... the opening and closing of the vavle, the gate disc can automaticallly scrape off the adhered medium and ... is beneficial to sealing.3.The blade type gate disic helps medium cutoff anf residue discharge so ... JB/T79, HG, SH, JIS, DIN, NF, BSMain materials: C.I,WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12MoTi, CF8, CF8M, CF3, 2Cr25Ni20Seal type: ... manual, umbreall, gear, electric Wafer rising Stem Knife Gate Valve