Gas burner on a spray can: selection and use. Blow Torch Flame Temperature Performance Gas Torch Applications

For soft roof optimal hydro and thermal insulation materials are those that are welded with a roofing burner. This is labor-intensive and complex work, which, moreover, is performed at height. result quality installation The roof will last a long time. Therefore, only high-quality equipment is selected for work. In the article we will consider existing species and advantages of various roofing burners.

What is a roof burner

This is a special equipment for heating the built-up roof. In addition, with the help of a burner, the surface is dried, workpieces are heated for construction work, building paint is fired and used in all work where it is required to heat elements or surfaces.

The gas burner for the roof consists of:

a metal cup made of heat-resistant material;
gas supply hose;
nozzles for ignition of a torch with protection against wind.

The roof burner is a mobile design with comfortable handles for carrying it. It has a small weight, up to 1.5 kg, and is equipped with a convenient handle made of wood or plastic up to 1 m long.

Propane is the most commonly used gas. It enters the body through a gas pipeline. Regulate its supply and the length of the flame using a special valve on the burner. To save gas consumption, roof burners are equipped with a gearbox that controls the fuel consumption.

In all designs of gas burners, an atmospheric air suction system is provided. This is a mandatory feature, but there are additional ones that make the work more comfortable. First of all, the ability to regulate operating modes. For example, when work is interrupted, standby mode is activated and fuel is saved. Any gas burner is ignited with regular matches or a lighter.

Less popular, but also used for roofing, are diesel-fuelled burners.

Application of gas burners

They are used in most branches of construction and industry.

The design of gas burners depends on the fuel on which they operate and on the area of application. But in general they are identical. The burner, consisting of a body, a lever for adjusting the flame of a valve for supplying fuel, is connected to a gas cylinder through a reducer. Some manufacturers supplement the designs of gas burners with additional flame wind protection and piezo ignition.

Types of gas burners

For laying roofs made of bituminous materials, hand burners are used. Most often, these are propane burners for the roof of a lever structure. They are easy to use - the length of the flame is easily adjusted by simply pressing the lever mechanism, switching to an economical mode of gas consumption.

During operation, the gas burner consumes a mixture of propane with air or with the addition of technical oxygen. Gas-air burners are the safest for operation. They provide sufficient temperature for roofing, heating metal parts, annealing paint and soldering cables.

Valve-type gas burners are easy to use, light in weight and do not cause difficulties in repair. By creating a high flame with high power, they make it possible to work even in windy weather.

There are also acetylene torches that run on a mixture of acetylene and oxygen. Most often they are used for welding. They are designed in such a way that oxygen, in injection acetylene burners, is needed not only to maintain combustion, but also to supply acetylene.

In addition, burners differ in functionality and have different abbreviations:

GV 500

Are applied at roofing works. It is capable of creating a heating temperature of up to three hundred degrees, which is quite enough for fusing all bituminous materials;

GV 850

More advanced model. It has a valve for fine adjustment of the technical gas supply from the cylinder. And thanks to the lever, the length of the flame is easily adjusted during work. Its power is enough to melt metal-plastic pipes and refractory cables.

GV 3

Runs on propane. It is used for heating and welding of metal and hand soldering. The size of the glass diameter is 5 cm.

GGS1-1.7

The most versatile and most popular burner. Heats the surface up to four hundred degrees. It is used when laying soft roofing materials, road and waterproofing works. Power is 115 kW with fuel consumption of 9kg/h.

GGS1-1.0

It is irreplaceable for work in limited space and on a roof with a big angle of inclination. It is a good replacement for a conventional blowtorch. With small dimensions (length 50cm) it has great power, is safe, economical and convenient to use. Its power is 40 kW, and the gas consumption is 3 kg/h.

GGS1-0.5

It is used for small roofing repair, soldering, welding of cables. Due to economical fuel consumption, it can work with a five-liter gas bottle. The power is 10 kW, the consumption is 0.7 kg/h.

GGS2-1.5

Equipped with two parallel sockets, thanks to which it has a high performance. Power 179 kW with fuel consumption 14kg/h.

GGS4-1.0

Or a spreader. It has 4 sockets, which provides simultaneous heating with a width of 1 meter and allows you to work non-stop. There are special hooks for the roofing material along the cuts; with their help, one person can perform all the work on laying it. Power 120 kW, consumption - 12 kg/h.

Gas burners are used in all types of construction and repair work and can heat surfaces up to four hundred degrees. In particular: gas-air injection burner GG-2, gas burner GVK 1, liquid fuel burner GRG-1, propane burner GSP-3, propane burner GVK-1-R, propane burner GSP-4 and others.

The price of gas burners for roofing varies greatly and depends on many factors: performance, additional functions, the ability to work with a particular fuel, as well as the manufacturer. It is worth noting that they are inexpensive and available to most consumers.

What you need to know when working with a gas burner for a soft roof?

Consider this on the example of roofing work when laying roofing material:

first, the entire surface is cleaned - not only large debris is removed, but also fine dust;
for marking, sheets of roofing material are laid out on the roof with an overlap of up to 10 cm, after which it is twisted, and the edges of all sheets are fixed with a gas burner at the base of the roof;

during operation, a roll of roofing material is rolled out gradually, melting and pressing tightly to the roof surface. All wrinkles and bubbles under the material should be removed immediately. When working on flat roofs this is done using a hand roller;
the final stage of work with a gas burner will be the heating of all seams of the roofing material. When heated, it melts, sticking tightly to the bottom sheet. Additionally, the seams are reinforced with a hand roller.

When a high-quality gas burner with adjustable fuel supply is used for work, up to 600 m of roofing material can be laid non-stop.

Important! It is allowed to use a gas burner for a soft roof at a temperature not lower than 15 degrees. If work is required at a lower temperature, an oil burner will be required.

Safety precautions when working with a roofing gas burner

Roofing work is required in special clothing and shoes with non-slip soles;
use the safety system;
Before use, the gas burner is carefully inspected. It is necessary to make sure that all structural elements are in good condition;
during the operation of the burner, there must not be a second gas cylinder on the roof. Also periodically it is necessary to check the tightness of the hose connection with the reducer and the cylinder;
when igniting the burner, in no case should you be in front of the nozzle;
adjust the height of the flame so that it does not touch the cylinder, hose or people;
when heating the welded roofing material, it must not be allowed to ignite;
only the lower part of the sheet should be melted, without softening the entire thickness of the material;
when igniting a propane burner, first open the valve half a turn and leave it to purge for a few seconds. And only then can the mixture be ignited and the height of the flame can be adjusted;
with a working gas burner, it is forbidden to leave working area or climb the scaffolding;
to extinguish the burner, the gas supply is first blocked, and then the lock lever is lowered;
if the burner overheats or a backlash occurs, work is immediately stopped, the gas is shut off, and the burner is placed in a container of cold water to cool.

Buy a ready-made burner or make your own?

It should be said right away that it will be much easier and safer to buy a ready-made burner than to make it yourself. But if you have confidence in your abilities and love to do everything with your own hands, then you can try.

A gas burner is a complex device and in order to make it you will need certain skills and thorough adherence to many rules. But still, part of the work is best left to professionals. First of all, this concerns the supply system and gas storage tanks.

For the manufacture of a torch, a metal rod and a divider are used. They are attached to the handle made of heat-resistant wood.

The gas supply hose is borrowed from the gas welding system or independently machined from brass.

Despite the fact that outwardly a do-it-yourself roofing burner will differ significantly from store counterparts, it will cope with its main functions.

But when working with it, you will have to pay special attention to the slightest gas leaks or other malfunctions. And even with a minor problem, work should be stopped immediately.

Roof diesel burner

These roofing burners operate on liquid fuel. They are especially relevant for operation at a large temperature minus, in which case they are equipped with built-in fuel heating. They are fully automated and are able to work with fuel of various qualities. The diesel roof burners are equipped with a high-pressure blower system that ensures stable and safe ignition and reduces soot formation.

Liquid fuel burners are structurally different from gas counterparts. In diesel fuel, the fuel enters the chamber under high pressure, which causes the liquid to be atomized. And the smallest particles already sprayed are ignited at the outlet of the nozzle, creating a flame. In this connection, the burner is connected to the compressor and the fuel tank using oil and petrol resistant hoses.

The oil fired roof burner is designed to operate under the following conditions:

at ambient temperature from - 25 to + 40 degrees;
at atmospheric pressure - 101 kPa;
if necessary, flame temperatures up to 600-800 degrees.

In this case, the approximate consumption of diesel fuel is 10 l / 100 m2 of area.

How to work with a diesel roof burner:

check the serviceability of all structural elements;
turn on the compressor to supply air to the nozzle. Then, having opened the fuel supply valve, bring a special igniting tourniquet to the nozzle. After igniting the diesel fuel supply tap, adjust the flame level.

The current generation of “lefties” rarely uses a blowtorch, preferring to it an electric industrial hair dryer or a gas burner, which are much easier and safer to use. But even 40-50 years ago, a blowtorch was in almost every home workshop of a locksmith or car enthusiast, since it was the only tool capable of heating various materials to the desired temperature.

A blowtorch burns gasoline in a nozzle, giving out a fairly large jet of open flame.

But to hand over a blowtorch for scrap in our age of scientific and technological progress is still not worth it. For example, a gas burner severe frost almost impossible to ignite. With an industrial hair dryer, the situation is no better: it needs permanent source electricity. And an old blowtorch does not care about all these difficulties.

Read also:

- step-by-step instruction.

What is a jigsaw and how to use it -
The principle of combustion in a blowtorch

A blowtorch is a heating device that runs on liquid fuel. Its peculiarity is that in the working tool, the burner, the vapors of the fuel filled into the lamp burn, and not the fuel itself. Entering the burner at high speed, the jet of such vapors sucks in the air around the burner, thereby providing itself with a sufficient amount of oxygen.
Such self-sufficiency is very important, since a certain amount of oxygen is needed for the complete combustion of 1 kg of hydrocarbon-based liquid fuel. In this case, complete combustion will be achieved, after which only carbon dioxide and water will remain from the fuel.

But if you simply ignite a liquid fuel, such as gasoline, in an open container, it will not burn completely. This is indicated by the orange-red flame of such burning hearths, moreover, with a fair amount of soot. But if air is artificially pumped into such a combustion center, then the flame from orange-red will turn blue, practically without soot, and its temperature will increase significantly. The reason for these changes will be the oxygen in the air.

It is the principle of artificial enrichment of the flame with air, borrowed from gas lamps (the so-called horns), that is the basis for the operation of a blowtorch. Moreover, such an air supply is regulated spontaneously: fuel vapors enter the burner, and the larger the flow, the more powerful the jet will be and, accordingly, the more air it will draw into itself.

Sometimes it happens that the jet draws in too much air, and the oxygen does not have time to completely burn out. In this case, the combustion temperature is noticeably reduced, since the excess air, passing through the burner, cools it. However, this only happens when low-quality fuel is used. When the burner is normally filled with fuel vapor, it is impossible to draw an excess amount of air into it for purely physical reasons.

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Blow Torch Fuel

The versatility of a blowtorch is that it can work on almost any flammable liquid fuel: alcohol, kerosene, gasoline, diesel fuel, oil. But this does not mean at all that anything can be poured into every blowtorch.

Fuel must be of high quality. In addition, it must be borne in mind that an unsuitable type of fuel will very quickly clog the nozzle with its fumes. Today, blowtorches come in three types:

kerosene;

gasoline;

alcohol.

The principle of a blowtorch is also preserved in the operation of a gas burner, so some specialized sources also refer to this device as blowtorches, highlighting it as a separate, fourth, type.

Filling the lamp with another type of fuel that does not correspond to its design is strictly prohibited by the safety instructions. And this rule must be strictly observed. After all, kerosene poured into a gasoline “soldering iron” will turn it into a tool like a flamethrower. Getting into the burner, it will not have time to completely evaporate, therefore, it will not be the vapors that will burn, but the kerosene itself. Such a tool will not work normally.

It is even more dangerous to pour gasoline into a kerosene blowtorch. Gasoline evaporates much faster than kerosene, and its vapor pressure in the burner will be 6 times higher than the calculated one. If you try to ignite the fumes will explode, turning a useful tool into a dangerous bomb. Therefore, if you use a kerosene blowtorch, you need to fill it only with pure kerosene, without any impurities, without using mixtures of kerosene with gasoline or other fuel.

The same situation is with a gasoline blowtorch. It should only be filled with clean gasoline. At the same time, the indicator of the octane number of gasoline has practically no effect on the operation of the tool: neither on the ignition rate, nor on the burning time, nor on the flame temperature. But when choosing a brand of gasoline, one should not forget that low-octane brands have much less various additives and impurities, so the nozzle will become much less dirty during operation.

Alcohol blowtorches have a small tank volume (only 200-300 ml), respectively, its burning is very limited in time, so today craftsmen prefer to use gas burners instead.

The temperature of the fire makes you see familiar things in a new light - a white match that flared up, the blue glow of a gas stove burner in the kitchen, orange-red tongues above a flaming tree. A person does not pay attention to the fire until he burns his fingertips. Or not burn the potatoes in the pan. Or it won’t burn through the soles of sneakers drying over a fire.

When the first pain, fear and disappointment pass, it is time for philosophical reflection. About nature, colors, temperature of fire.

Burns like a match

Briefly about the structure of a match. It consists of a stick and a head. The sticks are made of wood, cardboard and cotton cord impregnated with paraffin. The tree is chosen soft breeds - poplar, pine, aspen. Raw materials for sticks are called matchsticks. To avoid smoldering straws, the sticks are impregnated with phosphoric acid. Russian factories make straws from aspen.

The head of a match is simple in shape, but complex in chemical composition. The dark brown head of a match contains seven components: oxidizing agents - Berthollet salt and potassium dichromate; glass dust, red lead, sulfur, zinc white.

The head of a match ignites during friction, heating up to one and a half thousand degrees. Ignition threshold, in degrees Celsius:

poplar - 468;
aspen - 612;
pine - 624.

The temperature of the fire of a match is Therefore, the white flash of the sulfuric head is replaced by a yellow-orange tongue of the match.

If you look closely at a burning match, then three zones of flame appear to your eyes. The bottom one is cold blue. The average is one and a half times warmer. The top is the hot zone.

fiery artist

At the word “bonfire”, nostalgic memories flash no less vividly: the smoke of a fire, creating a trusting atmosphere; red and yellow lights flying towards an ultramarine sky; overflows of reeds from blue to ruby-red; crimson cooling coals in which "pioneer" potatoes are baked.

The changing color of the flaming wood indicates fluctuations in the temperature of the fire in the fire. Wood smoldering (darkening) starts at 150°. Ignition (smoke) occurs in the range of 250-300°. With the same supply of oxygen to the rocks at different temperatures. Accordingly, the degree of the fire will also be different. Birch burns at 800 degrees, alder at 522 degrees, and ash and beech at 1040 degrees.

But the color of the fire is also determined by the chemical composition of the burning substance. Yellow and orange contribute sodium salts. Chemical composition cellulose contains both sodium and potassium salts, which give the burning coals of wood a red tint. Romantic in a wood fire arise due to a lack of oxygen, when instead of CO 2 CO is formed - carbon monoxide.

Enthusiasts of scientific experiments measure the temperature of a fire in a fire with a device called a pyrometer. Three types of pyrometers are produced: optical, radiation, spectral. These are non-contact devices that allow you to evaluate the power of thermal radiation.

Exploring fire in your own kitchen

Kitchen gas stoves work on two types of fuel:

The main natural gas is methane.
Propane-butane liquefied mixture from cylinders and gas holders.

The chemical composition of the fuel determines the temperature of the fire gas stove. Methane, burning, forms a fire with a power of 900 degrees at the top.

Combustion of a liquefied mixture gives heat up to 1950 °.

An attentive observer will note the uneven coloring of the tongues of the gas stove burner. Inside the fire torch, there is a division into three zones:

A dark area located near the burner: there is no combustion due to lack of oxygen, and the temperature of the zone is 350 °.
A bright area lying in the center of the torch: the burning gas is heated to 700 °, but the fuel does not burn completely due to a lack of oxidizer.
Translucent upper section: reaches a temperature of 900°, and the combustion of the gas is complete.

The figures for the temperature zones of the fire torch are given for methane.

Fire Safety Rules

When kindling matches, a stove, take care of the ventilation of the room. Provide an oxygen supply to the fuel.

Do not attempt to repair gas equipment yourself. Gas does not tolerate amateurs.

Mistresses note that the burners glow blue, but sometimes the fire turns orange. This is not a global temperature change. The change in color is associated with a change in the composition of the fuel. Pure methane burns colorless and odorless. For security purposes in household gas sulfur is added, which, when burned, turns the gas blue and imparts a characteristic odor to the combustion products.

The appearance of orange and yellow hues in the fire of the burner indicates the need for preventive manipulations with the stove. Masters will clean the equipment, remove dust and soot, the burning of which changes the usual color of the fire.

Sometimes the fire in the burner turns red. This is a signal of a dangerous content of carbon monoxide in the supply of oxygen to the fuel is so small that the stove even goes out. Carbon monoxide is tasteless and odorless, and a person is near the source of emission harmful substance will notice too late that he was poisoned. Therefore, the red color of the gas requires the immediate call of the masters for the prevention and adjustment of equipment.

Both in everyday life and in professional repairs, portable gas burners are very popular. The scope of their application is very wide, and there are several varieties. You can choose the right burner for current tasks and learn how to use it correctly by studying this article.

The main types of portable burners

Gas burners in the form of nozzles for cylinders with a collet connection must be considered as a separate class of tool. They are used in high fire safety at sites where heavy construction equipment is not operating and the risk of damage to the burner itself is minimal.

First of all, burners are characterized by temperature and flame shape. The simplest devices have a combustion temperature close to the minimum, only 700-1000 °C. Air enters the burner naturally, so it is always in short supply. At the same time, more expensive products have a special form of air supply channels, due to this, the air flow increases, and the combustion temperature rises to 1200 ° C.

An even hotter flame is produced by ejector-type burners, in which air enters the hearth due to rarefaction, the flow force is directly proportional to the working gas pressure. This allows you to raise the temperature to 1500-1600 ° C and relatively smoothly adjust it along with the length of the flame by simply turning the tap. There may be several combustion centers in the burner; such a tool is not intended for fine workmanship, but perfectly warms up large areas.

The highest combustion temperature for burners is 2000-2400 °C and it is achieved due to the concentration of forced air in the combustion chamber and the use of a special gas: methyl acetylene propadiene (MAPP). A high-temperature cone is formed in the burner flame, comparable in power and temperature to oxy-fuel welding, but not capable of autogenous cutting.

Optionally, for all types of burners, it is possible to have a flexible or swivel tube, piezo ignition and a highly sensitive control valve. With a large temperature range, there is an equally wide range of burners in terms of power and corresponding gas flow.

Travel burners

Low-temperature burners solve a really wide range of tasks and are suitable for domestic use and professional construction. Such blowtorches are most often replaced by electric hair dryers in places where only autonomous operation is possible.

The main disadvantage of burners without an injector is the low flame stability, which is especially noticeable during sharp turns and tilts. Liquefied gas splashes do not have a significant effect in burners of a more expensive class with a special gearbox and heating circuit.

For soldering, such burners, as a rule, are not used. Their main purpose is to ignite firewood and coals or to heat materials that allow the use of an open flame. Such a tool is also indispensable for thawing pipes, heating car engines or unpacking squeegees on tow, firing paint to remove it and other rough work.

Blow Torches

Ejector blowtorches have a more specific device and purpose. These are the constant assistants of many designers and masters in the processing of non-ferrous metals. Due to their high temperature and flame control, the torches are ideal for brazing and hardening metals or other heat treatments that require high temperature accuracy and a well-defined cone.

Due to the specific application, the size of the burners and nozzles can vary greatly. Miniature ones are used for soldering jewelry and thin metal, despite the lack of pure oxygen supply, they even cope with filigree work. Medium range torches have a cone thickness of 3 to 9 mm and are best suited for electrical soldering of cable glands, copper and aluminum tubes.

Larger burners, due to their high power, are rational for use in industries such as artistic forging, precision bending or metal stamping. It is these tools that home craftsmen use as the basis for home-made gas furnaces and hardening furnaces.

For ejector burners, the concept of an unstable flame is purely figurative, and although periodic flashes of gas are possible, the core temperature remains relatively stable. The gas preheat circuit is used more to increase the efficiency of the burners, to bring them to operating power faster and to precisely control the temperature.

High temperature gas burners

It is impossible to ignore the burners, which use MAPP gas instead of a propane-butane mixture. The combustion temperature of the flame in them is 2200-2400 ° C, while the main energy is concentrated in the cone, which is quite stable and has a pronounced boundary.

Such burners are used for heating, forging and bending high-carbon steels and massive parts. The high temperature also makes it possible to quench and temper the metal more efficiently.

In terms of soldering and welding, MAPP gas torches do an excellent job with stainless steel, while even thin parts do not overheat. Another advantage of MAPP gas is its low boiling point, which makes it possible to use it at temperatures as low as -20 °C even in burners without a heating circuit.

Choosing the best option

When choosing a gas burner for various tasks, you should pay attention to certain nuances. For tourism purposes, the simplest naturally aspirated flare burners are well suited. Even cheap Chinese products can handle lighting a fire or heating food, it’s absolutely not a pity to break or lose them.

For domestic purposes and minor repairs, it is better not to purchase tools from an amateur series. Slightly more expensive semi-professional burners have a more thoughtful design and are devoid of such non-obvious flaws as, for example, melting of the plastic lining of the mouthpiece or malfunctioning piezo ignition. Another argument against the average price category- the almost universal absence of a normal control valve, which can be important even for rough work.

If the torch is chosen for fine work, soldering or welding, additional attention should be paid to ergonomics and balance. These jobs require the burner to be turned on and off frequently, so the shape of the body and placement of the controls must allow ignition and fine adjustments to be made with one hand.

When choosing power, you should be guided by the thickness and material of the workpieces. A burner of 500-700 W will be enough for burning paint or soldering copper wires. Non-ferrous metal tubes and steel products up to 3 mm thick will warm up well with a flame power of about 1200-1500 watts. 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 finer work, but it will not work to warm up a massive part with a low-power burner.

The purpose of this article is to tell you how to make a gas burner with your own hands. Gas burners in small business, individual technical creativity and in everyday life are used very widely for soldering, plumbing and blacksmithing, roofing, jewelry work, for starting heating appliances on gas and obtaining flames with a temperature of over 1500 degrees for various needs.

In the technological aspect, the gas flame is good in that it has a high reduction ability (cleanses the surface of the metal from impurities and restores its oxide to pure metal), without showing any noticeably different chemical activity.

In heat engineering, gas is a highly energy-intensive, relatively inexpensive and clean fuel; 1 GJ of gas heat is usually cheaper than from any other energy source, and coking and soot deposition in gas heaters is minimal or absent.

But at the same time, let's repeat the common truth: people don't joke with gas. A gas burner is not so complicated, but how to achieve its economy and safety - this will be discussed further. With examples of the correct technical performance and recommendations for making your own.

Choosing gas

With their own hands, an exclusively gas burner is made on propane, butane or a propane-butane mixture, those. on gaseous saturated hydrocarbons, and atmospheric air. When using 100% isobutane (see below), it is possible to achieve flame temperatures up to 2000 degrees.

Acetylene allows you to get a flame temperature of up to 3000 degrees, but due to its danger, the high cost of calcium carbide and the need for pure oxygen as an oxidizing agent, it has practically fallen into disuse in welding work. It is possible to obtain pure hydrogen at home; a hydrogen flame from a pressurized burner (see below) gives temperatures up to 2500 degrees. But the raw material for producing hydrogen is expensive and unsafe (one of the components is a strong acid), but the main thing is that hydrogen is not noticeable by smell and taste, it makes no sense to add a mercaptan flavor to it, because hydrogen spreads an order of magnitude faster, and its admixture with air in only 4% already gives explosive explosive gas, and its ignition can occur simply in the light.

Methane not used in domestic gas burners for similar reasons; in addition, it is highly poisonous. As for the vapors of flammable liquids, pyrolysis gases and biogas, when burned in gas burners, they give a not very clean flame with a temperature below 1100 degrees. Flammable liquids of medium and lower volatility (from gasoline to fuel oil) are burned in special liquid burners, for example, in burners for diesel fuel; alcohols - in low-power flame devices, and the ethers do not burn at all - they are low-energy, but very dangerous.

How to achieve security

To make a gas burner safe to use and not wasting fuel, the golden rule should be taken: no scaling and no changes to the prototype drawings at all!

Here the matter is in the so-called. the Reynolds number Re, showing the relationship between the flow rate, density, viscosity of the current medium and the characteristic size of the area in which it moves, for example. pipe cross section diameter. According to Re, one can judge the presence of turbulence in the flow and its nature. If, for example, the pipe is not round and both of its characteristic dimensions are greater than some critical value, then vortices of the 2nd and higher orders will appear. Physically distinguished walls of the “pipe” may not exist, for example, in sea currents, but many of their “tricks” are explained precisely by the transition of Re through critical values.

Note: just in case, for reference - for gases, the value of the Reynolds number, at which the laminar flow turns into turbulent, is Re> 2000 (in the SI system).

Not all homemade gas burners are accurately calculated according to the laws of gas dynamics. But, if you arbitrarily change the dimensions of parts of a successful design, then the Re of fuel or sucked air can jump beyond the limits that it adhered to in the author's product, and the burner will become smoky and voracious at best, and quite possibly dangerous.

Injector diameter

The determining parameter for the quality of a gas burner is the cross-sectional diameter of its fuel injector (gas nozzle, nozzle, jet - synonyms). For propane-butane burners at a normal temperature (1000-1300 degrees), it can be approximately taken as follows:

For thermal power up to 100 W - 0.15-0.2 mm.
For a power of 100-300 W - 0.25-0.35 mm.
For a power of 300-500 W - 0.35-0.45 mm.
For a power of 500-1000 W - 0.45-0.6 mm.
For a power of 1-3 kW - 0.6-0.7 mm.
For a power of 3-7 kW - 0.7-0.9 mm.
For a power of 7-10 kW - 0.9-1.1 mm.

In high-temperature burners, the injectors are made narrower, 0.06-0.15 mm. An excellent material for the injector is a piece of needle for a medical syringe or dropper; from them it is possible to pick up a nozzle on any of the specified diameters. Needles for inflating balls are worse, they are not heat resistant. They are used more like air ducts in supercharged micro-burners, see below. In the clip (capsule) of the injector, it is soldered with hard solder or glued with heat-resistant glue (cold welding).

Power

In no case should you make a gas burner with a power of more than 10 kW. Why? Let's say the efficiency of the burner is 95%; for an amateur design, this is a very good indicator. If the burner power is 1 kW, then it will take 50 watts to self-heat the burner. About 50 W soldering iron can get burned, but it does not threaten an accident. But if you make a 20 kW burner, then 1 kW will be superfluous, this is an iron or electric stove already left unattended. The danger is aggravated by the fact that its manifestation, like the Reynolds numbers, is threshold - either just hot, or flashes, melts, explodes. Therefore, it is better not to look for drawings of a home-made burner for more than 7-8 kW.

Note: industrial gas burners are produced with a capacity of up to many MW, but this is achieved by precise profiling of the gas barrel, which is impossible at home; see one example below.

fittings

The third factor determining the safety of the burner is the composition of its fittings and the manner in which it is used. IN general scheme is:

In no case should the burner be extinguished with a control valve, the fuel supply is stopped with a valve on the cylinder;
For burners with a power of up to 500-700 W and high-temperature ones (with a narrow injector that excludes the transition of the gas flow Re beyond the critical value), fed by propane or isobutane from a cylinder up to 5 liters at an outside temperature of up to 30 degrees, it is permissible to combine the control and shut-off valves in one - regular on the cylinder;
In burners with a power of more than 3 kW (with a wide injector), or powered by a cylinder of more than 5 liters, the probability of Re overshoot over 2000 is very high. Therefore, in such burners, between the shut-off and control valves, a gearbox is also required to maintain pressure in the supply gas pipeline within certain limits.

What to do?

Gas burners of low power for everyday life and small-scale private production are classified according to performance indicators as follows. way:

High-temperature - for precision welding, jewelry and glass work. Efficiency is not important, it is necessary to achieve the maximum flame temperature for a given fuel.
Technological - for metalwork and blacksmithing. The flame temperature is highly desirable not lower than 1200 degrees, and subject to this condition, the burner is brought to maximum efficiency.
Heating and roofing - achieve the best efficiency. The flame temperature is usually up to 1100 degrees or lower.

Regarding the method of fuel combustion, a gas burner can be made according to one of the following. schemes:

Free-atmospheric.
Atmospheric ejection.
Supercharged.

atmospheric

In free-atmospheric burners, the gas burns in free space; air flow is provided by free convection. Such burners are uneconomical, the flame is red, smoky, dancing and beating. They are of interest, firstly, because by excess gas supply or insufficient air, any other burner can be transferred to a free-atmospheric mode. It is in it that the burners are set on fire - at a minimum of fuel supply and even less air flow. Secondly, the free flow of secondary air can be very useful in the so-called. one and a half circuit burners for heating, because greatly simplifies their design without sacrificing safety, see below.

ejection

In ejection burners, at least 40% of the air required for fuel combustion is sucked in by the gas flow from the injector. Ejection burners are structurally simple and allow you to get a flame with a temperature of up to 1500 degrees with an efficiency of over 95%, therefore they are used most widely, but cannot be made modulating, see below. According to the use of air, ejection burners are divided into:

Single circuit - all the right air absorbed immediately. With a properly profiled gas duct, over 10kW of power show an efficiency of over 99%. With your own hands are not repeatable.
Dual circuit - approx. 50% of the air is sucked in by the injector, the rest goes into the combustion chamber and/or afterburner. They allow you to get either a flame of 1300-1500 degrees, or a CPL of over 95% and a flame of up to 1200 degrees. Used in any of the above ways. Structurally quite complex, but repeatable on their own.
One and a half circuit, often also called double circuit - the primary air is sucked in by the flow from the injector, and the secondary freely enters a limited volume (for example, a furnace furnace), in which the fuel burns out. Only single-mode (see below), but structurally simple, therefore widely used for temporary launch heating stoves and gas boilers.

supercharged

In pressurized burners, all air, both primary and secondary, is forced into the combustion zone of the fuel. The simplest supercharged micro burner for bench soldering, jewelry and glass work can be made by yourself (see below), but making a supercharged heating burner requires a solid manufacturing base. But it is the pressurized burners that make it possible to realize all the possibilities of controlling the combustion mode; According to the terms of use, they are divided into:

Single mode;
dual mode;
Modulated.

Combustion control

In single-mode burners, the fuel combustion mode is either determined once and for all constructively (for example, in industrial burners for annealing furnaces), or set manually, for which the burner must either be turned off or the technological cycle must be interrupted with its use. Two-stage burners usually operate at full or half power. The transition from mode to mode is carried out in the course of work or use. Heating burners (winter - spring / autumn) or roofing burners are made dual-mode.

In modulated burners, the supply of fuel and air is smoothly and continuously regulated by automation, which works out according to a set of critical initial parameters. For example, for a heating burner - according to the ratio of temperatures in the room, outdoor and coolant in the return. One output parameter is possible ( minimum flow gas, the highest flame temperature) or there may also be several of them, for example, when the flame temperature is at the upper limit, fuel consumption is minimized, and when it falls, the temperature is optimized for this process.

Design examples

Understanding the designs of gas burners, let's take the path of increasing power, this will allow us to better understand the material. And from the very beginning we will get acquainted with such an important circumstance as boost.

Mini from a can

It is well known how a single-mode mini gas burner for desktop work powered by a lighter refilling cartridge works: these are 2 needles inserted into each other, pos. And in Fig.:

Supercharging - from an aquarium compressor. Since it gives a noticeably pulsating flow under water without the resistance of the atomizer, a receiver of 5 liters of baklag is needed. Soda is not available in these, so the receiver plug will need to be additionally sealed with raw rubber, silicone or just plasticine. If you take a compressor for an aquarium of 600 liters or more, and the fuel is 100% isobutane (such cartridges are more expensive than usual), you can get a flame of over 1500 degrees.

The stumbling blocks in the repetition of this design, firstly, the adjustment of the gas supply. There are no problems with air - its supply is set by a standard compressor regulator. But adjusting the gas by bending the hose is very rough, and the regulator from the dropper quickly fails, it is disposable with it. Secondly, pairing the burner with the cartridge - in order for its valve to open, you need to press on the filling fitting

The first, the node shown in pos. will help solve problems. B; make it from the same pair of needles. First you need to pick up a piece of the tube for the sleeve, with a little effort fitting onto the nozzle of the can, and then, also with a little effort, push it into the cannula of the needle; it may need to be drilled out a bit. But the sleeve should not hang out either on the fitting or in the cannula separately.

Then we make a clip for the can with an adjusting screw (pos. B), insert the can, put the regulator on the fitting according to pos. B, and turn the screw until the desired gas supply is obtained. The adjustment is very precise, literally microscopic.

Soldering torches

The easiest way to make a soldering torch is approx. by 0.5-1 kW, if you have any gas valve available: an oxygen valve of the VK series, from an old autogen (the acetylene barrel is muffled), etc. One of the options for the design of a soldering torch based on a gas valve is shown in Fig.

Its peculiarity is the minimum number of turned parts, and even those can be selected ready-made, and there are quite wide possibilities for adjusting the flame by moving nozzle 11. The material of parts 7-12 is quite heat-resistant steel; in this case, the relatively inexpensive St45 is suitable, because. flame temperature due to total absence profiling of the gas channel and ejector windows (which do not exist as such) will not exceed 800-900 degrees. Also, due to the fact that this burner is single-circuit, it is rather voracious.

Dual circuit

A double-circuit gas burner for soldering is much more economical and allows you to get a flame up to 1200-1300 degrees. Examples of structures of this kind with power supply from a 5 l cylinder are given in Fig.

Burner on the left - for a power of approx. 1 kW, therefore, it consists of only 3 parts, not counting the gas barrel and handle, so a separate valve for adjusting the flame is not required. If desired, you can make interchangeable injector capsules for lower power; fuel consumption at low power will drop quite noticeably. The simplicity of the design in this case was achieved due to the use of a scheme with incomplete separation of air circuits: all air is sucked in through the holes in the housing, but part of it is carried away by the burning gas jet through a hole with a diameter of 12 mm into the afterburner.

Incomplete separation of the air circuits does not allow reaching a power of more than 1.2-1.3 kW: Re in the combustion chamber jumps “above the roof”, which causes combustion with pops up to an explosion, if you try to adjust the flame by giving gas. Therefore, without experience, it is better to put the injector into this burner 0.3-0.4 mm.

The burner with complete separation of air circuits, the drawings of which are given on the right in the figure, develops power up to several kW. Therefore, in its fittings, in addition to the shut-off valve on the cylinder, a control valve is also required. Together with the sliding primary ejector, it makes it possible to regulate the flame temperature within a fairly wide range, maintaining its minimum flow rate at a given power. In practice, having set the flame of the desired strength with a valve, the primary ejector is moved until a narrow blue jet (very hot) or a wide yellowish one (not so hot) flows.

For the forge and forge

Double-circuit torch with full separation of circuits, also suitable for blacksmithing. For example, how to build a horn from improvised materials for the one just described in 10-15 minutes, see the video:

Video: gas horn in 10 minutes

A metalwork-forge gas burner specifically for a forge can also be built according to a complete two-circuit scheme, see next. video clip.

Video: do-it-yourself gas burner for a forge

And finally, a mini gas burner can also heat a small tabletop horn; how to make them together yourself, see:

Video: do-it-yourself mini-horn at home

For fine work

Here in fig. drawings of a gas burner with a built-in control valve for particularly precise and demanding work are given. Its feature is a massive combustion chamber with cooling fins. Due to this, firstly, thermal deformations of the burner parts are reduced. Secondly, random jumps in the supply of gas and air practically do not affect the temperature in the combustion chamber. As a result, the installed flame is very stable for a long time.

high temperature

Finally, consider a burner designed to produce a flame of the highest possible temperature - on 100% isobutane naturally aspirated, this burner gives a flame with a temperature of more than 1500 degrees - it cuts sheet steel, melts any jewelry alloys in a mini crucible and softens any silicate glass, except quartz. A good injector for this burner is obtained from a needle from an insulin syringe.

Heating

If you are planning to switch your old stove or boiler from wood-coal to gas once and for all, then you have no other choice but to purchase a modulating pressurized burner, pos. 1 in fig. Otherwise, any savings on homemade products will soon be eaten up by excessive fuel consumption.

In the case when heating requires more than 12-15 kW of power and, in addition, there is a person who is ready and able to take on the duties of a stoker who regulates the gas supply according to the outside temperature, a double-circuit atmospheric burner for a boiler will be a cheaper option, the device diagram of which is given in pos. . 2. The so-called. Saratov burners, pos. 3; they are produced for a wide range of capacities, and have been successfully used in heat engineering for a long time.

If you need to stay on gas for some time, for example, until the end of the heating season, and then start a reconstruction of the heating system, or start on gas, for example, a country or bath stove, then for this a one and a half-loop gas burner can be made with your own hands for ovens. The scheme of its structure and operation is given in pos. 4. An indispensable condition - the furnace of the heater must be with a blower: if secondary air is allowed into the gap between the throat of the furnace and the burner body, fuel consumption will increase significantly. A drawing of a one and a half circuit gas burner for a furnace with a power of up to 10-12 kW is given in pos. five; oblong openings for primary air intake must be outside!

Roofing

A gas burner for roofing with modern built-up materials (roofing lamp) must be dual-mode: the underlying surface is heated at half power, and the coating is deposited at full power after the roll is unrolled. Delay is unacceptable here, so it is impossible to waste time on readjusting the burner (which is possible only after it has cooled down).

Roof gas burner device industrial production shown on the left in Fig. It is double-circuit according to the scheme with incomplete separation of circuits. In this case, such a solution is acceptable, because The burner runs at full power for approx. 20% of the process cycle time and is operated by trained personnel outdoors.

The most complex roof lamp assembly, which is unlikely to be repeated at home, is the power switching valve. However, it is possible to do without it at the cost of a slight increase in fuel consumption. If you are a master wagon and do roofing work occasionally, then the decrease in profitability due to this will not be noticeable.

Technically, this solution is implemented in a burner with coupled pairs of air circuits, see on the right in fig. The transition from mode to mode is carried out either by installing / removing the body of internal circuits, or simply by moving the lamp in height, because the operating mode of such a burner is highly dependent on the backpressure at the exhaust. To warm the underlying surface, the lamp is taken away from it, then a powerful wide stream of not excessively hot gases will come out of the nozzle. And for surfacing, the lamp is brought closer: roofing material a wide "pancake" of flame will spread.

Finally

In this article, only selected examples of gas burners are considered. The total number of their designs only for the "home" power range up to 15-20 kW is in the hundreds, if not thousands. But let's hope that some of the ones described here will come in handy for you.