Trunnion
model A11, A41, A61
The trunnion mounted ball valve is Valland’s most widely supplied valve type. In this design the ball is supported by trunnions (or by support plates on small sizes below 4"), so the seats — floating, self-relieving or double piston effect — are pushed against the ball by line pressure and springs. This makes the trunnion design suitable for high pressure classes and large sizes, where a floating ball would generate excessive seat loads.
Models A11 (standard side entry), A41 (double block and bleed) and A61 (subsea) share the same engineering platform. Typical applications include pipeline isolation, launcher/receiver stations, manifolds, wellhead flowlines under API 6A, and subsea systems under API 6DSS. Seats are available in soft sealing or metal-to-metal execution with tungsten carbide coating for abrasive or erosive media; SIL certification up to SIL 3 is available.
Field references include trunnion mounted ball valves in duplex F51 for the AkerBP Hod field development, a fast-track NPS 30 valve delivered in 9 weeks for ConocoPhillips Skandinavia (EKOJ project), and subsea trunnion ball valves with direct ROV operation for the Hindustan Oil Exploration B-80 field (India).
| Applicable standards | API 6D, API 6DSS or API 6A Design according to ASME B16.34 or ASME VIII Div. 1 & 2 |
| Pressure Class Range | ANSI Class 150 lbs. to 4500 lbs. API6A Class 3000 PSI to 15000 PSI |
| Size Range | API 6D - from 1/2" to 42" API 6A - from 1.13/16" to 13.5/8" |
| Ends design | Flanged (RF/RTJ) - ASME B16.5 or ASME B16.47 Flanged (6B/6BX) - API 6A Compact (Norsok Standard L-005) Butt-Weld (ASME B16.25) and/or Butt-Weld + Pipe Hubbed according to client Clamp |
| Body Design | Two or Three Pieces |
| Closure Design | Bolted Closure or Fully welded |
| Ball support | Trunnion (small sizes < 4") - Support Plates |
| Seat design | Floating Self-Relieving - Floating Double Piston Effect Soft Sealing - Metal to Metal (Tungsten Carbide Coating) |
| Valve operation | Manual: Lever or Gearbox Actuated: Pneumatic / Hydraulic / Electric / Electro-Hydraulic |
| Available Materials | CS, LTCS, SS, Duplex SS, Super Duplex SS, 6Mo, Inconel, Incoloy, Hastelloy, Monel, Titanium NACE MR0175 according to client request. |
| Additional Features | Double Block and Bleed, Anti Blowout Stem, Antistatic Device, special execution for subsea applications |
| Testing and Certification | Testing: Hydrostatic, High Pressure Gas, Pneumatic and Functional API 598 - API 6A PSL3G, API 6A PR2 & Endurance Fire testing: API 6FA, API 607, BS 6755 part 2 Fugitive Emission Test: ISO 15848 - 1 & 2 SIL Certificate up to SIL 3 PED 2014/68/UE Mod.H |
