Description

Cryogenic Floating Ball Valve Technical Data Sheet (Cast Stainless Steel)

1. Product Overview

Product Type: Cryogenic Floating Ball Valve
Body Material: Cast Stainless Steel (ASTM A351 CF8/CF8M/CF3M)
Operation: Manual (Lever / Gear Operated)
Connection Type: Flanged Ends (RF / RTJ)
Design Standard: BS 6364, API 6D, ASME B16.34, ISO 28921-1
Temperature Range: -196°C ~ +120°C (Cryogenic service)
Nominal Size: NPS 1/2″ ~ 10″ (DN15 ~ DN250)
Pressure Class: Class 150 ~ Class 600 (PN16 ~ PN100)
End Flanges: ASME B16.5 (RF / RTJ)
Face-to-Face Dimensions: ASME B16.10, API 6D
Testing Standard: BS 6364 (Cryogenic testing), API 598, ISO 28921-1

2. Applicable Standards & Specifications

3. Main Technical Parameters

4. Material of Construction (Cast Stainless Steel)

4.1 Standard Material Combinations for Cryogenic Service (-196°C)

4.2 Critical Design Features for Cryogenic Service

5. Structural Features & Working Principle

• Floating Ball Design: The ball is not fixed but floats between two seats. Upstream pressure pushes the ball against the downstream seat, ensuring tight shut-off. Suitable for smaller diameters (up to NPS 10) .

• Cryogenic-Ready Extended Bonnet: The extended bonnet (stem extension) ensures that the stem packing and operating mechanism remain at near-ambient temperature, preventing freeze-up and allowing smooth operation .

• Two-Piece / Three-Piece Cast Body: Cast stainless steel body (ASTM A351 CF8/CF8M) provides excellent low-temperature toughness and corrosion resistance. Split body design allows for easy maintenance .

• Low Emission Packing: Special cryogenic packing with live-loading (Belleville springs) maintains consistent seal stress despite thermal cycling .

• Relief Hole in Ball: Upstream pressure relief hole prevents cavity pressure build-up when valve is closed, protecting against over-pressurization from liquid vaporization .

• Lubrication: Cryogenic-compatible lubricants ensure low operating torque at extreme temperatures .

• Surface Finish: Ball and seat sealing surfaces are super-finished (Ra ≤ 0.4μm) to minimize leakage and reduce operating torque .

6. Seat Material Selection Guide for Cryogenic Service

7. Dimensional Data (Reference – Class 150/300 RF Flanged)

Note: Dimensions are for reference only. Final dimensions vary by manufacturer and specific pressure rating. Consult GA drawing for final approval.

7.1 Face-to-Face Dimensions (L) – ASME B16.10 / API 6D

7.2 Overall Dimensions (Approximate) – Class 150/300

*Note: Stem extension length (E) is critical for cryogenic service to maintain packing temperature above -50°C and prevent ice formation .*

8. Cryogenic Testing Requirements (Per BS 6364 / ISO 28921-1)

9. Installation, Operation & Maintenance Instructions

1. Pre-Installation Inspection:

   • Remove protective covers. Clean valve interior to remove debris .

   • Verify valve has undergone cryogenic testing and treatment.

   • Inspect flange faces and RTJ grooves for damage.

2. Installation:

   • Ensure pipeline is clean and dry, free from moisture and contaminants.

   • Install valve with flow direction matching application requirements (bidirectional capability standard) .

   • Use appropriate gaskets (spiral wound for RF, ring joint for RTJ flanges).

   • Ensure stem extension is adequately insulated to prevent ice formation and cold loss .

   • Support piping adequately to avoid stress on valve flanges.

   • Tighten flange bolts evenly in crisscross pattern to recommended torque.

3. Operation:

   • Rotate lever/gear clockwise to close, counter-clockwise to open.

   • Do not use pipe extensions or hammers on lever for additional leverage.

   • For gear-operated valves, ensure gearbox is lubricated with low-temperature grease.

   • During cooldown, operate valve slowly to prevent thermal shock.

4. Maintenance:

   • Regular inspection of stem packing for leakage; adjust gland nuts evenly if slight leakage occurs.

   • Check extended bonnet for ice accumulation; ensure insulation is intact.

   • For major repairs, allow valve to warm to ambient temperature before disassembly.

   • Replacement parts must be OEM-sourced and cryogenically treated to maintain performance.

   • Re-lubricate stem threads periodically with cryogenic-compatible lubricant.

10. Ordering Information

When ordering Cryogenic Floating Ball Valves, please specify:

1. Valve model / type

2. Nominal size (NPS / DN)

3. Pressure class (Class)

4. Body material (ASTM A351 CF8/CF8M/CF3M)

5. Seat material (PTFE/RTFE/TFM/PEEK/Metal)

6. Connection type (RF/RTJ flanged)

7. Stem extension length (if special required)

8. Operation type (Lever / Gear)

9. Applicable medium and operating temperature

10. Special requirements (Cryogenic test certificate, NACE, fire-safe, low emission packing, etc.)

11. Quantity required

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Note: This technical data sheet is a general guideline for Cast Stainless Steel Cryogenic Floating Ball Valves designed per BS 6364 and API 6D standards. For specific project requirements, including detailed material selection, pressure class, and dimensions, please refer to the approved manufacturer’s drawing and purchase order. Specifications are subject to change without notice.