What is a water seal
One of the necessary and mandatory elements of any plumbing fixture connected to the sewer system is a siphon.
This is the simplest device, a horizontal bend of the outlet set, in which a certain volume of water is always present. This is a water seal for sewerage; it performs the important function of cutting off the volume of the sewerage system from the internal atmosphere of a residential or public premises. As a rule, plumbing fixtures are a kind of bowl with an outlet hole.
The siphon is part of the outlet set and is connected to the drain hole as a separate element. This facilitates manufacturing and installation, and allows you to simply and quickly replace a defective device.
The only device that has its own hydraulic valve as an integral structural element that provides functionality is the toilet. Its siphon ensures waste removal along with the water flow and cannot be installed separately.
Why does a washing machine need a water plug?
The question may arise: why do you need a water seal for a washing machine? It is necessary to ensure that odors from the sewer do not penetrate through the drum. It’s especially unpleasant when you forget to take out your laundry in the evening and find it with a strong sewer smell the next morning.
There is no need for special devices to ensure a water plug between the washing machine and the pipes. It is enough to comply with the conditions for connecting the device. The drain can be organized like this:
- Plumbing fixtures - sink, toilet, bathtub. Such a drain will not have contact with the pipes, that is, the drum will not smell.
- In the sink siphon. For a washing machine, this option is convenient and easy to implement. You don’t have to get to the sewer pipes, because access to the siphon is often easy. The role of the water seal will be performed by the sink siphon, that is, there is no need to install additional elements.
- Directly to the sewer. This option is also convenient, but will require pipes to be installed to properly organize the drain at a level of 60-75 cm from the floor.
Siphon with outlet for washing machine
Operating principle and functions of the water seal
Let's take a closer look at what a water seal in a sewer is and why it is needed. The simplest example that can illustrate its action is a U-shaped bend in a pipeline, in which, according to the law of communicating vessels, there is a balanced water plug. It completely blocks the lumen of the pipe and provides a barrier to the entry of gases into the living space, which are found in excess inside the interconnecting sewer pipelines. Biogas, as sewer gases are otherwise known, contains components that are harmful to health, flammable and simply disgusting:
- methane;
- hydrogen sulfide;
- hydrogen;
- carbon dioxide, etc.
The penetration of biogas is extremely undesirable, and the simplest and most reliable method of shutting off is a water seal. There are other ways to prevent the flow of gases - for example, using household sewer pneumatic valves; in a private house, installing a drain pipe is used. However, these devices are not always effective enough and do not completely eliminate the possibility of bad odors. Therefore, a water seal for sewage is always used in conjunction with any additional devices.
Types of water seals
There are different designs of water seals that work on the same principle, but are implemented in different ways. The following types are common:
Knee
This is the same U-shaped design option, the simplest and most reliable. The crank lock can withstand significant loads. The length of the water column is large enough to ensure the shut-off of pressurized biogas or to carry a burst discharge of large quantities of wastewater. Most often, knee traps are installed under bathtubs, showers or dishwashers. In addition, the toilet and bidet designs also contain knee water seal options.
Example of corrugation and U-shaped version
Bottle type
This design is familiar to anyone who has had to look at a siphon under a kitchen sink or bathroom sink. It is a plastic container that includes a vertical drain pipe. A drain pipeline connected to the sewer comes out of the tank on the side. The vertical inner tube is immersed so that its cut is below the level of the side outlet. This design not only provides a reliable water stopper, but also forms a container for food scraps and other organic waste. When it is full, the outer part can be opened by unscrewing the cap from the bottom and the container can be cleaned. Bottle siphons are made of polypropylene and are less durable than elbow designs. The threaded connections are unreliable, which requires fairly frequent replacement of the siphon.
Double-turn water seal
Another name for such a siphon is a pipe siphon. It is a slightly more complicated version of the knee type, equipped with a removable knee or inspection hatch in the upper part of the bend. A double-turn water seal in the sewer system is found in old houses, industrial enterprises and other premises where the internal sewage system was installed a long time ago. Currently, this design option is rarely used, since the configuration of bathrooms does not allow its use.
Corrugated siphon
The simplest option, which is a flexible corrugated pipe, bent in the shape of an elbow and connected with a plastic clamp for immobility.
The design is very simple and can be done by hand. However, the inner surface of a corrugated pipe is poorly cleaned of small debris, hair, organic particles and, in particular, heavy particles - sand, cement chips, etc.
The hydraulic valve in the sewer, made of corrugated pipe, requires constant attention and frequent cleaning, which creates a certain inconvenience for the user. At the same time, such a tube can be purchased separately and simply replace the problematic element. It is inexpensive and can be found in any plumbing store. Before making a water seal for sewerage from a corrugated pipe, you should install a grill on the drain hole to protect it from small debris.
Water seal for storm drainage
This refers to non-industrial storm sewerage, which ensures the removal of rain or melt water. We are talking about the internal variety - all sewer receiving devices that are located at floor level are also called storm drains. These are funnels or drain holes in shower rooms located in the concrete floor screed. This group also includes drain holes in saunas or baths, swimming pools, etc.
They are distinguished from industrial stormwater systems by the type of wastewater - basically, it is ordinary water without large and solid particles. A feature of such siphons is their small size, forcing the use of bottle-like structures. To clean, lift the top grill, which protects against the entry of foreign objects.
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DIY installation
Installation may require:
- adjustable wrench,
- screwdriver,
- fum tape,
- silicone sealant.
Installing the shutter under a sink or sink is simple:
- we fix the pipe and the grate , which will protect the sewer from large debris (you can read about maintenance of Topas septic tanks with your own hands in this article), in the hole of the sink using a fixing nut;
- put a siphon on the drain pipe and secure it with a locking ring.
If the sink has two drain holes, install a valve with two entrances.Connecting dishwashers (how to supply water to a private house from a central water supply) is carried out through special models of siphons;
- Using a hose, connect the outlet pipe to the sewer.
The elements are connected hermetically using O-rings and silicone sealant.
Attaching water seals:
- toilet,
- urinal,
- baths and showers - carried out in several ways, depending on the supplied pipeline.
Toilets are connected using plastic pipes or corrugated pipes. Sealing is carried out using sealant or cement mortar.
Installation of siphons with overflows is carried out similarly to devices without overflows.
The overflow hose is connected to a tee pre-mounted on the pipe.
Possible problems
When operating an internal sewer system, we pay attention to several points that can cause an odor to appear and the hoses to break off from the siphon pipes:
- the shutter is constantly filled with water .
With rare use in a country house, the water evaporates and nothing prevents odors from entering the room; - periodic disassembly of the siphon require careful checking of connecting elements.
Lock nuts become loose, O-rings dry out and crack.This causes leaks and unpleasant odors;
- pressure drops inside the sewer .
The water layer, in this case, is squeezed out into the sewer, and the valve stops functioning; - formation of rarefied space.
The problem occurs when the pipes are incorrectly selected.The volume of drained water completely covers the diameter of the pipe, and a vacuum is formed behind it.
In the latter situation, it is possible that the sewer connection will rupture (what kind of coupling is needed to connect corrugated sewer pipes is described in this article) and the valve may break or the entire siphon will break.
In addition to the wrong diameter, this can happen when:
- no slope,
- appearance of blockages,
- icing.
ADVICE! When using siphons, fine sediment accumulates at the bottom of the flasks or hoses.
This can be avoided by using a fine mesh screen over the sink drain.
Do it in the bath
The installation of sewerage in a bathhouse is carried out according to the same principles as in a residential building.
The design of the dry shutter deserves special mention.
Irregular use of the bathhouse leads to evaporation of the water layer, possibly causing the water to freeze in winter.
There are two types of such valves:
- float,
- pendulum
The float device implies a top drain.
In operation, the water layer lifts a special plastic float, and the shutter works like a type of water seal.
When the water evaporates, the float lowers , reliably blocking the drain hole.
The pendulum type has two plastic curtains that close the drain hole under their own weight.
The flow of water opens the curtains.
Any of the dry valves contains in its design elements of a classic siphon.
The name “dry” comes from the ability to block odor in the absence of a water layer.
Dry water seal
There is another type of siphon - a dry drain, or, as it is sometimes incorrectly called, a dry water seal for sewerage, since a water seal cannot be dry by definition.
It also provides a shut-off feature for biogas and also acts as a check valve to prevent wastewater from flowing backwards. This is a useful function for residents of lower floors, who may experience this phenomenon when the sewer riser in the basement is clogged.
In addition, the design of the dry siphon makes it impossible to break the water seal. This may be due to rare use of plumbing, high pressure inside the system, or, conversely, strong vacuum due to the draining of a large volume of water.
A dry siphon for sewerage can have different designs:
- membrane _ One of the simplest and most reliable options, the basis of which is a tubular membrane that opens when water passes and closes again when there is no water;
- float _ It is a compromise design option between the dry and hydraulic options. You can make it yourself using a tennis ball. When water passes, it deflects, after which it floats up and blocks the drain, preventing the reverse movement of liquid and gas;
- pendulum _ It is a kind of gravity valve that allows drains to pass through and closes the passage again under the influence of its own weight.
membrane
There are also more complex structures with molecular memory, high-tech and expensive devices based on the elasticity of materials and the ability to return to their original position after deformation.
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How to make a dry shutter at home?
To make this device with your own hands, you will need a plastic ball and a gasket. The diameter of the ball should be slightly larger than the drain hole. The plastic ball must be placed on the drain hole. Next, you should secure it along the edges. The ball must be securely fixed. To do this, it is recommended to put a gasket on the pipe - it will securely fix the ball in the pipe. The height of the wall above the level of the sewer pipe must be at least 5 cm. When the system is in use, the ball floats up and water flows freely into the sewer. During inactivity of the structure, the ball will lie on the drain hole and block the path of sewer gases.
How to choose
The choice of siphon design is influenced by various factors:
- sewer pipe diameter;
- size and availability of space to place the device;
- material and availability of additional connecting pipes;
- presence (or need) of overflow.
Water seal for sewerage 50 is necessary for bathtubs, washbasins, kitchen sinks, dishwashers or washing machines. The horizontal pipeline for these devices has a diameter of 50 mm, sufficient to drain wastewater from these devices. For toilets, risers, or in other situations, a water seal for sewerage 110 is required, designed to cut off a large pipe diameter and with the appropriate dimensions. 110 mm pipes are usually used for the vertical part of the system. A water seal on them is possible only in the lower, basement part, as a cutoff from biogas from an external system or its own treatment plant. As a rule, the choice of such elements is made at an early stage, while the house is still being designed. The main selection criteria are reliability, ease of installation and low cost of the device.
