Such simple thing, like a cap on a chimney pipe, raises many questions: what should it be like, how to make a cap with your own hands, and in general, is it necessary to install it? Discussions and disputes on this topic occupy more than one page of the popular forum, but you will not find a definite answer there. Let's try to solve these problems ourselves, starting with the need to install a protective cap.

Chimney umbrella - pros and cons

The following arguments speak in favor of installing various caps (other names: fungus, umbrella, weather vane, chimney) on chimney heads:

• the umbrella partially covers the mouth from being blown in by the wind and thus reduces the likelihood of the draft overturning;
• the chimney serves as protection against the ingress of debris and moisture in the form of precipitation;
• if you use a mesh structure, then birds will not be able to nest inside the chimney;
• the product extends the service life of the head brick pipe, destroyed by wind, rain and snow;
• fungus with decorative elements complements the architectural style of the building.

The hood is equipped with a mesh on the sides to protect the chimney from birds.

Now let's look at the counterarguments. The main negative point is that the chimney cap in the form of a fungus stands in the way of combustion products. That is, it prevents the free escape of gases, creating noticeable aerodynamic resistance. This means that the chimney umbrella does not increase draft, but, on the contrary, reduces it.

The second disadvantage of using attachments has been repeatedly confirmed by sad statistics. The fact is that one of the products of combustion of hydrocarbons is water vapor, which escapes into the atmosphere along with smoke. Diesel and high-efficiency engines emit gases with low temperatures (up to 120 °C). As they rise through the pipe, they cool and then come into contact with the metal of the cap.

Examples of icing on chimneys equipped with nozzles

The water vapor immediately condenses and sub-zero temperature freezes, causing icicles to form on the umbrella, blocking the cross-section of the chimney, as shown in the photo. As a result, fumes enter the room and poison the residents of the house. There are other arguments against installing fungi:

1. In modern round chimneys there is no place for birds to live, so there is no need to cover them with a net.
2. A properly constructed flue channel has a condensate collector at the bottom with a drain, where water that has entered the pipe in the form of precipitation will safely drain.
3. Thin galvanized caps installed on chimneys of solid fuel boilers and stoves burn out within 3-5 years due to constant contact with high temperature gases (150-200 °C). It is necessary to install a stainless steel reflector, which increases the price of the product.

Regarding the installation of umbrellas on chimneys, regulations from different countries are put forward different requirements. For example, in European countries it is allowed to mount nozzles only on ventilation ducts, and on chimneys is strictly prohibited. In Ukraine, caps cannot be placed on pipes connected to gas boilers. IN Russian Federation and there is no direct ban in Belarus, but the wording of SNiP is very vague:

“Deflectors, umbrellas and other attachments on chimneys should not interfere with the free exit of combustion products.”

In this chimney, emissions pass through a through pipe and do not encounter obstacles

We suggest approaching the issue from the point of view of safety and practicality, and only then thinking about beauty. Before making and installing a cap on the chimney, consider the following recommendations:

1. Round steel pipes, which remove smoke from highly efficient boilers with an efficiency of more than 85%, cannot be covered with a traditional fungus. Use a conical nozzle in the form of an open nozzle, which will not freeze up in any frost.
2. A brick chimney without inserts, connected to a high-efficiency heat generator, can be protected with a cap-shaped nozzle with a pipe passing through, as is done in the photo.
3. It is allowed to install umbrellas on vertical ducts from stoves. So that the iron visor performs for a long time protective function on the chimney, provide a stainless steel plate inside.
4. It is highly advisable to install gable or hip hoods on smoke exhaust blocks made of brick and equipped with side vents. The goal is to protect the upper part of the masonry from precipitation and wind, without touching the flue openings on the sides.

It is noticeable here that the cap does not prevent smoke from escaping through the side vents, but over 15 years of operation, the iron above the flue has become covered with rust

To protect brick block where exhaust and chimney pipes are open at the top, order or make a box with several through pipes inserted into these channels. Place regular mushrooms on top of the ventilation terminals, and conical nozzles on the gas terminals, as shown in the photo.

Exhaust and smoke ducts are equipped with different nozzles

How to make a chimney canopy

First of all you need to find out external dimensions the head where you plan to attach the umbrella, and then sketch out a hand-drawn sketch depicting the future structure. To develop it, use simple rules:

• the dimensions or diameter of the product must be 10 cm larger than the dimensions of the pipe, so that the edges protrude 50 mm on all sides;
• slope angle of the slopes – from 30 to 45°;
• the minimum height from the chimney cut to the fungus is 100 mm, as shown in the drawing.

In addition to the traditional umbrella, there are other design options - a deflector and a rotating weather vane - “sycophant”. The first allows due to wind pressure, which creates a vacuum inside the cylindrical body, where the smoke channel exits. But in calm weather this device not only loses its advantages, but also worsens the traction force in the pipe, creating increased resistance at the exit of combustion products.

Diagram of the deflector operation - the wind creates a vacuum inside the hood

For reference. The same effect is created by rotating spherical nozzles, an example of which is shown in the picture.

The attachment is beautiful, but not very effective or reliable

A semi-cylindrical weather vane, assembled from several segments and rotating on a special bearing, was called a “sycophant” due to its ability to turn with the wind. If it were not for the high price and dubious reliability of the bearing, it would be an ideal cap for any round chimney, since it successfully protects the mouth from blowing and precipitation.

The weather vane helps well against being blown by the wind, but it can break due to strong gusts

The production of chimney canopies is various materials– thin sheet steel with zinc and polymer coating, stainless steel and even copper. To make a pipe cap with your own hands, we recommend the first 2 options - galvanized or painted metal with a thickness of at least 0.5 mm.

Making a simple round mushroom

To complete this work you will need ordinary tools– metal scissors, drill, hammer and device for setting rivets. Having determined the required size of the fungus, proceed in this order:

1. Screw 2 screws into the wooden strip at a distance equal to the radius of the product plus 15 mm. Get an improvised compass, with whose help mark the center of the circle on the metal and draw its outline.
2. Cut the workpiece with scissors, and then draw a sector with an arc length of approximately 120 mm (the figure resembles the first piece of a round cake).
3. Cut out this wedge, then forcefully align the outer edges of the circle and secure them in a vice.
4. Drill 3 holes along the resulting seam and connect the ends of the part with rivets or M4 screws with nuts. The upper part of the weather vane is ready.

Drawing a circle on a galvanized sheet (left) and joining the edges of the fungus (photo on the right)

The legs for the fungus and the clamp surrounding the pipe are made of steel strips made by bending a thin sheet 2-3 times. These parts are also attached to the umbrella with rivets, which is clearly demonstrated by the master in the video:

Rectangular gable umbrella

To produce this type of cap, it is advisable to use a sheet bending machine or contact the appropriate workshop for this service. In extreme cases, you will have to bend the elements manually along the line, carefully tapping the metal with a rubber hammer on a wooden block.

As in the previous version, the first step is to remove the external dimensions brick chimney, and then calculate and sketch the pattern, as shown in the drawing. Formulas for determining the length of the sides of the elements depending on the initial dimensions of the pipe and the height of the wind vane are also given here.

Advice. The lower part, surrounding the mouth of the smoke channel, is best made in the form of a Z-shaped profile with angles of 90°, which will subsequently “sit” on top of the head. These profiles are then connected into a single frame using rivets.

Assembling the frame and installing the racks in the corners, fastening is done with rivets

Making a pipe cap with your own hands is relatively simple - you need to cut the metal according to the drawing, bend it along the dashed lines and connect the parts with rivets. It is proposed to take ready-made corners made of painted metal with a thickness of 0.5-0.7 mm as rigid racks. How to assemble a gable weather vane and a canopy in the form of a cover with a pipe passage is clearly shown in the video:

Conclusion

As you probably noticed, to make a round and rectangular chimney cap you don’t need to be a master of tinsmithing. It is enough to have the desire, patience and time to save money on the purchase of this simple part. For those who are not too interested in traditional mushroom designs, we suggest watching the latest video on self-assembly weather vane - “sycophant”.

Arguments against installing a cap

Familiarizing yourself with them makes it difficult to make a final decision, but you should be aware of them. Only complete information makes it possible to make the optimal choice, taking into account the maximum number of different factors.

The cap may interfere with draft

This warning has the right to exist only in one case - the cap is set very low, the size of the cracks around the perimeter is smaller than the diameter of the chimney pipe. This happens very rarely; no one deliberately covers the chimney with a cap.

The cap can only interfere with draft if it is set too low

Condensation may freeze on the cap and partially or completely block the hole

Unfortunately, such cases happen quite often. It all depends on the climatic conditions of the area where the building is located, the coefficient useful action boiler and physical characteristics fuel. If everything is clear with the first factor, then the last two should be discussed in more detail.

Building codes and regulations strictly regulate the temperature of the gases leaving the chimney. It should not be less than +120°C, only under such conditions the appearance of condensation is excluded. But modern heating boilers have a very high efficiency, which means that the maximum amount of thermal energy is transferred to the heat exchanger, and accordingly, the gas outlet temperature is low. Not a single boiler can withstand the recommended values; they all heat interior spaces, not the street.

Condensation in the chimney

Conclusion - condensation will be not only on the cap, but also on that part of the chimney where the temperature is below the established standards. This should always be taken into account when attempting to cover chimneys with additional elements.

How to eliminate condensation in a chimney

The amount of condensate depends on the type and characteristics of the fuel. If the boiler is heated with wet wood, then the condensate will have to be collected daily in ten-liter containers, and if it is high-quality natural gas, then it is almost completely absent.

If the stove or fireplace uses solid fuel, it is important that it is dry

Conclusion. Make the decision to install a cap taking into account the factors described above; they have a decisive influence on traction performance and can cause extremely dangerous situations.

Caps burn out quickly and have to be replaced frequently

If the products are made of low-quality metal that is not protected from corrosion, then yes, their service life does not exceed 3–5 years. But today, either galvanized or alloyed sheet steel is used for such purposes. The service life of high-quality stainless steel is practically unlimited.

Stainless steel caps have a long service life

Manufacturing technology of the Tsaga deflector with drawing

Manufacturing drawing of the Tsaga deflector. (Click to enlarge)

First you need to decide on the dimensions of the external and internal pipes. Measurements must be accurate.

The outer diameter of the stove hood fits tightly onto the chimney pipe.

The main parts are made in proportion to the internal diameter:

• the inlet pipe is placed on the pipe;
• the outer cylinder is a diffuser, its size should be approximately 30% larger than the internal diameter of the pipe;
• cover, its size should be about 90% of the pipe diameter.

Please note: although the installation of a deflector or nozzle may be simple, the proportion must be maintained, and if this is disturbed, the expected result of traction will be lost. . A drawing is made on paper to match the shape and dimensions of the cap.

1. A drawing is made on paper to match the shape and dimensions of the cap.
2. The patterns are applied to a metal surface and cut out with metal scissors.
3. The resulting parts must be bent according to the design and connected with rivets.
4. The finished parts of the deflector are assembled in the workshop, and at a height they are only fixed above the pipeline.

Please note: install the smoke shaft correctly at a height of up to 2 meters above the roof level. Remember that work carried out at height requires special care and compliance with safety regulations.

How to make a visor

First of all, you need to find out the external dimensions of the head where you plan to attach the umbrella, and then sketch out a hand-drawn sketch depicting the future structure. To develop it, use simple rules:

• the dimensions or diameter of the product must be 10 cm larger than the dimensions of the pipe, so that the edges protrude 50 mm on all sides;
• slope angle of the slopes – from 30 to 45°;
• the minimum height from the chimney cut to the fungus is 100 mm, as shown in the drawing.

In addition to the traditional umbrella, there are other design options - a deflector and a rotating weather vane - “sycophant”. The first allows you to actually increase traction due to wind pressure, which creates a vacuum inside the cylindrical body, where the smoke channel exits. But in calm weather, this device not only loses its advantages, but also worsens the traction force in the pipe, creating increased resistance at the exit of combustion products.

Deflector operation diagram

For reference. The same effect is created by rotating spherical nozzles, an example of which is shown in the picture.

The attachment is beautiful, but not very effective

A semi-cylindrical weather vane, assembled from several segments and rotating on a special bearing, was called a “sycophant” due to its ability to turn with the wind. If it were not for the high price and dubious reliability of the bearing, it would be an ideal cap for any round chimney, since it successfully protects the mouth from blowing and precipitation.

Various materials are used to make chimney canopies - thin sheet steel with zinc and polymer coating, stainless steel and even copper. To make a pipe cap with your own hands, we recommend the first 2 options - galvanized or painted metal with a thickness of at least 0.5 mm.

Making a simple round umbrella

To perform this work, you will need the usual tools - metal scissors, a drill, a hammer and a device for setting rivets. Having determined the required size of the fungus, proceed in this order:

1. Screw 2 screws into the wooden strip at a distance equal to the radius of the product plus 15 mm. Get an improvised compass, with whose help mark the center of the circle on the metal and draw its outline.
2. Cut the workpiece with scissors, and then draw a sector with an arc length of approximately 120 mm (the figure resembles the first piece of a round cake).
3. Cut out this wedge, then forcefully align the outer edges of the circle and secure them in a vice.
4. Drill 3 holes along the resulting seam and connect the ends of the part with rivets or M4 screws with nuts. The upper part of the weather vane is ready.

Drawing a circle (left) and connecting the edges of the fungus (right)

The legs for the fungus and the clamp surrounding the pipe are made of steel strips made by bending a thin sheet 2-3 times. These parts are also attached to the umbrella with rivets, which is clearly demonstrated by the master in the video:

Gable weather vane

To produce this type of cap, it is advisable to use a sheet bending machine or contact the appropriate workshop for this service. In extreme cases, you will have to bend the elements manually along the line, carefully tapping the metal with a rubber hammer on a wooden block.

As in the previous version, the first step is to take the external dimensions of the brick chimney, and then calculate and sketch the pattern, as shown in the drawing. Formulas for determining the length of the sides of the elements depending on the initial dimensions of the pipe and the height of the wind vane are also given here.

Advice. The lower part, surrounding the mouth of the smoke channel, is best made in the form of a Z-shaped profile with angles of 90°, which will subsequently “sit” on top of the head. These profiles are then connected into a single frame using rivets.

Assembling the frame and installing the racks in the corners

The process of assembling a cap with your own hands is quite simple - you need to cut the metal according to the drawing, bend it along the dashed lines and connect the parts with rivets. It is proposed to take ready-made corners made of painted metal with a thickness of 0.5-0.7 mm as rigid racks. How to assemble a gable weather vane and a canopy in the form of a cover with a pipe passage is clearly shown in the video:

Do I need a cap on the chimney pipe?

It seems obvious to many that a cap on the pipe is necessary.

The main task of the device is not limited to protecting the chimney from precipitation, dust and debris. The functions of the pipe umbrella include:

• protection from the so-called tipping the draft - blowing smoke back into the chimney in strong winds;
• protection against birds and small animals entering the chimney;
• extending the service life of brick or steel pipes;
• chimney decoration.

The main role of the cap is obvious - it protects the chimney from the penetration of atmospheric moisture into the heating system, which is extremely undesirable and negatively affects the operation of the boiler equipment.

But there are counterarguments against installing a cap:

• the design may interfere with the removal of smoke and combustion products from the chimney, being an obstacle in the way air flow;
• the cap can reduce draft in the pipe;
• Due to the presence of water vapor in the exhaust gases in winter, ice forms on the canopy, and combustion products do not come out, but return back through the pipe in a concentrated state, poisoning the air in the room.

A cap on the chimney pipe will not interfere, provided that it is correctly selected and installed taking into account the requirements of SNiP and safety regulations.

Although some modern types of chimneys provide special devices for removing moisture and condensation, installing a wind vane on the pipe will protect the chimney from clogging and birds from entering the pipe opening.

Important! A metal cap is not an eternal design. With constant exposure to high temperatures and acidic components in fuel combustion products, thin sheet steel quickly breaks down

Depending on the device, the pipe nozzle must be changed every few years.

Characteristics of deflectors

Purpose

An umbrella is installed on the chimney to enhance draft by deflecting air flows. Deflectors correct design prevent atmospheric phenomena from entering the chimney - snow, slanting rain (see).

The chimney canopy also prevents debris and birds from getting inside. To do this, a mesh is installed, which freely allows smoke to escape outside.

Basic functions

Thus, the chimney canopy performs the following functions:

• increased traction;
• increase in the efficiency of the chimney pipe (up to 20%);
• protection from snow, rain, debris;
• obstacle to destruction brickwork chimney.

Important! A chimney cap will provide good draft only when the chimney does not move straight, but has several turns. . Chimney cap design

Chimney cap design

• cover or umbrella;
• drip or outlet for water.

A cover or umbrella is designed to protect against atmospheric agents entering the chimney. The drip line or water outlet is designed to remove draining moisture from the top of the pipe, thereby reducing the formation of ice during the winter.

Materials used to make a weather vane

When planning to make a chimney cap with your own hands, you should use materials that are heat-resistant and corrosion-resistant. The specified characteristics have the following materials:

• galvanized iron;
• stainless steel;
• copper.

It is important to remember that chimney caps are located in hard-to-reach places. Based on this, it is necessary to choose a cap that is made of high-quality material and that, according to its characteristics, is resistant to various atmospheric phenomena. One of the most durable is a chimney cap made of copper.

How to make a fungus on a pipe with your own hands

Making a chimney cap yourself is not an easy task. If you do not have much experience in this area, you can first transfer the drawing to a sheet of cardboard, cut it out and think about ways of connecting and fastening. After the picture becomes more or less clear, you can cut out the metal parts and start assembling

It is very important to measure the chimney accurately and strictly adhere to the measured values ​​during manufacture.

Here is one of the drawings of a chimney in the form of a small pitched roof. The angle is determined by the formula indicated on the first sheet.

Drawing of a chimney cap

Drawing of a chimney cap

The procedure is as follows:

• Place the metal blank on the table face up, in the place indicated in the drawing, drill a hole with a diameter of 3.5 mm.
• Bend the part along all the dotted lines by 90 degrees. For this it is better to use a sheet bending machine. Then the lines will be clear, without dents. If there is no such device, you will have to use improvised means: fix a piece of corner on a workbench with the shelf up. To be able to bend the entire (or almost the entire) line at once, you can use a block.
• Bend the part along the lines “d”. The angle is determined experimentally: a solid cap should be obtained. The structure should be level, without distortions (put it on the table to check). If everything “comes together”, mark a point on the lower stiffening rib with a marker through the drilled hole, mark the future hole, then drill.
• Connect the cap and secure with a 3.2mm rivet.
• Fold everything along lines “a” and “b” so that the legs can be installed.
• Along the outer perimeter of the pipe, make the base of the cap from the corners. Place the corners so that one edge rests against the masonry, and the other is on the side. Prepare the “legs” for the cap. Everything is connected by welding.
• The finished base must be cleaned, coated with an anti-corrosion compound, then painted in several layers with paint for exterior use.
• Connect the cap to the base.

If making a square chimney seems difficult to you, maybe this option will be easier. Its implementation will be quite simple if you have a piece of curved sheet metal of the appropriate size. If you have a regular sheet, you can bend it using a special device (usually available from tinsmiths).

Do-it-yourself smoker

The procedure is as follows: prepare the base of the cap from the corner according to the measurements of your chimney. Place the corner so that the structure holds well: one edge rests on the edge of the chimney, the other covers it from the outside. Make legs that will support the cap and connect it to the base. Make them strong enough to withstand wind loads and withstand snow loads. Treat all parts with an anti-corrosion compound and paint. Assemble the structure into a single whole. The collection method depends on the material.

Here is an example of how to make a deflector for a metal pipe. The author of this video has it installed on a basement ventilation pipe, although a similar design can be used on metal pipe from a solid fuel boiler.

This video shows how to make a regular umbrella for a pipe.

You're always welcome)) How to attach the cap depends on the pipe material. Judging by the fact that the development is only for square or rectangular, you have a brick pipe. If so, you can attach the weather vane to dowels, and more often. And not into the seam, but only into the brick. If the winds are strong, you can make the lower part, which will be put on the pipe, wide and beat the fasteners not in one row, but in checkerboard pattern: top-bottom. If you didn’t guess with the material, unsubscribe.

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Making a cap with your own hands

The most common and universal option is a rectangular cap with four slopes. Such a product is easy to purchase, but you can make a simpler, but no less effective semicircular version with your own hands.

The semicircular smoke vent is simple and easy to use

To do this, you will need a sheet of galvanized metal with a thickness of 1 mm, rivets, and metal scissors. A set of devices complements the marker for marking. The dimensions of the structure are preliminarily determined and a life-size drawing is made on cardboard. You can make a drawing yourself or using it as a basis ready-made diagram and adjusting its parameters.

For a semicircular chimney, you can use a drawing of a pitched structure by changing the shape of the lid

The complex of works for the manufacture of a chimney involves the following stages:

1. A rectangle is cut out of a sheet of metal, which will become a semicircular roof of the chimney. To do this, transfer the drawing to the metal and cut out the element with scissors.

   Galvanized steel is easy to process

2. Strips are cut from the same metal, from which the frame will be assembled for attaching the cap to the pipe. The width of the strips should be about 10 cm, and the length depends on the size of the chimney.

   Metal strips or profiles allow you to make a frame for attaching the cap

3. The structure is assembled according to the drawing, fastening the frame and vertical posts with rivets or welding. Then they bend the rectangular sheet and fix it on both sides to the frame.

   The frame can have a stepped shape

Video: making a chimney

Making a cap for a chimney pipe with your own hands is not difficult, but precise determination of the product parameters is important. Quality materials are also the key to creating a durable structure

Making and installing a hood with your own hands

When assembling a simple model of a cap at home, you can do without special rolling machines, just simple tools and devices.

Required tools and materials

Set necessary tools for the manufacture and installation of a weather vane, it must consist of:

• metal ruler;
• marker;
• wedge-shaped mallet;
• metal scissors;
• electric drill;
• special clamp;
• sheet bender;
• mandrels;
• small hammer.

Materials you will need:

• sheet of cardboard;
• sheet metal;
• metal plate;
• screws;
• primer for metal;
• dye.

Drawings and diagrams

A simple cap made of galvanized sheet metal 0.6 - 0.8 mm thick for a square or rectangular brick pipe can be easily made with your own hands. It has a pyramid-shaped lid and is cut using a pattern from a single sheet of metal.

For chimneys and ventilation shafts round section use a TsAGI deflector. It is called so because it is an invention of the Central Aerodynamic Institute. It can be made from thin stainless steel or galvanized sheet.

You can also install a Grigorovich deflector on a round chimney.

Size calculation

The chimney must cover all planes at the end of the pipe, and if the design includes a head, then the cap must cover it too horizontal surfaces.

The future product should be quite easy to put on the pipe, so each of its length and width needs to be increased by 4-5 mm.

The wings must be of such a size that they cover the horizontal surfaces of the head.

Work progress

The process of assembling and installing the hood consists of the following steps:

• Making a pattern from cardboard according to the calculated dimensions.

• Transferring its contours to a sheet of metal and cutting out the umbrella blank using metal scissors.
• Place the workpiece on the workbench with the markings facing up, so that it is more convenient to bend first the lines marked with a dotted line in the drawing to a right angle, and then the lines marked with the letter “d”.
• Rolling a cone. The connection point must be secured with rivets.
• Making a dropper. The contours of the drip apron parts are drawn according to the pattern on a sheet of metal and cut out. Bends along the edges of the elements are made using a sheet bender. Rivets are also used to connect parts.

• Attaching the brackets. They must first be cut from metal plates, and then welded at one end to the apron and umbrella. To treat welding areas, use a metal primer.
• Cap finishing. All surfaces of the chimney are covered with 2 layers of paint, which will protect the metal from corrosion and give the product a more aesthetic appearance.
• Installation of the cap on the head of the smoke exhaust pipe. The mounting option for the product is selected depending on the type of pipe. In some cases, screws are used or an additional clamp is installed.

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. It was already installed by primitive people to avoid wind blowing into the chimney.

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 instructions from 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.

Stages of evolution of the smoke deflector from a simple umbrella to the TsAGI deflector

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.

How to make a chimney with your own hands

To make this element of protection yourself, a chimney design with a gable lid for a square or rectangular chimney is suitable. For work you will need the following materials and tools:

1. Sheet of metal for the roof.
2. 4 pieces of profile 20x20 mm.
3. Metal corner.
4. Tape measure, vice, hammer drill and metal scissors.

At the first stage, the pipe hole is measured and 5 mm is added to the result for a secure fit. Further it is necessary from metal corner weld the base for the visor. Sections of profile 50 cm long are welded at the corners of the structure, which will become a support for the roof.

Pattern diagram for making a chimney for a chimney

At a height of 20 cm, supports for the visor are welded. Their lower part should be lowered deep into the pipe by about three bricks, which will allow the entire structure to be securely fastened.

The chimney roof will be secured to the top of the supports, for which a steel sheet is bent in a vice at an angle of 900. This canopy is fixed to the posts with plates and rivets.

Making a chimney smoker with your own hands is not so difficult, the main thing is to fasten it securely so that the umbrella does not get torn off by the wind.

How to make a chimney with your own hands?

Design

A chimney cap is a device that resembles an umbrella or canopy in appearance and is installed on the head of the chimney to protect against moisture. There are a huge number of variations in the appearance of weather vanes, depending on the shape and size of the smoke exhaust duct. The design of all types of hoods consists of the following elements:

Chimney cap design

1. Protective umbrella. The top of the cap is in the form of a cone, pyramid, semicircle or other more complex shapes. The umbrella protects the chimney from precipitation, debris, and birds from entering the chimney.
2. Drip apron. This element of the cap protects the pipe head from drops bouncing off the umbrella. It helps to increase the service life of the chimney, prevents corrosion and fungus. The apron is used when a cap is installed on a rectangular or square pipe.

Brackets. Sheet metal plates that are used to connect the canopy to the apron. The number of brackets depends on the size of the chimney and the weight of the umbrella. Fastening is done by welding.

Important! For a chimney, you can make a cap yourself from sheet metal, however, more complex models are easier to buy or order. The most convenient type to maintain and operate is a protective umbrella with an opening lid.

Due to the mobility of this element, the protective visor is not removed during cleaning or inspection of the chimney.

To make a durable cap for the chimney pipe, sheet metal that is not subject to corrosion is used. DIY production from galvanized steel, copper or aluminum is common. An umbrella with a copper head has a noble shade, it looks respectable, but often becomes a “victim” of non-ferrous metal collectors.

How to close the top of a chimney of a complex device

The simplest and most technologically correct solution is to install a wide metal cap on such a chimney:

Another good option for protecting such a chimney from moisture and snow getting between the contours is to create a concrete cap:

Let us note that for many, such an option for completing a chimney seems surprising: why, when making a cap for a chimney, should you also make a screed at the exit? In fact, such a screed prevents sparks from entering the shaft, and rainwater flows exclusively onto the street.

Also suitable option– making such a cap wide enough to completely cover the entrance to the pipe:

Study our master classes, choose a suitable design and make a blank for the future object of your own pride!

Making a cap with your own hands

You can make a canopy for the chimney with my own hands, if you follow certain instructions. But it is worth remembering that in the absence of experience it is better to assemble a simple but effective design. To manufacture the described structure, it is necessary to purchase galvanized steel sheets. For work you will need tools such as metal scissors, welding machine, marker and bends.

You can make a cap for a chimney pipe with your own hands quite simply:

1. At the first stage, measurements are taken from the chimney.
2. Then a pattern of the future cardboard product is created. During work, you need to take into account that the umbrella should be put on the chimney easily, so a gap of approximately 4 mm is added to the dimensions of the pipe.
3. After this, the drawing is transferred from cardboard to metal using a marker. Using metal scissors, the umbrella blank is cut out.
4. At the next stage, the necessary elements are cut out from the metal plate, as well as the material is bent. In places where the edges will connect, it is necessary to make holes, the distance between which should be about 15 cm. After this, the visor is fixed with rivets.
5. Then the pattern of the drip apron is transferred to metal and cut out. During work, it is important to correctly cut the material to size so that the product effectively performs its functions.
6. Next, brackets are created from metal plates, which are then welded to the apron and umbrella. After completing such work, it is necessary to treat the welding areas with a metal primer.
7. On final stage Anti-corrosion coating and paint are applied. After this, you need to wait about 2 days for the coating to dry completely. This completes the creation of a chimney cap with your own hands.

When creating brackets, it is important to consider that in winter a large amount of snow falls on the cap, so the plates must be strong enough. .

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Oddly enough, first of all, the choice of hood depends on the type of boiler installation and the type of fuel burned. For example, nozzles on chimneys serving gas boilers can be installed in only one design - in the form of a nozzle, with an open top.

Important! Regulatory documents of the Russian Federation and Ukraine strictly prohibit the installation of all kinds of umbrellas on the chimneys of all gas-using installations

Perhaps similar restrictions exist in regulatory frameworks other countries, so you should pay attention to this before purchasing the attachment to avoid trouble.

Open top nozzle

Such prohibitions are explained very simply. At negative temperatures, the chimney cap will begin to freeze and become covered with a layer of ice. The latter will gradually block most of the working opening, the smoke will have nowhere to go, and the draft will sharply decrease. The result is that fumes go inside the house, and people’s lives are in serious danger. Below is a photo where the icy umbrella is clearly visible:

Icy chimney umbrella

The reason is condensation that forms on cold metal upon contact with low-temperature combustion products. This is the temperature of smoke from boiler plants with high efficiency, that is, gas ones. Because of this, it is prohibited to place a cap on a brick chimney pipe. It’s another matter when the boiler is solid fuel, its efficiency varies between 70-80%, and the outlet gas temperature ranges from 150 to 250 ºС. Here you can safely select a nozzle, especially for a brick channel that is destroyed by precipitation. Just remember that it will quickly become covered with black soot.

Note. Pellet boilers running on high-quality fuel can also achieve an efficiency of about 90%, so it’s better not to risk it and use an open nozzle as a canopy on the pipe.

When the issue of boiler installations is clarified, let’s move on to the gas exhaust pipe itself. The easiest way is if it is assembled from a three-layer modular sandwich, then protecting the chimney from rain is not required at all. The ingress of precipitation into the channel even benefits it; the pipe is washed from the inside, and then the water is discharged into the condensate collector. For a gas boiler we choose a nozzle, for a solid fuel boiler - any other nozzle, preferably from a technical point of view - a deflector-vane.

What about a brick pipe? No problem, when it serves a solid fuel boiler, you can choose a cap from any material and any shape you want, according to your means. If the combustion products are removed from the gas boiler through the channel, then the umbrella cannot be placed on the chimney pipe at all, and the constant entry of moisture into the channel destroys the material. Nevertheless, there is a way out of this situation; to be convinced of this, just look at the photo:

Chimney protection box

Here you can clearly see that the cap is made as a protective box that completely covers the brick base. Since the photo shows a pipe with several channels, some of which are ventilation, the pipes and umbrellas used are different. But nozzles are installed on the chimney ducts in accordance with the standards.

When choosing a hood design, you should take into account what material the chimney pipe is made of and the type of fuel used to operate the heating device.

This is due to different temperatures flue gases and heater efficiency:

• for a brick stove with a chimney of square or rectangular cross-section, also made of brick, a special cap - a deflector - is suitable. A feature of chimneys of this shape is the danger of the formation of vortices, which impair draft. In addition, more soot, soot and dust are deposited on the rough surfaces of the brickwork, narrowing the lumen of the pipe, which can greatly impair traction, even to a complete stop. The deflector will protect the chimney walls from excess moisture, thereby reducing the adhesion of combustion products and acting as a draft amplifier. It will create a vacuum in the upper part of the channel and promote the outflow of air from the firebox;
• Solid fuel boilers are usually equipped with ceramic pipes or chimneys made of “sandwich” pipes with a double wall. They have a smoother surface than brick structures and are equipped with a condensate collector into which condensate and precipitation drain, so they have much less soot deposits on the inner walls. The draft stability of such boilers depends on the height of the chimney. If you do not organize forced draft, then you need to install a very high pipe (up to 8 m). When installing a deflector, the height of the chimney can be reduced by 15-25%, while the stability and draft force will remain at the same level, and installation of the reduced pipe structure will be less complicated. If you have a boiler whose operation is based on the principle of pyrolysis, it is better to install a cap with an open nozzle on the chimney pipe. It will be able to protect the channel from debris and precipitation, but will not become a barrier to the exit of low-temperature smoke;
• For gas and diesel boilers, it is also recommended to use a hood with an open nozzle. In them, the draft is forced, so there is no need to increase the draft with the help of a smoke deflector.

Grigorovich deflector

Another time-tested design - Grigorovich deflector. which installed on chimneys of round cross-section to stabilize draft. The Grigorovich deflector consists of several parts:

• deflector in the shape of a truncated cone;
• a cap that protects the pipe from precipitation;
• a reverse cone that creates an area of ​​reduced pressure under the hood and improves traction.

The Grigorovich deflector can be made from the same materials as the above models; their manufacturing technology is generally similar. Dimensions are determined based on the diameter of the pipe. It is taken as a basis and, using the coefficients, the remaining dimensions are calculated:

• The diameter of the cone-shaped diffuser in the lower part is taken to be 2d, in the upper part - 1.5d, the height of the truncated cone - 1.5d.
• The cone-shaped umbrella cap and the return cap have a diameter of 2d and a height of 0.25d.
• The distance from the top of the return hood to the top edge of the diffuser is also 0.25d.
• The distance from the top edge of the pipe to the bottom edge of the diffuser is 0.15-0.2d.

The last two sizes are provided with brackets of the required height, which are made from scraps of tin and secured with rivets, bolts or by welding.

Manufacturing and installation technology:

1. Based on the calculated dimensions, a sketch is made, transferred to sheet metal and the elements are cut with metal scissors.
2. The cones are bent on a mandrel and the edges are fastened with rivets or by bending. The umbrella and the reverse cone are connected in the same way.
3. Using brackets, the parts are fastened together, maintaining the calculated distances.
4. Attach the deflector to the pipe. To facilitate its installation, the deflector can be equipped with a lower cylinder, the diameter of which allows it to be pressed onto the pipe.

The service life of a cap or deflector made of stainless steel is 25 years, from galvanized steel - at least 10 years. To extend it and give galvanization an attractive look, you can coat it with black heat-resistant paint from a can. In this case, soot and soot will not be visible on the cap.

Install the cap on chimney quite simple, and the benefits of it are obvious - you no longer have to heating season spend time cleaning the pipe from leaves, fluff, and dust. Precipitation will not get into the pipe, which will allow it to be used without corrosion or destruction of the brick. Installation of the deflector, in addition, will make the draft stable even with a small pipe height, regardless of weather conditions.

Roof and roof repair

What materials are used to make caps and fasteners?

Chimney caps are made from materials that are resistant to corrosion, withstand high temperatures and have a long service life. The temperature requirement applies only if the device will be closing the chimney. For ventilation ducts, a product made of polyester, pural, etc. is quite suitable. In all other cases use:

• Galvanized steel
• Stainless steel
• Zinc-titanium alloy

Copper weathercocks (smoke boxes) last a long time, from 50 to 100 years. This is one of the most durable materials, but when installing it, it is necessary to use copper hardware. Otherwise, active corrosion processes will begin, which will significantly shorten the life of the device. The installation of a zinc-titanium cap on a chimney requires, for the same reasons, the use of only galvanized hardware. Zinc-titanium is a new alloy that has recently been used only for the manufacture of roofing materials, but today many companies have begun to produce chimney caps from it. They have a half-century warranty and a much lower price than copper ones. You can install caps made of other materials on the pipe using ordinary hardware, although it is still better to take those that are not susceptible to oxidation and destruction: most weather vanes can serve for decades, but climbing onto the roof because it was torn off by the wind due to a broken fastening is not the best have a nice time. If we talk about a brick pipe, then you can use either ordinary long nails or threaded ones (but it is almost impossible to dismantle them), you can use dowels. In each specific case, the fastening system is selected based on the shape and material of the pipe, available holes for fastening, etc.

Forged chimney caps

The most popular type of this product is a stainless steel chimney with or without a polymer coating. The service life in this case is 20 years, but the price is much lower. The option with a polymer coating is especially popular - the color can be matched to the color of the roof, and if the design is in the style of the roof, this option looks great.

Weather vanes

Deflectors for pipes - 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. Weak point all weather vane deflectors - 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-bladed 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

Material of manufacture

When choosing a chimney for your home, you need to focus on the desired set of functions

It is also worth paying attention to the service life and operating conditions.

From copper

Such models are considered the most durable, and their appearance is one of the most beautiful. Installation of copper chimneys must be carried out in accordance with strict rules, otherwise they will not last long. The main problem is that copper can react with other metals, leading to negative consequences. For example, the destruction of a copper chimney.

According to all of the above, installation of copper products must be done using copper or copper-plated fastening elements. Copper has a fairly long service life, over fifty years. High-quality installation work will only contribute to its increase. Over time, copper products become covered with a patina, which gives them special kind and the charm characteristic of antiques.

Made of steel

In terms of durability, such models are almost five times inferior to copper ones. Made from galvanized steel, they will last up to thirty years.

Made from zinc titanium

This modern material for roofing work is becoming increasingly popular. The characteristics of zinc-titanium products are comparable to those of copper, and their durability can exceed fifty years.

Design Features

The weather vane can have a round or rectangular shape and consists of several elements: a bandage that is worn over the chimney, support posts and a canopy or roof. The material used for making chimneys is metal or metal alloys.

For the production of smoke hoods, the most common is black steel, which is coated with a layer of zinc or painted with heat-resistant paint to protect against corrosion. To increase the service life, wind vanes on the chimney pipe are made of copper or stainless steel, the time of use of which is not limited in time. Over time, such construction materials will darken and will not look so elegant, but they will fully perform their protective functions. Such a structure, made by professionals and taking into account the laws of aerodynamics, will not allow the street air flow to blow into the channel and create a counter passage for exhaust gases. The slotted design makes an analogue of the wind deflector rings, which increase the vacuum during the passage of outside air, thereby organizing additional traction.

The weathervane caps on the roof also act as an artistic component of the overall appearance of the house. They are made in the form of various famous buildings, contain figurines of popular movie characters, cartoons, mythical birds, animals, recognizable silhouettes of ships and are an additional decoration for the appearance of the building.

Step-by-step instructions for making a simple cap

Initial data: stainless steel chimney pipe Ø 120 mm, solid fuel boiler, cap made of galvanized sheet steel 0.45 mm thick and painted with polymer paint.

Stainless steel chimney pipe

We will consider the simplest, but very effective option cap It can be done at home without the use of special tools and equipment available from professional tinsmiths.

Step 1. Decide on the diameter of the cap. Practitioners recommend that its edges protrude beyond the perimeter of the pipe by at least 10 cm on each side. Using this value, you can find out the diameter of the circle that needs to be cut out of metal.

A circle is drawn on a sheet of metal

Calculations are made this way.

1. Add the amount of cap overhang on each side to the pipe diameter. In our case, the pipe diameter is 120 mm, add 200 mm to this value (100 mm + 100 mm), we get 320 mm.
2. Now this amount needs to be increased by another 50 mm. This increase is required to compensate for the reduction in size due to the bend of the cap. The fact is that it will have the shape of a cone, and when bent, the diameter of the flat circle decreases. In our case, to make a cap, we need to cut out a circle with a radius of (320+50):2=185 mm.

Of course, these are not real mathematical calculations; they are much more complex. But for the cap there is no need to accurately calculate all the dimensions; tolerances of a few centimeters do not play any role.

Practical advice. You can cut a circle to fit a cone immediately, removing the segment for the bend. To do this, you need to draw lines 6 cm long from the radius in both directions, draw lines from the points of intersection with the circle to the center and cut out the resulting circle segment.

Drawing metal with bending allowance

If you want to make a simpler cone design, then do not cut out the segment, but only cut a vertical line to the center of the circle. During bending, the excess metal will overlap; in this place it is convenient to drill holes and place rivets.

Step 2. Using hand metal scissors, cut out the workpiece and remove the wedge from the circle.

Cut blank

Step 3. Make special folds on both sides of the workpiece to secure the cone. This should be done in cases where rivets will not be used to secure the cone. Hems must be made with a hammer.

Bends for fixing the cone are made with a hammer

Height is approximately 0.5 cm, twisted in opposite directions. Do not squeeze the folds all the way, this is done finishing stage making a cone. If it is difficult to work with a mallet, then you can bend the metal with ordinary pliers. The line won't be as smooth, but that doesn't matter. The cap is installed very high on the chimney; from the ground, such minor problems are completely invisible.

You can bend metal using pliers

Step 4. Bend the cone and inspect the connection. If any parts interfere with fixation, they should be bent or cut off. The lock must operate clearly along the entire length of the cap.

Bent Cone

Step 5. Shape the cap. To do this, it needs to be gradually bent using the so-called straightening. This is a piece of pipe with a diameter of ≈ 50 mm, fixed in a vice. Gradually bend the circle until it takes the shape of a cone. Constantly check the product, do not bend it too much.

Bending the cap

Step 6. Connect the lock and rivet it. Try to keep the line as straight as possible.

You can rivet a castle with a mallet

At this point, the most difficult stage of making the cap is completed, you can begin preparing the legs for fixing it. First, the legs themselves are made; for them it is necessary to have three strips of metal approximately 2 cm wide and up to 15 cm long. To give the legs greater rigidity, a fold should be made along the edges.

Folds are made on the legs - fold

Leg making, process

The cap is fixed to the pipe with a clamp. You can buy it ready-made in a special store or make it yourself. The second option will require more time, but the design has a finished design in the same style.

The last stage is to mark the places where the legs are attached to the cap, drill holes and secure the elements. It is better to use rivets for fastening. The lower end of the legs is attached to the clamp using the same hardware. Now all that remains is to secure the cap to the chimney pipe.

Attaching the legs

Attaching the ring to the legs

Cap on the pipe

Fixing the cap ring

Is it worth installing

This is a question many owners of private buildings ask. Arguments for and against can always be found for every subject.

Let's consider positive aspects settings:

• reduces the possibility of fire extinction due to wind blowing it out;
• the pipe is protected from debris brought by the wind;
• precipitation will not be able to penetrate under the chimney;

• the mesh design reliably excludes the chimney from possible bird nesting areas;
• the pipe head, protected from precipitation, will last longer;
• decorative elements will be an excellent decoration.

Professionals argue that information provided by advertising, such as increased traction and efficiency, is not reliable.

The disadvantages of installing chimneys include the following:

• the hood visor can become an obstacle to combustion products, preventing them from escaping. It follows that, contrary to advertising, it reduces cravings.
• water vapor from high-efficiency boilers has a temperature of up to 120 degrees. In contact with cold metal, it condenses on the chimney, which in the cold season can lead to the formation of icicles. Which, in turn, can lead to disastrous consequences, because ice blocks air circulation.
• modern round chimneys are built taking into account the impossibility of birds building a nest.
• A pipe built according to the rules must have a condensate collector.
• galvanized chimneys installed above solid fuel heating devices burn out within three to five years. To prevent this from happening, we need more expensive stainless steel analogues.

How does a chimney pipe cap work?

• Lid.
• Net.
• A drain of water or otherwise called a drip.
• The angle of inclination of the roof should be 45 - 50 degrees, but you can make the inclination angle larger or smaller, or make the height of the lid.
• The net will make it possible for birds not to settle and make nests. This will solve many problems in the future.
• The cover is designed to prevent precipitation from entering the pipe.
• The water drain or drip is designed to allow water to flow down from the hood.

Operating principles of a chimney cap

1. Does not allow water to drain.
2. Prevents ice from forming, which contributes to the durability of the masonry and the entire structure as a whole.
3. Air flows they hit the walls and go around from all sides.
4. Air jet picks up the smoke and lifts it higher.
5. Because that the air moves, it becomes stronger and the thrust becomes greater.
6. If the chimney is made by professionals, then this will easily allow the house to remain warm when you heat the house.

What may be on the weather vane

• Net.
• Skirt.
• Spark arrestor.

The size of the weather vane depending on the diameter of the chimney

Pipe height (mm)	Pipe width(mm)	Diameter (mm)
145	245	120
170	285	145
250	430	210
500	840	420
658	1100	520

Classification of visors by shape

• In the form of a tent.
• Four-slope visor.
• Gable visor.
• In the form of a flat sheet.
• In the form of a spire.
• Vaulted canopy.
• In the form of four forceps.
• The visor is in the form of a flat sheet, made of copper sheet. They do it on houses in the Art Nouveau style.
• If the house is built, as in Europe, then a semicircular canopy is installed on such a house.
• When installing a four-gable canopy, the chimney will not fill with snow.

Classification of visors by metal type

The service life of the visor depends on the material

You should pay attention to the material from which it is made. Since the visor is in an inaccessible place, there is no way to constantly monitor it. If the cap does not withstand weather conditions, the system will not operate stably.

1. The most popular materials are copper alloys and copper itself.. Copper canopies are the most reliable. At correct installation visor made of copper, the visor will last 70 years.
2. In second place is galvanized iron steel. In terms of durability quality, it is on par with copper and copper alloys.
3. In third place are visors made of steel sheets. They are inferior to copper in terms of operating time. They will last about 40 years.
4. Iron made of stainless steel.
5. Alloys made of titanium and titanium itself. They have proven themselves well. Durability is guaranteed, soft, durable.

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 the materials are not very difficult work it takes a little.

What can an umbrella do?

In the climatic conditions of the Russian Federation, a deflector-umbrella on a chimney is most often sufficient, especially since there was no evidence of waste caused by it either. 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.

Dimensions of deflectors-umbrellas for chimneys and ventilation.

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.:

Modifications of the deflector-umbrella for the chimney and ventilation pipe

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. The upper floor is gabled, 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 we take on the aerodynamically open deflector, let’s see how the most advanced TsAGI deflector is modified for a private home. Its original design was designed primarily for industrial facilities and then for apartment buildings.

Drawings of 3 versions of the TsAGI deflector are shown in Fig. The dimensions of the original 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 gives less horizontal wind load and it can be inserted into the pipe as described below.

Modifications of the TsAGI deflector for chimneys and ventilation pipes

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: a ventilation deflector is 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, it’s stuffy in the bathroom and kitchen.

What comes out of cones

From deflectors open type The Volpert-Grigorovich deflector is the most accessible and, based on the entire range of technical indicators, 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:

Proportions and dimensions of the Volpert-Grigorovich deflector for the chimney

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

Smoker weather vane

A type of smokehouse is a weather vane, which is mechanism for attaching to the chimney and the main body.

This type of element protects from rain and snow falling into the chimney, helps to increase the draft of air masses, and protects the roofing well from damage by sparks.

The top of the entire structure of the weather vane is made in the form of an inclined flat element, its area is larger than the cross-section of the chimney itself.

The plate covers the chimney, and the side structural elements form a gap between its bottom edge and the air duct.

The weather vane has a rotating body that is mounted on a rod. The rod is mounted on a special bushing. The sleeve has a connection with a cylinder-shaped base, which, in turn, is equipped with a flange.

Operating principle

The functioning of the weather vane consists of the rotation of its moving upper part, which rotates along an axial guide along the air flow. Due to the fact that the air flow envelops the very top of the weather vane, it turns.

As a result, a rarefaction of the air flow occurs between the chimney outlet and the weather vane itself. This increases the air draft from the chimney.

Operating principle

The weather vane can be presented in various designs: in the form of eagle heads or dragons, a stork or a falcon. The variety of forms of such elements allows you to complement the architectural ensemble of the building with an appropriate solution for choosing an additional element.

Chimney umbrella pros and cons

The following arguments speak in favor of installing various caps (vanes) on chimney heads:

• the umbrella partially covers the mouth from being blown in by the wind and thus reduces the likelihood of the draft overturning;
• the chimney serves as protection against the ingress of debris and moisture in the form of precipitation;
• if you use a mesh structure, then birds will not be able to nest inside the chimney;
• the product extends the service life of the head of a brick pipe, which is destroyed by wind, rain and snow;
• a weather vane with decorative elements complements the architectural style of the building.

Variant of weather vane with bird net

Note

When compiling the list, we did not take into account false advertising information. Claims that various nozzles increase draft in gas ducts and increase the efficiency of boilers are pure fiction

Now let's look at the counterarguments. The main negative point is that the chimney cap in the form of a fungus stands in the way of combustion products, that is, it prevents their free exit, creating noticeable aerodynamic drag. This means that the chimney umbrella does not increase draft, but, on the contrary, reduces it.

The second disadvantage of using attachments has been repeatedly confirmed by sad statistics. The fact is that one of the products of combustion of hydrocarbons is water vapor, which escapes into the atmosphere along with smoke. In diesel and gas boilers with high efficiency, exhaust gases with temperatures up to 120 ° C are cooled as they rise through the pipe, and then come into contact with the metal of the cap.

Examples of icing on chimneys equipped with nozzles

The water vapor immediately condenses and freezes at sub-zero temperatures, causing icicles to form on the umbrella, blocking the cross-section of the chimney, as shown in the photo. As a result, fumes enter the room and poison the residents of the house. There are other arguments against installing fungi:

1. In modern round chimneys there is no place for birds to live, so there is no need to cover them with a net.
2. A properly constructed flue channel has a condensate collector at the bottom with a drain, where water that has entered the pipe in the form of precipitation will safely drain.
3. Thin galvanized caps installed on chimneys of solid fuel boilers and stoves burn out within 3-5 years due to constant contact with high temperature gases (150-200 °C). It is necessary to install a stainless steel reflector, which increases the price of the product.

Good afternoon, dear reader! To vent the mixture of gas and fuel combustion products outside, stoves, fireplaces and boilers must be equipped with smoke exhaust ducts. Their head is covered with a special visor or umbrella. At first glance, these products seem to be only decorative elements. But in fact, the cap on the chimney pipe performs a very important function in the chimney system. It can significantly increase the energy efficiency of the heating system as a whole, and also eliminate any risk of smoke in the home.

The cap is metal structure outwardly similar to an open umbrella, canopy or canopy, which is installed on the head of the chimney duct to protect it from precipitation, debris and birds.

Cap device

The classic cap model is assembled from several parts:

• - in the shape of a pyramid, cone, mushroom, hemisphere or other, more complex configuration. It performs the function of protecting the pipe from moisture and foreign objects;
• apron - drip. This part of the cap serves to protect the head of the chimney from drops flying from the umbrella. It helps to increase the service life of the chimney, prevents destruction of brickwork and corrosion metal parts, the appearance of dampness and fungal deposits on the surface of the pipes;
• brackets - metal plates used to connect the canopy to the apron. Their number is selected depending on the size of the chimney and the weight of the umbrella. The welding method is used to fasten products.

Operating principle

Installing a cap on the chimney will not only protect against water and debris getting into the chimney pipe, but also allows you to optimize the draft in heating device. This happens as follows:

• the air flow rests against the wall of the upper cylinder and is forced to go around it from all sides;
• sliding along the surface of the cylinder, the air stream turns upward, at this time the smoke coming out of the channel is sucked in;
• the air movement inside the chimney becomes more intense, a zone with reduced pressure is created at the top of the chimney, where smoke from the combustion chamber rushes;
• if the wind jets are directed vertically or at an angle, then they penetrate into the upper cylinder through the gap and suck gaseous combustion products into the pipe.

Advantages and Disadvantages

The advantage of installing a cap on the chimney is:

• more aesthetic appearance of the chimney duct;
• protection internal space pipes from getting hit foreign objects and various garbage;
• protection of the chimney material from the effects of precipitation;
• the chimney covers part of the mouth, preventing the wind from overturning the draft.

There are not many disadvantages to installing an umbrella on a chimney, but they are quite significant:

• the product is installed in the path of combustion products exiting and serves as some obstacle to their free outflow. An incorrectly selected and installed model can reduce draft and lead to smoke in the room;
• The water vapor generated during fuel combustion exits along with the smoke through the pipe to the street and condenses, coming into contact with the cold metal of the cap, and then freezes when the temperature drops below 0º. As a result, icicles freeze on the chimney, blocking the passage opening of the pipe and preventing the smoke removal process.

Types and designs of caps

The variety of shapes and types of smoke exhaust ducts forces manufacturers to develop hoods of any size, configuration, and appearance. IN specialized stores You can buy a chimney of the following shapes:

• gable;
• hip;
• tent;
• spire-shaped;
• with a flat lid.

Photo different types chimney caps:

For the manufacture of caps, one of the following materials is used:

• stainless steel;
• copper alloy;
• roofing galvanized sheet;
• galvanized steel with powder coating;
• titanium and zinc alloy.

The chimney design may have:

• an opening lid, which greatly simplifies chimney maintenance;
• ventilation hole providing free exit for combustion products;
• spark arrester - designed for solid fuel stoves that heat houses with roofing made of flammable materials.

Often smokehouses are equipped with weather vanes in the form of heraldic symbols or stylized as images of animals, birds, heroes of fairy tales, myths, and decorated with forging and carvings.

Make it yourself or buy it

A standard weather vane that looks like a house with hipped roof, you can make it yourself from galvanized steel. It is easy to cut and bend using simple tools.

If you do not have any skills and tools for the manufacture of such metal structures, then you can buy a ready-made device that is in harmony in style with the overall appearance of the roof.

The approximate price of the simplest cap model starts from 1100 rubles. The cost of TsAGI, Volpert-Grigorovich or Khanzhenkov galvanized deflectors does not exceed 3,500 rubles.

A rotary model made of stainless steel will cost much more - from 8,000 rubles. Well, the most expensive ones are exclusive forged products.

When choosing a hood design, you should take into account what material the chimney pipe is made of and the type of fuel used to operate the heating device.

This is due to different flue gas temperatures and heater efficiency:

• for a brick stove with a chimney of square or rectangular cross-section, also made of brick, a special cap - a deflector - is suitable. A feature of chimneys of this shape is the danger of the formation of vortices, which impair draft. In addition, more soot, soot and dust are deposited on the rough surfaces of the brickwork, narrowing the lumen of the pipe, which can greatly impair traction, even to a complete stop. The deflector will protect the chimney walls from excess moisture, thereby reducing the adhesion of combustion products and acting as a draft amplifier. It will create a vacuum in the upper part of the channel and promote the outflow of air from the firebox;
• Solid fuel boilers are usually equipped with ceramic pipes or chimneys made of “sandwich” pipes with a double wall. They have a smoother surface than brick structures and are equipped with a condensate collector into which condensate and precipitation drain, so they have much less soot deposits on the inner walls. The draft stability of such boilers depends on the height of the chimney. If you do not organize forced draft, then you need to install a very high pipe (up to 8 m). When installing a deflector, the height of the chimney can be reduced by 15-25%, while the stability and draft force will remain at the same level, and installation of the reduced pipe structure will be less complicated. If you have a boiler whose operation is based on the principle of pyrolysis, it is better to install a cap with an open nozzle on the chimney pipe. It will be able to protect the channel from debris and precipitation, but will not become a barrier to the exit of low-temperature smoke;
• For gas and diesel boilers, it is also recommended to use a hood with an open nozzle. In them, the draft is forced, so there is no need to use a smoke vent - a deflector.

Making and installing a hood with your own hands

When assembling a simple model of a cap at home, you can do without special rolling machines, just simple tools and devices.

Required tools and materials

The set of necessary tools for the manufacture and installation of a weather vane should consist of:

• metal ruler;
• marker;
• wedge-shaped mallet;
• metal scissors;
• electric drill;
• special clamp;
• sheet bender;
• mandrels;
• small hammer.

Materials you will need:

• sheet of cardboard;
• sheet metal;
• metal plate;
• screws;
• primer for metal;
• dye.

Drawings and diagrams

A simple cap made of galvanized sheet metal 0.6 - 0.8 mm thick for a square or rectangular brick pipe can be easily made with your own hands. It has a pyramid-shaped lid and is cut using a pattern from a single sheet of metal.

For chimneys and ventilation shafts of circular cross-section, a TsAGI deflector is used. It is called so because it is an invention of the Central Aerodynamic Institute. It can be made from thin stainless steel or galvanized sheet.

Size calculation

The chimney must cover all planes at the end of the pipe, and if the design includes a head, then the cap must also cover its horizontal surfaces.

The future product should be quite easy to put on the pipe, so each of its length and width needs to be increased by 4-5 mm.

The wings must be of such a size that they cover the horizontal surfaces of the head.

Work progress

The process of assembling and installing the hood consists of the following steps:

• Making a pattern from cardboard according to the calculated dimensions.

• Transferring its contours to a sheet of metal and cutting out the umbrella blank using metal scissors.
• Place the workpiece on the workbench with the markings facing up, so that it is more convenient to bend first the lines marked with a dotted line in the drawing to a right angle, and then the lines marked with the letter “d”.
• Rolling a cone. The connection point must be secured with rivets.
• Making a dropper. The contours of the apron-drip parts are drawn according to the pattern on a sheet of metal and cut out. Bends along the edges of the elements are made using a sheet bender. Rivets are also used to connect parts.

• Attaching the brackets. They must first be cut from metal plates, and then welded at one end to the apron and umbrella. To treat welding areas, use a metal primer.
• Cap finishing. All surfaces of the chimney are covered with 2 layers of paint, which will protect the metal from corrosion and give the product a more aesthetic appearance.
• Installation of the cap on the head of the smoke exhaust pipe. The mounting option for the product is selected depending on the type of pipe. In some cases, screws are used or an additional clamp is installed.

Installation video

The technology for making a round umbrella is clearly demonstrated in the video.

Boiler room or stove heating the house requires the installation of a chimney, which in most cases leads to the roof. An essential part of the chimney pipe is the cap, which is installed at the end of the chimney. It is also called an umbrella, a visor, a weather vane or a lid, which may have different shape, size and design.

IN construction stores They sell ready-made products made of galvanized steel sheets, which can be immediately installed on the chimney head. But anyone with minimal skills in working with metal can make a pipe cap on their own.

It seems obvious to many that a cap on the pipe is necessary.

The main task of the device is not limited to protecting the chimney from precipitation, dust and debris. The functions of the pipe umbrella include:

• protection from the so-called tipping the draft - blowing smoke back into the chimney in strong winds;
• protection against birds and small animals entering the chimney;
• extending the service life of brick or steel pipes;
• chimney decoration.

The main role of the cap is obvious - it protects the chimney from the penetration of atmospheric moisture into the heating system, which is extremely undesirable and negatively affects the operation of the boiler equipment.

But there are counterarguments against installing a cap:

• the design may interfere with the removal of smoke and combustion products from the chimney, being an obstacle to the air flow;
• the cap can reduce draft in the pipe;
• Due to the presence of water vapor in the exhaust gases in winter, ice forms on the canopy, and combustion products do not come out, but return back through the pipe in a concentrated state, poisoning the air in the room.

A cap on the chimney pipe will not interfere, provided that it is correctly selected and installed taking into account the requirements of SNiP and safety regulations.

The chimney design will be incomplete and ineffective without a special cap, which is an external element. There are different options caps, differing in a complex of features. To ensure maximum functionality of the chimney, it is important to choose a suitable design.

Purpose and functions of the chimney cap

The cap on the outer part of the chimney pipe is a rather important element that performs several functions at once. A correctly selected pipe part complements the appearance of the building well, emphasizing the design style. At the same time, the cap has compact dimensions, is easy to install and increases the efficiency of the chimney.

A chimney cap can become an original decoration for the roof of a residential building

The chimney cap is made of metal, as this material ensures the strength and durability of the product. The simple design performs the following functions:

• protection of the inside of the chimney from moisture, debris and dust;
• increased draft in the pipe for efficient combustion of fuel in the furnace;
• aesthetic addition to the building design;
• extending the life of the chimney as a result of its protection from precipitation.

A rectangular or square shaped cap is the most common option. This element provides effective draft and complements the chimney design well from an aesthetic point of view.

Materials for the chimney

The cap is located outside the chimney and is exposed to climatic factors and ultraviolet rays. Therefore, for the manufacture of the chimney, only high-quality, durable, resistant to various factors materials are used.

Metal is a practical basis for a chimney

To make a cap, various types of metals are used, each of which has different properties and characteristics. The main options are:

• sheet steel;
• sheet aluminum;
• rolled copper metal;
• stainless steel in sheets;
• zinc - titanium alloy.

Depending on the material that served as the basis for the cap, the characteristics of the product differ. For example, the service life of steel chimneys is about 5 years, and models made of sheet aluminum can be used for 8 years. The most durable caps are made of stainless steel, zinc-titanium alloy and copper, the service life of which reaches 50–100 years.

Design options

There are many options for chimney caps, differing appearance. Moreover, the design of all types of products includes a base, an upper roof and vertical posts. This cap is simple and protects the chimney well from precipitation. More complex options are deflectors, one of the main functions of which is to enhance traction.

Deflectors are varied and can be either simple or more complex.

Among the most popular smoke vent options, the following are especially noteworthy:

• cap with opening lid;
• flat chimney for pipe;
• cap with weather vane;
• cap of multi-slope design;
• deflector with ventilation holes.

The choice of a specific option is made depending on the type of roof, the design of the house, the shape and design of the chimney. For example, for metal round pipe metal deflectors are optimal, providing enhanced traction.

Photo gallery: types of chimney caps

A cap with forged twisted elements looks beautiful and complements the design of the house well. A weather vane on a pointed cap is practical and nice option design Multi-slope chimney provides good draft Even a large chimney cap can be decorated with forged parts A simple deflector is compact The dome-shaped shape is suitable for a chimney cap The weather vane on a large cap of a wide pipe looks beautiful and emphasizes the uniqueness of the building

Choosing a hood depending on the chimney

The correct choice of a chimney cap is the key to effective heating of rooms in the house and the absence of chimney breakdowns. The choice of chimney type is made depending on the type of pipe and heating system. For example, for the chimney of a gas boiler, only elements in the form of a nozzle with an open top are used. This model eliminates the possibility of ice covering the entire surface of the hood during the winter season.

Products in the form of a pipe are optimal for gas system heating

For brick outlets, multi-slope, rectangular or square elements are often used. Precipitation does not accumulate on the surface of such caps and therefore the chimneys are not subject to significant load. The shape of the deflector is selected depending on personal preferences and the design of the building. Many cap options can be easily complemented with a forged weather vane or twisted elements.

Making a cap with your own hands

The most common and universal option is a rectangular cap with four slopes. Such a product is easy to purchase, but you can make a simpler, but no less effective semicircular version with your own hands.

The semicircular smoke vent is simple and easy to use

To do this, you will need a sheet of galvanized metal with a thickness of 1 mm, rivets, and metal scissors. A set of devices complements the marker for marking. The dimensions of the structure are preliminarily determined and a life-size drawing is made on cardboard. You can make a drawing yourself or take a ready-made diagram as a basis and adjust its parameters.

For a semicircular chimney, you can use a drawing of a pitched structure by changing the shape of the lid

The complex of works for the manufacture of a chimney involves the following stages:

Video: making a chimney

Making a cap for a chimney pipe with your own hands is not difficult, but precise determination of the product parameters is important. High-quality materials are also the key to creating a durable structure.