The ventilation outlet of the sewer system is designed to allow air to enter the rarefaction zone, which is formed every time the water is drained, to eliminate unpleasant odors and noise. An air valve for sewerage can replace a classic device, a fan pipe, and at the same time does not have the typical inconveniences associated with the operation of the latter, including icing and narrowing of the outdoor outlet in the cold season, as well as the likelihood of unpleasant odors entering open house windows.
An air sewer valve is a body whose diameter corresponds to a similar pipe parameter (hence, the flow parameters in it are identical), equipped with stem or diaphragm covering the outward-facing inlet.
At rest, the pressure existing in the pipeline keeps the stem or diaphragm in the closed position, "pressing" them from the inside. While the flow rate increases when the water is drained, a vacuum is formed in the pipeline, the valve or membrane opens, letting in the amount of air necessary to equalize the pressure. When the parameter is normalized, the closing device returns to its original position.
Important feature: The return flow of air with an unpleasant odor from the sewer system to the living room is excluded due to the pressure difference during the period when the hole is open. Air cannot move from a low pressure zone to a high pressure zone.
There are also combined models that work both for air intake and for its release. The place of installation of such devices must be carefully considered, it is not always advisable to place them in the bathroom or in the toilet, it is possible to take them out of the living quarters or install them in a special block.
Types of air valves
It has already been mentioned above that structurally, air check valves for sewage can have a membrane or a stem. Such models work almost equally efficiently, however, plastic membranes are more prone to wear, they have to be changed periodically.
- Some types of devices can be installed on only one drain point (sink, toilet bowl, etc.). These automatic devices are characterized by a small throughput.
- The air damper for sewerage 110 mm can be mounted on a common riser, thus providing ventilation for several sewer pipes at the same time.
- Combined models are universal and have the advantages of products of both the first and second categories.
Obviously, local (designed for one pipe) models have a smaller diameter than those capable of providing ventilation for the entire system. In most cases, DN 50 mm models are used for these purposes.
According to the installation method, the valve (aerator for sewage) can be:
- threaded,
- flanged,
- coupling.
Equipment installation
An air valve for non-ventilated sewer risers is not the only installation option. Valves can duplicate the classic ventilation scheme, be installed instead of or together with fan structures.
The main requirement when choosing an installation site is to keep the ambient temperature above 0°C. This will avoid freezing and malfunctioning of the equipment.
Height matters a lot on which the installation of an air valve for sewerage is carried out.
- In the absence of a drain for draining water in the floor, the valve is placed 10 cm higher than the location of the highest outlet of a plumbing fixture or water-consuming equipment.
- If there is a ladder, the valve is placed 35 cm above the floor level.
Important: Compliance with these distances ensures that the fan valve is protected from dirt entering it.
It is necessary to choose a place of installation in such a way that it is easily accessible for revision and repair. If the vacuum valve for sewerage with a diameter of 110 mm is supposed to be closed with panels, plasterboard or other structures, it is necessary to provide such structures with special doors or hatches to avoid the need for complete dismantling during repair work.
The place of installation is chosen by the free end of the pipe or its socket.
In some cases, it is advisable to install an air sewer valve in the attic or in a specially designated household room.
After choosing the installation site and purchasing a product that fully meets the requirements and is suitable in terms of geometric parameters (diameter), the valve is installed in accordance with its design (on a thread, in a flange, using a coupling). It is important to ensure the tightness of the joints and check this parameter after the completion of the installation work.
If you are interested in knowing what it is used for, then we also talked about this in another article.
Operation features
The rules regarding the selection and installation of air valves in the sewer systems of apartments and private houses were included in SNiP only about 10 years ago. The decision on the mandatory installation of such a device is made by a specialist, however, it is believed that the use of an aerator cannot reduce the efficiency and quality of the system. In general, this statement is true, but it is important to monitor the condition of the equipment and its serviceability.
Violations can be sticking of the membrane or stem in a certain position.
- If the stopper has occurred in the “open” position, there is a risk of unpleasant odors from the sewer entering the room.
- If the valve sticks in the closed position, it can break the water seals.
At the same time, the simplicity of the design and the high reliability and durability of the equipment associated with this feature, together with timely revisions of the valves, will help to avoid accidents.
Sewer air valve 110 mm mounted on riser Installing aerators together with traditional ventilation outlets or fan fittings virtually eliminates the possibility of a critical change in pressure in the system and the failure of hydraulic seals.
Sometimes a situation arises when an air valve that has worked effectively for several years ceases to “cope with its duties”, although there are no breakdowns or malfunctions. Most often this is due to changes in the operation of the sewer system itself, for example, with the installation of a washing machine that discharges water under pressure. At high flow rates, the pressure in the pipeline changes more rapidly, so it is better to install an additional individual valve on a new unit.
