Tubular screw feeders and trough screw feeders are used for high flow rates and also to bridge differences in height. They can be employed in just about any kind of production plant. Screw heat exchangers not only convey the product but also heat/cool it in the process. Screw activators are used to discharge large amounts of bulk material with difficult or poor flow properties. Because several screw spirals are installed next to each other in a housing, the activation effectis excellent. Moisting screw feeders are used for moisting of very fine, dusty and possibly polluting bulk material, e.g. for ash-handling.