Method for the dry filtration of a gas flow carrying foreign objects, and filter device for cleaning raw gas carrying foreign objects

A method for the dry filtration of a gas flow carrying foreign objects, in a filter device for cleaning off waste gas produced in additive manufacturing technologies, comprising:

• conducting a raw gas flow containing foreign objects into a raw gas space of a filter unit which has at least one filter surface separating a raw gas side from a clean gas side;
• feeding oxidant to a reaction region located on the raw gas side of the filter surface downstream of the filter surface;
• such that foreign objects contained in material cleaned off from the filter surface and/or in the raw gas flow react in the reaction region with the oxidant to form oxide-containing foreign objects;
• wherein the reaction region is located downstream of the raw gas space with respect to the transport of foreign objects that have accumulated on the filter surface and have been cleaned off from the filter surface wherein oxide-containing foreign objects formed during the reaction and, if present, foreign objects not yet reacted are discharged via a pneumatic conveyor.