Ball gas valve for underground installation: selection criteria + operating rules

Timely isolation of the gas pipeline section on which the accident occurred is necessary for the prompt elimination of the problem. In such situations, one cannot hesitate. Do you agree? Using a gas ball valve for underground installation, you can quickly and flawlessly shut off the medium transported through the gas pipeline.

Correct installation and proper use of the ball valve will help increase its life and ensure the quality and safe operation of the gas supply system. We will tell you everything about the design of this type of valves. Let's analyze what the principle of its operation is based on.

Features and purpose of ball valves

The oil, chemical or gas industry cannot be imagined without valves. The shut-off pipeline fittings produced on modern high-tech equipment will ensure the safety of the entire system.

Locking gas pipeline fittings - This is a required design element. These devices are used for both external gas pipelines and internal systems.

The purpose of gas ball valves is quite large:

• equipping complex systems through which aggressive and non-aggressive environments pass;
• use in pipelines located in hard-to-reach places;
• efficient operation in case of nominal pressure up to 16 MPa, etc.

When using gas ball valves, there is no need to create a manhole and enclosing structure.

If you need to dismantle any product, part of the pipes is simply cut off. In this case, the valve must be in the open position so as not to damage the shut-off ball. The design of the valve is not intended to regulate the flow of the pumped medium.

If it is required to install a restricting device on buried highways, then most often they use ball gas valves driven by an electric motor, reducer or pneumatic cylinders. If the design contains hydraulic or pneumatic actuators, they can be controlled by external sources or the conveyed medium.

For this, holes are made in the body of the gas valve through which the drive is piped. To prevent the structure from breaking, the spindle extension is protected by a shell in the form of a vertical tube.

Moreover, this tube is attached to the upper part of the valve body in a flanged manner. Most often, stopcocks are installed directly where the gas equipment is located.

At the same time, for each source of gas consumption, an individual valve is mounted, which ensures the sealing of a particular pipe. It is also possible to install one additional valve with a ball valve at the inlet, which is responsible for completely stopping the gas supply. Such an installation meets all the necessary security requirements.

Gas ball valves provide two-way gas movement in the pipeline. Such devices can be mounted on gas pipes any diameter. They can be used on trunk networks, used in the operation of storage facilities and in the transportation of natural gas over long distances, etc.

Pros of using a gas ball valve

A ball valve designed for underground installation is a device that is necessary to shut off the gas flow in pressure pipelines laid in trenches.

These devices are used in both industrial and domestic environments. Gas valves provide fast and complete shut-off of the flow of the working medium. Their widespread use is due to their reliability, durability, strength and relatively low cost.

Ball valves are made of heavy-duty materials, resistant to corrosion, inert to aggressive media. In production, alloys are used that tolerate all kinds of mechanical damage without problems and deformations.

Products have high wear resistance regardless of operating conditions. Ball gas valves are able to maintain their technological properties for a thousand (or more) cycles without any malfunctions.

In this case, the temperature of the moving and the environment can be practically any. It has been experimentally found that gas ball valves are capable of withstanding temperatures from -60 to +80 degrees. Most gas taps will last much longer than the manufacturer claims.

The closure of the gas ball valve is made in a spherical shape and has an opening through which gas passes through the pipes. The hole diameter is selected in accordance with the dimensions of the pipeline. Adjustment of the throughput of the line is provided due to the possibility of rotation around its axis of the locking mechanism.

In the working position, the lock is located perpendicular to the pipeline, and it can be easily closed by hand by turning the handle slightly. When rotated 90 degrees, the through hole side changes to a solid surface.

With a smaller turn, the pipe will be partially closed. But manufacturers do not recommend leaving the structure in a half-open state, because this contributes to increased abrasive wear of the device.

In intermediate positions, the O-rings can be completely damaged or partially deformed due to too high a flow velocity of the pumped medium. This in the future can lead to serious damage to the crane, its repair or replacement.

The body of the product is highly airtight. The use of metals and special alloys in the structure helps to reduce the weight of the structure. Such shut-off valves for gas pipelines can be easily installed in hard-to-reach places.

The use of quality gas ball valves is beneficial from an economic point of view. These devices have a huge margin of safety and can function fully without needing to be replaced for many years.

This is especially true for ball valves from well-known and trusted manufacturers. At the same time, you can make sure of the quality of any crane by checking the certificates of conformity, which confirm the quality of the products.

Typical design of a gas ball valve

Ball valves for underground installation of different brands have approximately the same structure. The design of products is due to their performance and purpose.

A standard gas valve for installation on underground lines consists of:

• a sealed body, most often made of brass or steel;
• a shut-off ball, which further blocks the gas supply (because of this element, the valve is called ball);
• saddle, which is responsible for ensuring that the shut-off ball does not move anywhere;
• a piece of connection pipe with a special thread, which is then welded to the pipeline;
• the throat part required to pass the stem;
• extended connecting rod;
• washers contraindications;
• parts responsible for the tightness of the structure (O-ring, spring, ring and flange, made of soft and durable materials, for example, ethylpropylene rubber);
• a handle made of strong material with a PVC coating, thanks to which the entire product is controlled, and a nut that fixes it;
• stopper or handle travel stop.

In the production of component parts, alloy and stainless steel is used, which has high anti-corrosion performance. Elastic fluoroplastic is used to seal the parts. Thanks to this polymer, the structure becomes water resistant.

Fluoroplastic ensures the tightness of the coupling, smooth screwing in and easy dismantling. This material is highly resistant to all kinds of aggressive media, and its surplus is calmly squeezed out when the thread is tightened.

Due to the peculiarities of the structure, the closed position of the valve ensures complete sealing of the pipeline. The crane itself is small in size, which greatly simplifies its installation. During installation, both welded and threaded connections are permissible.

In this case, the thread at the end of the pipe should not be longer than the valve thread, because otherwise after screed threaded connection, the end of the pipe will abut against the O-rings, leading to premature damage to the crane.

The gas ball valve can be installed together with the pipe in any position, which in the future can guarantee maximum ease of use and quick access to the problem area.

Crane body for underground installation

The valve body is most often made of alloy steel, carbon steel, stainless steel or brass. Brass products are more expensive than steel taps. But at the same time, both brass and steel do not corrode, due to which the service life of devices made from them increases several times.

Brass and alloy steel have a high level of ductility. However, they are not able to withstand strong and prolonged mechanical stress. For this reason, it is recommended to protect the locking mechanism from impact and friction.

The very design of the gas valve body depends on the following factors:

• method of production;
• internal developments of a specific design bureau;
• the nature of the standards used (TU, GOST, OST or any European directives).

An all-metal non-separable body is considered the most durable, capable of holding any load. First, it is turned on a machine, cast into the formwork by centrifugal force and then welded using additional parts.

Also, the valve body can consist of two vertical halves or three elements. A 2-3-piece split casing is more convenient for maintenance and can be reused after dismantling, but it is less sealed.

Also, the bodies of ball valves are divided into full bore and reduction. In the first case, the diameters of the valve and the pipeline completely coincide, due to which the minimum hydraulic resistance is ensured. In the second case, the pipes are reduced by one standard size, so that the flow of labor can be controlled.

Regardless of the material from which the body of the gas ball valve is made, it must be covered with special protective equipment against aggressive media. For these purposes, various chemicals are used.

Firstly, they include acrylic paint, which is distinguished by its electrical insulating properties. It protects products from induced and stray currents. Secondly, in order to provide the crane with anti-corrosion properties, it is coated with polymer paints and varnishes.

Third, the ball body can be coated with epoxy-based coal paint. This paint is distinguished by high anti-corrosion resistance and resistance to various mechanical damage. Fourthly, a polyurethane foam coating is used to protect the fittings when they are installed without wells directly into the ground.

Ball valve locking mechanism

When choosing a ball valve, special attention should be paid to its locking element - a ball or sphere. The ball should be smooth and shiny. Most often the sphere is made of brass and coated with expensive nickel and chrome plating.

It is quite easy to check the quality of the sealing sphere. To do this, you can check it with a magnet. If the magnet is attracted to the sphere, this indicates that it is made of steel, which is intended for electrical use.

The steel ball of an underground gas valve quickly rusts and cannot be operated for a long time in a humid environment. In this case, the brass ball will not be attracted to the magnet.

Gas cock handle

The ease of use depends on the shape of the handle or handle of the ball valve. Most often, products with a butterfly-shaped handle (butterfly) or a lever are on sale. The lever is more functional, therefore, if possible, you should buy a gas valve with just such a handle.

The lever handle is especially convenient if the valve has not been used for a long time and requires force to turn it. Gas valves always come with green handles. It is not recommended to repaint them.

Varieties of ball gas valves

Modern gas pipelines use gas taps the three most common types, classified by the type of connection to pipes. These are threaded, flanged and welded. Threaded or socket gas valves have a small diameter. Most often they are installed on gas pipelines for commercial premises, private houses and similar objects.

The connection to the gas pipeline is carried out by means of a thread. The threaded connection of the gas ball valve and the pipe must not be overtightened. this may cause damage to the casing of the product.

Flanged valves are connected to pipelines in a flanged manner using bolts. Both threaded and flanged products are collapsible. Those. they can be dismantled, moved to another location and put back at another point in the pipeline.

Welded valves are connected to gas pipelines by welding. Those. they cannot be disconnected from the pipes without damaging the structure. The diameter of the welded fittings varies from 10 to 70 mm. Welded gas valves are tight and reliable. They do not require regular maintenance, which makes them very popular.

General operating rules

The basic rules for operating a gas valve are quite simple and predictable. The valve closes by turning the handle 90 degrees clockwise, and opens by turning it also 90 degrees, but already counterclockwise. If the handle is perpendicular to the axis of the valve, this indicates that it is closed. The parallel position of the handle means that the valve is open.

The working medium passing through this valve must not contain excessively rigid elements and solid impurities that can damage the polished surface of the valve ball. If solids can still enter the ball valve, a strainer should be installed in front of the ball valve.

The ball valve itself must be periodically opened and closed so that it can be easily turned in any direction in the future.

The ball valve should be operated with a standard handle. It is not necessary to use special levers for these purposes, which are capable of lengthening this handle. Opening and closing the valve must be done as slowly as possible to avoid water hammer.

The pressure and temperature at the installation site of the ball valve must not exceed the operating pressure. Ball valves with the same temperature and pressure rating are not allowed for most designs.

The ball valve requires periodic cleaning from rust and dust, as well as tightening the thread. In accordance with the recommendations of the manufacturers, this should be done every six months.

When installing pipelines, a pipe fastening structure is provided that excludes the possibility of external mechanical impact on the crane, taking into account axial, radial or torsional loads.

Repair and maintenance of the ball valve under pressure is prohibited. For full operation, the required section of the pipeline must be pre-cleaned. When cleaning the system, the ball valves must be opened and closed several times.

How to identify a fake?

Before installing the gas valve, it is necessary to check its compliance documentation for the specified pipeline and make sure that the device is not a fake. Counterfeit gas fittings are quite common in the market. When buying a gas ball valve, you should be careful to distinguish an original product from a fake one. To do this, you can use some tips.

To deceive buyers, sellers can forge the accompanying documentation (certificates, declaration, product passport). Branded gas taps are somewhat more expensive, so this kind of deception is widespread in the market.

Also, the following signs indicate a fake:

1. The uneven surface of the crane, on which microcracks and gaps are visible.
2. Clouding of the ball gap.
3. Use of silumin or zinc as a body material.

But it is extremely difficult to determine by eye the exact composition of the material used. For this, numerous chemical analyzes are carried out. They cannot be done outside the laboratory in a limited time frame.

Therefore, when buying a ball valve, you should ask for a product quality certificate, hygiene certificate or declaration of conformity. In Russia, gas ball valves must comply with the requirements of GOST R 9544-2005 and GOST 21345-2005, 28343-89, 23941-2002. Also, certificates may contain references to other regulations and quality standards.

Conclusions and useful video on the topic

The features of choosing a ball gas valve for underground work are described in the video, which is posted below:

Any gas pipeline must be equipped with a reliable shut-off mechanism, especially if the pipes are laid below the surface of the day. The shutter is needed during an accident to isolate certain sections of the pipeline and to carry out repairs on the line in case of partial breakdowns. It will protect against threatening situations and catastrophic consequences.

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