Swing check valves are among the most common and useful valves in the market. A swing check valve allows fluids to flow in one direction only, giving it some highly practical applications. So, what are swing check valves used for? You’ll find them in plumbing, natural gas and countless other industries. Here’s a closer look at their functionality and typical applications.
How Does a Swing Check Valve Work?
A swing check valve has a disc inside it, which covers the valve’s opening. The disc is on a hinge, allowing the valve to either open or close when the fluid acts on the disc from the one direction. Flow direction is therefore critical with a swing check valve. For a swing check valve to function, the opening has to be entirely clear.
You can imagine a swing check valve disc as a circular door that rotates vertically. When fluid enters the valve in the desired direction, pressure on the disc pushes the valve open, letting the fluid to flow through the valve. However, when the fluid flows in the opposite direction, pressure is applied to the back of the disc, pushing it against its seat to close the valve.
Types of Swing Check Valves
Swing check valves are available in various forms, but two of the most common types are metal and PVC designs. Metal swing check valves are often found in heavy industrial settings.
Deciding the best type of swing check valve for your project begins with understanding the materials used and how the liquids in your project may impact them.
Swing Check Versus Spring Check Valve
A spring check valve is one example of a modified swing check valve. Both spring check and swing check valves have a similar function, but spring check valves use a spring to assist closure and to keep them closed when there is no liquid flowing in the desired direction. While a swing check valve will close naturally under gravity until flow reversal occurs.
The spring in a spring check valve forces the disc to be nearer to the fully closed position when the flow stops and begins to reverse, thereby reducing developed pressure surges within the system.
The addition of a spring in a spring check valve however means that the valve will remain closed until there is a higher pressure acting on the disc to overcome the spring force. This means that more pressure is necessary to open the disc and allow flow through. Subsequently, a spring check valve can impede the flow rate in the system, whereas a swing check valve will have less of an effect.
What Are Swing Check Valves Used For?
If you need a fluid to travel in only one direction and prevent flow in the opposite direction, a swing check valve is likely an appropriate choice. It’s also worth noting that a swing check valve works on the principles of pressure and flow to keep it open or closed, so no external mechanism is necessary for it to function. Swing check valves also enable fluid to travel in the desired direction and pass through without significantly impacting the flow.
So, what are swing check valves used for? The flapper valve inside of a flush-toilet mechanism is a common example of a swing check valve in action. Here, the swing check valve permits water to enter through the bottom of the tank but does not allow it to drain back out (until the toilet is flushed).
Overall, swing check valves are the most common in wastewater and water pumping systems. Other applications include:
- Horizontal water lines
- Natural gas transmission
- Power plants
- Oil and gas refineries
- Custom applications
A swing check valve is probably your best choice if you have a project where backflow could lead to issues.
Finding The Best Fit for Your Project
Swing check valves have several applications, and their simple functionality is almost foolproof, with no need for external power. If you need a modified version of a swing check valve, a spring check valve may be what you’re looking for. Of course, if you’re not sure which valve is the right fit for your project, it’s easy to find out.
If you’re looking for more information on swing check valves and other valves that might be right for your application, John Valves can help. Reach out to us for assistance in finding the valve best suited for your project.