Apparatus for separating abrasive blasting media from debris

An apparatus for separating debris from spent abrasive in an abrasive blasting apparatus in which abrasive is propelled at abrading velocity by a projecting means onto a blast zone on a surface to be treated and debris and spent abrasive are recovered from the blast zone and moved at high speed through a recirculation chamber to a hopper for feeding abrasive to the projecting means, said apparatus comprising

• means for receiving said debris and spent abrasive from said recirculation chamber and allowing a quantity of said debris and spent abrasive to collect thereby forming a pile of said debris and spent abrasive with a face of said pile exposed to incoming debris and spent abrasive from said recirculation chamber;
• wherein said pile has an angle of repose whereby additional incoming debris and spent abrasive strike said pile thereby dissipating kinetic energy of said incoming debris and abrasive, whereafter said debris and abrasive can fall down said face to form a substantially unobstructed, vertical, uniform curtain of falling debris and spent abrasive;
• means for providing a stream of fluid through said recirculation chamber;
• means having a first opening below said receiving means for drawing off a first portion of said stream of fluid from said recirculation chamber,
• wherein said drawing means has a second opening for the passage therethrough of a second portion of said stream of fluid not passing through said first opening, said second portion passing over said hopper and over the abrasive contained therein before passage through said second opening;
• whereby said falling curtain of debris and spent abrasive is washed by each portion of said stream of fluid as the portions flow to the drawing means thereby entraining debris from said falling curtain in said stream of fluid.

An abrasive throwing machine comprising

• an enclosure having an opening therein adapted to confront a surface to be treated with abrasive;
• means within the enclosure for propelling abrasive at abrading velocity onto a blast zone on the surface;
• recirculation chamber means connecting said surface with said projecting means for recirculating spent abrasive from the blast zone at high speed through the recirculation chamber and then to the abrasive propelling means for re-use;
• means for receiving debris and spent abrasive from said recirculation chamber and allowing a quantity of said debris and spent abrasive to collect thereby forming a pile of said debris and spent abrasive with a face of said pile exposed to incoming debris and spent abrasive from said recirculation chamber;
• wherein said pile has an angle of repose whereby additional incoming debris and spent abrasive fall down said face to form a substantially unobstructed, vertical, uniform curtain of falling debris and spent abrasive;
• means for providing a stream of fluid through said recirculation chamber;
• means having a first opening below said receiving means for drawing off a first portion of said stream of fluid from said recirculation chamber;
• wherein said drawing means has a second opening for the passage therethrough of a second portion of said stream of fluid not passing through said first opening;
• and
• whereby said falling curtain of debris and spent abrasive is washed by said stream of fluid as it passes from said recirculation chamber to said drawing means to entrain debris from said falling curtain in said stream of fluid.

An abrasive throwing machine comprising

• an enclosure having an opening therein adapted to confront a surface to be treated with abrasive;
• means within the enclosure for propelling abrasive at abrading velocity onto a blast zone on the surface;
• recirculation chamber means connecting said surface with said projecting means for recirculating spent abrasive from the blast zone at high speed through the recirculation chamber and then to the abrasive propelling means for re-use;
• means for receiving debris and spent abrasive from said recirculation chamber and allowing a quantity of said debris and spent abrasive to collect thereby forming a pile of said debris and spent abrasive with a face of said pile exposed to incoming debris and spent abrasive from said recirculation chamber;
• wherein said pile has an angle of repose whereby additional incoming debris and spent abrasive strike said pile thereby dissipating kinetic energy of said incoming debris and abrasive, whereafter said debris and abrasive can fall down said face to form a substantially unobstructed, vertical, uniform curtain of falling debris and spent abrasive;
• means for providing a stream of fluid through said recirculation chamber;
• means having a first opening below said receiving means for drawing off a first portion of said stream of fluid from said recirculation chamber;
• storage hopper means for feeding abrasive to said abrasive propelling means;
• wherein said drawing means has a second opening for the passage therethrough of a second portion of said stream of fluid not passing through said first opening, said second portion passing over said hopper and over the abrasive contained therein before passage through said second opening;
• whereby said falling curtain of debris and spent abrasive is washed by each portion of said stream of fluid as the portions flow to the drawing means thereby entraining debris from said falling curtain in said stream of fluid.

An abrasive throwing machine comprising

• an enclosure having an opening therein adapted to confront a surface to be treated with abrasive;
• means within the enclosure for propelling abrasive at abrading velocity onto a blast zone on the surface;
• recirculation chamber means connecting said surface with said projecting means for recirculating spent abrasive from the blast zone at high speed through the recirculation chamber and then to the abrasive propelling means for re-use;
• means for providing said stream of fluid through said recirculating chamber;
• means for receiving said debris and spent abrasive from said recirculation chamber and allowing a quantity of said debris and spent abrasive to collect thereby forming a pile of said debris and spent abrasive with a face of said pile exposed to substantially all of the incoming high speed debris and spent abrasive from said recirculation chamber;
• wherein said pile has an angle of repose whereby additional incoming debris and spent abrasive lose a substantial proportion of their kinetic energy upon impacting said face and fall down said face to form a substantially unobstructed, vertical, uniform curtain of falling debris and spent abrasive;
• and
• means having an opening disposed below said receiving means in direct communication with said recirculation chamber for drawing off said stream of fluid from said recirculation chamber, whereby said falling curtain is washed of debris by said stream of fluid by passing the stream of fluid from said recirculation chamber through said falling curtain and into said opening of said drawing means to thereby entrain said debris from said falling curtain in said stream of fluid.