Working Principle and Structure Analysis of Threaded Ball Valves

As a common fluid control device, threaded ball valves are widely used in various small-diameter pipeline systems. Due to their simple structure, good sealing performance, and ease of operation, they perform exceptionally well in low and medium-pressure environments.

Working Principle of Threaded Ball Valves

The core component of a threaded ball valve is a ball with a circular passage, which is rotated by the stem. When the valve is in the open position, the passage of the ball aligns with the pipeline direction, allowing fluid to flow freely through the passage. When the valve is closed, the ball rotates 90 degrees, making the passage perpendicular to the pipeline direction, thus stopping the flow of fluid. Through this simple rotational movement, the threaded ball valve enables rapid on-off control of the fluid flow.
The operation of a threaded ball valve typically requires only a 90-degree rotation of the stem to complete the opening and closing actions, making it simple to operate and providing rapid actuation. Because the ball can tightly contact the seat when closed, it achieves a good sealing effect, preventing media leakage.

Structure Analysis of Threaded Ball Valves

Threaded ball valves consist of several key components. The following is an analysis of their main structure:

1. Body

The body is the main outer shell of the threaded ball valve, typically made from materials such as stainless steel, brass, or plastic. The body connects to the pipeline through internal or external threads.

2. Ball

The ball is the core component of the threaded ball valve, typically made from stainless steel or brass. It features a spherical passage through which the fluid flows. The surface of the ball is usually precisely machined to ensure a tight fit with the seat, providing excellent sealing performance.

3. Stem

The stem connects the ball to the handle, responsible for transmitting the rotational motion of the handle to the ball, enabling it to rotate 90 degrees. The stem is typically designed with a blow-out proof feature to prevent it from being pushed out of the body by the medium under high pressure or in the event of a failure.

4. Seat

The seat is located inside the valve body and comes into contact with the ball. It is typically made from soft sealing materials such as polytetrafluoroethylene (PTFE), which offer excellent corrosion resistance and sealing performance. The tight contact between the seat and the ball ensures effective sealing of the threaded ball valve when closed.

5. Handle

The handle is the component used to operate the threaded ball valve. By rotating the handle, the user can directly control the open or closed state of the ball. The handle typically features indicators to show the switch position, making it easier for operators to determine the valve's open or closed status.

Advantages and Applications of Threaded Ball Valves

Threaded ball valves are widely used in fluid control applications such as residential water supply systems, commercial buildings, and small industrial equipment due to their simple structure, ease of operation, and excellent sealing performance. The installation process is straightforward, requiring no complex equipment or tools—just tightening the threads to complete the connection. Additionally, the compact design of threaded ball valves allows them to function effectively in confined spaces, making them particularly suitable for situations with strict space requirements.
 
However, because the strength and sealing performance of threaded connections may not be as effective as flanged connections in high-pressure and high-temperature environments, threaded ball valves are typically used only in low and medium-pressure systems.