They sieve the flour and imitate the action of a hand sieve. Each one of the boxes in the "Plansichter" is divided into four channels, which are different sizes to separate the different sized products and send each to the corresponding machine.

In 1880, the German Haggemacher patented this sieving machine, called a "Plansichter", which was used to imitate a manual sieve, and saw a significant improvement in the quality of the flour.