Shut-off and control valves. Pipe fittings. Types of pipeline fittings. Valves for water supply as a tool for managing water supply

In order to find out which type of reinforcement is better to choose, you need to know its main advantages and the principle of operation. The cost and design dimensions depend on the diameter of the pipes, the purpose and the material from which the valve is made.

Gate valves of any type consist of a body and a cover, which form a space ( working area), which houses the shutter. There are two ends on the body, with which the part is connected to the pipeline. These elements can be coupling, threaded, as well as for welding. The body structure contains protrusions called saddles. When the valve is closed, the sealing parts of the valve are pressed against the seats, preventing the liquid from overcoming the working area.

The element that contributes to the movement of the shutter is called the spindle. The mechanism for moving the spindle along the threaded nut is:

• manual
• automated (with the help of an electric drive).

For pipes of large diameters, valves exclusively with an electric motor are used. This provides additional reliability of the locking system.

Types of valves for water pipes

Wedge

They stop the flow of fluid with the help of gates - discs of a cone-shaped shape adjacent to two saddles located at an angle. When the flywheel is actuated, the spindle moves the disk by rotating in the thread of the nut. The tight fit of the disk to the protrusions of the body is due to its wedge-shaped shape and the sealing surfaces of the shutter. This and similar types of valves are used for pipelines transporting water, ammonia, steam, gas, oil products and other substances.

Types of wedges and their features:

• rigid wedge - has increased tightness, which somewhat complicates the conditions for maintenance and operation of valves;
• double-disk wedge - a sophisticated design increases the resistance to wear of the sealing surfaces, improves sealing and reduces the force required to open or close the valve;
• elastic wedge - a modified and simplified device allows you to work effectively in a wide temperature range, body deformations caused by loads on the pipeline are compensated.

Parallel

Such valves with their device differ significantly from those described above. The shutter in them consists of two disks connected by a spacer spring or a wedge. With the introduction of the valve in the "closed" position, the discs are pressed against the seats and stop the flow. The main advantage of parallel stop valves its high reliability serves as the main reason: valves close the jet almost perfectly and therefore can operate in any temperature regime.

Installation of valves for water supply

Exist different ways connections of fittings with pipes: flanged, coupling, socket and welded. The latter is the most reliable and convenient. Also, certain types of valves tend to be fixed on pipes without the presence of separate connecting elements.

When installing shut-off valves, it should be remembered that the valves are installed exclusively with the flywheels up in order to avoid leakage of hydraulic fluid or gas leakage. It is also necessary to ensure that flange connection(if any) was performed smoothly and without distortion.

The widespread use of gate valves in plumbing systems is explained by the fact that they have a simple design, small construction length and are easy to operate. Due to the peculiarities of the structure, they are used in a variety of conditions, and also have low hydraulic resistance, which allows them to work at high speeds of the transported medium.

In water supply and heating systems, wedge valves are a fairly commonly used element. Their main purpose is to block water, Wastewater and neutral liquids. It is worth noting that these elements are used in many areas. In addition to the housing and communal sector, such gate valves are widely used in gas supply systems, for energy oil pipelines, etc. In order not to be mistaken with the choice of shut-off valves of this type, a decision must be made taking into account such parameters as working temperature medium flow, pressure level and operating mode.

Advantages and disadvantages of wedge gate valves

If we consider the features of shut-off valves, we can distinguish a number of its characteristic advantages:

• a simple device that minimizes the likelihood of their failure;
• versatility of use - allows the use of these valves at facilities with various conditions, where they are able to cope with the effects of any pressure temperature;
• low level of hydraulic resistance;
• a wide variety of sizes. Due to this, the consumer has the opportunity to find a product that is most suitable for a particular type of pipe;
• the execution of such fittings allows it to pass the working flow in different directions.

At the same time gate valves have a number of disadvantages to be taken into account at the selection stage:

• the process of opening/closing valves is long in time;
• the presence of a large building height, which is primarily relevant for valves equipped with a retractable spindle;
• low level of maintainability, which is primarily observed in situations where the service life of the used sealing materials ends.

Features of the choice of valves

So that the valves can successfully cope with the tasks assigned to it for a long time, when choosing, you should pay attention to their operating parameters.

Among all the criteria that can be taken into account when choosing, the following deserve the most attention:

Structural design of gate valves

Based on the option of connecting wedge valves to the pipeline, they can be classified into several types:

• welded;
• flanged, in the design of which there may be pairs of connecting flanges, sealing rings and flange plugs.

According to their design, flanged gate valves have the form of shut-off valves equipped with a gate, which, when used, can restrict the movement of the working flow perpendicularly or provide it with free circulation. Valves are designed with two holes, called seats. Such structures are equipped with a locking element made in the form of a wedge-shaped part, which has a narrowing in the lower part.

When the valve is moved to a position that ensures the closing of the valve, overlapping both seats, which are at some angle relative to each other, which helps to prevent penetration into the working environment. The shutter is lifted by a thread, which, when subjected to force, begins to wind: to rotate this element, you can use the handle or use the drive. When the valve is in the open position, the flow can freely pass through it, thereby entering the general pipeline system. According to current regulations, wedge gate valves can be divided into long and short, which is determined by the distance at which the flanges are separated from each other.

One of the popular types of wedge gate valves are full bore, in the design of which the opening of the connecting pipes has the same diameter as the pipeline. For similar products steel and cast iron are used. These models are usually powered by an electric drive. A feature of narrowed wedge gate valves is that their opening is inferior in diameter to the working flow. Although valves of this type are more affordable, they still provide higher hydraulic resistance.

The range of gate valves offered on the market today is represented by products that provide for a manual control option, as well as a control system based on an electric drive, pneumatic and hydraulic drive.

Depending on the nature of the spindle movement, wedge gate valves can be performed in two versions:

• with retractable spindle;
• with fixed spindle.

Rising stem valves

A feature of retractable models is that the thread of the rod is located on the outside of the structure, and the running nut is also located there. In this case, the spindle adjoins the lower end to the shutter. At the moment when the valve begins to open, the nut is turned, which causes the stem to move progressively, while its edge rises to the height of the valve. Such valves have a low level of hydraulic resistance, but at the same time it is easy to get to the control unit with them. Most often they are used in piping systems where the working flow moves at a constant high speed.

Gate valves with fixed stem

Compared to them, gate valves that have fixed spindle, keep the building height unchanged when opening. Due to the fact that the thread is located in the valve structure itself, the opening is carried out by rotating the running nut, which is adjacent to the gate. The running element used in the design is constantly in contact with the working medium, which is why corrosion can pose a threat to such fittings. Due to the fact that it is quite difficult to get to the control mechanism, these types of valves are becoming less and less popular, giving way to shutoff valves equipped with a rising spindle.

Gate wedge type

Based on such a feature as the type of shutter, the considered locking devices can be made in the following versions:

with hard wedge. Here it is imperative to ensure that the shutter angle coincides with the angle between the saddles. This version of the valve is characterized by high tightness, which is associated with the features of its design. At the same time, it has its drawbacks, the main of which should be called the difficulties that arise when it is necessary to fit the wedge to the saddles, as well as the risk of jamming the valve when operating such valves.

Temperature fluctuations can adversely affect the operation of the device, which may make it difficult to open it. Negative factors include corrosion, as well as an insignificant service life of the sealing material, which can also lead to a similar result.

Double disc version. The design of the shutter is represented by two discs, which are arranged obliquely with respect to each other, forming a wedge. Thanks to this version of the valve, the conditions for high-quality sealing of the gate valve and the selection of the required position of the disks in relation to the seats appear, on which violations of the accuracy of the hole dimensions are no longer able to have a significant impact.

Speaking about the advantages of this embodiment, it should be noted a high level of resistance to wear, no difficulty in opening shut-off valves and a high level of tightness. When using the Hawle double disc wedge valve, the high level of sealing of the pipeline is clearly demonstrated and at the same time the high resistance of the sealing material to wear is ensured.

With elastic wedge. Such a design is characterized by the use of a movable mounting of disks, in which leading role performs an elastic element. This makes it possible to achieve the maximum density of the gate, which does not change its position even under the influence of loads and temperature fluctuations from the working flow. Of the advantages that valves of this design have, one should first of all single out a long service life.

If we analyze the range of wedge gate valves, we can distinguish the following types:

• steel;
• cast iron;
• fittings based on alloys made using casting or welding technology.

Cast iron wedge gate valves are ideal for many types of pipelines. Similar designs are widely used in fire extinguishing systems, water supply and steam movement. Given the low level of hydraulic resistance that is inherent in cast iron, unimpeded circulation of the working flow through the open saddle holes of the cast iron wedge valves is ensured.

Conclusion

To ensure the normal operation of piping systems, it is necessary to use an element such as a wedge valve. However, the most important thing is that this shut-off valve is correctly selected. It is necessary to take into account not only the operating conditions, but also structural design the element itself. This will subsequently affect not only the flow capacity of the valves, but also the efficiency of the system and the service life of the valves themselves. The material used is also an important selection factor, which to a large extent can determine the final choice.

Slide gate valves are gate valves in which the sealing surfaces of the gate elements are mutually parallel.

1.3 Pinch valves

gate valve- type, designed to cover a non-aggressive working environment, mainly with high temperatures and pressures.
Locking element in gate valves it moves perpendicular to the axis of the flow of the working medium.
Flow shutoff occurs due to the translational-rotational movement of the spindle, which moves the wedge from the upper position to the lower one.
Unlike valves and gate valves that open when the spindle is rotated 90°, gate valves are multi-turn valves. The smooth gradual shutoff of the flow ensures that there are no sudden pressure drops, and the smooth opening prevents the occurrence of water hammer. It is because of these properties that valves are used mainly in main technological and transport pipelines with diameters from 15 to 2000 mm.

According to the design of the shut-off valve, gate valves can be divided into wedge and gate valves.

IN wedge gate valves saddles in the body are located at a slight angle to each other, and the shutter is a device in the form of a wedge - rigid, elastic or double-disk, which in the "closed" position fits tightly into the space between the saddles. Over time, the tightness of such a valve may be compromised due to strong friction in the extreme closed position.

Gate valves with rubberized wedge are a modification of wedge gate valves. have a smooth full passage, due to which there is no strong friction at the moment of shutting off the working flow. The rubberized wedge of the gate valve is designed to provide high levels of tightness and strength, as well as uninterrupted operation of valves, even with sudden drops temperature regime. Another feature that is characteristic of this type of gate valves is the low operating torques.

Gate valves are a type of parallel valve. are used in cases where one-way direction of the flow of the working medium is allowed and high tightness of the shut-off body is not required. They are intended for installation as locking devices on pipelines transporting sewage, sludge and other media contaminated with mechanical impurities. Sometimes the valve is made with a knife to destroy particles in the working environment, in this case the valves are called knife gate valves.

Of great importance for the operation and scope of valves is the location of the running unit. It can be located inside the valve in the working environment or outside the body cavity. In other words, valves come with rising stem and non-rising stem.

Rising stem valves:

In gate valves with rising stem spindle thread and spindle nut are located on the outside of the valve body. The lower end of the spindle is connected to the shutter, and when the spindle nut is rotated to open the valve, it performs only translational movement together with the shutter, while the upper end of the spindle extends by the value of the shutter stroke. To enable the spindle to move, the travel nut is raised above the upper part of the cover (that is, above the stuffing box) by approximately the amount of stroke in the design, which is called the yoke assembly.

The advantages of this design are the absence of harmful effects of the working environment on the chassis and free access for it. Maintenance, and consequently less wear of the stuffing box and higher reliability of the threaded pair and stuffing box.
The disadvantage of such gate valves is the increase in construction height and weight due to the spindle exit from the cover by at least the diameter of the passage and the need for this reason to leave free space for the spindle exit during installation.

Gate valves with non-rising stem:

In gate valves with non-rising stem the lead thread is located inside the cavity of the valve and when opening the spindle does not move out of the cover, maintaining its original position in height. The running nut in these gate valves is connected to the gate and, when the spindle is rotated to open the passage, it seems to be screwed onto it, dragging the gate with it.
In gate valves with a non-rising stem, the running unit is immersed in the working environment and therefore exposed to corrosion and abrasive particles in the working environment, access to it is closed and there is no possibility of maintenance during operation, which leads to a decrease in the reliability of the running and stuffing box units.

In this regard, such gate valves are of limited use - for pipelines transporting mineral oils, oil, water, which are not clogged with solid impurities and do not have corrosive properties. Since gate valves with a non-rising stem make it difficult to monitor and maintain the bogie assembly, they are not recommended for critical installations.
The advantage of this design is the lower construction height, which makes it expedient to use them for underground utilities, wells, oil wells etc.

The main advantages of valves:

• comparative simplicity of design, low hydraulic resistance;
• relatively small building length;
• the symmetry of the valve allows you to pass the working flow in any direction;
• possibility of application in various conditions operation, high tightness;
• wellless installation, long service life under adverse conditions;
• the possibility of repair and replacement of components in case of their breakdown or wear;
• low torque when controlling the electric drive;

Gate valve applications:

Gate valves are mainly used in main pipelines, in housing and communal services, gas and water supply systems, oil pipelines, energy facilities and many others, to shut off working environments with high temperature and pressure.

Masterprom company implements by classifying them by application: , paper and pulp industry, pipelines of petroleum products, abrasives, industrial fluids. Manufacturers of gate valves Jafar, Stafsjo, Hawle, Orbinox, MZTA, Granar have been on the pipeline valve market for a long time, product quality and delivery time are justified by reasonable prices, all products are certified and comply with international standards.

Gate valve automation, additional equipment:

Using its own production capabilities and developments, Masterprom offers its services for pipeline valve automation- installation of electric drive equipment of imported and Russian production. For joining the electric drive and manually operated gate valves, special ones are used for gate valves with a rubberized wedge, and for gate valves with a rising stem.

It's also possible stem extension valves in cases where installation of the electric drive directly on the valve is not possible, for example, due to a narrow well. A series of rod extensions ShFV () allows you to install the drive at a height of up to 3500 mm, a series of rod extensions ShTN () allows you to adjust the mounting point of the electric drive within 500 mm with a maximum height of 3500 mm.

To automate a wellless gate valve, Masterprom has developed a special one that allows you to install an electric drive at a height of 500 - 800 mm above the ground.