| 摘要 |
Parts (12) to be treated are placed in grid bottomed tubs (14a, 14b, 14c) and the tubs (14a, 14b, 14c) are stacked one upon the other. A flow of treating gas is directed exteriorly about and internally through the tubs (14a, 14b, 14c) from an entrance end (26) to an exit end (28). If the parts (12) in the entrance tub or tubs (14a, 14b) are sufficiently but not overly treated, it has been found that the parts (12) near the exit end (28) of tub or tubs (14b, 14c) are not sufficiently treated. If the parts (12) near the exit end (28) tub or tubs (14b, 14c) are sufficiently treated, then the parts (12) in the entrance end (26) of tub or tubs (14a, 14b) are over treated. This problem is solved by providing a member (31) having at least on lateral aperture (32, 32' or 32'') in a stacked column (16) of the tubs (14a, 14b, 14c) intermediate the ends (26 and 28) thereof and provides a flow of gas through the aperture (32, 32' or 32'') from the exterior of the column (16). This provides a proper gas concentration in the tub or tubs (14b, 14c) near the exit end (28) as well as in the tub or tubs (14a, 14b) at the entrance end (26). |
