What is the function of the air valve for sewage
Quite often, with the simultaneous use of several plumbing fixtures, an unpleasant smell breaks out from the wastewater system into the room. To solve this problem, an air valve for the sewage system is installed in the drainage structure. This simple device effectively neutralizes pressure drops in the system, eliminating the cause of gas intrusion through the siphon seals.
The cause of the penetration of unpleasant odors from the sewer system
All plumbing fixtures (sink, sink, toilet, shower, washing machine - automatic) are piped to one sewer riser, the lower part of which is connected to a collector that drains the waste to the central sewerage system.
There are two main options for the design of internal sewage systems:
- The sewer riser can go out into the attic or out above the roof, while remaining open. This design maintains atmospheric pressure within the structure.
- The fan riser may not be available (non-ventilated sewerage).
What happens if the top of the waste pipe freezes up, gets clogged with debris, or has an unventilated drain in the house? When the water is drained, a vacuum is created in the system, which draws water out of the “weak” water seal of the siphon, creating a cotton. As a result, unpleasant odors from the drainage system freely penetrate the room. The drain valve for the sewerage balances the pressure in the system, excluding the possibility of breaking the hydraulic seals.
You should be aware that in the specialized literature, the sewer ventilation valve can be called differently: fan, vacuum, air check valve, aerator.
Design and principle of operation of the device
The vacuum valve-aerator consists of the following elements:
- Housing with a hole through which air enters the system. Body material - PVC.
- A cover that provides access to the internal elements of the device.
- Diaphragm stem.
- Rubber seal that ensures the tightness of the structure.
The principle of operation of a vacuum valve for sewage is extremely simple. When the pressure in the riser is equal to atmospheric pressure, the valve membrane is pressed firmly against the body of the device. The sewerage system is sealed. When a vacuum occurs more than 0.007 kg / cm2capable of breaking the water seal, the membrane opens the passage for atmospheric air into the system, the pressure is equalized, the valve closes.
The design feature of the ventilation valve for sewage is the location of the membrane. In working condition, the device passes air only in one direction: from the room to the sewage system. The valve is triggered almost instantly. With proper calculation and adherence to the installation rules, the use of these devices guarantees the protection of the fan system from pressure drops.
Specifications and manufacturers
The main technical characteristics of the air check valve are:
- outer diameter, which is selected in accordance with the section of the sewer pipeline;
- air consumption per unit of time.
The modern plumbing equipment market offers drain valves of three standard sizes, corresponding to the diameter of the drain pipeline: 50; 75 and 110 mm. The use of air valves for sewerage in systems with a pipeline of a smaller diameter (for example, 32 or 40 mm) requires the use of special adapters. Some models are initially equipped with a stepped pipe, which allows the device to be used in various sewer systems. Valve performance varies depending on model and location. Devices with a flow rate of 7 to 37 liters of air per second are offered for sale.
Today, the most popular manufacturers of ventilation valves for sewage systems are:
- Europlast (Ukraine);
- Wavin (Poland);
- McAlpine (UK);
- HL (Austria).
Advantages and disadvantages
The valve for the sewer riser has a lot of advantages, among which it can be noted:
- Prevention of situations of breakdown of hydrazers, which provides protection against the breakthrough of unpleasant odors from the fan system into the room.
- The possibility of creating a sewerage system without installing a waste pipe, which greatly simplifies the design and reduces the cost of the wastewater disposal system.
A serious drawback of this device is the possibility of leakage due to natural wear of the seal and contamination of the membrane.
It should be understood that the installation of a sewer ventilation valve in the fan system of an apartment building requires an accurate calculation of the number of devices based on their throughput.
Air valve for sewage: installation rules
The vent valve is installed on the drain pipe or on a specific device. Depending on the diameter, the device can be positioned as follows:
- Valve with a diameter of 110 mm, designed for installation in the upper point of a sewer pipe. During installation, it is important to ensure that the valve is located 500 mm above all drainage points.
- The sewer vacuum valve with a diameter of 50 or 75 mm is designed for installation after siphons of sanitary fixtures.
The design of internal sewage systems is regulated in accordance with SP 30.13330.2012
Installation of a ventilation valve requires a number of rules to be followed.
- The valve should be easily accessible for repair and maintenance.
- Correct operation of the device assumes free access of air to the membrane.
- If the installation is supposed to be on a drain pipe, then at the place of valve installation (for example, in the attic), a positive temperature should be ensured.
If the drainage in a private house is carried out into a septic tank, then the presence of a fan pipe for ventilation of the drainage system is mandatory. Air valve for septic tank installed to supply air to aerobic bacteria involved in the processing of sewage. The ventilation valve is installed at the top point of the drain pipe, as an additional protection preventing the breakdown of the hydraulic seals.
In a residential building of a multi-storey building, an air sewer valve is installed on any vertical section of the drainage system. For this, a tee is built into the horizontal structure, into which a vertical pipe with a valve is installed. Installation is carried out as follows: in the presence of a drain - 350 mm above the floor level; in the absence of a ladder - 100 mm above the taps from plumbing fixtures. The distance from the device to the nearest siphon should not be less than 200 mm.
Stages of installation work
Recently, to create intra-house sewer systems, they have used plastic pipes of various diameters. Based on this, the material of the air valves is selected - PVC or polypropylene.
Consider installing a ventilation valve behind a toilet siphon:
- Dismantle the horizontal section of the pipe on which the ventilation valve is to be installed.
- Install the aerator in an upright position in a branch or tee.
- Install the tee in the pipe section.
The tightness of the joints is ensured by sealing rubber bands, which must be installed in the connected elements of the system.
Additional security measures
Possible breakdown of hydraulic locks is far from the only problem that arises during the operation of an in-house wastewater drainage system. To provide additional protection against flooding, check valves are installed in tandem with ventilation valves.
These devices differ in the design of the working mechanism:
- Ball. The shutter element is a movable ball that blocks the flow through the valve during the reverse movement of wastewater.
- "Clapperboard". The flap valve for the sewer is equipped with a plug, the action of which coincides with the direction of movement of the wastewater. If there is no flow, the valve is closed. With the reverse movement of waste water, the plug takes place in the "seat" of the valve, reliably blocking the through hole.
- Disk. A steel disc inserted into a rubber holder acts as a shut-off mechanism for a check valve of this design. With the reverse movement of sewage from the sewerage system, the disc moves and closes the through hole of the device.
Among the presented types of non-return valves, the most popular are “crackers” (not to be confused with the anti-cotton valve installed on the LPG of a car). When installing them in the sewage system, follow the manufacturer's recommendations, since various types of valves are designed exclusively for horizontal, or only for vertical sections of the pipeline.