Shutoff and regulating fittings. Pipe fittings. Types of pipe fittings. Gate valves for water supply as a tool for water supply management

In order to find out what type of reinforcement is better to choose, you need to know its main advantages and 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 the space (working area) in which the shutter is located. On the body are two ends with which the part is connected to the pipeline. These elements can be coupling, threaded, as well as for welding. The housing design contains protrusions called saddles. When closing the valve, the sealing parts of the shutter are pressed against the seats, preventing the liquid from overcoming the working area.

An element that facilitates the movement of the shutter is called a spindle. The mechanism for moving the spindle through a threaded nut is:

• tame
• automated (using electric drive).

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

Types of valves for water pipes

Wedge

They carry out the termination of the fluid supply with the help of valves - cone-shaped disks 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 housing 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.

Varieties of wedges and their features:

• hard wedge - has increased tightness, which somewhat complicates the conditions of service and operation of the reinforcement;
• double-disk wedge - a complicated design increases the resistance to wear of the sealing surfaces, improves sealing and reduces the necessary force to open or close the valve;
• elastic wedge - a modified and simplified device that allows you to work effectively in a wide temperature range, compensate for the deformation of the body caused by loads on the pipeline.

Parallel

Such valves with their device differ significantly from the above. The shutter in them consists of two disks connected by a spacer spring or wedge. When the reinforcement is in the closed position, the discs are pressed against the seats and stop the flow. The main advantage of parallel shutoff valves is its high reliability: gate valves block the stream almost perfectly and therefore can work in any temperature mode.

Installation of valves for water supply

There are different ways of connecting fittings with pipes: flange, coupling, socket and welded. The latter is the most reliable and convenient. Also, certain types of valves have the property 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 by the handwheels upwards, in order to avoid hydraulic fluid leakage or gas leakage. It is also necessary to ensure that flange connection   (if any) was performed smoothly and without distortion.

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

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

Advantages and disadvantages of wedge gate valves

If we consider the characteristics of valves, we can distinguish a number of characteristic advantages:

• a simple device, due to which the probability of their failure is minimized;
• universality of application - allows the use of this stop valve on objects with various conditions, where they can 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 reinforcement allows it to pass the work flow in various directions.

At the same time, wedge gate valves have a number of minusesto be considered at the selection stage:

• the process of opening / closing gate valves is time-consuming;
• the presence of a large construction height, which is primarily relevant for valves, equipped with a retractable spindle;
• low maintainability, which is primarily observed in situations when the operational life of the used sealing materials ends.

Features of the choice of valves

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

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

Valve design

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

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

According to their design, the flanged valves have the form of shut-off valves equipped with a shutter, which, when used, can perpendicularly restrict the movement of the working flow or provide it with free circulation. The design of the valves provides two openings called saddles. Such designs 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 valve closes, overlapping both saddles, which are at a slight slope relative to each other, which helps to prevent penetration into the working environment. The shutter is lifted by a thread, which, under the influence of forces, begins to wind up: you can use a handle to rotate this element or use a drive. When the valve is in the open position, the flow can freely pass through it, thereby falling into 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 removed from each other.

One of the popular types of wedge gate valves are full bore valves, in the construction 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 driven by an electric drive. A feature of narrowed wedge gate valves is that their opening is inferior in diameter to the work flow. Although gate valves of this type are more affordable, they still provide higher flow resistance.

The assortment of gate valves currently available on the market is represented by products that provide a manual control option, as well as a control system based on an electric drive, pneumatic and hydraulic actuator.

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

• with extendable spindle;
• with fixed spindle.

Spindle Gate Valves

A feature of the retractable models is that the stem thread 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 twisted, which causes the stem to move progressively, while its edge rises to the height of the shutter. Such shutoff 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 work flow moves at a constant high speed.

Fixed Spindle Gate Valves

Compared to them, valves that have fixed spindlekeep construction height unchanged when opened. Due to the fact that the thread is located in the design of the valve, the opening is carried out by rotating the spindle nut, which is adjacent to the valve. The running element used in the construction is constantly in contact with the working medium, which is why corrosion can pose a threat to such valves. Due to the fact that it is quite difficult to get to the control mechanism, such types of valves are becoming less and less popular, giving way to shut-off valves equipped with a retractable spindle.

Type of valve wedge

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

With a hard wedge. Here it is imperative that the shutter angle coincides with the angle between the saddles. This version of the valve has a high tightness, which is associated with the features of its design. At the same time, it has its drawbacks, the main of which are the difficulties that arise when it is necessary to fit the wedge to the saddles, as well as the risk of jamming the shutter during operation of such valves.

Temperature fluctuations can negatively affect the operation of the device, which may cause difficulties with its opening. Negative factors include corrosion, as well as an insignificant operational life of the sealing material, which can also lead to a similar result.

Double disc design. The shutter design is represented by two discs, which are arranged obliquely with respect to each other, forming a wedge. Thanks to this embodiment of the shutter, conditions arise for high-quality sealing of the valve and the selection of the required position of the discs in relation to the seats, which can no longer be significantly affected by violations of the accuracy of the hole dimensions.

Speaking about the advantages of this embodiment, it is necessary to note a high level of resistance to wear, the absence of difficulties when opening shut-off valves and a high level of tightness. When using a wedge gate valve of a double-disc Hawle, a high level of sealing of the pipeline is clearly demonstrated and at the same time a high wear resistance of the sealing material is provided.

With elastic wedge. Such a design is characterized by the use of a movable disk mount, in which the elastic element plays the main role. This allows you to achieve maximum closure density of the shutter, which does not change its position even under the influence of loads and temperature fluctuations from the side of the work flow. Of the advantages possessed by valves of this design, it is first of all necessary to single out a long service life.

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

• steel;
• cast iron;
• reinforcement 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 transfer. Given the low level of hydraulic resistance that is inherent in cast iron, the unimpeded circulation of the working flow through the open saddle holes of the wedge shut-off valves made of cast iron is ensured.

Conclusion

To ensure the normal operation of piping systems, it is necessary to use an element such as a wedge gate valve. However, it is most important that this stop valve is correctly selected. It is necessary to consider not only operating conditions, but also structural design   the element itself. This subsequently affects not only the throughput capacity of the shutoff valves, but also the efficiency of the system and the service life of the shutoff valves itself. The material used is also an important factor of choice, which to a large extent can determine the final choice.

Gate valves are gate valves, in which the sealing surfaces of the shutter elements are mutually parallel.

1.3 Hose gate valves

Gate valve   - A type designed to shut off a non-aggressive working environment, mainly with high temperature and pressure.
Locking element   in valves it moves perpendicular to the axis of the flow of the working medium.
Flow overlap   occurs due to the translational-rotational movement of the spindle, which moves the wedge from the upper position to the lower.
  Unlike cranes and shutters that open when the spindle is rotated 90 °, the valves are multi-turn valves. Smooth gradual blocking of the flow ensures the absence of sudden pressure drops, and smooth opening prevents the occurrence of water hammer. It is precisely because of these properties that gate valves are used mainly in main technological and transport pipelines with diameters from 15 to 2000 mm.

According to the design of the locking body, the valves can be divided into wedge and slide valves.

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

Rubber wedge gate valves   are a modification of wedge gate valves. have a smooth full passage, so that at the time of the overlap of the work flow there is no strong friction. The rubberized wedge of the gate valve is designed to provide high tightness and strength, as well as uninterrupted operation of shutoff valves, even with sudden changes temperature condition. Another feature characteristic of this type of gate valve is its low control torques.

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

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

Retractable Gate Valves:

At the gate with extendable stem   spindle thread and running nut are located outside the valve body. The lower end spindle is connected to the shutter and, when the spindle nut is rotated, only the translational movement together with the shutter is made with the shutter, while the upper end of the spindle extends by the shutter stroke value. To allow the spindle to move, the travel nut is raised above the top of the cover (i.e., above the gland) by approximately the amount of shutter travel in the structure, which is called the yoke.

The advantages of this design are the absence of harmful effects of the working environment on the chassis and free access for it maintenanceand, consequently, less wear of the stuffing box packing and higher reliability of the threaded pair and stuffing box.
  The disadvantage of such valves is an increase in the construction height and weight due to the spindle coming out of the cover not less than by the diameter of the passage and the need for this reason, during installation, leave free space for the spindle to exit.

Gate Valves:

At the gate with non-rising stem   the running thread is inside the valve cavity and when opening the spindle does not extend out of the cover, retaining its original height position. The running nut in these gate valves is connected to the valve and, when the spindle rotates to open the passage, it is as if screwed onto it, dragging the valve along with it.
  In valves with a non-rising spindle, the running unit is immersed in the working environment and therefore subject to corrosion and abrasive particles in the working environment, it is closed to access and there is no possibility of maintenance during operation, which leads to a decrease in the reliability of the running and stuffing units.

In this regard, such valves are of limited use - for pipelines transporting mineral oils, oil, water, not clogged with solid impurities and not having corrosive properties. Since in valves with a non-rising spindle it is difficult to observe and maintain the running gear, they are not recommended for critical facilities.
  The advantage of this design is a lower construction height, which makes them suitable for underground utilities, wells, oil wells, etc.

The main advantages of gate valves:

• comparative simplicity of design, low hydraulic resistance;
• relatively short construction length;
• the symmetry of the valve allows you to pass the work flow in any direction;
• possibility of application in various operating conditions, high tightness;
• bezdelodezny installation, long service life under adverse conditions;
• the possibility of repair and replacement of components in case of breakage or wear;
• low torque when controlling an electric drive;

Scopes of gate valves:

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

Masterprom realizes by classifying them by application:, paper and pulp industry, pipelines of petroleum products, abrasive materials, industrial liquids. Valve manufacturers Jafar, Stafsjo, Hawle, Orbinox, MZTA, Granar have been in the pipeline valves market for a long time, product quality and delivery times are justified by reasonable prices, all products are certified and meet international standards.

Gate valve automation, optional equipment:

Using its own production capabilities and best practices, Masterprom offers its services in automation of pipe fittings   - installation of electric drive equipment of imported and Russian production. For joining the electric drive and manually operated gate valves, special valves are used for valves with a rubber wedge, and for gate valves with a retractable stem.

Also possible rod extension valves in cases where the installation of an electric actuator directly on the valve is impossible, for example, due to a narrow well. A series of ShFV rod extension cords () allows the drive to be installed at heights up to 3500 mm, a series of ShTN rod extension cords () allows you to adjust the mounting point of the electric drive within 500 mm at a maximum height of 3500 mm.

To automate the valveless shutter, Masterprom developed a special one that allows you to install an electric actuator at a height of 500 - 800 mm above the ground.