Swing check valve

Swing check valves are a common type of valve, primarily used in piping systems to prevent backflow of media. Their working principle is based on the automatic opening and closing of the valve disc under the influence of media flow. When the media flows forward, the valve disc is pushed open, allowing the media to pass through; when the media stops or flows in the reverse direction, the valve disc automatically closes under the action of gravity or reverse pressure, thus preventing backflow. This type of valve is simple and reliable in design and suitable for a variety of industrial applications.

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Swing check valves Technical parameters

Working Principle

The core of a swing check valve is the rotational movement of the valve disc:

• In forward flow: The medium pressure pushes the valve disc to rotate around its axis, opening the valve and allowing fluid to pass through.
• In reverse flow or when flow stops: The valve disc quickly closes under its own weight, spring force, or the reverse flow pressure of the medium, preventing backflow.
• Closing Characteristics: The valve disc has a short stroke and closes quickly, effectively reducing water hammer. However, large-diameter valves may experience impact due to inertia.

Structural Features

Core Components:

Valve Body: Provides the fluid passage; streamlined design reduces resistance.

Valve Disc: Circular or disc-shaped, connected to the valve body via a rocker arm to achieve rotation around its axis.

Rocker Arm: Supports the valve disc and controls its trajectory, ensuring a tight fit with the valve seat when closed.

Valve Seat: The contact surface with the valve disc is made of hard alloy (such as Stellite alloy) to improve wear resistance and sealing performance.

Performance Advantages of Swing Check Valves

Swing check valves offer significant advantages in various applications due to their unique design and functionality:

1. Simple Structure: Swing check valves require no external control mechanism, operating automatically based on medium pressure and gravity, reducing manufacturing and maintenance costs.

2. Low Flow Resistance: When the valve disc is fully open, the medium flows almost in a straight line, resulting in low flow resistance, making them suitable for high-flow-rate pipeline systems.

3. Wide Applicability: Suitable for various media (such as water, oil, and gas) and pipeline systems of different pressure levels.

4. High Durability: Made of corrosion-resistant materials, swing check valves can operate stably for extended periods in harsh environments.

5. Flexible Installation: Can be installed horizontally or vertically (the valve disc shaft must remain horizontal), adapting to various pipeline layouts.

Limitations of Swing Check Valves

While swing check valves offer numerous advantages, they also have limitations in certain situations:

1. Slower Closing Speed: Relying on gravity for closure, the valve disc's response speed may be slower than that of a spring-loaded check valve, especially under low flow or low differential pressure conditions.

2. Water Hammer Risk: Rapid closure may trigger water hammer, impacting the piping system.

3. Installation Direction Restrictions: To ensure proper valve closure, the hinge axis must be horizontal, limiting installation options.

4. Unsuitable for Pulsating Flow: In systems with frequent start-stop cycles or pulsating flow, the valve disc may vibrate repeatedly, leading to wear or noise.

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