The Concept and Purpose of Burner
A burner is a highly efficient combustion device that converts fuel into heat energy by combustion. In order to make the fuel or gas burn well and effectively utilize the heat energy, the fuel or gas must be fully mixed with the air, which is mainly achieved with the help of a burner.
The concept and purpose of burners
A burner is a highly efficient combustion device that converts fuel into heat energy by combustion. In order to make the fuel or gas burn well and effectively utilize the heat energy, the fuel or gas must be fully mixed with the air, which is mainly achieved with the help of a burner.
Burners are important equipment for oil and gas boilers. They are also widely used in industries such as metal heat treatment, melting, painting, drying, incineration, and lithium bromide refrigeration units.
Burner classification
(I) Burners are divided into oil burners, gas burners and oil and gas dual-purpose burners according to the fuel they use.
1. Oil burner:
1.1 The fuel used in oil burners is generally light diesel or heavy diesel. Light diesel is made from various straight-run diesel fractions, catalytic diesel fractions, and mixed thermal cracking diesel fractions. Its products are divided into three grades according to quality: superior products, first-class products, and qualified products. Each grade is divided into 6 grades according to the freezing point, namely 10, -10, -20, -35, and -50. Boilers generally use No. 0 or -10 diesel. Heavy oil is made by blending cracked heavy oil, vacuum heavy oil, atmospheric heavy oil, or wax oil in different proportions. It is divided into four grades of 20, 60, 100, and 200 according to the kinematic viscosity of 80 degrees.
1.2 Oil burners can be divided into primary, secondary, tertiary and proportional adjustment types according to the adjustment method. The primary burner has only one fuel nozzle and cannot change the load size; the secondary burner has two fuel nozzles, with different fire types; the tertiary burner has three fuel nozzles, with a total of three fire levels that can be changed; the proportional adjustment burner has only one proportional adjustment fuel nozzle, and the load size can be adjusted at will.
1.3 Oil burners can be divided into mechanical atomization type and medium atomization type according to their atomization form.
1.4 Composition of fuel burner: generally consists of burner casing, program controller, fan, oil pump, servo motor, electric eye, solenoid valve, combustion head, flame stabilizing disk, etc.
1.5 Functions of various components of the burner: The burner shell is the carrier of various components, and many components are fastened to the shell; the program controller is a device used to control the ignition program of the burner; the fan chamber drives the impeller to provide sufficient air for combustion; the oil pump is connected to the fan through a coupling, and the rotation of the fan drives the oil pump to provide fuel with a certain pressure for combustion; the servo motor is a device used to control the opening of the air damper to adjust the air intake to optimize the combustion conditions; the electric eye is a safety protection device on the burner. It can only transmit a current signal to the program controller when there is a flame, and the program can continue, otherwise it will fail to shut down; there is a pair of ignition electrodes and fuel injectors on the combustion head, and the high voltage ignition is output through the transformer to ignite the fuel; the flame stabilizing disk is a device used to adjust the ratio of DC wind and swirl wind.
1.6 Burner operation procedure: After starting up, the burner controller outputs a signal to start the fan running, and the servo motor drives the damper to the full load position for pre-purge. After the pre-purge, the servo motor drives the damper back to the ignition position. At this time, the ignition transformer outputs a high-voltage ignition electrode to ignite, and the solenoid valve opens at the same time. If the ignition is successful, the program will continue to convert the load size according to the heat demand. If the ignition is unsuccessful and the electric eye cannot detect the flame, the program will terminate, the solenoid valve will close, and no oil will be sprayed into the furnace.
2. Gas burner
2.1 The fuels used in gas burners are generally natural gas, liquefied gas and city gas.
Natural gas: Natural gas refers to gaseous fuel obtained directly from nature, that is, basically only gas that has been mined and collected. The main component of natural gas is methane.
Liquefied gas: Liquefied gas is a hydrocarbon obtained as a by-product during the extraction and refining of petroleum. The main components of liquefied gas are propane, propylene, butane and butene. When liquefied gas is converted from gas to liquid, its volume is reduced by 250 times.
City gas: City gas refers to the fuel gas produced by processing coal as raw material. Its main components are hydrogen, carbon monoxide, etc.
2.2 Gas burners can be divided into diffusion type, atmospheric type and flameless type according to the combustion mode.
Diffusion: The air required for combustion is not pre-mixed with the gas
Atmospheric: Part of the air required for combustion is pre-mixed with the gas
Flameless: All the air required for combustion is pre-mixed with the gas
2.3 Gas burners are divided into two types according to the adjustment method: two-stage and proportional adjustment. Two-stage burners only have high fire and low fire; proportional adjustment burners can work at any load point.
2.4 Composition of gas burner: generally consists of burner casing, program controller, fan, servo motor, gas butterfly valve, combustion head, ionization electrode or ultraviolet electric eye, flame stabilizing disk, gas valve group (including ball valve, expansion joint, filter, pressure regulating valve, solenoid valve, ignition solenoid valve, etc.).
2.5 Functions of various parts of the burner: The burner shell is the carrier of various parts, and many parts are fastened to the shell; the program controller is a device used to control the ignition program of the burner; the fan chamber drives the impeller to provide sufficient air for combustion; the servo motor is used to control the opening of the air damper and the opening of the gas butterfly valve, that is, to control the ratio of air volume and gas volume to achieve the effect of complete combustion; the ionization electrode and ultraviolet electric eye have the same function as the electric eye on the oil burner, which is used to detect the presence of flame. If the flame does not exist, the protection will be shut down; there is a pair of ignition electrodes and gas nozzles on the combustion head. Nozzle, the transformer outputs high voltage ignition to ignite the gas ejected from the nozzle; the flame stabilizing disk is a device used to adjust the ratio of DC wind and swirl wind; the ball valve in the gas valve group is a cut-off device, used to supply gas and cut off the gas when not in use; the expansion joint is used to reduce the stress generated during the installation of the gas valve group; the filter is used to filter impurities in the gas to prevent impurities from damaging the equipment; the regulating valve can be used to adjust the gas pressure coming out of the gas pressure regulating box so that its pressure is suitable for the gas consumption of the burner; the ignition solenoid valve is used to release the ignition gas to ignite a small fire first; the solenoid valve is opened after the ignition gas is ignited to release the main gas to ignite the main flame.
2.6 Burner operation procedure: After starting up, the burner controller outputs a signal to start the fan running, and the servo motor drives the damper to the full load position for pre-purge. After the pre-purge, the servo motor drives the damper back to the ignition position. At this time, the ignition transformer outputs a high-voltage ignition electrode to ignite, and the ignition solenoid valve opens the branch gas at the same time. If the ignition is successful, the main solenoid valve opens and the flame is ignited. Then the program will continue to convert the load size according to the heat demand. If the ignition is unsuccessful, the ionization electrode or the electric eye cannot detect the flame, the program will terminate, the solenoid valve will close, and no gas will be released into the furnace.
3. Oil and gas dual-purpose burner:
3.1 The classification of oil and gas dual-purpose burners is the same as above, and the components of oil and gas burners are integrated into one body, which can switch between oil and gas fuels at will.
(ii) Burners can be divided into two categories according to their structural form: integral type and split type.
1. The integrated burner is a burner body, burner fan and combustion system (including pump, solenoid valve, servo motor, etc.) integrated into one.
2. Split burner means the burner body (including combustion head, fuel oil or gas system), burner fan and burner control system (including control box, fan thermal relay, AC contactor, etc.) are three independent systems.
3. Selection of burner
The selection of oil and gas boiler burners should be based on the structural characteristics and performance requirements of the boiler body and combined with the user's usage conditions to make a correct comparison.
Generally, you can choose according to the following principles:
1. Select according to the type of fuel used by the user. Fuel types include liquid fuel oil, kerosene, diesel, heavy oil, residual oil and waste oil; gas fuel oil, city gas, natural gas, liquefied petroleum gas, and biogas. The fuel used should have necessary analysis data:
Kerosene and diesel should have calorific value and density; heavy oil, residual oil and waste oil should have viscosity, calorific value, moisture, flash point, mechanical impurities, ash content, freezing point and density; fuel gas should have calorific value, gas supply pressure and density.
2. Select the nozzle atomization method or gas combustion type in the oil burner according to the boiler performance and furnace structure.
3. The output power of the burner should match the rated output of the boiler, and the shape of the flame, such as length and diameter, should be selected to adapt to the furnace structure. The air required for fuel combustion should be supplied from the root of the flame to evenly mix the oil mist or gas with the air to ensure complete combustion.
4. The burner adjustment range should be large to adapt to the needs of changes in boiler load and ensure completely stable combustion under different operating conditions.
5. The energy consumed in fuel atomization and digestion should be less, and the resistance of the air regulating device should be small.
6. The impact of flue gas emissions and noise must comply with environmental protection standards, mainly SO2 , CO and NOx emissions must be lower than international regulations, and low NOx and low noise burners should be selected.
7. The choice of integral or split burner should be based on the specific conditions of the boiler and user requirements.
8. Burners with simple structure, reliable operation, easy adjustment, control and repair, and easy to realize automatic control of the combustion process should be selected.
9. A comprehensive comparison should be made of the burner brand, performance, price, service life and after-sales service.
10. In addition to overcoming the resistance of the boiler body, the wind pressure of the burner should also take into account the resistance of the flue gas system.
4. Safety rules for burners
Oil Burner Safety Rules
1. Room where the burner is located
There must be dedicated ventilation holes, and the ventilation holes must be set up in accordance with local requirements. The room should be kept clean.
2. Fuel
The burner fuel must comply with the requirements in the technical parameters.
The oil pressure before entering the burner pump must meet the technical parameter standards.
The oil pipes in and out of the burner must be completely sealed, and foreign objects should be prevented from entering the oil pipeline during installation.
Foreign matter or water should be prevented from entering the oil pipe, and the oil tank should be filled with oil in summer to avoid condensation.
Clean the fuel tank before filling it with oil.
3. Electrical input
Confirm the electrical power according to the operating manual. The burner must be grounded.
Never confuse the neutral wire with the live wire, and never touch the burner with wet hands.
Do not pull the wires too tight and keep them away from high temperature sources.
4. Burner installation and setting
The burner must be securely placed against the boiler. Before ignition, obtain the consent of the boiler room supervisor, confirm whether the boiler is full of water or heat transfer oil, and whether the water circulation valve is open, and then do the following:
Set the fuel quantity according to the required output of the boiler and the output range of the burner stated in the manual.
Adjust the burner air door position and combustion head position.
Confirm the boiler furnace pressure provided by the boiler manufacturer.
Ensure flue gas emissions are below local standards depending on the fuel type.
Check whether the safety mechanism and regulating mechanism are effective.
Before leaving, make sure all mechanisms are in place.
5. Maintenance
The burner must be overhauled at least twice a year.
Before performing maintenance, disconnect the power supply and close the fuel valve.
5. Burner Instructions
This burner is fully automatic and does not require manual command set monitoring. To avoid malfunctions, please pay attention to the following:
1. Be familiar with safety rules.
2. To achieve maximum reliability and best economy, the burner must be maintained regularly, at least twice a year.
3. Pay attention to any unusual sounds.
4. If the burner cannot start normally and the fire indicator on the control box is not on, check whether the power reaches the burner, whether the fuse is normal, and whether the burner control system is connected. On the other hand, if the burner stops working and the fire indicator on the control box is on, press the reset button to let the burner try to ignite automatically. If it cannot be ignited and the fire indicator is on again, please check whether there is oil in the mailbox and whether the manual valve of the combustion pipeline is open. If the burner still cannot start after the above conditions are confirmed, please contact a technician.
5. If the power supply is missing a phase, the thermal relay in the burner will be activated, the burner will enter a locked state, and the fire light will be on. After connecting the missing phase line, please press the thermal relay reset button to start again.
6. When the fuel is used up, the burner will automatically shut down and the fire light will come on. Before restarting, please increase the oil level to prevent air from mixing into the oil circuit.
7. When the ambient temperature is below -10℃, if the fuel tank is placed outdoors, please protect the fuel tank and fuel pipes to prevent the wax in the oil from solidifying and causing the burner to lock.
8. Make sure there is no dust in the burner room.
9. If the burner is not used for a long time, please cut off the main power supply and close the oil valve.
10. Common faults and troubleshooting methods
|
Fault |
Causes |
Suggested solution |
|
Burner does not start |
No power |
Turn on all switches - check fuses |
|
Limit or safety control device open |
Adjust or replace |
|
|
Control box lock |
Press the reset button on the control box |
|
|
Motor lock |
Press the thermal relay reset button |
|
|
Pump failure |
replace |
|
|
Controller fuse is broken |
replace |
|
|
Circuit connection error |
Check the circuit connection |
|
|
Control box damaged |
replace |
|
|
Motor control unit damaged |
replace |
|
|
Motor damage |
replace |
|
|
Capacitor damage |
replace |
|
|
Photoelectric tube short circuit |
replace |
|
|
Light leaks or simulated flames appear |
Clear the light leak or replace the controller |
|
|
Stop the burner immediately after starting |
Phase loss (except GW) |
Press the thermal relay reset button |
|
The burner is locked immediately after the air is blown and the flame does not appear |
There is no oil in the mailbox, or there is water at the bottom of the tank |
Refuel or drain |
|
The combustion head position or door air position is not suitable |
Make adjustments |
|
|
Solenoid valve cannot open |
Check the wiring and replace the coil |
|
|
Nozzle clogged, dirty work damaged |
Clear or replace |
|
|
Ignition electrode position is incorrect |
Adjust and clear |
|
|
Poor insulation of ground wire |
replace |
|
|
High voltage cable damage |
replace |
|
|
Ignition transformer damaged |
replace |
|
|
Solenoid valve or ignition transformer wiring error |
replace |
|
|
Control box damaged |
replace |
|
|
Pump does not start |
replace |
|
|
Damaged coupling between pump and motor |
replace |
|
|
The oil inlet and return pipes are connected incorrectly |
correct |
|
|
Dirty pump, filter or nozzle screen |
Cleaning |
|
|
Motor direction error |
Phase Commutation |
|
|
Burner lockout after flame appears |
Ignition electrode is incorrect |
Adjustment |
|
Photoelectric tube or controller is damaged |
replace |
|
|
Photocell dirty |
Cleaning |
|
|
Unstable flame |
The combustion head position is set incorrectly |
Adjustment |
|
Ignition electrode position is incorrect |
Adjustment |
|
|
The air door is too large |
Adjustment |
|
|
The nozzle is not suitable for this burner or boiler |
Check and adjust |
|
|
The nozzle is broken |
replace |
|
|
Inappropriate pump pressure |
Adjustment |