The threaded end backflow ECO 3T preventers, with controllable reduced pressure zone type BA EN1717 are approved in conformity with EN12729 and are manufactured in accordance with the most severe product norms and in conformity with the quality requirements of EN ISO 9001. The body of dimension DN 15 is made of brass and the body of dimensions DN 20-50 is made of bronze.
They consist of 2 spring check valves and a chamber situated in between the spring check valves, which contain a security valve, which in the event of “backflow”, isolates the primary network from the user network. The backflow might be caused by siphoning (the entry pressure decreases due to ruptures in the piping upstream, the water supply is interrupted, draining off parts of the piping due to events upstream) or the build up of counter pressure (the pressure of the user network is higher than the pressure in the primary network due to overpressure caused, for example, by incoming water pumped from a private water well). Backflow preventers are indispensable to prevent contamination of the distribution network of the drinking water from connect user units (for example, washing machines, boilers, industrial plants, hospitals, laboratories, fire fighting plants).
For correct installation, it is necessary to install a filter upstream with respect to the backflow preventer, in order to avoid problems caused by dirt and residual parts present in the piping, such as shut-off valves upstream and downstream with respect to the backflow preventer. Series ECO3T backflow preventer, even if marked PN10 for the purposes of reference normative EN12729, due to its design and testing characteristics is suitable for installation in firefighting networks with service presure of 12 bar.