Patent ID: 7688942

Claim:
An element analysis device for analyzing a substance, said device comprising: a transporting means with a measuring region, for transporting the substance to be measured; an outer case; a first case having an exit window, the first case being disposed inside the outer case; a second case having an entrance window, the second case being disposed inside the outer case; at least one excitation source located in the first case the excitation source being oriented such that a fluorescence-exciting radiation from the excitation source impinges on the measuring region; at least one X-ray fluorescence detector located in the second case, the X-ray fluorescence detector being oriented toward the measuring region; and a tube extending from the entrance window of the second case in a direction of the measuring region, the tube being essentially tightly connected to the second case and to the outer case, wherein the tube is completely open at an end facing the measuring region, and is provided with a connection for feeding a flushing gas into the tube, such that the flushing gas freely exits the outer case via the end of the tube facing the measuring region, thereby preventing dust from entering the tube.