What is the difference between a non-return valve and a check valve?

Under UK plumbing regulations, the ‘check valve’ has a specific purpose as a device legally permitted to be used to prevent backflow in defined circumstances. The non-return valve, while useful for preventing reverse flow in pipes in many situations, is not a recognised backflow prevention device.

Is non-return valve a check valve?

A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction.

What is non-return valve used for?

A non-return valve allows a medium to flow in only one direction and is fitted to ensure that the medium flows through a pipe in the right direction, where pressure conditions may otherwise cause reversed flow.

How does a non-return check valve work?

Non-return valves work by allowing media to flow through them in only one direction. These valves have two openings in the body, one for media to enter and the other for media to leave. Non-return valves work automatically, which means that most are not controlled by a person or an external control.

How does a non-return valve work?

Non-return valves are flow sensitive, and rely on the steam flow to open and close. The internal disc opens and allows the flow of steam through the valve. The disc will begin to close as forward steam flow decreases or is reversed, depending on the design.

What is a non-return valve?

Non-return valves are e.g. used with mixing loops in heating and cooling systems to ensure proper operation, and with domestic water systems to prevent backflow. Illustration: Clapper type non return valve.

What are the types of check valve?

The principal types of check valves used are the tee-pattern lift check, the swing check, the tilting-disc check, the Wye-pattern lift check, and the ball check, illustrated in Figs. A to E, respectively.

What is a non-testable dual check valve?

The Zurn Wilkins 700XL Dual Check Valve is a non testable device used in low hazard potable water applications. It protect against both backsiphonage and backpressure of polluted water into the potable water supply. To view all options, see the Specification Sheet – Model 700XL