Sewer check valve is leaking. Check valves for sewerage (photo)

The sewerage system is an integral element of the communication of a residential building. Thanks to the centralized removal of natural waste, residents do not have to worry about how to get rid of waste products.

But, unfortunately, a violation of the rules of use can lead to the fact that in the pipes, as a result of which everything that needs to be removed will end up in the apartment. A check valve for sewerage will help to avoid such trouble.

Device

The valve serves to perform the following main functions:

1. Prevention of sewer contents from entering the dwelling.
2. Blocking the access of an unpleasant smell from the communication system.
3. Reducing the likelihood of pests and insects entering the house through the sewer pipe.

The device works on the principle of preventing the output of everything passed through itself back. Its device allows you to block the rise of liquid as a result of blockage. If it does not exist, this situation threatens to flood the residents of the lower floors. It makes sense to install a check valve not only in an apartment building, but also in a private house.

Principle of operation

When sewage tries to go in the opposite direction under air pressure, the path is blocked for them. To do this, the device is equipped with the following components:

1. Membrane. Blocks the lumen of the pipe.
2. Lever arm. Serves for a conclusion of waste in the necessary direction.
3. Lid. It can be used to remove blockages and dirt.

Requirements

1. The design should be simple and easy to self installation and service.
2. Shutting off the sewer pipe in case of blockage should occur automatically.
3. Possibility of manual adjustment in case of emergency.
4. The material from which the device is made must be of high quality, since the environment with which the interaction will be carried out is caustic and aggressive.
5. The membrane must reliably cover the lumen of the pipe in order to exclude the possibility of foreign odors entering the living room. As well as pests and insects.

Kinds

Despite the simplicity of design and a similar list of functions, sewer check valves are divided into different kinds depending on one criterion or another.

Material Differences

Products can be made:

1. From plastic. Most often, plastic fixtures are purchased for an internal sewer pipe in a residential area. They are easy to install and dismantle, the cost of such products is low.
2. From cast iron. Such strong and durable devices are usually used on pipes of an external sewer system. They are much more expensive than the previous ones, but the service life is incomparably longer. Usually such valves are provided for installation on pipes of considerable diameters.
3. From stainless steel. Material resistant to the damaging effects of wastewater.
4. From bronze. The most expensive material, but at the same time resistant to aggressive environments and having a long service life.

Depending on the design features, sewer check valves are:

Air

Main destination:

• preventing foreign odors from sewer pipes from entering the living room;
• maintaining optimal air pressure in the system.

Principle of operation: when sewage is discharged into the sewer, the membrane opens to give them the way, and then, under air pressure, it returns to its place, blocking the return path.

Signs of a malfunctioning air valve:

• there was a smell of sewage in the room;
• during the drain, extraneous sounds are clearly heard.

vacuum

These devices are indispensable in residential premises, in which other external structures for adjusting and normalizing air pressure in the sewer system are not provided.

In addition to the membrane and the housing itself, vacuum devices provide for an air intake chamber, which plays the role of a regulator of the amount of air:

• at high blood pressure excess air is automatically removed from the system;
• when lowered, the membrane is affected, as a result of which it lowers and opens air into the pipe.

The special role of the vacuum valve determines the peculiarity of the installation - it is installed on the highest section of the waste pipe.

Ball

These products got their name due to the fact that the tube lumen is locked by a ball (rubber or metal).

Operating principle: at the moment of draining, rarefied air is formed in the system, which releases the ball from the pipe, giving way to waste. Then the pressure builds up and the ball returns to its place, preventing the return of waste masses.

The spherical design appeared one of the first and today is considered perhaps the most reliable. That is why it is so actively used in the external sewer systems of apartment buildings, where the flow activity is highest.

Reception

These valves have a special purpose - they are used to prevent the leakage of liquid produced in the process of pumping and distillation (for example, the extraction of water, oil and other liquid resources). Accordingly, such devices are not used in residential buildings.

Wafer

They got their name due to the fact that they are installed between the constituent elements of pipes - flanges. Accordingly, their installation is carried out already at the stage of laying pipes, since they slightly increase its total length. Typically, wafer valves are made from the same materials as the pipes themselves. This is done for stability and durability.

Operating principle: the device contains a flap (one or two), which, under the pressure of rising wastewater, occupies a horizontal position and blocks access to the pipe lumen. When the level of sewer masses decreases, the sash returns to its original position.

Most often, such devices can be found in the sewerage system of apartment buildings and industrial buildings.

Varieties of sizes

When choosing a specific check valve size, it is necessary to be guided by the diameter of the pipe for which it is intended to be installed. Accordingly, the dimensions of the products are in the range from 32 to 300 millimeters.

Installation rules

Before starting the installation of the device, you need to consider the following points:

1. Find out the diameter of the pipe on which the installation is supposed to be. It is better that the valve clearly matches the size of the communications, because otherwise it may be difficult to remove wastewater.
2. When choosing a particular type of valve, it is important to consider the material from which the pipeline is made.

   For example, on a plastic pipe, installation is possible in almost any part, since the plastic can be easily cut in the right place. But with metal pipes the situation is more complicated, since, for example, a wafer valve can only be installed between the constituent elements.

3. Particular attention should be paid to the quality of the materials of the product. The higher it is, the longer the valve will last, and the better it will fulfill its purpose.
4. The installation site must be easily accessible.
5. Before installation, make sure that the valve is tight.

Where can I install

When choosing an installation location, the following options are available:

1. You can purchase one check valve that matches the diameter of the common sewer outlet pipe and install the device on it. Most often, this option is chosen by residents of private houses.
2. It is possible to equip the communication of each plumbing facility. It is this method that is recommended in apartment buildings, as it reduces the likelihood of emergencies.

Do-it-yourself installation

Necessary materials and tools

In order to install the valve on internal plumbing communications, the following is required:

1. Pipe cutter.
2. the valve itself.

Walkthrough

Installation procedure:

1. Choice of installation location. It must be within reach to quickly eliminate possible problems that arise during operation.
2. It is necessary to warn the neighbors that sewerage work is planned so that they do not use it for an hour and a half.
3. Water access is blocked during installation work.
4. Depending on the size of the valve, you need to measure the required distance on the pipe section and use a pipe cutter to cut out the excess section.
5. The valve is placed in the resulting niche and secured with a coupling or with a thread. On some models, an arrow is drawn indicating the direction of water flow. It should be directed towards the public sewer.
6. The installed device needs to be checked. When draining the water, there should be no extraneous sounds and odors.
7. Installation must be completed within two hours so as not to create problems in the operation of the common pipeline.

Price

What it depends on, pricing examples

First of all, the cost of the product is affected by the material from which it is made. In second place are the design features and diameters of the device. The manufacturer of the device also matters:

• so, for example, a plastic vacuum check valve will cost from 350 to 600 rubles;
• a ball of medium diameter made of cast iron will cost an average of 3050-5800 rubles;
• flangeless stainless steel - about 1200-2300 rubles.

A non-return valve for sewage is a special shut-off device that ensures reliable closure of the through hole in the cavity of the sewer system.

The main purpose of the shutter is to prevent the movement of drains in case of blockage and overflow of the network.

Throttle installation is required:

• In the sewer in an apartment building, on the ground floor, in the basement.
• In a private house located on a site with a high level of groundwater.
• When installing the system, if all the rules for laying the pipeline were not observed.
• As a safety option in any stocks.

Shutoff valves are also involved in resisting cockroaches and rodents that can enter the house by moving through pipes. The shutter is always in the closed position and opens only when water from the plumbing fixture enters the drain.

During the introduction of the device into an existing sewage system, there are some difficulties with shutting down the system and connecting the pipes in series, so the installation of the valve must be provided during the initial laying of the pipeline.

Views of how devices work

The sewer check valve is of several types. Depending on the installation location and the nature of the network.

1. Swivel, they are also called petal (crackers).

The body is square or oblong with a socket connection on one side and an idle end on the other. Inside, a round washer with a diameter larger than the pipe bore by 2-4 mm is attached to the upper part of the wall.

A light spring is installed at the fastening point, which allows you to cover the passage more tightly.

In a calm state with horizontal installation, the cracker is closed and opens when drains from plumbing fixtures enter the system. If there is a blockage, overflow and water rushes up, the throttle closes and blocks access.

In some models, a manual water seal of the same principle of operation is additionally installed. It is located on the same line, just after the first one. Its task is to mechanically block the passage of drains if the first sewer valve does not work.

2. Lifting.

The main element blocking the passage is also a round disk. It is attached to the ceiling of the case with a bolt, a metal spring is wrapped around it. It creates tension to keep the membrane closed. The pressure of the water entering the system is enough to lift the spring washer and move on.

The throttle device allows you to stop the reverse flow, which presses down on the disk. The design is used in any sewerage system. hallmark The structure of the body is the flange connection of the top cover. By unscrewing it, you can easily clean and repair the device.

3. Ball.

Installed only on internal networks. There are special recesses inside the case: water passes into one, and a ball is placed in the other. During the movement of drains from the device to the receiver, the ball rolls into the cavity.

If the process occurs in the opposite direction, the ball blocks the passage.

The shutter has one drawback. There is no clean water in the sewer, which means that drains are always mixed with dirt and sewage. Debris can get between the ball and the wall of the device and it will leak.

4. Wafer type.

Mainly used in plumbing systems. Due to their compactness, of course, they outperform crackers, but the installation conditions are very tough.

The breather is mounted between two flanges and when opened, its movable part must go inside the pipe.

A wafer choke is a metal cylinder, inside of which a disk with a spring is fixed along the axis. The plate is always closed and opens when pressure is applied. The peculiarity is that the working pressure in the sewer is less than the water supply. Therefore, drains cannot push through the spring.

The listed shutters are only mechanical, with the exception of lifting and petal, they are electric. In addition to the revision, a motor is installed in the top cover, which works after the sensor signal, and the clapperboard closes automatically. And also airy from the smell.

Check valves for sewerage differ in color. This is necessary to determine the location of its installation. In external use, it is made brown, in internal use it is gray.

The dimensions in the table are approximate, as each manufacturer produces different products.

How to install yourself

At the time of design, the risk of flooding should already be invested in the system, so during this period it is necessary to work out the installation of the shutter. Installation takes place in several stages.

The check valve can be installed both on an external system and on an internal one.

The first stage is the choice of installation site

The place for installing the throttle must be easily accessible. It is impossible to mount the equipment in the wall and in the floor, close it and clutter it up.

Each device has a cover for cleaning and repair, so access to it is necessary at all times. If the sewer runs in the floor or concrete base, the locking mechanism is mounted in the pipe, and its upper part remains on the surface.

If the depth of the gasket is large and the headband is out of sight, we make a removable cover in the floor for revision.

The second stage is the choice of the device

Locks are classified differently, some are installed on the street, in a well, others are to be installed only indoors. It is necessary to choose the most suitable one for the installation conditions. If you make a mistake at this point, the shutter may subsequently collapse, crack.

Tools:

1. Bulgarian with a cutting disc.
2. A sharp hard knife for chamfering.
3. Oil, paste for lubrication.
4. Hammer and flat board.

• At the installation site, we clear the space for work.
• We measure the length of the device so that it fits into the prepared space.
• We generously lubricate the end of the pipe with engine oil or plumbing paste.
• The sealing ring should also be processed.
• Before inserting the cracker into the pipe, having made the socket, we will turn the device several times (if possible).
• With a little effort, but sharply, we stick the pipe into the throttle.
• Then we check if the rubber band in the device has pulled up.
• FROM reverse side we continue to assemble the sewerage system.

It is not always possible to install a throttle during the initial installation of the pipeline. This can be done in the current system as well.

• Having chosen a place, carefully cut out a piece of pipe with a grinder. It is advisable to choose a place closer to the socket so that the piece can be removed.
• We make a pipe segment a little larger than the device itself. In order not to disassemble the entire thread, we need a channel with a compensatory socket.
• We insert the compensator into the pipe, and the shutter from the other end.
• We insert the assembly onto the pipeline, first from the compensator side, moving it until it stops, then, pulling it out of the socket, insert the shutter - from the other side.

Important: each cut point in the pipe must be processed by chamfering.

How to chamfer a plastic or PVC pipe

The end, if it is not fixed in the system, we pull it out and press it between the legs or armpit so that the cut is in front of the eyes. Using a sharp knife, we begin to cut the edge in a circle. It turns out a chamfer, a cone. We also remove all burrs in the cut points.

How to put at the outlet of the plumbing fixture

To install to the toilet, you will need an external device without a stable case, inside which a clapperboard walks. Instead, a cuff is put on the back of the toilet, at the end of which a solid membrane is fixed. Conical shutter. Serial connection allows you to stick the device inside the socket, where the plate will work. We coat each joint with oil or plumbing paste for better attachment.

Correct and incorrect placement

Each device, open or closed, has a direction of movement of drains drawn on the case. Indicated by an arrow or a triangle. It is in the direction of the water that a water seal is installed.

The shutter works only in one direction and in different positions: whether it is a vertical or horizontal arrangement of the device. If all installation conditions are met, in the first minutes it will be seen that the device is functioning and water passes through the membrane.

The correct position of the device is still determined by the method of installation. From the socket to the idle end (that is, into the socket), only the empty end of the pipeline can be inserted. On the other hand, only the connecting expansion of the pipe with sealing rubber.

Incorrect location threatens with constant problems with the device. A device that is not installed according to the scheme or in the wrong place will immediately show its failure. Any work begins with reading the instructions, the installation of the codpiece is no exception.

Difficulties that may arise from improper installation:

1. Hard to reach place. The device requires constant monitoring after installation, so if the valves are in a corner or under a layer of concrete in another inaccessible place, it is not possible to service them.
2. The device was installed in violation of the technological process. Leaky joints, constantly leaking covers - shutters are an unpleasant sight. If the rubber bands in the socket are not lubricated with oil during installation, they will bulge or fall inward. Even when all joints are attached to each other point-blank and tight, they can leak due to the rotation of the o-rings.
3. You can not install the throttle immediately after the rotary part of the system. During the movement, the drains gain a decent speed, which means they create pressure. The pipe clogged or failed to cope with the reverse flow, and the valve closed. Immediately the problem was not detected, and the water continued to flow from the plumbing fixture. The flow of water, approaching the membrane, will receive resistance and can knock out the outlet from the connecting joint. Therefore, the device is installed strictly on a straight section.
4. Wrong valve installation direction selected. Any device has a water movement indicator, according to this figure, installation must be carried out. If the device is turned upside down or put down with the lid for revision, the unit will stop working.

How to clean, audit

By itself, it excludes the passage of clean water through it. Sometimes debris does not pass through the valve, getting stuck at the base of the cheeks of the plug. This problem often occurs if you do not monitor what goes into the drains.

Manufacturers of hydraulic seals have provided an inspection window in the device. It is located at the top of the shutter. Mounted on several bolts: three or four. Cleaning or inspection of the units of the unit occurs through it.

We unscrew the bolts, after loosening each one. Remove the water seal cover. A circular membrane and a chamber through which all the water passes will become visible. Remove all debris and large items stuck in the chamber with a glove. We slam the plug several times, shaking it off. Now you need to rinse the device.

Clean water is poured inside the window. First, the chamber is washed after the membrane, then the inlet compartment. We check the normal operation of the throttle after the revision by flushing the toilet or turning on the water in the sink. All this without closing the viewing window cover. You can see how everything works in it. Only after that close the cover and tighten the bolts. The gum also needs to be washed and returned to its place.

Important: you can not immediately pull out all the studs and remove the cover. Residues of drains can quickly gush through the window.

Popular brands and specifications

"Tatpolimer"- a commercial and industrial company, in the price list of which there is a check valve for sewerage TP-85.100. The stop valves are made of polypropylene. Diameter 110 mm, there is a manual damper control knob. Operating temperature up to + 60 degrees. Withstands water column pressure up to three meters. Purpose - household sewerage. The minimum service life is 40 years.

"Peshtan" is a Serbian manufacturer of fittings for engineering systems made of polypropylene and PVC. The product of this company is made of polyvinyl chloride. Painted in light brown. Applicable for systems outdoor sewerage as well as inside buildings. It has a manual damper control function. Suitable for pressurized systems. The diameter of the passage hole is 110 mm, the material of manufacture is polymer. The service life of polymer products is over 50 years.

Ostendorf– Germany. Reliable and durable valve made of polypropylene. Tube diameter 50-160 mm. Depending on the purpose, it is gray and brown. Gray with a diameter of 50 mm, only for internal systems. Operating temperature up to +95 degrees. Manual control - a membrane using a rotary flag on the cover. The bolts on the cover are made of stainless metal, easily unscrewed in an aggressive environment. The sealing gum in the socket of the product has a special conical shape, which allows it to sit firmly in the groove and not rotate.

Useful video

Details about the unit:

Install by yourself:

Both for residents of multi-storey buildings and for owners of private buildings, protection against unexpected leakage of the sewage system plays a huge role. The check valve for sewerage is used specifically for the safe operation of the plumbing system.

A non-return sewer valve is a device that prevents the reverse flow of water into an apartment or other room. This often happens when drains are clogged, because water always moves in the direction where there is no resistance. If a blockage forms in the pipe that prevents the normal flow of fluid, then the flow of water simply turns in the other direction. In the event that a blockage forms in the communication, but the movement of water does not stop, the flow can simply flow in the direction of the sink mixer, toilet bowl and other consumer outlets.

Photo - vacuum model

What is the installation of a check valve on the sewer:

1. In order to protect the dwelling from the smell from the sewer. In addition to protecting your belongings and home from flooding, constipation protects you from unpleasant sewer odors. Very often, an additional air vacuum valve is used, which forms a kind of bubble that holds the stench. At the same time, thanks to the same ventilation, fresh air enters the sewer, providing a kind of circulation of flows;
2. To protect the internal and external sewer system taps;
3. To protect storm water and drainage systems from leaks and breakthroughs;
4. For the safety of consumers of water supply in an apartment or cottage ( washing machine, shower cabin, sink, sink, hose, etc.).

Kinds

The device comes in several varieties:

1. Membrane (KESSEL, McAlpine for fan pipes);
2. Lever or ball (Redi);
3. With lid (Karmat);
4. Cast iron and metal flanged.

Membrane works due to a special membrane that opens the duct in only one direction. If the water starts to flow in the other direction, the diaphragm will bend, but the leak will not form. This will hold the fecal or water flow for some time, but it cannot be used as a permanent method of protection - with a strong pressure of the water flow, the diaphragm may not withstand. The system is used more often in pressure sewerage, since the diaphragm cannot withstand strong pressure.

Photo - cast iron valve

The membrane valve for sewerage is 50, 110 mm or more, it can be double-leaf and single or spring. Such plumbing is not equipped with a plastic or rubber membrane, but with a metal one, which provides more reliable control of the back pressure of the pipe. It is recommended to put it on communications with strong pressure, but where it is not possible to equip other types of constipation.

Photo - air fungus

The lever-type device works by means of a handle and a locking mechanism, like a ball valve. The principle of the system is very simple. When the handle is turned, the ball (locking mechanism) rotates in a certain direction, closing the duct. In addition, there are models equipped with a spring or electric drive. Mechanical and electrical taps are often used for a common riser, this allows the valve to automatically close when back pressure (from the pipe) rises. The check valve works in the same way.

Photo - coupling

This device has many benefits:

1. Excellent maintainability. This property allows you to repair and replace flanged and lever valve models in case of any breakdowns;
2. Ease of installation and operation;
3. Availability.

The model with a cover is similar to the membrane type, but instead of a diaphragm, a special cover is installed on such a device. It opens only in one direction and even under the influence of pressure from the opposite side, it will not let the flow through. This is due to its special design (the size of the cover exceeds the diameter of the closed hole, as a result of which it cannot move in the opposite direction). Such models are very easy to manufacture, so a simple home-made valve of this design is often used in domestic sewers.

Photo - the principle of operation of the lid model

For an external pressurized sewer system, a flanged check valve is often used. Its installation is carried out exclusively in a static (permanent) way, i.e., in the event of a breakdown, it will be necessary to cut off an entire section of the pipe in order to remove the device and reinstall it in another place. Such a sewer constipation is the most reliable, since it excludes the possibility of leakage or breakage, but at the same time, it is difficult to operate and install. It cannot be simply removed and replaced if necessary and cleaned.

According to the type of installation, the lights are divided into:

1. Horizontal;
2. Vertical.

Accordingly, the horizontal is installed exclusively in the horizontal direction, mainly this design is used on large diameter pipes. Vertical - on communications, where the dimensions of the control pipe do not exceed 50 mm.

In addition, valves with a shutter and a locking mechanism are classified according to the materials from which they are made. It can be HDPE, PVC, steel, cast iron and even copper. The metal valve is often made of a ball type, it tolerates physical impacts well, but the steel locking mechanism fails relatively quickly.

In this regard, a float or polypropylene (PPN) valve is much more profitable. It does not give in to rust, and the locking equipment is more resistant to constant friction. Also, the propylene and plastic valve is of the membrane type.

Installation

Consider how to install a DU-50 ball check valve for domestic sewage with your own hands:

1. The valves are mounted in the main riser. This allows them to control the pressure of the entire system;
2. To do this, it is necessary to cut a certain section of the pipe, into which a locking device is then installed. The hole must correspond to the valve both in diameter and in other geometric parameters;
3. After the device is set to communication. To do this, you will need a design diagram and manufacturer's recommendations for installation. The preferred position of the constipation and its features (membrane direction, type of opening, etc.) must be taken into account;
4. Operation of the device is possible only after 12 hours after installation. This is necessary to solidify the sealant, which lubricates all holes and valve insertion areas.

Photo - installation location

A non-return valve for sewers with a diameter of 110 mm and 50 mm (the most common in apartments and private houses) is able to save the owners of a house or apartment from a lot of trouble associated with blockages and reverse flow of drains. Not expensive and not difficult to install, the device will protect property and prevent unnecessary waste of funds.

The occurrence of sewer backflow can be caused by various reasons, including:

• Misuse sewer system, as a result of which rags, plastic bags and other things block the pipe clearance.
• Appearance during long-term operation sediment on the inner walls of pipes. In this case, not only the clearance decreases, but also a roughness appears on the walls, which contributes to the settling of solid particles and even faster plug formation.
• Incorrect slope of the sewer pipeline. Moreover, both too large and too small a slope contributes to blockages. In order for solid particles not to settle on the inner walls, the water flow that moves them must move at a certain speed. You can change the slope only by completely redoing the system.
• The presence of bends located at right angles, causes the flow of water to change its speed dramatically, while large inclusions can be delayed, forming a plug over time.

Types of check valves

A non-return valve for sewers is a device that allows water to flow in only one direction and prevents reverse flow. Such devices can be installed at pipe joints, in flanges, or cut into the pipeline using threaded connections.

An element blocking the flow of water can be, for example, "plate", fixed inside the housing in such a way that under the pressure of the flow in the right direction it opens easily, and with reverse current it only presses more tightly against the support ring.

Check valve for sewerage - photo of a plastic model

Also common are ball models, operating on a similar principle, but having a ball inside instead of a plate and characterized by greater reliability, ease of maintenance (to maintain efficiency, the device must be periodically cleaned) and maintainability.

The choice between coupling and flange models is made subject to certain rules:

• Flanged Models are suitable for both vertical and horizontal sections of the sewer pipeline, and coupling - only for vertical ones.
• Union valves are optimal for pipes 2.5 inches or less, and flanged ones are suitable for communications with a diameter of 40 to 600 mm. Thus, the most common sizes - a check valve for sewage 50 mm and 110 mm can be in different designs.

Principle of operation and device

Any sewer check valve, vertical or horizontal, blocks the flow of water in the opposite direction. The check valve for pressure sewage has inlet and outlet pipes of different diameters with a chamber between them. Due to the difference in cross-sectional area, different pressures are created in the nozzles, and the ball in the chamber freely passes water. During the reverse stroke, the pressure in the nozzles changes, and the ball presses the membrane blocking the lumen, completely eliminating the ingress of water from the outlet to the inlet.

In other models, the shut-off "plate" in the presence of pressure rises and passes wastewater, and then immediately assumes a vertical position, thereby preventing the possible passage of drains in the opposite direction.

Such devices have a cover fixed with bolts and supplemented with a seal. It is quite easy to open it if necessary to clean the device. Often the check valve in the sewer system is equipped with a shut-off valve.

A plate instead of a ball as a blocking device can be used in large diameter models, such as, for example, a 110 mm sewer check valve, although this condition is not mandatory.

Materials and dimensions of products

The dimensions (mounting diameter) of the check valve for sewage in an apartment depend on the section of the pipeline for which it is intended:

• for toilets choose check valves DN110 mm,
• for the main pipelines of internal systems DN50 mm,
• for external sewage systems - Du150-Du200 mm and more if necessary.

32 mm and 40 mm products are also used.

For the manufacture of non-return sewer valves, the same materials are used as for the production of pipes:

• plastic,
• steel,
• cast iron.

Plastic models are often installed in internal systems from appropriate pipes with a small diameter.

Cast iron pipes and, accordingly, cast iron check valves are recommended for powerful (mainly external) pipelines with a large cross-sectional area, experiencing heavy loads.

Installation of sewer check valves

Do-it-yourself installation of a check valve on a sewer can be done in various ways.

• Models with high capacity can be used for installation on a common sewer pipe. Such options are suitable for private houses, summer cottages and cottages, but not for an apartment in a high-rise building.
• Installing a valve at each drain point in the apartment will prevent an emergency and is especially recommended for residents of the lower (first and second) floors of multi-storey buildings, which are most at risk of flooding when the sewer system is clogged.
• On sewer lines with a reverse slope - in without fail to ensure the normal functioning of the system.

Installation Features

It is best to take care of installing a sewer check valve at the stage. Regardless of the type of device (flanged or coupling), the valve will have to be inserted into the finished system, turning off, draining and disassembling the sewer line. It should also be taken into account that the coupling valve has its own length, therefore, when reassembling the line, it will be necessary to adjust the size of the pipes.

• Optimally, if the diameter of the valve exactly matches the diameter of the pipeline. Otherwise, you will have to use adapters, which unnecessarily complicates the design (the more joining elements, the less reliable the communications section).
• Adapters will also be required if the material of the pipes differs from the material of the check valve, however, it is best to initially select a model that is suitable in all respects without complicating your task.
• A preliminary check of the operability (tightness) of the valve can only be carried out visually. Install the product only if it has no visible defects.

Before you install a check valve on the sewer, you need to know the basic rules that must be observed during installation:

• When choosing a place to install a check valve on an internal or external sewer line, consider the need for easy access to the device for inspection, cleaning and repair.
• The orienting arrow, which is provided with each sewer ball check valve, shows the correct direction of water flow, and therefore should point to the sewer collector. The valve, set the other way around, will not interfere with the drain, but will not perform protective functions.
• All connections must be sealed during installation (for example, with FUM tape).

The appearance of noise and vibration of the check valve indicates a violation of its tightness. To restore the device's performance, there is no need to dismantle the system, it is enough to change the shutter or gasket by opening the valve cover.

If we talk about the cost, then for a 110 mm sewer check valve, the price will be about 2,600 rubles (PVC product), and a 50 mm check valve made of the same material will cost approximately 1,150 rubles. These valves also have the ability to forcibly close the drain and use them outdoors.

Do not confuse the check valve and . It's quite different types equipment.

There are situations when a sewer pump is needed in the kitchen. More about this we.

Non-return valve for sewage photo

Here you can see some photos related to the topic of our article.

We continue the cycle of publications on sewerage systems - the basic principles of their arrangement, the rules for design and installation, the requirements for safe operation, recommendations for regular preventive maintenance. A well-planned and assembled sewage system should not bring a lot of trouble to the owner of a house or apartment. However, the specificity of this engineering system is such that even a minor accident sometimes turns into a real "tragedy".

The topic of today's consideration is a special device in the sewerage system, which is precisely designed to minimize the consequences of some accidents. The device, which, by the way, not everyone knows about, will be useful both for owners country house, and for the owners of apartments, especially those located on the lower floors. This is a non-return valve for sewage: what is it for, how it is arranged and works, what is evaluated when choosing, where and how it is installed.

What is a check valve for?

And this can be very emotionally told by those who, at least once in their lives, have experienced a “fountain” of sewage from the toilet, sometimes flooding not only the bathroom, but also spreading to neighboring rooms. It is perhaps difficult to imagine a more disgusting cataclysm at the household level. Not only do you have to fight a banal flood - the water is saturated with sewage, and you have to overcome all your disgust. And then another - and fight with the remaining "flavors", which, after the most thorough cleaning, still do not go away right away.

And how can this happen? After all, the sewerage system is designed and installed in such a way that water constantly, along the entire length of the laid vertical and horizontal pipe sections, has a free exit by gravity, under the influence of gravitational forces?

Yes, indeed, this should not happen. However, either illiterate pipe laying or violations of the sewerage operation rules lead to this.

For example, there are well-defined recommendations for the slope of pipes, depending on their diameter. But sometimes the "masters" believe that they are smarter than the developers of SNiP, and, perhaps, in order to simplify the wiring, they act in their own way, giving a bias "by eye". But this can already lead to the appearance of sections of the route potentially vulnerable to clogging. Moreover, interestingly, neither a smaller, nor even a steeper slope is allowed - everything should be in accordance with the recommendations.

Sewer pipe slope - what is needed, and why is it so important?

It would seem that what's wrong with increasing the slope - after all, the water will only go faster? It turns out that such “arbitrariness” can then be punished by getting a dense, hard-to-penetrate blockage. What should be - read in a special publication of our portal.

Such consequences can be caused by pipe deflection if a sand cushion was poured poorly, a turn made without using a well, or a difference in the depth of the underground route. There may be other reasons, so to speak, of a "design" property.

But this is more true for owners of houses with an autonomous drainage system. It is somewhat simpler here, since if the drains clearly began to go badly, the owner usually immediately begins to “sound the alarm” and take some urgent radical measures to restore the efficiency of his system. And until now, he forbids his family from loading the sewer.

But truly catastrophic floods are still more characteristic of apartments on the lower floors of city high-rise buildings. Here you already have to sin not on defects in the design of the sewer system, but on the extremely low level of culture (or corny - general intellectual development) of individual residents of the house.

Without thinking at all about the consequences and ignoring the remarks (and sometimes reacting aggressively to them), they stubbornly continue to throw into the sewer pipes (mainly, of course, through the toilet) everything that can pass through it. Including plastic bags, plain paper, rags, large food scraps, potato peels and more.

The reasons for the transformation of toilet bowls into a "mud volcano" is a blockage in the riser or pipe of the subsequent horizontal section.

All these are prerequisites for the formation of traffic jams in the riser (conditionally shown in the diagram as a red ellipse) or in pipes after the riser passes to a horizontal section, for example, in the basement of a high-rise building. As a result, the replenishing drains have an external backwater, they have nowhere to go, and they begin to fill the cavities of the pipes. Outwardly, this may not appear immediately, or it may be noticed by the owners with a delay, that is, the entire riser of apartments on all floors continues to actively use the sewer.

The first open point for the free exit of water (according to the law of communicating vessels) is just the toilet bowl of the apartment located first above the blockage. Here is the flood with sewage!

However, horizontal sections of pipes are more prone to clogging with plugs. Therefore, the first floors are in the main "risk zone". But residents of other floors should not calmly “rest on their laurels” - the practice of master plumbers knows dozens of examples of traffic jams on vertical risers.

Yes, and the owners of houses with autonomous sewerage, in the correctness of the installation of which they have absolutely no doubt, also cannot be calmed down.

It is clear that it is much easier to put things in order among your household by teaching them the rules for operating sewers. But where is the guarantee that the child during the game will not flush some soft toy or something else that can provoke the formation of a cork into the toilet? So a flood can also happen, although, of course, not so large-scale, since a good owner will immediately begin to take adequate measures.

In addition, in a private house there is another potential threat of housing flooding through sewers - during very heavy or long-term rains, during massive snowmelt, during floods, when the collectors can overflow and fail to cope with their function of timely removal of the collected volumes of effluents .

The following conclusion suggests itself: in order to protect your “possessions” from such troubles, you need some kind of device located between the riser and the internal apartment wiring. Such that it freely passes sewage to the outside, towards the drain, but at the same time it reliably closes the passage for any "gifts" from the outside. It is this role (and not only, by the way) that the check valve for sewerage performs.

By the way, sometimes another ability of such a check valve becomes very relevant. There are many cases when sewer pipes become a "tunnel" for the penetration of uninvited guests - rats - into the house. And in the southern latitudes, according to reports, sometimes more “exotic” representatives of the animal world, for example, reptiles, make their way. So - the check valve on the sewer pipe will perfectly protect the house from such an unwanted "visit".

How does a sewer check valve work?

The device of the check valve, as a rule, is simple. Their very name is already clear that it should exclude the possibility of fluid flow in the opposite normal direction. The shutter (flap) in the neutral position is lowered down, and even with a small pressure of the discharged sewage, it will open, giving way to them. But if there is a movement in the opposite direction (caused by an overflow of the pipe further along the route), the damper will immediately block the passage.

Prices for a non-return valve for sewerage

sewer check valve

Differences of valves according to the method of insertion into the system

Valves are installed on sewer pipes of various diameters.

• As a rule, models used at the household level are brought to the standards of plastic sewer pipes with socket connections - from 50 mm and above.

• Starting with a diameter of DN200 and above (as a rule, in private practice, such sewer distributions are not encountered), metal valves with a flange connection are usually used. During their installation, the involvement of specialists is already required, including for performing welding work - for welding flanges at the right points on the route.

• Valves on metal sewer pipes may not be attached directly to the flanges, but installed between two flanges, which are then fitted in a circle with bolts or studs.

Such devices are more compact and easier to install, at least from the standpoint that one set of studs on the flange has to be crimped. But on the other hand, in such valves, there is no way to “squeeze” an inspection window, so if you suspect a malfunction or blockage, you will have to carry out mandatory dismantling.

• In autonomous sewer systems, it is unlikely, but in centralized ones, yes, there can be check valves in a metal case with nozzles designed for installation in sockets of old-style cast-iron sewer pipes.

• Finally, there are check valves that are installed either at the beginning or at the end of the pipe. For example, equipped with their own external cuff, which is put on the outlet pipe (outlet) of the toilet bowl. And then the socket of the sewer pipe is already put on, and the damper is inside it.

Or, conversely, with a socket - for installation at the end of the last pipe along the route. For example, at the entrance to a differential or rotary well, or at the point of discharge from a pipe into a sewer.

Here, to a greater extent, it is just protection not from the reverse flow of sewage (although, in principle, the valve will cope with this task). But, rather, the spring-loaded sash becomes an insurmountable obstacle to the penetration of any unwanted living creatures into the pipe channel, for example, rats. That is, in the absence of fluid flow, the mouth of the pipe will be kept closed.

Differences in the principle of operation of the locking mechanism

Sewer check valves also differ according to the principle of operation of their locking mechanism.

Rotary or reed valve

They are put in first place, if only because, probably, more than 90% of all valves (if not even more) used on sewer pipes on the scale of an apartment or a country private house are of this design.

The device is simple. The shutter is a round flap, hinged in the body of the product. The leaf can be spring-loaded or even closed simply by gravity. In models for horizontal mounting, the movable fastening of this “petal” is located on top.

When the waste masses move, the sash opens slightly under the pressure of the liquid. The larger the volume of drains to be moved, the more the shutter will open. But if the flow goes in the opposite direction (an external support appears), the sash will be pressed against the saddle, to which it is well fitted. That is, the valve will not let the reverse flow of sewage towards the house or, at the local level, towards the plumbing fixture.

The damper itself, unfortunately, is an obstacle to the free passage of large inclusions into wastewater. And if the owners still take liberties in the rules for the operation of the sewer (as described above), the valve itself sometimes becomes a place of blockage. Therefore, it is customary to equip such products with revision windows. These openings can be closed with a cover fixed with screws or latches, a screw plug, etc. In any case, this valve design element allows you to quickly and without any complicated dismantling get to the “problem” place in order to clean it.

Butterfly valves in valves with a diameter of 110 mm or more can be two. This is, firstly, insurance for guaranteed operation of the device, if, say, some kind of interference lingers on the saddle of one of their dampers for a snug fit of the sash. And secondly, the second damper is usually also equipped with a manual control handle. It allows, if necessary, to quickly perform an emergency closing of the valve. In some models, the handle makes it possible to set the maximum opening of the sash - when there is a need to adjust the intensity of the flow of discharged effluents.

However, most kapans with one damper are still equipped with an emergency shut-off handle.

The most sophisticated models can also be equipped with an electric drive that allows you to remotely control the closing of the damper. But the need for this in a not too large-scale home sewer network is debatable. However, it is, of course, the master's business.

Lift Type Locking Mechanism

Rarely seen, but still.

This is a valve assembled in a metal body with connecting flanges, the lower part of which is almost identical to a conventional gate valve. Only instead of the valve itself, a cover is fixed on top. It has a guide channel on the bottom side for moving the stem with a poppet valve. There is a spring that, when at rest, holds the flapper against the seat on the bottom of the valve body.

The force created by the spring is such that the flow of sewage with its pressure should raise the damper without any problems, that is, the passage opens. But if the movement of the liquid starts from the opposite side, the reverse flow will “help the spring”, that is, with its pressure, press the plate tightly against the seat.

I must say that this is not the best solution for sewer wiring, in which drains may contain large inclusions. Due to the complexity of the shape of the channel in the body of such a valve, it can become a potential blockage site. The removable lid, of course, allows for cleaning, but nonetheless. For dirty water with minor impurities-suspensions - it will still work, but for sewage with their "unpredictability" - it's better not to.

Ball Type Check Valve

A very interesting and reliable design is a check valve with a flap in the form of a ball. The movement of this ball in the cavity of the body of the device provides an overlap or opening of the passage for the flow of effluents.

The ball is made of synthetic rubber or aluminum alloy, but again - with a rubber coating. This is important in terms of its good fit to the kapan saddle. In many models, for maximum tightness of the valve in the closed state, its seat is also equipped with an elastic ring gasket.

In the upper part of the case there is a cavity (closed from the outside with a lid). It is in this cavity (compartment) that the ball will roll if a force is applied to it from the side of the fluid flow following in the right direction (indicated by an arrow on the body). To do this, two inclined protrusions-guides are made on the inner walls of the housing.

How it works? Let's look at the diagram:

Everything is very simple. At rest, the ball, under the influence of gravity, rolls down to the saddle. In this regard, such a valve is allowed to be installed only on a horizontal section of the sewer pipeline, with an inspection window (beveled compartment) exclusively upwards. You cannot install it on a vertical sewer riser, since in this case it will work only when the liquid moves from the bottom up, that is, on a pressure pipe, which in our case the sewer is not.

If the flow is in the right direction, then the fluid pressure is sufficient to overcome the ball's gravity vector and roll it higher along the guides, thereby freeing the passage. The greater the flow pressure, the higher the ball will move, which means the more the valve will open.

But if the flow changes direction for some reason, then, firstly, the ball will immediately roll back to the saddle. And secondly, the pressure will also firmly press the ball to the seat, thereby increasing the tightness of the closed position of the valve.

Ball valves are quite convenient and reliable. The wear of the ball, of course, is gradually going on - signs of leakage may appear during the reverse flow of water. However, this part is replaceable, and there is no difficulty in removing the old ball and installing a new one. It is enough to unscrew the revision cover fasteners to gain access to the valve mechanism. After cleaning the cavity, the ball returns to its place (or changes to a new one), the lid is placed and screwed on. And that's it - the valve has regained full performance.

And yet, such devices are not so common in domestic sewer systems, they lose in prevalence to rotary ones. Although, in the personal opinion of the author, not entirely deserved.

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In various sources of information, you can also find references to poppet-type valves, of the type that are widely used on water pipes. Or about double-leaf dampers with two symmetrical 0-blade dampers located on the central axis and opening from the periphery to the center (a very common valve pattern on the air ducts of ventilation systems).

However, it hardly makes sense to speak seriously about the applicability of such devices on sewer mains. Even a cursory glance at the diagrams shown should be enough to understand how serious obstacles such valve mechanisms become for the kind of pollution that is inherent in domestic sewage. That is, in these places, dense blockages will necessarily form very quickly and frighteningly often, requiring the intervention of the owners. And this, mind you - with a perfectly serviceable sewage system and the correct direction of movement of wastewater. Just imagine how convenient such a system would be in operation.

We repeat once again - in autonomous sewerage systems of a private house or in areas of internal home (apartment) wiring of general waste collection systems, simple and fairly reliable rotary valves with a movable leaf hinged on top most often stop. A variant with a ball locking device is possible. All the rest - it is better not to even consider on the indicated scale.

When is a sewer check valve required? Which to choose?

In what cases is it necessary to do without a non-return valve?

It must be said that the check valve is still not considered as a mandatory sewer element for installation. Many systems do well without it. However, in some cases, the installation of such a device, if it is considered not a categorical requirement, then an urgent recommendation - in full.

1. This applies to apartments on the first floors of urban high-rise buildings. By and large, the residents of the second floor will sleep more peacefully if their entrance from the riser is protected by a check valve. The explanation is simple - a zealous owner lives on the first floor, who defended his possessions. That is, the nearest point for the exit of sewage in case of blockage moves higher.

They usually do not install above the second floor, since the high water column created in the riser itself should already “push through” any theoretically possible blockage in the horizontal basement section of the sewer.

Although, "history" knows cases when blockages were formed on common risers above the level of the first - second floors. By the way, check valves that are completely unnecessary in these vertical “main” sections can contribute to this. It should be correctly understood that any valve, even fully open, becomes an unnecessary obstacle to a variety of debris and dirt carried by drains. That is, a potential threat of clogging.

If the owners of apartments above 1 ÷ 2 floors are not sure about the correct installation of the common house system and the accuracy of the operation of the sewer by their neighbors in the riser, then nothing prevents them from installing check valves at the transition points of the apartment interchange to the general network. Yes, these are additional expenses, but sometimes they are justified.

2. Almost the same can be said about owners or tenants of retail, office or other premises in semi-basements, basements, on the first and second floors of residential buildings. It is better to immediately protect your possessions (even if temporary), rather than subsequently pay for repairs, and even against the background of the forced downtime of the enterprise (company).

3. Even a private house connected to a central sewer, or equipped with high-performance and carefully calculated, with sufficient operating margin local treatment facilities, the owners still should not be complacent. Situations are different, sometimes even such that they seem completely unbelievable even in theory. So it is better to supplement your system with check valves to ensure that you are not flooded by sewage.

At the same time, if possible, it is better to take this locking mechanism outside the house - to the outer section of the route, providing for it a separate revision well. Naturally, with such an arrangement, the depth of soil freezing in the region should be taken into account, and thermal insulation issues should be considered in areas of pipe laying that are vulnerable to low temperatures.

Prices for sewer pipes

sewer pipes

Check valve end type, installed at the outlet of the pipe.

As already mentioned, there are also special models of check valves, they are installed not in the gap of the sewer pipe, but at its end. For example, when draining sewage collected in the house into a differential well or collector.

By the way, any of the mentioned types of valves in the sewer system of a private house also becomes a barrier against the penetration of rats and other unwanted animals.

We must add one more nuance. Of course, this is very great luck, if by installing one high-quality valve it is possible to immediately protect all of its internal wiring of the return flow of sewage from the outside. But sometimes this is not possible - for various reasons. And then it is necessary to equip each of the pipes suitable for the riser with its own valve of the corresponding diameter. For example, one large valve on the outlet of the toilet bowl, one 50 mm - on the pipe coming from the side of the bathtub, washbasin, shower cabin. And one more - on the pipe coming from the kitchen.

So, by the way, much more reliable. The theoretically possible negative mutual influence of various plumbing fixtures in the event of a general or some kind of local blockage is excluded. Often in problematic systems, the valve is completely installed on each plumbing fixture. In addition, you can purchase special siphons for sinks and sinks - with a built-in ball or petal check valve. Or special valves for installation on the drain of household appliances connected to the water supply and sewerage (washing machines or dishwashers).

How to choose a return valve?

In the assortment of specialized plumbing stores, there are many models of non-return valves. But basically you can see that many of them are analogues, only slightly differing in individual details.

What criteria should be evaluated when choosing a valve?

• First of all, of course, is the diameter. The vast majority of domestic sewer valves are equipped with a socket connection. And it is designed for installation in pipes with a diameter of 50 or 110 mm (less often - 160 mm).

The valve is designed for installation in a pipe of a specific diameter only. That is, installation using some kind of adapters to switch to a different diameter is not welcome.

• Valve material. For the most part, plastic models are presented (polypropylene, ABS, PVC). And since in modern construction plastic sewer pipes also prevail, then the choice is obvious.

If old cast-iron pipes are still preserved in the house (apartment), and there is no desire or opportunity to change them, then you can also purchase the corresponding model for them. Although, most plumbers will still prefer to either replace the old wiring, or embed a polymer valve into cast iron - there are special transition cuffs for sale for this.

Quality valve dampers are often made of stainless steel.

• By the way, many quick-witted readers probably already understood that manufacturers tried to keep the color marking of products similar to those used on pipes. That is, gray is exclusively for wiring located inside the building, orange is universal, which can also be mounted on external sewer networks. The material for the manufacture of "red" devices has increased strength, resistance to temperature extremes, etc. Quite often, the permissible operating conditions are indicated in the technical documentation of the product.
• The functionality of the device is necessarily evaluated. The parameters of the valve should specify whether it is designed only for the passage of water, or whether it can also cope with fecal effluents. This is very important, since some models are similar, you can make a mistake, and soon get an inoperable system.
• It is necessary to evaluate the dimensions of the device - compare them with the place where it is planned to be installed.
• Most often, they try to place valves on horizontal sections of sewer pipes. However, lack of space or other circumstances may force you to resort to vertical installation. This means that the valve must be designed specifically for vertical installation - not all models support such a spatial orientation.

• In the valve passport, you can find the value of the maximum allowable backflow pressure, for example, from 0 to 5 meters of water column. That is, if this parameter is exceeded, the manufacturer does not guarantee that the damper will not be deformed or torn off. But, to be honest, to imagine a pressure equivalent to a five-meter column of water from the side of a collector, septic tank or well (considering that there is a priori no equipment capable of creating forced pressure) - no imagination will be enough.

So you can reassure yourself that all quality domestic sewer valves are designed for any theoretically possible back pressure.

• When purchasing a valve, it is best to opt for models equipped with the possibility of forced closing of the valve. There are situations when you have to urgently resort to this function. But, in principle, most models are equipped with it, as they say, “by default”.

• Models of both domestic and foreign manufacturers are on sale. By the way, the case when there is no obvious predominance of the quality of imported products. Here, soon, it is better to proceed from those considerations, whether the manufacturer gives a guarantee to his products, and if so, what kind. And do not forget to draw up warranty documents when buying.

Well, if the product is not accompanied by any documentation at all, it makes sense to think whether it is worth contacting such a “gift”, despite the very attractive cost, and whether it will fail in a critical situation.

Brief overview of non-return valve models for sewerage

Naturally, since we are talking about domestic sewage, we will limit ourselves to models with diameters of 50 and 110 mm.

Illustration	Brief description of the model	approximate cost
	"Capricorn" 50 mm, production - Poland. For internal wiring only. Drainage without faeces. Polypropylene. Manual shutter - provided.	950 rub.
	Check valves for individual plumbing fixtures. Production - McAlpine(Scotland). Diameters - from 32 to 50 mm. Threaded coupling with conical gaskets. Material - PVC. Horizontal and vertical installation is allowed. Drainage without faeces.	Depending on the diameter - from 500 to 900 rubles.
	Check valve for pipe 50 mm TP-86.50, domestic production. For internal wiring, drains without faeces. Polypropylene. Only horizontal installation. Return flow pressure - up to 3 meters of water column. Operating temperatures - from +1 to +35 ℃. The declared service life is up to 50 years. Manufacturer's warranty - 12 months.	450 rub.
	check valve TP-85.100, also domestic production. Diameter - 110 mm. For external and internal wiring on horizontal pipe sections. Including - and for pipes with fecal effluents. The remaining characteristics are similar to those of the TP-86.50 valve.	1000 rub.
	Check valve F110 PESTAN(production Serbia). ABS plastic + polypropylene. Stainless steel shutter. Diameter - 110 mm. For external and internal wiring, horizontal position only. Working with faecal effluents. Manufacturer's warranty - 15 years!	1450 rub.
	Check valve for sewer pipe 110 mm Ostendorf 908002. Any type of drains, indoor and outdoor installation, horizontal orientation only. Polypropylene. The maximum back pressure is 5 meters of water column. Maximum temperature: +95℃. Manufacturer's warranty - 1 year.	1720 rub.

The list includes popular models good quality with moderate prices. There are, of course, valves and more "tricked out", with several gate valves, with sensors and remote control of dampers. The cost of such models, of course, can be many times higher. But the need for such devices does not always arise and not for everyone. So dwelling on them does not seem to make much sense.

Installing a check valve on a sewer pipe

The installation of such devices, if there is already complete clarity where they will be mounted, is not particularly difficult. And especially in those cases when the valve is installed during the installation of the entire sewer wiring, for example, during construction or major repairs.

Everyone who already has experience in assembling sewer pipes in his practice should cope with this task. Another thing is if everything has to be learned on the go. In such a situation, it is better not to train on the valve - start with something simpler. That is, it would be wiser to invite a specialist.

Almost all valves are equipped with a flare at the inlet and a straight pipe at the outlet for the familiar flare connection. That is, this should not be a problem under normal installation conditions. The task becomes more complicated if the valve has to be cut into an already laid pipe section. And at the same time, it is impossible to temporarily shift some edge in some way. For example, the toilet is walled in, the riser is also motionless, and the socket connection still requires a certain freedom of translational movement of the joined parts.

There is a way out - using either a compensating pipe, with an elongated socket section, or a coupling equipped with cuffs on both sides.

Such branch pipes and couplings are available for both 50 mm and 110 mm pipes.

The sequence of actions is as follows:

• A pipe section is cut out at the site of the planned installation. In such a way as to free the socket for the installation of a straight section of the valve pipe. And on the other hand - to put on the compensation pipe by its subsequent insertion into the valve socket.
• The cut section is removed from the socket of the pipe going further along the route - it will no longer be needed. The remaining cut edge is carefully cleaned of burrs, a neat chamfer is removed along the end.

• The connection areas can be lubricated with silicone grease to reduce friction during installation. If not, then a thick soapy solution will do.
• A compensation pipe is put on the cut edge of the pipe and sinks to the full depth of its elongated socket.
• The valve is inserted in a straight section into the socket remaining on one side of the section prepared for installation. It sinks to the end of the bell.
• Then the compensating pipe is moved back so that its straight section completely enters the valve socket.
• Since with such an installation, the parts remain a certain degree of freedom, and the forces during backwater are still considerable, so that no displacement occurs during operation, it would be better to tighten the connecting nodes with metal clamps.

If there is no socket in the section of the pipe where the valve is required, then a coupling is used. After trimming and cleaning the edges, she puts on the edge that is closer to the exit, and moves, opening up a place for a joint. After that, the valve is put on with its socket on the opposite end of the cut pipe with a drawdown until it stops. Then the valve is aligned coaxially with the route, and the previously put on coupling is shifted onto its straight part, which will completely block the joint. Here, too, it is advisable not to be too lazy to strengthen the knot with metal clamps.

• The place of installation of the device should be chosen in such a way that access is provided for regular maintenance. Any valve is an extra hydraulic obstacle where blockages can form. No wonder there are covers for quick access if you need quick cleaning. By the way, a clogged valve with a poorly fitting damper may not be saved in the event of a reverse flow of sewage!

• It never hurts to check for leaks before installing the valve - how it holds back the flow of water. It is easy to check this by simply pouring water into the valve from the outlet side - the operation should occur.
• Just before installation, make sure that the arrow showing the direction of water flow is correctly positioned.

• Do not forget to assemble the check valve itself before installation and start-up. Many models are sold unassembled - they are accompanied by the manufacturer's assembly instructions. Usually the assembly itself is not difficult. The main thing is not to forget about it. There are cases when an inexperienced installer got a problem simply because of a loosely screwed inspection cover or an incorrectly installed damper.

Well, for the rest, it remains to periodically monitor the condition of the valve, carry out cleaning if necessary, check the tightness of the damper to the seat. By the way, for some models, you can purchase sensors that will signal the owners about a problem that requires their intervention.

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At the end of the publication - watch the video, in which, perhaps, the remaining incomprehensible points will be clarified.

Video: Sewer check valve - purpose and principle of the device