Boilers are distinguished by the following features:

By appointment:

Energeticallye- producing steam for steam turbines; they are distinguished by high productivity, increased steam parameters.

Industrial- producing steam both for steam turbines and for the technological needs of the enterprise.

Heating- producing steam for heating industrial, residential and public buildings. These include and hot water boilers. Hot water boiler - a device designed to produce hot water with a pressure above atmospheric pressure.

Waste heat boilers- designed to produce steam or hot water through the use of heat from secondary energy resources (SER) in the processing of chemical waste, household waste, etc.

Energy technology- are designed to produce steam by means of HOR and are an integral part of technological process(e.g. soda recovery units).

According to the design of the combustion device(Fig. 7):

Rice. 7. General classification of combustion devices

Distinguish fireboxes layered - for burning lumpy fuel and chamber - for combustion of gas and liquid fuels, as well as solid fuels in a pulverized (or finely crushed) state.

Layer furnaces are subdivided into furnaces with a dense and fluidized bed, and chamber furnaces are divided into direct-flow flare and cyclone (vortex) furnaces.

Chamber furnaces for pulverized fuel are divided into furnaces with solid and liquid ash removal. In addition, by design they can be single-chamber and multi-chamber, and by aerodynamic mode - under vacuum and supercharged.

Basically, a vacuum scheme is used, when a pressure less than atmospheric pressure is created in the gas ducts of the boiler by a smoke exhauster, that is, a vacuum. But in some cases, when burning gas and fuel oil or solid fuels with liquid ash removal, a pressurized circuit can be used.

Diagram of a pressurized boiler. In these boilers, a high-pressure blower unit provides overpressure in the combustion chamber 4 - 5 kPa, which allows you to overcome the aerodynamic resistance of the gas path (Fig. 8). Therefore, in this scheme there is no smoke exhauster. The gas tightness of the gas path is ensured by the installation of membrane screens in the combustion chamber and on the walls of the boiler flues.

Advantages of this scheme:

Relatively low capital costs for brickwork;

Lower compared to a boiler operating under vacuum, electricity consumption for own needs;

More high efficiency by reducing losses with outgoing gases due to the absence of air suction into the gas path of the boiler.

Flaw- the complexity of the design and manufacturing technology of membrane heating surfaces.

By type of coolant generated by the boiler: steam and hot water.

For the movement of gases and water (steam):

Gas-tube (fire-tube and with smoke tubes);

Water pipe;

Combined.

Scheme of a fire-tube boiler. The boilers are designed for closed systems heating, ventilation and hot water supply and are produced for operation at an allowable working pressure of 6 bar and allowable temperature water up to 115°C. The boilers are designed to operate on gaseous and liquid fuels, including fuel oil and crude oil, and provide an efficiency of 92% when working on gas and 87% on fuel oil.

Steel hot water boilers have a horizontal reversible combustion chamber with a concentric arrangement of fire tubes (Fig. 9). To optimize the heat load, combustion chamber pressure and flue gas temperature, the fire tubes are equipped with stainless steel turbulators.

Rice. 8. Scheme of the boiler under "pressure":

1 - air intake shaft; 2 - high-pressure fan; 3 - air heater of the 1st stage; 4 - water economizer of the 1st stage; 5 - air heater of the 2nd stage; 6 - hot air ducts; 7 - burner device; 8 - gas-tight screens made of membrane pipes; 9 - flue

Rice. 9. Scheme combustion chamber fire tube boilers:

1 - front cover;

2 - boiler furnace;

3 - fire tubes;

4 - tube boards;

5- fireplace part of the boiler;

6 - mantel hatch;

7 - burner device

By way of water circulation all the variety of designs of steam boilers for the entire range of operating pressures can be reduced to three types:

- with natural circulation- rice. 10a;

- with multiple forced circulation - rice. 10b;

- once-through - rice. 10th century

Rice. 10.Water circulation methods

In boilers with natural circulation, the movement of the working fluid along the evaporative circuit is carried out due to the difference in the densities of the columns of the working medium: water in the downcomer feed system and the steam-water mixture in the upward evaporative part of the circulation circuit (Fig. 10a). The driving pressure of circulation in the circuit can be expressed by the formula

, Pa,

where h is the height of the contour, g is the free fall acceleration, , is the density of water and steam-water mixture.

At critical pressure, the working medium is single-phase and its density depends only on temperature, and since the latter are close to each other in the downcomer and lifting systems, then the driving pressure of the circulation will be very small. Therefore, in practice natural circulation it is used for boilers only up to high pressures, usually not higher than 14 MPa.

The movement of the working fluid along the evaporative circuit is characterized by the circulation ratio K, which is the ratio of the hourly mass flow rate of the working fluid through the evaporative system of the boiler to its hourly steam output. For modern ultra-high pressure boilers K = 5-10, for low and medium pressure boilers K is from 10 to 25.

A feature of boilers with natural circulation is the method of arranging heating surfaces, which consists in the following:

downpipes should not be heated to maintain sufficient high level ;

· lifting pipes should be of such a design as to exclude the formation of steam locks during the movement of the steam-water mixture through them;

velocities of water and mixture in all pipes must be moderate to obtain low hydraulic resistance, which is achieved by choosing pipes of heating surfaces sufficient large diameter(60 - 83 mm).

In boilers with multiple forced circulation, the movement of the working fluid along the evaporation circuit is carried out due to the operation of the circulation pump, which is included in the downward flow of the working fluid (Fig. 10b). The circulation ratio is kept low (K=4-8), because circulation pump guarantees its preservation during all load fluctuations. Boilers with multiple forced circulation allow you to save metal for heating surfaces, as increased speeds water and working mixture, thus partially improving the cooling of the pipe wall. At the same time, the dimensions of the unit are somewhat reduced, since the diameter of the tubes can be chosen smaller than for boilers with natural circulation. These boilers can be used up to critical pressures of 22.5 MPa, the presence of a drum makes it possible to dry steam well and blow through contaminated boiler water.

In once-through boilers (Fig. 10c), the circulation ratio is equal to one and the movement of the working fluid from the inlet to the economizer to the outlet of the superheated steam unit is forced, carried out by the feed pump. There is no drum (a rather expensive element), which gives a certain advantage to direct-flow units at ultrahigh pressure; however, this circumstance causes an increase in the cost of station water treatment at supercritical pressure, since the requirements for the purity of the feed water, which in this case should contain no more impurities than the steam produced by the boiler, increase. Once-through boilers are universal in terms of operating pressure, and at supercritical pressure they are generally the only steam generators and are widely used in modern electric power industry.

There is a type of water circulation in once-through steam generators - combined circulation, carried out by a special pump or an additional parallel circulation circuit of natural circulation in the evaporative part of a once-through boiler, which makes it possible to improve the cooling of screen pipes at low boiler loads by increasing the mass circulating through them by 20-30%. working environment.

Scheme of a boiler with multiple forced circulation for subcritical pressure is shown in fig. eleven.

Rice. eleven. Structural scheme boiler with multiple forced circulation:

1 - economizer; 2 - drum;

3 - lower feed pipe; 4 - circulation pump; 5 - distribution of water through the circulation circuits;

6 - evaporative radiation heating surfaces;

7 - festoon; 8 - superheater;

9 - air heater

The circulation pump 4 operates with a pressure drop of 0.3 MPa and allows the use of small diameter pipes, which saves metal. The small diameter of the pipes and the low circulation ratio (4 - 8) cause a relative decrease in the water volume of the unit, therefore, a decrease in the dimensions of the drum, a decrease in drilling in it, and hence a general decrease in the cost of the boiler.

The small volume and independence of the useful circulation pressure from the load allow you to quickly melt and stop the unit, i.e. operate in control mode. The scope of boilers with multiple forced circulation is limited by relatively low pressures, at which it is possible to obtain the greatest economic effect due to the reduction in the cost of developed convective evaporative heating surfaces. Boilers with multiple forced circulation have found distribution in heat recovery and combined-cycle plants.

Direct flow boilers. Once-through boilers do not have a fixed boundary between the economizer and the evaporative part, between the evaporative heating surface and the superheater. When the temperature of the feed water, the operating pressure in the unit, the air regime of the furnace, the moisture content of the fuel and other factors change, the ratios between the heating surfaces of the economizer, the evaporative part and the superheater change. So, when the pressure in the boiler decreases, the heat of the liquid decreases, the heat of evaporation increases and the heat of overheating decreases, therefore the zone occupied by the economizer (heating zone) decreases, the evaporation zone increases and the overheating zone decreases.

In once-through units, all impurities coming with feed water cannot be removed with blowing like drum boilers and are deposited on the walls of heating surfaces or are carried away with steam into the turbine. Therefore, once-through boilers place high demands on the quality of the feed water. To reduce the risk of pipe burnout due to the deposition of salts in them, the zone in which the last drops of moisture evaporate and steam overheating begins is taken out of the furnace at subcritical pressures into a convective gas duct (the so-called remote transition zone).

In the transition zone, there is an energetic precipitation and deposition of impurities, and since the temperature of the pipe metal wall in the transition zone is lower than in the furnace, the risk of pipe burnout is significantly reduced and the thickness of the deposits can be allowed to be greater. Correspondingly, the interflushing working campaign of the boiler is lengthened.

For supercritical pressure units, the transition zone, i.e. a zone of increased salt precipitation is also present, but it is greatly extended. So, if for high pressures its enthalpy is measured as 200-250 kJ/kg, then for supercritical pressures it increases to 800 kJ/kg, and then the implementation of a remote transition zone becomes impractical, especially since the salt content in the feed water is so low here, which is almost equal to their solubility in vapor. Therefore, if a boiler designed for supercritical pressure has a remote transition zone, then this is done only for reasons of normal flue gas cooling.

Due to the small storage volume of water in once-through boilers important role plays the synchronism of the supply of water, fuel and air. If this compliance is violated, wet or excessively superheated steam can be supplied to the turbine, and therefore, for once-through units, automation of the control of all processes is simply mandatory. Once-through boilers designed by Professor L.K. Ramzin. A feature of the boiler is the layout of radiant heating surfaces in the form of a horizontally ascending winding of tubes along the walls of the furnace with a minimum of collectors (Fig. 12).

Rice. 12. Structural scheme of Ramzin's once-through boiler:

1 - economizer; 2 - bypass unheated pipes; 3 - bottom distribution manifold water; 4 - screen pipes; 5 - upper collection manifold of the mixture; 6 - remote transition zone; 7 - wall part of the superheater; 8 - convective part of the superheater; 9 - air heater; 10 - burner

As practice later showed, such shielding has both positive and negative sides. Positive is the uniform heating of individual tubes included in the tape, since the tubes pass along the height of the furnace all temperature zones under the same conditions. Negative - the impossibility of performing radiation surfaces with factory large blocks, as well as an increased tendency to thermal hydraulic reamers(uneven distribution of temperature and pressure in pipes along the width of the gas duct) at ultrahigh and supercritical pressure due to a large increment of enthalpy in a long coil.

For all systems of direct-flow units, some General requirements. So, in a convective economizer feed water before entering the furnace screens, it is not heated to boiling by about 30 ° C, which eliminates the formation of a steam-water mixture and its uneven distribution along the parallel tubes of the screens. Further, in the zone of active fuel combustion, in the screens, a sufficiently high mass velocity ρω ≥ 1500 kg/(m 2 s) is provided at a nominal steam output D n, which guarantees reliable cooling of the screen tubes. About 70 - 80% of the water turns into steam in the furnace screens, and the remaining moisture evaporates in the transition zone and all steam is superheated by 10-15 ° C to avoid salt deposits in the upper radiation part of the superheater.

In addition, steam boilers are classified according to steam pressure and steam output.

Steam pressure:

Low - up to 1 MPa;

Medium from 1 to 10 MPa;

High - 14 MPa;

Ultra-high - 18-20 MPa;

Supercritical - 22.5 MPa and above.

By performance:

Small - up to 50 t/h;

Medium - 50-240 t/h;

Large (energy) - over 400 t / h.

Boiler marking

The following indices are established for marking boilers:

- Type of fuel : TO- coal; B- brown coal; WITH- slates; M- fuel oil; G- gas (when fuel oil and gas are burned in a chamber furnace, the index of the type of furnace is not indicated); O- waste, garbage; D- other types of fuel;

- firebox type: T- chamber furnace with solid slag removal; F- chamber furnace with liquid slag removal; R- stratified furnace (the index of the type of fuel burned in the stratified furnace is not indicated in the designation); V- vortex furnace; C- cyclone furnace; F- fluidized bed furnace; an index is introduced into the designation of pressurized boilers H; for seismically resistant design - index WITH.

- circulation method: E- natural; Etc- multiple forced;

Pp- once-through boilers.

The numbers indicate:

- for steam boilers- steam capacity (t/h), superheated steam pressure (bar), superheated steam temperature (°С);

- for hot water- heat output (MW).

For instance: Pp1600-255-570 J. Once-through boiler with a steam capacity of 1600 t/h, superheated steam pressure - 255 bar, steam temperature - 570 °C, furnace with liquid ash removal.

Boiler layout

The layout of the boiler means the mutual arrangement of gas ducts and heating surfaces (Fig. 13).

Rice. 13. Boiler layout diagrams:

a --- U-shaped layout; b - two-way layout; c - layout with two convective shafts (T-shaped); g - layout with U-shaped convective shafts; e - layout with an inverter furnace; e - tower layout

The most common U-shaped layout (Fig. 13a - one-way, 13b - two-way). Its advantages are the supply of fuel to the lower part of the furnace and the removal of combustion products from the lower part of the convection shaft. The disadvantages of this layout are the uneven filling of the combustion chamber with gases and the uneven washing of the heating surfaces located in the upper part of the unit with combustion products, as well as the uneven concentration of ash over the cross section of the convective shaft.

T-shaped the layout with two convective shafts located on both sides of the furnace with the lifting movement of gases in the furnace (Fig. 13c) makes it possible to reduce the depth of the convective shaft and the height of the horizontal flue, but the presence of two convective shafts complicates the removal of gases.

three way the layout of the unit with two convective shafts (Fig. 13d) is sometimes used for the upper location of smoke exhausters.

Four way the layout (T-shaped two-way) with two vertical transition gas ducts filled with discharged heating surfaces is used when the unit is operating on ash fuel with low-melting ash.

Tower the layout (Fig. 13e) is used for peak steam generators operating on gas and fuel oil in order to use the self-draught of gas ducts. In this case, difficulties arise associated with the fastening of convective heating surfaces.

U - shaped the layout with an inverter furnace with a downward flow of combustion products in it and their lifting movement in a convective shaft (Fig. 13e) ensures good filling of the furnace with a torch, a low location of superheaters, and minimal resistance of the air path due to the short length of the air ducts. The disadvantage of this arrangement is the degraded aerodynamics of the transition gas duct, due to the location of burners, smoke exhausters and fans on high altitude. Such an arrangement may be appropriate when the boiler is operating on gas and fuel oil.

On the modern market there are a wide variety of models of heating boilers. Fundamental difference between different models is the energy carrier that ensures their operation. It can be gas, electricity, solid fuels, liquid fuels, or combinations thereof.

However, the device various models very similar, only some specific nuances differ.

The heating boiler is key element heating system. It can also be used to provide hot water in the house. Depending on the functionality, it can be single-circuit or two-circuit. The first are intended exclusively for heating, the second - for heating and heating water.

Single and double circuit heaters

The device of a single-circuit device includes only a circuit with a coolant, which provides heating of the radiators in the heating system. Water or antifreeze can act as a coolant. To provide hot water, you must connect to single-circuit device special boiler.

If you have a double-circuit boiler installed, then you will not need to install and connect an additional boiler. One of them will provide heating of the heat carrier of the heating system, and the second - the water that will be supplied to the hot water supply pipeline.

In most cases, as an energy carrier for heating boiler gas is used. The popularity of this type of fuel is associated with its relative availability and low cost. Some models of gas-fired equipment are equipped with closed camera combustion. In this case, the room air will not be used for gas combustion. Such a device allows you to install equipment in any room of the house; you do not need to equip a special separate boiler room for this.

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The main and auxiliary elements of the boiler design

Fuel distribution can be carried out through a special manifold, and for safety reasons the device is equipped with a flame control system. This helps prevent fire or gas explosions. The design of the heating boiler includes a burner with special rods for heat removal. If it's not about gas equipment, then in place of the burner there is a firebox or a heating element, depending on the energy carrier used. The body is equipped with an efficient heat-insulating layer, which allows you to use heat to the maximum benefit.

Must include the following elements:

• a system for adjusting the operation, including a pressure indicator and distribution valves, which make it possible to evenly distribute the supply of heated coolant both to the radiators closest to the boiler and to the most distant ones;
• firebox, burner or piezo lighter;
• a spiral along which the coolant moves;
• ignition transformer;
• main switch.

In addition to control devices and heating elements, the device of heating equipment includes expansion tank and circulation pump. The first is designed to receive a coolant, which will increase in volume after heating. The second ensures the movement of the coolant through the system.

Interesting design of the combined devices. For example, if the boiler can operate on gas and diesel, then to change the working fuel, it is enough to replace the head. Combined boilers are appropriate if you plan to convert in the future heating system and change the main type of fuel used. In this case, you do not have to replace the equipment.

Modern heaters are equipped with a dashboard that allows you to easily monitor the correct operation of the device. Even boilers for solid fuels can have such panels, including indicators of temperature, pressure, and more.

Thus, the device of modern heating boilers is constantly being improved and becomes more and more functional. Thanks to this, the operation of any model of the boiler is greatly simplified.

A steam boiler is a device that is used in everyday life and industry. It is designed to turn water into steam. The resulting steam is subsequently used to heat housing or rotate turbomachines. What are steam engines and where are they most in demand?

A steam boiler is a machine for producing steam. In this case, the device can produce 2 types of steam: saturated and superheated. Saturated steam has a temperature of 100ºC and a pressure of 100 kPa. Superheated steam is characterized by high temperature (up to 500ºC) and high pressure (more than 26 MPa).

Note: Saturated steam is used in heating private houses, superheated - in industry and energy. It transfers heat better, so the use of superheated steam increases the efficiency of the plant.

Where are steam boilers used?

1. In a heating system, steam is the energy carrier.
2. In the energy sector, industrial steam engines (steam generators) are used to generate electricity.
3. In industry, superheated steam can be used to convert into mechanical motion and move vehicles.

Steam boilers: scope

household steam devices used as a source of heat for home heating. They heat a container of water and drive the resulting steam into the heating pipes. Often such a system is equipped with a stationary coal furnace or boiler. Usually, Appliances for heating with steam, only saturated, unsuperheated steam is created.

For industrial applications the steam is superheated. It is continued to be heated after evaporation in order to further raise the temperature. Such installations require high-quality execution in order to prevent the explosion of the steam tank.

The superheated steam from the boiler can be used to generate electricity or mechanical motion. How does this happen? After evaporation, the steam enters steam turbine. Here the flow of steam rotates the shaft. This rotation is further processed into electricity. This is how electrical energy is obtained in the turbines of power plants - when the shaft of turbomachines rotates, an electric current is generated.

Beyond Education electric current, the rotation of the shaft can be transmitted directly to the engine and to the wheels. As a result, the steam transport comes into motion. Famous example steam engine- locomotive. In it, when coal was burned, water was heated, formed saturated steam, which rotated the motor shaft and wheels.

The principle of operation of the steam boiler

The source of heat for heating water in a steam boiler can be any type of energy: solar, geothermal, electric, combustion heat solid fuel or gas. The resulting steam is a coolant, it transfers the heat of combustion of the fuel to the place of its application.

V various designs steam boilers use a general scheme for heating water and turning it into steam:

• The water is cleaned and fed into the tank with the help of an electric pump. As a rule, the reservoir is located at the top of the boiler.
• From the tank, water flows down the pipes to the collector.
• From the collector, the water rises again upward through the heating zone (fuel combustion).
• Inside the water pipe, steam is formed, which, under the influence of the pressure difference between the liquid and gas, rises up.
• At the top, the steam passes through a separator. Here it is separated from the water, the remains of which are returned to the tank. The steam then enters the steam line.
• If this is not a simple steam boiler, but a steam generator, then its pipes again pass through the combustion and heating zone.

Steam boiler device

A steam boiler is a container inside which heated water evaporates and forms steam. As a rule, this is a pipe of various sizes.

In addition to the pipe with water, the boilers have a combustion chamber (fuel burns in it). The design of the furnace is determined by the type of fuel for which the boiler is designed. If it is hard coal, firewood, then there is a grate at the bottom of the combustion chamber. It has coal and firewood. From below, air passes through the grate into the combustion chamber. For effective traction (air movement and fuel combustion), fireboxes are arranged at the top.

If the energy carrier is liquid or gaseous (fuel oil, gas), then a burner is introduced into the combustion chamber. For the movement of air, they also make an entrance and exit (grate and chimney).

Hot gas from the combustion of fuel rises to a container of water. It heats the water and exits through the chimney. Water heated to boiling point begins to evaporate. The steam rises and enters the pipes. This is how the natural circulation of steam occurs in the system.

Classification of steam boilers

steam boilers classified according to several criteria. According to the type of fuel on which they work:

• gas;
• coal;
• fuel oil;
• electrical.

By purpose:

• household;
• industrial;
• energy;
• recycling.

By design features:

• gas-pipe;
• water pipe.

Let's look at the difference between the design of gas-tube and water-tube machines.

Gas and water tube boilers: differences

The steam generating vessel is often a pipe or several pipes. The water in the pipes is heated by hot gases formed during the combustion of fuel. Devices in which gases rise to pipes with water are called gas-tube boilers. The scheme of the gas-tube unit is shown in the figure.

Scheme of a gas-tube boiler: 1 - fuel and water supply, 2 - combustion chamber, 3 and 4 - fire tubes with hot gas that goes further through the chimney (positions 13 and 14 - chimney), 5 - grate between pipes, 6 - water inlet , the output is marked with the number 11 - its outlet, in addition, there is a device for measuring the amount of water at the outlet (marked with the number 12), 7 - the steam outlet, the zone of its formation is marked with the number 10, 8 - a steam separator, 9 - the outer surface of the tank, in which water circulates.

There are other designs in which the gas moves through a pipe inside a container of water. In such devices, water tanks are called drums, and the devices themselves are called water-tube steam boilers. Depending on the location of the water drums, water tube boilers are classified into horizontal, vertical, radial, as well as combinations of different pipe directions. A diagram of the movement of water through a water-tube boiler is shown in the figure.

Scheme of a water-tube boiler: 1 - fuel supply, 2 - furnace, 3 - pipes for water movement; the direction of its movement is indicated by the numbers 5,6 and 7, the place of entry of water is 13, the place of exit of water is 11 and the place of drain is 12, 4 is the zone where water begins to turn into steam, 19 is the zone where there is both steam and water , 18 - steam zone, 8 - partitions that direct the movement of water, 9 - chimney and 10 - chimney, 14 - steam outlet through the separator 15, 16 - outer surface of the water tank (drum).

Gas and water tube boilers: comparison

To compare gas and water tube boilers, here are some facts:

1. The size of the pipes for water and steam: for gas-tube boilers, the pipes are larger, for water-tube boilers, they are smaller.
2. The power of a gas-tube boiler is limited by a pressure of 1 MPa and a heat-generating capacity of up to 360 kW. This is due to the large size of the pipes. They can generate a significant amount of steam and high pressure. An increase in pressure and the amount of heat generated requires a significant thickening of the walls. The price of such a boiler with thick walls will be unreasonably high, not economically profitable.
3. The power of a water-tube boiler is higher than that of a gas-tube boiler. Small diameter pipes are used here. Therefore, the steam pressure and temperature can be higher than in gas-tube units.

Note: Water tube boilers are safer, more powerful, produce high temperature and allow significant overloads. This gives them an advantage over gas-tube units.

Additional elements of the unit

The design of a steam boiler may include not only a combustion chamber and pipes (drums) for the circulation of water and steam. Additionally, devices are used that increase the efficiency of the system (raise the temperature of the steam, its pressure, quantity):

1. Superheater - raises the temperature of the steam above +100ºC. This, in turn, increases the economy and efficiency of the machine. The temperature of superheated steam can reach 500 ºC (this is how steam boilers work in nuclear power plants). The steam is additionally heated in the pipes into which it enters after evaporation. At the same time, it can have its own combustion chamber or be built into a common steam boiler. Structurally, convection and radiation superheaters are distinguished. Radiation structures heat steam 2-3 times more than convection ones.
2. Vapor separator - removes moisture from the steam and makes it dry. This increases the efficiency of the device, its efficiency.
3. A steam accumulator is a device that takes steam from the system when there is a lot of it, and adds it to the system when there is not enough of it.
4. Water preparation device - reduces the amount of oxygen dissolved in water (which prevents corrosion), removes minerals dissolved in water (with chemical reagents). These measures prevent clogging of pipes with scale, which impairs heat transfer and creates conditions for burning pipes.

In addition, there are condensate drain valves, air heaters, and, of course, a monitoring and control system. It includes a switch and a burner switch, automatic regulators consumption of water, fuel.

Steam generator: powerful steam engine

A steam generator is a steam boiler that is equipped with several additional devices. Its design includes one or more intermediate superheaters, which increase the power of its operation by dozens of times. Where are powerful steam engines used?

Steam generators are mainly used in nuclear power plants. Here, with the help of steam, the energy of the decay of an atom is converted into electricity. Let us describe two methods for heating water and generating steam in a reactor:

1. Water washes the reactor vessel from the outside, while it heats up itself and cools the reactor. Thus, the formation of steam occurs in a separate circuit (water is heated against the walls of the reactor and transfers heat to the evaporation circuit). In this design, a steam generator is used - it acts as a heat exchanger.
2. Pipes for heating water run inside the reactor. When pipes are fed into the reactor, it becomes a combustion chamber, and the steam is transferred directly to the electric generator. This design is called a boiling water reactor. There is no need for a steam generator.

Industrial steam units - powerful machines that provide people with electricity. Household units - also work in the service of man. Steam boilers allow you to heat the house and perform various jobs, and also give the lion's share electrical energy for metallurgical plants. Steam boilers are the backbone of industry.

21.01.2017

Creating a heating boiler on your own is good method save money. There are many modifications of boilers that you can make yourself. However, the simplest of them, perhaps, is the Kholmov boiler. This device, for at least, at first, hardly seems effective enough, and therefore many prefer other designs. In part, these people are right, because the efficiency of Kholmov's heating device is not so high, but its circuit is extremely simple, which greatly simplifies the manufacturing process.

The device and design features of the Kholmov boiler

Kholmov's boiler means a shaft-type design. This means that the combustion chamber, as well as the section with the heat exchanger, are arranged vertically in this case. Such boilers operate on solid fuel, which can also be firewood. Power industrial models, which can be purchased in specialized outlets, is 10, 12 and 25 kilowatts. If the fuel compartment is fully loaded, it can provide continuous heating of a medium-sized room within 12-16 hours.

All Kholmov boilers can be of two types:

• volatile;
• non-volatile.

Now let's take a closer look internal organization the described heater. So, it includes such constructive elements:

• frame;
• thermostat;
• fuel mine;
• inlet / outlet required for inlet, outlet and drain, installation of a safety group or safety valves;
• a chamber in which the heat exchanger is located;
• branch pipe for connecting a chimney pipe;
• grate;
• thermal expansion compensators;
• doors;
• ash pan.

As you can see, there are not very many elements. As for weight, for example, a boiler with a capacity of 12 kilowatts weighs about 255 kilograms. The standard dimensions are as follows (HxWxD): 124x48.5x66 centimeters. For this reason, you will not have any difficulties in bringing such a boiler, say, into a doorway. Models with a power of 10 kilowatts differ little from those described above (both in terms of parameters and in terms of appearance), but the main difference lies in the internal design.

The upper doors of the device are double, and inside there is a thermal insulation material (in fact, because of this, they do not warm up above 80 degrees). The edges of the doors are glued with asbestos sealant, and a special heat-resistant paint is used for painting. For closing back cover there are 4 quick-release screws, everything else is closed with special locks. In addition, the bottom door of the ash compartment is only 40 percent closed with thermal insulation material, but its temperature, as a rule, does not exceed 90 degrees, since the element is cooled by permanent air currents.

Important information! The bottom of the chamber is not the most bottom heating device. The latter is a special plate with a pair of long legs and a thermal insulator located inside.

Thanks to all this, the Kholmov boiler received not only a fairly high efficiency, but also a sufficient degree of fire safety. As a result, the device may well be installed even on a floor made of wood.

If we consider specifically the non-volatile models of the Kholmov heater, then they are additionally equipped with a fan or a smoke exhauster, as well as a special controller designed to control the process. However, non-volatile devices are still the most popular. The working process in them is regulated by means of a special thermostat, which is located on the front wall. This thermostat is connected via a chain to a small blower door.

The door itself is designed to supply air into the boiler, which is required to maintain the combustion process. It is located on the large door of the ash compartment. The whole is never closed, since there must be a special gap required for the minimum passage of air masses.

At the top of the back is a branch pipe, and a chimney is connected to it, in turn. This element, by the way, is intended to create natural traction. As a result, air is supplied to the device through the blower door. Behind a pair of cast iron grates (which, by the way, are removable) is an auxiliary welded grate, which is also called a hump, because it is located above a couple of others.

Under grate there is an ash box (ash is collected in it). If the door is open, this drawer can be easily pulled out for later cleaning. The working fluid is drained through a special half-inch pipe, which is located at the bottom of the boiler. A similar element is available for the fuse pipe or safety group. Products for receipt and "return" have larger size, the return pipe is located at the bottom, and the outlet is at the top.

Important information! In order to avoid expansion of the heating device to critical dimensions and divergence of seams, expansion compensators are present in the device.

The latter are available around the perimeter of the boiler. In addition, they are in the body - they are made in the form of partitions / rods. The distance between the dividing walls is 24 centimeters. As for the heat exchanger, such compensators are not provided for by the design, since the dimensions given element allow it to retain its own form.

Video - How the Kholmov boiler with a capacity of 25 kilowatts works

Features of the operation of mine boilers

Air enters under the grate and directly into the boiler through the blower door, so the fuel is burned. When this happens, they form flue gases- they are removed through the gas gap. Kholmov's boiler has such a design that the volume of air that is supplied through the blower door is initially not enough for proper combustion. As a result, a certain chemical burn is observed during the operation of the device.

In our case, chemical underburning indicates that during the oxidation an unclean carbon dioxide, and he, but already in combination with carbon monoxide. The air that passes under the auxiliary grate is drawn into the holes on it. The number of these holes is such that the amount of secondary air is already too much. The heat stress in this place is quite high and can reach 700-800 degrees, as a result of which the remnants of carbon monoxide are oxidized.

Important information! If you look into the peephole, which is located in the rear upper door, you will see that the fire breaks out of the holes on the auxiliary grate (yellow or bluish, as when gas is burned).

After oxidation, the gas moves to the radiation compartment of the combustion chamber. There it is mixed, rises and is divided into a couple of streams thanks to the exchanger. Further, through the outlet pipe, the gas enters directly into the chimney. convective thermal energy is taken by the exchanger and the walls located next to it. The working fluid after passing through the inlet, respectively, hits the wall, after which it spreads and moves through the entire device between the heat exchanger and the chambers. The already heated coolant is supplied to the heating system through the outlet pipe in the upper part of the device.

Boiler drawing

Do-it-yourself instructions for making a Kholmov boiler

Below is step-by-step instruction to create a Kholmov boiler on their own. The power of the device to be considered is 8-10 kilowatts.

In accordance with the drawings that are shown in the video below, the dimensions of the product will look something like this:

1. 0.8 meters in height;
2. 0.47 meters wide;
3. 0.576 meters deep (if you add a door with a neck, you get 0.63 meters).

Video - Mining solid fuel boiler

Stage one. We prepare everything you need

For the manufacture of the Kholmov boiler, be sure to acquire:

• sheet steel with a thickness of 0.3-0.4 centimeters;
• an iron rod with a diameter of 1 centimeter and a length of 47 centimeters;
• asbestos cord (recommended dimensions - 1.5x1.5 centimeters);
• pipes - the diameter should be 1.5, 2, 4 and 11.5 centimeters.

As for the amount of consumables, it should be selected based on the selected drawing. Of course, do not forget about a small margin.

Stage two. Building the interior

This part is, in fact, a structure consisting of four walls and having a water partition. The manufacturing process should begin just from the construction of this water partition. The element should look like this:

1. 48.5 centimeters high;
2. 40.3 centimeters wide;
3. 6 centimeters deep.

As for the partition, it is, in fact, a pair of vertical walls, to which the bottom and top are welded. In the center it is necessary to weld a compensator, which is a U-shaped metal element. This compensator is welded at the very beginning to one of the walls. If we talk about end partitions, then in this case they are not required.

Then, in order to make Kholmov's cauldron, you need to adhere to the following algorithm of actions.

Step 1. cut out sheet metal inner side walls of the heater. If you look at the videos and drawings, you can conclude that the height of these walls ranges from 77 centimeters, and the width is 54.6 centimeters. However, these are not ordinary rectangles, because a rectangle should be located in front of the bottom corner vertical type with dimensions of 20.8x8 centimeters, and on the same side, but on top, horizontal with dimensions of 38.7x3 centimeters. In addition, you must cut holes on these sides for a water partition. They should be located 2 centimeters from the top side and 10.2 centimeters from the back.

Step 3 Weld all the elements described above into one structure. Use spot welding for this. So the details will be combined into one whole, but if necessary, you will have the opportunity to adjust their location.

Step 4 Next, you need to weld a couple metal arches. The first of them should be U-shaped, and the second - solid. Fix the first at the bottom of the welded structure, and the second at the top. It is important that the angle between these elements and the walls is 90 degrees. As for the frame, you can cut it out of the same sheet metal, although you can alternatively weld it using metal strips 3 centimeters wide each.

Step 5 After that, thoroughly boil each of the seams.

Step 6 Make another frame in the shape of the letter "P". At the same time, its dimensions should be such that it can easily fit inside the unit. Install this frame above the water partition (the distance between them should be 9 centimeters).

Step 7 To the upper parts of the rectangles protruding in the front, weld horizontally an iron strip 40.3 centimeters long and 8 centimeters wide.

Step 8 At the top of the back side, cut a round hole with a diameter of 11.5 centimeters.

Stage three. Building the outer part

Now proceed to the manufacture of doors and outer walls of the water jacket. The sequence of actions in this case should be as follows.

Step 1. Cut out the outer walls from sheet metal in the form of ordinary rectangles. The dimensions of the front side should be 46.3x56.2 centimeters, the side - 57.6x77 centimeters, and the rear - 46.3x77 centimeters.

Step 2 In the front wall, cut a couple round holes for compensation (as an option, these holes can be diamond-shaped) with a diameter of 1 centimeter. Make sure that the holes are located on a single vertical line. And in the upper right corner, make another hole, this time with a diameter of 1.5 centimeters. This hole will be required for the thermometer.

Step 3 Make holes in the back wall as well. This should be a pair of compensation and 3 more auxiliary ones (for a chimney, a working fluid supply with a diameter of 4 centimeters and a drain valve with a diameter of 1.5 centimeters).

Step 4 We continue to build the Kholmov boiler. Now in the side walls you need to make 4 holes for compensation. In this case, the first pair on the walls should be flush with the jacket compensator, and an iron bar will subsequently have to be inserted and welded here. Drill a couple of holes in the left wall - 4 centimeters in diameter (for the output of the working fluid) and 2 centimeters (for the thermostat).

Step 5 Make expansion joints in the form of the letter "P" in the amount of ten copies. Dimensions should be 3x4x4 centimeters (height, width and length, respectively).

Step 6 Weld these expansion joints to the corresponding holes in the outer walls.

Step 7 Weld all outer walls to the inside.

Step 8 Weld the chimney and pipes.

Step 9 Weld four bolts at the top of the structure. They should be located around the perimeter of the heat exchange chamber.

Step 10 Check the structure for tightness. Take plugs for this and put them on each of the nozzles, then pour liquid into the device. Raise the pressure indicator to approximately 2.2 bar. Standard operating pressure the described device will be 1.5 bar. If you find leaks, be sure to seal them.

Step 11 At the end, weld the bottom.

Stage four. We make a threshold, doors and a grate

As for the nut, this is a cover rectangular shape with a number of holes and sides. The dimensions of this element should be 5.5x16x40 centimeters, and the algorithm for its manufacture is given below.

Step 1. Take the sheet metal first.

Step 3 Fold up the sides.

Step 4 Weld the joints thoroughly.

Step 5 Make 1.2 cm holes along one of the 40 cm sides in the amount of 14 pieces.

Video - Self-manufacturing of a mine boiler

Note! Turn the nut upside down, place it in the body so that it is located under the water partition on the bottom. The gap in this case should be approximately 3.5 centimeters.

The dimensions of the grate, in accordance with the drawings on the Internet, should be 20x40 centimeters, although the holes in the bottom in this case should already be longitudinal. Make the main part of the door in the same way as the threshold, then cut an 8x19 cm hole in the upper part. It is important that the opening is closed with a flap cover with curtains that are welded over the resulting opening.

Glue the door around the perimeter with an asbestos cord, using a heat-resistant sealant. Weld the ears under the hinges on one side, and an iron strip with a slot in the center on the other. A special handle will fit just into this slot.

In the end, it remains only to make the roofs of the combustion / heat exchange chambers using the same technology as the main part of the doors. That's all, as you can see, Kholmov's boiler has enough simple design, therefore, it is quite possible to cope with the manufacture on their own. Good luck with your work!