Non Return Valve VS Check Valve

Fluid control in industrial pipes is imperative to keep large scale operations running. These fluids are controlled by the opening/closing of valves.  Out of the many valves available, two are known as check valve and non return valve. 

While both these valves allow unidirectional fluid flow, the main differences arise in their structure. Unlike the check valve, the non return valve is better suited to water retention purposes as it comes with specially designed components to block backflow. In this article, we’ll tell you more about the differentiable features between the two.

Differentiating Between Non Return Valve and Check Valve

Working

When looking through industrial pipes, you’ll most often find check valves. Also known as one way valve, these have a very simple structural makeup. The one way valve comes with one distinct passage.  

The start of the passage marks the inlet and the end marks the outlet. Fluid flows through the one way valve using the concept of pressure differences also known as cracking pressure. Cracking pressure refers to the lowest amount of pressure needed to allow fluid flow. A higher pressure at the inlet and a lower pressure at the outlet allow fluid flow. These valves are designed to prevent backflow. 

On the other hand, we have the non return valve. The ball non return valve is ideal for fluid control situations as it’s known to block reverse fluid flow which may happen due to sudden drops in pressure or lowered fluid supply. Like the one way valve, these allow fluid flow in the non return valve symbol direction only. So, what’s the difference?

The larger difference lies in their structural makeup. The double non return valve allows fluid flow once it opens when there is enough pressure. However, once fluid flows in the opposite direction, the force of the fluid closes the valve with the help of gravity. The one way valves don’t come with a closing component which blocks off all backflow.

Operational Use

The fluid flow in pipes follows the check valve direction making these valves the optimal choice for unidirectional situations. Any time the flow is reversed, it can cause water hammer effects. And these are then followed by high pressure flow which may further cause damage to the piping systems. If the system doesn’t fail immediately, it can lead up to complete system failure as the water hammer effects continue to build up. 

The one way valve is found here:

• HVAC Industry
• Power Plants
• Mining
• Food Industry

High pressure non return valves are more often found in more common everyday applications. Unlike check valves, these are not often used for industrial operations. Instead, you’ll find them in areas like:

• Cooling Systems
• Housing Water Pipes