NVS Swing Check Valve (Horizontal)

NVS Swing Check Valve - (Horizontal)

A swing check valve consists of a disc that swings on a hinge and shaft.
The disc swings open to allow forward flow, and when the flow stops, the disc returns to the seat to prevent backflow.
The weight of the disc and the return flow affect the closing characteristics of the valve.

A swing check valve is a type of check valve (non-return valve) used especially in water and liquid systems to prevent backflow. Its Turkish name ("çalparlı") comes from the slamming sound the valve makes when it closes suddenly.

What Is a Swing Check Valve?

• Function: Ensures one-way flow of liquid or gas and prevents reverse flow.
• Operating Principle: It closes automatically when pressure drops or the flow reverses. At the moment of closing, it makes a slamming sound due to the impact.
• Applications:
• Water mains,
• Booster pump systems,
• Pump discharge lines,
• Industrial liquid transfer systems.

Swing Check Valve vs. Standard Check Valve

Advantages and Disadvantages

✔ Advantages:

• Simple and durable design,
• Low cost,
• Effective in high-pressure systems.

✖ Disadvantages:

• Risk of water hammer (sudden closing can damage pipes),
• Noisy operation,
• Shorter service life than spring-loaded check valves.

What to Consider When Choosing a Swing Check Valve

1. Pressure Rating: Must suit the system pressure (such as PN10, PN16).
2. Material: Brass, cast iron or stainless steel options are available.
3. Connection Type: Flanged, threaded or welded connections.
4. Silent Alternatives: If there is a risk of water hammer, a spring-loaded check valve may be preferred.

Maintenance and Failure Symptoms

• Leakage: Gasket wear or a crack in the valve body.
• Reverse Flow: Faulty closing mechanism (fouling or mechanical damage).
• Excessive Noise: Blockage in the valve or an excessive pressure surge.

Recommendation: In systems with a high risk of water hammer (apartment booster pumps, large pumping stations), using a spring-loaded check valve is safer.