Check Valve Types: Their Functions and Applications

Check valves are essential tools used in fluid systems. They prevent reverse flow and help protect your equipment. 

To learn more about check valves, it’s important to know about their common types and how they operate automatically.

So, read on to get to know the 5 most common check valve types and where they are used.

What is a plumbing check valve?

A plumbing check valve is a device that allows water to flow in one direction only. It stops water from flowing backward, which helps prevent contamination and damage. 

Moreover, the valve automatically closes when the flow stops or reverses. This mechanism allows proper water flow in plumbing systems.

Types of Check Valves, Their Functions and Applications

There are 5 main check valve types and each type has unique features for specific uses. Learn more about them below.

#1. Lift Check Valves

Lift check valves have a guided disc that lifts off the valve seat when there is inlet pressure, which allows fluid to flow through. 

The disc’s shape is like a piston or ball, and it moves in a straight line to reseat properly. 

Then, gravity and backflow push the disc back onto the seat when the flow stops or reverses, sealing the valve.

Applications:

• High-pressure environments.
• High-rise building water systems.
• Water and wastewater treatment facilities.
• Pumping systems in industrial plants and power stations.
• Steam, air, gas, and water systems with high flow velocities.

Furthermore, lift check valves are ideal for high-pressure and high-velocity applications. They provide reliable and quick closure to prevent backflow.

#2. Swing Check Valves

Swing check valves have a simple design. They have a hinged disc that swings open to allow flow and closes due to gravity and reverse flow. 

When it comes to availability, swing check valves are common and typically inexpensive.

Applications:

• Low-pressure systems with low flow rates
• Wastewater treatment plants
• Gravity drainage systems
• Pump discharge lines

Application and durability-wise, swing check valves work well in low-pressure and low-flow systems. 

They are suitable for wastewater and gravity drainage, where flow control is not critical.

#3. Ball Check Valves

Ball check valves use a free-floating ball inside the valve body. This ball controls the direction of flow. Then, the ball rotates during operation to prevent particles from getting stuck. 

Some ball check valves have a spring, while others rely on reverse flow to move the ball into the seat for sealing.

Applications:

• Highly viscous fluid services
• Slurries and fluids with suspended solids

Furthermore, ball check valves are suitable for systems with viscous fluids and slurries. The ball design ensures smooth operation even with particulates.

#4. Tilting Disc Check Valves

Tilting disc check valves are similar to swing check valves. They have a disc that tilts on an off-center hinge. 

This design provides a streamlined profile and allows faster closure than swing check valves.

Applications:

• High-pressure applications
• High-flow rate systems

Tilting disc check valves are effective in high-pressure and high-flow rate environments. They provide a quick response to maintain system integrity.

#5. Nozzle Check Valves

Nozzle check valves have a disc connected to a stem guided along a central axis. A spring is positioned between the disc and a diffuser sleeve. 

Flow compresses the spring to open the valve. When the flow stops, the spring forces the valve to close quickly.

Applications:

• Quick closing applications
• High-pressure systems

Nozzle check valves are designed for rapid closure. They prevent water hammer and reverse flow, especially in high-pressure systems.

Note: A water hammer is a surge in pressure when a tap or valve is rapidly closed or switched off. This typically results in loud, knocking noise in the pipes.