Union flat seat malleable cast iron

  Datasheet (PDF)

The Georg Fischer union flat seat 330 (ISO/EN U1) is a three-piece demountable pipe joint engineered for rigid threaded piping installations requiring regular inspection, maintenance, or line servicing. Comprising an internal-thread union bush (figure 370), a flat-faced union end (figure 372), and an external fastening union nut (figure 374), the assembly achieves a secure, tight seal by drawing the opposing flat seating faces into axial compression against an elastomeric or fibrous flat gasket. The connection utilizes parallel internal pipe jointing threads (Rp) compliant with EN 10226-1 and ISO 7-1 to ensure reliable sealing on the connecting pipe threads, while the union nut engages cylindrical fastening threads (G) manufactured according to EN ISO 228-1. Cast from premium decarburised annealed whiteheart malleable cast iron type EN-GJMW-400-5 in strict accordance with Design Symbol A of EN 10242 and ISO 49, this component provides superior structural stability, exceptional impact strength, and dependable vibration absorption. Available in a black protective finish or a high-purity hot-dip galvanised zinc execution compliant with drinking water hygiene standards, the fitting exhibits long-term resistance against corrosion and aggressive industrial atmospheres. Designed for utility networks, cooling installations, compressed air loops, and liquid distribution systems, the union reliably operates up to a maximum permissible pressure of 25 bar across temperatures ranging from -20 degrees Celsius to 120 degrees Celsius, and up to 20 bar at temperatures reaching 300 degrees Celsius, with intermediate working pressures determined through linear interpolation. The three-part flat-seat architecture allows complete disconnection and radial clearing of pipe segments without cutting or dismantling adjacent runs, enabling swift component exchange in compact plant configurations.