Combined burners are used in areas where interruptions in gas supply may occur, and the ability to urgently switch to another type of fuel is required. Also, these elements are in demand where the main fuel is supplied to the object according to a certain schedule, and also if the necessary thermal regime of the furnace is not provided. Consider the characteristics and features of these devices.
Oil-gas modifications with forced air supply
Combined burners of this type consist of three parts:
- Gas compartment (hollow ring with inlet fitting and eight tubes for spraying the working mixture).
- The liquid block is a fuel oil head and an internal element with a nozzle. The fuel oil supply volume is adjusted using an adjustable screw.
- Air part. The unit includes a housing, a swirl (needed for better mixing of the working mixture), a damper for adjusting the air supply.
The operation of combined gas burners allows to increase the effect of the functioning of the units than the use of fuel oil and gas nozzles separately. The design in question is optimally suited to ensure uninterrupted and reliable operation of the corresponding installations at large industrial enterprises, power plants and other consumers requiring continuous operation.
Dust-and-gas variant with central gas supply
Combined coal dust burners operate according to the following principle: an air mixture with the specified type of fuel enters through the circular motion of the main pipe, and the secondary part of the dust-air mixture flows through the cochlea into the furnace.
Fuel oil serves as a backup fuel, for which a special nozzle is provided in the central channel. When the gas mode is activated, the indicated element is replaced by a ring analog. In its central part, a tube with a cast-iron tip is mounted. It is equipped with slanting slots, which are used to release gas, which is connected to the air at the outlet of the cochlea. In advanced versions, instead of 24 outlet windows, holes with a diameter of seven millimeters, in the amount of 115 pieces, are provided. This allows you to increase gas output by 50 percent. These models use a peripheral fuel supply, which guarantees high-quality mixing of all components of the mixture with minimal losses.
Block version
These combined burners are designed for operation in the working chambers of various thermal devices, including heat and water boilers, special furnaces and similar installations.
At the input of the housing there is a intake with a damper and an actuator. The last part consists of an electromagnet and a block of levers, aggregating with a locking axis. A motor is attached to the skeleton, with a centrifugal fan on the shaft. A mixer with a swirl and electrodes is provided on the flange of the housing; a neck is fixed at its end.
Scheme BG-G (side view)
Below is a schematic illustration of a DG-G type fuel burner with explanations.
- Wreck.
- Viewing window.
- Pulse type generator.
- Air pressure switch indicator.
- Quick release finger.
- High voltage cable.
- Nozzles for gas supply.
- Adapter with nozzle.
- Swirler.
- Seal in the form of a ring.
- Gasket.
- Gas distribution unit.
- Axis.
- Air intake.
- Damper
- Bracket.
- Electromagnet.
The principle of action of BG-G
The mixer on the specified design reclines in two positions. This facilitates access to the high voltage wires and gas nozzle. This element is connected to the appropriate wiring and fittings. Attachment points at all joints are sealed with special rings and gaskets.
For controlling the intensity of operation of the combined burners for boilers, the remote control is fixed on the housing with the bracket. The air in the working chamber is supplied using an electric fan, the volume of the mixture is adjusted by means of an air damper.
At rated thermal power indicators, the electromagnet is in an inactive state (de-energized), and the damper is open in the “zero” position on the limb of the air intake. The "small fire" mode provides power to the magnet, after which it is triggered, causing the flapper to rotate on the axis to position No. 3.
Gas is supplied through the wiring to the nozzle, through the nests of which it enters the air stream swirling in the swirl. The volume of fuel supplied to the combustion chamber is regulated by electromagnetic valves. As a result, the mixture is ignited by a spark, which is formed between the nozzle and the ignition electrode from the supply of high voltage current.
Other block burner elements
Below is a diagram and a breakdown of the positions of the other nodes of the BG-G system.
- 18 - control panel.
- 19 - The electromagnetic valve.
- 20 - sensor.
- 21 - valve fittings.
- 22 - pressure switch indicator.
- 23 - crane.
- 24 - electric fan.
- 25 - engine.
- 26 - relay.
- 27/28 - zero and ignition electrode.
Operating modes
Block mechanisms have several operating ranges. Among them:
- Purge. In this mode, turn on the fan, which supplies the required amount of air to the combustion chamber. In this case, the actuator will be in a de-energized state, and the damper will be fully open. At the wiring, the solenoid valves are also inactive, preventing the excessive supply of gas to the burner.
- Ignition. After purging, use this mode. For this, power is supplied to the actuator, after which it rotates the axis of the damper, reducing the flow of the air mixture. A valve or electromagnetic valves are switched on simultaneously, gas is supplied to the burner, and a pulse generator transforms a high voltage to the ignition electrode. A spark arises in the working chamber, providing ignition of the gas-air composition.
- "Small fire" is also referred to as the ignition mode.
- Operational features. At this stage, the operation of all major nodes is monitored. If normal ignition with a steady flame is observed at the ignition stage, the electromagnetic valve is activated by disconnecting the magnet. As a result of this, the maximum possible opening of the air damper is formed. After that, the burner operates in the "big fire" mode. Heat power is adjusted by means of special regulators.
Combined burners Elco
This manufacturer specializes in producing analogues that use gas or diesel fuel. Details are focused on boiler installations with a power not exceeding 2050 kW. By the type of adjustment, the elements are divided into several modifications:
- Two-fuel single-stage options.
- Models with smooth pair type of adjustment.
- Standard two-stage versions.
- Equipment with pneumatic control.
- Three-stage analogues.
Combined gas / diesel burners are operated in facilities requiring a continuously guaranteed supply of heat continuously. The main type of fuel is gas, but at any time the equipment can be transferred to aggregation with diesel fuel. Such nozzles are widely used in thermal industrial generators, heating, water heating and drying industries.
Modifications
The Elco assortment includes several varieties of the parts in question:
- Model "Vectron" VGL-2. It operates in a pressure mode from 30 to 190 kW, has a single-stage design.
- VGL-3. Power - 95-360 kW. Work step - two modes.
- Burner combined "gas / diesel" for 500 kW modification VGL-4. The maximum and minimum threshold is 460-610 kW.
- Versions VGL-5 and 6 have a smooth dual-mode design, designed for power from 700 to 2050 kW.
Exploitation
Designs "Elko" are operated in the agricultural, baking sector, light, heavy chemical industry. It is worth noting that the market offers combined gas / diesel burners with a monoblock in which the fan is mounted in the fixture body, or in twin versions with a separate boost.
The following items are included in the package:
- The burner itself.
- Mixing mechanism.
- Ramp with gas multiblock.
- Built-in filter.
- Pressure switch.
- Solenoid valves
- Pump.
- Fan.
If necessary, the products can be supplemented with special pumps for supplying liquid fuel and related accessories. These include stopcocks, valves, couplings, indicators, fixing flanges and other specific equipment.
In conclusion
Combined burners with a monoblock device are placed in a single design. On the market are household analogues, versions for medium-sized enterprises and industrial modifications. Between themselves, they differ in the type of fuel used, the features of ignition and size. The main advantage of this equipment is the ability to switch from gas to another type of fuel, ensuring the smooth operation of important and strategic facilities. On two-stage versions, the system is somewhat more complicated. They are more effective in terms of maximum fuel combustion, have an increased efficiency, provide a smooth transition between operating modes, are operated in various food, industrial and agricultural sectors.