API 609 Triple Offset Butterfly Valve
Description
TRIPLE ECCENTRIC BUTTERFLY VALVE TECHNICAL DATA SHEET
Design Type: Triple Offset Metal-Seated | Operation: Pneumatic/ Electric/ Gear/ Manual
1. BASIC PARAMETERS
| Parameter | Specification Range |
|---|---|
| Size (NPS/DN) | 2″ to 80″ (DN 50 to DN 2000, custom up to DN 2400) |
| Pressure Rating | Class 150-400 (PN 6-40) |
| Temperature Range | -40°C to 650°C (SS); -29°C to 425°C (CS) |
| Leakage Class | ≤0.1×DN mm³/s (ISO 5208) / Zero Leakage (API 598) |
| Flow Coefficient (Cv) | 95–38,000 (DN 800 = Cv 38,000) |
2. DESIGN & PERFORMANCE
Key Features
-
Triple Offset Geometry:
• 1st Offset: Shaft behind seal plane
• 2nd Offset: Shaft axis offset from pipe centerline
• 3rd Offset: Conical seat angle → Zero friction during operation -
Multi-Layer Metal Seal: Stellite-coated disc + Flexible graphite/SS ring seat (Fire-safe per API 607)
-
Bidirectional Sealing: Equal sealing performance in both flow directions
-
Low Torque Design: 30% lower operating torque vs. double-eccentric valves
Pressure Testing
| Rating | Shell Test (MPa) | Seat Test (MPa) |
|---|---|---|
| Class 150 | 3.0 | 2.2 |
| Class 300 | 7.5 | 5.5 |
| Class 600 | 15.0 | 11.0 |
| Standards: API 598, ISO 5208 |
3. MATERIAL SPECIFICATION
| Component | Material Options |
|---|---|
| Body | WCB (A216), CF8/CF8M (A351), LCC (A352), F51/F53 (A995), WC6 (A217) |
| Disc | Body material + Stellite 6 overlay (HRC 45-50) |
| Stem | 17-4PH (A564), F6a (A182), 316Ti (EN 1.4571) |
| Seat Assembly | 316L + Flexible graphite (Standard); Inconel 625 (Corrosive service) |
| Packing | Reinforced graphite (-196°C~650°C) / PTFE (-40°C~200°C) |
4. STANDARDS & CERTIFICATIONS
| Category | Standards |
|---|---|
| Design & Manufacture | API 609, ISO 10631, ASME B16.34 |
| End Connections | ASME B16.5 (Flanged), ASME B16.25 (Butt Weld), ISO 5211 (Actuator Mounting) |
| Face-to-Face | ASME B16.10, ISO 5752 |
| Certifications | NACE MR0175/MR0103 (SSC), ISO 15848-1 (TA-LU) Fugitive Emissions, PED 2014/68/EU |
5. ACTUATION OPTIONS
| Type | Control Method | Performance |
|---|---|---|
| Pneumatic | Rack & pinion / Scotch yoke (0.4-0.8 MPa) | Fail-safe close/open (≤3s actuation time) |
| Electric | 4-20mA modulating (AC/DC power) | Positioning accuracy: ±0.5% |
| Manual Gear | Worm gearbox (≤20:1 reduction ratio) | With torque limiter |
6. TYPICAL APPLICATIONS
-
Severe Service:
► High-temperature steam lines (≤650°C)
► Sulfuric acid / Caustic soda transfer (PTFE-lined option)
► LNG cryogenic service (-196°C, extended bonnet) -
Industries:
• Power generation (FGD systems)
• Offshore oil & gas (NACE compliant)
• Chemical processing (CRA materials)
• Pulp & paper (abrasion-resistant seats)
7. OPTIONAL FEATURES
-
Enhanced Sealing: Fire-safe design (API 607/ISO 10497), Cryogenic extension stem
-
Smart Functions:
• IoT-enabled position monitoring (4-20mA/HART)
• Partial stroke testing (PST) capability -
Special Designs:
▶ Vacuum service (10⁻⁶ mbar)
▶ Erosion-resistant coatings (WC-Co overlay)
▶ Sanitary finish (Ra ≤ 0.8 μm, 3-A compliant)
SELECTION NOTES:
For temperatures >425°C: Use Cr-Mo steel body (A217 WC6/WC9) + Stellite 6 disc overlay.
H₂S services: Specify NACE MR0103 materials with hardness ≤22 HRC.
High-cycle applications (≥100,000 cycles): Upgrade to Inconel 718 stem.
