Gas melting metal welding involves the use of equipment such as a gas torch. With its help, the metal surfaces to be joined are heated and melted. As a rule, all burners have a simple design, light weight, and are convenient to use. To choose the right tool for the work ahead of you, you should pay attention to the design features, as well as the types of burners.
How does a gas burner work? Operating principle
The design of a gas burner traditionally consists of an insulating sleeve, a nozzle, a diffuser, a mixing chamber, gas regulators, cable connectors, a handle equipped with a button, a cable, a connector and a tip mouthpiece. The gas burner device may include other elements - a piezoelectric element, a cooling system, and a feeding device. The presence or absence of certain components depends on the methods of supplying flammable gas.
- The injection type burner circuit includes an air supply regulator, a nozzle, a mixer, and a distribution manifold. Before final mixing, the gas-air mixture is rarefied, air is sucked in, then the stream is leveled in the diffuser and enters the collector, where it is evenly distributed among the holes.
welding torches: injection - a; non-injector - b; 1 - mouthpiece; 2 — tip tube; 3 - mixing chamber; 4 injector; 5, 6 - control valves; 7— trunk; 8 - tube; 9, 10—nipples
In turn, injection burners come in two varieties:
- with full injection or high pressure burners;
- with partial injection, or low pressure burners.
Devices of the first type are used mainly in heating boilers and for heating industrial furnaces. They ensure complete mixing of the components intended for combustion. The second type is common in furnaces for heating soldering irons, autosmokers, and in the furnaces of Strel and Strebel boilers. The combustion zone of such devices is provided with only part of the required air; a sufficient amount of it is drawn from the environment.
- Non-injection burners assume the same pressure for oxygen and fuel gas when they enter the mixer. Their design is complicated by a fan, an electric motor for drive, and air ducts. Due to these parts, non-injection burners can reach 1.9 m in length, which makes the tool not very comfortable to use.
Oxygen and combustion gas are delivered to the mixing nozzle in similar ways. From the cylinder, gases enter the burner through a tube, bypassing the control valve and the receiving nipple. In the mixing chamber, the gas flow rate decreases (as the cross section increases), and oxygen and combustible gas interact until a combustible mixture is formed that is homogeneous throughout the entire volume. Next, the mixture goes out through the nozzle onto the tube, where a welding flame is formed.
Knowing how a gas burner is structured and how it works, as well as how to correctly follow the sequence of parts, you can build such a device at home. However, it should be remembered that in order to ensure a constant rate of exit of the gas mixture from the mouthpiece, you need to carefully select the composition of the gases connected to each other, adjust the diameter of the outlet channel and pay attention to the design of the mouthpiece.
Welding torches operating on acetylene-oxygen combustible mixture
Oxy-acetylene welding uses the heat generated by the combustion of acetylene in oxygen. In terms of power, such burners are found in two common types: G2A and G3A (low and medium power burners). G2A torches are used when welding thin metal. The kit usually contains several tips of different sizes.
Particularly worth highlighting from this series are burners with a full complement of solid-drawn copper tips. The presence of solid-drawn copper tips in the G2A-mini torch kit allows you to carry out welding work in hard-to-reach places such as corner joints, where a conventional torch would be useless.
And the thickness of the copper tubes of the tips ensures a long operating time without overheating, due to good heat dissipation from the tip.
Purpose of the gas burner
A gas burner is used in those areas where stable combustion of fuel is required, the intensity and extent of which can be adjusted. Such a device can carry out:
- lighting. Open flame burners, argan oil burners, regenerative burners, and incandescent burners were popular before the invention of electricity and are rarely used today.
- heating. For example, when heating rooms, for laboratory experiments or for kitchen purposes.
welding torch Welding
torches are used in the industrial and construction fields. Depending on the type of welding, they supply a continuous stream of flammable gases to the weld site (in gas welding) or provide the arc combustion zone with shielding gas (in arc welding).
A portable gas burner for a cylinder will be useful for a tourist holiday. The sealed cylinder is reliably protected from fuel leakage, and the device with piezo ignition allows you to quickly light a fire without using matches or flint. A small can of gas will last more than one season of travel.
Note that a gas burner can be useful at home if:
- there was a need to unscrew a rusty nut;
- you need to decorate a metal or wooden surface in a vintage style;
- it is necessary to trim the ends of the nylon rope or geotextile;
- there is a need to repair the garden path using baked mass;
- you need to warm up the frozen lock;
- I want to cook meat outdoors, but I don’t have a grill. gas burner with piezo ignition
How to use a propane torch
A propane gas torch will be simply necessary when carrying out roofing work, drying casting molds, removing old paint, crimping couplings, soldering copper pipes, etc. Before using the burner, two cylinders are purchased - with oxygen and propane - on which reduction gears are mounted. The latter provide optimal pressure.
When the reducers are connected to the gas burner using hoses, you can unscrew the valves and release the gas. Before igniting, the gases pass through an injector where they are mixed. The temperature of the emerging flame exceeds 2 thousand degrees.
To carry out work, first open the valve with flammable gas, then with oxygen. The mixture coming out of the nozzle must be set on fire. The pressure of the consumables is adjusted based on instrument readings or flame color. Afterwards, using a filler wire, a weld pool is formed, and the molten metal must be moved, forming a seam. When the work is completed, the filler wire is removed and the gas mixture is extinguished.
Soldering technology
The area to be soldered must first be cleaned of dirt, rust, dirt and degreased. After preliminary preparation, the products are thoroughly dried and coated with flux. The parts to be soldered must be fixed so that the solderer has both hands free, since he will need to hold the torch and solder while working.
Then the product is heated so that the material is heated evenly along the entire length of the joint. To do this, the torch is continuously moved along the seam.
Pay attention to the burner flame. A properly adjusted flame has a dark core, middle part and edges with clear contours. If excess oxygen is supplied, the flame becomes sharply shorter, and if a lot of combustible gas is supplied, the middle zone disappears, the length of the flame increases, loses clarity, and the fire begins to smoke.
The highest temperature is at the end of the core, so preheating is best done with the outer part of the flame. After the soldering seam is heated to the melting temperature of the solder used, the end of a solder rod coated with flux is applied to the seam, which, when melted, closes the seam.
To avoid burnout, the solder must be heated quickly with a neutral, not very hot, flame. After soldering is completed, it is better not to touch the parts until the solder has completely hardened, so as not to displace the workpieces.
What gas can be used
Acetylene, hydrogen, and substitute gases (natural gas, propane-butane) can be used as combustible materials for a gas burner. Some designs operate on liquid flammable substances and waste oil.
gas burner cylinder marking
The combustible substance enters the acetylene burner from the generator apparatus, where calcium carbide decomposes into slaked lime and acetylene. The gas for the burner has a pressure of 100-150 mmHg. Nitrogen obtained from atmospheric air is used as a shielding gas, which prevents the formation of scale, and water is used as a catalyst for the decomposition of carbide.
The hydrogen torch is the most popular among similar equipment designed for gas-flame processing. It is important that when using it, only water vapor is released, so it is the safest. When an aqueous alkali solution decomposes, hydrogen burns, followed by the release of energy, which is needed to speed up welding. Hydrogen protects the weld from exposure to oxygen, thereby preventing oxidation of surfaces.
Many owners have an idea of how a liquid fuel gas burner works, since the operation of a kerosene stove is based on this principle. When heated in a special coil, the flammable liquid turns into gas and due to this, significant savings are achieved during subsequent combustion. As a rule, kerosene and Galosha gasoline are used as liquid fuel.
Knowing how to use a gas burner during mining, or a Babington burner, you can significantly save on consumables and reduce the cost of work. Such designs use motor, compressor, and any vegetable oil as fuel. The fuel enters a spherical part, from which it is blown off by a stream of compressed air. The resulting small droplets then ignite.
Indicators related to the flame of the device
gas burner flame
The burner flame power can be low (fuel consumption is 25-400 dm3/h), medium (400-2800 dm3/h) and high (2800-7000 dm3/h). Knowing the maximum and minimum power of a particular burner, you can calculate the fuel consumption and the amount of energy required to meet technological needs.
According to the number of flames, burners are single-flame and multi-flame. If the first type is used primarily for manual oxygen-acetylene welding, the second is widely used for mechanized flame soldering or heating.
Choosing the best option
When choosing a gas burner for various tasks, you should pay attention to certain nuances. For tourist purposes, the simplest torch burners without pressurization are well suited. Even cheap Chinese products can handle lighting a fire or heating food; you don’t mind breaking or losing them at all.
For household purposes and minor repairs, it is better not to purchase tools from the amateur series. Slightly more expensive semi-professional burners have a more thoughtful design and are devoid of such non-obvious shortcomings as, for example, melting of the plastic lining of the mouthpiece or malfunctioning piezo ignition. Another argument against the average price category is the almost universal absence of a normal control valve, which can be important even for rough work.
If the torch is selected for fine work, soldering or welding, additional attention should be paid to ergonomics and balancing. During such work, the burner has to be turned on and off frequently, so the shape of the body and the placement of the controls should allow ignition and precise adjustment with one hand.
When choosing power, you should be guided by the thickness and material of the parts being processed. A 500–700 W burner will be sufficient for burning paint or soldering copper wires. Tubes made of non-ferrous metals and steel products up to 3 mm thick will warm up well with a flame power of about 1200–1500 W. Burners of 2–3 kW are used for heating and bending reinforcement up to 14 mm thick. There is one more feature: the flame of powerful high-quality burners can be adjusted for more delicate work, but it will not be possible to heat a massive part with a low-power burner
Advantages and disadvantages of a gas torch for welding
The gas burner has the following positive qualities:
- a large number of types of devices;
- safety during operation;
- most models are compact and light weight;
- no lengthy preparation for use is required;
- does not leave soot or odor;
- the pressure of the fire can be adjusted;
- You can always find out what the device consists of and, if necessary, assemble a homemade burner.
Disadvantages of using a burner:
- at temperatures below -30°C, operation of the device becomes problematic;
- You cannot refill a flammable container yourself.
