A boiler plant (boiler room) is a structure in which the working fluid (heat carrier) (usually water) is heated for the heating or steam supply system, located in the same technical room. Boiler rooms are connected to consumers using heating mains and / or steam pipelines. The main device of the boiler room is a steam, fire tube and / or hot water boilers. Boiler houses are used for centralized heat and steam supply or for local heating of buildings.

A boiler plant is a complex of devices located in special rooms and serving to convert the chemical energy of the fuel into thermal energy of steam or hot water. Its main elements are a boiler, a combustion device (firebox), feed and draft devices. In general, a boiler plant is a combination of a boiler (s) and equipment, including the following devices: fuel supply and combustion; purification, chemical preparation and deaeration of water; heat exchangers for various purposes; initial (raw) water pumps, network or circulation - for circulation of water in the heat supply system, make-up - to replace water consumed by the consumer and leaks in networks, feed pumps for supplying water to steam boilers, recirculation (mixing); feed tanks, condensation tanks, hot water storage tanks; blowing fans and air duct; smoke exhausters, gas duct and chimney; ventilation devices; systems for automatic regulation and safety of fuel combustion; heat shield or control panel.

A boiler is a heat exchanger in which the heat from the hot combustion products of the fuel is transferred to the water. As a result, in steam boilers, water turns into steam, and in hot water boilers it is heated to the required temperature.

The combustion device is used to burn fuel and convert its chemical energy into heat of heated gases.

Feeding devices (pumps, injectors) are designed to supply water to the boiler.

The draft device consists of blowing fans, a system of gas ducts, smoke exhausters and a chimney, with the help of which the required amount of air is supplied to the furnace and the movement of combustion products through the boiler gas ducts, as well as their removal into the atmosphere. Combustion products, moving along the gas ducts and in contact with the heating surface, transfer heat to the water.

To ensure more economical operation, modern boiler plants have auxiliary elements: a water economizer and an air heater, which respectively serve to heat water and air; devices for fuel supply and ash removal, for cleaning flue gases and feed water; thermal control devices and automation equipment that ensure the normal and uninterrupted operation of all parts of the boiler room.

Depending on the use of their heat, boiler houses are divided into power, heating and production and heating.

Power boiler houses supply steam to steam power plants that generate electricity and are usually part of a power plant complex. Heating and industrial boilers are located at industrial enterprises and provide heat to the heating and ventilation systems, hot water supply of buildings and production processes. Heating boiler houses solve the same problems, but serve residential and public buildings. They are divided into free-standing, interlocked, i.e. adjacent to other buildings, and embedded in buildings. Recently, more and more freestanding enlarged boiler houses are being built with the expectation of servicing a group of buildings, a residential quarter, a microdistrict.

The device of boiler houses built into residential and public buildings is currently allowed only with appropriate justification and agreement with the sanitary supervision authorities.

Low-power boiler houses (individual and small group) usually consist of boilers, circulation and feed pumps and draft devices. Depending on this equipment, the dimensions of the boiler room are mainly determined.

2. Classification of boiler plants

Boiler plants, depending on the nature of the consumers, are divided into energy, production-heating and heating. According to the type of heat carrier obtained, they are divided into steam (for generating steam) and hot water (for generating hot water).

Power boiler plants generate steam for steam turbines in thermal power plants. Such boiler houses are usually equipped with boilers of large and medium power, which generate steam with increased parameters.

Industrial heating boiler plants (usually steam) generate steam not only for industrial needs, but also for heating, ventilation and hot water supply.

Heating boiler installations (mainly hot water, but they can also be steam) are designed to service heating systems of industrial and residential premises.

Depending on the scale of heat supply, heating boiler houses are local (individual), group and district.

Local boiler houses are usually equipped with hot water boilers with water heating to a temperature of no more than 115 ° C or steam boilers with an operating pressure of up to 70 kPa. Such boiler rooms are designed to supply heat to one or more buildings.

Group boiler plants provide heat to a group of buildings, residential areas or small neighborhoods. They are equipped with both steam and hot water boilers with a higher heating capacity than boilers for local boiler houses. These boiler rooms are usually located in specially constructed separate buildings.

District heating boilers are used to supply heat to large residential areas: they are equipped with relatively powerful hot water or steam boilers.

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It is customary to conventionally show individual elements of the basic diagram of a boiler plant in the form of rectangles, circles, etc. and connect them with each other by lines (solid, dotted), denoting a pipeline, steam pipelines, etc. There are significant differences in the schematic diagrams of steam and hot water boiler plants. A steam boiler plant (Fig. 4, a) of two steam boilers 1, equipped with individual water 4 and air 5 economizers, includes a group ash collector 11, to which the flue gases go through a collecting hog 12. For suction of flue gases in the area between the ash collector 11 and chimney 9 installed smoke exhausters 7 with electric motors 8. For the operation of the boiler room without smoke exhausters installed dampers (dampers) 10.

Steam from the boilers through separate steam pipelines 19 enters the common steam pipe 18 and through it to the consumer 17. Having given off heat, the steam condenses and through the condensate pipe 16 returns to the boiler room to the collecting condensation tank 14. Through pipe 15, additional water from the water pipe or chemical water treatment is supplied to the condensation tank (to compensate for the volume not returned from consumers).

In the case when part of the condensate is lost at the consumer, from the condensation tank a mixture of condensate and make-up water is supplied by pumps 13 through the feed pipeline 2, first to the economizer 4, and then to the boiler 1. The air required for combustion is sucked in by centrifugal blowing fans 6 partially from the room the boiler room, partly outside and through the air ducts 3, it is supplied first to the air heaters 5, and then to the boiler furnaces.

The hot water boiler plant (Fig. 4, b) consists of two hot water boilers 1, one group water economizer 5 serving both boilers. The flue gases at the outlet of the economizer through the common collecting hog 3 are fed directly into the chimney 4. The water heated in the boilers enters the common pipeline 8, from where it is supplied to the consumer 7. Having given off heat, the cooled water is first sent through the return pipeline 2 to the economizer 5 , and then back into the boilers. Water in a closed loop (boiler, consumer, economizer, boiler) is moved by circulation pumps 6.

Rice. 5. : 1 - circulation pump; 2 - firebox; 3 - superheater; 4 - upper drum; 5 - water heater; 6 - air heater; 7 - chimney; 8 - centrifugal fan (smoke exhauster); 9 - fan for supplying air to the air heater

In fig. 6 shows a diagram of a boiler unit with a steam boiler having an upper drum 12. In the lower part of the boiler there is a furnace 3. For combustion of liquid or gaseous fuel, nozzles or burners 4 are used, through which the fuel, together with air, is fed into the furnace. The boiler is bounded by brick walls - lining 7.

When fuel is burned, the released heat heats the water to boiling in the tube screens 2 installed on the inner surface of the furnace 3 and ensures its transformation into water vapor.

Fig. 6.

Flue gases from the furnace enter the boiler gas ducts formed by the lining and special partitions installed in the bundles of pipes. When moving, the gases wash around the bundles of pipes of the boiler and superheater 11, pass through the economizer 5 and the air heater 6, where they are also cooled due to the transfer of heat to the water entering the boiler and the air supplied to the furnace. Then the significantly cooled flue gases are removed through the chimney 19 into the atmosphere by means of the smoke exhauster 17. Flue gases from the boiler can be discharged even without a smoke exhauster due to the natural draft generated by the chimney.

Water from the water supply source through the feed pipeline is supplied by pump 16 to the water economizer 5, from where, after heating, it enters the upper drum of the boiler 12. The filling of the boiler drum with water is controlled by a water indicator glass installed on the drum. In this case, the water evaporates, and the resulting steam is collected in the upper part of the upper drum 12. Then the steam enters the superheater 11, where it is completely dried due to the heat of the flue gases, and its temperature rises.

From the superheater 11, steam enters the main steam line 13 and from there to the consumer, and after use it condenses and in the form of hot water (condensate) returns back to the boiler room.

Losses of condensate at the consumer are replenished with water from a water supply system or from other sources of water supply. Before being fed into the boiler, the water is subjected to appropriate treatment.

The air required for fuel combustion is taken, as a rule, from the top of the boiler room and supplied by the fan 18 to the air heater 6, where it is heated and then sent to the furnace. In boilers of small capacity, air heaters are usually absent, and cold air is supplied to the furnace either by a fan or by vacuum in the furnace created by the chimney. Boiler plants are equipped with water treatment devices (not shown in the diagram), instrumentation and appropriate automation equipment, which ensures their uninterrupted and reliable operation.

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For the correct installation of all elements of the boiler room, a wiring diagram is used, an example of which is shown in Fig. nine.

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Hot water boilers are designed to produce hot water used for heating, hot water supply and other purposes.

To ensure normal operation, boiler rooms with hot water boilers are equipped with the necessary fittings, instrumentation and automation equipment.

A hot water boiler house has one heat carrier - water, in contrast to a steam boiler house, which has two heat carriers - water and steam. In this regard, a steam boiler room must have separate pipelines for steam and water, as well as tanks for collecting condensate. However, this does not mean that the schemes of hot water boiler houses are simpler than steam ones. Hot water and steam boilers are different in terms of the complexity of the device depending on the type of fuel used, the design of boilers, furnaces, etc. ... All of them are connected by common communications - pipelines, gas pipelines, etc.

The device of boilers of lower power is shown below in paragraph 4 of this topic. In order to better understand the structure and principles of operation of boilers of different capacities, it is advisable to compare the design of these less powerful boilers with the design of the boilers described above with a higher power, and find in them the main elements that perform the same functions, and also understand the main reasons for the differences in designs.

3. Classification of boiler units

Boilers as technical devices for the production of steam or hot water are distinguished by a variety of design forms, principles of operation, used types of fuel and performance indicators. But according to the method of organizing the movement of water and steam-water mixture, all boilers can be divided into the following two groups:

Natural circulation boilers;

Boilers with forced movement of the heat carrier (water, steam-water mixture).

In modern heating and heating-industrial boilers, boilers with natural circulation are mainly used for steam production, and for the production of hot water - boilers with forced movement of the coolant, operating on a direct-flow principle.

Modern steam boilers with natural circulation are made from vertical pipes located between two collectors (upper and lower drums). Their device is shown in the drawing in Fig. 10, a photograph of the upper and lower drums with pipes connecting them is shown in Fig. 11, and placement in the boiler room is shown in Fig. 12. One part of the pipes, called heated "riser pipes", is heated by the torch and the combustion products, while the other, usually unheated part of the pipes, is located outside the boiler unit and is called "downpipes". In the heated riser pipes, the water is heated to a boil, partially evaporates and in the form of a steam-water mixture enters the boiler drum, where it is separated into steam and water. Water from the upper drum enters the lower collector (drum) through the lowering unheated pipes.

The movement of the coolant in boilers with natural circulation is carried out due to the driving pressure created by the difference in the weights of the water column in the downcomer and the column of the steam-water mixture in the riser pipes.

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In steam boilers with multiple forced circulation, heating surfaces are made in the form of coils that form circulation circuits. The movement of water and steam-water mixture in such circuits is carried out using a circulation pump.

In once-through steam boilers, the circulation rate is one, i.e. When heated, feed water turns into a steam-water mixture, saturated and superheated steam.

In hot water boilers, when moving along the circulation circuit, water heats up in one revolution from the initial to the final temperature.

According to the type of heat carrier, boilers are divided into hot water and steam boilers. The main indicators of a hot water boiler are thermal power, that is, heating capacity, and water temperature; the main indicators of a steam boiler are steam capacity, pressure and temperature.

Hot water boilers, the purpose of which is to obtain hot water of specified parameters, are used to supply heat to heating and ventilation systems, domestic and technological consumers. Hot water boilers, which usually work according to the direct-flow principle with a constant water flow, are installed not only at CHPPs, but also in district heating, as well as heating and industrial boilers as the main source of heat supply.

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According to the relative movement of heat exchanging media (flue gases, water and steam), steam boilers (steam generators) can be divided into two groups: water-tube boilers and fire-tube boilers. In water-tube steam generators, water and a steam-water mixture move inside the pipes, and the flue gases wash the pipes outside. In Russia in the 20th century, Shukhov's water-tube boilers were mainly used. In a fire-tube, on the contrary, flue gases move inside the pipes, and water washes the pipes from the outside.

According to the principle of movement of water and steam-water mixture, steam generators are divided into units with natural circulation and with forced circulation. The latter are subdivided into direct-flow and multiple-forced circulation.

Examples of placement in boiler rooms of boilers of different power and purpose, as well as other equipment, are shown in Fig. 14-16.

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Rice. 16. Examples of placement of household boilers and other equipment

Auxiliary equipment of boiler plants is:

• electrical filters;
• air heaters;
• chimneys.

These elements are the main parts among the auxiliary equipment. They are installed above the boiler. The main and auxiliary equipment of the boiler room should be designed according to such technical schemes that will automate the control.

Boiler system installation and safety

During the construction of their own house, everyone carefully plans the interior, tries to carry out all the work and repairs with high quality, and, of course, the installation of the boiler. Boiler plant equipment is the most important step in achieving complete comfort in your own home. The installation of this system must be treated responsibly so as not to pay fines and alter anything in the future.

Work must be carried out under the strict supervision of a specialist to avoid both fires and explosions.

In order to avoid the repair of boiler equipment and serious consequences, a serious list of services from the installation and organization is provided. It all starts with the collection of documents and ends with the launch of the heating system for use. In order for the operation of the boiler and the entire system to run smoothly, reliably and economically, all services for the use of the installation and commissioning of boiler equipment must be carried out by a highly qualified specialist. He must have a license and permission to carry out such work.

1. The piping of the entire heating system is preliminarily carried out.
2. Checking for the correct operation of the entire system, in order to avoid the repair of boiler equipment and accidents.
3. Carrying out the final setting of equipment for the boiler room.
4. Receiving instruction from specialists.

System maintenance

If the installation, adjustment of the boiler equipment and the boiler was carried out in accordance with all the rules and regulations, during use, situations may nevertheless arise that will require additional repair of the auxiliary equipment of the boiler plant. The most common cause of such breakdowns is poor-quality water, which does not meet the standards for boiler equipment. The adjustment of the boiler, repairs, related work, is quite an expenditure matter.

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In order to reduce the cost of repairing boiler rooms and boiler equipment in the future, the construction of the heating system should be carried out by companies that have a wide range of services:

• Post-warranty service of the constructed object.
• Reconstruction.
• Necessary repairs and adjustments.

The main task of the owner is to carry out timely maintenance of the premises for the boiler room.

The main (Fig. 1) and auxiliary elements of the heating system

A boiler room is a complex of devices that is completely ready to convert the chemical energy of the fuel into thermal hot energy, or steam of the required parameters.

The boiler equipment manufacturer offers the following basic components:

• water economizer;
• air heater;
• frame with ladders and service shelves;
• frame;
• thermal insulation;
• sheathing;
• fittings;
• headset;
• gas ducts.

Equipment for the boiler room (needs adjustment) has additional installations of any manufacturer:

• fans;
• smoke exhausters;
• feed, feed and circulation pumps;
• water treatment plants;
• fuel transfer systems;
• installation for collecting ash;
• vacuum ash remover.

Boiler equipment manufacturers have developed the main plant in the fuel oil sector during the combustion of gas, a gas control point or a gas control plant.

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The adjustment of the entire heating system, the commissioning process is the guarantee of smooth operation and everyone's comfort.

1. Steam boiler installation. This is a device that consists of a firebox, evaporating surfaces. Its main job is to evaporate steam that was used outside the device. Incorrect adjustment of the process provokes, under pressure, which is higher than the atmospheric heat account and is released during the combustion of fuel, steam out of the boiler.
2. Water heating boiler. This is a heat exchange device in which water is the main source of thermal energy.
3. Furnace device. The operation of this unit in combustion of fuel, converting its energy into heat.
4. Boiler lining. This system is provided by manufacturers in order to perform work to reduce heat losses, ensure gas density.
5. Kazan. This is a metal structure. Its main work is to hold the boiler and individual loads, to ensure the necessary mutual placement of the boiler elements.
6. Steam superheater. This device increases the steam temperature above the saturation temperature of the pressure in the boiler. The manufacturer has provided for the operation of this system of coils, where the complete adjustment of the boiler equipment implies connection at the inlet of saturated steam to the boiler drum, and at the outlet to the superheated steam chamber.
7. Water economizer. The essence of the operation of this device lies in its heating by the products of fuel combustion, which, in turn, partially heats up or completely evaporates the water in the boiler.
8. Air heater. Its main work is to heat the air with fuel combustion products before the fuel enters the boiler furnace.

The need for repairs during the warranty period

Parts for the boiler may be needed even while the unit is still under warranty.

Repair of boiler equipment is possible:

• the boiler installation work has been done incorrectly;
• the use of the unit is not correct;
• maintenance is carried out at the wrong time;
• voltage drops (you can purchase a stabilizer that will eliminate this problem);
• poor quality coolant (on the inlet pipeline, you can install it as a filter for the boiler).

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To avoid the repair of boiler equipment, all the nuances should be thought out in advance, rather than urgently solving the problem.

Breaking? Don't panic

Of course, if the repair of boiler equipment is needed before the heating season, then this is half the trouble, and if in the midst of cold weather, the main thing is not to panic. But you also need to take the problem seriously, because the adjustment of the boiler and the entire system can get lost. If the breakdown of the unit is not serious, you can make the repair yourself. But if there are doubts about the causes and consequences, the repair should be entrusted to a professional.

The successful operation of the installation depends not only on the manufacturer, but also on the choice of the model while still in the store. It depends on the choice whether the unit will cope with the tasks and the volume of work - the entire commissioning process. It is better if the company that made the sale had a service center somewhere nearby. So that at any time she could help with the commissioning process, she inspected and repaired the boiler (Figure 2).

Of course, the manufacturer of boiler equipment is responsible for its goods, but the owner must operate according to the instructions and rules so that there are no failures in setting up the installation and waste on repairs. The statistics of companies for the repair of boilers and heating systems claim that almost 70% of the causes of breakdowns are due to improper use and operation of devices, violation of requirements and standards. Therefore, the repair of boiler equipment happens mainly due to the fault not of the manufacturer, but of the consumer.

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Device adjustment and repair

If a person does not understand repair issues, then it will be difficult for him to understand this process with boilers and devices for it.

The list contains the most common problems:

• Electronic board. The manufacturer has given this device responsibility for all processes. It regulates the device, turns it on and off, controls, influences the commissioning process. A minor malfunction will result in an explosion. In order to avoid breakdowns, it is better to mount such an element as a voltage stabilizer.
• (Figure 3). If the sale of boiler equipment was carried out with a defect from the manufacturer, more than one commissioning process will not help. The problem with the operation of the installations arises in the first months of operation. To eliminate the drawback, you will have to completely replace the heat exchanger. But the problem of clogging the passage with various deposits and salts is much more common. The coolant flow begins to decrease, and one day the boiler starts to boil. In order to avoid repairs and commissioning, attention must be paid to the quality of the water. And also, during the sale of the unit, pay attention to its quality, whether there is any defect from the manufacturer.
• (Figure 4). The commissioning process of the installation assumes the continuous operation of this pump. But if it turns off, the boiler will boil. The unit shuts down thanks to the safety thermostat (commercially available). But the problem will not disappear and the repair is guaranteed. The fault in the breakdown is the coolant - liquid for heating boilers. The pump can stop for two reasons: the appearance of scale; increased debris in the middle of the case. To avoid this trouble, there is a special filter on sale that is installed on the inlet pipe.
• Gas automatics. Repair of this boiler element is practically impossible. Usually, this component is completely changed. In order to avoid the next adjustment of the boiler, it is better to prevent this breakdown than to solve it. There are poor quality fuels on sale. Therefore, in order to prevent the breakdown of gas automatics, it is worth buying high quality fuel and using clean water for the coolant.

Today there are many outlets that offer components for boilers. It is worth noting that well-known branded, popular companies' details are always recommended by professionals. They are of high quality, have a simple commissioning process, the boiler is set up quickly enough.

Control and measuring devices (instrumentation)- instruments for measuring pressure, temperature, flow rate of various media, liquid level and gas composition, as well as safety devices installed in the boiler room.

Measuring device- technical means of measurement, providing the generation of a signal of measurement information in a form convenient for the observer.

Distinguish between indicating and self-recording indicator devices. The devices are characterized by the range, sensitivity and measurement error.

Instruments for measuring pressure. Pressure is measured with manometers, traction gauges (low pressure and vacuum), barometers and aneroids (atmospheric pressure). Measurements are made using the phenomenon of deformation of elastic elements, changes in the levels of a liquid, which is affected by pressure, etc.

Deformation-type manometers and draft gauges contain an elastic element (bent hollow springs or flat diaphragms or diaphragm boxes) moving under the action of the medium pressure transmitted from the measuring probe to the internal cavity of the element through the fitting. The movement of the elastic element is transmitted through a system of rods, levers and gearing to the arrow, which fixes the measured value on the scale. Manometers are connected to water pipelines by means of a straight fitting, and to steam pipelines by means of a curved siphon tube (condenser). A three-way valve is installed between the siphon tube and the manometer, which allows the manometer to communicate with the atmosphere (the arrow will show zero) and purge the siphon tube.

Liquid manometers are made in the form of transparent (glass) tubes, partially filled with liquid (tinted alcohol) and connected to pressure sources (vessel-atmosphere). Tubes can be installed vertically (U-shaped gauge) or obliquely (micromanometer). The magnitude of the pressure is judged by the movement of the liquid levels in the tubes.

Instruments for measuring temperature. Temperature measurement is carried out using liquid, thermoelectric thermometers, optical pyrometers, resistance thermometers, etc.

In liquid thermometers, under the action of a heat flux, the heated (cooled) liquid expands (contracts) inside a sealed glass tube. Most often, the following are used as a filling liquid: mercury from -35 to +600 0 С and alcohol from -80 to +60 0 С. in a metal case and isolated from it. When heating (cooling), an electromotive force (EMF) appears at the junction of thermoelectrodes (in the junction) and a potential difference appears at the free ends - a voltage that is measured by a secondary device. Depending on the level of the measured temperatures, thermocouples are used: platinum-rhodium - platinum (PP) - from -20 to +1300 0 С, chromel-alumel (HA) - from -50 to +1000 0 С, chromel-copel (HC) - from - 50 to +600 0 С and copper - constantan (MC) - from -200 to +200 0 С.

The principle of operation of optical pyrometers is based on comparing the luminosity of the measured object (for example, a flame of burning fuel) with the luminosity of a filament heated from a current source. They are used to measure high temperatures (up to 6000 0 С).

A resistance thermometer works on the principle of measuring the electrical resistance of a sensitive element (a thin wire wound on a frame or a semiconductor rod) under the action of a heat flux. Platinum (from -200 to +75 0 C) and copper (from -50 to +180 0 C) are used as wire resistance thermometers; in semiconductor thermometers (thermistors), copper-manganese (from -70 to +120 0 C) and cobalt - manganese (from -70 to +180 0 C) sensitive elements are used.

Instruments for measuring flow. The measurement of the flow rate of liquid or gas in the boiler room is carried out either by throttling or summing devices.

A throttle flowmeter with variable pressure drop consists of a diaphragm, which is a thin disk (washer) with a cylindrical hole, the center of which coincides with the center of the pipeline cross-section, a pressure drop meter and connecting pipes.

The totalizing device determines the flow rate of the medium according to the speed of rotation of the impeller or rotor installed in the housing or impeller.

Instruments for measuring liquid level. Water indicating devices (glass) are designed for constant monitoring of the position of the water level in the upper drum of the boiler unit.

For this purpose, at least two water-indicating devices of direct action with flat, smooth or corrugated glasses are installed on the latter. At a boiler unit height of more than 6 m, reduced remote water level indicators are also installed.

Safety devices - u devices automatically stop the supply of fuel to the burners when the water level drops below the permissible level. In addition, steam and hot water boiler units operating on gaseous fuel, when air is supplied to the burners from blowing fans, are equipped with devices that automatically stop the gas supply to the burners when the air pressure drops below the allowable value.

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The development of a project for the automation of boiler houses is carried out on the basis of a task drawn up during the implementation of the heat engineering part of the project. The general tasks of monitoring and controlling the operation of any power plant is to ensure:

Generation at each moment of the required amount of heat at certain pressure and temperature parameters;

Efficiency of fuel combustion, rational use of electricity for the plant's own needs and reduction of heat losses to a minimum;

Reliability and safety, i.e. the establishment and maintenance of normal operating conditions for each unit, excluding the possibility of malfunctions and accidents, both of the unit itself and of auxiliary equipment.

Based on the tasks and instructions listed above, all control devices can be divided into five groups intended for measurement:

1. Consumption of water, fuel, air and flue gases.

2. Pressure of water, gas, air, measurement of vacuum in the elements and gas ducts of the boiler and auxiliary equipment.

3. Temperatures of water, air and flue gases

4. The level of water in tanks, deaerators and other containers.

5. The qualitative composition of gases and water.

Secondary devices can be indicating, registering and summing. To reduce the number of secondary devices on the heat shield, some of the values ​​are collected on one device using switches; for critical quantities on the secondary device, the maximum permissible values ​​are marked with a red line, they are measured continuously.

In addition to the devices brought out by the control panel, local installation of instrumentation is often used: thermometers for measuring water temperatures; pressure gauges; various traction meters and gas analyzers.

The combustion process in the KV-TS-20 boiler is regulated by three regulators: a heat load regulator, an air regulator and a vacuum regulator.

The heat load regulator receives a command impulse from the main correcting regulator, as well as impulses for the water flow rate. The heat load regulator acts on the body that regulates the fuel supply to the furnace.

The common air regulator maintains the fuel-to-air ratio by receiving pulses based on the fuel consumption from the sensor and from the pressure drop across the air heater.

Constant vacuum in the firebox is maintained by means of a regulator in the boiler firebox and a smoke exhauster acting on the guide vanes. There is a dynamic connection between the air regulator and the vacuum regulator, the task of which is to supply an additional impulse in transient modes, which allows maintaining the correct draft mode during the actuation of the air regulator and the vacuum.

The dynamic coupling device has a directional action, i.e. only a vacuum regulator can be a slave regulator.

Power regulators are installed to monitor the flow of network and feed water.

Expansion thermometer mercury:

Industrial mercury thermometers are manufactured with an enclosed scale and, according to the shape of the lower part with a reservoir, there are straight lines of type A and angular type B, bent at an angle of 90є in the direction opposite to the scale. When measuring the temperature, the lower part of the thermometers completely sinks into the measured medium, i.e. their immersion depth is constant.

Expansion thermometers are indicating devices located at the point of measurement. Their principle of operation is based on the thermal expansion of a liquid in a glass tank, depending on the measured temperature.

Thermoelectric thermometer:

To measure high temperatures with remote transmission of readings, thermoelectric thermometers are used, the operation of which is based on the principle of the thermoelectric effect. Chromel - copel thermoelectric thermometers develop thermo - emf, significantly higher than the thermo - emf of other standard thermoelectric thermometers. The range of application of chromel - copel thermoelectric thermometers is from - 50є to + 600є С. The diameter of electrodes is from 0.7 to 3.2 mm.

Tubular - spring pressure gauge:

The most widespread use for measuring the overpressure of liquid, gas and vapor are manometers with a simple and reliable design, clear indications and small dimensions. The significant advantages of these devices are also a large measurement range, the possibility of automatic recording and remote transmission of readings.

The principle of operation of a deformation manometer is based on the use of deformation of an elastic sensitive element, which occurs under the influence of the measured pressure.

A very common type of deformation devices used to determine overpressure are tubular - spring pressure gauges, which play an extremely important role in technical measurements. These devices are made with a single-turn tubular spring, which is a metal elastic tube of oval cross-section bent around the circumference.

One end of the spiral spring is connected to a gear, and the other is fixed to a stand that supports the transmission mechanism.

Under the action of the measured pressure, the tubular spring partially unwinds and pulls the leash, which drives the gear-sector mechanism and the pressure gauge needle moving along the scale. The pressure gauge has a uniform circular scale with a central angle of 270 - 300є.

Automatic potentiometer:

The main feature of the potentiometer is that the thermoelectric power developed by the thermoelectric thermometer is in it. etc. with. is balanced (compensated) by an equal in magnitude, but opposite in sign voltage from a current source located in the device, which is then measured with great accuracy.

Automatic small-sized potentiometer KSP2 - indicating and recording device with a linear scale length and a chart tape width of 160 mm. The basic error of the instrument readings is ± 0.5% and the recording error is ± 0.1%.

The variation in readings does not exceed half of the basic error. The speed of the chart tape can be 20, 40, 60, 120, 240 or 600, 1200, 2400 mm / h.

The potentiometer is powered by 220 V AC, 50 Hz. The power consumed by the device is 30 VA. Changing the supply voltage by ± 10% of the nominal does not affect the readings of the device. The admissible value of the ambient temperature is 5 - 50єС and the relative humidity is 30 - 80%. The dimensions of the potonceometer are 240 x 320 x 450 mm. and a weight of 17 kg.

It is recommended to install deformation electric pressure gauges near the pressure take-off point, fixing vertically with the nipple down. For pressure gauges, the ambient air can have a temperature of 5 - 60 ° C and a relative humidity of 30 - 95%. They must be away from powerful sources of alternating magnetic fields (electric motors, transformers, etc.)

The pressure gauge contains a tubular spring 1, fixed in the holder 2 by means of a sleeve 3. To the free end of the spring, a magnetic plunger 5 is suspended on a lever 4, located in a magnetomodulation transducer 6 sitting on the holder 6. Next to the latter, an amplifying device 7 is fixed on a folding bracket.

The device is enclosed in a steel case 8 with a protective casing 9, adapted for flush mounting. The pressure gauge is connected to the measured pressure using a holder fitting, and the connecting wires are connected through a terminal box 10. The pressure gauge is equipped with a zero corrector 11. The device dimensions are 212 x 240 x 190 mm. and a weight of 4.5 kg.

MPE type manometers can be used with one or more secondary DC devices: automatic electronic indicating and self-recording milliammeters of the KSU4, KSU3 types,

KSU2, KSU1, KPU1 AND KVU1, calibrated in pressure units, magnetoelectric indicating and self-recording milliammeters of types Н340 and Н349, central control machines, etc. Automatic electronic DC milliammeters differ from the corresponding automatic potentiometers only by a calibrated load resistor connected in parallel to the input, voltage drop across which from the flowing current of the manometer is the measured value.

Magnetoelectric milliammeters of the H340 and H349 types have a scale and bar width of 100 mm. accuracy class of the device 1.5. The chart tape is set in motion at a speed of 20 - 5400 mm / h from a synchronous micromotor powered from an alternating current voltage of 127 or 220 V, with a frequency of 50 Hz.

The dimensions of the device are 160 x 160 x 245 mm. and a weight of 5 kg.

Direct acting regulator:

An example of a direct acting regulator is a control valve.

The valve consists of a cast-iron body 1, closed at the bottom by a flange cover 2, which closes the opening for draining the medium filling the valve and for cleaning the valve. 3 stainless steel seats are screwed into the valve body. Plunger 4 sits on the seats. The working surfaces of the plunger are lapped to the seats 3. The plunger is connected to the stem 6, which can raise and lower the plunger. The stem runs in the stuffing box. The gland seals the cover 7, which is attached to the valve body. To lubricate the rubbing surfaces of the stem, oil is supplied to the stuffing box device from an oiler 5. The valve is controlled by a membrane-lever device, consisting of a yoke 8, a membrane head 13, a lever 1 and weights 16,17. In the diaphragm head, between the upper and lower cups, a rubber membrane 15 is clamped, resting on a plate 14, seated on the rod 9 of the yoke. A rod 6 is fixed in the rod 9. The rod of the yoke has a prism 12 on which the lever 11 rests, rotating on a prismatic support 10 fixed in the yoke 8.

There is a hole in the upper shell of the diaphragm head, in which the impulse tube is fixed, which delivers a pressure pulse to the diaphragm. Under the influence of the increased pressure, the membrane bends and drags the plate 14 and the rod of the yoke 9 down. The reinforcement developed by the membrane is balanced by weights 16 and 17 suspended from the lever. Weights 17 are used for coarse adjustment of the set pressure. With the help of weight 16, moving along the lever, a more accurate valve adjustment is made.

The pressure is transferred directly to the diaphragm head by the controlled medium.

Actuating mechanism:

Regulatory bodies are used to regulate the flow of liquid, gas or steam in the process. The movement of regulatory bodies is carried out by actuators.

Regulatory bodies and actuators can be in the form of two separate units, interconnected by means of levers or cables, or in the form of a complete device, where the regulatory body is rigidly connected to the actuator and forms a monoblock.

The actuator, receiving a command from the regulator or from a command apparatus controlled by a person, transforms this command into a mechanical movement of the regulating body.

The mechanism is electric, single-turn, designed to move regulating bodies in relay control and remote control systems. The mechanism accepts an electrical command, which is a three-phase mains voltage of 220 or 380 V. The command can be given using a magnetic contact starter.

The actuator consists of an electric motor part

I - servo drives and control columns, II servo block. The servo drive consists of a three-phase asynchronous reversible motor 3 with a squirrel-cage rotor. From the motor shaft, the torque is transmitted to the gearbox 4, which consists of two stages of a worm gear. Lever 2 is mounted on the input shaft of the gearbox, which is articulated with the regulating body by means of a rod.

Turning the handwheel 1, with manual control, you can turn the gearbox output shaft without the help of an electric motor. When the flywheel is manually operated, the mechanical transmission from the electric motor to the flywheel is decoupled.

The regulating body is designed to change the flow rate of the controlled medium, energy or any other values ​​in accordance with the requirements of the technology.

In poppet valves, the blocking and throttling surface is flat. For a valve with plug-type smooth working surfaces, the characteristic is linear, that is, the capacity of the valve is directly proportional to the stroke of the plunger.

Regulation is carried out by changing the flow area by translational movement of the spindle when the flywheel rotates using a lever articulated through a rod with an electric actuator.

Valves cannot serve as shut-off bodies.

Control starter:

Starters PMTR - 69 are based on magnetic reversible contacts, each of which has three normally open power contacts included in the motor power supply circuit. In addition, the starting device has a braking device made on the basis of an electric capacitor and connected via break contacts to one of the stator windings of the electric motor. When any group of power contacts is closed, auxiliary contacts open and the capacitor is disconnected from the electric motor, moving by inertia, interacts with the residual magnetic field of the stator and induces an emf in its windings.

The auxiliary contacts, closing the circuit of the stator winding of the capacitor, create their own magnetic field of the rotor and stator in the stator and cause a braking effect that counteracts rotation, which prevents the actuator from running out. The main disadvantage of starters is their low reliability (burning of contacts, short circuit).

The block has three current and one voltage inputs. Block R - 12 consists of the main units: input circuits VKhTs, DC amplifiers UPT 1 and UPT 2, block MO limiting, while UPT 2 allows you to receive at the output one current signal and an additional voltage signal. Block R - 12 receives power from the power supply unit, which receives an additional signal from the control unit CU.

The signal from the sensor goes to the input circuits node, where the driver signal I zu is also fed. Further, the mismatch signal y goes to the DC amplifier UPT 1, passing through the adder, where mismatch signals from the input circuits and feedback are generated. The block for limiting the OM signal ensures its further transformation, limiting the signal to minimum and maximum. The amplifier UPT 2 is the final amplification unit. The MD feedback unit receives a signal from the output of the UPT 2 amplifier and ensures smooth switching of circuits from manual control to automatic control. The MD feedback unit provides the formation of a control signal in accordance with the P -, PI - or PID control laws.

Technological protection.

To avoid emergency modes, equipment control systems with excessive deviations of parameters and to ensure operational safety are equipped with technological protection devices.

Depending on the results of the impact on the equipment, the protection is subdivided: into units that stop or shut down; transferring equipment to the mode of reduced loads; performing local operations and switching; preventing emergencies.

Protection devices must be reliable in pre-emergency and emergency situations, i.e., there must be no failures or false positives in the actions of the protection. Failures in protection actions lead to untimely shutdown of the equipment and further development of the accident, and false alarms take the equipment out of the normal technological cycle, which reduces the efficiency of its operation. To meet these requirements, highly reliable devices and devices are used, as well as appropriate construction of protection circuits.

The protection includes sources of discrete information sensors, contact devices, auxiliary contacts, logic elements and a relay control circuit. The actuation of the protections should ensure the unambiguity of the action, while the transfer of the equipment to the operating mode after its protection is carried out after checking and eliminating the causes that caused the actuation.

When designing thermal protections for boilers, turbines and other thermal equipment, the so-called priority of the protection action is provided, that is, first of all, the operations for the one of the protections that cause a large degree of unloading are performed. All protections have independent power sources and the ability to fix the causes of operation, as well as light and sound alarms.

Technological signaling.

General information about the alarm.

The technological alarm included in the control system is designed to alert the operating personnel about unacceptable deviations in the parameters and operating mode of the equipment.

Depending on the requirements for signaling, it can be conditionally divided into several types: signaling, which ensures the reliability and safety of the equipment; alarm, fixing the operation of equipment protection and the reasons for the operation; alarm signaling about unacceptable deviations of the main parameters and requiring an immediate shutdown of the equipment; signaling of power supply failure of various equipment and apparatus.

All signals are sent to the light and sound devices of the block control panel. There are two types of sound signaling: warning (bell) and emergency (siren).

Light alarms are made in a two-color version (red or green lamps) or with the help of luminous boards, which indicate the reason for the alarm.

Newly received signals against the background of those already controlled by the operator can go unnoticed, therefore the signaling circuits are built so that the new signal is highlighted by blinking.

Functional diagram of the alarm device.

The signaling circuit is powered by a DC power supply, which increases their reliability. The signal for switching on the CB alarm is fed to the relay interrupt block of the PDU signal, and then in parallel to the ST light board and the sound memory device. At the same time, in the PDU, the circuit is made in such a way that it provides an intermittent glow on the display and a constant sound signal.

After receiving the signal and removing the sound, the circuit must be ready to receive the next signal, regardless of whether the signaling parameter has returned to its nominal value.

Each light signal must be accompanied by an audible signal to attract the attention of the operating personnel.

Signaling means.

Electronic contact pressure gauge.

To measure and signal pressure, an EKM type manometer with a tubular spring is used. The pressure gauge has a housing with a diameter of 160 mm. with rear flange and radial union. The device contains an arrow 1 that sets signal arrows 2 and 3 (minimum and maximum), set to the set pressure values ​​using a key. Box 4 with clamps for connecting the signaling circuit to the device. The pressure gauge mechanism is enclosed in a housing 5. The device communicates with the measured medium through the nozzle 6.

Upon reaching any of the preset side-to-side pressures, the contact associated with the pointer arrow comes into contact with the contact located on the corresponding signal arrow and closes the signaling circuit. The contact device is powered by a direct or alternating current network, with a voltage of 220 V.

Modern heat power engineering cannot be imagined without high-precision measuring instruments. The technological process at power facilities must be constantly monitored using sensors or converters, which not only passively remove information, but also allow automatic adjustment and protective shutdown in case of violation of the normal mode.

Types of instrumentation in the boiler room

From the general name and the above, we can conclude that the following complexes are necessary for the trouble-free operation of gas equipment:

• measuring;
• adjusting;
• protective.

The operation of water heating and power plants without protective devices is prohibited, since in case of non-standard situations and breakdowns, the threat to human life and the integrity of mechanisms increases many times over. Before firing up, the personnel on duty organizes a check of the effect of the protections on stopping the boiler. The introduction of this clause in the PTE helped to seriously reduce the negative consequences of accidents.

Features of the operation of instrumentation and automation of boiler equipment

For network and gas pipelines, both remote digital complexes and mechanical devices are envisaged. This allows the maintenance personnel to monitor the state of the environment during a bypass of the boiler room or in case of loss of voltage. The action of the protections applies most often to the fuel supply, to exclude an explosion in case of violations of the combustion regime in boilers.

Maintenance of instrumentation in boiler rooms

For the correct operation of control devices at heat power facilities, a special workshop or subdivision is formed. This service performs the following functions:

• daily control of the correctness of the readings,
• checking protection devices;
• repair and replacement of out-of-order devices;
• periodic verification of measuring devices.

Maintaining the boiler unit mode is impossible without constant monitoring by the boiler room operator. Several rounds per shift help keep such measuring equipment in good working order.

Instrumentation devices for boiler rooms

The main measuring devices in gas boilers are:

• Manometers. They are necessary to control the pressure in pipelines; without them, operation is often impossible. According to them, the combustion process in hot water and power boilers is regulated by measuring the pressures of natural gas and air.
• Thermocouples. The coolant must be dispensed into the city at a certain temperature. To control it, and therefore the operating mode of the boiler room, several thermal converters are installed.
• Flowmeters. The economic characteristics of the production of heat and electrical energy are related to the consumption of the working medium and fuel. Digital writing devices are used to measure them.

Locksmith of instrumentation and automation of gas boiler houses

In modern production, all parameters obtained from measuring instruments are accumulated at the point. Computer systems on it allow you to refer to this information, up to a certain period. This order is useful for analysis.

The duties of the locksmith on duty include general points:

• ensuring the serviceability of control and protection devices;
• periodic check of measuring devices;
• instrumentation maintenance in the boiler room;
• accumulation and provision of complete information on the parameters of the production process.

Operational personnel in shifts ensure the normal operation of measuring complexes at power facilities and heating networks. He also controls the information collection system in order to prevent it from failing.