Case
Case
Prevent Media Backflow: Automatically closes when reverse flow occurs due to pressure changes or pump shutdown, protecting upstream equipment.
Ensure Equipment Safety: Installed at pump outlets to prevent water hammer-induced damage; used in boiler feed systems to block high-temperature water backflow.
Maintain System Pressure: Stabilizes pipeline pressure by preventing reverse flow-induced fluctuations.
Avoid Contamination: Prevents mixing of different media or contamination in chemical, water supply, or wastewater systems.
Mitigate Water Hammer: Rapid closure (or delayed-action design) reduces pressure surges caused by sudden flow stoppage.
* Pump outlets
* Water supply systems
* Industrial pipelines
* Drainage/sewage systems
* Compressed air systems
Check valves use simple mechanical structures to control unidirectional flow, ensuring safe and efficient pipeline operation. Proper selection and installation enhance system reliability and reduce maintenance costs.
| Type | Applicable Scenarios | Installation Orientation | Advantages | Disadvantages | Key Selection Criteria |
| Swing Check Valve | Medium/high pressure, large flow, horizontal pipelines | Horizontal/vertical (verify) | High pressure resistance, low pressure loss, long lifespan | High closing impact, requires space | Valve disc material (cast iron/stainless steel), sealing surface hardness, water hammer control |
| Rubber Flap Check Valve | Wastewater with particles/fibers, low-pressure systems | Horizontal preferred | Excellent sealing, corrosion resistance, anti-clogging | Not suitable for high temp/pressure, rubber aging | Rubber material (NBR/EPDM), medium corrosivity, operating temperature |
| Dual Plate Check Valve | Medium/low pressure, space-limited areas | Any direction | Compact, fast response, low pressure loss | Weak sealing, unsuitable for high-viscosity media | Plate material (stainless steel/alloy), flow velocity, allowable pressure loss |
| Single Plate Check Valve | Clean water, low-pressure, low-speed systems | Horizontal preferred | Simple structure, low cost | Moderate sealing, vulnerable to water hammer | Plate thickness, spring strength, medium cleanliness |
| Silent Check Valve | Noise-sensitive scenarios (building water supply) | Horizontal/vertical | Zero leakage, noiseless operation | High cost, precise installation required | Spring stiffness, flow guide design, pressure fluctuation range |
| Butterfly Check Valve | Low-pressure, large-diameter pipelines | Horizontal/vertical | Compact, lightweight, fast operation | Weak sealing, unsuitable for high pressure | Disc eccentric angle, seal ring material (PTFE/rubber) |
| Weighted Check Valve | Large-diameter pump outlets, backflow prevention | Horizontal | Rapid closure, reliable backflow prevention | Bulky, requires counterweight adjustment | Counterweight torque calculation, valve size, system inertia |
| Ball Check Valve | High-viscosity media (oil, slurry) | Vertical preferred | Wear-resistant, anti-clogging, low resistance | Poor sealing, unsuitable for high-speed flow | Ball material (rubber-coated/stainless steel), viscosity range |
Structure: Hinged disc + metal seat
Working Principle: Medium flow opens the disc; reverse flow closes via gravity + pressure difference.
Case Study: Used in a 10MPa steam pipeline at a refinery, leak-free for 5 years.
Design: Fully rubber-coated flap + shaftless structure
Performance: Handles solids ≤80% pipe diameter; 8-year lifespan in sandy wastewater (5kg/m³).
Mechanism: Dual discs + pre-tensioned spring
Water Hammer Control: Closes in ≤0.5 seconds; reduces pressure fluctuations.
Structure: Single inclined plate + guide rod
Maintenance: Seal replacement takes 30 minutes.
Selection pitfalls: not suitable for fiber-containing media (easy to get stuck)
Noise reduction principle: hydraulic buffer device + deflector design
Measured comparison: closing noise ≤45dB (ordinary valve ≥75dB)
Medical application: A tertiary hospital ICU oxygen supply system uses a silent valve to eliminate pulsation interference
Design: Concentric disc rotation; 100% open flow path.
Case Study: DN800 natural gas pipeline achieved 60% pressure drop reduction.
Design: Adjustable counterweight system; seals reliably at 45° tilt.
Self-Cleaning: Rotating ball prevents scaling; used in pulp pump outlets.
Structural Features: Swing flap with strainer + Flanged valve body
Core Components:
Tapered valve seat (Cast iron/Stainless steel construction)
360° annular strainer (Aperture ≤3mm)
Rubber sealing gasket (NBR/EPDM options)
Working Principle:
Startup Phase: Pump-generated negative pressure suction lifts the flap, allowing medium entry into pipeline
Operation State: Continuous flow maintains maximum flap opening (70-85° opening angle)
Shutdown Protection: Triple sealing achieved by flap self-weight + medium backflow pressure
Selection Warnings:
Mandatory sediment suction basket installation (Prevent silt abrasion on sealing surfaces)
Minimum submergence depth ≥3×pipe diameter (Avoid vortex-induced air entrainment)
Monel alloy body required for seawater applications (Chloride ion corrosion resistan
Clean water/steam → Swing/Silent valves
Wastewater with solids → Rubber Flap/Ball valves
High-viscosity fluids → Ball/Weighted valves
Pressure >10MPa → Swing Check Valve
Temperature >300°C → Weighted Check Valve
Limited space → Dual Plate/Butterfly valves
Budget constraints → Single Plate Valve (40% cost reduction)
Long-term use → Dual Plate Valve (3x longer maintenance cycles)
Medium Properties: Corrosivity, viscosity, solids content.
Pressure Rating: Swing valves for high pressure; Dual Plate/Butterfly for low pressure.
Flow Velocity: Low-resistance valves (Swing/Ball) for high speed; spring-assisted closure (Silent) for low speed.
Installation Space: Compact designs (Dual Plate/Butterfly) for tight spaces.
Water Hammer Risk: Use buffered (Silent) or delayed-action valves.
Maintenance: Rubber parts require periodic replacement (e.g., Rubber Flap); stainless steel offers durability.
Pump outlet: Weighted (large diameter), Swing (high pressure), Silent (low noise).
Wastewater: Rubber Flap (anti-clogging), Ball (high-viscosity slurry).
Building water systems: Silent (noise control), Dual Plate (compact).
Chemical pipelines: Swing (corrosion-resistant), Dual Plate (low-pressure clean media).
Final selection should consider specific parameters (pressure, temperature, medium, flow rate) and consultation with manufacturers.
