Flexible air ducts for application: features and ventilation. Features of the use and installation of flexible air ducts Application of air ducts

1. Check oral cavity the victim for foreign bodies.

2. Determine the size of the air duct using the distance from the victim’s earlobe to the corner of the mouth.

3. Take the air duct into right hand so that its bend looks downwards towards the victim’s tongue, and the air duct opening looks up.

4. Insert the air duct into the victim’s mouth approximately half its length, then turn 180° and push forward until the flanged end rests against the victim’s lips. -

Rice. 1. Insertion of the oropharyngeal airway

For ventricular fibrillation and immediate defibrillation is not possible:

Precordial beat,

If there is no effect, continue cardiopulmonary resuscitation, ensure the possibility of defibrillation as quickly as possible,

Adrenaline - 0.1%, 0.5-1.0 ml intravenously every 3-5 minutes of cardiopulmonary resuscitation.

As early as possible - defibrillation 200 J:

If there is no effect - defibrillation 300 J,

If there is no effect - defibrillation 360 J,

Lidocaine - defibrillation 360 J,

If there is no effect, after 3-5 minutes repeat the injection of lidoczna at the same dose - defibrillation 360 J,

In the absence of affect - ornid 5 mg/kg - defibrillation 360 J, v

If there is no effect, after 5 minutes repeat the injection of Ornid at a dose of 10 mg/kg - defibrillation 360 J,

In the absence of the effect of novocaine MIA - 1 g (up to 17 mg/kg) - defibrillation 360 J,

If there is no effect - magnesium sulfate - 25% 10.0 ml intravenously - defibrillation 360 J,

If there is no effect, atropine 0.1% 1.0 ml 3-5 minutes before the onset of effect or a total dose of 0.04 mg/kg.

Perform pacing as soon as possible.

Eufillin 2.4% 10.0 ml intravenously.

Hospitalize after possible stabilization of the condition.

Cardiopulmonary resuscitation can be stopped if heartbeat and breathing are restored or if signs of biological death occur.

Algorithm for basic cardiopulmonary resuscitation (Fig. 2)

1. Place the victim in a horizontal position on his back on a solid base.

2. Free your neck, chest and waist from restrictive clothing.

3. Examine the oral cavity and, if necessary, carry out mechanical cleaning, after turning your head to the side.

4. Throw back the victim’s head and fix it in an extended position with the hand on the victim’s forehead.

5. Pull the victim’s lower jaw forward with the middle and index fingers other hand.



6. Pinch the victim’s nose with the thumb and index finger of the hand on his forehead.

7. Make 2 test injections.

8. Check the pulse in the carotid artery; if there is no pulse, then

9. Make 2 precordial beats.

10. Check the pulse in the carotid artery; if there is no pulse, then

11. Start chest compressions and artificial ventilation.

12. Monitor efficiency every 2 minutes:

If there is no effect, continue the activity, making 15 pressures on the sternum for about 10 s and 2 insufflations lasting 1.5-2 s each;

If independent breathing movements and a pulse appear in the carotid artery, place the victim in a stable lateral (recovery) position.

If damage to the cervical spine is suspected, turning the head to the side and throwing it back is strictly prohibited!

ANGINA

One of the main manifestations coronary disease heart - angina pectoris.

Literally, “angina” means pain behind the sternum, angina pectoris.

Angina pectoris can manifest itself in several clinical forms. The most common type of angina is exertional angina; every year it occurs in 0.6% of the population.

IN age group of the population from 45 to 55 years old, it occurs in 5% of cases in men, and in about 1% of cases in women. Due to the decrease in the protective effect of estrogens during menopause, women over 65 years of age have approximately the same incidence of cases as men.

Classification:

A. Angina pectoris is stable.

B. Angina pectoris is unstable.

A. Stable exertional angina is divided into 4 functional classes:

1 class. Heart pain occurs during extreme physical or mental stress.

2nd grade. Pain in the heart begins when you rise to about D0* floor or when brisk walking two blocks away



3rd grade. Pain occurs with less load. Approximately walking briskly for a distance of about one block or quickly climbing one floor.

4th grade. Pain regularly occurs during normal physical activity.

In Unstable angina is divided into:

New-onset angina (when the attack occurred for the first time or recurred within the first month);

Progressive (when the number of attacks has increased over time) Lately or the duration of the attack has increased, or the number of nitroglycerin tablets to relieve an attack of angina has increased);

Special, variant, Prnntzmetal's angina, which occurs spontaneously at certain hours of the night. This form of angina is characterized by a series of attacks with an interval of 10-15 minutes.

ETIOLOGY

In most cases, angina occurs due to atherosclerosis of the coronary vessels. As a result of the discrepancy between the myocardial need for oxygen and its delivery through the coronary vessels, which developed as a result of atherosclerotic narrowing of the lumen of the arteries, myocardial ischemia occurs, which is clinically manifested by chest pain. As a result of ischemia, disturbances in the contractile function of a portion of the heart muscle develop.

All types of air ducts are divided into rigid, semi-rigid and flexible, each of which has a number of advantages and disadvantages, and is also focused on a specific area of ​​application.

Any ventilation system with forced air movement is subject to vibration loads from operating fans. To reduce vibrations and noise, experts recommend integrating silencers into the ventilation network: tubular, cylindrical, channel, chamber or plate. This isolates the main source of noise, but there are also secondary ones - any element of the ventilation network that changes the configuration of the air duct. Such elements include adapters, elbows, tees, “cleats” and other shaped products.

Recently, corrugated flexible and semi-rigid air ducts, which have fairly high sound and vibration absorption, are increasingly being used instead of transitional and shaped parts. The use of such hoses makes it possible to eliminate most of the auxiliary shaped parts during installation due to the flexibility of the design.

Currently, the ventilation market is able to offer the consumer a lot of flexible and semi-rigid ventilation ducts from various polymer and synthetic materials, however, they continue to be in greatest demand aluminum structures. In this case, a flexible or corrugated air duct can be framed or frameless.

Flexible and semi-rigid ventilation ducts are manufactured in a wide range of diameters. The average operating temperature range for aluminum-polymer combinations is -30°C to +120°C. Depending on the materials, the diameter of the wire forming the frame, and the pitch of the spiral, semi-rigid ventilation hoses can be designed for pressures up to 2500 Pa.

Flexible frameless ventilation sleeves

Flexible corrugated air duct without reinforcement (frameless)Flexible aluminum air ducts are mainly used in ventilation systems with low air pressure. The basis of the frameless air hose is foamed polyethylene, the surfaces of which (both external and internal) are covered with aluminum film. Such flexible aluminum air ducts can be used in ventilation systems for smooth turns of the main line, as short straight sections of the network, and also as shaped elements, for example, tees.

Semi-rigid ventilation sleeves with metal spiral frame

Semi-rigid sound-absorbing frame air ducts have a metal spiral as a base, onto which three layers are applied: outer and inner - made of aluminum foil, the middle one is made of mineral fiber, which is both a sound and heat insulator. The thickness of the insulation varies between 25-50 mm. Inner layer may have microperforation. Outer layer- continuous sealed, therefore one of the names of such a sleeve is an insulated air duct. The semi-rigid frame air duct, not intended for sound insulation, is made of a single layer of foil.

Requirements for air ducts during installation:

Flexible and semi-rigid ventilation hoses must be installed in a fully stretched state, otherwise the aerodynamic resistance in the network will increase sharply;
- the ventilation hose must be fixed to stationary cross-beams or hangers with a pitch of no more than 1.5 m;
- sagging of the air duct hose between adjacent support points - 50 mm maximum;
- excess air duct along the length of the main is not allowed;
- the angle of rotation on the flexible section should not be less than the bore diameter of the hose itself;
- the aluminum shell can accumulate static electricity from the air, so such hoses should be grounded.

Whatever material is used for air ducts, the inner surface of the channel has micro-irregularities - roughness. Moreover, the higher the roughness (the worse the surface cleanliness), the higher the aerodynamic losses, and, as a consequence, increased noise generation. By virtue of design features The roughness of the inner surface of flexible hoses is in any case worse than that of rigid ventilation ducts. Therefore, the use of flexible air ducts on long straight sections of the ventilation main is extremely undesirable.

Rigid spiral-wound air ducts

If the ventilation line is long, then to reduce aerodynamic losses it is necessary to use rigid ventilation ducts made of thin sheet metal, which in turn are divided into straight-seam and spiral-wound ones.

Straight-seam metal air ducts can be round, oval, rectangular and square sections, while spiral-wound ones are only round. Spiral-wound air ducts with round have better aerodynamic characteristics, are cheaper to manufacture and are more technologically advanced to install.

Winding air ducts are manufactured at specialized equipment made of galvanized or galvanized strip steel, as well as aluminum using the spiral winding method. This technology allows the production of ventilation ducts in the range of bore diameters from 100 mm to 1600 mm. Metal thickness - from 0.55 to 1.4 mm. Standard length finished product– from 3 to 4 meters.

Regulatory and technical documentation regulates the following classes of air ducts: “P” - dense, “N” - normal. Round spiral air ducts belong to class “P”, and with the use of special sealants when installing the ventilation network, they can achieve almost complete sealing of the system. Air ducts of class “P” are used if the static pressure of the fan in the network is 1400 Pa or more.

Ventilation systems with air ducts of a spiral-wound design involve the installation of a main line using various shaped parts: bends for different angles, tees and transitions, crosses and plugs, valves, etc.

Flexible air ducts, with certain reservations, are effectively used in industry, administrative, public buildings. In residential buildings, this type of air ducts is only gaining popularity in Russia. Manufacturers offer a variety of operational characteristics, physical properties flexible air ducts made of plastic and metal.

A flexible air duct is a soft pipe reinforced with a metal spiral. The operation of such channels differs from rigid systems in a number of features. However, the installation of flexible ventilation ducts is simpler and cheaper than assembling communications from rigid pipes, since it does not require fittings for turning corners.

Advantages of flexible air ducts:

  • ease of installation;
  • light weight;
  • the ability to easily change the direction and configuration of the laid channel;
  • affordable price;
  • the presence of heat, vibration and noise insulation from the manufacturer;
  • compatible with all types of pipes.

Disadvantages include:

  • poor resistance to mechanical damage during transportation and installation;
  • restrictions on use;
  • the need for professional knowledge during installation.

Note! The main advantage of flexible air ducts is the significant simplification of installation of ventilation systems in conditions of limited space and the need to go around many obstacles.

Scope of application

Manufacturers produce flexible pipes for air channels in the diameter range from 76 to 710 mm. There are air ducts for general ventilation and high-temperature ones.

IN housing construction Pipes up to 350 mm in diameter are in demand. As a complete ventilation system, they are installed in low-rise residential buildings. As separate hoses connected to a central shaft, flexible air ducts are indispensable in multi-apartment buildings.

Flexible air ducts are used:

  • in air conditioning systems;
  • in the oil refining and chemical industries;
  • in public buildings;
  • in the food industry.

IN production workshops flexible air ducts use:

  • for removing waste, dirty air, which contains mechanical suspensions and chemical contaminants;
  • for pumping warm air.

In this article we will tell you what flexible air ducts for ventilation are, how and what they are made of and what are the features of their use. The topic of the article is of great interest, because, in addition to exploitation in industrial systems, flexible ventilation ducts are used when installing household hoods in kitchens.

Not paying attention to what is on sale a large assortment solid round and rectangular channels, the need to use flexible pipes does not become less urgent. The reason for its popularity is that it is impossible to install a solid channel on some inconvenient surface areas.

Again, on some surfaces with a huge number of protruding areas, it is simply unprofitable to install a solid structure with a huge number of joints. The use of multiple taps can replace the acquisition flexible pipe, which is different high degree operational reliability and tightness.

Main varieties


On this moment Flexible iron and plastic air ducts for ventilation are produced. Both categories of products are used in the arrangement household systems exhaust ventilation. Let's take a closer look at the features of these types of devices.

Plastic channels are made from the following types of polymer materials:

  • Polyvinyl chloride (PVC) with metal spiral reinforcement is used to make air ducts with a fairly smooth inner surface.

Flexible PVC channels are manufactured by extrusion using fully automated equipment, and therefore the price of the finished product is quite low.

PVC channels are not abrasion resistant, but at the same time they are completely transparent, and therefore are optimal choice for the installation of hoods in the woodworking industry. The diameter of PVC products is limited to the size range of 16-200 mm.

Fundamentally important: A significant drawback of air ducts made of polyvinyl chloride is their low resistance to low temperatures, based on this, they cannot be used in supply systems, combined with heating. Moreover, when the temperature drops below +5°C, such products lose their former flexibility and become brittle.

  • Viniurethane with metal spiral reinforcement is used for the production of air ducts on the principle of welding a polymer tape together with an iron spiral.

The advantage of such air ducts is their high resistance to mechanical deformation and very low noise level. This type ventilation ducts are characterized by enormous flexibility. For example, a product can be tied into a knot without compromising its integrity.

Due to their great strength and variety of standard sizes, these flexible air ducts can be used both for the construction of ventilation and for connecting air conditioning systems.

  • Air ducts made of polyolefin or polyurethane (PU) with metal spiral reinforcement demonstrate average strength. The products can be used in the installation of household hoods. A significant drawback of such products is the low aerodynamics of the ribbed inner surface.

Fundamentally important: Due to the lack of smoothness of the internal walls, air ducts made using these materials are more susceptible to blockages than analogues with a smooth internal surface.

Metal products are presented in the following categories:

  • Metal air ducts for ventilation are made from thin sheet steel, cut into strips. The tape is shaped into a spiral, after which a solid pipe is produced from the blank.

Such structures are distinguished by their enormous weight and great strength. For greater durability, steel before starting production work galvanized.

  • Aluminum air ducts for ventilation In addition, they are made of iron strip, from which a round pipe is formed. The resulting ribs are connected to each other with a seam lock.

Such products will be able to bend almost at right angles without compromising the tightness. Moreover, aluminum products, as well as their metal counterparts, are effectively used in the temperature range from -30°C to +300°C.

Fundamentally important: Flexible iron ducts are not The best decision for reusable use. If the ventilation duct is installed and takes the desired shape, then it must not be straightened.

Operation of flexible ventilation ducts


In accordance with TU 36 736 93 for ventilation iron air ducts, these products are used in various industrial fields, in the arrangement of construction projects for residential and public purposes, etc.

The latest technologies make it possible to make such pipes not only flexible, but also truly airtight. Despite the increased functionality and demand, the price of flexible air ducts is not much higher than the cost of their solid counterparts.

A critical condition for ensuring the efficient operation of these products is the correctness of installation work. Moreover, the efficient operation of air ducts can be ensured by promptly cleaning the internal cavity from blockages.

Let's look at the features of installing flexible channels.

Features of installation work

When connecting iron air ducts for ventilation at turns, for the purpose of optimal tension, use iron solid elbows with the ability to adjust the angle of rotation. The knee is firmly attached to load-bearing structures and due to this, it becomes possible to provide the required air duct tension on indirect sections of the line.

This installation development provides the following advantages:

  • Reduced resistance to the inner surface of the air duct due to the fact that the inner sleeve is properly tensioned.
  • Possibility of adjusting the bend angle in the range of 90-180 degrees;
  • Maintaining the required degree of mobility of the ventilation duct during system operation.
  • Reliable fastening of the flexible air duct at turns.
  • Low possibility of bending of the flexible ventilation duct on rotating sections.

Fundamentally important: The use of flexible air ducts is subject to a series of restrictions, including the inadmissibility of installation in vertical risers, the height of which is more than 6 meters. In addition, flexible channels do not need to be used without taking into account such parameters as heat resistance, design features, etc.


The installation instructions assume compliance with the following requirements:

  • Getting started installation work You need to fully stretch the inner sleeve of the air duct with your own hands to eliminate pressure losses and bends.
  • Excess flexible pipe is cut off. No need to mount ventilation system, leaving additional length of the air duct in reserve.
  • Hanging brackets are selected taking into account a sufficient width at which outside diameter the jacket (shell) will not change its shape.
  • To pass wall structures We make sure to use iron sleeves or adapters, which will ensure the safety of the flexible air duct during installation and subsequent operation.

Installation work is carried out as follows:

  • We cut flexible temperature-resistant air ducts for ventilation in a stretched state with metal scissors, while the spiral part is cut with wire cutters. When working with plastic channels, the polymer shell is cut with a sharp knife, while the spiral is cut off with wire cutters.
  • The connection is made using a nipple-type coupling, aluminum self-adhesive tape or mastic. The entry of the air duct into the pipe must be at least 50 mm
  • For additional strength, we fix the connection with a nylon or iron tie.
  • Installation of semi-rigid air ducts is carried out by connecting to flanges and fixing with screws.
  • At the end of the work, we check the tightness of the connections.

Conclusion

Now you understand what PVC air ducts for ventilation and their iron analogues are. As a result, you will be able to select those modifications of ventilation ducts that will meet the needs of the air exchange scheme used.

You can find more necessary and educational information by watching the video in this article.

By cross-sectional shape Air ducts are rectangular, square and round. They are made from straight and shaped components. The sizes and types of air ducts are established in departmental building codes(VSN) 353-86 “Design and application of air ducts from standardized parts”, TU 36-736-93 “Metal ventilation ducts”, SNiP 2.04.05-91 “Heating, ventilation systems, air conditioning”.

By manufacturing method air ducts are distinguished: o seam - connected by seam seams (Fig. 6.25). The thickness of the metal for seam air ducts should not exceed 2 mm for aluminum, 1 mm for corrosion-resistant steel;

o welded - connected by an overlap weld, the thickness of the metal with this type of connection is in the range of 1-3 mm.

Round air ducts are produced in diameters 100, 110, 125, 140, 160, 180, 200, 225, 250, 280, 315, 355, 400, 450, 500, 560, 630, 710, 800, 900, 1000, 1120, 1250, 1400, 1600, 1800 and 2000 mm.

For rectangular air ducts, all values ​​of the specified dimensions are used, but it is advisable to adhere to the following values: 100,150,200,250,300,400,500,600,800,1000,1250,1600,2000 mm.

The connection of individual parts of round air ducts to each other is carried out using flanging bands for air duct diameters up to 800 mm and using angle steel flanges for large diameters. Rectangular air ducts with a side less than 1600 mm are connected on profiled tires using four bolts at the corners and additional latches if the side is more than 1600 mm.

By material, from which they are made, air ducts are divided into the following groups:

o seam air ducts made of thin-sheet galvanized steel 1 mm thick (without painting); o seam air ducts made of thin-sheet black steel 1 mm thick, followed by painting inside and outside with GF-021 primer;

Rice. 6.25. Sequence of operations for manufacturing seam connections of air ducts: A- single fold; 6 - single fold with clamp

o welded air ducts made of thin sheet steel with a thickness of 1.2-3.0 mm, followed by painting with GF-021 primer; o seam and welded air ducts made of corrosion-resistant steel (usually grade X18N9T) with a thickness of 0.5 to 3 without painting;

o seam air ducts made of titanium (p = 4500 kg/m 3), which have the highest corrosion resistance and are used to move aggressive media; o seam air ducts made of metal-plastic, clad on one or both sides with PVC or PVC film. With one-sided coating, the film is placed inside the air duct with an aggressive environment.

For conventional general exchange systems, seam air ducts made of galvanized steel are usually installed. Welded air ducts are used for increased density requirements (smoke exhaust shafts, air ducts passing through rooms with explosion hazard categories A and B) and when moving air with a temperature above 80 °C.

Flexible fabric (reinforced) air ducts, which have become widespread in last years, allow you to avoid complex adjustments at the point of connection from the lines to the air distributors and grilles.

There are the following types of fabric air ducts: o airtight fabric ducts made of 100% polyester - air is supplied to the room through the entire surface of the air ducts;

o airtight fabric channels with perforations - injectors - air is supplied to the room through special holes in the air duct material.

The speed of the air flow through the airtight material does not exceed 0.01-0.5 m/s, the speed of the air leaving the cracks is 4-10 m/s, through the perforated holes (injectors) 7-13 m/s.

The ducts are inflated by a flow of air and distribute it evenly along the length of the duct. They have significant noise absorption capacity and trap all dust particles larger than 5 microns. They can be used in rooms with a high air exchange rate, without creating local areas with increased air mobility. Such air ducts can be easily dismantled, washed or cleaned.

They are made: cylindrical in shape (for intensive air exchange without drafts), semicircular in shape (for rooms with low ceilings), the size of a quarter of the section of a circle (installed around the perimeter of the room) with a diameter of 100 to 1000 mm and a length of up to 100 m, various densities, allowing you to change the air supply from 160 to 500 m 3 / h at a static pressure inside the air duct of 100 Pa.

Fabric ducts can be installed in one work shift. Sections of air ducts (5 m long) are joined together using zippers. Air ducts are suspended using tensioned cables or slats. In the latter case, the fastening of the air ducts is more rigid and the air duct retains its shape without air supply.