Chimney damper: what is it, what is it for, types of dampers, how to make and install a damper with your own hands

What is it and what is it for?

Damper (from the German Schieber - damper) is a device for completely or partially blocking the movement of gases in the chimney. It has been used since the appearance of the first Russian stoves. Made from cast iron or steel. In modern engineering it has found application both in smoke exhaust structures and in ventilation systems.

Damper functions:

• Regulating draft and maintaining heat in the room.

The chimney is closed after use to prevent warm air from being drawn from the room into the chimney. Using a damper, you can reduce or increase the working cross-section of the chimney.

• Saving fuel consumption.

The valve can be used to regulate the intensity of oxygen flow to the flame, and accordingly increase or decrease the efficiency of the heater.

This statement is true only for furnaces and boilers without blowers and forced air supply devices.

Functions, purpose and characteristics

The damper is a partition that is located inside the chimney. It follows the shape and area of ​​its cross-section and, when closed, almost completely covers it. Changing the position of the damper allows you to increase or decrease the opening of the chimney pipe, increasing or decreasing the air flow. Using the damper, you can stop the movement of air after lighting the stove.

The gate valve is a thin metal plate that is manually adjusted using a special handle. The latter is located outside the chimney pipe so that the user can manually adjust the position of the plate.

Depending on the design and type of damper, it is installed using a special metal frame, or is inserted inside the pipe and fixed with an axial rod.

Important! Do not assume that the valve completely seals the pipe in the “closed” position. According to fire safety requirements, the damper must have a small hole through which weak gas exchange occurs.

The damper in the chimney performs the following functions:

• increases traction force in difficult weather conditions;
• increases the intensity of combustion in the furnace due to increased oxygen flow;
• reduces draft when there is a strong hum in the chimney during strong winds;
• saves fuel by reducing combustion intensity;
• prevents heat loss after the heater has warmed up.

Very important! You can close the chimney with a damper only after the wood has completely burned and the flame has gone out. If you close the damper prematurely, this can lead to a dangerous situation due to the release of large amounts of carbon monoxide into the room. If the damper is closed too late, the efficiency of the furnace will be reduced, because Most of the heat will go out through the chimney.

Purpose and principle of operation

A ventilation damper is a valve capable of completely or partially blocking the movement of air flow in the air duct. The literal translation from German of the word schieber is a valve. The name fully reveals the functional purpose of the device. The device is used in ventilation networks to increase the productivity of their work by regulating the intensity of the passage of air masses. The gate is sometimes called a "throttle valve", but this term does not apply to all devices, but only to those equipped with a rotary locking mechanism.

The principle of operation of the damper exactly repeats the principle of operation of the stove damper used to regulate draft in the chimney pipe. So, when the fuel is ignited, the damper is opened, thereby ensuring powerful movement of air flows from the blower to the pipe. During the active phase of combustion, they close it slightly, preventing instant burning of the fuel, and after the last coals have burned out, the valve is closed almost completely, leaving only a small gap.

Thus, the stove valve plays the role of a draft regulator, allowing you to control the speed and intensity of the passage of air masses through the chimney. The ventilation damper works on the same principle. It either increases or limits the current of air jets. In addition, the damper equalizes the resistance of air flows inside the air duct and regulates their passage from the main part to the branches. Slide dampers can be mounted on air ducts made of any material, including plastic.

Types of gate valves

There are two main types of gate valves - sliding and rotary (throttle). The design features are clear from the name: the first type works due to the perpendicular movement of the metal plate relative to the chimney pipe.

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To increase draft, the damper is moved back and almost completely extends beyond the chimney, and to reduce the flow it is pushed back into the pipe.

Retractable gate

The most popular damper for a retractable type chimney. It compares favorably with other varieties in terms of reliability and ease of use. The retractable gate is a plate with a smooth, even surface, in which there is a special longitudinal hole. It runs along the grooves in the chimney.

This type of valve is installed strictly horizontally. To change the draft force in the chimney, it is enough to move the damper in the desired direction, increasing or, conversely, reducing the cross-section for the pipe.

This option is suitable for steel pipes, but is more suitable for stoves made of brick. Its installation does not require special knowledge or significant effort.

Some models provide a small cut-out area. This ensures the safety of the structure: even if this valve is completely closed, the movement of carbon monoxide in it will continue.

Rotary gate

Another type is a rotary gate. It is a plate made of metal, which is fixed in the central part of the guide by welding.

Dimensions and principle of operation of the rotary gate

Its main portion is located in the inside of the chimney, but the tip should always remain outside. Against the background of rotation of this plate relative to its own axis, the draft in the chimney is regulated.

The disadvantage of this type is the need for fastening by welding. It is this place that is the weak point of the design: the damper will open if the fastening becomes loose.

The rotary gate is characterized by low reliability. But this indicator may vary depending on what it is made from. Most often it is used for installation in steel chimneys. It is also installed in cases where there is not enough space to extend the classic valve.

Cast iron gate

Cast iron dampers have found quite wide application in various types of stoves and fireplaces. The disadvantage of such products is their significant mass. At the same time, cast iron itself has been used for a long time in the production of valves for furnaces. This is explained by its high reliability, durability and strength.

Model range of cast iron gates

Steel type gate

A gate unit made of stainless steel is not the cheapest option. But the design is characterized by high quality and excellent performance characteristics. Its advantages are as follows:

• maintaining furnace efficiency;
• small weight;
• long service life;
• not subject to metal corrosion;
• prevents soot accumulation.

These gates may have different designs depending on the characteristics of the furnace. They are relevant for chimneys made of steel or brick.

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What is a gate valve and its scope of application

A gate valve is a type of shut-off valve in which the gate is a flat plate that moves perpendicularly (in some models at an angle) to the flow of the transported medium.

A gate valve differs from a wedge valve in that its locking plate has a small thickness and, accordingly, a small end surface area when lowered into the seat. In many designs, it is further reduced, giving the shape of a sharpened knife capable of cutting through a medium containing suspended particles. This allows the products to be used to shut off the flow of the working fluid in pipelines transporting liquids with a high content of soft contaminants or small solid fractions.

Gate valves also differ from their wedge counterparts in having a simpler design, shorter overall length and low weight.

Rice. 2 Areas of application for gate valves – bunkers, sluices

Gate valves are used in industrial sectors involved in the production of textiles, liquid and bulk food products, pulp, paper, chemicals, mining, and sewage disposal.

They are used in pipelines transporting commercial oil and petroleum products - gasoline, kerosene, diesel fuel, and are also installed in the supply line for sewage waste or bulk materials.

When mining minerals, they are placed in pipelines that transport slurry - a mixture of water with small solid fractions formed after washing the ore product. The transported aqueous medium may contain particles of coal, cellulose, and ash.

Gate valves are used in gas supply pipelines, air ventilation systems, and chimneys.

Some of their applications do not involve pipelines. For example, gate valves are installed under vertical storage bins, where they control the distribution of filled material. In other areas, special large rectangular gate valves are used as sluice gates (panel gates).

Rice. 3 Main components of knife valves using the example of models PA 510 and PA 520

Related article:

Wedge gate valve - purpose, classification, characteristics, installation . The article describes in detail about wedge valves, where they are used, characteristics and sizes, as well as how to install and operate. It might be interesting to read.

Safety precautions

When talking about gate valves, first of all we should focus on safety precautions. Already from the definition it becomes clear that this device is capable of completely blocking the natural flow of air from the room through the stove and chimney to the street. The oven can be in such a locked state only under one condition - there is nothing in it that is still smoldering even a little, much less burning.

As you know, burning wood in a stove leads to the release of carbon monoxide, which is poisonous to humans. The danger of poisoning with this gas is that a person may simply not feel the harmful effects of the gas until he begins to lose consciousness, and then it may be too late. This danger should not be underestimated: for example, it is known that the famous French writer Emile Zola died in Paris in his bedroom from carbon monoxide.

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An attentive reader may notice that valve manufacturers produce them with special holes that prevent complete blocking of the chimney. However, with regular use over time, soot and resin accumulate on these holes, which gradually reduce their throughput, and then can completely block them. Obviously, the chimney periodically needs to be cleaned and the damper is no exception, but in practice this procedure is carried out much less frequently than required by safety regulations.

Design features of the device

The design of a gate valve or “knife” valve is quite simple. It consists:

• From a body that is a tee with a central extension and hollow branches. Can be equipped with a lid.
• Sedel. These elements perform a guiding function and ensure the tightness of the shutter.
• Locking unit (damper). This element is located perpendicular to the flow of the medium and regulates the throughput of the valve.
• A rod in the upper part of the housing, responsible for moving the damper.
• Control mechanism - screw, lever, drive.
• A stuffing box assembly that ensures the tightness of the rod-housing pair.

Gate valve design advantages and disadvantages:

The main advantage of the fittings is their simplicity of design, low hydraulic resistance and the ability to be used for transporting media with solid inclusions.

Disadvantage: low tightness, high construction height. Such products cannot be used to carry hazardous substances, the leakage of which could be critical.

Differences between retractable and rotary gates

So far we have been talking about the retractable type of damper on a stove chimney, although there is another type - a rotary one. Let's look at how they differ.

The purpose of both types is the same - to partially or completely block the flow of flue/heated gases. The differences relate to the design.

A retractable model is a metal plate that is fixed in a frame and moves along guides in a horizontal position. There are no strict requirements for the dimensions of the device, since they must correspond to the cross-section of the chimney and completely depend on its parameters.

Thus, the valve consists of two main parts:

• frame , which is fixed in the smoke exhaust duct and is motionless;
• plate moving inside the frame.

Typically, both parts are made from the same material to maintain performance when heated or cooled.

A properly designed and installed damper should never completely block a stove chimney. A small gap is necessary for fire safety purposes.

The design of the rotary (throttle) gate does not extend, but rotates along an axis, as the name suggests.

A round or rectangular plate (depending on the cross-section of the chimney) is fixed on a metal rod, the free end of which extends beyond the channel and serves as an adjustment tool.

The simplest model of a rotary gate with a diameter of 120 mm. Manufacturing material – stainless steel. The smoke exhaust channel is closed by turning the handle with a curved end

Gate valves are considered more reliable and wear-resistant devices. The weak point of the rotary devices is the connection between the rod and the plate, which becomes loose over time and renders the valve unusable.

Types and designs

The chimney damper is available in several versions.

Retractable

It is a round or rectangular frame with a plate. The plate extends and retracts, thereby adjusting the cross-section of the chimney.

This option is most often used with brick and ceramic channels. To ensure incomplete sealing and avoid carbon monoxide poisoning, a small hole is made in the plate. The main advantage of this option is ease of installation.

Rotary throttle

A rotary or throttle valve (also known as a hog valve) is a plate made of steel or cast iron that rotates around an axis. The axis is a metal rod welded inside the chimney. Used in steel chimneys.

It is less reliable - over time, the welding fastening of the plate and axle weakens. You should avoid installing a rotary damper in the bathhouse - even when closed, this type of damper partially allows steam to pass through.

In addition, gate valves differ in material (the most common are stainless steel and cast iron) and the method of adjustment.

Differences between retractable and rotary gates

The retractable damper allows you to adjust the working cross-section of the chimney, while the rotary damper only allows you to open or close the pipe. Of course, some tricks are possible - such as securing the hog in an intermediate position in different ways, but the factory equipment does not provide for this. In addition, the rotary gate complicates mechanical cleaning of the pipe.

The hog is often installed in metal chimneys, and the retractable one is installed in brick chimneys.

Which material is stronger

In addition to structural differences, types of gate valves may differ in the material of manufacture. The only possible option is metal, since it is the only one that does not burn or deform at high temperatures, and over time, even in an aggressive environment, does not change its characteristics.

For production, either cast iron or stainless steel is used. It is not possible to build a damper from cast iron yourself, since this requires, at a minimum, a forge. However, you can find both nondescript and beautifully designed cast iron dampers on sale.

Cast iron rotary gate with a comfortable handle. This design is suitable for a brick chimney with a rectangular cross-section, capable of supporting the fairly heavy weight of the device

Steel products look simpler, but their characteristics are similar to their cast iron counterparts. The advantage of steel fixtures is their light weight.

If a cast iron damper for a stove chimney is installed only on a durable, permanent structure, then a steel damper is suitable for any smoke exhaust ducts - brick and steel, rectangular and round, solid and light.

Samples of a galvanized steel damper, chimney cross-sectional diameter – 150 mm. Galvanization, unlike ordinary steel, does not react to moisture (condensation) and does not corrode

When choosing a material, you need to focus on the characteristics of the chimney pipe and the features of the interior.

For a country heating stove, a modest steel valve is sufficient, while for upgrading a Russian stove in a cottage, a custom-made cast iron valve is better suited.

How is the gate constructed?

The design of the device consists of a frame with a moving plate, the displacement of which helps regulate the movement of gases and the intensity of the combustion process. The retractable chimney damper is installed in square, oval and round pipes.

The design of the damper can be of a throttle or rotary type. The guide piece is attached by welding in the center of the plate, its end is brought out beyond the pipe walls. With its help, the thrust is adjusted by turning the plate inside the device. The reliability of this type is lower than the retractable version, because over time the fastening weakens and the plate does not hold in the desired position. The damper type is recommended for a metal chimney.

Selecting a location option

There are three main options for placing the damper in the chimney:

• pipe-to-pipe fastening;
• placement in a fireplace insert;
• installation in a ventilation pipe.

Brick chimney with damper

If you place a gate valve in the outlet pipe or in the furnace firebox, that is, build this element into its design, the damper is placed on a section of pipe as close as possible to the heating boiler. This guarantees ease of control and ease of turning the valve. This is explained by the fact that the handle will not touch either the portal or the cladding area. If it is located according to the “pipe to pipe” option, no additional fastenings are required for connection with other elements of the furnace.

If you place the damper assembly in a pipe intended for ventilation, overheating of the fan motor during its operation is prevented.

Typically, ready-to-install chimneys are offered, which are equipped with everything necessary, including a slide valve. In this case, it is placed in the system in accordance with the manufacturer's instructions. If it is not provided for one reason or another, it is quite possible to manufacture and install this element yourself.

Design

According to design solutions, dampers for air ducts are divided into retractable and rotary. Both round and rectangular gate valves can be of both types. Certain designs are better suited for use in specific systems.

Retractable

The retractable type mechanism is best suited for chimneys that use metal or brick as the starting materials. This type of design allows:

• pass air flows with minimal losses;
• ensure the highest possible level of tightness;
• carry out cleaning and maintenance of the chimney without any difficulties.

Turning

The rotary type valve is not used very often. The mechanism operates due to a rod located in the center. There is no metal sheet attached to it, which rotates around its axis. Due to this, the space is adjusted and covered.

The rotary gate is also called the throttle valve. Its design is quite simple and you can do it yourself without any problems. However, the rotary valve is used quite rarely. This is due to the fact that the moving part of the mechanism has a low level of strength, as a result of which it requires periodic replacement.

Tips for choosing a gate valve

It must be remembered that the correct selection of an element such as a slide damper is reflected in the future not only on the draft indicator, but also on the safety of the heating system, of which the chimney is a part. Installation of the damper is carried out on any model of fireplaces and stoves, except for the most modern ones, which have a deflector.

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The main recommendations for choosing slide valves for smoke exhaust communications are as follows:

• If the heating device operates by processing gas, it is better to purchase a rotary valve model. This is due to the fact that such models exclude the possibility of completely blocking the smoke exhaust channel. Thus, the heating system will be safer. The chimney, which removes combustion products from the gas stove, must be closed by at least 40 percent during operation;
• There are heating systems that operate intermittently (periodic). A closed damper installed in such a heating structure, as a rule, allows steam to pass during supply, and an open damper contributes to the formation of a large amount of soot on the pipe, which is located below the plate;
• It is strictly not recommended to use rotating elements for installation in sauna chimneys.

A rotating device is the most suitable option for a gas-consuming system

Note! The chimney damper is a shaped part of the chimney service, so if you purchase everything necessary for laying a chimney, it will be included with the pipes. Such shutters can be purchased at any specialized store or ordered using an online store on the Internet.

Experts recommend carefully measuring the cross-section of the smoke exhaust duct before purchasing a gate product. Perhaps this is the main thing that needs to be done before purchasing a gate.

Practical recommendations for selection and installation: what to look for

Traditionally, the damper is placed at the outlet of the air duct in front of the fan. If the ventilation network is branched, then it makes sense to install a separate damper for each branch branch. Closing them will increase air resistance and increase the efficiency of ventilation.

To ensure a tight fit of the shut-off valves to the duct air duct, sealing and sealing compounds are applied to the connecting joints: silicone sealant, heat-shrink tape, bitumen-polymer mastic. But when installing gate valves on pipes of ventilation systems, it is impossible to achieve complete tightness of the unit. Since the gate damper, when closed, does not ensure complete tightness of the ventilation system, such models are not used in emergency ventilation systems intended for fire safety. If the part is mounted on duct equipment using a flange element, then it is secured with at least 4 bolts. In a vertical orientation, the bolts are placed on one side. If the damper is installed in a horizontal position, then the bolt heads are on top.

Depending on the operating conditions, products from a certain material are selected. For standard domestic or industrial ventilation, valves made of galvanized steel are suitable. For rooms with high humidity, use a stainless steel option. Stainless steel gates are more expensive, but more durable.

The correct operation of the ventilation system as a whole depends on the correct installation of individual elements. Knowledge of the operating principles and design features of dampers will allow homeowners to select the correct valve and use the capabilities of air ducts more effectively.

Features of installation of gate valves

To install the throttle valve, it is necessary to make markings on the pipe in order to drill holes according to the welded valve structure.

To do this, you need to measure the pipe using a measuring tape and make marks for future holes. After making sure that the marks are symmetrical, use a drill to drill holes for the future rotary handle.

The throttle valve is installed as follows:

1. A steel damper circle with a welded tube is inserted into the chimney pipe.
2. A metal rod is threaded through the drilled holes in the pipe through a small tube, the end of which is secured with a bolt and nut.
3. The end of the rod is bent using pliers for a rotary handle.

Important! It is advisable to install a wooden element at the end of the rod, which will serve not only as decoration, but also as protection from touching hot metal, since the damper will become very hot during operation.

Next, you can install the resulting structure in the chimney pipe. To do this, the first piece of pipe is put on the furnace pipe of the stove heating, onto which a structure with a gate valve is installed on top. The next piece of metal pipe is put on the gate. All connections are treated with liquid silicone sealant.

Installation of a retractable damper in a brick chimney occurs during the masonry process. To do this, after 6-8 rows of bricks, a layer of cement masonry mortar is applied, on which a wire frame is installed with the open side facing the performer. You need to insert a latch into the frame and bring it into the closed state.

The frame is covered with mortar on top and bricks continue to be laid according to the standard pattern.

Attention! The slide damper is allowed to be installed in the first section of the chimney, at a height of up to 1 m above the firebox. This will ensure ease of adjustment of the damper and good aerodynamic properties of the chimney.

Installation features

• When installing the gate at the stage of laying brickwork, the frame is placed at a height of 6-8 rows from the base of the pipe;
• The frame should stand straight, without blocking the outline of the chimney;
• In stainless steel chimneys, the valve is installed using the “pipe-to-pipe” technology. It is necessary to coordinate its dimensions with the diameter of the channel;
• An important nuance - the damper is installed on an uninsulated section of the chimney;
• The height from the firebox to the damper should not exceed 1 m (for metal channels);
• Pipe height from the floor to the valve - 1.8 - maximum 2 m (for brick);
• The damper in the grooves should move freely;

DIY making

The simplicity of the design of the damper plate for the chimney allows you to make it yourself to ensure further regulation of the draft in it.

Option 1. Manufacturing a rotary gate from stainless steel

We offer detailed instructions for manufacturing the damper already with a finished stove heating, when the design is completed, but the damper mechanism was not provided.

To make and install a gate valve with your own hands, you will need the following materials:

• grinder, cutting and grinding abrasive wheel;
• drill;
• tap;
• oil for lubricating the tap when cutting threads;
• hammer;
• vice;
• pliers;
• welding;
• core;
• electrodes for stainless steel;
• compass;
• roulette;
• permanent marker.

The materials you should immediately prepare are:

• stainless steel sheet 1.5 -2 mm thick.
• stainless steel tube with an internal diameter of 6 mm;
• 2 bolts 8mm,
• nail (or metal rod).

When all the tools and materials are prepared, you can begin to carry out the work.

1. Measure the inside diameter of the pipe and mark it on the stainless steel sheet using a compass.

   
   step 1

2. Now, using a grinder, cut out a circle according to the markings made.

   
   Step 2

3. We try on the cut-out damper and, if necessary, modify it with a grinding wheel until it clearly fits into the pipe.

   
   Trying on the damper

4. Take the prepared stainless steel tube and apply it to the finished circle. Use a marker to measure the size of the flap. We make it smaller than the internal diameter by 3 mm on each side.

   
   Step 4

5. We cut the pipe with a grinder and a cutting wheel.
6. We drill an internal hole in the 6.8 mm tube for threading. When drilling, it is necessary to periodically lubricate the inner surface of the tube with machine oil.

   
   Drilling out the tube

7. We cut an 8mm thread on both sides of the tube with a tap, not forgetting to lubricate the tap in the process. To remove the cutting chips, it is necessary to make a half turn back every half turn of the tap along the thread.

   
   Step 5

8. Now you need to make three holes in the damper. Immediately use a marker to make marks.
9. Clamp the tube and the valve in a clamp and weld the tube to the valve through these holes (welded rivets). We start welding from the central hole, then release any one clamp and weld it into the free hole.

   
   Step 6

10. We mark the future holes on the smoker. To ensure that the axis of the holes clearly coincides, wrap the pipe with a tape measure and measure the center horizontally and vertically. Let's drill.

    
    Making the markings

11. We assemble the damper into a tube.

    
    Step 7

12. Making a template for the damper clamp.

    
    Step 8

13. We transfer the markings to the metal sheet. You can use a compass.

    
    Step 9

14. Mark the middle for the fastener holes, cut and drill according to the markings.
15. We weld it to the pipe.

    
    We weld the clamp

Option 2. Manufacturing a horizontal sliding gate from stainless steel

For this option, you need to purchase a ready-made factory stainless steel gate valve. The design represents a frame within which the mechanism moves.

1. Lay out 2 rows of the stove or fireplace according to the ordering pattern used.

   
   horizontal sliding gate

2. On the row where the valve will be installed, we cut grooves in the brick. These are small grooves into which the metal element will fit. It is best to use an angle grinder with a wheel for this work. But if you don’t have such a professional tool, then you can get by with a file.
3. The damper is installed.
4. It is necessary to cut a recess in the side brick for the movement of the damper handle, because it will need to be cleaned of soot during operation.

   
   We block the gate with a row of bricks

5. The next row of bricks is laid and all the resulting gaps are well sealed.

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As you can see, making a gate does not require much time or much experience. At the same time, this is a very important detail that will significantly increase the efficiency of the boiler or fireplace.

Specifications

General technical specifications for gate valves used in main oil pipelines are given in GOST R 55020-2012. Some provisions of this document:

• Nominal diameters (DN). The indicator (sometimes designated as DN) is equal to the cross-section of the internal passage channel, the main standard sizes are: 100 - 150 - 200 - 250 - 300 - 350 - 400 - 500 - 600 - 700 - 800 - 1000 - 1050 - 1200 mm.
• Nominal pressure (PN). Indicates the pressure characteristics of the transported medium at operating temperature parameters, typical range: 16 – 25 – 40 – 63 – 80 – 100 – 125 bar.
• Maximum pressure drops when the damper is opened: 16 – 25 – 30 – 40 – 50 – 63 – 70 – 80 – 100 bar.
• Temperature of the transported medium: - 15 to + 80 °C.
• Tightness: class A without visible leaks.
• Drive: manual with steering wheel, gear, electric.

Rice. 7 Drive types

• Climatic modification: U1 (ambient temperature up to - 40 °C) and HL1 (up to - 60 °C).
• Installation options: underground and above ground.
• Direction of movement of the working fluid: two-way.
• Percentage of suspended matter in the supplied medium: no more than 20%.
• Type of connection to pipes: welded (with welded nozzles or with welded coils), flanged, with mating welded flanges, combined (one nozzle with a flange, the other for welding).
• Body design: cast, cast-welded, cast-stamp-welded, stamp-welded.
• Flange designs: cast, butt welded and flat welded.
• Service life: at least 50 years.
• Designated service life: from 30 years.

Rice. 8 Design and manufacturing materials of a gate valve using the example of Omal brand products of the Pal series (Italy)

• Full and assigned life: 3000 and 1500 cycles, respectively.
• Service life and resource of replacement parts: 15 years and 750 cycles, respectively.

Since gate valves are used not only in pipelines with petroleum products, the above provisions of GOST R 55020-2012 are not mandatory for their manufacturers.

Many companies produce products in a wider range of nominal diameters from 50 to 2000 and even up to 3000 mm.

Also, in comparison with GOST R 55020-2012, the pressure characteristics of manufactured products may differ - for example, any indicator in the range from 1 to 10, 25 or 40 bar, as well as their temperature parameters, drive types (hydraulic and pneumatic drive). Many manufacturers supply products with a wider range of climate options.

Rice. 9 Dimensional and physical parameters of gate valves using the example of products of the PA 570 series

Pipe installation

A gate valve can also be installed on a pipe. To do this, select a section of it where there is no insulation, otherwise it simply jams due to expansion as the element heats up. Experts recommend placing it about 1 meter short of the firebox.

The following procedure is suggested:

1. Fastening the first part to the pipe with coating of the joints with a sealant characterized by heat-resistant properties.
2. Installation of the gate on this segment or on the tee.
3. Placement of the second trim for the pipe, which will connect the structure with the insulated sections of the chimney.

Due to the tight fit of all elements of this design, no additional fastenings are required. The installation technique is suitable for rotary and retractable gates. Sometimes a rotation limiter is additionally provided.

Installing a gate valve on a pipe

How does the installation work?

The rotary damper for the chimney is installed as follows. The height of the product is determined by the craftsman based on the actual structure of the furnace. The minimum height is 0.9-1 meters from the floor, and the maximum is approximately 2 meters. As a rule, installation does not take more time and proceeds in several successive stages:

1. Selecting the installation location and setting marks on the bricks that need to be trimmed.
2. Cutting bricks using a grinder.
3. Fixing the chimney partition with masonry mortar.
4. Brickwork according to a row pattern.

Installing a damper on a chimney

Today, there are two main ways to install a damper on a chimney:

1. Installation in a fireplace insert. This installation option implies the location of the gate product in close proximity to the heating equipment. As a rule, in this case the distance from the damper to the heating apparatus is 1 meter. This arrangement is very convenient for regulating the valve.
2. Connection with other elements of the heating system. In this case, there is no need to use additional locking elements, so this option is quite common. This type of installation can also be called “pipe to pipe”.

Helpful information! In addition, it is worth noting that the gate product can also be installed in the ventilation system. A gate valve for ventilation is necessary to prevent the fan motor from overheating. The fan motor may overheat during shutdown.

The above options for using valves for chimneys and ventilation systems are used everywhere. It is worth noting that today you can find a huge variety of stoves and fireplaces, which differ from each other from a constructive point of view. This variety of heating devices also influenced the range of gate valves. Therefore, the choice of a damper for a chimney depends entirely on the characteristics of the heating device and the chimney design in a particular case.

Gate valve installation

Installation of any type of damper is carried out at the first stages of installing a heating system. Installing the structure on a chimney pipe is not at all difficult. This can be done in three ways:

• Near the fireplace. The device is connected to the chimney pipe at a distance of one meter from the heating devices. This convenient installation of the damper allows you to easily monitor the operation of the gate.
• "Pipe to pipe." This method involves attaching a slide damper to a chimney pipe without the use of additional clamps. The valve is held securely due to its tight connection to the chimney pipe.
• In the ventilation duct. This installation option is mainly used to cool the fan motor.

When constructing stoves and fireplaces, the damper is most often installed using the first method. Gate valves are used for both round and square chimney pipes. Products with a rotating plate are most often installed in chimneys with a cross-section in the form of a circle.

Installing a damper in a brick oven

The gate valve is quite often used for brick kilns. It is installed during the construction of the chimney. Place the valve on the first meter of the pipe. This arrangement of the gate makes it easy to adjust the draft. To install such a gate you need:

• two rows of chimney bricks are laid;
• in the second row an opening of the required size is cut;
• a damper is installed;
• in any brick of the same row a recess is made for a rotary handle;

Next, the next rows are laid

In this case, you should pay attention to the tightness of the fit to the place where the gate is installed. All cracks should be sealed with mortar.

When using such a damper, all safety precautions must be taken into account.
During operation of the furnace, under no circumstances should the gate valve be closed. This action will lead to carbon monoxide entering the room. Some models have a special fixing element that prevents the pipe opening from being completely closed. Date: September 25, 2021

Advantages and disadvantages

Like any engineering solution, a gate has a number of advantages and disadvantages.

Pros:

• Possibility of traction control;
• Fuel economy;
• Dampers help retain heat.

Minuses:

• The devices make it difficult to clean chimneys;
• If installed incorrectly, the gate may jam and negatively affect the movement of gases;
• To make the correct adjustment, you must have some knowledge in the field of smoke exhaust systems.

Visual demonstration of the efficiency of a gate valve (video)

Closed gate:

Open gate:

In most cases, the gate is made of stainless steel with a thickness of no more than 1 mm. This part can withstand temperatures up to 9000C, is resistant to corrosion and has a low coefficient of thermal expansion.

In order to ensure maximum ease of operation of the chimney and good soot removal, the surface of the damper must be polished.

The joints are joined using the rolling method.

A standard damper covers up to 85% of the chimney, which is the optimal indicator for the effective removal of combustion products.

The design of a gate valve and materials for its manufacture

The main components of a typical gate valve are:

Frame. It consists of a main part and a cover (in many designs it has a stand with a yoke assembly), connected to each other with bolts. The main materials for the manufacture of body parts are carbon steel grade WCB (analogues of cast steel 20L, 25L, 30L), stainless steel (for example 20Х13, CF8, CF8M, AISI 304, AISI 310, AISI 316), gray (SCh20, SCh25) and high-strength nodular cast iron (ductile iron) grades GG-40 or GG-25.

Exclusive case materials include aluminum, bronze and AISI 904L uranium.

Typically, valve bodies are coated with a blue epoxy or powder-epoxy compound approximately 250 microns thick.

Shiber. Most often, the gate plate is made of corrosion-resistant metal alloys, which are AISI 304, AISI 310 or AISI 316 stainless steel.

Spindle. The element is responsible for moving the bolt plate, usually made of stainless steel (20X13).

Rice. 4 Materials for the manufacture of seals in SMO brand products and their varieties

Seat seals. Main materials of seat seals in gate valves:

EPDM - ethylene-propylene-diene elastomer (EPDM) is used as a sealant when transporting media with an operating temperature of + 90 °C and a maximum temperature of no more than + 125 °C.

NBR is acrylic-nitrile-butadiene rubber, it has a relatively low heat resistance with a maximum threshold of no more than + 90 ° C; when using it, the temperature of the working environment should not be higher than + 80 ° C.

Viton (FKM, FPM) is a class of synthetic fluorinated rubbers (SFK), which have a maximum temperature threshold of + 200 °C, and can be operated for a long time at a temperature of + 180 °C.

PTFE is a well-known white fluoroplastic with a soapy surface to the touch. The material has a very low coefficient of friction and the highest heat resistance among all seals at + 270 ° C. It is mainly used as an oil seal; when used in seats, fluoroplastic does not provide 100% sealing.

Nitrile (Nitril) is a synthetic butadiene-nitrile rubber (rubber), resistant to petroleum products, oils, acids and low concentration alkalis. Withstands operating temperatures up to + 90 °C.

Hypalon (CSM) is a product from DuPont that is a chlorosulfonated polyethylene elastomer (CSPE). Hypalon is a general purpose rubber with good mechanical properties and high resistance to abrasion, wear and aggressive chemicals. The maximum temperature threshold for CSPE-based rubber reaches + 120 °C.

Silicone - organosilicon silicone rubber is an elastic material that can function in the temperature range from - 60 to + 300 ° C (withstands 500 hours). The maximum operating temperature of silicone rubber with a service life of 20 years is + 120 °C. Silicone is resistant to oxidizing agents, oils and organic solvents, has a low coefficient of residual deformation, that is, it easily restores its shape. The disadvantages of organosilicon silicone rubber include its insufficiently high tensile strength compared to other elastomers.

Rice. 5 Design of gate valves according to GOST R 55020-2012

Oil seal packing. In gate valves, the gland provides a seal in the body of a moving flat plate and has an internal surface shape corresponding to an elongated rectangular gate. The following materials are used as its packing and ring gaskets:

• Dry cotton fiber, used in general purpose installations working with solid bulk materials.
• Oiled cotton fiber. It consists of woven threads impregnated with grease. Is a packing for standard shut-off valves operating under pressure.
• Cotton Fiber with PTFE is a general purpose padding made from woven Teflon-impregnated cotton fibers.
• Teflon acrylic fiber. It is a synthetic acrylic thread impregnated with Teflon using vacuum dispersion technology. It is a typical packing for valves operated under pressure in aggressive liquids (oils, oxidizers, alkalis and acids) or with suspended particles.
• Fibrous (lubricated) PTFE. Fluoroplastic fibers with a diagonal weave system can function at high speeds of gate movement in almost any aggressive environment, including those containing solid fractions.
• Heat-resistant graphite fiber is a diagonally woven thread impregnated with a lubricant made from a similar material. The packing is universal, as it can withstand not only high temperatures of vapors, gases and liquids, but also their aggressive chemical composition. Graphite is not afraid of oils, solvents, the vast majority of alkalis and acids.
• Ceramic fiber is used in gate valves that handle high temperature air or gases at low pressures.
• PTFE, nitrile and EPDM are used as rectangular gaskets.

Frequent errors and problems during installation

• Installation of a valve in an insulated area. Under the influence of thermal expansion, the damper may jam;
• Installation of a cast iron part in a metal chimney (cast iron weighs a lot);
• Using too thin steel or stainless steel with a low nickel content for the manufacture of valves. Such a product quickly deforms under the influence of hot gases and can burn out;
• Installation of a gate with a non-smooth surface;
• Installation of a valve without a hole for carbon monoxide release;
• Installation of handles that do not allow monitoring the position of the valve (applies to rotary elements).

Features of gate maintenance

The gate, made of stainless steel, is usually polished to perfect smoothness. Soot settles on it poorly, but still settles. Therefore, it must be cleaned periodically.

The horizontal valve can be cleaned simply by pulling it out to the maximum and applying a special solution. Rotary - cleaned through the chimney with a special plastic brush. You should also ensure that the damper moves freely along the guides. It is allowed to periodically lubricate them with an anti-corrosion compound.

Types of ventilation dampers

Modern production offers the most diverse range of valves designed for use in ventilation systems. However, the entire existing set of gate types can be grouped into several categories:

The shape of the dampers is determined by the shape of the ventilation shaft - most often round valves are used, but in some cases rectangular valves are needed:

• There is a need to hide the gate while ensuring the minimum possible use of space.
• When installing ventilation systems that use electric heaters, since they themselves are predominantly rectangular.