Cryogenic Top Entry Trunnion-mounted Ball Valves

Description

TECHNICAL DATA SHEET: TOP ENTRY TRUNNION-MOUNTED (FIXED BALL) CRYOGENIC BALL VALVE

1. Valve Identification:

Type: Top Entry, Full Port (FP) / Reduced Port (RP), Trunnion-Mounted (Fixed Ball) Design
Operation: Gear Operated / Extended Stem with Actuator (Pneumatic, Electric, Hydraulic)
Design Standard: BS 6364 / ISO 28921-1 / MSS SP-134 / API 6D (Annex F – Cryogenic)
Face-to-Face: ASME B16.10 / ISO 5752 Series 11 (Cryogenic Extended) / BS 6364 Table 1
End Connection: Flanged (RF, RTJ) ASME B16.5 / ASME B16.47 / EN 1092-1 / ISO 7005 / BW (ASME B16.25)
Body Construction: Top Entry (Single Piece Body with Removable Bonnet/Cover)

2. Design Parameters & Service:

Size Range: DN 50 (2″) to DN 600 (24″) [Typical for fixed ball, specify range]
Pressure Class: ASME: 150, 300, 600, 900, 1500 | PN: 10, 16, 25, 40, 63, 100 [Specify]
Temperature Range:
- Standard Design: -196°C (-320°F) [Liquid Nitrogen]
- Extended Design: Down to -254°C (-425°F) [Liquid Hydrogen]
- Upper Limit: +80°C (+176°F) (Dependent on seals)
Design Pressure: Per ASME B16.34 at minimum design temperature (incl. low-temp derating).
Service: LNG, LIN, LAR, LOX, LHe, LCO₂, Ethylene, High-Pressure Cryogenic Gases.

3. Body & Bonnet (Cover):

Material: A351 CF8M (316) / CF3M (316L) – Standard. A350 LF2 (clad) / Nickel Alloys (LOX/Corrosive).
Cryogenic Treatment: All pressure parts thermally stabilized per BS 6364.
Extended Bonnet: Mandatory. Length per BS 6364 Table 1 or custom. Includes drip plate.

4. Ball & Trunnions:

Ball Material: AISI 316/316L (Std), 17-4PH (H1150M) (HP), Inconel 718/625 (Corr/LOX).
Trunnion Material: Matches ball or higher strength (17-4PH, Inconel). Mechanically secured to body.
Surface Finish: Ra ≤ 0.4 µm (16 µin) on sealing surfaces.
Design: Fixed to trunnions. Zero shaft load, minimal friction, high-pressure stability.

5. Seats & Sealing System:

Type: Spring + Line Pressure Energized (Piston Effect), Dual-Sealing.
Seat Material:
- Primary: Reinforced PTFE (RPTFE) / PCTFE (Kel-F) (Std, Cryo-Tight).
- Fire-Safe Option: Graphite/Metal seats with RPTFE primary seal (*API 607/6FA*).
Design:
- Bidirectional Sealing. Line pressure forces seats against ball.
- Cavity Relief: Automatic pressure relief through seats upon opening.
- Spring Preload: Maintains seal at zero/low pressure.

6. Stem:

Material: A182 F316/F316L (Std), 17-4PH (H1150M) (HP), Monel K500/Inconel 718 (LOX/Corr).
Design: Floating Stem (decoupled from seat load), Blowout-Proof, Anti-Static per BS 6364.
Stem Seals:
- Primary Seal (Cryo Zone): Low-temp PTFE chevrons/graphite foil.
- Secondary Seal (Ambient): Live-loaded graphite packing. Fire-safe design.

7. Bearings & Thrust Control:

Trunnion Bearings: Self-lubricating, cryogenic-compatible (Rulon® AR, Turcon®).
Thrust Washers: PTFE composites on ball/seat interface.
Function: Absorb line thrust, minimize operating torque, prevent galling.

8. Sealing & Leakage:

Seat Leakage: Class VI (Bubble-Tight) per ISO 5208/API 598 (Tested cryogenically).
Stem Leakage: ISO 15848-1 Class B or better (Ambient & Cryo).
Fire Safe: API 607/6FA / ISO 10497 (Optional).
Anti-Static: BS 6364 / ISO 28921-1 compliant.

9. Operation:

Operating Torque: Consistently low (even at high ΔP). [Specify max torque at cryo temp].
Rotation: 90° quarter-turn. Open: CCW (Standard).
Actuation: Gearbox recommended. Pneumatic/Electric with extended kit.

10. Cryogenic Testing (Per BS 6364 / ISO 28921-1):

11. Features & Advantages (vs. Floating Ball):

12. Applications:

13. Optional Features:

14. Certifications & Compliance:

Key Distinctions from Floating Ball Design:

Mechanical Support: Ball is rigidly held by trunnions (not floating on stem).
Seat Load: Line pressure energizes seats → sealing improves with pressure.
Torque: Significantly lower and stable across pressure ranges.
Pressure Rating: Suitable for ASME 1500+ classes.
Cavity Management: Automatic pressure relief without external ports.
Stem Function: Pure rotational force only (no axial thrust).