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Check Valves

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Stainless Steel Vertical and Swing Check Valves

Check valves are a device used to prevent backflow of water, gas, fuel, or other media in a system. They are unidirectional, allowing media to flow in one direction only. They are also commonly known as non-return valves and one-way valves.

The two types of ESV check valves are swing check valves and vertical check valves, described below.

Swing Check Valve

Also known as tilting-disc check valves. This type of check valve is designed to control flow direction using a disc that swings freely on a hinge. As liquid or gas flows through the swing check valve, the disc swings open allowing the media to pass through. When the pressure drops, the disc swings back into its original position, creating a seal, stopping any backflow.

A swing check valve is recommended when your application requires flow not to be constricted. They can be installed horizontally or vertically, but only vertically when the fluid flows from the bottom up. 

Vertical Check Valve (Spring-Loaded)

Also known as spring check valves and spring-loaded check valves. Gravity and backflow are used by swing check valves to close, but for a spring loaded vertical check valve, a spring holds the valve shut until enough pressure pushes against it to force the spring back, opening up the valve. When the flow pressure drops below the cracking pressure, the spring will force the valve shut.

Vertical spring check valves can be installed in any orientation (vertical or horizontal) and provide a stronger backflow prevention than a swing check valve.

Check Valve FAQ

What does a check valve do?

Check valves are installed into fluid control systems to prevent backflow. The main reasons for this are to provide pressure relief for system safety, prevent contamination from reverse flow, and prevent equipment upstream from backflow damage.

How does a check valve work?

There are several different types of check valves, but they all follow the same basic mechanisms to function. These types of valves are controlled by pressure, opening the valve when there is more pressure coming from the inlet, and closing when there is no inflow pressure or when more pressure is coming from the outlet.

Can you install a check valve with a solenoid valve?

Yes, we highly recommend installing a check valve downstream from all solenoid valves. Backflow or back pressure will cause most diaphragm operated solenoid valves to malfunction. A check valve is an easy to install device that can protect your solenoid valves and extend their product life.

What direction do you install a check valve?

When looking at the side of either a swing check or a vertical check valve, there is an arrow that depicts the required flow direction.

Do check valves stop water hammer?

Check valves can prevent water hammer, though not all types of check valves are recommended for this. Swing check valves can actually cause water hammer if the valve swings too slowly (allowing back pressure) or too quickly (abruptly slamming shut). Spring check (vertical check) valves are the best choice for minimizing or preventing water hammer since the valve closes as the pressure drops, before the flow direction changes.