Ball Valves - A Variety of Pipeline Cranes

Among the locking devices are ball valves, without which it is impossible to imagine the pipelines used to transport gaseous and liquid petroleum products, natural gas, drinking and industrial water, alkalis and acids. The tap itself is a kind of pipeline armature, for which a working element of a spherical shape is characteristic. Such a constructive solution is not a novelty, and has been used for a century, but the cranes of this variety have only recently become truly durable and reliable.

Now at the time of production of ball valves, ultra-modern materials such as fluoroplastic and synthetic rubber have been used. This made it possible to significantly simplify the design of pipeline cranes, as well as significantly extend the operating time of these devices. As a bolt of the ball valve protrudes a metal ball, and along its axis a through hole is made through which the working medium can pass. In a situation where the diameter of this hole is equal to the internal diameter of the pipeline, the tap is called full-bore. If it is smaller, the tap is called incomplete.

Usually the bolt is in the saddle, which consists of fluoroplastic washers adjacent to it rather tightly, however, when controlling the device, a minimum force is provided. The ball valve is characterized by two extreme positions, and the position of the shutter is changed due to the rotation of the special handle. In this case, ball valves can be used as a control and strong shut-off valve. Among ball valves, you can choose a model where the bolt is able to move only within strictly defined limits due to the pressure of the working medium, and in other models the bolt is fixed rigidly in special supports.

The spherical "floating" plug is firmly pressed against the soft sealing ring located on the outlet side, which ensures maximum sealing of the device. But for this variety of ball valves there is a fairly high hydraulic resistance, so such a stop valve can only be used in pipelines of a relatively small diameter. All the locking elements installed in the supports are reliable, and they require a minimum force to control them, but their design remains rather complicated.

At the bottom of the locking element is an axial protrusion, which is mounted to the ball valve body by means of plain bearings or rolling bearings . Advantages of ball valves include simplicity of design, maximum convenient control, small dimensions, reliable and high tightness, simple shape of the flowing part, complete absence of any stagnant zones in it. To turn the crane you have to spend a little time, and the shut-off valve can be used for contaminated and all kinds of viscous media, slimes and pulps, various suspensions.

The disadvantage of ball valves, in the design of which provides a cantilever handle, is the presence of a "dead" zone, located at the turn, and models with a handle-lamb are deprived of such a minus. In full-flow type valves, the ball itself must be turned to open or close the passage completely. If the valve is fully open, when hydraulic fluid flows through it, the hydraulic losses remain negligible. Such a valuable property made this stop valve an important device located on the main gas pipelines in the linear part.

To reduce the torques and dimensions required at the time of valve control, narrowed cranes are often used, so the complexity of using the process system can be substantially minimized.

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