Quick answer: a ball valve isolates flow with a bored ball turned a quarter turn, which gives fast operation, tight shut-off and a straight flow path when open. Floating ball designs suit small and medium sizes; trunnion mounted designs carry the seat load on bearings and suit larger sizes and higher pressures.
Floating or trunnion mounted?
| Design | How it works | Where it fits |
|---|---|---|
| Floating ball | Line pressure pushes the ball against the downstream seat | Small and medium sizes, moderate pressure classes |
| Trunnion mounted | Ball is held by a trunnion; seats are spring loaded against it | Large sizes, higher pressure classes, pipeline service |
Bore, body and seat options
- Full bore and reduced bore
- One-piece, two-piece and three-piece body construction
- Soft seats: PTFE, RPTFE, PEEK, Devlon
- Metal seats for abrasive or high temperature service
- Fire-safe design, anti-static device and anti-blowout stem where specified
Actuation
Ball valves are the easiest valve type to automate because a quarter turn is the full travel. Lever, gear, pneumatic and electric operators can be supplied, with the mounting pad machined to a standard interface so actuators can be fitted at site or at the plant before shipment.
Where ball valves are specified
- Pipeline isolation and pigging duty
- Loading and unloading arms, truck and ship transfer
- Drain, vent and sampling points
- Metering and manifold stations
Testing and documentation
- Shell and seat tests before shipment
- Seat leakage confirmed to the agreed acceptance class
- Torque test and operator function check when actuated
- Material certificate and test record shipped with the valves
待补内容位：待补：可生产口径与压力上限、球体与阀杆材质选项、是否可做全焊接球阀与低温球阀、防火与防静电设计说明、交期。