How does a precoat filter maintain a fresh filtering surface for slimy solids?

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To maintain a fresh filtering surface when dealing with slimy or gelatinous solids, a precoat filter utilizes a specific mechanical process:

Initial Layer: A layer of filter aid, typically one to two inches thick, is deposited onto the drum of a rotary vacuum filter before the filtration process begins.1
Continuous Removal: As the filter drum rotates, a blade continuously cuts away thin, successive layers of both the precoat and the accumulated slimy solids.1
Surface Renewal: By shaving off the clogged material, the process exposes a fresh, nonblinded surface of the precoat to the slurry, allowing for continuous and efficient filtration.1

This technique prevents the filter from becoming "blinded" or clogged by the compressible nature of the slimy precipitate.1