Galvanized steel ventilation is a universal solution. Dimensions and installation rules for ventilation ducts Air duct manufacturing technology description drawings

The production of air ducts is a profitable business. They are needed in the construction of residential and commercial premises. Air ducts are structures resembling pipes that distribute the flow of incoming and exhaust air. Ventilation pipes are also used for these purposes. The article will discuss air ducts made of galvanized steel and other materials.

How to start an air duct manufacturing business?

We study the range

There are several types of air ducts. They are:

• rigid and flexible;
• round or rectangular;
• steel (stainless or galvanized steel), plastic, aluminum, rubber, fabric (polyester), silicone, fiberglass;
• connecting (able to be fastened together using nipples or fasteners);
• fire retardant.

Manufacturing technology depends on the type of raw materials used in production.

Galvanized steel and aluminum are the materials with which the most labor-intensive of all production methods is carried out. ventilation ducts which are used in restaurants, schools, shopping malls, offices. Steel products have the following advantages:

• they are not susceptible to corrosion;
• cheaper than plastic;
• fire resistant;
• amenable to quick dismantling.

Flexible ducts for ventilation are more difficult to produce. They are installed in small buildings where it is necessary to remove harmful substances in the air. They also come in two shapes: round and rectangular. It takes a lot to produce them. Money. But they are in the highest demand. Therefore, experienced entrepreneurs say that it is better to start manufacturing ventilation ducts from this particular type.

Weigh the pros and cons

The main advantages can be identified:

• Yield. Despite the fact that this business requires a lot of investment, it brings great profits if developed in the right direction.
• High demand. No building is complete without air ducts. And every year, especially in metropolitan areas, more and more multi-storey buildings are being built. They are also needed by those who make repairs and change the communication system. Therefore, there is always a customer for air ducts.
• Year-round production. Since the business is not seasonal, management can sell goods to other regions.
• High payback. In a year, a skilled entrepreneur will be able to help out the amount that will cover all initial expenses.

The cons include:

• large investment investments;
• high level of competition.

Before opening own production, you need to assess the market situation in your region, conduct an analysis of competitors. This business is fraught with many features that can have a negative impact on the enterprise as a whole.

How to choose equipment for the production of air ducts?

The technical equipment of the plant is selected taking into account the area and cross-sectional shape of the pipes, their rigidity. Which air ducts to produce in terms of size and parameters is decided by the owner of the enterprise, based on consumer demand.

Also, the main indicator of the type of manufactured products is installation. So, rectangular ducts lend themselves to this process worse than round ones, which have another significant advantage. They are easier to produce due to the fact that they are connected using snap nipples.

But they also have disadvantages - quality. Rectangular ducts are more reliable ventilation structures. They are used for large cross-sectional areas. When Difficult Expectations installation work in a building with an unusual design, they also prefer rectangular ducts.

Since it is not known which types of products will be more in demand in your area, it is better to purchase two machines that can work with both rectangular and round structures.

Equipment for the production of air ducts:

• guillotine;
• machines that correct the shape of the sheet;
• a machine that is responsible for feeding raw materials to the main line;
• an apparatus capable of unwinding sheets made of metal from rolls;
• CNC system.

The equipment intended for the production of air ducts of various shapes does not differ much from each other. To create round structures, rollers (rolling) are used, and for rectangular structures, machines, bending sheets and applying ribs.

Machines for the manufacture of round air ducts will cost no less than 3 million rubles, and for rectangular ducts - 3.5-5 million rubles.

Documents required for organizing a business

Production of air ducts - direction commercial activities, does not require licenses or special permits. For legal work, it is enough to register as an individual entrepreneur or open an LLC. The first option is cheaper and easier in terms of preparing all the necessary papers. But with IP very rarely work serious companies who are interested in large volumes finished products. Another disadvantage is that in the event of bankruptcy, the entrepreneur ( individual) may lose their personal property, and the founders of an LLC risk only the authorized capital and funds of the company.

In order to draw up IP documents, you need to pay a state fee, write an application, make copies of the TIN and passport, and then transfer all this to the tax inspector. The founders of an LLC need to additionally prepare the statutory documents of the company, resolve the issue of legal address and form statutory fund(from 10 thousand rubles).

Regardless of the choice of legal form for your business, you need to choose a code that matches your activity. In this case, it is OKVED 28.1.

What tax regime can duct manufacturers choose?

If a we are talking about small volumes of production, then you can work on a simplified regime, which provides for mandatory payments to the state in the amount of 6% of profits or 15% of gross income.

If you decide to organize a large-scale production of air ducts and plan to enter into contracts with large companies, then it is better for you to work on a general basis. In order to organize internal and tax accounting in this situation, a qualified accountant is needed, who must be paid a rather large salary. But a good specialist will always find legal ways reduce the amount tax payments, often exceeding the monetary reward for their work.

Air duct production technology

The production of air ducts takes place in several stages. Let us consider in more detail the production process of one of the types of round structures made of galvanized steel.

The entire production process is automated. The quality of finished products depends on the condition of the purchased machines.

How much money do you need to start a business?

Setting up this type of business requires a large initial investment. The main costs include:

• Purchase of equipment for the manufacture of air ducts of various shapes - 6-7 million rubles.
• Room rental - 50 thousand rubles.
• Salary - 50 thousand rubles.

If there are no funds to create a full-scale production, then you can start with the manufacture of parts needed for ventilation ducts. These include:

• plugs;
• bends;
• tie-ins;
• nipples.

This will not require large expenses, since all these structures can be made from industrial waste and defective products. Machine tools for their manufacture cost within 50 thousand rubles. Subsequently, you can expand the scope of activities and begin to manufacture various types of air ducts themselves.

To save money, you can hire unqualified staff for the first time. Naturally, you need to take care of the quality of the goods, so you should take into account the abilities of employees.

How much can you earn in the production of air ducts?

This business is very profitable. This allows you to get a large profit at a relatively low initial cost. With well-established production, you can get about 200-400 thousand rubles. per month, given that the market price for one meter of air duct varies between 300-600 rubles. The cost depends on the diameter of the pipe (outer).

With intensive work, the initial costs will pay off in 6-12 months.

The manufacture of air ducts is a great business idea for a novice entrepreneur who is looking for a field of activity in which he would like to realize himself. There is always a risk of burnout, but in this case you should not be afraid of this, because not a single room can do without ventilation.

INTRODUCTION

Welding, along with casting and pressure treatment, is the oldest technological operation mastered by man in the Bronze Age during the acquisition of experience in working with metals. Its appearance is associated with the need to connect various parts in the manufacture of tools, military weapons, jewelry and other products.

The first method of welding was forge, which provided a fairly high quality connection at that time, especially when working with ductile metals such as copper. With the advent of bronze (harder and harder to forge), foundry welding arose. During foundry welding, the edges of the parts to be joined were molded with a special earthen mixture and poured with heated liquid metal. This filler metal was fused with the parts and solidified to form a seam. Such compounds have been found on bronze vessels preserved from the times of Ancient Greece and Ancient Rome.

With the advent of iron, the range of metal products used by man increased, so the scope and scope of welding expanded. New types of weapons are being created, the means of protecting a warrior in battle are being improved, chain mail, helmets, and armor are appearing. For example, in the manufacture of chain mail, more than 10 thousand metal rings had to be connected by forge welding. New casting technologies are being developed, knowledge is gradually being acquired related to the heat treatment of steel and giving it different hardness and strength. Often this knowledge was obtained by chance and could not explain the essence of the ongoing processes.

For example, in a manuscript found in the temple of Balgon in Asia, the process known to us as tempering steel is described as follows: "Heat the dagger until it glows like the morning sun in the desert, then cool it to the color of royal purple, sticking the blade into the body muscular slave. The strength of the slave, turning into a dagger, gives it hardness. " Nevertheless, despite the rather primitive knowledge, swords and sabers were made even before our era, which had unique properties and were called Damascus. In order to give the weapon high strength and hardness and at the same time provide plasticity that did not allow the sword to be fragile and break from blows, it was made layered. Alternately, in a certain sequence, hard layers of medium or high carbon steel and soft strips of low carbon steel or pure iron were welded together. The result was a weapon with new properties that cannot be obtained without the use of welding. Subsequently, in the Middle Ages, this technology began to be used for the manufacture of highly efficient, self-sharpening plows and other tools.

Forge and foundry welding for a long time remained the main method of joining metals. These methods fit well into the production technology of that time. The profession of a blacksmith-welder was very honorable and prestigious. However, with the development in the XVIII century. machine production, the need to create metal structures, steam engines, and various mechanisms has increased dramatically. Known methods of welding in many cases ceased to meet the requirements, since the lack of powerful heat sources did not allow uniform heating of large structures to the temperatures required for welding. Riveting became the main method of obtaining permanent joints at that time.

The situation began to change at the beginning of the 20th century. after the creation of sources of electrical energy by the Italian physicist A. Volta. In 1802, the Russian scientist V.V. Petrov discovered the phenomenon of an electric arc and proved the possibility of using it to melt metal. In 1881 Russian inventor N.N. Benardos proposed using an electric arc burning between a carbon electrode and a metal part to melt its edges and connect it to another part. He called this method of joining metals "electrohephaestus" in honor of the ancient Greek blacksmith god. It became possible to connect metal structures of any size and various configurations with a strong welded seam. This is how electric arc welding appeared - an outstanding invention of the 19th century. It immediately found application in the most difficult industry at that time - steam locomotive building. Discovery of N.N. Bernardos in 1888 was improved by his contemporary N.G. Slavyanov, replacing the non-consumable carbon electrode with a consumable metal one. The inventor proposed the use of slag, which protected the weld from air, making it more dense and durable.

In parallel, gas welding developed, in which a flame was used to melt the metal, which was formed during the combustion of a combustible gas (for example, acetylene) mixed with oxygen. AT late XIX in. this method of welding was considered even more promising than arc welding, since it did not require powerful sources of energy, and the flame, simultaneously with the melting of the metal, protected it from the surrounding air. This made it possible to obtain a sufficiently good quality of welded joints. Around the same time, thermite welding began to be used to connect railroad joints. During the combustion of thermites (a mixture of aluminum or magnesium with iron oxide), pure iron is formed and a large amount of heat is released. A portion of thermite was burned in a refractory crucible, and the melt was poured into the gap between the welded joints.

An important stage in the development of arc welding was the work of the Swedish scientist O. Kelberg, who in 1907 proposed to apply a coating to a metal electrode, which, decomposing during arc burning, provided good protection of the molten metal from air and its alloying with the elements necessary for high-quality welding. After this invention, welding began to find more and more applications in various industries. Of particular importance at that time were the works of the Russian scientist V.P. Vologdin, who created the first department of welding at the Polytechnic Institute of Vladivostok. In 1921 on Far East the first welding workshop for the repair of ships was opened; in 1924, the largest bridge across the Amur River was repaired using welding. At the same time, tanks for storing oil with a capacity of 2000 tons were created, a generator for the Dneproges was manufactured by welding, which was twice as light as riveted. In 1926, the first All-Union Conference on Welding was held. In 1928, there were 1,200 arc welding units in the USSR.

In 1929, a welding laboratory was opened in Kyiv at the Academy of Sciences of the Ukrainian SSR, which in 1934 was transformed into the Institute of Electric Welding. The institute was headed by a well-known scientist in the field of bridge construction, Professor E.O. Paton, after whom the institute was later named. One of the first major works Institute was the development in 1939 of automatic submerged arc welding. It made it possible to increase the productivity of the welding process by 6-8 times, improve the quality of the joint, significantly simplify the work of the welder, turning him into an operator for controlling the welding installation. This work of the Institute in 1941 received the State Prize. Submerged arc welding played a huge role during the Great Patriotic War, for the first time in the world becoming the main method of joining armor plates up to 45 mm thick in the manufacture of the T34 tank and up to 120 mm in the manufacture of the IS-2 tank. With a shortage of qualified welders during the war, the increase in welding productivity through automation made it possible to short term significantly increase the production of tanks for the front.

A significant achievement of welding science and technology was the development in 1949 of a fundamentally new method of fusion welding, called electroslag welding. Electroslag welding plays a huge role in the development of heavy engineering, as it allows welding very thick metal (more than 1 m). An example of the use of electroslag welding is the manufacture of machine-building plant commissioned by France, a press that can generate a force of 65,000 tons. The press has a height equal to the height of a 12-story building, and its weight is twice that of the Eiffel Tower.

In the 50s. of the last century, industry has mastered the method of arc welding in a carbon dioxide environment, which has recently become the most common welding method and is used in almost all machine-building enterprises.

Welding is actively developing in subsequent years. From 1965 to 1985, the volume of production of welded structures in the USSR increased 7.5 times, the stock of welding equipment - 3.5 times, the output of welding engineers - five times. Welding began to be used for the manufacture of almost all metal structures, machines and structures, completely replacing riveting. For example, the usual a car has more than 5 thousand welded joints. The pipeline, which supplies gas from Siberia to Europe, is also a welded structure with more than 5,000 kilometers of welds. Not a single high-rise building, TV tower or nuclear reactor is manufactured without welding.

In the 70-80s. new methods of welding and thermal cutting are being developed: electron beam, plasma, laser. These methods make a huge contribution to the development of various industries. For example, laser welding allows you to qualitatively connect the smallest parts in microelectronics with a diameter and thickness of 0.01-0.1 mm. The quality is ensured by the sharp focusing of the monochromatic laser beam and the finest dosage of the welding time, which can last from 10 to 6 seconds. Mastering] laser welding made it possible to create a whole series of new element base, which in turn made it possible to manufacture new generations of color televisions, computers, control and navigation systems. Electron-beam welding has become an indispensable technological process in the manufacture of supersonic aircraft and aerospace facilities. The electron beam makes it possible to weld metals up to 200 mm thick with minimal structural deformations and a small heat-affected zone Welding is the main technological process in the manufacture sea ​​vessels, platforms for oil production, submarines. The modern nuclear submarine, which is about 200 m high and 12-storey high, is a fully welded structure made of high-strength steels and titanium alloys.

Without welding, the current achievements in the space field would not have been possible. For example, final assembly missile system carried out in a welded assembly shop weighing about 60 thousand and 160 m high. The rocket containment system consists of welded towers and masts with a total weight of about 5 thousand tons. All critical structures on the launch pad are also welded. Some of them have to work in very difficult conditions. The impact of a powerful flame at the launch of a rocket takes on a welded flame separator weighing 650 tons, 12 m high. Complex welded structures are fuel storage tanks, a system for supplying it to tanks and the fuel tanks themselves. They must withstand enormous hypothermia. For example, a liquid oxygen tank has a capacity of over 300,000 liters. It is made with a double wall - from stainless and low carbon steel. The diameter of the outer sphere is 22 m. Tanks for liquid hydrogen are designed in a similar way. The pipeline for supplying liquid hydrogen is welded from nickel alloy, it is inside another aluminum alloy pipeline. The pipelines for supplying kerosene and superactive fuel are welded from stainless steel, and the pipeline for supplying oxygen is made of aluminum.

With the help of welding, multi-ton BelAZs and MAZs, tractors, trolleybuses, elevators, cranes, scrapers, refrigerators, televisions and other industrial products and consumer goods are manufactured.

1. TECHNOLOGICAL SECTION

1 Description of the welded structure and its purpose

The fan housing works in particularly harsh conditions. Subjected to direct impact of dynamic and vibration loads.

The fan housing is made up of

Pos 1 Body 1 pc

V \u003d π * D * S * H ​​\u003d 3.14 * 60.5 * 0.8 \u003d 151.98 cc.

Q \u003d ρ * V \u003d 7.85 * 151.98 \u003d 1193.01 gr. = 1.19 kg

Pos 2 Flange 2 pcs.

fan welding deformation arc

V \u003d π * (D out 2. - D int 2) * s \u003d 3.14 * (64.5 2 -60.5 2) * 1 \u003d 1570 cu. cm

Q \u003d ρ * V \u003d 7.85 * 1570 \u003d 12324.5 gr. = 12.33 kg.

Pos 3 Ear 2 pcs

V \u003d h + l + s \u003d 10 * 10 * 0.5 \u003d 50 cu. cm

Q \u003d ρ * V \u003d 7.85 * 50 \u003d 392.5 g \u003d 0.39 kg

Cross-sectional area of ​​the weld

t. sh. \u003d 0.5K² + 1.05K \u003d 0.5 * 6² + 1.05 * 6 \u003d 24.3 sq mm

2 Weldment material justification

Chemical composition of steel

Equivalent carbon content

Ce \u003d Cx + Cp

Сх - chemical equivalent of carbon

Сх = С + Mn/9 + Cr/9 + Mo/12 = 0.16 +1.6/9 + 0.4/9 = 0.38

Ср - correction to carbon equivalent

Cp \u003d 0.005 * S * Cx \u003d 0.005 * 8 * 0.38 \u003d 0.125

Preheat temperature

T p \u003d 350 * \u003d 350 * 0.25 \u003d 126.2 degrees.

1.3 Specifications for the manufacture of welded structures

The fan housing works in particularly harsh conditions. Subjected to direct impact of dynamic and vibration loads.

4 Determining the type of production

The total weight of the spar is 32.07 kg. With a production program of 800 pcs, we select the serial type of production

In mass production, the type of production is characterized by the use of specialized assembly and welding fixtures, welding of units is carried out on stationary workers

5 Selection and justification of assembly and welding methods

This design is made of 16G2AF steel, which belongs to the group of well-welded steels. When welding, preheating up to 162 degrees and subsequent heat treatment is required.

Steel is welded by all types of welding. The thickness of the parts to be welded is 10 mm, which allows welding in a carbon dioxide environment with wire Sv 08 G2S

1.6 Determination of welding modes

sv \u003d h * 100 / Kp

where: h - penetration depth

Kp - coefficient of proportionality

c in \u003d 0.6 * 10 * 100 / 1.55 \u003d 387 A

Arc voltage

20 + 50* Ib* 10⁻³ / d⁰² V

20 + 50 *387 *10 ⁻³ / 1.6⁰² = 20 + 15.35 = 35.35 V

Welding speed

V sv \u003d K n * I sv / (ρ * F * 100) m / h =

1*387/7.85*24.3*100 = 34.6 m/h

where K n - surfacing coefficient g / A * h

ρ is the density of the metal, adopted for carbon and low alloy steels equal to 7.85 g/cm3;

F is the cross-sectional area of ​​the deposited metal. mm 2

7 Selection of welding consumables

Steel 16G2AF is welded by any type of welding using various kinds welding materials. Therefore, we use wire SV 08 G 2 S for welding. SV 08 G2S wire has good weldability, low emission of welding fumes, and low price.

7.1 Consumption of welding consumables

The consumption of electrode wire when welding in CO2 is determined by the formula

G e. pr. \u003d 1.1 * M kg

M - mass of deposited metal,

M = F * ρ * L * 10 -3 kg

M t. sh. \u003d 0.243 * 7.85 * 611.94 * 10 -3 \u003d 1.16 kg

Consumption of electrode wire

G e. pr. \u003d 1.1 * M \u003d 1.1 * 1.16 \u003d 1.28 kg

Consumption of carbon dioxide

G co2 \u003d 1.5 * G e. pr. \u003d 1.5 * 1.28 \u003d 1.92 kg

Electricity consumption

W \u003d a * G e. etc. \u003d 8 * 1.28 \u003d 10.24 kW / h

a \u003d 5 ... 8 kW * h / kg - specific energy consumption per 1 kg of deposited metal

8 Selection of welding equipment, technological equipment, tools

MAGSTER WELDING SYSTEM

· Professional welding system with the taken-out 4th roller giving mechanism of the well-known quality Lincoln Electric at the price of the best Russian analogues.

· Welding in shielding gases with solid and flux-cored wires.

· With success it is applied to welding of structural low-carbon and stainless steels, and also to welding of aluminum and its alloys.

· Step-by-step welding voltage adjustment.

· Smooth adjustment of giving of a wire.

· Gas pre-purging.

· Thermal overload protection.

· Digital voltage indicator.

· High reliability and easy operation.

· Synergic system of the welding process - after loading the type of wire and diameter, the feed rate and voltage are matched automatically by the microprocessor, (for mod. 400,500).

· Many functional liquid crystal display - displaying the parameters of the welding process (for mod. 400, 500).

· Water cooling system (for models with index W) .

· All models are equipped with a socket for connecting a gas heater (the heater is supplied separately).

· Designed in accordance with IEC 974-1. Protection class IP23 (outdoor operation).

· Supplied as ready-to-use kits and include: power source, feeder with transport trolley, connecting cables 5 m, mains cable 5 m, welding torch "MAGNUM" 4.5 m long, work clamp.

· AGSTER 400 plus MAGSTER 500 w plus MAGSTER 501 w Maximum power consumption, mains 380 V. 14.7 kW. 17 kW. 16 kW. 24 kW. 24 kW. Welding current at 35% duty cycle. 315 A. 400 A. 400 A. 500 A. 500 A. Welding current at 60% duty cycle. 250 A. 350 A. 350 A. 450 A. 450 A. Welding current at 100% duty cycle. 215 A. 270 A. 270 A. 350 A. 450 A. Output voltage. 19-47 V. 18-40 V. 18-40 V. 19-47 V. 19-47 V. Weight without cables. 88 kg 140 kg 140 kg 140 kg 140 kg

TECHNICAL PARAMETERS OF THE WIRE FEEDER

· Wire feed speed. 1-17 m/min 1-24 m/min 1-24 m/min 1-24 m/min 1-24 m/min Wire diameters. 0.6-1.2 mm 0.8-1.6 mm 0.8-1.6 mm 0.8-1.6 mm 0.8-1.6 mm Weight without torch. 20 kg. 20 kg. 20 kg.

9 Determination of technical standards for assembly and welding times

Calculation of technical norms of assembly time and assembly welding.

		Parameter	Time limit min	Time min	Source
	Clean the places for welding from oil, rust and other contaminants.		0.3 per 1 m of the seam
	Install child pos 2 in fixture.	Children's weight 12.33 kg
	Set children pos. 1 on det pos 2
	Grab det poses 1 to det poses 3 for 3 potholders		0.09 1 tack
	Set children pos. 2 on det pos 1	Children's weight 12.33
	Grab det poses 2 to det poses 1 for 3 potholders		0.09 1 tack
	Install 2 children pos. 3 on det pos 1	Children's weight 0.39
	Grab 2 det pos 3 to det pos 1 for 4 potholders		0.09 1 tack
	Remove the assembly unit and put it on the table of the welder	Sat weight units 32.07 kg
		L seam = 1.9 m	1.72 min / m seam
	Weld the edges of children pos 1 to each other	L seam = 0.32 m	1.72 min / m seam
	Weld child pos 2 to child pos 1	L seam = 1.9 m	1.72 min / m seam
	Clean the weld seam from spatter.	Lzach = 4.12 m	0.4 min/m seam
	Worker control, foreman
	Remove assembly unit

Table 1

table 2

Time to install parts (assembly units) when assembling metal structures for welding

Assembly view	Part weight, assembly unit
fixator

Table 3

Tack time

Thickness of metal or legs, mm	Tack length, mm	Time for one tack, min

Time to remove assembly units from the fixture and put them into storage

Basic time for welding 1 m. seam

F - cross-sectional area of ​​the weld

ρ - specific density of the deposited metal, g / cu. cm.

a - deposition coefficient

a \u003d 17.1 g / a * hour

That. t.sh = = 1.72 min / 1 m seam

10 Calculation of the amount of equipment and its loading

Estimated amount of equipment

C p = = = 0.09

T gi - the annual complexity of the operation, n-hour;

T gi = = = 308.4 n-hour

F d o - annual actual fund of equipment operation

F d o \u003d (8 * D p + 7 * D s) * n * K p \u003d (8 * 246 + 7 * 7) * 2 * 0.96 \u003d 3872.6 hours

D p, D s - the number of working days per year, respectively, with full duration and reduced;

n is the number of work shifts per day;

K p - coefficient taking into account the time the equipment is under repair (K p \u003d 0.92-0.96).

Load factor

K z = = = 0.09

Cp is the estimated amount of equipment;

Spr - accepted amount of equipment Spr = 1

11 Calculation of the number of employees

The number of main workers directly involved in the performance of technological operations is determined by the formula

Ch o.r. ===0.19

T g i - annual labor intensity, n-hour;

F d r - the annual actual fund of the working time of one worker, in hours;

K in - coefficient of performance of production standards (K in \u003d 1.1-1.15)

Annual effective fund of working time of one worker

F dr \u003d (8 * D p + 7 * D s) * K nev \u003d (8 * 246 + 7 * 7) * 0.88 \u003d 1774.96 hours

where D p, D s - the number of working days per year, respectively, with full duration and reduced;

K nev - absenteeism coefficient for good reasons (K nev = 0.88)

12 Methods for dealing with welding deformations

The whole complex of measures to combat deformations and stresses can be divided into three groups:

Activities that are implemented before welding;

Activities in the welding process;

Activities carried out after welding.

Deformation control measures applied before welding are implemented at the design stage of the welded structure and include the following measures.

Structural welding should have a minimum amount of deposited metal. The legs should not exceed the design values, butt welds should be made without cutting edges, if possible, the number and length of welds should be the minimum allowable.

It is necessary to use welding methods and modes that provide minimal heat input and a narrow heat-affected zone. In this regard, welding in CO 2 is preferable manual welding, and electron beam and laser welding is preferable to arc welding.

Welds should be as symmetrical as possible on the welded structure, it is not recommended to place welds close to each other, to have a large number of intersecting seams, without the need to use asymmetrical grooves. In structures with thin-walled elements, it is advisable to place the seams on rigid elements or near them.

In all cases where there is concern that undesirable deformations will occur, the design is carried out in such a way as to ensure the possibility of subsequent straightening.

Measures used in the welding process

Rational sequence of applying welds, on the structure and along the length.

When welding alloy steels and steels with a high carbon content, this can lead to the formation of cracks, so the stiffness of the fasteners must be assigned taking into account the metal being welded.

Preliminary deformation of welded parts.

Compression or rolling of the weld, which is carried out immediately after welding. In this case, the zone of plastic deformations of the shortening is subjected to plastic upsetting along the thickness.

1.13 Choice of quality control methods

The operational control system in welding production includes four operations: control of preparation, assembly, welding process and welded joints.

.) Control of the preparation of parts for welding

It provides for the control of the processing of the front and back surfaces, as well as the end edges of the parts to be welded.

The surfaces of the edges to be welded must be cleaned from dirt, preservative grease, rust and scale, to a width of 20 - 40 mm from the joint.

.) Assembly - installation of the parts to be welded in the appropriate position relative to each other when welding tee joints control the perpendicularity of the parts to be welded. When checking the quality of tacks, attention should be paid to the condition of the surface and the height of the tacks.

.) Welding process control includes visual observation of the process of metal melting and weld formation, control of the stability of the mode parameters and equipment performance.

.) Inspection of welded joints. After welding welded joints usually controlled visually. The weld and the heat-affected zone are subjected to inspection. Usually the control is carried out with the naked eye. When detecting surface defects less than 0.1 mm in size, optical devices are used, for example, a magnifier of 4-7 times magnification.

The main structural elements of welds are:

seam width

height of reinforcement and penetration;

smooth transition from reinforcement to base metal, etc.

1.14 Safety, fire prevention and environmental protection

The harmful effects of welding and thermal cutting on a person and industrial injuries during welding are caused by various reasons and can lead to temporary disability, and in unfavorable circumstances, to more serious consequences.

Electric current is dangerous to humans, and alternating current is more dangerous than direct current. The degree of danger of electric shock depends mainly on the conditions for including a person in the circuit and the voltage in it, since the strength of the current flowing through the body is inversely proportional to the resistance (according to Ohm's law). For the minimum design resistance of the human body, 1000 ohms are taken. There are two types of electric shock: electric shock and trauma. With an electric shock, the nervous system, muscles of the chest and ventricles of the heart are affected; paralysis of the respiratory centers and loss of consciousness are possible. Electrical injuries include burns to the skin, muscle tissues, and blood vessels.

The light radiation of the arc acting on unprotected organs of vision for 10-30 s within a radius of up to 1 m from the arc can cause severe pain, lacrimation and photophobia. Prolonged exposure to arc light under such conditions can lead to more serious diseases - (electrophthalmia, cataracts). Harmful effect rays of the welding arc affect the organs of vision at a distance of up to 10 m from the place of welding.

Harmful substances (gases, vapors, aerosol) are released during welding as a result of physical and chemical processes that occur during the melting and evaporation of the metal being welded, components of electrode coatings and welding fluxes, as well as due to the recombination of gases under the action of high temperature welding heat sources. The air environment in the welding zone is polluted by welding aerosol, which consists mainly of oxides of welded metals (iron, manganese, chromium, zinc, lead, etc.), gaseous fluorine compounds, as well as carbon monoxide, nitrogen oxides and ozone. Prolonged exposure to welding aerosol can lead to occupational intoxication, the severity of which depends on the composition and concentration of harmful substances.

The explosion hazard is due to the use of oxygen, shielding gases, combustible gases and liquids in welding and cutting, the use of gas generators, compressed gas cylinders, etc. Chemical compounds of acetylene with copper, silver and mercury are explosive. The danger is backstroke in the gas network when working with low-pressure burners and cutters. When repairing used tanks and other containers for storing flammable liquids, special measures are necessary to prevent explosions.

Thermal burns, bruises and injuries are caused by the high temperature of the welding heat sources and significant heating of the metal during welding and cutting, as well as limited visibility of the surrounding space in connection with the production of work using shields, masks and goggles with light-protective glasses.

Unfavorable meteorological conditions affect welders (carvers) - builders and assemblers for more than half the time of the year, since they have to work mainly in the open air.

The increased fire hazard during welding and cutting is due to the fact that the melting point of metal and slag significantly exceeds 1000 ° C, and liquid combustible substances, wood, paper, fabrics and other flammable materials ignite at 250-400 ° C.

2. ELECTRICAL SAFETY PRECAUTIONS

Chassis must be grounded securely welding machine or installations, clamps of the secondary circuit of welding transformers used to connect the return wire, as well as welded products and structures.

2. It is forbidden to use ground loops, pipes of sanitary facilities, metal structures of buildings and technological equipment. (During construction or repair, metal structures and pipelines (without hot water or explosive atmosphere) can be used as a return wire of the welding circuit and only in cases where they are welded.)

4. It is necessary to protect the welding wires from damage. When laying welding wires and each time they are moved, prevent damage to the insulation; contact of wires with water, oil, steel ropes, sleeves (hoses) and pipelines with combustible gases and oxygen, with hot pipelines.

Flexible electric wires for controlling the scheme of the welding installation, with their considerable length, must be placed in rubber sleeves or in special flexible multi-link structures.

6. Only electrical personnel are entitled to repair welding equipment. Do not repair live welding equipment.

When welding in especially dangerous conditions (inside metal containers, boilers, vessels, pipelines, in tunnels, in closed or basement rooms with high humidity, etc.):

welding equipment must be outside of these containers, vessels, etc.

electric welding installations must be equipped with a device for automatically shutting off the open circuit voltage or limiting it to a voltage of 12V for no more than 0.5 s after welding is stopped;

allocate a safety worker, who must be outside the tank, to monitor the safety of the welder. The welder is provided with a mounting belt with a rope, the end of which must be at least 2 m long in the hands of the insurer. Near the insurer there should be a device (knife switch, contactor) to turn off the mains voltage from the power source of the welding arc.

Should not be allowed to arc welding or cutting welders in wet gloves, shoes and overalls.

9. Cabinets, consoles and beds of contact welding machines, inside which there is equipment with open current-carrying parts under voltage, must have a lock that provides voltage relief when they are opened. Pedal start buttons of contact machines must be grounded and the reliability of the upper guard, which prevents involuntary switching on, must be monitored.

10. In case of electric shock, you must:

urgently turn off the current with the nearest switch or separate the victim from current-carrying parts using dry improvised materials (pole, board, etc.) and then put him on a litter;

immediately call for medical assistance, given that a delay of more than 5-6 minutes can lead to irreparable consequences;

if the victim is unconscious and breathless, release him from tight clothing, open his mouth, take measures against falling of the tongue and immediately begin artificial respiration, continuing it until the doctor arrives or normal breathing is restored.

3. PROTECTION AGAINST LIGHT RADIATION

To protect the eyes and face of the welder from the light radiation of an electric arc, masks or shields are used, into the viewing holes of which protective glass filters are inserted that absorb ultraviolet rays and a significant part of light and infrared rays. From splashes, drops of molten metal and other contaminants, the light filter is protected from the outside with ordinary transparent glass installed in the viewing hole in front of the light filter.

Light filters for arc welding methods are selected depending on the type of welding work and the welding current, using the data in Table. 3. When welding in a shielding inert gas environment (especially when welding aluminum in argon), it is necessary to use a darker light filter than when welding with an open arc at the same current strength.

Table 3. Light filters for eye protection from arc radiation (OST 21-6-87)

2. To protect the surrounding workers from the light radiation of the welding arc, portable shields or screens made of fireproof materials are used (with a non-permanent workplace of the welder and large products). In stationary conditions and with relatively small sizes of welded products, welding is performed in special booths.

3. To reduce the contrast between the brightness of the arc light, the surface of the walls of the workshop (or cabins) and equipment, it is recommended to paint them in light colors with diffuse reflection of light, and also to ensure good illumination of the surrounding objects.

If the eyes are damaged by the light radiation of the arc, you should immediately consult a doctor. If it is not possible to obtain a fast medical care make lotions on the eyes with a weak solution of baking soda or tea leaves.

Protection against harmful gas emissions and aerosol

To protect the body of welders and cutters from harmful gases and aerosols released during the welding process, it is necessary to use local and general ventilation, supply clean air to the breathing zone, as well as low-toxic materials and processes (for example, use rutile-type coated electrodes, replace welding with coated electrodes for mechanized welding carbon dioxide etc.).

2. When welding and cutting small and medium-sized products at permanent places in workshops or workshops (in cabins), it is necessary to use local ventilation with fixed side and bottom suction (welder table). When welding and cutting products at fixed places in workshops or workshops, local ventilation with an intake funnel mounted on a flexible hose must be used.

Ventilation should be performed by supply and exhaust with the supply of fresh air to the welding areas and its heating in cold weather.

When working in closed and semi-closed spaces (tanks, tanks, pipes, compartments of sheet structures, etc.), it is necessary to use local suction on a flexible hose to extract harmful substances directly from the place of welding (cutting) or provide general ventilation. If it is impossible to carry out local or general ventilation, clean air is forcibly supplied to the breathing zone of the worker in the amount of (1.7-2.2) 10-3 m3 per 1 s, using a mask or helmet of a special design for this purpose.

LITERATURE

1. Kurkin S. A., Nikolaev G. A. Welded structures. - M.: Higher school, 1991. - 398s.

Belokon V.M. Production of welded structures. - Mogilev, 1998. - 139s.

Blinov A.N., Lyalin K.V. Welded structures - M .: - "Stroyizdat", 1990. - 352s

Maslov B.G. Vybornov A.P. production of welded structures -M: Publishing Center "Academy", 2010. - 288 p.

Similar works to - Manufacturing technology of the fan casing

Materials used in the manufacture of air ducts, basic technological processes and types of machines required for the implementation of this production cycle.

1. The dependence of the thickness of the walls of the duct on the area of ​​its section.

2. The main types of machines required for the manufacture of steel galvanized air ducts.
The guillotine.
· Bending machine.
· Folding machine.
· Falseosadochny machine.
· Stiffening rib machine.
· Puklevochny machine.
ZIG machine.
· The device for production of works on spot welding.
· Spiral winding machine.
· The machine for production of branches of round section Gariloker (GORELOCKER).
· Rolling machine.

1. Materials used for the manufacture of galvanized steel air ducts.

Air ducts made of galvanized steel are mainly made from a sheet with a thickness of 0.5 - 1.2 mm, depending on their standard sizes, for example:
a rectangular air duct, ranging from 100x100 mm to 500x200 mm, is made of 0.5 mm thick galvanized steel sheet;
a rectangular air duct, ranging from 500x300 mm to 800x200 mm, is made of 0.7 mm thick galvanized steel sheet;
Rectangular air duct, from 800x300 mm up to 1000x1500 mm, is made of 1.2 mm thick galvanized steel sheet.

Used steel grade ST-3, ST-6.

2. The main types of machines required for the manufacture of steel galvanized air ducts:

Each machine is designed to perform one unique or several related technological operations for processing galvanized steel sheet, gradually turning it into a semi-finished product, a set of fittings and, finally, an air line ready for operation, consisting of a system of air ducts and ventilation equipment.

Guillotine.

The machine is designed to cut the steel sheet across the entire width of the roll and for nothing else. Structurally, it is a workbench on which a knife with a counterweight or an electric drive is mounted.

Bending machine.

The machine is intended for bending a steel sheet to the required angle (from 00 to 3600). Structurally, it is a bed with two guides, movable and fixed. The movable guide bends the sheet. The drive can be manual or electric.

Folding machine.

It is intended for the production of several types of locks connecting the edges of a steel sheet, and, accordingly, for connecting different sections of straight-seam air ducts: single lock, double lock. Structurally, it is a frame with a rolling mechanism and an electric motor.

Folding machine.

This device is designed to tighten (settle) the corner at the junction of the extreme edges of two steel sheets, that is, to close the lock and obtain a tight connection between two adjacent sections of a straight-seam duct to each other.

Rib machine.

It is intended for the manufacture of stiffeners that serve to reduce the vibration of the duct walls during the passage of air and, accordingly, reduce noise. Air ducts, the walls of which are equipped with stiffeners, do not rattle during operation and “keep their shape” better.

Punch machine.

Serves for processing of places of connection of an air duct with a flange and giving them the necessary rigidity, durability and tightness. In fact, the machine presses through the sheets of the flange and air duct, ensuring the strength and immobility of their connection to each other.

ZIG machine.

Designed for the manufacture of the correct angles on the edges of the sheets at the points of attachment to the sections of the air ducts of the following fittings made of galvanized steel sheet: bends, half-bends, reductions and tie-ins. In fact, the machine performs flanging and preloading of the edges of parts previously cut from galvanized steel sheet on other types of machines, GORELOCKER, for example.

Apparatus for the production of work on spot welding.

Carries out welding operations for joining sheets of steel by spot welding. It is used for the manufacture of section transitions of galvanized steel air ducts, mixing and distribution chambers of central and duct air conditioners, silencer sections and adapters.

Spiral winding machine.

It is applied by production of air ducts of exclusively round section. The thickness of the steel sheet used for the manufacture of spirally wound air ducts directly depends on the cross-sectional area of ​​the air duct - the larger the area, the thicker the sheet.

The air duct of circular section, starting from a diameter of 100 mm, and up to a diameter of 500 mm, is made of galvanized steel sheet with a thickness of 0.5 mm;
circular air duct, starting from a diameter of 500 mm, and up to a diameter of 900 mm is made of 0.7 mm thick galvanized steel sheet;
Circular air duct, from 900 mm in diameter up to 1250 mm in diameter, is made of 1 mm thick galvanized steel sheet.

The maximum allowable cross-sectional area of ​​​​the air duct that this machine is able to digest is 1.13 m2, with a diameter of 1250 mm.

Gariloker (GORELOCKER).

The machine of this type is designed for cutting galvanized steel sheet into segments, and further manufacturing bends and half-bends with a diameter of 100 mm to 1250 mm inclusive.

rolling machine.

This device is designed for the production of round straight-seam air ducts. Allows to make shaped products and inserts from 50 mm long. up to 1250 mm. inclusive: adapters and section transitions (from rectangular to round, and vice versa). It is also possible to manufacture a straight section of the duct, however, its length will be limited to 1250 mm.

The machine park listed above is used in the production of galvanized steel air ducts and fittings of the following types:
- Straight-seam galvanized steel air ducts of square section with a length of 10 cm to 2.5 m inclusive;
- Straight-seam galvanized steel air ducts of circular cross section from 5 cm to 1.25 m long inclusive;
- Spiral-wound galvanized steel air ducts with a length of 50 cm to 5 m inclusive.
- Section transitions (designed to connect air ducts of various diameters and section shapes).
- Elbows (Designed to rotate the duct by 900, can be either round or square).
- Semi-bends (Designed to rotate the duct by 450, can be either round or square).
- Tees (Intended for dividing the air duct line into two parts of the same section, in a non-standard version it is possible to divide it into equal parts with a transition to a larger section, for example (100x100 / 100x100) / 200x100).
- Adapters (Designed for attaching gratings of both ceiling and wall types. A non-standard part that requires the development of an individual drawing. Structurally, the adapter is a steel box with an inset on top or side).

Reduction (A shaped part designed to switch from a main pipe to an air duct of a smaller diameter. Reductions of both rectangular and round sections are used. Structurally, they are divided into straight tie-ins and saddle tie-ins. The length of the tie-in cannot be more than 20 cm).

Reminder: You can wholesale components and spare parts for industrial ventilation systems from us: fastening of air ducts, air conditioners, rectangular and round air ducts, traverse, mounting rail, galvanized corners, bracket for connecting flanges, mounting tape, perforated, tape clamp, aluminum tape, brackets, gratings and anemostats, sheet and roll insulation, galvanized metal sheets. We also produce wholesale trade fasteners: threaded studs, self-tapping screws, screws, bolts, screws, nuts, washers, rivets, drive-in anchors. Deliveries go throughout Russia, from a warehouse in Moscow.

Good day!

Not a single residential, office, retail, industrial or warehouse space today. And air ducts made of galvanized steel deservedly occupy a leading position among various ventilation ducts. About what this popularity is due to and how not to get lost in the variety of the presented assortment, we will tell in the next material.

Galvanized air ducts - the most common type ventilation pipes. Which is easily explained.

Advantages of galvanizing:

• Light weight, due to which the installed structures create insignificant loads on the buildings. In addition, the lightness of the material facilitates the process of delivery to the installation site and engineering work.
• The flexibility of the material makes it possible to give the air duct elements any shape, which not only expands their range, but also improves the aerodynamic characteristics of the line.
• Strength and resistance to open fire and aggressive environments. This significantly expands the scope of use and increases the service life of ventilation pipes made of thin-sheet galvanized steel from 10 years or more.
• Low cost.

Galvanized ventilation ducts are easy to maintain. They do not require preliminary priming, since the metal is not subject to an active corrosion process. Aesthetic appeal allows them not to be painted.

The disadvantages of galvanized steel include:

• Increased noise level, characteristic of any metal structure. However, this problem can be solved either by a well-thought-out wiring scheme that minimizes the number of bends and transitions, or soundproofing.
• Tendency to form and accumulate condensate. As a solution - insulation of the pipeline.
• Susceptibility to deformation as a result of a powerful mechanical impact caused by a strong impact, displacement or fall of the structure. Under normal operating conditions, such difficulties do not arise.

The combination of quality, cost of material and a variety of technologies that minimize the disadvantages make galvanized pipelines the most popular types of air ducts used in the arrangement of ventilation mains.

Types of galvanized air ducts

The variety of galvanized air ducts is due to a number of specifications given to products during the manufacturing process. So the following types of products are distinguished:

1. Cross-sectional shape: rectangular or round.
2. By type of seam: welded and folded.
3. In the direction of the seam: spiral wound and straight seam.

Rectangular and round

	Round steel duct	Rectangular steel duct
Aerodynamics	Uniform air distribution and, as a result, improved aerodynamics.	High aerodynamic drag
Air mass movement speed	High.	Low. For large circuit sizes, forced air circulation is required.
Noise figure	Good noise-absorbing properties due to the absence of turbulence effect.	Requires good soundproofing.
care requirements	The high air velocity prevents dirt and dust particles from settling in the pipeline.	Requires periodic cleaning of the pipeline.
Estimated data	The shape of the section makes it difficult to calculate data on the area of ​​the structure.	The rectangular configuration makes calculations easier.
Mounting	Products are lighter and do not require reinforced fasteners. Save time and low labor costs.	The severity of the structure requires the arrangement of reliable clamps.
Price	Cheaper by an average of 30%. Minimum costs for transportation, storage, installation and thermal insulation.	In view of the high aesthetics, there are no costs for masking and decorating the highway.

The advantage of rectangular air ducts lies in the configuration and variety model range, which allows you to adapt the ventilation circuit to the characteristics of any room without compromising the calculated cross-sectional area, playing with the width and height of the pipe.

Straight seam and spiral wound

Longitudinal welded pipes are made by bending a sheet of galvanized steel into a round or rectangular pipe. This technology reduces the cost of products, but it also limits its length, which increases the number of connecting elements of the pipeline.

Spiral-wound (spiral-lock or spiral-welded) air ducts are twisted from a thin metal tape. In this case, the seam goes in a spiral and plays the role of a stiffener, which increases the strength of the pipe, and when using the welding method, ensures its tightness.

Spiral-wound air ducts are characterized by:

• less weight;
• increased tightness;
• a small number of butt elements;
• increased speed of movement of the air mass, tk. the spiral shape creates additional rotation in a closed loop;
• reduced noise level.

However, the ribbed surface provokes the accumulation of dust inside the pipeline.

Tightness and density

Tightness and pressure are indicators that ultimately determine the efficiency and cost of the ventilation circuit. A leaky line reduces the quality of air exchange and entails an unreasonable increase in the capacity of pumping equipment, an increase in energy costs, and also leads to the accumulation of condensate inside the pipes.

There are 3 classes of tightness of air ducts:

1. A (low). Air permeability from 1.35 to 0.45 l/sec/m².
2. B (medium). Air permeability from 0.45 to 0.15 l/sec/m².
3. C (high). Air permeability less than 0.15 l/sec/m².

By the coefficient of internal pressure (density) distinguish:

• H-models (normal pressure). Designed for ventilation and smoke removal systems of objects belonging to the category of fire hazard class "B" and "G". Do not require strong sealing, tk. allow a certain percentage of leakage. Rubber seals are usually used as a sealant.
• P-models (dense). They are installed at facilities equipped with powerful pumping equipment and classified as fire and explosion hazardous. They are characterized by 100% tightness of seam joints and the presence of a hermetic lock at the junction of the elements with each other.

What is better and where is it used?

The protective layer of zinc resists the damaging effects of open air, moisture and ultraviolet radiation. Therefore, galvanized ventilation ducts are actively used both indoors and outdoors for arranging systems:

1. natural and forced ventilation,
2. conditioning;
3. aspiration (removal of small particles contained in the air);
4. smoke removal (removal of combustion products);
5. removal of exhaust gases;
6. transportation of gas mixtures, purifiers and air humidifiers.

Even the organization of a conventional hood in the kitchen is most often carried out by means of steel ducts.

When deciding on the use of one or another type of air duct, one should be guided by the features of the operation of the future design:

• Rectangular air ducts are used to save space in small predominantly residential or service premises (private houses, apartments or offices).
• For aspiration and transportation of harmful gases, round pipes with a welded seam are suitable, providing top speed air movement and complete tightness of the case.
• In industry, preference is given to round shapes, characterized by most efficient and minimum cost.

Elements of the ventilation system

The ventilation line is always a complex structure, consisting of numerous elements that allow:

1. change the direction of the contour depending on the configuration of the premises;
2. bypass ledges;
3. connect several circuits into a single network.

Branches and boxes

The main elements of the duct that determine its direction are ducts and bends. The former pave the path in a straight line, the latter change the contour geometry at an angle of 15⁰, 30⁰, 45⁰, 60⁰ or 90⁰.

Other shaped elements

Ventilation is a complex and extensive network of channels, which is problematic to mount without the appropriate elements. Such components are usually called shaped products.

These include:

• Adapters connecting circuits of various diameters to each other - confusers and diffusers. The first narrow the highway, the second expand.
• Tees and collar tie-ins, ensuring the adjoining of two mains to each other.
• Crosses used to cross two perpendicular air currents.
• S-shaped adapters (ducks) connecting two circuits that do not match in axis and / or section.
• Round nipples and couplings connecting two round boxes. The first are inserted inside, the second are put on over the pipes.
• Plugs installed at the ends of the circuit.
• The umbrella is roof, preventing hit of an atmospheric precipitation in a ventilating shaft.
• Supply and exhaust grilles and other shaped parts.

Dimensions

GOST

1. GOST 14918-80 - air ducts made from steel sheet with a thickness of 0.5 to 1 mm by rolling and designed to transport air with a humidity of not more than 60% and a temperature of less than 80⁰C.
2. GOST 5632-72 - air ducts characterized by a high degree tightness, corrosion resistance and high temperatures(about 500⁰C) and designed to move hot air and chemical gases.

Size Chart Weights and Diameters

Production of galvanized air ducts

Galvanized air ducts are manufactured on special metal-working equipment from thin-sheet cold-rolled steel in accordance with established by the state standards (SNIP 41-01-2003 and TU 4863-001-75263987-2006). The cutting of metal takes place in automatic mode according to the parameters set by the program.

• Circular sections are processed by rollers, which give the workpiece the required diameter, followed by rolling the longitudinal edge on a seam-rolling machine.
• Spiral-wound ones are made using a different technology: steel with a width of 137 mm is twisted in a spiral with a seam inward.

The use of high-quality galvanizing prevents the galvanized coating from peeling off the metal at the bending points of the product.

Technological standards prescribe for each type of section to use metal of a certain sheet thickness:

Average cost and where to buy

The cost of air ducts made of galvanized steel depends on the size of its cross section and the thickness of the metal. The price is calculated for 1 m². On average, the cost of 1 m² of a product on the market is about 320 rubles. Installation work will cost an average of 700 rubles. for the same square metre.

Despite the wide representation of air ducts in online stores, it is still worth buying them directly from the manufacturer, who is able to accompany each product with a quality certificate.

How to choose?

The operation of the air exhaust system (SVO) depends on how correctly the area of ​​\u200b\u200bits section is calculated.

S - Sectional area.

P - CBO performance.

v - The speed of movement of the air mass (for residential premises, an indicator of 3-4 m / s is used).

Determination of ventilation performance involves determining the amount of air required for a comfortable stay in the room. It is calculated in 2 ways:

• Air volume required:

P - CBO performance.

A - The number of people in the room during the hour.

n - Air consumption rate according to SNIP 41-01-2003 and MGSN 3.01.01.

• By the frequency of ventilation (ventilation):

P - CBO performance.

V - The volume of the room (with equal data, the entire room)

k - The ventilation rate established by the standards of SNIP 41-01-2003.

shape and diameter

The quality of air exchange, energy efficiency and design of the room depend on the selected configuration and the size of the air duct section. Therefore, the choice of air channels should be approached in detail:

1. The smaller the diameter of the duct, the higher the speed of the air mass. It is important to be guided by the principle of the "golden mean", because the higher the speed, the higher the noise level.
2. Round air ducts provide faster air movement, are easier to install and are cheaper.
3. Rectangular are stronger and harmoniously fit into the design of any room.

Construction and rigidity

Depending on the specifics of the design application, there are:

• rigid, semi-rigid or flexible;
• standard or thermally insulated;
• fire retardant.

The tighter the seams, the stronger the connection and the longer the period of operation.

Material

Galvanized ventilation ducts are manufactured standard view and insulated.

1. The design of insulated models provides a special insulating layer of mineral fiber, polyurethane, foam elastomer, felt or other materials. They maintain the optimum air temperature inside the circuit, preventing the formation and freezing of condensate on the walls. In addition, they reduce the noise level.
2. Zinc coating can be one-sided or two-sided. Due to the formation of condensate inside the circuit, double-sided galvanizing is more practical, because. protects the contour from the internal corrosion process.

Not so long ago, galvanized aluminum ducts appeared on the market, the coating of which is 95% zinc and 5% aluminum. They are characterized by greater ductility and improved anti-corrosion properties.

Fastening

Ways of fixing the air ducts depend on the configuration:

• with a round section, coupling, bandage and nipple connection of elements are used;
• rectangular air ducts are fastened with latches and mounting brackets.

Sometimes welding is used.

Installation rules for galvanized ventilation

The laying of ventilation ducts from thin-sheet galvanized steel is carried out in stages.

The ventilation system is one of the integral parts of any premises - residential, industrial, warehouse, retail, office, etc. The internal microclimate, and, therefore, the level of comfort of a person staying there, depends on a well-equipped ventilation. That's why right choice and installation of the air duct - the basis of high-quality air exchange.

In this article, we will consider the main types and properties of these products, their advantages and disadvantages, as well as application features.

An air duct is one of the main elements of the ventilation system, the purpose of which is to redistribute air, providing both its inflow into the room and its exhaust from it. Ventilation, at the same time, can be both natural and forced - with the help of special devices.

Air ducts are used not only for ventilation, but also to ensure the circulation of air masses when:

• Air heating.
• Air conditioning.
• Transportation of air for technological purposes.

Depending on their purpose, a variety of materials for air ducts can be used - black or galvanized steel, aluminium foil, reinforced steel wire, polyester film, composite materials or plastic. The most popular in household use are precisely plastic ventilation ducts.

Advantages of plastic air ducts

A plastic ventilation duct is one of the most affordable and effective solutions for equipping a ventilation system in any type of premises. Most often, ventilation boxes are made from a type of plastic such as polyvinyl chloride. It has a number of positive aspects, which leads to many reasons to use this particular type of ventilation duct.

The ventilation duct made of polyvinyl chloride has its main advantages:

• mechanical strength.
• Environmental safety.
• elasticity.
• Resistant to chemically active and organic liquids.
• Resistant to temperature fluctuations.
• Low specific weight.
• Possibility of acquiring the desired form.
• Ease of installation.
• Ease of maintenance.
• Wide range of colors.
• Variety of shapes and sizes.
• Affordable prices.
• Possibility of dismantling for cleaning or repair work.