What Is a Swing Check Valve Used For

What Is a Swing Check Valve Used For?

A swing check valve is mainly used in piping systems where preventing reverse flow is required, especially in applications with relatively stable flow conditions and where protection of pumps and pipeline equipment is important.

They are commonly installed in:

• Pump discharge lines
• Water supply pipelines
• Wastewater treatment systems
• HVAC chilled water and cooling water systems
• Fire protection pipelines
• Irrigation systems
• General industrial water pipelines

In these applications, swing check valves help prevent reverse flow, avoid pump reverse rotation, and reduce the impact of back pressure on equipment and pipelines.

For medium and large diameter water systems with relatively stable flow conditions, swing check valves are a common and cost-effective check valve solution.

Swing Check Valve Installation and Flow Direction

During installation, first confirm the flow direction arrow marked on the valve body and ensure that the medium flows in the same direction as the arrow. Incorrect installation may prevent the disc from opening or closing properly, which can lead to backflow, leakage, disc impact, or unstable pipeline operation.

Installation Direction

• Horizontal Installation:
  This is the most common and reliable installation method. In a horizontal pipeline, the disc can return to the seat smoothly under its own weight, providing the best check valve performance.
• Vertical Installation:
  Some swing check valves can also be installed in vertical pipelines, but the medium flow is generally required to be upward (bottom to top).

Important Note:
Swing check valves are generally not recommended for vertical downward flow installation. In this position, the disc may remain in a hanging position due to gravity and may not close properly when reverse flow occurs, resulting in ineffective sealing.

Installation Location

During actual installation, the valve should be avoided too close to pumps, elbows, reducers, or other locations that may create turbulent flow.

Stable flow conditions help reduce disc vibration, noise, and the risk of water hammer, thereby improving valve service life and overall system reliability.

Swing Check Valve Water Hammer Problems

During the operation of water systems, swing check valves may experience water hammer, noise, and disc impact problems if the operating conditions are not suitable.

Causes

The disc of a swing check valve opens when pushed by forward flow and closes when the flow stops or reverse flow occurs.

If the pipeline velocity is too high, the pump stops suddenly, or reverse flow develops too quickly, the disc may not have enough time to close smoothly. As a result, the disc can slam against the valve seat, causing noticeable impact noise and pressure fluctuations.

Common High-Risk Conditions

Water hammer problems are more likely to occur in:

• Pump discharge pipelines and long-distance water transmission pipelines
• Systems with high flow velocity or frequent start-stop operation
• Installations where the valve is located too close to pumps, elbows, or reducers

Continuous disc impact not only creates noise but may also damage the valve seat, disc, hinge pin, and pipeline connections, affecting sealing performance and reducing valve service life.

Selection Recommendations

If the system has a high risk of water hammer, it is recommended to consider:

• Swing check valves with slow-closing devices
• Counterweight swing check valves
• Hydraulic damped check valves
• Silent check valves

Instead of directly selecting a standard swing check valve.

The most suitable choice depends on the pipeline velocity, pump start-stop frequency, installation location, medium characteristics, and pressure fluctuations within the system.

Swing Check Valve vs Other Check Valves

Conclusion

Selecting the right swing check valve is not only about preventing reverse flow. The actual application conditions, pipeline design, flow characteristics, and installation requirements should also be considered to ensure reliable performance.

A properly selected swing check valve can help improve system stability, reduce the risk of reverse flow, minimize noise, and lower maintenance requirements.

As a professional valve manufacturer, Union Valve provides swing check valves and other check valve solutions for water supply, wastewater treatment, HVAC, fire protection, and industrial water systems. Union Valve offers different materials, pressure ratings, and connection options to help customers select the most suitable valve solution for their specific operating conditions.Please feel free to contact us if you have any further questions.

FAQ

What is a swing check valve used for?

A swing check valve is mainly used to prevent reverse flow in pipelines and protect pumps, pipelines, and other equipment. It is commonly used in water supply systems, wastewater treatment, HVAC systems, fire protection systems, irrigation, and general industrial water applications.

How does a swing check valve work?

A swing check valve uses a hinged disc mechanism to automatically open and close. During normal forward flow, the pressure of the medium pushes the disc open to allow flow through the pipeline. When the flow stops or reverse flow occurs, the disc returns to the seat position and prevents the medium from flowing backward.

Can a swing check valve be installed vertically?

Some swing check valves can be installed in vertical pipelines, but the medium flow is generally required to be upward (bottom to top). Vertical downward flow installation is usually not recommended because the disc may not close properly, which can result in leakage or unstable operation.

Can a swing check valve prevent water hammer?

A swing check valve can reduce the risk of reverse flow, but a standard design cannot completely eliminate water hammer. If the system has high flow velocity, long-distance pipelines, or frequent pump start-stop cycles, slow-closing designs or other water hammer protection solutions should be considered.