Filter Press is a machine used for solid-liquid separation. Its working principle is based on the pressure filtration, wherein the sludge / slurry is pumped into the filter press and the solids are retained in the press (known as cake) and the solids-free liquid (known as filtrate) separates and flows out of the filter press under gravity. The slurry is fed under pressure via a feed pump which could be centrifugal or screw or peristaltic or any positive displacement pump. The differential pressure causes the filtration to occur thus leading to solids being captured on the filter cloth (placed over a recessed filter plate) thus forming a solid cake. Simultaneously, the clear filtrate keeps flowing out of the machine, which is almost devoid of solids. On reaching a choke-point wherein the filtrate flow stops / trickles down to almost no flow; many a times signals the complete cake formation & thus completion of a batch.