What is an anti-return valve for an exhaust hood?

Hood — the same familiar attribute of modern kitchens as a microwave, hob, refrigerator and freezer, etc.

For each type of household appliance, an appropriate place is selected taking into account the requirements of the device.

A hood, which frees us from unpleasant odors in the kitchen, requires not only proper placement above the stove.

It is important to correctly install its air duct to ensure reliable operation.

And this is where many consumers first encounter the concept of an anti-return valve.

Let's talk about this element so that you understand what it is and why the part is installed in the device.

Anti-return valve in the hood

Concept

Anti-return (or check) valve — This is an additional part, usually in the form of a grille, which is specially installed inside the duct pipe.

Made from plastic or metal. Requires regular cleaning during use.

Purpose of the part

The main purpose of the hood — removing unpleasant kitchen odors. The device not only catches them, but literally collects them and draws them into itself. And then through the air duct it leads outside the room.

The air duct is sometimes mounted in a window. But most often it is built into the ventilation duct. It is a must have in every kitchen.A decorative grille is used to separate the channel from the interior. It is instead that the air duct pipe is inserted.

However, there may be cases when the air stream changes direction. And instead of moving from the room to the ventilation, on the contrary, it enters the apartment from the ventilation duct.

The reason for the change in direction is the resulting reverse thrust. It may appear, for example, due to strong wind.

Important: the main task of the anti-return element — neutralization of reverse draft, protection of interiors from cold air and unpleasant odors from the street or from the ventilation shaft.

Types of anti-return valves

Various types of return elements are installed in exhaust devices.

• Membrane — a special protective film that allows air to pass through only in one direction: from the kitchen.

• Blinds (petals) — several plates, the structure of which is similar to window blinds. In the absence of reverse draft, the plates can be horizontal, allowing air to pass between them. And with it, take a vertical view and block the access of street air.

• Bivalve (butterfly) — two doors that close and open.

They use different methods of actuation. The grille may close under the mechanical influence of an air mass from a different direction. It is also possible to control it using an electric drive.

Is it necessary to install an anti-return valve?

When purchasing a hood, many buyers cannot decide for themselves whether they need this part. Perhaps the installer is imposing a service they don’t need?

To decide, let's turn to the advice of professionals. They give the following explanation. Necessity of an anti-return valve

is determined individually in each specific case and depends on the characteristics of the air duct fastening.

• If it the pipe has a simple direction in the form of a straight line, check valve necessary!
• If this the pipe has turns, That you can refrain from installing the valve. The reverse thrust in this case will be extinguished by these angles and turns. In this case, the grille can be installed additionally, but you don’t have to do this.

We conclude: check valve — an additional way to ensure clean air in the kitchen. Now you can make the right decision whether your device needs such an add-on.