Come funziona la valvola a globo

The principle of operation of a gate valve is to close the passage cross-section with a movable gate that tightly fits against a stationary seat in the valve body. The gate is hinged on a threaded stem, perpendicular to the axis of the pipeline.

Rotating the handwheel through a stationary nut in the valve body translates into linear movement of the stem, which moves the gate. In the fully closed position, the gate completely blocks the passage cross-section, while in the fully open position, it completely opens it.

Depending on the design of the gate valve, the stem may be located perpendicular to the axis of the pipeline or inclined relative to it. Valves with inclined stem positions, also known as 'slanted' valves, have a higher flow capacity than valves with straight stems.

Since several turns of the handwheel are required to close a gate valve, some manufacturers do not exclude the possibility of using the valve to throttle flow or balance heating systems. However, it should be noted that a valve is primarily a shut-off device, and its use for regulation is not allowed by regulations.

The tightness of the closure of the passage cross-section in a gate valve is ensured by metal-to-metal sealing, and in some designs, additional sealing rings made of fluoroplastics or rubber are attached to the gate.

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