Grain Cleaning Plant An up-to-date grain plant is hardly conceivable without a cleaning plant connected to the intake station even if the grain is only used internally. The dust pollution is reduced, undesirable admixture and green parts are sorted out and the performance of the following conveying and drying plants is optimized. According to the process, pre-cleaners, sieve cleaners and combined units which combine the sieve cleaning with the pre-cleaning, can be used.  It is important to consider the cleaning capacity in a way to avoid a bottleneck at peak time