What Is The Difference Between A Floating Ball Valve And A Fixed Ball Valve?

Floating ball valves and fixed ball valves are very different in structure design, operating principle, suitable working conditions, working performance, sealing performance, etc., as follows:
I. Structural design
Floating ball valves
Sphere support: The sphere has no fixed shaft support and floats freely within the valve body. It is only connected to the lower stem, while the upper stem conveys torque.
Sealing Method: Fluid pressure pushes the ball onto the outlet seat, achieving a single-side sealing (usually at the exit). Seats are fixed.
Structure characteristics: simple overall structure, compact size, thin valve body, small size.
Fixed ball valve
Sphere support: The sphere is fixed to the valve valve body by the upper and lower stem, supported by bearings, and has a fixed position.
Sealing Method: Seat removable. Spring preload or fluid pressure pushes the seat toward the ball seal, achieving a double-side sealing.
Structural characteristics: complex structure, bearing and movable seat components are required, the body is thicker, the overall shape is cumbersome.
ii. Operating principles
Floating ball valves
Close: Fluid pressure acts on the back of the ball, forcing it to seal the outlet seat.
Opening/ closing process: The ball is always in contact with the seat, causing friction and wear.
Low pressure conditions: In the case of low or no pressure, due to the weight of the ball itself, the ball may not be tightly sealed, resulting in a reduced sealing performance.
Fixed ball valve
Seal: Seal force is achieved by spring preload or fluid pressure pushing the seat without ball movement.
Opening/ closing process: The ball will be briefly separated from the seat, reducing friction and extending service life.
Pressure Adaptability: Sealing performance is relatively stable and is not affected by fluid pressure.
III. Applicable Working Conditions
Floating ball valves
Pressure range: suitable for low to medium pressure applications (e.g., ≤Class 600).
Nominal Diameter Range: usually small or medium diameter (≤NPS 8).
Fluid Requirements: Suitable for cleaning fluids to avoid particulate matter that may accelerate seal wear.
Typical application: general water supply and drainage systems, HVAC systems, etc.. Fixed ball valve
Pressure range: Suitable for high pressure (up to 2500 levels).
Nominal Diameter Range: Suitable for large diameter (NPS 60 or less).
Media Compatibility: Suitable for medium containing particles, good abrasion resistance.
Typical applications: key piping systems in petrochemical, natural gas transmission, and power industries.
Floating ball valves
Fixed ball valve
Floating ball valves
Fixed ball valve
DIB-II: consists of a piston effector and a double piston effector.