Knife gate valve NBR pneumatic actuation double acting DN50-DN600 Knife gate valves are designed mainly for on-off and isolation services in systems with high content of suspended solids. Knife gate valves are especially beneficial for handling slurry in addition to viscous, corrosive and abrasive media. The valves have a minimised pressure drop in fully open position, they are easy to actuate, they have a relatively low weight and are cost-effective.