Manual. Burner gas infrared radiation. The use of infrared burners for heating
Ticket 22.
- The device, the principle of operation of infrared burners. Advantages and disadvantages.
- Marking stop valves.
- Requirements of the Rules for the placement of an individual gas-cylinder installation.
- The device, the appointment of cases when laying gas pipelines.
Infrared gas burner: working principle and advantages
An infrared gas burner is a fairly safe, efficient and relatively inexpensive device. These burners are great for heating work and domestic premises, warming up and cooking, they can be used outdoors and anywhere where ventilation works well.
Gas infrared radiation burners currently on sale have either a ceramic or metal emitter, the heating temperature of which reaches 600 - 900 ° C.
Advantages of infrared gas burners compared to lamp, tubular or spiral heaters
Depending on the type and model of the burner, they have significant advantages:
- safety: lamp burners can burst and clog the heated surface with fragments, while with gas infrared burners this will not happen;
- efficiency: compared to electric heaters, the radiation density of infrared is higher, so you can use a smaller emitter surface and get the same effect;
- burners such as Solarogaz, Prometheus or Sibiryachka heat more evenly;
- such devices are autonomous and can be used on a hike, on winter fishing, in the country, as they do not depend on the presence or absence of electricity;
- In ceramic infrared gas burners there is no open flame, so they are not afraid of the wind, and they are more fireproof.
How infrared gas burners work
Devices currently being produced work according to one of two schemes:
- or a combustible gas-air mixture burns in the pores ceramic tiles(radiator), which causes heating of this tile and radiation of heat into space;
- or, in the case of a metal radiator, the metal sheets are heated from the outside by small gas flares or by a stream of hot exhaust gases.
Since combustion occurs in the pores, and the temperature that the device is capable of producing is higher, gas infrared radiation burners with a ceramic emitter are safer and “warmer” than metal ones.
The principle of operation of gas infrared burners (Fig. 8.18.) is as follows. Gas under pressure through a nozzle is fed into the mixer, injecting the air necessary for combustion along the way. The gas-air mixture formed in the mixer, passing through the holes of the ceramic nozzle (emitter), burns out without a visible flame on the outer surface. The ceramic nozzle, heated up to a temperature of 800-900 degrees C, is a source of infrared radiation.
Fig.8.18 Infrared gas burner.
1- case; 2- distribution chamber; 3- gas-air mixer; 4- overlay; 5 - nozzle; 6- nipple; 7- fitting; 8- emitter; 9- grid.
Rebar marking.
The following data is indicated on the valve body:
1. Conditional pressure;
2. Nominal diameter;
3. Trademark of the manufacturer;
4. Nominal diameter;
5. Arrow indicating the direction of fluid flow.
Depending on the material of the valve body, it is painted in different colors:
1. Carbon steel (gray);
2. Alloy steel (blue);
3. Acid-resistant stainless steel (blue);
4. Gray malleable cast iron (black);
5. Non-ferrous alloys (not painted).
An individual gas-cylinder installation consists offrom a gas appliance, gas pipeline, gas reducer, cylinder with liquefied gas, a metal cabinet (if gas cylinders are installed outdoors) and a shut-off device in front of the gas appliance (when cylinders are installed outdoors). Cylinders of individual liquefied gas installations can be installed both indoors and outdoors.
In the first case, when placing cylinders inside the building, it is allowed to install only one cylinder with a capacity of not more than 80 liters; it is usually installed in the room where the gas appliance is located. The cylinder is attached to the wall with a metal clamp or a special belt in a place accessible for inspection and replacement. The distance from the cylinder to the gas appliance must be at least 1.5 m and up to heating appliances- not less than 1 m. It can be reduced to 0.5 m, provided that a wooden screen measuring 100X50 cm, upholstered sheet metal for asbestos; this screen protects the cylinder from heating. In this case, the distance from the cylinder to the screen must be at least 100 mm. Install cylinders against furnace doors heating stoves and slabs closer than 2 m are not allowed. When placing a cylinder for one gas appliance, a shut-off device is not installed in front of the appliance.
When supplying consumers with liquefied gas from cylinder installations located outside the building, disconnecting devices are installed in front of each device.
Cylinders outside the building are installed in a metal cabinet on the bases provided for by the project, and fastened to the wall of the building with metal brackets or clamps. The cabinet is a simple metal structure with two doors. Ventilation slots are made in the upper part of each door and in the lower part of the side walls of the cabinet. Inside the cabinet there are nests for installing cylinders and mounting the gearbox.
infrared gas-burners- this is an excellent choice for heating a private greenhouse, garage or hangar. In the common people, such devices are also called "sun models" because of their characteristic sunny shade of the working surface when turned on. Gradually, the use of infrared gas burners is becoming more and more popular, and soon these devices will completely replace the use of conventional fireplaces and convectors. What is special about infrared gas burners and what are their advantages?
difference
The main feature of these devices, which distinguishes the IR burner from all other "brothers", is the method of heating. Specifically, in these devices, the process of heat transfer occurs through rays invisible to the human eye. Thanks to this feature, all the heat that infrared gas burners create passes through the air to all nearby objects, and the temperature of the entire room will rise from their heating. Thus, when using IR devices, you will not experience a feeling of stuffiness, since, first of all, the rays do not heat the air, but the floor, walls and all other objects. Ultimately, the energy from the heated floor and wall will be transmitted over the entire area of the room, and the heat transfer process itself takes place in a matter of minutes. In fact, gas stove with infrared burners, including infrared heaters, are the fastest among all other similar devices.
Advantages
Of course, the main advantage when using such tools is their speed of action and ease of heating the room. Even the coldest room can turn into a full-fledged living space with a room temperature of +24 degrees Celsius in a matter of minutes. The maximum amount you need to spend to raise the temperature in the building by 15 degrees is 17-20 minutes.
At the same time, after heating the room, there is no excessive air circulation in the room, which can lead to the formation of dust with a high concentration of contaminants. This will be especially appreciated by people with hypersensitivity to allergies. In addition, after heating, a gas stove with infrared burners does not leave the effect of the smell of burnt dust, since the device does not act to increase the temperature in the air, but directly to increase the heating of the room itself.
Material
Most often, infrared gas burners consist of ceramic emitters. Thanks to the use of this material, the reliability of this heating device and, of course, the quality of work are significantly increased.
Price
The cost of these devices is relatively low and even very affordable, if we compare its price against the background of what we get as a result. For example, the Prometheus infrared gas burner costs about 800-900 rubles on the Russian market. A whole gas stove with a set of such devices costs about 3-4 thousand rubles.
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Mobile infrared gas ceramic heaters Prometheus are designed to work on main or bottled gas. The model is especially popular among lovers of fishing and hunting.
The device and principle of operation of the Prometheus burner
The gas burner-heater of infrared radiation Prometheus is manufactured using components manufactured by Rauschert Techische Keramik. High-quality assembly ensures the durability of the device, the uniformity of the spread of the flame, and complete safety of operation.How does the Prometheus burner work?
- Gas from a cylinder or line enters a special gas-air mixer. Combustible gas is mixed with air in the block.
- The gas-air mixture enters the next chamber connected to the ceramic panel. When the required pressure is reached, the mixture enters the holes of the emitter.
- Inside ceramic panel mixture is preheated and oxidized. Burning takes place with minimal emission of harmful substances.
- After 3-4 minutes, the portable gas infrared heater of the Prometheus brand reaches its operating power and begins to heat the room.
A distinctive feature of the Prometheus burner is the complete absence of flashing during gas ignition. Combustion takes place inside the ceramic emitter, which ensures complete safety of operation.
Where are IR heating devices Prometheus used?
IR heating devices Prometheus are used to quickly heat unheated rooms. The weight of the device is only 2.5 kg, which allows you to quickly transfer the installation if necessary. The performance of the installation of 3.8 kW is enough to quickly warm up the room.Most often, heaters are used in the following cases:
- For fishing - the heater is easy to install in a tent or outdoors. After turning on the unit, after a few minutes you can dry your clothes, gear, warm up if necessary, warm up and start the engine.
- In a greenhouse, a special device of a ceramic burner allows you to burn gas, practically without reducing humidity and without drying the air in the room.
- In a tent - gas combustion is carried out inside a ceramic emitter, there is no open fire, so you can install the emitter directly in the tent and provide comfortable conditions for overnight stay.
The work of one autonomous infrared gas heater Prometheus will be enough to maintain the necessary temperature regime in a large dugout, or hut.
Rules for the operation of the Prometheus heater
Gas infrared ceramic portable heater for tents Prometheus is connected to cylinders with compressed gas or a main pipe. During operation, the exhaust gas system is not used.To start the installation, do the following:
- Open the gas valve.
- Wait until the gas-air mixture enters the burner.
- Ignite the gas with a match.
During operation, it is necessary to ventilate the heated room. To operate at full power for 8.5 hours, the device needs 5 liters of gas. When connected to a standard cylinder with a capacity of 50 liters, the unit will operate continuously for about 90 hours.
Infrared emitter Prometheus, powered by gas, is the optimal solution in cases where a mobile heater is needed for going out into nature or heating uninsulated rooms.
The safety of the device, low operating costs and low weight of the emitter make it almost indispensable.
Calculation of power and temperature of a warm water floor
Heating with burners of infrared (radiant) radiation differs from the usual one in that the necessary heat is mainly supplied to the consumer directly by radiation. The energy from the nozzles of the burners propagates as light rays and is absorbed by the irradiated objects, which leads to their heating. Although the air temperature may be lower than with convective heating, conditions are created under which a person gives in environment no more heat than it receives and releases, i.e., conditions for thermal comfort are created. This allows using gas infrared burners to heat such rooms and sites for which the use of conventional (convective) heating systems not economically feasible or technically feasible.
Such facilities include industrial workshops with large heat losses, open installation and assembly sites, outdoor sports stands, swimming pools, exhibitions, shop windows, terraces, outdoor cafes, industrial agricultural premises (farms for keeping livestock, poultry, boxes for keeping chickens) , individual workplaces, sidewalks, transport stops, etc. Gas radiant burners can heat individual areas (parts) of the premises in which people work. Heating with gas infrared burners is practically devoid of thermal inertia. Immediately after switching on, the heating system provides the necessary feeling of comfort. This heating can also be used intermittently, for several hours.
In terms of capital and operating costs, gas heating with infrared burners is more economical than convective. However, heating systems with gas infrared emitters require the removal of gas combustion products using supply and exhaust ventilation.
Rice. 9.21. Gas infrared heater of linear type.
Gas infrared heating systems create favorable microclimatic conditions in heated rooms due to a radiant flow of a certain intensity directed to the working area. The heating system includes a gas inlet, distribution and supply pipelines, a gas consumption metering unit, burners, locking devices, instrumentation and automation of remote ignition and safety. The system can operate both on natural network gas and on liquefied gas from a group tank installation. With gas supply from networks of medium or high pressure PIU and GRU should be provided.
Rice. 9.22. Gas infrared heating system. a - ventilation scheme of the room; b - heating unit from gas radiant burners; c - gas brooder; 1 - infrared burners; 2 - exhaust ducts with an axial fan; 3 - intake ventilation manifolds; 4 - exhaust shaft with gate; 5 – ceramic radiating nozzle; 6 – injection mixer; 7 - gas pipeline; 8 - frame; 9 - igniter; 10 - gas regulator; 11 - crane; 12–13 - pipes: 12 - to the burner, 13 - to the igniter; 14 - slag wool; 15 - suspension; 16 - radiating nozzle; 17 - heater; 18 - leg.The gas infrared heating systems used must be mass-produced, have a factory passport with a technical specification, which must indicate the duration of safe operation of the burner. The burners can be connected directly to the gas pipeline using metal pipes or rubber sleeves. The fastening of the sleeves to the burners and gas pipelines must be carried out with clamps. Burners should be installed on fireproof structures, shut-off devices - in front of each burner or a group of burners up to the rubber-fabric sleeve along the gas flow. The ignition of the burners can be carried out manually with a portable igniter or remotely (electric coil or spark gap).
Rice. 9.23. Mounting the infrared emitter.Gas infrared heating systems intended for rooms where there is no permanent attendant are equipped with automatic devices that ensure that the gas supply is cut off in the event of the burner flame going out. The heat output of the heating system can only be adjusted by changing the number of burners on.
Calculation infrared system heating is reduced to a comprehensive solution of the following issues:
- determination of the heat load of the heating system;
- determination of the number and type of emitters;
- choice of emitter layout;
- determination of the required air exchange and the choice of general exchange supply and exhaust ventilation.
The placement of infrared burners is determined by the allowable radiation density and uniformity of floor area exposure. Permissible intensity of infrared irradiation of a person Qdop at head level (without headgear) at a certain air temperature in the room is given in Table 9.36. Deviations in the intensity of irradiation up to 10% of the average value have practically no effect on a person, therefore, the unevenness of irradiation is allowed within 20–30% and is determined from the ratio
A \u003d 100 (1 - Q min / Q max)
Where Q min and Q max are the minimum and maximum intensity of infrared radiation, kJ / (h m 2).
To ensure a given intensity of irradiation of the floor and walls, it is necessary to place the burners in a certain order. At the same time, the dimensions of the radiating nozzle of the burners, the height of placement above the floor, and the distance between them are taken into account. In practical calculations, you can use the following relationship (if the burners are located horizontally):
L/H< 1 (9.1)
Where L is the distance between the centers (step) of the burners, m; H - distance from the floor to the burners (suspension height), m.
In this case, an estimate of the permissible irradiance can be made using averaged data for the entire heated room from the formula
ZQ ik /(η ik F p) = Q cf< Q д (9.2)
Where η ik is the radiant pyrometric coefficient (assumed to be 0.5–0.6); Q cf - the average intensity of infrared radiation, kJ / (h m 2); F p - heated area of \u200b\u200bthe floor and walls, m 2.
Rice. 9.24. Gas infrared emitter FAS-SPACERAY closed type for heating industrial premises.Due to the large heat transfer near the cooling surfaces and cold air currents, the edges of the floor near the outer walls along the perimeter of the building should receive 20–50% more heat than the rest. In addition, it should be borne in mind that the burners of the outer row are no longer affected by neighboring ones. Therefore, it is necessary either to reduce the distance between the burners, or to increase them. thermal power.
Infrared burners are placed evenly under the ceiling along the perimeter of the heated room with the burner radiating nozzle tilted to the outer fences or horizontally in such a way as to ensure the specified irradiance of the floor surface and outer walls at a height of up to 2 m. It is advisable to change the unit heat output of the burners used for heating depending on from the height of their installation.
Gas infrared radiators are manufactured at the Space-Ray (Great Britain) factory certified according to ISO 9002. The heat radiating tubes are made of a special aluminum alloy that provides a high heat transfer coefficient. Additional surface treatment of the tubes made it possible to achieve a monolithic structure that excludes heat losses. Emitters are available in U and Linear form factors and can be installed at heights from 2.1 to 15 meters. The warranty period for radiating tubes is 5 years.gas part The system was developed by FAS (Germany) taking into account the specifics of infrared heating technology and includes a full range of control and regulation equipment.
Prevent combustion products from entering the burner injector. The concentration of carbon monoxide in the products of gas combustion with the horizontal position of the burner with the emitter down due to the partial suction of these products by the injector increases by 2-8 times compared to the vertical position. It becomes less than the maximum permissible when the burner is tilted to the horizon by at least 20°.
Premises with heating using infrared burners are equipped with general exchange supply and exhaust ventilation that meets the requirements of the main production technology and the necessary air exchange to achieve acceptable concentrations of harmful substances from gas combustion products discharged into the room. When designing ventilation, it is necessary to carry out not only the calculation of technologically harmful substances, but also the verification calculation of the sufficiency of air exchange to remove water vapor and harmful substances formed during gas combustion.
In table. 9.37 gives the composition of the combustion products and the oxygen consumption for infrared burners. In industrial premises with gas infrared heating CO concentration should not exceed 6, in public - 2 mg/m3. To prevent the ingress of combustion products into the working area of the heated room, the ventilation system must ensure the removal of air from the upper zone above the level of the burners.
An approximate calculation of the heat load of the heating system and the determination of the number of burners can be performed according to the generalized averaged experimental values of the specific heat loads of the heated surface (floor), given in Table. 9.38. The data in the table can be used when designing temporary heating systems required when performing work in open or semi-open areas in winter time. Traditional heating systems (water, air) for such sites are practically unfeasible. The use of infrared burners for local heating allows creating favorable microclimate conditions. For these purposes, stationary and mobile installations (such as a tent, a thermal shower) with blocks of infrared radiation burners can be used. When operating in an open area, these units may have enclosing structures made of sheet materials to protect people from the wind.
In connection with high temperature radiating nozzles and their flammability of the system gas heating with infrared burners, according to fire safety requirements, it is not allowed to use in rooms:
- with productions A, B, C and E;
- storage of combustible and flammable materials and feed;
- livestock farms covered with straw and reeds;
- not provided with electric lighting;
- from light metal structures with combustible insulation in fences (walls and ceilings).
For industrial buildings of III–V degrees of fire resistance, the use of systems is coordinated with the technical and fire supervision authorities. It is not allowed to use these heating systems also in rooms with materials that, under the influence of infrared radiation, can change their properties and decompose with the formation of toxic or explosive substances.
Gas heating of railway equipment (turnouts). Automatic devices installed on the railway need careful and timely care and maintenance, since it is primarily about safety. This is especially true in winter, when modern turnouts, equipped with automatic devices and signaling, require very thorough cleaning of ice and snow, especially in the area where the point is attached to the frame rail.
Snow in the switch chutes accumulates continuously during snowfalls, snowstorms, as well as from trains moving along the arrows at high speeds. At certain conditions the intensity of skidding of the switch chute can be significant. The most dangerous are accumulations of snow on switch pads, in the area of thrust bolts, root fastening and sleeper boxes with transfer rods. Untimely cleaning of the gutters of the switch is accompanied, when it is translated, by pressing snow between the wit and the frame rail and prevents them from being pressed tightly.
Among the options for cleaning turnouts (pneumatic, requiring the construction of a special compressor station, and electric heating with a flow rate of 10–12 kW per switch), gas heating seems to be very promising.
The upper gas heating unit is a block of infrared radiation burners installed above the rails of the turnout on special columns. The burners are equipped with reflectors that provide a concentrated supply of infrared rays directly to the turnout and protect them from the wind. The heating system is equipped with an automatic system that ignites the burners when snow and ice appear and turns them off when the snow stops. Upper gas heating in mild climates provides sufficient cleaning of the turnout, but requires big expenses warmth.
The lower gas heating in any climate gives a high quality of cleaning of the turnout and requires 4-6 times less gas than the upper one. In this case, special gas burners with ceramic nozzles, torch burners and "dark" metal emitters are used as heaters.
Rice. 9.25. Infrared emitters provide a comfortable microclimatic environment.Considering that under operational conditions, the elements of the turnout are subjected to intense dynamic loads and operate in difficult meteorological conditions, the installation using "dark" emitters should be considered the most reliable. Gas heating installations with infrared burners equipped with perforated ceramic nozzles are also used. The emitters are installed on the outside of the frame rail (in the form of boxes) at a certain distance from each other. Remote ignition, shutdown and control are automatic. The disadvantage of this solution is the low resistance of ceramic nozzles to dynamic loads and insufficient heating of the wit in the pressed position under severe climatic conditions.
Gas heating installations can operate on both natural gas and liquefied propane. At large stations, near which there are gas pipelines, natural gas is used, at intermediate separate points, junction posts and single switches - liquefied gas. To store this gas, underground tanks or group gas-balloon installations are used. The gas supply is set taking into account the number of heated arrows and meteorological conditions. Usually it is taken from the calculation of the continuous operation of heating installations during the most protracted snowstorms and snowfalls observed in the area.
The quality of clearing the switch gutters from snow and ice depends on the heat output of the heaters and their arrangement on the switch. Determination of the thermal power of heaters is carried out on the basis of thermal calculation and experimental tests.
Table 9.36. Permissible intensity of infrared radiation depending on temperature
Table 9.37. The composition of combustion products and oxygen consumption during gas combustion in infrared burners (per 10 MJ of heat)
Indicators | Gas | |
natural | liquefied | |
Gas consumption, m 3 / hour | 0,286 | 0,110 |
The volume of wet combustion products, m 3 / hour | 3,05 | 2,86 |
Concentration in combustion products of carbon dioxide, volume/mass, m3/h/kg/h | 0,286/0,563 | 0,329/0,647 |
Concentration in the products of combustion of water vapor, volume / mass, m 3 / hour / kg / hour | 0,613/0,491 | 0,477/0,384 |
The volume of dry combustion products, m 3 / hour | 2,441 | 2,386 |
The volume of carbon monoxide in the combustion products at a concentration of 0.005%, volume / mass, m 3 / hour / mg / hour | 0,00012/152,7 | 0,00012/149,2 |
Oxygen consumption, volume / mass, m 3 / hour / kg / hour | 0,57/0,82 | 0,55/0,79 |
Table 9.38. Specific heat loads of the heated surface
heated object | Specific thermal load(intensity of infrared radiation), kJ / (h m 2) |
Enclosed rooms up to 5 m high when placing infrared burners at a height of up to 4 m | 460–565 |
Closed high rooms, industrial workshops without heat surpluses, Sport halls etc. when placing infrared burners at a height of 5 to 8 m | 750–960 |
Agricultural premises (farms for keeping young animals, birds, for milking, etc.) | 250–840 |
Enterprises Catering and other public spaces (halls, cafes, etc.) | 250–840 |
Partially open, wind-sheltered terraces, grandstands and assembly areas | 960–2100 |
Assembly and installation sites, sections of slipways and other industrial and construction facilities | Up to 4200 |
Table 9.39. Specifications gas infrared emitters FAS SPACERAY
Characteristic | "U" shape | "Linear" shape | |||||||||||
SRU 25 | SRU 30 | SRU 35 | SRU 40 | SRU 45 | SRL 09 | SRL 12 | SRL 15 | SRL 25 | SRL 30 | SRL 35 | SRL 40 | SRL 45 | |
Thermal power, kW | 23.0 | 29.20 | 34.50 | 42.20 | 47.0 | 9.0 | 11.40 | 15.0 | 23.0 | 29.20 | 34.50 | 42.20 | 47.0 |
Length, mm | 5385 | 5510 | 6970 | 5495 | 10065 | 9955 | 13000 | ||||||
Width, mm | 460 | 715 | 340 | ||||||||||
Height, mm | 175 | 210 | 180 | ||||||||||
Weight, kg | 47 | 66 | 81 | 27 | 46 | 62 | 79 | ||||||
Gas connector | 1/2 | ||||||||||||
Permissible pressure, mbar | Natural gas - 17–25; propane - 25–45; butane - 20–35 | ||||||||||||
Electrical connection | 230 V, 50 Hz, power consumption - 125 W | ||||||||||||
Diameter of the pipeline for the removal of combustion products, mm | 127 | ||||||||||||
Air connection pipeline diameter, mm | 101,6 |