This ProfiDrum replacement screen will fit the ProfiDrum Combi Bio 30 drum filter, they are 75 micron 120 cm x 40 cm, for the ProfiDrum Combi Bio 30 you only need to buy one screen.
The water enters the profidrum through the inlets on the dirty side of the drum, the water contains mechanical waste that flows through in to the centre of the drum where the 75 micron screen catches the mechanical waste until the water level on the clean side of the drum drops past two probes that trigger the drum to rotate and at the same time trigger the high pressure pump to jet the dirt trapped on the screen down a stainless steel waste chute to waste. The water level on the clean side of the drum returns back to its normal clean level.
The dirt is caught in elongated slots composite screen panels a little like how a water wheel works inside the drum this lifts the dirt out the water up and over the chute and ejected to waste through the waste chute. This cleaning process uses about 1.5 ltrs of water.