I. Definition & Working Principle
A silent check valve is an advanced type of check valve designed with:
Spring-assisted closure or hydraulic damping
Soft-sealing materials (e.g., rubber, polyurethane)
Operation Phases:
Forward Flow:
Disc opens smoothly with minimal resistance (ΔP ≤ 0.03 MPa).
Pre-Close Stage:
Spring/hydraulic system initiates slow closure to prevent water hammer.
Final Seal:
Noise reduced to ≤20 dB (vs. 50-70 dB for traditional valves).
II. Applications & Advantages
Key Uses:
High-rise water supply (prevents backflow-induced pipe vibration).
HVAC systems (protects compressors from refrigerant reverse flow).
Corrosive industrial pipelines (low-noise requirement).
Comparative Advantages:
| Feature | Silent Check Valve | Standard Swing Check Valve |
|---|---|---|
| Noise Level | ≤20 dB | 50-70 dB |
| Water Hammer Effect | Eliminated | Significant |
| Lifespan | 10+ years (GB/T 13932) | 5-8 years |
III. Selection Criteria
Pressure Rating: Match pipeline design (e.g., PN10, PN16 per GB/T 12235).
Sizing: Example: DN50 valve at 2 m/s flow rate ≈ 12 m³/h.
Material:
Corrosive media: Fluorine-lined (PTFE coating).
High-temperature steam: Stainless steel (304/316L).
IV. Maintenance & Troubleshooting
Inspection: Seal wear check every 2 years.
Common Issues:
Disc sticking: Caused by debris; clean pipeline or install a filter.