D-1210Recessed Plate Filter Press

How it works

1. The idea — Pump sludge into a closed chamber lined with cloth. Water goes through the cloth, solids cannot, and what stays behind builds into a cake. There is no settling and no gravity anywhere in it — which is why a press does not care whether the solids are denser than water.
2. The cake becomes the filter — Within minutes the cloth stops mattering. The cake itself is the filter medium, and it grows thicker and more resistant every second. That is why filtration time rises with the square of the volume filtered — and why the last litre takes many times as long as the first.
3. Alpha is measured, not assumed — The specific cake resistance α spans four orders of magnitude between an unconditioned sludge and a lime-conditioned one. Plot t/V against V from a leaf test and the slope gives you α directly. Design a press without it and you are guessing at the cycle time.
4. The cake meets in the middle — Cake grows inward from both faces at once. When the two halves meet, filtration is over — not because a timer said so, but because there is nowhere left to put anything. That is why chamber thickness, not pump pressure, sets the cycle.
5. The cycle is not all filtration — Close, fill, filter, squeeze, blow, open, discharge, wash. On a small press the handling can exceed the filtration, and when it does, more pump pressure buys you nothing at all. Push the handling time up and watch where the bar goes.
6. The recessed plate — Two dished plates bolted face to face make a chamber; the cloth lies over both. Cheap per square metre, mechanically simple, and the cake it drops is already drier than anything a continuous machine produces. Its weakness is the discharge — the cake has to fall out under gravity, and sometimes it does not.

Design parameters

The panel opposite runs the same correlations as the D-1210 design sheet, so the animation and the calculator cannot disagree. Every parameter below is live — drag one and the picture responds.

Open the full D-1210 design sheet for the other two inputs, all twenty-nine results with their envelopes, the six equations printed beside the numbers they produce, and a calculation record you can export and put in a design file.