Floating Ball Valve VS Trunnion Mounted Ball Valve: Structure, Pressure Class & Application Comparison
Floating Ball Valve VS Trunnion Mounted Ball Valve: Structure, Pressure Class & Application Comparison：
The ball has no top & bottom support trunnion, only supported by two side seats. Line pressure pushes the ball to press the downstream seat tightly when closed, only single-direction tight sealing is realized.
Less spare parts, simple casting & machining. Standard size limit: DN≤200 (NPS8) under GB/T12237-2021.
Trunnion Mounted Ball Valve
The ball is locked by upper & lower trunnion bearings, no lateral shift. Spring loaded seats on both sides clamp the ball to achieve bi-directional bubble tight sealing.
More components, complex production process. Size range covers DN15~DN600 (NPS1/2~NPS24) per GB/T12237-2021.
Pressure Class Comparison (Verified By GB/T12237-2021 & ASME B16.34)
Floating Ball Valve Working Pressure
GB PN series: PN16, PN25, PN40, PN63, PN100
ASME Class: Class150, Class300, Class600
Limitation: If DN＞200 or Class＞600, operating torque surges sharply, floating design is not recommended.
Trunnion Ball Valve Working Pressure
GB PN series: PN16 ~ PN420
ASME Class: Class150 ~ Class2500
No size & high-pressure limitation; steady low torque under all pressure grades.
Torque, Service Life & Cost
Floating Ball Valve
Torque rises along with line pressure. Seats wear fast under high pressure & large size. Fewer components, lower purchase & maintenance cost.
Fit for: Low cycle operation, clean particle-free fluid.
Trunnion Mounted Ball Valve
Trunnion bearings bear ball load, torque keeps stable. Spring seats compensate abrasion automatically for longer service life. More parts lead to higher overall cost.
Fit for: Frequent on-off, particle-laden fluid, high differential pressure pipeline.
Floating Ball Valve Working Pressure
GB PN series: PN16, PN25, PN40, PN63, PN100
ASME Class: Class150, Class300, Class600
Limitation: If DN＞200 or Class＞600, operating torque surges sharply, floating design is not recommended.
Trunnion Ball Valve Working Pressure
GB PN series: PN16 ~ PN420
ASME Class: Class150 ~ Class2500
No size & high-pressure limitation; steady low torque under all pressure grades.
Torque, Service Life & Cost
Floating Ball Valve
Torque rises along with line pressure. Seats wear fast under high pressure & large size. Fewer components, lower purchase & maintenance cost.
Fit for: Low cycle operation, clean particle-free fluid.
Trunnion Mounted Ball Valve
Trunnion bearings bear ball load, torque keeps stable. Spring seats compensate abrasion automatically for longer service life. More parts lead to higher overall cost.
Fit for: Frequent on-off, particle-laden fluid, high differential pressure pipeline.
Application Scenarios By Industry
Recommended Applications For Floating Ball Valve
Municipal water supply & small heating steam pipeline (PN16/Class150, DN50~DN150)
Small sanitary pipeline for food & pharmaceutical, particle-free clean medium
Factory compressed air, small tank inlet & outlet isolation
General industrial pipelines with tight budget, single-direction sealing acceptable
Recommended Applications For Trunnion Mounted Ball Valve
Long-distance high-pressure oil & gas transmission trunk line (Class600+, DN200+)
High temp & high pressure steam / circulating water pipeline for power & metallurgy plant
Mining & chemical pipeline carrying sediment, crystal & corrosive fluid
Process pipelines requiring bi-directional bubble tight shut-off & DBB double block bleed
Severe high-pressure service: subsea, oil well wellhead
Recommended Applications For Floating Ball Valve
Municipal water supply & small heating steam pipeline (PN16/Class150, DN50~DN150)
Small sanitary pipeline for food & pharmaceutical, particle-free clean medium
Factory compressed air, small tank inlet & outlet isolation
General industrial pipelines with tight budget, single-direction sealing acceptable
Recommended Applications For Trunnion Mounted Ball Valve
Long-distance high-pressure oil & gas transmission trunk line (Class600+, DN200+)
High temp & high pressure steam / circulating water pipeline for power & metallurgy plant
Mining & chemical pipeline carrying sediment, crystal & corrosive fluid
Process pipelines requiring bi-directional bubble tight shut-off & DBB double block bleed
Severe high-pressure service: subsea, oil well wellhead
Quick Selection Checklist
Choose floating ball valve if all conditions met
DN≤200; Pressure ≤Class600 / PN100; Clean particle-free fluid; Single seal enough; Cost sensitive project.
Choose trunnion ball valve if any condition exists
DN＞200; Pressure＞Class600; Particle contained medium; Bi-directional sealing required; Frequent operation; High differential pressure long pipeline.
Choose floating ball valve if all conditions met
DN≤200; Pressure ≤Class600 / PN100; Clean particle-free fluid; Single seal enough; Cost sensitive project.
Choose trunnion ball valve if any condition exists
DN＞200; Pressure＞Class600; Particle contained medium; Bi-directional sealing required; Frequent operation; High differential pressure long pipeline.