Despite its apparent simplicity, the water valve is a relatively complex design, the build quality and reliability of which directly affect the working process when supplying water. In this regard, all valves, valves and other elements must comply with certain standards, to ensure the performance of the required tasks. Consider the features of these parts and their characteristics.
Varieties
Water valves can be parallel or wedge type. In the first case, the sealing part of the shutter is placed in parallel, without the formation of any angle. Such modifications are divided into single and double disc variations.
A wedge locking device provides overlapping strokes by shifting the shutters perpendicular to moving flows. Such modifications are used in servicing pipelines with water, steam, gases, and some petroleum products. Wedges can be solid, elastic, or in the form of twin discs coated with high alloy steel. The design facilitates the replacement of gaskets during the construction of the system or its maintenance.
Spindles
Depending on the type of water valve, it is equipped with a block with different direction of movement of the spindles. This plan provides for two types of configurations:
- Retractable spindle. In this case, the opening and closing of the valves is carried out using translational or helical movements. Such elements, as a rule, have impressive dimensions.
- Non-retractable rotating counterpart. This element is smaller in height, it is usually used when transporting water, oil products and other liquids that do not cause corrosion processes. The remaining flows are transported through gate valves with a sliding spindle.
The locking device in the design is a steel partition with various parameters, which is in demand when gas and liquid are shut off in the event of a difference in pressure indicators.
Principle of operation
The water valve is designed to turn on or off the flows of the medium used. Temperature exposure - up to 225 degrees Celsius. A cast-iron element on horizontal pipelines is mounted upward by handwheels with vertical spindles.
On a vertical structure, the valve is installed flat, and the spindles look horizontally. All types of locking devices considered are of the types of products being repaired. In any configuration, the possibility of manual or automatic control (by means of an electric drive) is provided .
The second modification is more convenient and practical, thanks to its wider functionality. Using the buttons, you can stop the water valves in any intermediate positions. In addition, automatic engine deactivation occurs when the locking mechanisms reach the extreme points. An optional shutter position sensor allows you to see if the passage is open or closed.
Features
Among the advantages and features of this mechanism, the following points can be noted:
- When using this part, the flow of the transported stream is carried out in any direction.
- The element has a short construction length.
- The ability to shut off liquid and viscous flows with little hydraulic resistance is observed.
- Withstanding pressure - up to 25 MPa.
- Possible diameter fluctuations (DN) - 50-1200.
- The temperature limit is up to 450 degrees.
- As a working medium, not only water can act, but also oil, acids, alkali, and petroleum products.
Cast Iron Water Gate Valve
Such a locking device is widespread and used in pipelines with nominal diameters of passages from 50 millimeters to 3 meters. The modification is distinguished by its simplicity of design and the presence of a small hydraulic resistance. The last parameter is determined by a handwheel with a manual drive, providing a shift of the valves up to the absolute overlap of the gaps.
Depending on the design features, the device of water valves can be full bore or narrowed. The first option is characterized by lower hydraulic resistance, as well as the presence of a larger diameter. Reduced versions are mainly used in systems where the working fluid moves at set speeds.
A distinctive element of the cast-iron locking elements is a retractable spindle, which helps to facilitate maintenance due to convenient access to structural components.
A configuration without retractable rods also has its advantages. The main one is a compact size that allows you to place the part in small compartments (1.5 times smaller than the previous element).
Steel analogues
Water flanged gate valves made of steel are operated in open / closed modes. They are used as control valves in the presence of an open-type hydraulic system with a nominal pressure of up to one atmosphere.
The products in question are classified by the following parameters:
- Type of drive.
- Placement of running nodes.
- The method of connection to the pipeline.
- Types of shutters.
Steel wedge-shaped gate valve, in turn, is divided into rigid and composite modifications. In the first version, one-piece wedges are provided that provide good tightness. Their disadvantage is that when significant temperature fluctuations occur, the elements are subject to jamming. To avoid this, a valve with a double-disk locking mechanism has been created.
Pipe connection
Fixation of water valves, the diameter of which corresponds to the pipeline, is carried out using flanges and bolts or by welding. The second method is considered stronger and more reliable; it is used for processing structures with aggressive fluids. At the same time, there is the exclusion of leaks and excellent tightness. Despite the small dimensions, the installation of gate valves requires care and accuracy.
According to the manufacturing method, the valves considered are divided into the following categories:
- Solid cast modifications.
- Welded options.
- Stamped counterparts.
The most common cast gate valves, as they are the most reliable. Their advantages include ease of use, low hydraulic resistance and short length. Among the minuses - a long period of opening and closing, as well as the presence of high altitude. With their help, it will not be possible to adjust the flow rate of the working fluid.
Installation Recommendations
Regardless of the types of water valves, they have similar rules that must be observed during installation. It is necessary to choose a system taking into account the features of operation. For example, if the shut-off elements are installed in pipelines with a gradual decrease in working flows, the body parts of the parts experience high-frequency vibrations with incomplete gates. This provokes intense wear and tear, up to failure. As a result, it will be necessary to disassemble the entire structure, perform a complete replacement and lapping of the valves.
The following factors influence the duration of a working resource:
- Correct installation.
- Preparation of work planes and operating environment.
Before installing the valves, it is recommended that the surfaces be steamed with hot water, after which they must be dried. Previously, the pipeline itself should also be cleaned of foreign particles and dirt. Mounted elements must comply with the technical data sheet. Otherwise, the product will quickly become unusable.
Useful Tips
Installation of latches by a flywheel down is not allowed. This leads to the flow of working fluids or the evaporation of gas.
With a flange connection, it is necessary to ensure that all aggregating elements are aligned without distortions.
Before mounting the shutoff valves, pipes and other assembled elements must be thoroughly cleaned from rust, oil, dirt, foreign particles. Only such an approach can guarantee high quality installation and a long working life.
In conclusion
It is worth noting that the price of water gate valves depends on the size and material of manufacture, as well as on the configuration. The average cost of such a locking mechanism is from 5 to 60 thousand rubles. Regardless of the types of elements under consideration, they play an important role in the design of pipelines for various purposes. The main thing - when choosing to take into account the features of operation, working fluid and installation features.