What are the characteristics of a swing check valve?

Swing check valves (Swing Check Valves) are critical valve devices that rely on the fluid's own flow to achieve automatic opening and closing. Their unique working principle and structural design make them indispensable in industrial pipeline systems. The following elaborates on their technical characteristics from multiple dimensions:

1. Structural Design Features

(1) Rotating Mechanism Design

The valve adopts a single-disc hinged structure, where the disc is connected to the valve body via a precision pin shaft, allowing free rotation of 60–90 degrees. This design offers the following advantages:

• Off-center disc design, utilizing gravity torque for rapid closure

• Hardened pin shaft (e.g., nitrided surface) with a wear-resistant lifespan exceeding 100,000 cycles

• Balanced counterweights for large valves (DN ≥ 300) to ensure reliable closure

(2) Sealing System Configuration

Multiple sealing solutions are available based on working conditions:

• Standard type: Metal hard seal (seat overlay welded with Stellite 6 alloy)

• High-sealing type: Metal seal + elastomer secondary seal

• Special type: Full PTFE-lined seal (resistant to highly corrosive media)

2. Fluid Performance Characteristics

(1) Excellent Flow Characteristics

• Low flow resistance coefficient (ξ = 0.8–1.5), only 1/3 that of lift check valves

• Full-bore design, with a Kv value 15–20% higher than similar products

• Strong media adaptability, capable of handling fluids with solid particles (≤15% concentration)

(2) Dynamic Response Characteristics

• Low opening pressure differential (0.02–0.05 MPa)

• Fast closing response time (≤0.3 sec)

• Equipped with damping devices for slow closure (3–5 sec), effectively suppressing water hammer

3. Engineering Application Features

(1) Installation Flexibility

• Supports horizontal, vertical (upward flow), and inclined installation

• Flange standards compliant with ANSI, DIN, JIS, and other systems

• Customizable extended valve bodies for special pipe diameter requirements

(2) Easy Maintenance

• Online maintenance design, eliminating the need for pipeline disassembly

• Modular structure, allowing quick replacement of key components

• Wear indicator device for predictive maintenance

4. Solutions for Special Working Conditions

(1) High-Temperature & High-Pressure Applications

• Chromium-molybdenum steel body + Inconel disc

• High-temperature graphite sealing system (withstands up to 650°C)

• Reinforced hinge mechanism, pressure rating up to Class 2500

(2) Corrosive Media

• Full lining structure (PTFE/PFA)

• Hastelloy C276 material option

• Cathodic protection interface reserved

5. New Technological Trends

(1) Intelligent Upgrades

• Equipped with position sensors for real-time monitoring of valve status

• Integrated pressure monitoring module for smart maintenance prediction

• Self-lubricating bearings to extend maintenance-free periods

(2) Energy Efficiency Optimization

• Low-torque bearing design, reducing flow resistance

• Streamlined disc profile optimization, minimizing turbulence losses

• Lightweight design (15–20% weight reduction compared to traditional structures)

Key Considerations for Selection

When selecting swing check valves for engineering applications, the following parameters must be prioritized:

• Media properties (viscosity, corrosiveness, solid content)

• Operating pressure differential and flow velocity range

• Permissible pressure fluctuation range

• Water hammer protection level requirements

• Ambient temperature conditions

Quality Standards & Testing

High-quality swing check valves should comply with international standards such as API 594 and ISO 5208, and undergo rigorous performance tests before delivery, including:

• 200% working pressure shell test

• Sealing performance test (leakage rate ≤ 0.1%)

• Fatigue life test (≥50,000 open-close cycles)

• Material composition and mechanical property inspections

Conclusion

With advancements in materials science and fluid dynamics, modern swing check valves are evolving toward higher reliability, longer service life, and smarter functionality, providing superior fluid control solutions for various industrial systems.