Shut-off, control and safety valves are an important component of almost any pipeline designed to transport liquid and gaseous substances. One of the popular options are ball valves, which have excellent performance and technical characteristics. They are actively used in the process of creating or repairing pressure systems in the petrochemical industry, public utilities, as well as in other areas of industrial and economic activity.
The principle of operation
A characteristic feature of ball-type devices, and not only fitting, the fact that they can be used as shut-off and control valves stands out. That is, using it, you can both completely block the flow of the working medium, and reduce or increase its supply. At the same time, it should be taken into account that the use as control equipment is unacceptable on highways transporting liquids at high speed. This is justified by the appearance of cavitation at the intermediate positions of the locking mechanism. The main components of a ball valve are:
- body;
- spherical locking mechanism;
- sealing seats;
- device spindle ;
- handle for control.
When operating a metal product, to completely stop or resume the movement of the product, it is enough to turn the spherical element ninety degrees to the right or left. To ensure tightness in valves, sealing seats based on polymeric materials (for example, fluoroplastic) are most often used.
By type, the products are divided into full bore and reduced ones. In the first case, it is assumed that the passage in the closing ball has the same diameter as the pipeline. In the second, the cross section of the hole in the ball is at least one size smaller.
Depending on the purpose and technical capabilities, control can be carried out manually or by means of an electric drive. Pneumatic actuator is also in demand.
Structural differences
Unlike flanged or welded types of similar pipeline valves, ball valves of the category under consideration equipped with fittings, which ensure that the PTFE seats are pressed against the obturator. Installation of the product into the pipeline system is carried out by means of special nipples for welding, which, in turn, are attached directly to the valve body using union nuts. This design greatly simplifies installation work.
Fundamental advantages
In-line ball valves are very popular due to a number of advantages, among which are:
- high tightness index corresponding to class A;
- small linear length;
- simple maintainable design;
- insignificant time spent on determining the meta position closing component.
Stainless and carbon steels can be used in the production process. Accordingly, the temperature range varies from -60 to +160 degrees. The total average service life is at least 8000 cycles.
