To what temperature does the oven heat up in the bath

Product requirements

Liquid and solid fuels can be used for metal furnaces. Models that are assembled and manufactured independently are often not inferior in efficiency to factory stoves. There are certain requirements that a product must meet in order to be easy to use in a bath. Among them are:

• heat power adjustment;
• the presence of a heat accumulator;
• the ability to adjust traction;
• protection of surfaces with high temperatures.

The amount of heat given off by the stove should be regulated by the amount of fuel loaded. That is, the stove must have a certain power reserve. If this does not happen, then in winter she may not cope with her tasks in the bath. For baths, heaters are most often used. The embankment acts as a battery, which saves fuel and gives off heat for a long time. A water tank can also act as such a battery. The stove should be designed to facilitate convection to quickly heat the indoor air. It is important to think about the safety of the furnace design so that surfaces that are heated to high temperatures are protected by suitable shields.

ANSWER

This problem exists for everyone who uses a heat-insulated stove in a bath. The solution to the problem is to replace the oven. Naturally, for this you will have to shell out a certain amount of money, but the inconvenience will disappear. Other options can only be called a half-measure.

If, nevertheless, it is not possible to change the stove, then you will have to heat it, adhering to certain rules. Namely: after heating the oven to 100 degrees, try not to increase the temperature anymore, but keep the one that is. For this purpose, the fuel is placed in the furnace to a minimum, the ash pan is closed. In this way, ensure high efficiency for the furnace, a comfortable temperature in the room, and all this while saving fuel. The air temperature in about 40 minutes will reach the minimum when you can start steaming.

Should I use

Due to its design, the metal stove for the bath compares favorably with the stone counterpart. Among the positive aspects of the design are the following:

• compact dimensions;
• high heating rate;
• high efficiency;
• ease of installation;
• light weight;
• relatively low cost.

Compared to the stone version, the metal stove takes up little space, which will make it possible to design the room in the best way. The metal furnace requires less fuel and time to heat up, making it more cost effective. This leads to the high efficiency of such a stove. For the construction of a metal furnace, you will not need as strong a foundation as is needed for a brick one. In most cases, the project of a metal stove for a bath is cheaper than a stone analogue.

Such a stove also has its drawbacks, which include a high surface heating temperature. The consequence of this is the need to protect the surface of the walls as well as the floor from excessive temperatures. In addition, the high degree of infrared radiation can cause burns at a distance from the oven. This structure cools down much faster than a brick oven.

What to choose from

The differences between metal furnaces most often lie in size, design features and additional modules that may be present in them. Therefore, they can be conditionally divided into:

• vertical and horizontal;
• with or without water tank.

Vertical versions of sauna stoves take up less space, therefore, it is preferable to use. Horizontal ones heat up the air faster, since the length of the body has a large area of ​​contact with air. Some sauna stoves are designed with a water tank. Subsequently, it is mixed with cold and used in the washing room. By the location of the firebox, the following design options are distinguished:

• with a firebox in the steam room;
• with a firebox in the recreation room;
• with a firebox on the street.

When the firebox is located in the steam room, it becomes possible to load fuel without leaving the room. But this also has its disadvantages. One of them is the constant dirt from the wood, which mixes with moisture. The firewood in the steam room is damp and has a lower efficiency. The most convenient option is the design of a stove for a bath with loading firewood from the rest room, since it is easier to clean up, and those who are currently waiting for their turn can do the kindling. The last option for the location of the furnace for the stove is suitable for the smallest rooms and is relevant for use in the warm season. The design of a metal bath stove can also be:

• open;
• closed.

The first option is also called hot. Their peculiarity lies in the fact that they are installed as is, without the use of brickwork. The advantage of this option is rapid heating to high temperatures. But it is unsafe because it is easy to burn yourself on it. Closed furnace designs are also called cold. Most often they are lined with refractory bricks on all sides. This allows the wall temperature to be lowered. This design takes longer to heat up, but is safer. In addition, air ducts can be provided in it, which allow a significant amount of air to pass through, providing convection.

Note! There are also nuances in relation to the heater. It can also be closed or open. It is difficult to talk about the advantages and disadvantages of each. Most often this is a personal preference of the owner.

What does temperature affect?

To begin with, it is very important to figure out why this type of active recreation was originally invented at all and what is its main purpose. Understanding these things at first glance may seem like a repetition of obvious truths, but neglect of the basics is the main reason for the wrong choice of temperature during vaping.
The initial task of bath procedures is to create such conditions for the human body so that it actively begins to start natural cleansing processes. As a result of proper preparation for vaping, bringing the atmosphere of the steam room to the required level of heating the air and its humidity, as well as following a number of rules, the bath has such a significant healing effect on all systems of the body.

Such high efficiency on the one hand is an advantage of the bath, but on the other hand it becomes a serious disadvantage. Often, the steam room is used simply as another entertainment or a way to spend time with friends in an interesting way, and as a result, going to the bath turns into a strong negative stress for health.

Assembling the finished structure

The design of the furnace, which will be assembled independently according to its own or ready-made drawings, will depend on the material that is available. If a metal pipe with a large diameter is available, then you can assemble a structure, which will be discussed below.

Housing

It is good if the workpiece that will be used to assemble the structure will have a wall thickness of 8 mm. This will significantly extend its service life. Dimensions will be given in the description, but for each individual case they will depend on what height of the workpiece for the furnace structure is available. The first step is to thoroughly clean the workpiece from old paint, if any, and from rust.This is required for the convenience of work, and also so that the paint does not fade during operation.

After completing the preparatory process, you need to make two round blanks. One of them will be needed to organize the bottom of the furnace, and the second will be used to separate the tank capacity from the furnace. You can mark the circle with an impromptu compass and chalk. The easiest way to cut it is with a plasma welding machine or a grinder. You can do this with an autogenous gun, but in this case you will need to make an additional gap, since it burns several millimeters of material in width. After working with a grinder, additional processing of the structure will be needed to round off the edges, since it will be difficult to achieve an ideal result.

When the blanks can be used, one of them closes the end. It is necessary to boil it carefully and with a sufficiently powerful apparatus that can warm the metal well. The seam of the furnace structure must not have any flaws. After the bottom of the furnace is welded, you can start cutting a hole for the ash pan and firebox door. The first can be 25 × 12 cm, the second can be increased to 30 × 20 cm to make it easier to load firewood. It is necessary to cut the holes on the side where the hinges will be located. At the same time, it is not worth cutting to the end. The hinges are immediately tried on and welded into place. Only then can the finishing cut be made. This is the easiest way to install the hinges, since it will be much more difficult to position the door later.

The distance from the top point of the ash pan door to the bottom point of the firebox door should be 15 cm. The next step is to install the grate bars in the stove. They are mounted closer to the top point of the ash pan door. It is better not to weld them to the stove body, but to make them removable. To do this, you need to purchase cast iron blanks and make supports for them. This design will make it easier to clean the oven. In order not to clean the ash pan of the furnace with a spatula, a metal box can be made for it, which would be easily removed. After these two modules of the stove are ready, you can start making the tank and the stove for the stove.

Kamenka

The heater for a round metal stove can be organized in two ways. One of them is internal and the other is external. If you choose an internal heater for the stove, then there are also two manufacturing options for it. If a water tank is part of the structure, which will be located on top, then the heater for the heater will need a blank made of a metal pipe with a diameter of at least 30 cm. Its length should be equal to the width of the stove. One of the ends of such a stove is closed with a metal blank. A hole for the heater is cut into the stove assembly, and it is inserted inside and welded along the edge.

If there is no water tank on top of the stove, then this space can be separated for the heater. In this case, a partition is welded from the inside at a distance of 40 cm from the top. Stones will be stacked on it. Another option for the location of the stove in such a stove would be to place it outside. To do this, metal strips are welded around the perimeter, which should be at a distance of 15 cm from the body.It should look like a basket, which is in the photo. It is in it that the stones are placed.

Water tank

If the upper part of the stove structure will not be used as a heater, then it is easy to take it under the water tank. To do this, with the indentation that was indicated above, a wall is welded, which will serve as the bottom for the tank. Particular attention should be paid to the seam for this lintel in the furnace, if this is not done, then it will flow into the furnace and interfere with combustion. In this lintel for the stove, a hole is made for the chimney, which goes down inside.A pipe with a diameter of 115 or 125 mm can be used as a chimney to make it easier to dock with other components. The place where the pipe passes through the lintel of the furnace must also be welded well.

Half of the upper part is closed with a non-removable plug, and a cover is made for the second, through which hot water can be taken with a ladle. A small ½ ”male nipple is welded to the side wall. Using a drill, a hole is drilled through the fitting in the side wall. A tap is screwed onto it. It must be made at the bottom of the tank so that it is easy to drain water from it. Another tap can be fixed from above and a pipe can be brought to it through which water will be poured. A video on assembling such a furnace design can be viewed below.

Furnace installation

Before installing the oven, you need to prepare a place for it. It is advisable to make a concrete base by filling a small reinforced concrete foundation. Waterproofing and an asbestos sheet under the oven are laid on it. Legs are mounted on the stove, which will raise it above the floor by 15 cm. Around the stove, at the will of the walls, it is advisable to lay out a brick box, which will exclude their overheating and fire. If desired, the oven is covered with heat-resistant enamel, which does not have harmful emissions when heated.

What temperature should be in the steam room

After the firewood of the last bookmark has burned out, and the surface has become grayish, with the stirring of the coals, the tongues of flame are red, without blue flashes (carbon dioxide has not yet come out all, if blue tongues appear), it means that you can close the half-door and the firebox, open the valves.

By this time, the stones should already be well heated and the water should boil (the temperature in the steam room should rise to + 50- + 60 ° C).

The next step is to air the bathhouse. Everything that can be opened is opened, the entire steam compartment and stones are rinsed with boiling water. After airing, everything is closed, leaving only the window in the double room. This allows you to evenly warm up the bath for an hour and a half. Then close the window after this time. The steam room is ready and you can take a steam bath for your pleasure.

Summary

As you can see, it is quite possible to build a metal stove for a bath yourself. To do this, you must have the required tools, the main of which is a welding machine. When working on assembling the stove, you must follow the safety rules, wearing protective goggles, a respirator, gloves and clothing made of natural fibers.

The technology of manufacturing a sauna stove makes special demands on the equipment of all its departments, including the chimney. Its device is slightly different from the chimney system of a home stove. It must ensure long-term heat conservation and the safety of the steam room visitors. Before organizing a chimney in a bath, it is worth learning a few important nuances.

The design of sauna stoves includes 2 types of chimneys:

• Indigenous. They are organized next to the stove, using a special pipe for connection, through which the smoke goes into the main channel. One chimney can be used for 2-3 stoves. The main thing is that its inner diameter has the appropriate parameters, and the pipes from each heating device are located at different heights;
• Packed tube systems are mounted directly on the chimney and led out through the roof. This chimney option is the most common for sauna stoves.

The classification of chimneys at the place of installation includes 2 types:

• Outdoor. Most of them are located outdoors and fixed on the wall with a bracket. Not too recommended for a bath, as they cool down quickly, losing precious heat.
• Internal. These are vertical structures with good traction, located inside the building.

According to the material used, chimneys are:

• Brick.A traditional look, characterized by the laboriousness of masonry and high requirements for compliance with all parameters. They have a lot of advantages: durability, fire safety, strength, good thermal insulation and heat accumulation. The disadvantages include the roughness and angularity of the inner surface, on which soot deposits accumulate;
• A metal chimney is installed faster and costs less. It has a perfectly smooth surface, but weaker heat-retaining characteristics;
• Combined version, including 2 parts: the lower one is made of bricks, the upper one is made of a modern sandwich pipe. Allows you to organize neat, small passages that are easier to cover with heat-resistant material.

Reasons for the appearance

Asbestos pipes have a rough inner surface, so smoke comes out more slowly

Steam is contained in combustion products of all types of fuel. On contact with a cold surface, it becomes saturated and turns into water.

The reasons for the occurrence of condensation in the branch ducts are as follows:

• Excessive height of the sandwich pipe, when the head practically does not heat up.
• Lack of thermal insulation in the chimney of a gas boiler.
• Using raw firewood in a solid fuel boiler.
• Low exhaust gas temperature. This is typical for modern double-circuit boilers.
• Incorrectly planned canal shape, when there are many knees and horizontal sections along its length. The thrust decreases, the temperature drops.
• Roughness of the walls. They slow down the speed of the exhaust gases, which leads to cooling of the pipe and the formation of droplets.
• Lack of access to the required amount of fresh air to the blower - a defect in the furnace or an incorrectly planned ventilation system.

If a problem of condensation formation is detected, it must be dealt with by all available methods, without putting it on the back burner.

Chimney materials

Before purchasing materials, it is necessary to determine the structural features of the chimney.

Brick system

The structure is made of heat-resistant bricks using a special dry mix or kiln clay. In addition, you may need material to create a fungus above the pipe.

Metal construction

Before purchasing material for making a metal chimney in a bath, it is necessary to draw up its exact diagram with a detailed location of all corners and turns of the pipe.

You will also need 2 iron sheets with holes corresponding to the diameter of the pipe. They are fixed on the ceiling of the bathhouse and on the floor of the attic. You will also need heat-resistant material, which will be fixed around the pipe at its exit to the wooden attic.

To create waterproofing around the chimney on the roof, it is necessary to prepare a sealant or a special rubber seal.

The choice of pipes: what to look for

When buying iron chimneys, you need to decide on their cross section. Basically, it depends on the power of the stove, but for most sauna options this parameter is 15-20 cm.Do not take too large a diameter, as it will retain heat poorly. And too small - will not create the necessary draft for the extraction of smoke. Whatever it was, the cross-section of the pipe should not be less than the diameter of the outlet pipe of the heating structure.

There are a number of other requirements for the elements of the chimney in the bath:

• The minimum pipe height is 5 m. Neglect of this requirement threatens to deteriorate traction. The exact value is calculated depending on the location of the pipe on the roof. In any case, it should rise at least half a meter above the ridge. The ideal height from the ridge is considered to be 1.5 m, but this is not necessary;
• The minimum thickness of the metal used to create the pipe is 1 mm;
• If it is planned that the chimney system will be equipped with a hot water tank, then it must be reflected in a previously drawn up diagram. It is better if the tank is made of stainless steel.

Measuring the oven temperature. Video

The temperature of the oven in the bath. Findings:

• in a steam room that is only heating up, the wall temperature is always lower than the air temperature;
• do not worry that you covered the floor with acrylic varnish - it is almost always cold and does not heat up above 40 degrees;
• the arrow of the thermometer reacts very slowly to temperature jumps, because it integrally shows the temperature with the radiation of the thermometer body and walls;
• the heater mesh in the lower part is most of all thermally loaded, if you do not allow combustion in the pipe barrel itself, then it does not heat up more than 200 degrees!;
• the convector casing heats up more slowly than all other parts of the oven due to the strong flow of cold air from the floor to the top of the oven;
• in the summer period, when it takes 50 minutes to warm up the steam room to 85 degrees - it is IMPOSSIBLE to get a hot stone, use a steam generator or
• in steam rooms with pouring floors - the floors are colder than in dry steam rooms - they must be dried thoroughly;
• the outer screen of the sandwich pipe is heated to a greater extent from the air temperature, and not through the heat insulator inside!
• metal parts of the stove and mesh-stove are higher than other parts - the metal heats up faster

Of course, oven temperature in the bath

depends on hundreds of factors, which are very different in all baths, not to mention the weather, cravings, etc.

Consider all the nuances

In the construction of baths, it is wood that is most often used.

... This is not surprising: it is a warm, environmentally friendly, healthy, but ... also combustible material: under certain conditions, wood can ignite spontaneously at temperatures from 100 ° C.

Reed roof,

as in the project Bath under a hood, it requires even more attention.

● According to European standards and safety requirements for the placement of chimneys, the height from the ridge of the reed roof to the chimney outlet of solid fuel equipment must be at least 80 cm! Regardless of the distance to the chimney from the ridge.

● A spark arrester must be installed on the chimney, and the connection of the stove to the chimney must be made with a cleaning pocket.

● Under no circumstances is the flush-mounted version of the chimney permitted. The design of the spark arrester is designed in such a way that the mesh does not clog quickly, and the diameter of the stainless rods and the size of the mesh are designed so that sparks cannot pass by. Installing a conventional mesh as a spark arrester can lead to a rapid overgrowth of soot, which is more dangerous for combustible roofs to ignite.

Chimneys for wood-burning stoves
combined with a reed roof
used in countries with milder climates (in the diagram of the UK standards for chimneys for reed roofs), but at the same time, the chimney without a spark trap must rise above the roof at least 180 cm.

Operate the oven correctly

Sauna heaters direct flue gases into the chimney

with a maximum operating temperature of 600 ° C. And with improper operation or construction of the stove, the temperature in the chimney can reach 900 ° C. The process of heating a sauna stove often takes place continuously and for a long time. So most often a fire occurs in a sauna attic - and precisely because of the heating of combustible structures by the chimney!

An important prerequisite for safety

is the observance of the rules for the operation of furnaces. Prefabricated oven manufacturers detail these rules in their instructions.

● Avoid excessive draft (hum) in the chimney.

● Regulation is carried out by supplying air to the combustion chamber.

● The quantity and quality of firewood must exactly correspond to the instructions of the manufacturer of the stove.

In case of violation of the firebox rules

wood gas can burn out in the chimney, overheating the structures of the roof and ceilings. Particular attention should be paid to this in winter.The relative humidity of the air is low (the likelihood of spontaneous combustion of combustible materials increases), and the temperature difference most of all contributes to the formation of super-thrust.

Choose your pipe wisely

The bathhouse often lacks constant heating.

... And, for example, for brick pipes, "salvo" fires are simply destructive. High-temperature flue gases heat up the system, thermal stresses arise, and cracks appear in the brick chimney due to the temperature difference between the external and internal environment.

The use of steel sandwiches for sauna stoves requires special attention.

The maximum operating temperature that stainless steel can withstand without changing the metal structure is 600 ° C. Continuous heating of a furnace with such pipes for more than 4 hours can lead to the transfer of heat to the enclosing structures.

In addition, not all double-circuit steel chimneys

suitable for operating temperatures of 600 ° C - many are designed to operate up to a maximum of 400 ° C. Above 400 ° C, stainless steel loses its properties faster and burns out, and it is the insulation layer that burns out, and the thicker it is, the faster.

However, the single-loop steel pipe

radiates heat too intensely and can heat combustible structures to spontaneous combustion at a distance of up to 400 mm. Therefore, the use of a non-insulated chimney in places close to combustible structures is unacceptable.

Double-circuit pipes should be used especially carefully.

for sauna stoves in the presence of a room above the steam room with the presence of people. The possibility of touching should be excluded. In such cases, European regulations require the placement of steel sandwiches in fire-resistant ventilated mines.

Fundamentally different material

used in chimney systems for sauna stoves is ceramics. Ceramics for temperatures above 300 ° C must be insulated without fail for uniform heating. At the same time, it is not afraid of prolonged overheating and is even tested for resistance to temperatures up to 1000 ° C.

The safest solution

able to withstand temperature loads for a long time, protecting the bath from fire, is a ceramic system with internal ventilation.

In ceilings, the distance from combustible structures

should be at least 10 cm to the surface of ceramic systems and 20 cm - to double-circuit steel systems. Regular indoor ventilation will remove excess heat and moisture from the insulation and outer shell.

Homemade sauna stoves cost on average 3-5 times cheaper than factory products. The savings will be even greater if the welding work is done independently. When making with your own hands, you will need to decide on the following:

1. What metal to make a stove for a bath.
2. What is the optimal metal thickness.
3. What type of electrodes should be used to ensure maximum weld strength.

The answer to all these questions determines the speed of heating the steam room, the duration and intensity of operation of a self-made furnace.

Content of water vapor in flue gases

To determine the dew point of flue gases (i.e. the temperature at which condensate falls out of the DG), it is necessary to know the density of water vapor in the DG, which depends on the composition of the fuel, its moisture content, the excess air ratio and temperature. The vapor density is equal to the mass of water vapor contained in 1 m3 of flue gases at a given temperature.

Formulas for the volume of a DW were derived in this work, Section 6.1, formulas A1.3 - A1.8. After transformations, we obtain an expression for the vapor density in flue gases depending on the moisture content of the wood, the excess air ratio and temperature. The humidity of the source air makes a small correction and is not taken into account in this expression.

The formula has a simple physical meaning. If we multiply the numerator of the large fraction by 1 / (1 + w), then we get the mass of water in DG, in kg per kg of wood. And if we multiply the denominator by 1 / (1 + w), then we get the specific volume of the DW in nm3 / kg.The multiplier with temperatures is used to convert normal cubic meters into real ones at a temperature T. After substituting the numbers, we get the expression:

The dew point of flue gases can now be determined graphically. Let us superimpose the graph of the steam density in the DG on the graph of the density of saturated water vapor. The intersection of the graphs will correspond to the dew point of the DG with the corresponding humidity and excess air. In fig. Figures 3 and 4 show the result.

Fig. 3.

The dew point of flue gases with excess air unit and different moisture content of the wood.

Fig. 3 it follows that in the most unfavorable case, when burning wood with a moisture content of 100% (half of the mass of the samples is water) without excess air, condensation of water vapor will begin at about 70 * C.

Under conditions typical for batch furnaces (wood moisture 25% and an excess of air about two), condensation will begin when the flue gases are cooled to 46 * C. (see fig. 4)

Fig. four.

Flue gas dew point at 25% wood moisture and various excess air.

Fig. 4 it is also clearly seen that excess air significantly lowers the temperature of condensation. Adding excess air into the chimney is one of the ways to eliminate condensation in pipes.

Correction for variability of fuel composition

All of the above considerations are valid if the composition of the fuel remains unchanged over time, for example, gas is burned in the trough or pellets are fed continuously. In the case of burning firewood in a batch oven, the composition of the flue gases changes over time. First, volatiles burn out and moisture evaporates, and then the carbon residue burns out. Obviously, in the initial period, the content of water vapor in the DG will be significantly higher than the calculated one, and at the stage of combustion of the coal residue it will be lower. Let's try to roughly estimate the dew point temperature in the initial period. Let the volatiles burn out from the bookmark in the first third of the heating process, also all the moisture contained in the bookmark evaporates during this time. Then the concentration of water vapor in the first third of the process will be three times higher than the average. At 25% wood moisture content and a 2-fold excess of air, the vapor density will be 0.075 * 3 = 0.225 kg / m3. (see FIGURE, blue graph). The condensation temperature will be 70-75 * С. This is an approximate estimate, since it is not known how, in reality, the composition of the DG changes as the bookmark burns out. In addition, unburned volatiles condense from the flue gases together with water, which, apparently, will slightly increase the dew point of the DG.

What brand of steel is better for a sauna stove

The heating temperature of flue gases inside the furnace reaches 450-550 ° C. When heated at such an intensity, deformation of the metal is observed.
Direct exposure to fire causes the steel to burn out. Of course, you can simply use metal with a thickness of 10 mm or more, but then you have to heat the steam room for a long time, spend a lot of fuel to warm up. Due to the use of thick-walled steel sheets, a durable furnace will become economically disadvantageous.

The task facing the master is to make the structure strong enough to prevent deformation, burnout and at the same time having good thermal conductivity. At the factory, metal with a high degree of heat resistance is used for the manufacture of sauna stoves.

Most manufacturers use the grade of chromium corrosion-resistant stainless steel AISI 430. In budget models, iron for bath stoves is changed to structural steel GOST 1050-88. Each metal has its own pros and cons.

Alloy steel differs from structural steel in the following characteristics:

Chromium-containing heat-resistant steel is expensive and not all components experience the same thermal and corrosive stress.For this reason, the construction of a sauna stove is made of several metals:

• Firebox - AISI 430 or analogue 08X17T is used for the combustion chamber. For self-production, steel 10 GOST 1050-88 is used.
• Screen - convection channels do not experience the same load as the firebox, therefore, for their production, 08PS or 08U GOST 19904-90 are taken.
• The body of the sauna stove is made of structural steel sheet.
• Combustion chamber door - practice shows that this part of the device experiences maximum thermal stress. For this reason, using even highly alloyed stainless steel is not enough. After several fireboxes, deformation of the doors is observed. The best solution is to hang a cast-iron door.

As a rule, in the independent manufacture of a sauna stove, metal is used, which is easier to machine and weld.

Combustion temperature and heat transfer

The combustion temperature of wood determines the heat transfer rates of the fuel - the higher it is, the more heat energy is released during the combustion of firewood. In this case, the specific heating value of the fuel depends on the characteristics of the wood.

The heat transfer values ​​in the table are indicated for firewood burned under ideal conditions.

:

• minimum moisture content in the fuel;
• combustion takes place in a closed volume;
• oxygen supply is metered - the amount that is necessary for full combustion is supplied.

It makes sense to be guided by the tabular values ​​of the calorific value only for comparing different types of firewood with each other - in real conditions, the heat transfer of the fuel will be noticeably lower.

What is combustion

Combustion is an isothermal phenomenon - that is, a reaction with the release of heat.

The process of burning firewood can be divided into several stages.

:

1. Warming up. The piece of wood must be heated with an external fire source to the ignition temperature. When heated to 120-150 degrees, the wood begins to char, and coal is formed, capable of spontaneous combustion. When heated to 250-350 degrees, the process of thermal decomposition into gaseous components (pyrolysis) starts. The upper, charred layer smolders (burns without the formation of a flame), while white or brown smoke is released - a mixture of water vapor with pyrolysis products.

2. Combustion of pyrolysis gases. Further heating leads to increased thermal decomposition, and the concentrated pyrolysis gases flare up. After the outbreak, the fire gradually begins to cover the entire heating zone. This produces a stable light yellow flame.

3. Ignition. Further heating will ignite the wood. The ignition temperature in natural conditions ranges from 450 to 620 degrees. Wood ignites under the influence of an external source of thermal energy, which provides heating necessary for a sharp acceleration of the thermochemical reaction.

The flammability of wood fuel depends on a number of factors

:

• volumetric weight, shape and section of a wood element;
• the degree of moisture in the wood;
• traction force;
• the location of the object to be ignited relative to the air flow (vertical or horizontal);
• density of wood (porous materials ignite more easily and faster than dense ones, for example, it is easier to light alder wood than oak).

Note! Wet wood ignites and burns worse due to the fact that a significant part of the heat energy is spent on evaporating excess moisture. Round firewood burns worse than elements with edges and edges. The more massive the wood, the more difficult it is to light it up. Unplanned wood will ignite faster than smooth wood.

For ignition, good, but not excessive traction is required - a sufficient supply of oxygen and a minimum dissipation of thermal energy of combustion are required - it is needed to warm up adjacent sections of wood.

four.Combustion. Under conditions close to optimal, the initial outbreak of pyrolysis gases does not fade, from ignition the process turns into stable combustion with a gradual coverage of the entire volume of fuel. Combustion is divided into two phases - smoldering and flaming combustion.

Optimum metal thickness for the oven in the bath

When determining the thickness of the metal, two main characteristics are taken into account that affect the operating parameters of the sauna stove:

• Burning out of steel - if a thin-walled sheet of ordinary metal is used for the firebox, after literally six months of the firebox, the furnace will have to be repaired. Ordinary steel 4 mm thick will provide quick heating of the steam room, but will not last long. For this reason, manufacturers make the combustion chamber from AISI 430, heat-resistant chrome stainless steel with a thickness of 4-6 mm.
• Thermal conductivity - the heating temperature of the furnace directly depends on the thickness of the furnace walls. It seems that it was easier to make a combustion chamber of metal 10 mm or more, and so prevent burnout, but this approach is inappropriate for several reasons. The thicker the metal, the more heat energy and time is required to warm it up and maintain the required temperature. Furnace equipment becomes economically unprofitable. The optimum metal thickness for a sauna stove should be 6-8 mm.

The minimum thickness of steel in the combustion chamber is 4 mm, permissible only if AISI 430 and 08X17T are used. In other cases, a metal thickness of at least 6 mm is required. Most craftsmen recommend using structural steel with a thickness of 8 mm when making a furnace on their own.

What electrodes should be used to cook a sauna stove

To weld a furnace, you will need electrodes, selected depending on the steel used in the production. The stainless steel is cooked by argon arc welding. Electrodes of the TsL 11 and D4 brands are suitable.
After welding, descaling and pickling are mandatory. In this way, corrosion at the weld seam can be avoided.

Electrodes for welding sauna stoves made of structural steel NIAT-5, EA-112/15, EA-981/15 and EA-981/15. The thickness is selected, depending on the density of the metal and the temperature of its heating.

The service life of the stove largely depends on the competent conduct of welding, including the choice of consumables and the subsequent processing of the seam. It is better to cook the firebox for a professional. Welding work on stainless steel requires a category 5-6 welder qualification.

It is not difficult to make a stove for a bath with your own hands, if you have special skills, a competent choice of components and consumables.