PN16 Wafer Type Metal Seated Check Valve Stainless Steel 304 316 Manual Check Valve

III. Structural Design & Technical Features

1. Butterfly Check Mechanism
   • Disc rotates around a horizontal pin with streamlined flow path, pressure drop 30% lower than lift checks (DN100 loss ≤0.08MPa).
   • Single/double-disc design: Double discs for large sizes disperse medium impact, preventing water hammer.
2. Metal Seal Optimization
   • Disc-seat conical fit (3°-5° angle) self-tightens via medium pressure, specific pressure ≥20MPa.
   • Seal surfaces precision-lapped by 5-axis grinder to flatness ≤0.01mm, red lead test contact rate ≥90%.
3. Extreme Condition Adaptability
   • Cryogenic design: Long-neck pin prevents freezing at -196℃, disc reset time ≤0.5s.
   • High-temperature: 316 SS solution-treated for 50% better oxidation resistance at 600℃ vs. 304.

IV. Manufacturing Processes & Quality Control

1. Precision Casting Flow
   • Investment casting process, blank tolerance ≤±0.3mm, 100% ultrasonic testing (UT) for internal defects.
   • SS parts solution-treated at 1050℃, grain size ≥Grade 5, passing ASTM A262 E-method intergranular corrosion test.
2. Surface Treatment Technology
   • Seal surfaces plasma-overlaid with STL alloy (≥1.5mm thickness, HRC58-62), erosion life >8 years.
   • Body electropolished (Ra≤0.4μm), passivated for salt spray test ≥1000 hours.
3. 3D Quality Inspection
   • Hydrostatic test: 1.5x pressure (30min hold), 1.1x sealing pressure—zero leakage.
   • Spectral analysis: Element deviation ≤0.03% per heat, traceable to heat number.
   • SIL certification: Meets IEC 61508, achieves SIL 2 functional safety.