Demonstration filter liquid control circuit

Claim 1

Liquid and solid circuit for demonstration vacuum filter, which filter is provided with a tank for retaining a liquid-solid mixture to be filtered, a rotating drum filter mounted to have its lower portion immersed in liquid in said tank, said filter being of the type having: a vacuum conduit connectable outside of said filter, designed to remove filtrate from the inside of said fiLter when an exterior vacuum is applied thereto, a pressure conduit connectable outside of said filter designed to provide an air flow outward through those portions of the filter material from time to time above the liquid level in said tank, means, including said air flow for depositing outside said filter, solids filtered by said drum filter out of a liquidsolid mixture in said tank, the liquid and solid circuit comprising: a supply conduit for supplying a liquid-solid mixture to said tank, means connecting said pressure conduit to a source of gas under pressure, means connecting said vacuum conduit to a chamber, means for creating a vacuum in said chamber, said chamber being designed to store liquid withdrawn from said filter chamber, a pump connected to pump liquid from said vacuum chamber, when the liquid level therein is above a predetermined amount and not to pump when said level is below a predetermined amount, a reservoir located to receive liquid pumped from said vacuum chamber, said reservoir being located to receive solids filtered by said drum filter and deposited outside said filter, means in said reservoir for causing mixing of said liquid and said solid, an exit from said reservoir at a predetermined height therein, said supply conduit leading from said exit to the filter tank, and a pump in said supply conduit operable to pump liquid reaching the level of said exit into said tank.