| 摘要 |
<p>Apparatus for treating a surface 19 has an impeller 11 for delivering particulate abrasive down a delivery section D to hit the surface 19 and the abrasive, mixed with debris from the surface, passes up a rebound section R to a separator section. The mixture hits surface 34 and falls onto and over a weir 35, 36, passes through gap 38. Large debris is removed by filter 40, very fine dust is removed by suction device 32, more debris is removed by filter 45, further filters 47c, 50a remove debris and too small abrasive and the abrasive returns to abrasive hopper 43 and thence to the impeller. Fresh abrasive is supplied through passage 84. The section R is in four channels 21. Adjustable wear plates are positioned in section D. A controlled air stream is admitted to the rear of treatment region 60 through a passage 71 which is provided with an adjustable flap 71b. The section D may be tapered downwards. The lower parts of sections R, D are integral with region 60 and have an overall size. <IMAGE></p> |
