How does a sewer check valve work?

Sewer non-return valve featuring two rotating flaps. Additionally, one of them has a manual damper control lever installed.

Usually, the check valve device is straightforward. It should be obvious from their name that they rule out the possibility of fluid flowing in a direction other than the usual direction. When the shutter (damper) is lowered to its neutral position, it will open and give way to them even in the presence of a small amount of sewage discharge pressure. However, the valve will instantly close the passage if there is movement in the other direction (due to overflowing the pipe further along the route).

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

Diverse diameter sewer pipes have valves installed on them.

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

• Starting from the diameter DN200 and higher (as a rule, in private practice, there is no need to face such sewer wiring), metal valves with flange connecting are usually used. During their installation, the involvement of specialists is already required, including for welding work – for welding flanges at the right points of the highway.

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

These devices are easier to install and more compact, at least when viewed from the angles where only one set of studs needs to be squeezed onto the flange. However, since there is no way to "squeeze" the audit window in such valves, mandatory disassembly must be done in the event that issues or blockages are suspected.

• In autonomous sewer systems, it is unlikely, in centralized, yes, the check valves in a metal case with pipes designed to install cast -iron sewer pipes of the old -sized can be found in a metal case.

• 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. And then the bell of the sewer pipe is put on, and the damper is inside it.

Alternatively, with a socket, which would be installed at the terminus of the final pipe in the path. For instance, at the point where a pipe empties into a sewer or at the opening to a differential or rotary well.

This time, it’s more than just preventing sewage from backing up—though, in theory, the valve can handle that too. Instead, any unwanted living things—like rats, for example—are unable to pass through the spring-loaded flap and enter the pipe channel. That is, the pipe’s mouth will remain closed when there is no liquid flow.

Differences in the operating principle of the locking mechanism

The way that sewage check valves lock is another way that they vary from one another.

Rotary or reed valve

If for no other reason than the fact that this type of valve is likely found in over 90% of all valves used on sewage pipes in private country homes or apartments, they are ranked #1.

The apparatus is basic. The shutter is a circular flap that is hinged within the product’s body. The sash may close automatically by gravity or with the help of a spring. The movable mount of this "petal" is on top in models intended for horizontal installation.

The sash slightly opens due to the liquid’s pressure when the waste material moves. The shutter opens to a greater extent with increasing waste volume moved. In the event that the flow is directed in the other direction, resulting in the appearance of external support, the sash will press against the saddle, to which it is properly fitted. In other words, the valve will prevent sewage from returning to the house or, locally, to the plumbing fixture.

Regrettably, the damper itself prevents large inclusions in wastewater from passing freely. Furthermore, if the owners continue to deviate from the sewage system’s operating guidelines (as previously mentioned), the valve itself may occasionally become clogged. As a result, audit windows are standard on these products. These holes can be sealed with a threaded plug, a lid fastened with screws or latches, etc. In any event, this valve design feature makes it possible to reach a "problematic" cleaning location swiftly and easily, all without the need for intricate disassembly.

In valves with a diameter of 110 mm or greater, there may be two rotary shutters. First and foremost, this serves as insurance for the device’s assured functionality—that is, if we were to describe it as a barrier to a tight fit of the leaf on the saddle of one of their flashes. Furthermore, a manual control handle is typically attached to the second damper. If necessary, it enables you to quickly shut down the valve in an emergency. When adjusting the intensity of the discharged effluent flow, the handle on certain models allows the sash to be opened to its maximum value.

Nonetheless, an emergency shut-off handle is still present on the majority of valves with a single damper.

The most advanced versions may additionally come with an electric drive that lets you operate the damper’s closure from a distance. However, there is debate over whether this is necessary in a home sewer network that isn’t too big. Of course, though, that is the owner’s business.

Lift type locking mechanism

Not typical, but nonetheless.

The lower portion of this valve, which is assembled in a metal body with connecting flanges, resembles a traditional gate valve nearly exactly. Only, there is a cap fastened to the top in place of the valve itself. A guide channel for guiding the rod with the poppet valve is located on the bottom side. When the flapper is at rest, a spring presses it up against the seat at the base of the valve body.

The spring’s force is such that the pressure from the sewage flow should lift the damper without any issues, allowing the passage to open. However, if the liquid moves in the opposite direction, the reverse flow will "help the spring," or press the plate firmly against the seat with its pressure.

It must be acknowledged that, particularly for sewer lines, where the drains may have significant inclusions, this is not the most effective solution. Owing to the intricate design of the channel within the valve’s body, it may potentially become a point of obstruction. Of course, the detachable lid makes cleaning possible, but still. It will still function for contaminated water with tiny suspended particles, but it is best to avoid using it on sewage due to its "unpredictability."

Ball Type Check Valve

A check valve with a ball-shaped damper is an extremely intriguing and dependable design. This ball’s movement within the device body’s cavity makes sure that the waste flow channel is either blocked or opened.

The ball is composed of aluminum alloy or synthetic rubber that has been coated in rubber once more. This is crucial for ensuring that the capan seat fits properly. A ring gasket made of elastic is also installed on the seat of many models to ensure the valve is as tight as possible when closed.

The upper portion of the case has a cavity that is covered with a lid when closed from the outside. If a force is applied to the ball from the side of a fluid flow traveling in the correct direction (shown by an arrow on the body), it will roll into this cavity, or compartment. Two angled protrusions—guides—are built into the inner walls of the housing for this reason.

How does it operate? Now let’s examine the diagram:

Everything is really easy to understand. When everything is calm, gravity pulls the ball down to the saddle. Accordingly, only a horizontal section of the sewer pipeline may have this type of valve installed, and it must have the inspection window (sloping compartment) facing upward. Installing it on a vertical sewer riser is not possible because it will only function on pressure pipes, which are not sewers in this situation, where liquid moves from bottom to top.

The ball will roll higher along the guides and overcome its gravitational vector if the flow is directed in the correct direction, opening the passage. The ball will move higher and the valve will open more when the flow pressure increases.

However, in the event that the flow changes direction for any reason, the ball will instantly roll back to the saddle. Furthermore, the pressure will force the ball firmly against the seat, tightening the valve’s closed position even more.

Ball valves are incredibly dependable and convenient. Naturally, the ball is gradually wearing down; when the water flows back, leaks may become visible. Nevertheless, this component is replaceable, and it is simple to take out the old ball and put in a new one. All that is required to access the valve mechanism is to unscrew the inspection cover’s fasteners. The cavity is cleaned, the ball is put back in (or replaced with a new one), and then the lid is put on and tightened. That’s it; the valve is now fully operational again.

Nevertheless, these devices are less frequent than rotary in residential sewage systems. However, the author feels that it is not totally justified.

It is more common to come across references to poppet-type valves—akin to the valves commonly found on water pipes—in a variety of information sources. Alternatively, consider double-leaf ones, which have two symmetrical 0-petal dampers on the central axis that open from the periphery to the center (this type of valve is frequently found on ventilation system air ducts).

Still, it defies logic to discuss the usefulness of these devices in relation to sewer lines. It should be evident from even a cursory glance at the diagrams how serious a hindrance such valve mechanisms become for those contaminants typical of home sewage drains. That is to say, dense obstructions will undoubtedly form in these areas very quickly and horrifyingly frequently, necessitating the owners’ intervention. Remember that this is all assuming that the wastewater is moving in the right direction and that the sewage system is fully functional. Just consider how simple it would be to operate such a system.

It’s critical to comprehend the straightforward but vital function of a sewer check valve in preventing sewage backups when learning how it operates. This valve functions similarly to a wastewater one-way door in that it lets sewage flow out but closes tightly to keep it from returning. It detects flow direction via a float mechanism or a flap. The valve quickly closes to keep sewage in the pipes and prevent flooding of your home or property when it tries to reverse its course because of blockages or flooding. This simple but efficient technology guards against water damage to buildings during heavy rains or sewage system overloads while also aiding in the maintenance of sanitation.

We will reiterate: simple and fairly dependable rotary valves with a movable sash articulated on top are typically used in autonomous sewage systems of private homes or in areas of internal home (apartment) wiring of common systems for collecting drains. equipped with a ball locking mechanism. It is preferable to ignore everything else on the provided scale.

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