In the protection type tests (IP5X, IP6X, IP 5 KX and IP 6 KX), the test material (weighing up to 1000 kg) is exposed to dust for a defined period of time. The dust corresponds to the composition specified in the standards. It is distributed homogeneously in the test system and must remain as dry and lump-free as possible. The scraper system conveys the test dust from the dust chamber to the blow-out unit with low noise emission. This blows it into the test chamber either cyclically or continuously via four channels. The blown-out dust collects in four hoppers under the test chamber. From there, the dust conveyor system transports it back into the dust chamber.