The differences between a floater (floating) ball valve and a trunnion ball valve primarily lie in their design, operation, and suitability for specific applications. Here's a detailed comparison:
Design and Structure
Floating Ball Valve:
Features a single stem that connects to the top of the valve ball.
There is no lower support for the ball; instead, it floats within the valve body.
When the valve is closed, fluid pressure pushes the ball against the seat, creating a seal.
Trunnion Ball Valve:
Incorporates two lugs or ears (trunnions) fixed to the valve ball.
These trunnions are supported by bearings in the valve body, allowing the ball to rotate smoothly.
The ball is fixed in position by the trunnions, preventing it from moving under fluid pressure.
Operation and Performance
Floating Ball Valve:
Relies on fluid pressure to maintain the seal between the ball and the seat.
Suitable for applications with lower pressures and temperatures.
As the valve size increases, the weight of the ball can lead to increased torque and potential seat deformation.
Trunnion Ball Valve:
Provides stable sealing performance regardless of fluid pressure.
Suitable for high-pressure, high-temperature, and corrosive media applications.
The fixed position of the ball reduces torque and seat deformation, leading to longer service life.
Maintenance and Durability
Floating Ball Valve:
May require more frequent maintenance due to potential wear and tear on the seat and ball.
Seat replacement can be challenging, often requiring the valve to be removed from the pipeline.
Trunnion Ball Valve:
Offers easier maintenance due to the ability to replace components in-line without removing the valve from the pipeline.
The robust design and stable sealing performance contribute to longer service intervals and reduced downtime.
Cost and Suitability
Floating Ball Valve:
Generally less expensive than trunnion ball valves.
Suitable for smaller valve sizes and less demanding applications.
Trunnion Ball Valve:
More expensive due to the complex design and higher-quality materials required.
Suitable for larger valve sizes and harsh operating environments.
