Our check valves are equipped with a diaphragm to prevent the return of liquids and gases. When the membrane is closed, a very low noise level is generated and water hammer is avoided. The backflow prevention valve also provides a reliable closure for granular liquids (e. g. with sand). Our device also acts as a raw filter, protecting pumps and systems. In addition, we guarantee a long product life as there are no mobile electronic or mechanical modules subject to damage.