US Patent 11759796 Air treatment apparatus

A docking station for a robotic surface cleaning apparatus has a momentum separator. The momentum separator has a plurality of walls comprising an upper wall, a lower wall and a first sidewall, wherein the first sidewall extends between the upper and lower walls, and wherein the first sidewall comprises a side screen. A first end wall is spaced from and faces the side screen wherein an up flow chamber is positioned between the first end wall and the side screen.