Come funziona la valvola a sfera

A shutter is attached to a vertical stem, made in the form of a ball with a through hole. The diameter of the hole is equal to the internal diameter of the connected pipeline. In the open position, the axis of the hole coincides with the axis of the pipeline, and to close it, it is necessary to rotate the stem by 90 degrees, in which case the ball also rotates, and the axis of the hole becomes perpendicular to the direction of the flow.

The tightness of the closure is ensured by fluoroplastic sealing rings that are pressed against the polished surface of the ball by a disk spring or fastening bolts in welded and flanged valves, and by a threaded connection of the body in sleeve valves.

For manual control of the ball valve with a diameter of up to DN125, handles are used, and for larger diameters, gear drives are used. To limit the extreme positions of the shutter, stops are provided in the body.

If remote control is required, rotational electric drives with high torque are installed on ball valves of any size. The need to use drives with high torque is due to the fact that the full cycle of opening/closing occurs with only a 90-degree rotation of the stem and requires significant effort.

During operation, the ball valve must be either fully open or fully closed. Operating the valve with an intermediate position of the shutter is not allowed, as abrasive wear of the ball can lead to a violation of the tightness of the closure.

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