Diefenbach thickeners are comprised of a tank, feed pipe feedwell, rake (and pickets, depending on the thickener style), a bridge containing the rake drive mechanism, and a chemical dosing system.
The slurry feed enters the thickener from a de-aeration tank and into the feedwell. Chemicals are added to the feed to aid in rapid settling of the solid particles in the slurry. These chemicals can be flocculants or coagulants, depending on the application. They attract the fine solids in the slurry to form larger, heavier particles that sink to the bottom of the tank.
As the flocculated solids settle to the bottom of the tank, the rotating rake mechanism assists with moving them toward the discharge cone in the center. The thickened solids are then discharged out the bottom of the tank and, depending on the application, sent to waste or further processing.
The solids-free liquid (or liquor) overflows the weir surrounding the top of the tank. Again depending on the application, this clarified liquid is then sent for further processing or reuse as process liquid.
