How to install a check valve for ventilation. Correct installation of a check valve for ventilation

Often the ventilation system does not work efficiently and part of the air penetrates from the ventilation duct back into the apartment. The effect of reverse draft ventilation is especially noticeable in the kitchens or in the bathrooms of apartments. Check valves will help fight unpleasant odors.

The principle of operation of the check valve ventilation

Check valves in ventilation are called a group of protective devices to prevent the rotation of the air flow in exhaust ventilation systems or simply reverse draft ventilation in apartments. The valve passes air in the right direction, inhibiting the reverse movement. Check valves for exhaust ventilation work automatically and this is the main plus of their use. In ventilation systems of residential and public buildings, check valves are used to prevent air from entering a common ventilation duct into individual rooms.

Check valves for exhaust ventilation work in systems with natural and mechanical draft. The valve protects against the penetration of insects, dust into domestic ventilation.

If the system is not equipped with a check valve, drafts may occur.

Types of ventilation check valves

The main structural part of any non-return valve for natural ventilation is the shutter. It is he who does not allow air to pass in an undesirable direction.

There are two types of round and rectangular check valves for ventilation:

• with a gate in the form of a spool;
• with a shutter in the form of a disk or flap.

The former are used to work with liquid media. The second ones are designed specifically for ventilation. They are available with a horizontal axis of rotation or vertical, as well as single-leaf and double-leaf.

Check valves for ventilation are produced in rectangular and round, with different cross-sectional diameters.

The main parameter when choosing a check valve is its capacity.

Non-return valves for natural ventilation are easy to manufacture and very reliable.

They are made of plastic or metal, the material is selected depending on the characteristics of the system. In vertical pipelines, the air flow moves vertically, so the valve is mounted horizontally, which ensures the correct operation of the valve.

The most commonly used are round and rectangular check valves with a capacity of 4 to 6 m/s. They work silently and efficiently. They are installed both independently and complete with an exhaust device.

All check valves for rectangular or round ventilation are also divided into:

• Heated. Such check valves for ventilation with an electric drive have the advantage: no condensate is collected in the system, and the structure will not be covered with frost in severe frosts;
• Without heating. Good for indoor use only.

The presence of an electric drive at the check valve for ventilation requires the participation of an electrician in its connection.

Although the device is cheap, the check valve for ventilation can be assembled with your own hands, but more on that later.

Check valve design for ventilation

The device of the check valve is very simple: the flap disc is attached to the axis, allowing it to swing freely. To cover the valve when the fan stops, a plumb line is attached. Vent valves can be rectangular, round or square.

Industrial models differ from non-return valves for domestic ventilation in diameter and material, they belong to the explosion-proof category, although the device is the same.

The diameter of a round or rectangular check valve for industrial ventilation can be from 125 to 1000 mm, they are installed in explosive industries.

The butterfly valve model with two blades is widely used.

Butterfly devices are often made of metal, the axis for attaching the blades is installed in the middle of the section. As soon as the fan stops, the blades cover the section and the reverse draft of the ventilation in the apartment stops. The diameters of the bicuspid valves vary from 100 - 315 mm.

An improved modification of the "butterfly" is equipped with seals that reduce noise during operation of the blades.

Very often used for ventilation in the kitchen check valve in the form of blinds or petals (inertial grille). There are several blades in the design, they are located on horizontal axes.

How to choose a check valve

When purchasing a check valve for kitchen ventilation or in a bathroom, you need to take into account the speed of air movement, because the shutter must respond to even the slightest flow. Poor draft in the system is the main problem when organizing a natural ventilation system. Therefore, most owners combine the valve with an exhaust fan. To cover the structure from the side of the room, a beautiful ventilation grill is installed.

But in order for the natural ventilation system to work flawlessly, it is important to choose the right check valve. Otherwise, back draft in the ventilation of an apartment building will continue to poison the existence of residents.

You should pay attention to:

• section shape;
• section diameter;
• valve material;
• valve device;
• valve purpose;
• manufacturer (affects more on the price than on the quality of the simplest mechanism).

You can purchase a ready-made kit of a fan and a check valve. Here it is necessary to pay attention to the power of the fan. For the kitchen, it is suitable with a factor of 10, and for the bathroom and toilet, 7 will be enough.

When purchasing a non-return valve for domestic ventilation of a private house, it is important to take into account climatic conditions. For example, a "butterfly" will be covered with ice faster than a single-axle structure. In private houses, in contrast to apartment buildings, residents are not annoyed by reverse draft in the apartment, but by wind blowing into the ventilation and penetration of rodents into it.

Do-it-yourself check valve for ventilation

The installation of a do-it-yourself ventilation check valve is especially relevant for residents of the last floors of houses, where the problem of dragging "foreign" odors through the air ducts of the general exchange system is common.

We offer an improved model of the ventilation check valve with an electric drive and a fan.

Thick plastic or textolite is suitable for the base of the kitchen ventilation check valve. You need a plate with a size that covers the outlet of the exhaust duct and a thickness of not more than 4 mm. Markings are made on the plate: a grid the size of a fan hole, as well as holes for mounting to the wall (at the corners) and for mounting the fan.

The larger the grid cells, the denser the leaf material must be!

To prevent air from “walking” between the base and the fan, a rubber gasket is used.

To prevent not only reverse draft in the ventilation of an apartment building, but also the penetration of insects, a small plastic mesh or even a nylon from tights is attached to the base grate. The latter is easily replaced. And so that the residents are not disturbed by the vibration from the fan motor, rubber shock absorbers are used during installation.

Shutters are used from thick polyethylene (not less than 0.1 mm). The film should be perfectly smooth, the smallest waviness will break the tightness of the ventilation, and the reverse draft in the apartment building will resume. You can mount the sashes on adhesive tape with a fabric base. Detailed instructions for making flaps for a plastic ventilation check valve in the video:

We recommend cutting the sashes in place, from an already glued piece of film. Moreover, if it is slightly wrinkled during operation, it must be changed. Two sashes are cut between themselves only at the very end of the process. You need to cut with a sharp construction blade.

Use self-adhesive foam tape to ensure there is no gap between the homemade plastic check valve for ventilation and the wall.

During operation, it is necessary to periodically clean or change the plastic mesh, which is clogged with dust.

With proper manufacture, such a home-made plastic check valve for ventilation will last for more than one year. And the residents of the apartment will permanently get rid of the reverse draft, which is typical for the ventilation of apartment buildings.

Installing a check valve for ventilation solves the problem of odors from the street entering the room. In private households, very often a situation may arise when the installed ventilation system does not fully fulfill its functional significance. In other words, odor-saturated air is partially removed from the room, and a situation may also arise when extraneous street odors enter the home through ventilation channels.

In this article, we will reveal in detail the question of what a non-return valve is, what varieties of it exist, and also how to install this device with your own hands.

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Purpose

This type of mechanism is designed to control the increase or decrease in air flow in the ventilation system. The main task of the valve is the removal of clogged air, as well as an obstacle to the entry of various kinds of odors into the room.

The design of this mechanism is quite simple, and includes the following elements:

• frame;
• the main axis on which the damper is attached;
• a counterweight that automatically closes the shutters when the fan stops.

It's important to know: the non-return valve in no way enhances the operation of the ventilation system. It just controls the air flow.

The modern market of ventilation equipment today has a very wide range of check valves of various modifications.

Varieties

To choose this device correctly, you need to know how and where the mechanism will be used.

Depending on what material the structure is made of, check valves are divided into two types:

• galvanized (this type resists corrosion well, but condensate accumulates on the walls);
• plastic (quite practical and easy to install).

Depending on the form, there are:

• rectangular;
• round.

It is worth noting: the choice of a check valve in shape largely depends on the cross section of the ventilation ducts of the system.

Depending on the location of the dampers, these valves are divided into the following types:

• horizontal;
• vertical.

The choice in this case depends on the direction of air flow in the ventilation system.

Depending on the functional purpose, check valves are divided into the following types:

• Butterfly mechanism.

The damper of this type of valve consists of two plates, which are mutually spring-loaded.

The principle of operation is that the plates open with a forced air flow, and close under the influence of a spring element. The most common application of this mechanism is in combination with a sufficiently powerful fan.

• Membrane household type.

A design feature is a flexible plastic shutter, which opens under the influence of air pressure, and when it disappears, it is hermetically pressed against the body.

This type of mechanism can only be used with low-power domestic exhaust fans.

• Petal type. The principle of operation is absolutely similar to the previous case, however, with the difference that the damper is rigid and is fixed on the axis.
• gravity type. A feature of the check valve of this model is that the plates are opened by air flow, and closed by their own weight.

Selection criteria and installation

In order to choose the right check valve, you should adhere to the following recommendations:

1. 1. 1. 1. 1. 1. • the price must correspond to the quality (the size of the mechanism can also affect the cost);
                  • it is necessary to take into account the natural factors of the region, as they can significantly affect the operation of the valve;
                  • pay attention to the appearance of the mechanism grille - it should be decorative;
                  • complete with the device, it is desirable to choose a fan, without which the check valve can turn into a conventional valve.

When installing a non-return valve with your own hands, you should adhere to the main rule, which is as follows: for the successful installation of the mechanism, you must clearly know the direction of movement of the air pressure, and directly install the valve itself according to the attached diagram. If the streams are mixed up, then there is no need to talk about the proper functioning of the device. Leave a message and your contacts in the comments - we will contact you and together we will make the publication better!

The check valve for ventilation is necessary for the effective operation of the ventilation system. It eliminates the possibility of turning the air flow in the hood, thus ensuring the flow of exceptionally fresh air into the home.

Quite often, the apartment begins to function inefficiently. It is easy to notice this by the appearance of unpleasant odors in the home. Such situations arise due to the fact that reverse draft is formed in the ventilation system. This is understood as the phenomenon of the return of part of the air from the ventilation duct to the living quarters.

Backlash can occur for the following reasons:

1. Incorrect installation on the roof of the exhaust pipe.
2. A small amount of supply air entering the natural ventilation system.
3. In one of the apartments in the high-rise building, a powerful forced exhaust hood was installed, which led to violations in the operation of the general house ventilation system.

Powerful forced draft

Most often, problems with natural ventilation occur when the check valve fails. This device is set up very simply. Its main structural element is the shutter. It can only open with airflow in one direction. And when the air movement changes its direction, the shutter slams. Due to this, the reverse thrust stops. The shutter for devices operating in natural ventilation systems is made in the form of a flap or a disk. Such devices can have a different size and configuration (rectangular, round) section.

The non-return valve, in addition, can be heated and operate without heating. The first type of devices is installed on ventilation systems equipped with an electric drive. Heated valves eliminate the risk of condensation in the ventilation and the formation of frost on its internal parts during extreme cold. The key parameter of the described devices is their throughput potential. To ensure effective ventilation of a standard-sized dwelling, the value of the latter should be at the level of 4-6 m / s.

Devices for preventing the formation of reverse thrust are made of plastic and metal. Metal devices are considered more durable. But during operation, they make quite loud sounds (claps), condensate often settles on such valves. Among other things, they are prone to rust. For these reasons, many now decide to purchase a plastic check valve. It functions almost silently and is inexpensive. True, its service life is much lower compared to metal products. We add that the devices of interest to us not only prevent back draft, but also prevent dust and small insects from entering the ventilation.

According to their structure, the devices described in the article are of four varieties - membrane, single-leaf, such as blinds and a butterfly. Diaphragm type valves are supplied with a flexible damper. It reacts to the smallest air movements, so such devices are considered the most sensitive. The single-leaf check valve is made in the form of a damper. It is fixed on the horizontal axis. The air flow rotates the damper, due to which the natural ventilation passage is closed and opened.

Mechanisms such as blinds have 2-4 horizontal axes, on which a number of blades are installed. Such devices are often referred to as gravity and reed valves. Butterfly-type mechanisms are also quite widespread. Usually they are made of metal and installed on ventilation systems equipped with an electric fan. Butterflies have two flaps located on both sides of the same axis. The disadvantage of such valves is high noise during operation. It can be reduced by mounting sealing elements on the butterfly blades.

Butterfly type check valve

When choosing a check valve for ventilation, it is necessary to pay attention to the material from which it is made, its structure, shape and cross-sectional diameter. It is important to remember that in a residential area such a mechanism must respond to air flows that are insignificant in intensity. In this regard, experts advise, when arranging natural ventilation, to supplement the valve with an exhaust hood (that is, a special fan). On the wall, such designs do not look very nice. But that's not a problem. You can always cover the installation site of the hood and damper with an elegant ventilation grille.

Note! Butterfly mechanisms in temperate latitudes are covered with frost much more often and faster than ordinary single-leaf products.

One more nuance. If you purchase ready-made kits for natural ventilation of your home (valve plus fan), you should pay special attention to the amount of exhaust power. Everything is simple here. For bathrooms, you should buy kits with a power factor of 7, and for kitchens - with a factor of 10.

Prudent owners can save the family budget. If there is a desire, it is quite possible to make a valve for ventilation on your own. True, the exhaust fan still have to buy. However, the costs will still be lower.

With your own hands, the described valve is done like this:

1. Take a 3–5 mm thick piece of textolite or durable plastic. Saw a plate out of it. It must have geometric dimensions corresponding to the parameters of the ventilation hole. The plate will serve as the basis of a homemade device.
2. Drill several holes in the finished product (along the edges). Some of them are needed for attaching the base to the wall surface, some for fixing the fan. Also, holes must be made in the center of the plate. Through them, air will enter the room. The size of the holes and their total number is selected at your discretion. The main thing to remember is that the throughput potential of ventilation will be the higher, the more "holes" you drill in the plate.
3. Attach a hood to a plastic or textolite base made by yourself. It is advisable to put a rubber gasket at the site of its junction with the plate. Then the tightness of the structure will increase significantly. You can also place rubber pieces under the fasteners to reduce the amount of vibration and noise the fan makes during operation.
4. Take a sheet of thin plastic or a dense (thickness above 0.1 mm) polyethylene film. They are needed to create sashes. Glue the film (plastic) to the plate. Important! Homemade sashes are required to close the ventilation holes completely. Initially, glue the plastic or polyethylene whole. And then divide them into two parts (they should be the same in size).

Making a non-return valve with your own hands

Now you need to put the do-it-yourself valve in the ventilation duct and securely attach it with dowel-nails or to the wall. The gaps formed between the wall surface and the installed mechanism must be sealed with a good sealant. The next step is cutting the sashes in half. How to do it right, we said above. We only add that the cut should be perfectly even. This is easy to achieve if you use a sharp mounting knife to separate.

That's all. You have made an excellent diaphragm valve for natural ventilation, which is in no way inferior to factory devices in terms of its efficiency. It is guaranteed to last you 2-3 years. The principle of operation of a homemade device is simple. The shutters open under the influence of the flow, passing air from the living room into the ventilation duct. If there is a reverse thrust, the film slams shut (and absolutely hermetically). This means that air does not get into your home from the common house ventilation system. If you need forced ventilation of the room, you just need to turn on the exhaust fan.

Supply and exhaust ventilation must perform its functions in any period of the year and in any weather, that is, to ensure sufficient supply of clean air and removal of exhaust air. A non-return valve for ventilation plays an important role in effective air exchange. Such a device is often used in a natural and forced ventilation system.

Causes of reverse thrust

Sometimes it is impossible to ventilate the room due to the return of air from the ventilation duct with an admixture of all kinds of odors. This happens when the balance of the volume of incoming and outgoing air is disturbed due to clogging or narrowing of the common ventilation duct. And also due to the installation of high-power fans in other apartments, the exhaust air does not have time to be removed outside and returns from other rooms. This is more common on the upper floors. Since the channels of the kitchen and the bathroom are connected, the fan installed in your own apartment in the bathroom will provoke a reverse draft towards the kitchen.

Backdraft problem

In the houses of old buildings, mines were designed for a lower air flow capacity and cannot cope with large volumes from modern powerful hoods. A non-return valve for ventilation helps to organize an air exchange acceptable for the room. It helps to change the amount of exhaust air and let it pass only in one direction, blocking the movement back. Thanks to him, all kinds of smells from adjacent apartments do not enter the housing, and dust, fluff and insects do not fly from the street.

Principle of operation and internal structure

The purpose of the non-return valve is to regulate and act as a damper against reverse air flow. The principle of operation of the check valve is as follows: flaps hanging on a central or several parallel axes rise under the pressure of the air flow in only one direction, and when calm, the petals (lamellas) fall under their own weight or with the help of springs, preventing reverse movement.

In addition to stopping the reverse flow, the valve also has the function of regulating the volume of conducted air, when the cross-section of the duct changes by turning the damper by a certain angle. Devices are two-position, where only two positions are “open” - “closed” and multi-position, when they can be adjusted to change the throughput.

Varieties and types

Consider the technical characteristics and types of check valves in several categories:

• Based on the shape, three types can be distinguished: round; rectangular or square.
  Apply such dimensions that fit a particular duct. In everyday life, for a house, apartment, bathroom, bathroom, round valves with a diameter of 100-125 mm are used; for ventilation in factories, they are suitable with a diameter of 125 mm to 1000 mm. The length of rectangular valves ranges from 7mm to 72mm, and the width (height) ranges from 100mm to 1000mm.
• The material of manufacture can be metal (galvanized steel, aluminum alloy) or plastic. Plastic products are more common, as they make less noise when opening and closing the blades. Due to their lightness, they are more used in everyday life, where the air pressure is not very large. Metal structures are characteristic of industrial models. They are heavier than plastic and close under their own weight. They are more reliable and resistant to aggressive environments, they belong to the explosion-proof category. But there are also disadvantages: metal ones corrode, and condensate collects on galvanized dampers.
• Mounting method is horizontal and vertical. It is installed in one way or another based on the technical data of the valve and the corresponding design of the supply or exhaust ventilation duct.
• The control can be manual or electric. A manually operated valve is manually adjusted with a lever or a gate valve, and for round ones with a valve. Such devices are used in natural supply or exhaust ventilation. The electric valve is involved in the circuit with mechanical devices (fans, hoods) and controls the volume of the passing air flow automatically (damper position sensors).
• All types of valves can be divided into two groups: heated (with electric drive) and without heating. The advantage of a heated valve is that it does not freeze in the cold and does not accumulate condensate. Without heating, it is only suitable for use inside the house of the air duct.
• By type of construction, there are such varieties: membrane; petal; butterfly; lattice.
  

check valve application

Natural ventilation

Suitable for both supply and exhaust ventilation. In the outer wall of the houses, a supply ventilation valve is installed, equipped with a check valve or damper. It can be equipped with an air filter. The use of a supply valve in natural ventilation ensures good access of clean air to the dwelling with protection against back draft and heat preservation. A valve or damper allows you to adjust the intensity of the air flow.

It also makes sense to install a grill with movable shutters on the supply air ducts. They direct the air flow only inside the room.

The use of a flexible membrane in the ventilation grille in the kitchen is simply necessary, where a powerful flow from the hood and other rooms is discharged into one shaft to prevent its return. The membrane structure simply must be very sensitive to the slightest air movements, since there is no high pressure during natural air exchange.

In natural ventilation, a double-leaf valve with springs, which requires a lot of pressure to open, cannot be used. In this system, a device with a single petal works more efficiently.

Application in case of forced system

Such a device is well combined with mechanical devices for extracting, for example, a kitchen hood. It is installed together with the hood.

In models where the hood with a check valve is included, it acts as a damper. When the hood is turned off, the damper closes the channel, preventing odors from the common channel from entering the kitchen. The air duct from the hood should not close the exit opening to the common ventilation shaft, leaving it for natural ventilation. In addition to the grating, you can install a single-leaf damper or a fan with a damper.

In more powerful hoods, a butterfly valve is used. Such designs entail additional costs. The channel from the hood is led directly to the street through an external wall, leading directly to the exhaust air. To prevent cold air from entering the house, an inertial grate is installed on the wall outside.

Inside the house or apartment, in order to organize proper air circulation in all rooms, inertial grilles are installed in the interior walls, and more often in the door. Such inertial grilles contribute to air movement in the direction from the rooms towards the kitchen, to the common ventilation duct, and not vice versa.

Check valve tee and its application

For high-quality air exchange, when installing air ducts, special tees are used, which allow you to correctly combine natural and forced ventilation.

Due to inefficient ventilation in the bathroom and the bathroom, stagnation of dampness and mold formation are often observed. To prevent the entry of foreign odors, as well as to quickly remove moisture, an exhaust hood combined with a check valve is used. But the fan power should not be large so that the central ventilation duct can cope with the air flow.

It should be remembered that it is necessary to regularly clean all shut-off and control devices to maintain their performance.

How to choose a finished product

In the functioning of ventilation, the main problem is poor draft. It is enhanced by combining all types of ventilation with the use of a check valve.

When choosing a check valve, it is necessary to take into account the compatibility of all devices and mechanisms for the following factors:

• The shape and diameter of the cross section of the channels. Select the valve and fan according to the size of your duct, so that there are no problems during installation. Many models of valves have been developed with various round and square shapes and sizes. Usually in everyday life air ducts and check valves with a size of 100 mm are used. The square valves have proved to be reliable and can be easily fixed in square shafts.
• The material from which the product is made must be suitable for the type of system so as not to impair its functioning. Indeed, in natural ventilation, the shutters must respond to the slightest fluctuation of air, which means they must consist of the finest material. And in industrial hoods, devices must be resistant to aggressive environments and temperatures, so galvanized steel or aluminum is used here.
• Purpose and device. Consider the room for which the valve is selected. It must match the power of the fan used so that it is enough to open the petals. For example, if for a bathroom it is enough with a coefficient of 7, then for a kitchen - 10. There are ready-made models in the complete set of a fan with a valve.
• It is important to consider the capacity of the check valve. In everyday life, products with a throughput of 4-6 m / s are used. The volume of air removed from the apartment should not exceed the patency of the common ventilation shaft, otherwise it will be distributed to other apartments. Otherwise, it is necessary to install a separate air duct with an outlet to the street.
• Due to climatic conditions, some devices are mounted only indoors, as they cannot stand low temperatures. For example, a butterfly from frost will quickly become covered with frost. For a private house, it is necessary to take care of the characteristic wind blowing and the penetration of rodents.
  A properly selected valve guarantees the quality of your ventilation and comfortable living conditions.

Do-it-yourself placement and installation rules

Initially, we determine the installation locations of check valves in the ventilation scheme. Consider an example of installation in a ventilation shaft behind a fan.

1. Disconnect the hood from the power supply and dismantle.
2. We insert the valve into the opening of the duct and mark the attachment points on it. We take it out and drill it along the marked holes.
3. Again we insert the device into the channel and similarly make markings on the wall, then, having removed the valve, we drill holes in the concrete opening using a jumper.
4. We hammer dowels into concrete and fasten the device.
5. We carefully cover the gaps along the edges with silicone sealant to prevent air leakage and weakening of the flow power.
6. Finally, install the hood in place.

Recently, non-return valves have appeared in the assortment, which can be installed in front of the fan - overhead. Their fastening is not so troublesome - it does not require dismantling the fan. A grille with a non-return valve is installed before the entrance to the ventilation duct or at the exit from it. It can be easily installed with your own hands by attaching it to the ventilation opening using self-tapping screws or “liquid” nails.

At the exit of the ventilation shaft, a single-leaf gravitational action valve and a double-leaf damper using springs together with a powerful fan are applicable.

DIY creation

For natural ventilation, it is not difficult to make a valve yourself.
Work progress:

Output

All sorts of odors will not penetrate into the home if a check valve is installed on the ventilation. The simplest device allows you to organize high-quality and efficient ventilation of the premises, maintaining a favorable microclimate in them.

Are you satisfied with the ventilation in your apartment? If you answered the question in the affirmative, then everything in your house was done by real experts, without flaws. But this is not always the case: very often ventilation shafts have irregularities on the inner surface or narrowing of the cross section. All this as a whole leads to the fact that the air flow can enter the apartment when the fan is off.

This phenomenon very often also occurs due to clogging of ventilation. The flow of air entering the general ventilation from the lower floors easily fills the apartments of the residents of the upper floors. This happens only when the fan in your apartment is turned off. So what happens? Keep the fan on all the time?

In this case, the energy consumption is too high, and the device will fail prematurely. The installation of a check valve will save the situation. Such a simple device will not increase the ventilation in the apartment, but it will provide a barrier to the air flow into your apartment.

Check valve types

There are two types of check valves: with vertical and horizontal dampers. The choice of a certain option should be made depending on the direction of movement of the main air flow in the ventilation shaft. The next important point is the material from which the dampers (curtains) of the check valve are made. Metal structures seem to be more reliable.

They are more durable, self-closing under the influence of their own gravity. The disadvantages include only the reaction of the metal to the impact of an aggressive environment. Galvanized (or otherwise treated) dampers will not corrode, but condensation will certainly collect on them.

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check valve design

The design of the check valve can be any. Ventilation options with butterfly curtains are the most popular among consumers. Such a unit works very simply: inside the valve body there is a vertical axis on which two curtains are located. When overpressure is created from the forced ventilation side, the shutters fold in and open access to the ventilation well.

When the fan is turned off, the curtains return to their original position due to the spring or counterweight. Such a valve for ventilation requires careful adjustment, since it can only block the air flow with a rather impressive effort from natural ventilation. As a rule, the non-return valve is not adjustable, so when choosing a product, you must immediately pay attention to its sensitivity.

Interesting is the design of the valve with a horizontal arrangement of shutters. In the normal position, all curtains are vertical. Loops are located at the top of each curtain. Curtains under the influence of their own weight tend to the ground and block the air flow. When the fan for forced ventilation is turned on, the curtains under the influence of pressure take a horizontal position and open the air flow.

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How to make a valve with your own hands?

Is it necessary to buy a ready-made check valve? You will have to solve this issue yourself. As you may have guessed, almost any man can make such a check valve. It makes no sense to make more complex designs on your own, for the reason that it will take a lot of time and the costs will be disproportionately higher than when buying a finished product. The price difference for valves is quite noticeable. The simplest designs are ten times cheaper than more complex counterparts.

By the way, expensive non-return valves are not available in retail trade, as they are sold complete with fans.

This makes a lot of sense: the design of the damper is calculated for a specific fan model, so it will work perfectly in tandem with this fan. In another set, a mismatch can greatly affect the operation of one of the devices.

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Tools and materials for installation

The check valve for ventilation is easy to install. You only need to have:

• check valve;
• assembly instructions;
• screwdriver (you can limit yourself to ordinary screwdrivers);
• self-tapping screws;
• sealant (or silicone).

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Phased work

First you have to dismantle the fan that you have successfully used. We install the non-return valve body in the ventilation hole and make marks on the places of the intended fasteners. The case is to be removed, and on the resulting marks you need to drill holes.

We return the case to its original place and through the holes we make marks on the walls of the well for ventilation. We remove the valve again, and holes will have to be made on the marks obtained. You definitely won’t be able to use a puncher, so you have to use a jumper (a device for making holes in concrete bases mechanically).

We hammer dowels of the appropriate size into the holes. It remains only to return the check valve to its place and wrap all the fasteners until they stop. Pay attention to the resulting holes or gaps between the check valve body and the ventilation well. If their size is visible to the naked eye, then the installation of the check valve will have to be supplemented with sealing. The simplest thing is to silicone all the gaps.

This moment cannot be ignored, since the air draft will not be sufficient to close the valve shutters. This will not harm ventilation, but the valve will either not perform its main function, or will not be fully. After completing all the described work, it is necessary to install the fan in its original place. On this, we can consider the mission accomplished: the ventilation will work reliably, the check valve will not let foreign odors into your house.

Currently, non-return valves have begun to appear on sale, which do not imply such drastic changes. Such devices are not mounted behind the fan, but directly in front of it. Such peculiar valves are overhead. They work no worse than previously described. The only peculiarity is that the valve will protrude somewhat above the plane of the wall. With a well-designed case, this can be the easiest solution to ventilation problems, and will give this device a certain charm to the design of the room.