How it works:
- Double eccentric design: stem center offset body center + offset seat center.
- Action Mechanics:
- The disc is completely disengaged from the seat when opened, reducing friction and operating torque.
- The disc gradually engages the seat when closed to avoid extrusion damage.
- Thermally compensated design: Lower stem disc springs allow thermal expansion and provide continuous grounding
The particularity of the packing design
- Deep stuffing box:
- Tetrafluoroethylene (TFE) V-shaped filler (long life).
- High temperature compression packing (applicable ≤ 750°F)
- Stainless steel fasteners as standard.
- Optional fillers:
- Live-loaded packing:
- Optional configurations for enhanced sealing and controlled fugitive emissions (API 641 certified).
- Inverted packing configuration: suitable for vacuum conditions.
The particularity of the valve seat design
| Seat type | Sealing material | Peculiarity | Pressure/temperature resistance | Certification Standards: |
| S02 | TFM polymers | Bi-directional sealing, pressure-responsive sealing lip; Chemical resistance (except alkaline solutions) | 740 psi, -46~260°C | ASME/FCI 70-2 Class VI |
| F02 | Stainless steel + TFM inserts | Fireproof design, metal-to-metal triple seal; Two-way fire certification | 1,480 psi, -46~260°C | API 607 4th Edition |
| M01 | 316 Stainless Steel (Full Metal) | ultra-high temperature applications; Washout resistance | The rated pressure of the same valve body is up to 750°C | ASME/FCI 70-2 Class IV |
The particularity of the material
- Body Material:
- Carbon steel (A216 WCC): Standard operating conditions.
- Low-temperature carbon steel (LCC, ASTM A352): -46°C low-temperature condition.
- Stainless steel (316/CF8M): corrosive media or high temperature.
- Key Component Materials:
- Stem: 17-4PH stainless steel (≤650°F) → Nickel-based alloy for high temperature (UNS 7718/5500).
- Disc: Hard chrome plated stainless steel (anti-wear).
- Bearings: Teflon+ steel (standard) or Teflon+ 316SS (high temperature)
Applicable media
- Conventional media: water, oil, steam, gas, slurry.
- Special working conditions:
- High temperature: steam, hot oil (≤750°F, M01 seat required).
- Vacuum: Absolute pressure 20 μm (S02/F02 seat).
- Sulfur Condition: Complies with NACE MR0175 (H₂S Corrosion Resistance).
- Low temperature: -46°C (LCC body).
Maximum temperature and pressure
| Parameter | Standard value | Remark |
| Maximum temperature | 750°F（399°C） | M01 seat + nickel-based alloy stem required |
| Highest pressure | Class 300 Body: 740 psi (ambient) | Seat-limited (e.g., S02 seat up to 740 psi) |
| Fire rating | F02 Seat: 1,480 psi + 30 minute fire certification | API 607 4th Edition |
Comparison table of key features
| Characteristic | S02 Valve Seat (TFM) | F02 Seat (Metal+TFM) | M01 Valve Seat (Full Metal) |
| Sealing grade | Class VI (Zero Leakage) | Class VI (Zero Leakage) | Class IV (Low Leakage) |
| Pressure resistance | 740 psi | 1,480 psi | The rated pressure of the valve body |
| Temperature resistance limit | 260°C (intermittent 500°F) | 260°C (intermittent 500°F) | 399°C（750°F） |
| Fire certification | No | API 607 bidirectional certification | No |
| Applicable media | Chemicals, vapors (≤200 psi) | High-pressure steam and fire risk working conditions | UHT steam/hot oil |
Learn More about Butterfly Valves《What is a Butterfly valve? The “Flow commander ” of industrial pipelines》
