This machine features an air flow which stirs the material while keeping the screen meshes constantly free. No mechanical action is used. The air flow is created by an electric extractor fan. A rotating bar located under the screen directs the flow onto the test material. The flow automatically seals the screen and the cover which are both fitted with suitable rubber gaskets. The material passing through the test screen is extracted and taken to the electric extraction fan filter. The screener works just with one 1 screen, ø 200 mm, 25 mm high (Supplied on request).