... 20 series Material:Cast iron /Ductile iron /WCB "U" type butterfly valve:1) Material: body-CI/DI/WCB 2) Disc: ... supply,shipbuilding, medicine and metallurgy industries. Equipment are used for regulatingor cutting off media in pipelines. Suitable media include water ... , sewage, seawater, air, foodstuff and oil. Suitable for handles (DN50~300), gear operators,electric and pneumatic control actuators ...