The pinch valve can be used for granulates, liquids containing solid particles and highly viscous, fibrous, powders and abrasive media.
Usually they are only available in a normally open version (without open compressed air supply), but Festo now also has a normally closed (N/C) version.
The pinch valve does not require a separate actuator, but is basically a hose in a housing in which an air pressure can be placed on the outside of the hose to push the hose shut. In many cases, the internal hose can easily be replaced. When open, the pinch valve has an almost full passage. If media with particles go through it still closes completely because the hose squeezes itself around the particles.
There are even applications of the pinch valve where, for example, concrete is used as a medium and the valve is operated under water with compressed air.