Floating ball valve design details revealed

Floating Ball Valve is a type of ball valve widely used in industry, known for its simple structure, reliable sealing and convenient operation. Compared with fixed ball valve, floating ball valve is more suitable for small and medium caliber, low to medium pressure occasions.
1: Floating ball valve design details revealed
1. Ball structure: floating suspension type
The ball is not fixed at the bottom by a support shaft, but is clamped by the valve seats on both sides, and is slightly "suspended" in the valve body.
When subjected to fluid pressure, the ball will move slightly along the flow direction of the medium, thereby pressing the valve seat on the outlet side to achieve self-sealing.
Advantages:

Simple structure and few parts.
Automatic compensation seal, with certain self-adjustment ability.
2. Connection between valve stem and ball: flat head or pin type
The valve stem and ball are usually connected by a flat head insertion structure or a pin to facilitate the transmission of rotational torque. The ball rotates to open and close, and can be fully opened or fully closed at 90°, which is convenient to operate.
Note: To prevent the design of "valve stem falling off", the reverse thrust protection structure needs to be considered.
3. Sealing structure design: Commonly used are soft sealing structures (PTFE, RPTFE, PPL, etc.).
High-end products can be equipped with metal hard seals, which are suitable for high temperature or abrasive media. Since the ball can move forward and press against the outlet valve seat, the sealing surface requirements are relatively high.
2: Technical points:
The outlet valve seat needs to have a certain elasticity (spring or preload design) to adapt to the displacement of the ball.
4. Anti-static design
A conductive spring or contact pin is installed between the metal ball and the valve stem to ensure that static electricity can be discharged to the valve body to prevent sparks from igniting the medium.
Especially important: Suitable for occasions where flammable and explosive gases or liquids are transported (such as natural gas, gasoline, olefins, etc.).
5. Blow-out proof valve stem design
The valve stem is inserted from the outside of the valve body, and there is a positioning shoulder or limit ring inside the valve body to prevent it from being blown out under pressure.
Comply with safety regulations such as API 607.
6. Bidirectional sealing / one-way sealing
Most floating ball valves are one-way sealing by default (the outlet side valve seat is pressed by the fluid).
If bidirectional sealing is required, a spring-loaded structure or a double floating seal ring is required.
7. Fire-safe Design
After the soft seal is burned, the metal-to-metal contact can still achieve basic sealing function.
This is achieved through special seal seat support and secondary seal design, in line with API 607 ​​/ ISO 10497 and other standards.