Backflow preventer as intermediate flange clamp fitting, double flap construction, with closing springs for horizontal and vertical lines with flow upwards. With special springs also for flow downwards. Centering on the housing. Suitable for liquids, gases and vapors.
Optionally metallic or elastic sealing. With closing damping for pressure shock hazard plants. Housing levasint-coated or gummed for use in drinking water or in the seawater area.