Manufacturing of a round exhaust hood. What types of umbrellas are there for a chimney or ventilation pipe, and how to make them yourself. Elongated faceted umbrella

A necessary element of any serious kitchen is an exhaust hood. Such a device is required to be installed in industrial enterprises, but it also has a worthy place in domestic kitchens.

This hood option is exceptionally effective at removing cooking-related contaminants from the air. Let's look together at the features of how this works. exhaust equipment and points that you need to pay attention to when choosing a hood for the kitchen.

A device of this type is a powerful hood designed to effectively ventilate air in a kitchen area. They are most often installed directly above cooking surfaces in restaurants, cafes, canteens and other enterprises. Catering.

Such a device can be installed not only above conventional kitchen stoves, but also over other similar equipment: grill, oven, etc.

The quality of dishes will only benefit from the presence of a good hood. Umbrellas trap water vapor, particles of oil and fat, and remove odors emanating from prepared dishes. All these contaminants rise upward under the influence of hot air and enter the working cavity ventilation hood. Here, the polluted air passes through a filtration system, where the purification process takes place.

Exhaust umbrella – stylish and modern device which will provide effective cleaning air in a domestic or industrial kitchen

Then the air masses, freed from unnecessary inclusions, are returned to the kitchen area or removed through ventilation duct, depending on the type of device.

Fatty contaminants move through a separate channel and are collected in storage cups, from which they are periodically removed.

Grease traps are special aluminum elements that are installed inside exhaust hoods. They trap particles of fat and other relatively large contaminants

To facilitate the process of cleaning storage units from fat deposits, it is recommended to first pour a special detergent into the glasses that can effectively dissolve fat.

The advantages of umbrella-type exhaust structures include the following:

the ability to use remote control;
high degree of automation;
the ability to install a suitable model in almost any area of the kitchen;
a wide range of different models made from various materials with an attractive design;
high level of productivity.

Among the disadvantages of such equipment, the increased noise generation caused by the operation is primarily noted. powerful fan. For proper operation The unit should be serviced regularly, i.e. purchase and promptly replace carbon filters.

These items cannot be cleaned or refurbished and may cost more to operate than expected. Besides, good equipment This type is quite expensive in itself.

An island umbrella can be installed right in the middle of the kitchen if the size of the room allows it. IN small room such a device can be placed above a stove installed near a window

Exhaust hoods are always necessary in the kitchen. Particles of fat, hot steam, soot, drops and other contaminants may not be noticeable at first glance, but over time they form various surfaces a layer of dirt that is not easy to remove.

In addition, gas residues that can enter the kitchen air and the smell of accidentally burnt food are also not good for the health of others.

The design of the ventilation hood is a steel dome-shaped housing, inside of which there is a fan and a set of filtration elements. A special aluminum grille is designed to collect relatively large particles, which protects the ventilation turbine.

In catering establishments, powerful exhaust hoods are required for use over cooking surfaces. Similar devices are used to remove harmful fumes in other industrial plants.

An acrylic filter is usually used to remove a significant portion of grease contaminants. In installations with recirculation, it is mandatory to use a carbon filter, which provides fine air purification. The spark-extinguishing mesh protects the elements from overheating and possible fire.

It is especially necessary if the umbrella is installed above a device with an open flame. All filter elements must be periodically cleaned or replaced. Carbon filters are replaced as soon as they become dirty; these elements cannot be restored.

Some types of acrylic filters can be washed and reinstalled, but this treatment quickly causes them to lose their shape, so the number of cleaning and recycling cycles is limited.

The exhaust hood must be large enough to cover the parameters of the processed material. hob no less than 100 mm

A fan or ventilation turbine built into the umbrella ensures air circulation in the right direction with the required intensity. The performance of this element provides the total power of the hood, which should be correlated with the total volume of the room in which it will be installed.

Most umbrella hoods are equipped with lighting, which is very convenient. Such lamps can be used as additional lighting in the kitchen. Along with conventional incandescent lamps, halogen or diode lighting fixtures are built into hoods.

The latter provide a sufficient level of illumination with minimal electrical energy consumption and an increased service life.

At industrial catering establishments, exhaust hoods are installed above the devices different types: stoves, grills, ovens and so on.

If the umbrella is connected to the ventilation duct of the house, it must be equipped with special valves that prevent the air masses entering the device from returning to the kitchen area.

Types of structures and the problem of choice

Based on the type of design, there are wall-mounted and island-mounted exhaust hoods. The design can be exhaust or supply and exhaust. In the first case, the device only removes exhaust air from the room, in the second it also provides an additional influx of fresh air masses.

When choosing a suitable umbrella, you should take into account the required level of air exchange, the size of the cooking equipment, as well as the intended location for its placement. For an industrial kitchen, it is recommended to install a model whose dimensions are 100 mm larger than the dimensions of the hob.

For the manufacture of such devices, food grade stainless steel is used. The device is usually equipped not only with a grease trap, but also with a carbon filter. Backlighting may be a useful option. Supply and exhaust devices, as the name implies, provide not only the removal and purification of contaminated kitchen air, but also the influx of fresh air masses from the street.

Such umbrellas in living conditions used extremely rarely, this is a technique for professional use. Some operations require constant receipt fresh air. Umbrellas of this type allow you to create an exceptionally favorable microclimate in the workroom, adjust the humidity and air temperature to an acceptable level.

The power of the exhaust element usually exceeds the supply capacity in models of this type by about one third.

The advantage of using an exhaust hood is that it can be installed in almost any suitable place, you just need to choose the right model

Wall umbrellas are mounted not on the ceiling, but on the wall. Typically, such models are used to connect to an exhaust duct. To facilitate installation work, the hob is installed as close as possible to the ventilation duct.

In this case, it will not be too long, which facilitates the effective movement of exhaust air into the ventilation duct.

Wall-mounted hoods can be mounted on the wall. They are more convenient to connect to the building’s ventilation duct than island models

A short design usually does not require many turns when using rigid plastic ducts. There should be no more than three such elbows for one ventilation hood. The beveled type of island hood is very popular, which allows you to bring the hood closer to the maximum permissible distance to the hob.

An island-type umbrella, which is attached to the ceiling, is considered universal. As the name implies, it is used for installation above kitchen island, specifically - above the stove built into it. The peculiarity of the design is that when installing it there is no need to use a wall; the structure is attached to the ceiling.

Such devices are usually used on large kitchens, both industrial and domestic. In small areas, the use of a kitchen umbrella over the island is usually not used due to lack of free space. But such a design may be advisable even in a small kitchen if hob installed near the window.

The presence of two filters allows for sufficient air purification high level so that you can return it to the kitchen area. Of course you should use necessary funds to ensure sufficient air exchange, but recirculation allows you to retain in the room some of the thermal energy that was spent on cooking.

To remove contaminated air using an exhaust hood, it must be connected to a ventilation duct. If this is not possible, use models with circulation and a carbon filter.

Recirculation is used in island hoods, since installing such a unit next to a ventilation hatch is usually quite difficult. Read about how recirculation hoods work. Some models of island umbrellas can be adjusted in height, which allows you to change the intensity of absorption of polluted vapors depending on the situation.

If the location for installing the hood is chosen in such a way that the filtered air cannot be discharged into the ventilation duct, then you will definitely have to give preference to a device with recirculation.

When choosing an exhaust hood for the kitchen, you should choose the right one. The most powerful option is suitable for kitchens up to 25 square meters. m.

However, you should not choose a model with too much power reserve, since the higher the performance, the more noise the hood makes during operation. For a small room this can be a real disaster.

There are exhaust and supply and exhaust hoods. The latter not only ensure the removal of polluted air, but also allow the influx of masses from the street to improve the atmosphere in the room

The noise level of the device is considered acceptable around 40 dB. It may be a little higher (up to 70 dB), but you should not choose an overly noisy model, since the sound of its operation can cause irritation. When choosing the type of control, you should take into account the installation height of the device. If the hood is installed high enough, the remote option can be very useful.

This technique is different at a high price, therefore, when choosing a brand, you should pay attention not only to famous name, but also on guarantee period, as well as the availability of service centers and warranty conditions. Of course, the design of the device also plays an important role. Fortunately, the models of exhaust hoods are very diverse, you can always find a suitable option.

Features of installation and operation

Installing this type of exhaust equipment is relatively easy, but inexperienced craftsmen are still better off entrusting these operations to professionals. If you decide to carry out the installation yourself, you should start with a detailed study of the manufacturer’s instructions.

Hoods are usually made from durable food grade aluminum steel. For industrial enterprises, such designs are often created to order

After this, you need to examine the installation site, carry out required measurements, prepare tools, fasteners, materials, etc. An important point is the correct distance from the hob. It must be at least 60 cm for electric stoves and 70 cm for gas appliances, but not more than 85 cm.

If the umbrella needs to be hung higher, then you should choose a more powerful device to compensate for the difference in height. To install an exhaust ventilation hood, you will need tools that are usually in the arsenal of any experienced craftsman: a tape measure and a building level for marking, a screwdriver, a drill, a hammer, etc.

Depending on the type of device, you will need to either simply hang it above the stove, or connect it with an air duct to the ventilation duct. Either a metal corrugated hose or rigid plastic structures are used as an air duct.

The corrugation can be bent in a suitable way, and to make a plastic elbow, special adapters should be used to ensure a tight connection of individual sections of the air duct.

If the power cord is not long enough, you need to install an additional outlet near the device. You need to make sure that the electrical appliance has the necessary grounding.

Correct installation of the ventilation hood is only half the battle. For the device to work effectively, it is necessary to organize its operation. Detailed information on such issues is contained in the operating instructions supplied with each device.

Regular cleaning is of great importance. For example, aluminum grilles should be washed using special detergents. Good results can also be obtained by using products that can be found in any kitchen: acetic acid, diluted by a third with water, a saturated solution of ordinary laundry soap or a paste mixture of water and baking soda.

Aluminum grease traps for exhaust hoods must be regularly cleaned of accumulated dirt in order for the device to work correctly and efficiently.

These recipes will be useful for those who suffer from intolerance chemicals. Grates should be cleaned of accumulated grease and dirt at least once every three months.

Replacing carbon filters is usually done in the following order:

disconnecting the device from the power supply;
dismantling aluminum grilles;
removing the used filter;
installation of a new filter element;
installation of aluminum grilles;
connecting and checking the operation of the device.

When installing a new filter, you should hear a characteristic click. If, after replacing the filter, unusual sounds appear in the operation of the hood or it becomes noisier, the filter may be installed incorrectly and the work should be redone.

If cleaning and replacing the ventilation hood filters is not carried out in a timely manner, the performance of the device may significantly deteriorate.

Carbon filters are necessary in hoods with circulation; they provide fine air purification and need to be replaced regularly

Removable filters and glasses for collecting grease in umbrella models that are used in catering establishments should be cleaned daily in accordance with the instructions. It is also necessary to constantly clean the outer surface of the housing exhaust device. It is recommended to remove some elements and soak them in special cleaning solutions.

Once cleaning is complete, rinse them thoroughly. Another element that needs periodic cleaning is the air duct. It is necessary to remove the connecting elements and remove deposits from inner surface designs.

Corrugated elements require this cleaning more often than smooth plastic channels. Some industrial models of kitchen umbrellas are equipped with a built-in cleaning system, but such expensive units are usually not used in everyday life.

Conclusions and useful video on the topic

The root of construction troubles is hidden in the little things. Neglecting small details, the owner of a private home ineffectively inflates the family budget with repair costs. But if the owner treats the house as an integral organism in which everything is interconnected, his money does not go down the drain, and costs are limited to routine maintenance. Improper installation of protective devices on the chimney provokes losses - both financial and human.

Installing an umbrella on the chimney helps maintain the operation of the heating system in optimal mode, prevent premature aging of the chimney, and improve air circulation in the house.

Caps and heads on pipes are designed for the following purposes:

cover the ventilation duct, protecting it from rain, snow and dirt. Lack of protection can lead to accumulation large quantity water in the chimney, which contributes to a decrease in draft and, accordingly, a drop in the efficiency of the heating system;
protect the pipe material from damage by removing accumulated condensate due to the presence of special grooves;
prevent insects and birds from falling into the pipe, serve as an obstacle to leaves and branches from falling from trees;
perform a decorative function. Gives the roof a finished look appearance, especially if the design contains elements of artistic forging.

Note! Using an umbrella you can solve one of the problems of dampness in a house or bathhouse. If the pipe is open to all winds and rain, the moisture that gets into it penetrates into the premises. As a result, walls and floors are affected by fungus, and an unpleasant odor appears in the air.

Some types of caps have a design that creates a rarefied environment in the upper part of the pipe. Due to this, improved draft in the chimney is achieved; excess moisture, exhaust air and combustion products.

The perfect functioning of the exhaust ventilation ensures that hot air is removed from kitchen premises, promoting the flow of fresh oxygen into the building. The use of centrifugal fans ensures the creation of a strong air flow, which is the key to effective ventilation.

Duct protection

A well-thought-out ventilation system ensures efficient air flow. Removing heated air, filled with combustion products and all kinds of carcinogenic substances, frees up space in the room, opening up the possibility of replacement with streams of fresh atmospheric oxygen. Most effective option creating a reliable ventilation system is the use of round galvanized air ducts, ensuring the creation of a lightweight and airtight system.

The umbrella is round. Specifications


Umbrella diameter d, mm	Cap diameter D, mm	Height H,mm	Nipple connection Price	Flange connection Price
100	170	220	197	291
125	213	243	197	298
140	238	256	218	324
160	272	274	225	330
180	306	292	480	596
200	340	310	269	384
225	383	333	280	400
250	425	355	290	410
280	476	382	310	463
315	536	414	343	497
355	604	450	452	625
400	680	490	514	696
450	765	535	586	806
500	850	580	845	1066
560	952	634	922	1181
630	1071	597	1134	1431
710	1207	639	1423	2034
800	1360	720	1610	2250
900	1530	810	2250	3161
1000	1700	900	2799	3785
1120	1904	1008	3630	4818
1250	2125	1125	3630	4486

The air exhaust zone on the roofing is equipped with protective devices connected to air ducts. The round umbrella is used for comprehensive protection of the outlet openings of air ventilation systems. Successful combination simple device and high functionality ensures the popularity of using round umbrellas on roofing coverings various designs. Round umbrellas made of galvanized steel have numerous advantages, among which the following characteristics stand out:

A light weight;
Low cost;
Corrosion resistance;
Protection against penetration of atmospheric precipitation;
Unobstructed air flow;
Hit protection foreign objects;
Gives a completed look to the roof structure of the structure.

Quality products from a reliable supplier

The Venti company supplies reliable products for the protection of air duct systems, ensuring the creation effective ventilation protected from the influence of atmospheric factors. Wide selection of different designs and standard sizes allows you to select an instance that exactly matches the diameter of the air ducts, fan power and unique design roofs.

It should be noted that umbrellas ventilation systems They have a completely uncomplicated design. A rectangular chimney hood consists of a main body, a tray for collecting grease and filters that perform. Filters are always installed at an angle of exactly 45 degrees Celsius.

If we are talking about supply and exhaust hoods, then in this case it is necessary to use a grille or a device such as a diffuser.

In some cases, duct hoods are also equipped with additional elements, such as connection lugs, fans, lamps and many others.

1 Operating principle of the ventilation hood

This device works as follows. The air that is subject to the processing process, as a result of which it becomes hot, has a much lower density, and therefore rises to the top, and is replaced by cold air currents.

Then the air enters the pipe and passes through special grease filters, where it is saturated big amount oil vapor, due to which it begins to cool over time.

Ultimately, passing through such a pipe due to strong temperature changes, the oil condenses, air flows begin to separate from it and through special channels allow the fat to flow into the bath.

In turn, the air, which is purified after such a process, enters the round or.

2 Device classification

Today, two types of rectangular umbrellas are used for chimneys:

Exhaust hoods . Their main purpose is the complete elimination unnecessary gases, substances, combustion products from the chimney. Highly heated air flows are drawn in by the umbrella, after which they are transported through a pipe where grease filters are located and are ultimately transported back to the air duct, through which they are removed from the building. All this can be easily done with your own hands.
Supply and exhaust hoods . Thanks to them, both the exhaust of polluted air and the flow of new, clean air into the room are ensured. These umbrellas are best used in rooms where the flow of clean air is limited due to certain circumstances. It is always necessary to carry out calculations taking into account the fact that the volumes of supplied and extracted air flows will always differ from each other. Therefore, in no case should you count on the fact that exhaust hoods will contribute to the complete destruction of odors, gases and other substances. Although the chimney, of course, will work much more efficiently.

There is also a classification according to the type of construction. Thus, exhaust and supply and exhaust rectangular and round umbrellas are divided into island and wall.

2.1 DIY installation and calculation features

I would like to note that installing such umbrellas with your own hands is quite possible, since in fact there is nothing complicated in such work. Below are some of the most popular ways to install a chimney umbrella.

Method number 1. Installation of wall-mounted exhaust hoods using anchors. After a certain calculation, the length of the umbrella is selected and 2 or 3 equal holes are drilled in the back of the wall. Using enlarged models of washers, the exhaust hood is first attracted and then installed on the wall. It is very important that the wall is perfectly level.
Do-it-yourself installation of rectangular umbrellas through collets and studs to the ceiling. At the very beginning, you need to drill 4 identical holes for the studs. All these holes are drilled strictly along the edges of the umbrella, after which the device is attached directly to the ceiling. A modern chimney works perfectly if applied this option. The only negative is that the calculation of the ceiling height to the standard stud length does not allow the use this technology, if the height of the room is more than 4 meters.
Installation of chimney exhaust hoods using various cables and chains through anchors and brackets to the ceiling. In order to do everything yourself, you need to weld 4 brackets of the required parameters to the upper horizontal part of the umbrella, and then use a carabiner to securely fix the chain or cable. The second end of such a chain or cable must also be securely connected to the ceiling. Among the disadvantages of this method, one can note the unsteadiness of the structure, so tying it with air ducts is not at all easy, but for a chimney this scheme is excellent.

As you can see, installing it yourself is not at all difficult. The main thing is to adjust the umbrella as close as possible to the chimney pipe and take into account some nuances.

Application area

Supply and exhaust and exhaust hoods of ventilation systems are widely used today by industrial enterprises and beyond. Such systems are widely used in public catering establishments, such as restaurants, canteens, bars, food factories, cafes, and so on.

Umbrellas are also installed over all kinds of devices. thermal equipment, in particular this applies to deep fryers, gas stoves, and ovens. If the calculations made allow the installation of such umbrellas, then they are used in various industrial premises - food, pharmacological, physical, chemical.

2.2 This is what a rectangular ventilation umbrella looks like - video

If you take a closer look at the chimneys and ventilation pipes of residential buildings, the variety of chimneys on them (deflectors, weather vanes) is amazing. But the main task of the deflector is not to decorate the chimney, but to increase and stabilize draft depending on the weather, and thereby improve the efficiency of the heating device and reduce heating costs. A deflector on a vent pipe can provide energy-independent (and free) supply and exhaust ventilation, see below. But at the same time, there are also plenty of opponents of installing deflectors on the pipes of residential buildings, and they provide compelling arguments in their favor. The purpose of this article is to help the reader understand in what cases it makes sense to install a deflector on a chimney or ventilation, and then how to choose the right one or make it yourself.

The most important question

Before selecting or making a deflector for a pipe, you need to decide - is it needed at all? The deflector may freeze, be covered with soot or carbon deposits (coked), clogged with fallen leaves, wind-blown debris or dust. In any of these cases, if the deflector is on the chimney, the inhabitants of the house are at risk of getting burned. The deflector does not increase the efficiency of a furnace or boiler much, but it requires regular inspection and cleaning. At least once every 3 months for stoves on solid fuel and at least once every six months for gas, liquid fuel or pyrolysis furnaces and boilers. For more information on the dangers that can result from installing an unsuitable deflector on a pipe, see the video:

Video: what are the dangers of deflectors, umbrellas and weather vanes on a chimney?

Therefore, if you have an old wood or coal stove, but the draft is not good and the wind is blowing into the chimney, instead of a complex deflector it is better to install a simple chimney, for example. umbrella or tent. And in other cases, you need to thoroughly understand which deflector is needed for this particular stove/boiler with this particular chimney. It is also important not to confuse a smoke deflector with a ventilation one - small traders and the authors of some popular publications do not see or do not make the difference between them.

Evolution of the deflector

Deflectio in Latin means “I reflect” in the sense of “throwing away.” Not directed in a certain way, like a reflector, but just to the side. A cap for a chimney pipe made of skins, large shells, etc. already installed primitive people to avoid wind blowing into the pipe.

The role of the deflector in creating thrust, its stabilization despite the vagaries of the weather and the ability of the deflector to increase the efficiency of heat-generating devices was first seriously thought about at TsAGI almost 100 years ago on the instructions of the newly hatched Soviet government. Before that, heating engineers tried to improve chimneys for this purpose. Have you seen in old photographs the huge pot-bellied pipes of American steam locomotives, like an inverted pear, or the long thin ones of English ones with a rosette at the top?

At TsAGI, the venerable aircraft designer D. P. Grigorovich worked on deflectors in creative collaboration with A. F. Volpert, who was fluent in mathematical apparatus. The latter is also, and even more, known for his work in the field of radio engineering (Wolpert-Smith diagram, etc.). Together and separately, Grigorovich and Volpert developed several types of deflectors for various purposes, therefore, various deflectors of Grigorovich, Volpert and Volpert-Grigorovich are described in the specialized literature.

Grigorovich began by aerodynamically correctly calculating an ordinary smoke umbrella, pos. 1 in Fig. This has already significantly improved the performance of the device; Grigorovich cone - remember, it will be very useful. Wolpert proposed to equip the umbrella deflector with an aerodynamic skirt-diffuser (item 2), but the deflector remained aerodynamically imperfect, see below. It was supplemented with a streamlined body of rotation instead of a cap and a cylindrical body-shell. In the end, after repeated blowing in a wind tunnel, the government commission was presented with a TsAGI deflector (item 3), which fully satisfied the issued technical specifications and far exceeded it.

The TsAGI deflector is still the most common in the world due to its technical excellence. There are modifications of them for different purposes, see below. But other developments of Grigorovich and Volpert were not in vain - most models of modern smoke deflectors are developed on their basis. Which one is more suitable for what, we will talk about this further.

Types and schemes

The entire variety of trade names of smoke deflectors fits into a limited number of design types and aerodynamic designs. First of all, according to their interaction with the natural draft of the chimney, deflectors are divided into:

Active - with a built-in working smoke exhauster. To ensure the specified characteristics of the deflector, the smoke exhauster must operate continuously while it is burning in the firebox.
Active-passive – low-power smoke exhauster extreme case: complete calm, storm, excessively intense fire, etc. Minimum allowable specifications the chimney is provided even when the smoke exhauster is turned off.
Passive-active - the deflector creates a small amount of its own thrust in a non-volatile way.
Passive – there is no deflector’s own draft.

Active deflectors as energy-dependent and not optimal for home heating devices low power we do not consider further. Of the active-passive ones, we will consider one, designed for a low-power 12 V fan and suitable for DIY manufacture.

According to the aerodynamic design of the chimney deflector, it is possible to make a trace. way (above in the figure):

Aerodynamically imperfect (incomplete) - in the space occupied by the deflector there is a “pocket” - a winding area in which air accumulation is possible, flue gases or mixtures thereof;
Aerodynamically fully open - there is no wind pocket, but the wind has free access to the working space of the deflector;
Aerodynamically perfect closed - there is no wind pocket, the wind does not have free access to the working space;
Deflector-vane (see below);
Vortex deflector.

An aerodynamically perfect closed deflector is the most complex structurally and technologically, but has a huge advantage: due to heating of the shell, almost all aerodynamically perfect closed deflectors provide their own energy-independent thrust. This is the only one passive type a deflector capable of increasing the natural draft of the chimney in complete calm.

Note: an aerodynamically perfect closed deflector is the TsAGI deflector mentioned above. This aerodynamic design was invented precisely at TsAGI.

Vortex deflectors are easily recognized by their “ragged” design with sharp protrusions. In their aerodynamics, as in vortex aerodynamics in general, there is still much that is unclear (the Navier-Stokes equation was solved in general view just 2 years ago). Predict the behavior of a vortex deflector for any external conditions It’s definitely not possible with any chimney. Therefore, vortex deflectors are not considered further. Whether or not to believe their manufacturers is your own business.

Aerodynamics

There are enough diagrams of flue gas flow in deflectors in publicly available sources. But from the point of view of the homeowner and the craftsman, the nature of the interaction of the deflector with the natural draft of the chimney and the wind in the wake is more important. aspects:

Will the deflector worsen the original draft?
Is the deflector capable of increasing the initial thrust in calm conditions?
How much and how does the deflector increase wind loads on the pipe?
How prone is the deflector of this design to icing/clogging and is it easy to clean?

Then it is better to consider the wind not according to the meteorological scale, but according to the rough gradation of force and the dynamics of the velocity field:

calm;
weak/medium (moderate) – up to 6 points on the weather scale;
strong – 6-8 points;
very strong – over 8 points;
gusty - the wind of any strength is really gusty, or sharp (strongly sloping up or down), or turbulent.

An idea of the aerodynamic properties of passive smoke deflectors is given in Fig. higher.

Simple cap

An ordinary chimney smoker in the form of an umbrella, if it is made in the form of a Grigorovich cone, is not so bad:

With a massive heat-intensive chimney, it keeps the draft within the permissible limits for a wood/coal stove in even winds up to a severe storm (10 points).
In any wind, up to hurricane force, it does not create destructive loads on the pipe; It's more likely to break loose and fly away.
Structurally simple.
Low coking and clogging, easy to clean in order annual inspection and chimney maintenance.
Due to imperfect aerodynamics, it is little sensitive to the configuration of the umbrella. If the house is in the wind, the chimney-umbrella can be made into a tent (see figure on the right), which simplifies the work and provides greater opportunities for its design.
With a 2-3 channel chimney (see below) it provides technical performance (except for increased draft in calm conditions) no worse than an aerodynamically perfect closed deflector.

The disadvantages of an imperfect smoke deflector are also quite serious:

In calm conditions, the initial draft decreases the more strongly, the more intensively the stove is heated. What is especially dangerous in the harsh, quiet winter: the stove can choke and puff out fumes.
On strong wind capable of creating excess thrust, which sharply reduces the efficiency of compact channel furnaces(for example, Dutch for 2.5-3.5 bricks) and fireplaces.
In very strong/gusty winds, blowing into the pipe and causing reverse draft cannot be ruled out.

In general, an imperfect deflector-umbrella is the optimal smoke vent for a brick chimney of a properly built and well-maintained solid fuel house stove, operated in places where hurricanes and storms are extremely rare. There are ways to make a smoke umbrella uninflated (see below), but they complicate it to the point that most often you have to choose an aerodynamically complete or perfect deflector.

Open

The aerodynamically open deflector does not reduce the initial draft and, in any wind, keeps it within the limits acceptable for stoves and boilers using solid, liquid fuel and gas. It freezes quite heavily, becomes coked and littered, but is easily accessible for cleaning. Its disadvantages are:

A streamlined body of rotation instead of a cap is a technologically complex unit.
The resulting vector of wind loads is such that an aerodynamically open deflector tends to collapse the pipe, while an umbrella tends to fly off it.
In winds stronger than force 8, the lateral load on the pipe increases sharply and then grows according to a power law.
Doesn't extinguish well dynamic load from gusts of wind, so an open deflector cannot be placed on a brick pipe.
Unsuitable for pyrolysis heat-generating devices: in a strong wind it immediately sucks out the pyrolysis gases and the stove/boiler goes out.
Not very suitable for design: blotches and figures spoil the overall aerodynamics. The only places where it is possible to place decorations are the upper pole of the body of rotation and the lower edge of the diffuser (see below).

Note: At one time, we and the USA conducted experiments on the use of open deflectors on steam locomotives to increase efficiency at low speed. The result was disastrous - at mid-speed a tongue of flame appeared from the pipe, and none of them could accelerate to the design speed.

In general, an aerodynamically open deflector is suitable for all types of heating devices, except pyrolysis ones. Provided that the deflector is inspected and cleaned at least once every 2 months, and the draft is checked before each firebox. Very well suited for chimneys with insufficient draft and, especially, for sauna stoves: there have been no cases of fires in saunas due to an open deflector. Properly heating a bathhouse is not an easy task, and checking the deflector will not significantly complicate it.

Note: There are types of open deflectors that create virtually no lateral loads on the pipe and are suitable for fragile ceramic and glass chimneys, see fig. on right. However, dust, debris and soot accumulate in the open rotating body, which spoils the aerodynamics of the device and makes it difficult to clean. Therefore, manufacturers recommend such products only for gas boilers in places with not very dusty air.

Perfect

The advantages of an aerodynamically perfect closed deflector are partially indicated above. Besides:

An aerodynamically perfect closed deflector ensures traction stability in any external conditions, sufficient for any household stoves and boilers.
It does not clog or freeze inside, and ice and dust outside have little effect on its operation.
With minor modifications it is suitable for use as both smoke and ventilation non-volatile, see below.
It perfectly absorbs dynamic loads from wind gusts and is therefore suitable for installation on pipes made of any materials.
2-3-4 chimneys can converge into one oval, triangular or square shell in a bundle.

The disadvantages of a closed deflector are not so significant:

The lateral force on the pipe in a strong wind gives more than an open one, but then with increasing wind it increases linearly, i.e. the pipe under the open deflector can always be reinforced or reinforced with guy wires.
Quite complex structurally and technologically.
Unsuitable for design: any blotches and figures spoil the overall aerodynamics, and the coloring only enhances the utilitarian appearance of the deflector.

Technological tricks

The first rule is don’t make chimneys like gable roof or cylinder vault (see figure on the right). These are suitable for their intended purpose only for mobile devices, when the axis of the umbrella can be arbitrarily oriented with the wind. Or as decorative for a false chimney. There is such a fashion in houses with bio-fireplaces. And in other cases, the craving will follow the will of the elements, even to the contrary.

Next, to make a chimney deflector with your own hands, you need to master some tinsmithing techniques. First of all, connecting the sheets into a fold (fold), or folding, see fig. below. Most often, the parts of the deflectors are connected with a single recumbent seam, but for umbrellas of imperfect deflectors in decorative purposes sometimes a double standing seam is used.

Round umbrella:

Pyramidal (tent) umbrella with the top in the center:

Elongated faceted umbrella:

Transition from a square to a circle (a square inside a circle):

Very important for closed baffles for low-power furnaces and boilers, see below.

Moving from circle to circle:

All these patterns can be constructed using only a ruler and a goat’s leg compass (into which a pencil is inserted. Well, for those who are inclined to study the basics in depth, before getting down to business, we provide a selection of projections and formulas for accurately constructing part developments. Pay attention to the elongated umbrellas: they are placed on 2-3 way chimneys. Smoke channels, each of the minimum cross-section allowed for a given heating device, are placed in a row. The probability of blowing out 2 channels at once is extremely small, and all 3 are practically absent.

Here in Fig. - data for constructing a truncated cone, of which there are more than enough in deflectors. The initial data is the height of the cone H, the radii of the apex and base R1, R2. Also pay attention to the inset marked in red: this is a development of the same Grigorovich cone. The forming angle (in this case 30 degrees) is found as φ = arcsin(H/r), where H is the height of the cone, and r is the radius of the base. The radius R is determined similarly to L for a truncated cone, but H and r are squared. However, for those who have not forgotten the Pythagorean theorem, this is already clear.

After the cones, it will not be difficult to figure out the development of a single-center tent, see fig. There is only one “but”: the allowance in the example of the pattern (on the right in the figure) is given based on a single riveting (for strength) solder seam.

To connect metal up to 0.6 mm thick into a single fold, an allowance of 20 mm must be taken on one side, and 21+2+20 mm on the other. If the metal is 0.6-1.5 mm, then 30 and 31.5+3+30 mm respectively. But, generally speaking, a seam soldered and riveted at the edge is easier to make, it looks neater and resists corrosion better than a folded one. If the roof is covered with iron, then, of course, riveting and soldering the sheets is simply technically impossible. But the deflector umbrella is a different matter. It is assembled by soldering and riveting like this:

Mark and cut out the development;
Drill holes for the rivet;
Bend the sides (wings) of the allowance inward at 90 degrees;
Rivet the edge;
The sides are compressed through wooden backing bars with clamps;
Solder the seam.

In a similar way, a sweep is built and the hip tent (umbrella) of the chimney is assembled, see fig.

And finally, the most complex detail: the diffuser of an aerodynamically perfect closed deflector, also known as an adapter-skirt from a square to a circle (circle inside) for installing a smoke umbrella on a brick pipe. The construction rules are not complicated (see figure), but they require precision and accuracy in work.

Note: additionally equalize the draft of the open and imperfect deflectors by round pipe, and also the probability of blowing into the latter can be reduced to negligible if the diffuser/skirt generatrix is bent inward, see fig. But the work is so complicated - after assembling the adapter from circle to circle, it needs to be knocked out on a block of hard wood.

Constructions

Now let's see what is possible and how to make a deflector for a chimney yourself. It's easiest to start with an imperfect umbrella deflector; its capabilities are much wider than it might seem, and few materials and not very complicated work are required.

What can an umbrella do?

IN climatic conditions An RF deflector-umbrella on a chimney is most often sufficient, especially since fumes caused by it are also not noted. But - if the smoke umbrella is made correctly. The most common mistake is that the cap is raised too high on the racks. This will not help return 100% of the original draft, but the likelihood of blowing into the pipe increases sharply.

The correct dimensions of the deflector-umbrella for the chimney are given on the left in Fig. For pipes with a clearance of 100-200 mm in diameter, they decrease proportionally, and then the value of H1 increases by 1.3 times for pipes of 150-200 mm and 1.6 times for pipes of 100-150 mm.

On the right in Fig. The dimensions of a non-inflating deflector-umbrella are given, but in Russian Federation conditions it is better to install it on a ventilation pipe natural ventilation, because the mesh quickly becomes overgrown with soot or flue gas condensate, and then dust sticks to it very well.

It also does not blow out, retains the original draft and even slightly increases it with a two-story deflector-umbrella. The diagram of its action is given in pos. 1 next rice.:

For chimneys of low-power household stoves/boilers (up to approximately 40 kW), it can be simplified by making the floors the same, pos. 2. Each floor is a Grigorovich cone cut in half in height (see above); the distance between floors is equal to the height of the floor. Top floor pincer, i.e. the cut off top of the cone is closed with a blind lid. A 3-story umbrella for a ventilation pipe (item 3) freezes less often and clogs less than an umbrella with a mesh. For pipes 130-200 mm, the dimensions change proportionally. And finally, the Kiryushkin deflector (item 3; all cones are Grigorovich) is used primarily as an active-passive one - a low-power smoke exhauster at 12 V 100-200 mA is placed under the small cone.

TsAGI

Before taking on the aerodynamically open deflector, let's see how it is modified for a private house TsAGI's most advanced deflector. Its original design was designed primarily for industrial facilities and then to apartment buildings.

Drawings of 3 versions of the TsAGI deflector are shown in Fig. Original dimensions industrial version are shown at the top right. Not completely, because It is designed for a durable pipe and certainly not for a sandwich chimney. For a chimney of a private household, a Khanzhenkov deflector operating according to the same scheme (on the left in the figure) is more suitable. It produces less horizontal wind load and can be inserted into a pipe as described below.

And on the right in Fig. – dimensions of the TsAGI ventilation deflector. It can be converted from passive to passive-active by painting the shell with blacksmith's putty or other paint that well absorbs thermal radiation from the earth and objects surrounding the house. Of course, you should leave the fans in the vents of your home ventilation system, but you will have to turn them on occasionally. How to make a TsAGI deflector with your own hands, see video

Video: do-it-yourself TsAGI deflector made of metal tiles

Note: ventilation deflector not such a luxury as it might seem. When the wind blows through the vents, the bathroom is cold, and kitchen fumes and toilet odors are carried throughout the house. Fire valves do not solve the problem - if they slam shut, the bathroom and kitchen are stuffy.

What comes out of cones

From deflectors open type most accessible, and throughout the complex technical indicators, the Volpert-Grigorovich deflector is optimal for private households. Although, only they themselves knew how much of both there actually was in it.

The canonical (based on TsAGI studies) proportions of the Volpert-Grigorovich deflector are given in pos. 1 pic:

On the left is a modification for an asbestos-cement pipe that holds well longitudinal loads, but fragile across. The doubled height of the upper cone forming the body of rotation gives a greater lifting force, tending to tear the deflector off the pipe, but a tight clamp will hold it in any wind. For pipes 130-180 mm inside, the dimensions change proportionally.

Note: For another version of the homemade Volpert-Grigorovich deflector, see next. video clip:

Video: Volpert Grigorovich deflector to increase draft in the furnace

Weather vanes

Pipe deflectors - weather vanes are also called weather vanes. Sometimes all chimneys in general are called this, but this is incorrect, because... A weather vane is, by definition, a rotating device.

The deflector on the pipe - weather vane can be made rotary, self-orienting and rotating. The latter are also called turbo deflectors, and self-orienting smoke teeth, which is also incorrect. The smoke tooth is part of the chimney of an English fireplace. The weak point of all weather vane deflectors is the bearing. It becomes very easily clogged and covered with soot, and the seals are subject to increased wear. Therefore, you need to inspect the weather vane deflector at least once every 2 months. But the weather vane deflector itself almost never becomes overgrown with the main enemy of all fixed deflectors - icicles.

Pipe deflectors - weather vanes

A multi-bladed weather vane deflector (items 1 and 2 in the figure) provides stable draft in winds of up to 9-10 points with minor loads on the pipe, so it can be installed on sandwich, ceramic and glass chimneys. A single-blade weather vane deflector puts a lot of stress on the pipe in a strong wind, so it must be strong and the house must be located in a place where the storm wind will not blow up. But a single-bladed weather vane deflector can easily be designed in the shape of a bird (items 3 and 4).

Turbo deflector (item 5) – remember and don’t trust anyone – not smoke! It is ventilated or for gas boilers with electric ignition. The turbine rotates both by the wind and by the air current in the pipe, and a correctly made turbine, as in some types of wind engines, is self-spinning: the weakest initial thrust or a light breath of breeze is enough for the turbine to spin and draw air, and it will stop only when the thrust , and the wind will stop completely. In a house ventilation system with turbo deflectors, you have to turn on the fans in the vents, as they say, once a year, not every year. Unfortunately, the turbo deflector is easily filled with dust and debris from the air, so it also needs to be checked at least once every 2 months.

The technical properties of the turbo deflector are the same as those of a multi-bladed self-orienting one, but it loads the pipe even less. It is quite possible to make a turbo deflector with your own hands, see the video below.

Video: DIY turbo deflector

How to install a deflector

It is possible to install a deflector on the pipe only if the chimney is made exactly according to the rules of SNiP 41-01-2003, pos. 1 in Fig. below. It is highly desirable that the pipe on which the deflector will be installed is located on the roof slope leeward relative to the direction of the prevailing winds. For reference, leeward means opposite to the direction from which the wind is blowing.

Attach the deflector to the otter (upper extension brick pipe) is certainly possible only if the pipe was originally designed for the deflector. If not, or there are even the slightest irregularities in the pipe laying, the deflector must be attached to it as shown in pos. 2 rice:

A strong sleeve (glass; square-circle adapter) C is inserted into the pipe;
The glasses are secured with blind anchors A at a level no higher than the bottom row of the otter masonry and with embedded pins Z in the grooves at the mouth of the pipe. Anchors and mortgages are walled up cement-sand mortar from M200;
A diffuser/skirt D with a cornice (reflection) K is placed on the glass. Mandatory for a deflector of any design, incl. imperfect!
The diffuser is attached only to the masonry with small anchor bolts. Not with self-tapping screws in plastic dowels! The skirt/diffuser is not attached to the glass!
The working structure of the deflector is firmly secured to the collar (top edge) of the skirt/diffuser.

Only with this method of fastening will the deflector never loosen an old and/or undesigned brick pipe.