The valve is opened and closed by the hy- draulic system and able to regulate the disc in 90.by quick and slow closing stages and it is can be installed vertically and horizon-tally.The key hydraulic unit are made in USA,Germany and other developed countries which arevery reliable;The motor system is intellegentand controlled by PLC. The key elec-tric components are made in Japan, Germany and otherdeveloped countries. X type-Rubber sealing R type-Metal sealing