| 摘要 |
655,814. Etching-apparatus. HUNTERPENROSE, Ltd. Oct. 21, 1948, No. 27417. [Class 100 (ii)] A dusting cabinet 15 for the application of dragons blood or other media in powder form to photographically-prepared printing-plates comprises a hood 1 enclosing a dusting tray 9, the front of the hood being open and the back of the hood having an exhaust opening 12 connected by ducting 13 to a filter chamber 14 associated with a fan 16 so that powder drawn from the hood is extracted in the chamber and clean air passes to the fan, thus preventing the occurrence of blow-backs in the hood. The cabinet comprises front and rear walls 17 and 18, and side walls 15 extending downwardly from the hood 1. The cabinet is divided by a vertical partition 20 in front of which drawers 21 and a cupboard 22 are provided, while the space at the rear of the partition forms the filter chamber 14. A drawer 25 is provided beneath a horizontal partition 24 having openings 27 over each of which is superimposed a filter bag 28. When the fan 16 operates, air laden with dragons blood is drawn into the ducting 13 and passes into a collecting compartment constituted by the drawer 25 wherein dust is deposited. The air then makes a sharp turn upwardly, thus causing further precipitation of the dragons blood in the drawer 25. Finally, air is drawn through the walls of the filter-bags 28 formed of fine cotton fabric, leaving any remaining dragons blood on the inside walls. Clean air which passes through the fan 16 is expelled through an exhaust port 31. The filter bags may be supported in a light frame (not shown) slidably mounted such that clinging powder may be shaken from the bags to ensure their efficiency.
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