|Most Belt Filter Press operations can be divided into three general stages -
initial de-watering, which makes the sludge pulp; pressing or medium pressure filtration, which conditions
the sludge for high pressure filtration quality; and high pressure filtration, which raises the dry solids
content in the sludge cake to the optimum.
The process begins as the sludge enters the press, where it is mixed with a chemical , either in the press,
or in a conditioning tank prior to the press. From this flocculation or preparation zone the sludge enters
the gravity drainage zone (#2 and #3 on below illustration), where a large rotating drum agitates the floc and
drains approximately 70% of the free water. The resulting capture rate can be as high as 99%.
Pressure is first applied in a low pressure wedge zone (#4), which begins squeezing remaining water out of the sludge.
Further de-watering occurs in the medium pressure zone (#5). where two large perforated drums of decreasing size apply the
pressure. Rollers perform the final de-watering in the high pressure zone (#6). The sludge cake (filtered solids)
then exits the machine at (#7). (#8) indicates the locations of the belt cleaning spray stations. The belting on
a belt filter press must be continuously washed with clear water to keep it from blinding, and this is accomplished
by water spray bars placed above returning belt.
Belt Filter Presses are used in mining, mineral processing, municipal waste treatment, industrial and some
The photo at right shows a Roediger Belt Filter Press.
|Illustration Of A Working Belt Filter Press