To provide a filtration device for filtering very fine powder, which filters out the very fine powder, while reducing and/or detecting the generation of a tear and/or a covered section of a sieve screen.

A sieve screen level detector for the filtration device (10) for filtering the very fine powder material (M) is provided with a material inlet (24) and a material outlet (26), and the sieve screen (14) arranged in a sieve (12) between the material inlet (24) and the material outlet (26), so that the material (M) comes out of the sieve (12) by reaching the material outlet (26) through the sieve screen (14). An inlet valve (22) controls the flow of the material (M) which enters in the sieve (12) through the material inlet (24). A sieve screen level detector assembly (20) detects the level of the material (M) accumulated in the sieve screen (14), and sends a level detection signal (66) indicating the level. A programmable logic controller (60) receives the level detection signal (66), and controls at least partially the inlet valve (22) based on the received level detection signal, and thereby controls the flow of the material (M) into the material inlet (24).