas cylinders;
• Sheet metal;
• Steel bars;
• Material for thermal insulation;
• Metal pipe with a diameter of 12 cm for the chimney.

Diagram of a gas cylinder stove with dimensions

The production process includes the following stages:

1. We cut the profile pipe into two parts. One should have a length of 30 cm, the second - 35 cm. In the second pipe we cut out a hole for the firebox and for the vertical pipe of the future stove;
2. We cut the remaining piece of the profile pipe lengthwise and weld it to the firebox (it will serve as an opening for air supply);
3. We weld the firebox to the vertical pipe;
4. We make doors for the firebox and ash pan;
5. We check the functionality of the manufactured structure (primary chamber), wait for it to cool down;
6. Using a grinder, we cut out a hole in the bottom of the gas cylinder for the firebox. We weld a pipe with a diameter of 120 mm, which will serve as a chimney; in the lower part of the pipe we make a hole for cleaning the chimney;
7. We weld a piece of pipe of a slightly larger diameter to the chimney, and weld the firebox to the cylinder;
8. We fill the space formed in the cylinder between the pipe and the surface of the cylinder with perlite, which acts as a thermal insulator;
9. We cut off the bottom of the second cylinder with a grinder, weld a hole near the valve, the structure will act as a container for igniting gases;
10. We connect all parts of the stove together.

More detailed process Making a rocket stove from a gas cylinder is discussed in the video.

Video: rocket stove from a gas cylinder

From bricks

The diagram of the simplest rocket furnace is shown in the figure.

The simplest design involves 21 bricks

To build an improved structure, you will need about 20-30 bricks and dry clay.

We build a structure out of bricks, as in the picture. In appearance, it resembles a rocket that is preparing to launch.

Clay is used to give the structure strength and stability.

We check the stove for functionality, wait until the bricks have cooled, and coat them with prepared clay. The manufacturing process is completed. Once the clay is completely dry, the oven can be used.

Video: rocket oven made of twenty bricks

Long burning design

Most best option long-burning stoves - a stove with a stove bench. This design is perfect for heating a small room.

A long-burning rocket stove is an excellent option for heating your home

The manufacturing process involves the following steps:

1. The place where the firebox will subsequently be located is deepened into the ground by 10 cm, and a fire-resistant stone is placed in the resulting depression;
2. Formwork is installed along the perimeter of the masonry, and reinforcing mesh is laid on the bottom;
3. The lower part of the future working chamber is laid flush with the installed formwork, the structure is filled with concrete;
4. The constructed part is left for a day until the concrete hardens completely, then the base of the furnace and the combustion chamber are formed;
5. The walls of the future furnace gradually rise along the perimeter;
6. The lower channel of the rocket furnace is laid;
7. The constructed structure is sheathed with brick, except for the places where the firebox and raiser will be located;
8. A metal container (an iron barrel or a gas cylinder will do) is cut with a grinder on both sides, coated with a primer and painted with heat-resistant paint, and a pipe is cut into the lower part;
9. An outlet is welded to the chimney pipe, which will act as an ash pit;
10. A fire tube in the form of a square is laid out of brick;
11. In the resulting gap between metal container and thermal insulation material is filled with masonry;
12. The body of the future stove is formed, all brick surfaces are cleaned with clay, the future contour of the stove-bed is laid;
13. The performance of the furnace is checked;
14. All gaps are sealed, the shape of the bed is formed, and adobe is laid on top.

How to light a stove correctly

If no special preparation is required for firing mobile rocket stoves, then in order for the long-burning stove to work at the limit of its capabilities, it is necessary to preheat it. Such an event also helps reduce the degree of contamination of the chimney.

It is most convenient to heat the oven with paper sheets, wood chips and sawdust. The degree of heating is assessed by the resulting hum in the channel. Initially, the hum will be strong, this indicates high draft and low temperature; based on the degree of noise reduction, we can talk about an increase in the temperature in the firebox.

To heat the rocket stove, it is best to use small wood chips and sawdust.

As soon as the noise begins to decrease, the main fuel is loaded into the firebox. After about 15 minutes the damper begins to gradually close. The gap should be adjusted so that a barely audible rustling sound can be heard from the oven.

There are plenty of successful designs of rocket stoves online, and the authors are often guided more by intuition than by technical calculations. The main thing is to adhere to the “L-shaped” design, and then everything depends only on your imagination.

Be sure to check the operation of the oven at the preliminary stage.

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Let's say right away: rocket stove - 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 an excellent bed in your home without resorting to complex, expensive and bulky construction. Moreover, the very principle of the design of the rocket stove gives greater freedom to design and the manifestation of creative abilities, see fig.

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

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

Note: in fact, the rocket stove was so nicknamed because in the wrong combustion 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 furnace there is no conversion of energy types into each other, therefore it is not an engine. The stove simply distributes potential thermal energy appropriately 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 the propeller and compressor. In a ramjet engine (ramjet), the air supply to the combustion chamber is ensured by hypersonic speed pressure. A lot of experiments have been carried out on ramjet engines, but there have been no production aircraft with them, there are none, and there are no plans to do so, as ramjet engines are too capricious and unreliable.

Kan or not Kan?

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

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

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

However, there are no subtle thermal engineering wisdom in the can. This is an ordinary, only small, kitchen stove with a lower exit into the chimney, and most of the chimney itself is a long horizontal channel, a hog, on which a stove bench is located. Chimney, fire safety for the sake of – 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 keep sticking twigs into the oven, and our men disdained to cook food in cattle feces. But travelers of the past highly valued argal as a fuel; they collected it along the way and took it with them, carefully protecting it from getting wet. N. M. Przhevalsky in one of his letters stated that without argal he would not have been able to conduct his expeditions in Central Asia without losses. And the British, who disdained argal, had 1/3-1/4 of the detachments’ personnel returning to base. True, he was recruited from sepoys, Indian soldiers in English service, and pandits - spies recruited from the local population. One way or another, the highlight of the rocket stove is not at all the bed on the hog. To get to it, you will have to learn to think like an American: all the primary sources on the rocket furnace are from there, and utter speculation is generated only and only by misunderstanding.

How to deal with rockets?

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

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

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

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

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

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

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

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

And Russian breadth of soul is also a double-edged sword. 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 a Muslim name would be installed in the Oval Office, and his first lady would dig up a vegetable garden near the White House and begin to grow turnips there. Times is changing, as Bob Dylan once sang for a completely different reason...

Sources of misunderstandings

There is such a thing in technology - the square-cube law. Simply, when the size of something changes, its surface area changes by the square, and its volume changes by the cube. Most often this means changing general dimensions products based on 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 furnace design has a certain permissible range of its size and power, within which the specified parameters are ensured.

Why, for example, can’t it be made the size of a refrigerator and with a power somewhere around 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.

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

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

How was the rocket stove born?

So, without science fiction and futurology, the survivors needed stove for heating a home, operating 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 terms: 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 should 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?

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

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

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

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

Who are you, the Rocket Stove?

There is an unspoken rule in technology: if it seems that it is impossible to create a device according to the given requirements, then, smart guy, read your school textbooks. That is, go back to basics. In this case, to the basics of thermodynamics. Survivors do not suffer from sick pride; they turned to the basics. And they found the main operating principle of their furnace, which has no analogues in others: slow adiabatic afterburning of pyrolysis gases in a low 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.

Then things begin to become non-trivial. We need to warm up, and with good efficiency, large oven. 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 pipelines with rising current - riser. Purely American: correct and unclear.

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

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

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

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

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

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

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

Small rocket

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

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

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

Secondary air for afterburning wood gas in 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 a common property: You only need to run them 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 a homemade rocket stove should look like from the materials available to us. Here, too, we need to be careful: not everything that is at hand in America is what we have, and vice versa.

Of what?

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

The ash pit, bunker, firebox and riser will use pipes of 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, so the thermochemistry of the gases is gentle and the thickness of the steel is all metal parts, except for the gas pipeline in the bench - from 2 mm; the latter can be made from a thin-walled metal corrugated sheet, here the flue gases are already completely exhausted both in terms of chemistry and temperature.

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

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

Dimensions and proportions

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

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

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

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

Riser lining

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

From our available materials for heating engineering, they can be replaced with light fireclay bricks of the ShL brand and ordinary self-excavated bricks 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.

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

How to line with sand?

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

Balloon rocket

From the above, it is clear that it is more profitable to make a rocket stove: 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.

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

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.

Brick

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

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 sauna. To get light steam, you must immediately warm up the walls with thermal (IR) radiation, and immediately, or a little later, the air, by convection. To do this, the oven must be a compact source of infrared and a convection center. Convection from a rocket furnace is distributed, and it provides little IR at all; the very principle of its design excludes significant losses due to radiation.

In conclusion: to the rocket makers

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

A do-it-yourself rocket stove, the drawings of which most home craftsmen would probably like to have in their archives, can, in principle, be made even within one day, since its design is not at all complicated. If you have the skills to work with tools, read blueprints, and have the necessary materials, then making a simple stove of this type will not be difficult. It should be noted that it can be made from a variety of materials that are at hand, but much will depend on where the stove is planned to be installed. The rocket stove has a slightly different operating principle from other heating devices, and can be either stationary or portable.

Stationary rocket stoves are installed inside the house along the walls or on a designated area for cooking in the courtyard of the house. If the stove is installed indoors, it can heat a room up to 50 square meters. m.

Portable versions of the rocket stove are usually very small in size and can easily fit in the trunk of a car. Therefore, when going out, for example, to a picnic or to the dacha, such a stove will help you boil water and cook lunch. Moreover, the fuel consumption in the rocket stove is quite small; even dry branches, splinters or tufts of grass can be used as fuel.

The principle of operation of a rocket-type stove

Despite the simplicity of the design of the rocket stove, its design uses two operating principles, which the developers borrowed from other types of stoves operating on. So, for its effective operation, the following principles are taken:

• The principle of free circulation of gases released from fuel through the created stove channels, without the forced creation of chimney draft.
• The principle of afterburning pyrolysis gases released during fuel combustion in the mode of insufficient oxygen supply.

In the simplest designs of rocket stoves, which are used only for cooking, only the first principle of operation can operate, since it is quite difficult to create the necessary conditions for the flow of pyrolysis and organization of afterburning of gases.

To understand the designs and understand how they work, you need to consider some of them one by one.

The simplest design of a rocket stove

To begin with, it is worth considering the simplest design of a direct combustion rocket stove. As a rule, such devices are used only for heating water or for cooking, and exclusively outdoors. As can be seen from the figure below, these are two sections of pipe connected by a bend at a right angle.

The firebox for this furnace design is the horizontal part of the pipe, and fuel is placed in it. Often the firebox has a vertical loading - in this case, three elements are used to make the simplest stove - these are two pipes different heights, installed vertically and connected from below by a common horizontal channel. The lower pipe will serve as a firebox. To manufacture a stationary version of the simplest design scheme, it is often used, installed on a heat-resistant solution.

To achieve higher efficiency, the furnace was improved, and it appeared additional elements, for example, the pipe began to be installed in a housing, which increases the heating of the structure.

1 – outer metal body of the furnace.

2 – pipe – combustion chamber.

3 – a channel formed by a jumper under the fuel chamber and intended for the free passage of air into the combustion area.

4 – the space between the pipe (riser) and the body, densely filled with a heat-insulating composition, for example, ash.

The furnace is heated as follows. A light combustible material, such as paper, is first placed in the firebox, and when it flares up, wood chips or other main fuel are thrown into the fire. As a result of the intense combustion process, hot gases are formed, rising through the vertical channel of the pipe and escaping outside. A container for boiling water or cooking food is installed on the open section of the pipe.

An important condition for the intensity of fuel combustion is the creation of a gap between the pipe and the installed container. If its hole is completely blocked, then combustion inside the structure will stop, since there will be no draft that supplies air to the combustion area and lifts the heated gases upward. To avoid problems with this, a removable or stationary stand for the container is installed on the upper edge of the pipe.

This diagram shows a simple design with a door installed on the loading opening. And to create draft, a special channel is provided, which is formed by the lower wall of the combustion chamber and a plate welded at a distance of 7÷10 mm from it. Even if the firebox door is completely closed, the air supply will not stop. In this scheme, the second principle is already beginning to work - without active access of oxygen to the burning, the process of pyrolysis can begin, and the continuous supply of “secondary” air will contribute to the afterburning of the released gases. But for a full-fledged process, one more important condition is still missing - high-quality thermal insulation of the secondary combustion chamber, since the combustion process of gases requires certain temperature conditions.

1 – air channel in the combustion chamber, through which air is blown when the firebox door is closed;

2 - zone of the most active heat exchange;

3 – upward flow of hot gases.

Video: a version of the simplest rocket stove from an old cylinder

Improved rocket furnace design

The design, intended for both cooking and heating the room, is equipped not only with a combustion door and a second body, which serves as a good external heat exchanger, but also with an upper hob. Such a rocket stove can already be installed inside the house, and the chimney pipe from it is led outside. After such a modernization of the furnace, its efficiency increases significantly, since the device acquires many useful properties:

• Due to the second outer casing and insulating heat-resistant materials that thermally insulate the main pipe of the furnace (riser), hermetically sealing the upper part of the structure, the heated air maintains a high temperature for much longer.

• A channel for supplying secondary air was installed in the lower part of the housing, successfully providing the necessary air supply, for which simplest design an open firebox was used.
• The flue pipe in a closed design is not located at the top, as in a simple rocket stove, but at the lower rear part of the body. Thanks to this, the heated air does not go directly into the chimney, but is able to circulate through the internal channels of the device, heating, first of all, the hob, and then diverging inside the housing, ensuring its heating. In turn, the outer casing gives off heat to the air around it.

This diagram clearly shows the entire process of operation of the stove: in the fuel bunker (item 1), preliminary combustion of fuel (item 2) occurs in the insufficient air supply mode “A” - this is regulated by a damper (item 3). The resulting hot pyrolysis gases enter the end of the horizontal fire channel (item 5), where they are burned. This process takes place thanks to good thermal insulation and the continuous supply of “secondary” air “B” through a specially designed channel (item 4).

Next, hot air rushes into the internal pipe of the structure, called the riser (item 7), rises along it to the “ceiling” of the housing, which is the hob (item 10), providing its high-temperature heating. Then the gas flow passes through the space between the riser and the outer drum housing (item 6), heating the housing for further heat exchange with the air in the room. Then the gases go down and only after that they go into the chimney pipe (pos. 11).

In order to achieve maximum heat transfer from the fuel and provide the necessary conditions for complete combustion of pyrolysis gases, it is important to maintain the highest and most stable temperature in the riser channel (item 7). To do this, the riser pipe is enclosed in another pipe of a larger diameter - the shell (item 8 ), and the space between them is tightly packed with a heat-resistant mineral composition (item 9), which will serve as thermal insulation (a kind of lining). For these purposes, for example, a mixture of kiln masonry clay with fireclay sand (in a 1:1 ratio) can be used. Some craftsmen prefer to simply fill this space very tightly with sifted sand.

The design of this version of the rocket stove consists of the following components and elements:

• A lid-closable firebox with vertical fuel loading with a secondary air intake chamber located in its lower part.
• The furnace goes into a horizontally located fire channel, at the end of which the pyrolysis gas is burned.
• The hot gas flow rises through a vertical channel (riser) to the hermetically sealed “ceiling” of the housing, where it transfers part of the thermal energy to the horizontal plate - the hob. Then, under the pressure of hotter gases following, it diverges into heat exchange channels, giving off heat to the surfaces of the drum, and falls down.
• At the bottom of the stove there is an entrance to horizontal pipe channels that run under the entire surface of the stove bench. Moreover, in this space one, two or more turns of corrugated pipe can be laid in the form of a coil, through which hot air circulates, heating the bed. This heat exchange pipeline is connected at the end to a chimney pipe led outside through the wall of the house.

• It should be noted that if the bench is made of brick, the channels can also be laid out of this material, without the use of metal corrugated pipes.
• The heated stove and bench, releasing heat into the room, will themselves serve as a kind of “battery”, capable of heating an area of ​​up to 50 m².

The metal drum of the furnace can be made of a barrel, gas cylinder or other durable containers, and also made of brick. Usually the material is chosen by the craftsmen themselves according to their financial capabilities and ease of work.

A rocket stove with a brick bench looks neater and is somewhat easier to install than a clay version, but the cost of materials will be about the same.

Video: another original solution to increase the heating efficiency of a rocket furnace

We foldmade of brickrocket stovewith a bed

What is needed for the job?

The brick heating structure proposed for execution is designed on the principle of a rocket stove. The size of the structure with standard brick parameters (250 × 120 × 65 mm) will be 2540 × 1030 × 1620 mm.

Our task is to build such an original rocket stove with a warm bed out of brick

It should be noted that the design is divided into three parts:

• The oven itself – its size is 505×1620×580 mm;
• Firebox – 390×250×400 mm;
• Bed 1905×755×620 mm + 120 mm headrest.

To lay the stove you will need the following materials:

• Red brick – 435 pcs.;
• Blower door 140×140 mm – 1 pc.;
• Cleaning door 140×140 mm – 1 pc.;
• A fire door is desirable (250×120 mm - 1 piece), otherwise there is a risk of smoke in the room.
• Hob 505×580 mm – 1 pc.;
• Rear metal shelf panel 370×365 mm – 1 pc.;
• Asbestos sheet 2.5÷3 mm thick to create a gasket between metal elements and brick.
• Chimney pipe, 150 mm in diameter, with a 90˚ outlet.
• Clay and sand for mortar or a ready-made heat-resistant mixture. It should be noted here that for 100 bricks laid flat, with a joint width of 5 mm, 20 liters of mortar will be required.

The design of this rocket stove with vertical loading is quite simple, trouble-free and efficient in operation, but only if its masonry is done with high quality, in full accordance with the order.

If you have no experience as a mason or stove maker, but have a strong desire to install such a heating device yourself, you should play it safe and first lay the structure “dry”, without mortar. This process will help you figure out the location of the bricks in each row.

In addition, to ensure that the seams are the same width, it is recommended to prepare gauge wooden or plastic slats for masonry, which will be laid on the previous row before laying the next one. Once the solution has set, it will be easy to remove them.

Under the laying of such a stove it is necessary to have a flat and solid foundation. Despite the fact that the design is quite compact and its weight is not as great as, for example, a Russian stove, a floor laid with thin boards will not be suitable for its installation. In the case where the floor, although wooden, is very durable, before starting laying under the future stove, it is necessary to lay and secure a heat-resistant material, for example, asbestos 5 mm thick.

Order of a brick rocket stove with a stove bench:

Illustration	Brief description of the operation performed
	The first row is laid out solid, and the brick must lie in exact accordance with the pattern shown in the diagram - this will give strength to the entire base. For masonry you will need 62 red bricks. The diagram clearly shows the connection of all three sections of the furnace. The corners on the side bricks of the firebox facade are cut off or rounded - this way the structure will look neat.
	Second row. At this stage of the work, internal smoke exhaust channels are laid through which gases heated in the firebox will pass, giving off heat to the bricks of the stove bench. The channels connect to the combustion chamber, which also begins to form in this row. The first brick of the wall separating the two channels under the stove bench is cut diagonally - this “nook” will collect unburnt combustion products, and the cleaning door installed opposite the bevel will allow you to easily clean it. To lay a row you will need 44 bricks.
	On the second row, the doors of the blower and cleaning chambers are mounted, which are necessary for periodically tidying up the ash chamber and internal horizontal channels. The doors are secured with wire, which is twisted onto the ears of the cast iron elements and then inserted into the masonry seams.
	Third row. It almost completely repeats the configuration of the second row, but, of course, taking into account the laying in a bandage, and therefore it will also require 44 bricks.
	Fourth row. At this stage, the channels running inside the couch are blocked with a continuous layer of brick. A firebox opening is left, and a channel is formed that will heat the hob and discharge combustion products into the chimney pipe. In addition, a rotating horizontal channel is blocked from above, which removes heated air under the stove bench. To lay a row you need to prepare 59 bricks.
	Fifth row. The next stage is covering the bed with a second cross layer of brick. The smoke exhaust ducts and firebox also continue to be removed. 60 bricks are prepared for a row.
	Sixth row. The first row of the headrest of the couch is laid out, and the part of the stove on which the hob will be installed begins to rise. It still has smoke exhaust ducts. A row requires 17 bricks.
	Seventh row. The laying of the headrest is completed, for which bricks cut diagonally are used. The second row of the base under the hob rises. Laying will require 18 bricks.
	Eighth row. The furnace structure with three channels is being laid. You will need 14 bricks.
	The ninth and tenth rows are similar to the previous, eighth, they are laid out according to the same pattern, alternately, intertwined. 14 bricks are used for each row.
	11th row. Continuation of masonry according to the scheme. This row will take 13 bricks.
	12th row. At this stage, a hole is formed for installing the chimney pipe. The hole supplied under the stove is equipped with a brick cut obliquely for a smoother flow of heated air into the adjacent channel leading to the lower horizontal channels located in the stove bench. 11 bricks were used per row.
	13th row. A base for the slab is formed, and the central and side channels are combined. It is through this that hot air will flow under the stove, and then flow into the vertical channel leading under the stove bench. 10 bricks are laid.
	13th row. On the same row, the base for laying the hob is prepared. To do this, a heat-resistant material - asbestos - is laid around the perimeter of the space in which two vertical channels were combined.
	13th row. Then, a solid metal plate is laid on the asbestos pad. In this case, it is not recommended to install a hob with opening burners, since when they open, smoke may enter the room.
	14th row. The opening for the chimney pipe is closed and the wall separating it is raised. hob from the bedding area. Only 5 bricks are used for a row.
	15th row. This row raising the wall will also require 5 bricks.
	15th row. On the same row, in continuation of the back wall, a metal shelf is fixed next to the hob, which can be used as a cutting board. It is attached to brackets.
	15th row. The picture diagram shows well how a hob can be used. In this case, the pan is placed exactly on that section of the stove that will warm up first, since a hot air flow will pass under it.
	After completing all the work described in the order, a chimney pipe is built into the hole at the back of the stove, which is led out to the street.
	From the back, the design also looks quite neat, so it can be installed either near the wall or in the middle of the room. This stove is perfect for heating a country house. If you decorate the stove and chimney finishing materials, then the building can become an original addition, and a very functional one, for any private home. As you can see, the corner formed under the cutting shelf is very convenient for drying and storing firewood.
	To fully examine the structure, you need to see its projection from the end side.
	And the last picture clearly shows what should happen as a result of the work done, if you look at the stove from the side of the stove bench.

In conclusion, I would like to especially note that the design of a rocket furnace can be called one of the simplest and most accessible for self-made, compared to other heating devices. Therefore, if a similar goal is set - to acquire a stove in the house, but experience in similar work is clearly not enough, it is best to choose this option, since when building it, it is difficult to make a mistake in the configuration of its internal channels.

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

• • Operating principle of a long-burning rocket stove
  • DIY rocket stove: advantages, drawings, disadvantages
  • Blueprints jet furnace from a gas cylinder and other types
  • DIY drawings of the Flint stove and other models
  • DIY jet stove assembly for heating
  • Improved rocket furnace with water circuit
  • DIY rocket stove drawings (video)
  • Examples of a rocket stove (photo of ideas)

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

Types of long-burning rocket stoves:

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

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

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

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

A long-burning rocket stove is often used for heating garages and utility rooms

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

DIY rocket stove: advantages, drawings, disadvantages

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

Advantages of jet furnaces:

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

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

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

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

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

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

Types of reactive furnaces:

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

Drawings of a jet stove from a gas cylinder can be downloaded on the Internet or made by hand yourself

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

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

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

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

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

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

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

DIY drawings of the Flint stove and other models

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

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

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

Continuous combustion furnace diagram:

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

The Ognevo stove can be bought in a specialized store at a fairly reasonable price.

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

DIY jet stove assembly for heating

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

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

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

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

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

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

To properly assemble a jet stove with your own hands, you should first watch a training video and study the recommendations of specialists

Improved rocket furnace with water circuit

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

Materials required for equipping a stove with a water circuit:

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

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

DIY rocket stove drawings (video)

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

Examples of a rocket stove (photo of ideas)

Among the variety of wood-burning stoves, a heating device such as a homemade rocket stove deserves special attention. 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 from various materials will also be given here.

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 the portable type, only the second principle applies, since favorable conditions are not created for the pyrolysis process to occur in them.

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 most simple 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 the role of the firebox and loading hopper will play a role steel pipe size 150 mm. 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 heat-insulating 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. Working inner tube is accepted with a diameter of 129 mm (or profile 120 x 120 mm), and the outer one is 450 mm in size. 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 pit is filled in, and put on top of the fire channel iron barrel without a bottom, 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 the heating of a small dacha or other similar building, especially since the “rocket” is not afraid of periodic work.

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