What's the Difference: Swing Check Valves & Non Return Valves

THE PETER SMITH VALVE COMPANY LTD WWW.PETERSMITHVALVE.CO.UK WHAT'S THE DIFFERENCE? CHECK VALVES & NON RETURN VALVES. "Check Valves' and 'Non Return Valves' are often confused to mean the same device when it comes to preventing backflow in pipes and fittings. They are in fact different designs of valve fitting, serve different purposes and fit under conflicting UK plumbing regulations. NON RETURN VALVE CНЕCK VALVE The Check Valve's design uses the 'Obturator', a moving element that is kept open by the The simplest design of a Non Return Valve is that it comes with a weighted flap, which is held open by flowing water. If the flow reverses, the flap will close under its weight and is kept closed by backpressure. forward flow of water. If the flow stops, the 'Obturator is held on the valve seat by spring action, facilitated by backpressure, closing off backflow. Under UK plumbing regulations, the Check Valve is considered a legally permitted device to be used in backflow prevention. However, while the Non Return Valve is useful for preventing reverse flow, it is technically not a recognised device and has to meet less demanding standards than the Check Valve. The confusion over names has led to many cases where installers have purchased Non Return Valves unknowingly, only to have them replaced by Check Valves when a water supplier re-inspects a water system. SWING CHECK VALVE These valves allow flow in a single direction and automatically prevent back flow (reversed flow) when fluid in the line tries to go back in the opposite direction. Here is a diagram of a Swing Check Valve. SWING CHECK VALVE Fig. 184SC Also Fig. 184SCLW c/w outside lever & weight for quick closing of valve. HINGE PIN COVER FLOW IN FLOW OUT VALVE BODY SEAT RING DISC FLOWPATH OPENED Fig. 184SCRF c/w rubber faced disc. BENEFITS OF A SWING CHECK VALVE Self-automated Unlike some other types of valve, they do not require assistance to open and close. Not limited by external factors They continue to work even if the environment around them loses air, electricity, or a person that may be controlling them. The Peter Smith Valve Company Limited are specialists in the design and manufacturing of Swing Check Valves and other small to medium high quality valves for the control of fluids and gases in most pipe conveying systems. For more information on our products visit www.petersmithvalve.co.uk Peter Smith Valve Company Limited Occupation Road, Cinderhill Road Bulwell, Nottingham THE PETER SMITH VALVE COMPANY LTD NG6 8RX T: +44 (0)115 927 2831 www.petersmithvalve.co.uk