The need to install a ventilation check valve

The main function of the ventilation system is to remove dust and excess moisture from the air. It is also needed to eliminate unpleasant odors that may remain in the kitchen after cooking or in the bathroom. Sometimes contaminated air masses penetrate back through the outlet shaft itself. To prevent this from happening, it is necessary to install a ventilation check valve.

Check valve purpose

It is not uncommon for an unpleasant odor to emerge from the central shaft in the bathroom or kitchen. The air can stagnate due to insufficient natural draft, lack of supply air, clogging of the mine. Sewer odors or gas can escape from neighboring apartments. To prevent this from happening, a valve is installed on the ventilation duct.

Additionally, the product regulates the speed of the air flow passing through it. The valve does not let cold air from the mine into the room and reduces the level of external noise.

Device and principle of operation

Air check valve - a device that is mounted at the outlet of the ventilation duct. It consists of a body equipped with a damper, which can be opened under the pressure of the air flow, and then return to its original position, and a grill.

Valves come in different sizes, so they are suitable for any ventilation system.

The principle of operation of the device is simple: dirty air is removed from the room and presses on the damper, as a result of which it opens. Once the pressure is released, this element returns to its place and prevents dust and odors from entering the house.

Varieties of check valves

Since the hoods are used in every home, they must be equipped with a check valve. The devices differ not only in the material of manufacture, but also in design, shape, and method of opening.

By material of manufacture

The check valve for ventilation in the kitchen or bathroom is made of silicone, plastic, galvanized steel. These materials have the following features:

• Plastic. Resistant to rust and corrosion, quick installation. It is characterized by a long service life and a low price. The disadvantages of such a valve are low mechanical strength and low resistance to low temperatures.
• Stainless steel. Resistant to cold air, durable, has a long service life. It is necessary to install a steel valve if a powerful hood is used that provides high air pressure.
• Silicone. It is usually already built into a commercially available exhaust fan. The element is a thin film attached to the back of the device. Since the silicone plug does not completely cover the fan, it is not suitable for heavy loads.

In a domestic environment, a plastic product will work perfectly. Moreover, it is easy to care for.

By opening method

According to the method of opening, the product can be manual, mechanical and with an electric drive. The first type provides for the presence of a special lever by means of which the damper opens and closes. The disadvantage of the product is incomplete tightness, as well as inconvenience of operation.

The motorized ventilation check valves are switched on together with the exhaust fan. They can be installed if ventilation is forced, and there is no natural circulation.

The automatic mechanical valve is the most common, as it works by the movement of air masses.

By design and shape

Valves for the hood in the kitchen or bathroom are different in shape, it all depends on the ventilation pipe. For domestic needs, round models with a diameter of 100 mm or more are used. Industrial versions can reach a cross-section of 100 cm. Rectangular ducts are often installed on high-performance air ducts.

By design, the following products stand out:

• Single leaf (gravity). The air flow presses on the valve flap and opens it. In the presence of reverse thrust, the plate closes under the influence of its own weight. Such a product is reliable and simple. It can be installed even with a natural ventilation system. The design has 2 versions: the axis position is displaced relative to the middle of the section of the air duct or there is a counterweight inside the device.
• Bivalve spring. Equipped with two curtains that open when air pressure and slam shut under the influence of springs. Installation of such a product is possible at any angle. Good functionality is only ensured with a forced ventilation system.
• In the form of blinds. The product has a gravitational type of action and is equipped with several flaps. The device is compact, it can be placed only on the hole for natural ventilation or on the entire grate. It is more often used for outdoor duct parts.
• Membrane. In this case, a flexible plate is used, the position of which changes under the influence of the air flow. Since the reverse thrust can deform the membrane, it must be equipped with additional stiffeners.

The choice of a check valve depends on the shape and size of the air duct, its throughput and the intensity of movement of air masses.

Rules for the placement and installation of a check valve on ventilation

In order for the installation of the product to be correct, it is necessary to take into account its location in the system. Backdraft formation must be prevented in all ventilation systems and their combinations. If the system has one air intake, a single valve is sufficient.

If there are several hoods, placement is carried out according to the following rules:

• For each branch that connects the main duct and the intake point.
• At the exit from the ventilation system.

Installation is carried out in such a way that there is easy access to the grille. This is necessary for the periodic cleaning of the device from debris and dust, fat deposits. If the damper is installed on an exhaust or fan, then its additional installation on the air duct is not required.

In an apartment building, it is mandatory to install a check valve near the entrance to the mine of the general ventilation system. Since moist air enters it, but the sun's rays do not, pathogenic microorganisms can develop inside the structure. Birds or insects often settle in mines, therefore, it is better to prevent the formation of reverse thrust.

Service nuances

A check valve in a kitchen, bathroom or toilet requires careful maintenance. Dirt, dust and grease are often lodged inside the device. All this does not allow the shutters to fit snugly against the grille and its functionality deteriorates. To clean the product, you need to pull out the inner case, from which the noise trap and filter are removed.

The procedure is carried out during the warm season so that cold air does not enter the apartment. If the device is synthetic, it is enough to wash it with warm soapy water and dry it. At this time, the duct itself is cleaned using a conventional vacuum cleaner.

Ice often forms on gratings located outside in winter.It must be removed, since it prevents the flaps from fully closing. Insulation can be used to soften cold air. If the grill is plastic outside, it will quickly break, so it is better to use the metal version.

Making a check valve with your own hands

There are a large number of check valves on the construction market, but you can make this device yourself, especially if the ventilation duct has non-standard dimensions. For work, you will need a decorative lattice, lavsan film. Manufacturing involves the following stages:

1. Making a sketch. For this, a frame is outlined on a sheet of cardboard. A rectangle is drawn in the center of the workpiece, the width and height of which corresponds to the dimensions of the ventilation hole. A line is drawn from the center of the figure at a right angle downward. An indent of 7 mm is made in both directions from it (top and bottom). These points are connected by straight lines.
2. Preparing the template. Both parts of the rectangle are cut out, leaving the jumper intact.
3. Sash manufacturing. 2 rectangles half the size of a large workpiece are cut out of the film. Fragments are fixed with glue or a construction stapler on the side parts of the frame so that they go over the lintel.
4. Installation of sashes. The product is attached to the wall with self-tapping screws and is located at the end of the ventilation duct. The flaps should open towards the duct.
5. Installing the grille and checking the valve operation.

Making a homemade version of the device is not difficult if you follow the instructions. Installation of such a product will ensure the normal functioning of the ventilation system, as well as prevent contaminated air and dust from entering the room in the event of a back draft.