What is a non-return valve for?

The arrangement of the water supply and heating system is a very responsible and important occupation that needs a professional approach. This is due to the need for the correct configuration and selection of all necessary components. In this article we will tell you why you need a check valve and what you should pay special close attention to when choosing and installing it.

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What is a check valve?

The non-return valve is a type of pipe fittings that performs a protective function and prevents the movement of the working medium in the opposite direction of the main flow. These locking devices have a fairly simple and understandable design, which greatly simplifies the procedure for their operation and installation.

Most residents of apartment buildings and private houses wonder, why do we need a check valve in the water supply? In fact, it is this type of protective armature that not only ensures the correct functioning of the water supply system, but also allows significant savings.

Important! The main saving factor is that the water is retained in the system, and does not go back.

What is a non-return valve for?

This device is suitable for installation on any type of communications:

1. It is mandatory to install a check valve in systems where water is taken from a well or a well. The main objective of this device is to maintain pressure in the system, which in turn prevents the leakage of water, even in the event of problems with the power supply.
2. Also, due to the presence of a non-return valve, the life of the pumping equipment is significantly extended, because it never functions “dry”.

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Types of Check Valves

Between themselves, check valves differ not only in design, but also in the way they are connected to a common pipeline system. The type of mount may be as follows:

• One-piece connection - welding or soldering, which can be performed on the pipeline from any material. This method of attachment is quite labor intensive, but when properly performed it provides excellent tightness.
• Flange mount - two elements that resemble a disk in shape, are pulled together by means of special bolts. This connection option is often used in large pipelines.
• Coupling connection - best suited for small-volume piping systems and is a fastener assembly with internal thread. Most often, this method is used in private buildings.
• Wafer mount - designed for products that have a flat shape and are performed by fixing them between two flanges.

Important! The most suitable mounting method should be chosen after consulting with a specialist in advance, since it is the characteristics of the installation work that will depend on this characteristic.

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Application area

There are water supply systems where the use of a non-return valve is mandatory, as well as pipelines in which the use of this valve is recommended by specialists. This equipment has found its application both in the industrial sector and utilities, as well as in residential premises.

To understand better why a check valve is needed, you need to know in which domestic situations it is used. These are mainly such directions:

• when equipping risers for supplying cold and hot water in apartment buildings;
• during operation of storage systems for heating water - boilers, electric and gas columns;
• to equip an autonomous heating system in a private house;
• when using deep pumps for water supply from wells.
  

Central water supply systems in apartment buildings

Often in each apartment hot and cold water is supplied, which is carried out through the use of separate risers. Basically, the pressure in different systems is different and sometimes this difference can be very significant.

When using water, we usually open both mixers at the same time, which allows us to obtain a water flow of the desired temperature. As a result of this action, water moves in the direction from a higher pressure level to a lower one.

That is why there are situations when a riser with high pressure overpowers a weaker line, and as a result of such interaction, backward movement of water through the pipe can be observed.

Important! If the water supply system is improperly equipped, a situation may occur when a hot stream appears in the riser designed for cold water.

This situation can be avoided by using a non-return valve, which is installed immediately after the water consumption meter. In these cases, the installation of fittings is mandatory and documented among the basic requirements of water supply organizations.

Installation of storage heaters

If you decide to install a boiler or a column in your apartment, then experts will definitely advise you to install a non-return valve in the area of ​​cold water inlet into the system. This recommendation is associated mainly with the peculiarity of the heater.

Such a device is usually filled due to the pressure of cold water, and during operation, due to the natural processes of physics, when the liquid is heated, its pressure level rises. Thus, hot water tends to begin the reverse movement along the line with cold liquid. For such an example, we hope you understand better why a check valve is needed, because it is it that prevents this phenomenon.

Organization of autonomous heating in the house

The use of check valves is necessary if you are installing an autonomous heating system for heating a private living room. This need is associated with the use of several working circuits, which can have different temperature of the working environment and different functional purpose.

For example, the following systems are often equipped:

• circuit for heating water in a storage device - a boiler;
• circuit for supplying water to heating radiators;
• circuit for the implementation of underfloor heating.

Each of the above systems has its own hydraulic resistance, which is regulated by a circulation pump with a variety of pressure characteristics.

With such an autonomous heating system, users often encounter a situation where pumping equipment with more power can provoke a reverse movement of the work flow through a system with less powerful pumping equipment. The occurrence of such a situation is not only undesirable, but also unacceptable. Therefore, experts insist on the mandatory installation of check valves at the outlet of each circulation pump.

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Design features

Between themselves, the valves differ not only in the destination and method of attachment, but also in the structural structure. Most often, for the equipment of water supply systems, the following types of check valves are used.

Interflange

The main advantage of this type of fittings is the democratic price and small dimensions. The most rational use of such structures for systems where there is a significant lack of space. Installation of this equipment is quite simple, because it is enough to squeeze between the main structural elements. The main condition is to install the check valve in the correct position so that the water flow freely flows in the right direction.

The main working unit of this design is represented by a clamping disk, which is fixed by a spring of a certain stiffness. Under the pressure of the flow, the valve opens, and when the physical effect weakens, it automatically closes, which prevents the movement of the working medium in the opposite direction.

Important! For water supply systems, where there is a danger of water hammer, it is customary to use bivalve mechanisms with the help of which a high level of protection is achieved. This kind of system is presented in the form of two circles, which are fixed on a common axis. On many mechanisms of this kind, the presence of shock absorbing nodes, which soften the blows, is provided.

Petal

The working unit of such a non-return valve is presented in the form of a special slide valve, which has an axis located above the passage opening. Under pressure of the water pressure, the collapsing element is lifted and the system is filled.

Important! When choosing this model of a non-return valve, it should be borne in mind that the slamming of the main element with a decrease in the pressure of the working medium causes significant wear of the equipment. Therefore, it is better to give preference to equipment with a shock-absorbing system.

The main advantage of such check valves is the possibility of their operation in the construction of pipelines with a large diameter.

Lifting

Lift check valves consist of a slide valve that moves up and down. When the pressure of the working medium decreases, this system lowers into the saddle area and completely shuts off the water supply system. A node of this type is mounted on the horizontal region of the pipeline so that its axis is strictly vertical.

Important! The main advantage of this system is the ability to replace certain parts without replacing the entire assembly.

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Stock footage

In this article, we talked about why we need a check valve in the water supply system, how it can be and how it is used. We sincerely hope that this information will help you make your plumbing system as efficient and safe as possible.