III. Feature Description

A. Three-Eccentric Structure: Solving Traditional Butterfly Valve Limitations

• When closing, the disc rotates and only contacts the seal face at the final 5°~10° of rotation, minimizing friction and wear.
• The conical seal face’s eccentricity ensures uniform pressure distribution across the seal, enhancing sealing reliability even with minor pipeline misalignment.

  For DN400 large-diameter applications, this design extends seal life by 2~3 times compared to double-eccentric butterfly valves, reducing maintenance frequency.

B. Metal Sealing: Adapt to High-Temperature & Abrasive Conditions

C. Pneumatic Actuation: Efficient Automation & Safety

• Double-acting actuators provide consistent torque (≥2000 N·m for DN400, PN10) to overcome large-diameter disc inertia, ensuring smooth opening/closing even under low air supply pressure (0.4MPa).
• Spring-return actuators offer fail-safe protection: In case of air pressure loss (e.g., compressor failure), the spring forces the valve to close (or open, per design) to isolate media—essential for safety-critical systems like chemical process lines or municipal water main isolation.

  Optional electro-pneumatic positioners allow precise flow modulation (e.g., adjusting cooling water flow to match power plant load), improving process efficiency.

D. Large-Diameter Design: High Flow Efficiency & Structural Stability

IV. Manufacturing Processes

A. Material Preparation & Quality Verification

• WCB Valve Body: Raw WCB billets undergo spectral analysis to confirm chemical composition (C: 0.25%~0.35%, Mn: 0.60%~1.00%) and ultrasonic testing (UT) to detect internal porosity or cracks. Casting is done via sand casting with resin-bonded sand, followed by normalization heat treatment (890~950℃, air cooling) to refine grain structure and relieve stresses.
• 304/316L Disc: Stainless steel plates are cut via laser (tolerance ±0.5mm) and forged to enhance density. Forged blanks undergo solution annealing (1050~1100℃ for 304, 1020~1080℃ for 316L) to restore corrosion resistance, then machined to final dimensions.

B. Precision Machining of Three-Eccentric Structure

• Eccentricity Machining: The disc’s three eccentricities are processed via 5-axis CNC milling centers, with dimensional tolerance controlled within ±0.03mm. A coordinate measuring machine (CMM) verifies eccentricity values after machining to ensure compliance with design standards.
• Seal Face Surfacing & Lapping: The disc and valve body’s seal faces are welded with Stellite 6 (via TIG welding) or sprayed with WC (high-velocity oxygen fuel, HVOF) to a thickness of 1.5~2.0mm. The seal faces are then lapped to a surface roughness of Ra ≤0.4μm using diamond abrasive, ensuring uniform contact during sealing.
• Shaft & Bearing Assembly: The valve shaft (304 stainless steel) is precision-ground to a diameter tolerance of h7 (±0.015mm) and assembled with self-lubricating bearings (bronze with PTFE inserts) to reduce rotational friction. The shaft’s axial and radial runout is tested to ≤0.05mm to avoid disc deflection.

C. Pneumatic Actuator Integration & Calibration

• Actuator Mounting: The actuator is mounted to the valve via an ISO 5211 adapter flange, with the drive shaft connected to the valve shaft via a spline coupling. Alignment is checked using a laser alignment tool to ensure 90° rotation without torque deviation.
• Torque Calibration: The actuator’s torque output is calibrated to match the valve’s required torque (≥2000 N·m for DN400, PN10). Flow control valves are adjusted to set opening/closing time (15~30 seconds), and the spring-return actuator’s spring force is tested to ensure fail-safe operation within 5 seconds of air loss.

D. Quality Testing & Certification

• Hydrostatic Shell Test: The valve body is filled with water and pressurized to 1.5MPa (1.5×PN10) for 30 minutes, with no visible leakage or deformation.
• Seal Leak Test: Under 1.1MPa (1.1×PN10) air pressure, the closed valve’s leakage is measured via a flow meter—ANSI/FCI Class IV compliance (≤0.01% of rated flow) is confirmed.
• Actuation Cycle Test: The valve undergoes 1000 open-close cycles with pneumatic actuation, checking for smooth operation, torque stability, and seal integrity after cycling.
• Material Certification: Each valve is accompanied by material test reports (MTRs) for WCB, 304/316L, and Stellite 6, ensuring compliance with ASTM/ASME standards.