Non-return valves

The task of non-return valves or backflow valves is to prevent the flow of the media in a certain flowing direction.

Our product range covers all non-return valve models used in the industry. They can be divided into four groups.

The most conventional models are flanged or welded non-return valves up to PN 40, which are manufactured by ARI.

Flanged valves in our product range are manufactured by GESTRA. According to the nominal size, pressure rating and, above all, pressure loss, a model suitable for a certain process can be selected from our product range of Disco, flap non-return valves or dual-butterfly non-return valves.

Our product range also includes lined non-return valves, in which the lining protects the valve body against corrosive media, for example. The most common lining material is PTFE; as a synthetic material, it prevents dirt and corrosion from sticking to surfaces in contact with the media and protects against mechanical wear.

It is also important that non-return valves are dimensioned and not selected based on the pipe size only. Dimensioning ensures correct opening and closing of the non-return valve as compared to flow rate. Excessive nominal size and low flow rate can result in a situation where the valve never fully opens and its wear parts are subject to constant mechanical stress. This is often manifested by so-called continuous non-return valve clinking. Naturally, this reduces the service life of the valve. For such applications, we particularly recommend the DSF-type non-return valve manufactured by ChemValve, the structural solution of which prevents the aforementioned problem and the design of which grants significantly better transmission as compared to a conventional non-return valve of the disc type.

Our product range also covers ASME non-return valves up to the pressure rating of 2500#, as well as non-return valves that can be locked in the open position.

In addition, the seat valve range of ARI Armaturen also includes a closable non-return valve.

Additional information on non-return valves is available in the Gestra general brochure.