Patent ID: 8715511

Claim:
Apparatus for separating grit from liquid sewage while retaining organic solids in suspension including inlet means for admitting liquid sewage into the apparatus, outlet means for removing liquid from which grit has been separated from the apparatus, and means for removing separated grit from the apparatus, the apparatus further comprising: a cylindrical grit settling main chamber defining a bottom end portion, a top end and a peripheral wall; a grit storage secondary chamber positioned below the main chamber bottom end portion such that grit settling out of the liquid will settle into said secondary chamber, said secondary chamber including a central grit settling access top mouth opening through said main chamber bottom end portion; a vertical shaft positioned centrally in said main chamber and in said secondary chamber, said shaft having a longitudinal axis; means for causing rotation of said vertical shaft about said longitudinal axis; a partition extending transversely through said main chamber intermediate said top end and said bottom end thereof spacedly therefrom wherein an upper subchamber is formed in said main chamber above said partition and a lower subchamber is formed in said main chamber below said partition, said liquid sewage inlet means in direct fluid communication with said lower subchamber, said liquid outlet means in direct fluid communication with said upper subchamber, said partition having a peripheral edge integrally mounted in substantially fluid tight fashion to said peripheral wall of said main chamber; said partition including a bottom central aperture housing said shaft, said partition bottom central aperture being spaced from said shaft to define an annular opening between said shaft and said partition to provide for upward flow of liquid from said lower subchamber to said upper subchamber; and mechanical means positioned within said main chamber, said mechanical means enabling a sustained rotational liquid sewage first fluid flow within said lower subchamber, said mechanical means enabling an induced upward liquid sewage second fluid flow from said lower subchamber through said partition annular opening and into said upper subchamber, and said mechanical means enabling a sustained rotational liquid sewage third fluid flow within said upper subchamber for escape through said outlet means, wherein a fluid flow speed gradient is established between said liquid sewage third fluid flow and said liquid sewage first fluid flow.