Boiler for heating by own hands

The main part, the heart of any heating system is boiler .The variety of their kinds and designs can amaze all imagination. And, we must give credit, many modern boilers are both economical and efficient devices. They have fine adjustments, are equipped with automation and can work without human intervention. Some models can even send a SMS to the owner and "report" on the thermal situation in the house, and the owner can order the desired temperature by his mobile phone or via the Internet connection for his arrival. But there are cases when it is profitable to make boiler for heating by one's own hands. For example, for heating a cottage or a greenhouse.

The Internet is literally overloaded with various information on the independent manufacture of heating boilers. The completely unexpected components are used, which did not reflect beforehand to be part of the boiler;some technical solutions can compete with inventions design offices;The efficiency of some boilers is not inferior to the best boilers of famous manufacturers. But unfortunately, the Internet and a lot of "junk" information, which can not help anything, and in some cases is capable of doing harm. The authors of some reviews boast that nothing is easier than producing

boiler independently, although in reality this is not an easy task. The purpose of this article is to understand which heating boilers are worthy of making them independently and what are the features of the technological process of their manufacture.

Types of heating boilers and the possibility of their own manufactured

task of heating boiler - heated using any fuel coolant and transfer it to the heating system, which already distributes the heat consumers. It is by the type of fuel used that boilers are divided into several large classes. Consider these classes and immediately determine the feasibility of their independent manufacture.

• Gas heating boilers - currently - this is the most economical type of fuel. Modern gas boilers have high efficiency, are easily controlled, operate without human intervention. The self-manufacturing of gas boilers is possible , but it is absolutely not recommended. Firstly, because gas is a dangerous fuel and any unauthorized interference can lead to unfortunate consequences, and, secondly, no gas supply organization will give permission for the operation of a self-made gas boiler. And he will do it right.

• Liquid-fuel boilers are used where there is no gasification and other types of fuel. These boilers have a very high high efficiency , they are easy to automate, but their application is associated with certain difficulties in storing large amounts of fuel: diesel fuel or fuel oil. Self-manufacturing of liquid fuel boilers is prohibited, no fire inspector will put his signature when putting the house into operation, if it is equipped with non-certified equipment. And, probably, very few people will want to live on a powder keg.

• Electric heating boilers have a clear advantage over all others in the simplicity of their design, small overall dimensions, easy operation. These boilers are relatively easy to make by yourself. But all these advantages are offset by high prices for electricity. Unfortunately, electricity heating is economically unprofitable. It is understandable, because a significant part of the electricity is received by by burning hydrocarbon fuel. Another is one significant limitation that not always power supply organizations will give permission to allocate high power.

• Solid fuel heating boilers , despite the assurances of skeptics about their imminent retirement, continue to work successfully to this day. Moreover, they are experiencing a real second birth. As fuel they use firewood, coal, peat briquettes, oil shale and other types of solid fuel. Very interesting boilers that use a special kind of fuel - pellets , made from wood waste. These boilers are amenable to automation, have high efficiency , but production and logistics pellet is still at an embryonic level. For self-manufacturing, solid-fuel boilers are the most suitable, so we will consider them. But special attention is deserved by one of the representatives of solid fuel boilers - pyrolysis .

Solid pyrolysis heating boilers

The classic solid fuel is , made of metal: steel or cast iron. It burns solid fuel, while generating thermal energy transferred to the heat carrier by means of heat exchangers. At the same time, is supplied with to the combustion chamber to maintain combustion of the fuel. If the covers the air supply, then the combustion process will slow down, and if the is opened if the is opened, it will go faster this way to regulate the power of the classic solid fuel boilers.

There are boilers adapted only for the of the specific fuel type: wood, coal, pellets , - but there are models that work on any fuel. Solid-fuel boilers can be either with natural draft or with forced draft. The efficiency of a well-designed and executed classical solid fuel boiler can reach 71-79%.The advantages of such boilers are:

• Availability and low-cost on fuel.
• Ability to use several types of fuel.
• Ability to incinerate waste from wood processing and agricultural processing.
• Complete autonomy of work, independence from electricity.

However, classic solid fuel boilers have a number of disadvantages that can not be ignored:

• On one fuel load, the boilers work not for more than 4-6 hours.
• The need to store large amounts of fuel requires additional space.
• The download is mostly done in manual mode.
• Classic solid fuel boilers require constant cleaning from combustion products.
• Process with burning has inertia, it is difficult to control.

In the category of solid fuel boilers it is worthwhile to single out the so-called pyrolysis boilers, which work behind the account of separate combustion of fuel and the resulting decay products - pyrolysis gases. Consider the operation of such a boiler by example.

Fuel( this is most often firewood) through the upper loading door is loaded into the gasification chamber. The throttle choke is fully opened and the firewood is ignited. This includes the fan that the is supplying to the air chamber. Naturally, firewood starts to burn as in a conventional solid fuel boiler.

After the wood has inflamed, close the upper door and block the choke choke. The air continues to flow to the fuel, but in a limited amount, so I start the firewood t t at a temperature of 200 to 800 ° C.Under these conditions, the pyrolysis reaction takes place: decomposition of wood into solid part in the form of coal and light - pyrolysis gases, which are fed through the nozzle into the combustion chamber. The is also fed to the via the secondary air supply duct with a heated mixture. In conditions of high temperatures pyrolysis gases are ignited and oxidized by the supplied air. The combustion temperature is about 1100 ° C.

Hot gases from pass through multiple smoke channels, which are located in the heat medium of the heating system - water. There is a transfer of heat energy. The high temperature in the combustion chamber supports the pyrolysis process in the gasification chamber. If it is necessary to report the firewood to the gasification chamber, then fully open the chimney choke, wait a few minutes for the chamber to ventilate from pyrolysis gases and the usual combustion process began. After that, open the door, report the firewood, close the door and the damper( throttle) of the chimney. The process of pyrolysis and afterburning of gases in the lower chamber is resumed.

Caution: In boilers with primary and secondary air injection, the load door can only be opened after opening the chimney flap and pause. Otherwise, when the door is opened, the pyrolysis gases accumulated in the gasification chamber can ignite. This disadvantage is deprived of pyrolysis boilers not with air injection, but with a smoke exhauster, where vacuum is created in the chambers.

Pyrolysis heating boilers have the following advantages:

• In pyrolysis boilers complete combustion of fuel takes place, which allows cleaning the ash pit and high-temperature flues much more rarely.

• Combustion of pyrolysis gases can be easily controlled, which makes the boiler control automated.
• The combustion process in the gasification chamber is controlled by the supply of primary air. Burning is slow, and this allows one to work on firewood from 5-7 hours to several days( for boilers of upper combustion).
• In pyrolysis boilers can burn large, not chopped firewood.
• Wood waste, plywood trim, chipboard , fiberboard , MDF can be used as fuel.
• Pyrolysis boilers are 3 times less emitted into the atmosphere of harmful substances.

Disadvantages of pyrolysis boilers:

• For the operation of a fan or a smoke exhauster, electricity is required, so care must be taken to equip the boiler with a powerful uninterruptible power supply.
• At a fuel humidity of more than 20%, the efficiency of the boiler falls sharply.
• In the case of small loads, there may be differences in the operation of the boiler, which affects the deposition of tar in the flue channels. For a constant boiler load, a heat accumulator may be required - for storing heat energy.

heat accumulator

• In order to avoid condensation in the boiler flues, the temperature of the return must be maintained at least 60 ° C.Condensation leads to accelerated low-temperature corrosion of the boiler.
• The impossibility of organizing an automatic fuel supply.
• Pyrolysis boilers are very material-intensive, so they are 1.5-2 times higher than the classic solid fuel.

As in pyrolysis boilers high-temperature combustion takes place( 1100-1200 ° C), the lower part of the gasification chamber and the entire combustion chamber, including the door, must be specially protected with a liner-a special heat-resistant liner. Given the high temperatures, the lining is made either with chamotte bricks or special heat-resistant mullite-corundum concrete. What is the function of the lining:

• Protection of the metal surfaces of the boiler chambers against high temperatures, which prevents the metal from burning out.
• For the successful flow of the gas evolution and combustion of pyrolysis gases, the defined temperature regime is required. When the flame contacts the cooled metal, an abundant release of condensate can take place, and the lining allows the reaction temperature to be kept constant.

Boiler for self heating

Before starting the manufacture of pyrolysis boiler, it is necessary to accurately determine its dimensions, which largely depend on the required power. Insufficient boiler capacity will not allow to compensate for all the heat losses, and excess capacity will require the discharge of the heat accumulator .

Usually, when calculates , it is assumed that for heating 10 m2 of housing space, 1 kilowatt of boiler power is required. Suppose you want to heat 250 m2 of the area of ​​a country house. It turns out that the boiler should have a power of at least 25 kW.The following figures show the drawing of the boiler and the conformity table of dimensions - the boiler power.

Boiler Size Chart This data will guide the calculating the of a future design. It is best to use ready-made drawings of the already made and successfully working one season of boilers. These boilers have already worked out typical errors and their authors can readily share the drawings with the detailed specification of that boiler that will meet the for all needs. Naturally - it's not free, but the amount of $ 50-70 is simply ridiculous compared to what the - -homemade grief can wait for on the path to the desired boiler.

It is highly recommended that you make 3D visualization of all parts of the boiler in AutoCAD or any other suitable program in order to better understand the internal device and to work out the correct strategy for making the boiler.

The required tool and materials for the manufacture of boiler

For the pyrolysis boiler, the following tool is needed:

• Welding inverter.
• Electric drill with set drilled for metal of different diameters.
• Angle grinder( bulgaria) for a circle with a diameter of 230 mm.
• Angle grinding machine for a circle of 125 mm.
• For cutting large diameter holes, a gas cutter or( ideally) the is required. If they do not exist, then with the defined skill, this can be done by the Bulgarian.

• Standard set of metalwork tools: hammer, chisel, files, clamps and more.

Boiler material:

• For the gasification chamber and combustion chamber , it is better to use sheet steel 5 mm, and for the outer skin 4 mm. It will take approximately 7-10 m2 of the sheet, depending on the model. In extreme cases, you can do for the entire boiler with a sheet of 4 mm.
• Pipe diameter 57 mm wall thickness 3.5 mm for heat exchangers - 8 - 10 m .
• Pipe diameter 159 mm with a wall thickness of 4.5 mm for the hog( horizontal outlet of the chimney from the boiler) - 0, 5 m .
• Fireclay refractory brick SHA -8 - 15-25 pcs.

• Pipe diameter 32 mm with wall thickness 4.5 mm - 2 m .
• Profile pipe 60 * 30 * 2 mm - 2 m .
• Profile pipe 80 * 40 * 2 mm - 2 m .
• Strip steel 30 * 4 mm - 2 m .
• Electrodes - 5-6 packs.
• Circles cutting-off 230 mm - 10 pcs.
• Circles cutting-off 125 mm - 10 pcs.
• Grinding wheels 125 mm - 5 pcs.
• Centrifugal fan blower .

• Temperature sensor.

The list given by is very approximate and is not an exact instruction for execution. Everything should be purchased on the basis of individual calculations. N averny something have to buy, and something will remain in surplus.

Manufacture of the pyrolysis boiler

It is best to make an optimal plan for cutting the steel sheet onto preforms in advance, according to the existing drawings and to cut it into rectangular blanks immediately when purchasing metal warehouse at .This service, of course, is worth the money, but gives advantages in time and quality. Bulgaria is such an even cut, as in cutting, it is almost impossible to do. Standard dimensions of steel hot-rolled sheet thickness of 3-5 mm are 1.5 * 6 m .

. We note the basic stages of manufacturing pyrolysis of the boiler:

• After the cutting of the blanks, it is possible to begin to make the inside of the boiler, namely to weld the chambers: gasifying and burning. Mounting is better done from two halves.

• After the chamber frame has been welded, it is possible to weld the rear wall and air ducts in the gasification chamber. In the photo they are made of a channel, but this is completely unnecessary, a profile tube of 60 * 30 * 2 mm is sufficient, in which pre-drill holes with a diameter of 10 mm. Pay attention to the cutout in the back wall under the chimney channel.

• A secondary air supply pipe is connected to the combustion chamber, which is connected to the boiler façade using a 20 * 20 mm profile pipe.

• It's time to prepare the heat exchanger. To do this, the burned plate is burned by gas cutter holes for flue pipes with a diameter of 57 cm. In the absence of a torch, it is possible to burn a large current with an electrode, but this method is worse.

• Heat exchanger tubes are cut, they are mounted on the support plates, they are welded. After checking the dimensions, all joints are welded. The heat exchanger is ready.

• The has its own heat exchanger welded to the .At the same stage, the throttle valve of the chimney is manufactured and installed.

• The front wall of the boiler chambers is welded, previously holes are made in it for the primary and secondary air supply pipes.

• chambers At the throttle and flue outlet, the back cover and burs are welded.

• The inside of the boiler is assembled. Now it is necessary to thoroughly clean the welded seams with a grinding disc and check their quality.
• 4 mm sheet steel is used as the outer skin of the boiler. For the its fixings on the boiler body are welded on the corner pieces of the number 25.

• boiler. On the previously marked and cut sheet of skin, through holes with a diameter of 10-12 mm are made at the location of the corners.

• All holes are welded to ensure that the sheathing plate is securely attached to the base by the .

• In the same way, all sides of the boiler are clad except the top cover. All joints are thoroughly welded and cleaned.

• It is now time to check the tightness of all welds. To do this, all the inlet, outlet and outlet openings of the heating medium are muffled and the boiler is filled with water through the top cover. Check for leakage. If a leak is detected, this place is marked with chalk for further correction.

• For the inspection of the chimneys, a tunnel is made for the top cover, isolated from the water jacket of the boiler and only then the upper part of the boiler is welded.

• seal. Adjustment of the air dampers is done with threaded studs.

• All air openings are covered with a common casing, from which a common air duct is drawn from the profile pipe.

• Make and hang the doors for the boiler chambers. As the lining of the door, you can use either cast iron plates or fireclay bricks. The seal is made with a ceramic cord.

• The lining of the lower part of the gasification chamber up to the air ducts is made of fireclay bricks. For this, the brick is sawed with the help of a grinder with a stone cutting disk. Bring the brick to the desired size by hand on the grinding stone.

• The generated power of the pyrolysis depends on the geometric dimensions of the slit in the lower part of the gasification chamber. Therefore, in the manufacture of lining stones, in the table should be taken into account in order to ensure that the boiler's capacity is in accordance with the design.

• The flange is welded to the main pipe of the main duct, and then the centrifugal fan is attached.

• Fireclay lining made of fireclay is made of fireclay.

• To improve the heat transfer of the boiler it is recommended to place the so-called swirlers ( turbulators, ) into the flue gas ducts of the heat exchanger, which, first, slow the movement of hot gases and thereby improve heat transfer, and, secondly, They are used for cleaning the pipe from .

• . For , the swirlers are attached to the rocker arm, which is connected to a lever that is pulled outward. By rocking the lever, you can quickly clean the channels.

• . Before starting the boiler, you should check its tightness and to press with its pressure of 4 bar. For this, all openings in the boiler are muffled, except for the supply and return heating system. The boiler is filled with water completely and a pressure test device is connected to it.

• by the pressure test. The pressure is adjusted to 3 bar by the pressure-pressing machine. If the pressure immediately drops, then somewhere there is leak , which must be detected and eliminated. If the pressure does not change within half an hour, then we can assume that boiler is sealed and it can be integrated into the heating system.
• For providing for accident-free operation of the boiler, the boiler safety group is mounted on the heating pipe through the threaded fitting, which includes the emergency valve , the automatic air vent and the pressure gauge. If abnormal situations occur, the valve set to pressure 3 bar will relieve the excess pressure.

• Pyrolysis boiler is preferably equipped with an automatic control unit that will monitor the boiler operation mode with the help of temperature sensors and, if necessary, stop and start it. About how automatic control is implemented in boilers is shown in the video.

Video: Automation for pyrolysis boiler

Enter pyrolysis boiler

Before starting for the first time to , it must be connected to the chimney . and fill with water. The empty boiler is strictly prohibited to run - this will cause the to overheat. In addition, each boiler should have a thermometer that monitors the temperature of the coolant, which is screwed into a specially dedicated for this location. In all projects of boilers there must be holes for the thermometer, as well as thermo sensors.

• The fan through the switch is connected to the mains and its operation is checked. All air flaps are placed in the middle position.
• At the bottom of the gasification chamber , puts the paper so that it looks out from under the nozzle into the combustion chamber, and the is already stacked with .The first loading of firewood should not be large, just a few small logs. The gasification chamber door is closed tightly.
• The throttle flap of the flue gas chimney opens completely, the fan turns on and the paper is ignited.
• When the burning of firewood becomes sure, after a few minutes, the throttle flap of the chimney closes. Firewood should go into the slow burning mode( smoldering), which is accompanied by the release of pyrolysis gases. Through the bottom door of the combustion chamber, the ignition of the combustion torch of pyrolysis gases is monitored. If it does not catch fire, you should try to reduce the air supply to the gasification chamber and increase the to the combustion chamber.
• After the flame is ignited, the damper controls its intensity and color. The white-yellow flame color indicates the correct setting of the boiler.

• The combustion chamber door is closed and the time is displayed when the boiler will bring the water to a boil. The temperature is controlled by a thermometer. As only , the water reaches 100 ° C - the fan is turned off. The torch in the combustion chamber should go out. The water temperature after this should decrease.
• When the choke flap is opened, the flame in the combustion chamber must also go out.

Conclusion

• Pyrolysis long-burning boilers are complex devices, therefore their independent manufacture should be made only according to the drawings of those boilers that have already proven themselves in operation.
• Self-manufacturing requires strict adherence to technology with verification of each stage.
• Pyrolysis boilers are very material-intensive, even for their independent manufacture, a lot of expensive metal takes away. They will pay off only when they are in constant use for several seasons.

Video: Making a pyrolysis boiler for heating the house