How Does Ball Valve Open and Close?

A ball valve is a common industrial valve widely used in various pipeline systems due to its quick operation, ease of use, and excellent sealing performance. But how does a ball valve achieve opening and closing?

1. Basic Opening and Closing Principle

The core component of a ball valve is a spherical closure (ball) with a through-hole, which controls fluid flow by rotating 90°. Its working mechanism is as follows:

(1) Open Position

When the through-hole of the ball is aligned with the pipeline, fluid can flow freely, and the valve is fully open.

(2) Closed Position

When the ball rotates 90° so that the through-hole is perpendicular to the pipeline, the solid surface of the ball seals tightly against the valve seat, blocking fluid flow and fully closing the valve. This simple and efficient opening and closing mechanism allows for easy operation and enables rapid switching of fluid flow.

2. Opening and Closing Methods of Ball Valves with Different Actuation Types

Based on the actuation method, ball valves are commonly classified into three types: manual, pneumatic, and electric.

(1) Manual Ball Valve

Operated via a handle or gear mechanism, rotating 90° clockwise to close and 90° counterclockwise to open.

(2) Pneumatic Ball Valve

Uses compressed air to drive an actuator, which rotates the ball through a piston or diaphragm mechanism. This type is suitable for rapid switching control.

(3) Electric Ball Valve

Powered by an electric motor, enabling ball rotation. It can be integrated with automated control systems for remote operation and precise flow regulation.

3. Opening and Closing Characteristics of Different Ball Valve Structures

(1) Floating Ball Valve

The ball is pressed against the downstream seat by fluid pressure, forming a seal. It is suitable for medium- and low-pressure systems.

(2) Trunnion Ball Valve

The ball is supported by upper and lower bearings, making it unaffected by fluid pressure. This design is ideal for large-diameter and high-pressure applications.

(3) V-Port Ball Valve

The ball has a V-shaped port, allowing flow regulation and making it suitable for throttling control.

4. Opening and Closing Speed & Service Life

Ball valves typically have a short opening and closing time, with standard manual ball valves completing the switch in just 1–2 seconds. Due to minimal friction on the sealing surfaces, ball valves generally have a long service life. However, in applications involving frequent operation, high temperatures, high pressure, or corrosive environments, regular maintenance is necessary to ensure reliable performance.