The changeover valve allows Duplex filters continuous operation even during the cleaning phase. Duplex filters are primarily used in applications where service shutdowns are not practical or they are uneconomical. The SAB product portfolio covers Duplex filters for almost every application! With our wide range of products, we are able to filter liquids and gases. From cast Duplex filters (in stock) for water applications, to welded filters certified with TÜV or any other third party approval for highly aggressive fluids.