Apparatus for cleaning surfaces, including means for separating debris and abrasive material

An apparatus for the treatment of a surface with particulate abrasive material projected at high velocity comprising:

• (a) projecting means for propelling a stream of particulate abrasive material against the surface to be treated;
• (b) a vertically disposed cleaning chamber for removing debris from abrasive material propelled toward and rebounding from the surface;
• said cleaning chamber having an upper inlet for receiving abrasive material and debris;
• (c) a recovery conduit for receiving and directing a stream of abrasive material and debris rebounding from the surface to said cleaning chamber inlet;
• (d) said cleaning chamber further comprising a plurality of vertically arranged compartments;
• (e) each of said compartments including a first vertical wall and a second vertical wall opposite said first vertical wall and further including a solid inclined baffle extending from said first vertical wall toward said second vertical wall and terminating short of said second vertical wall to provide a passage adjacent said second vertical wall for passage of abrasive material and debris from one compartment to the next lower compartment;
• (f) a plurality of first openings in said second vertical wall for admitting air to said compartments, each of said first openings being arranged between successive baffles;
• (g) a plurality of second openings in said first vertical wall for discharging air and debris from said compartments, each of said second openings being immediately below a corresponding one of said baffles;
• and
• (h) means for causing air to move transversely of said compartments from each of said first openings through the corresponding compartment and for discharging the air and entrained debris through the corresponding second opening;
• (i) abrasive material and any remaining debris being caused to flow down each said inclined baffle and to be discharged from the end thereof into a corresponding one of said passages directly above the next lower one of said first openings.