Device for the post-treatment of exhaust gases of an internal combustion engine

An apparatus for posttreatment of exhaust gases of an internal combustion engine, using a reducing agent to be introduced into the exhaust gases, in particular a urea or a urea-and-water solution, having an improved mixing chamber into which stored reducing agent, via a reducing agent line, and compressed air via a compressed air line can be introduced to create a reducing agent-air mixture, and means for preventing a reverse flow of reducing agent or reducing agent-air mixture from the mixing chamber into the compressed air line are provided which have a spring-loaded sealing hose. This arrangement assures secure sealing off of an attachable compressed air system from the corrosive reducing agent.