| 摘要 |
<p>Absorption of treatment composition into a surface layer of particulate material in a moving bed is substantially increased by spraying a major portion of the composition through a first group of nozzles and a minor portion of the composition through a second group of nozzles, the nozzles being attached to the top of a common transverse spray header which is oscillated across the moving bed. The first group of nozzles directs a plurality of substantially parallel vertical jets onto the surface of the moving bed to form therein, on combined motion of the bed and spray header, a ringing pattern of trenches. The treatment composition is retained in these trenches as it is absorbed by adjoining particulate material. Loss of treatment composition due to run-off over a sloping or insufficiently wetted surface is avoided. The second group of nozzles is provided with deflectors which cause downwardly discharging fluid to fan out in spray curtains which together extend across the moving bed to ensure wetting of areas between the zigzag trenches.</p> |
