... as ash, mud slag, coal slurry, pulp, sewage of solid, liquid-solid ,gas-solid two-phase medium conveying system in the pipeline switching valves ... gate valve features:1, seal by structural ceramics, can prevent solid grain scour, wear to seal face,ensure valve seal lasting ... seal such as Ceramic ,rubber,PTFE and Metal seal.5. Packing: PTFE, reinforce Graphite etc;Size rangeSize:2" -14" or DN50 ...