| 摘要 |
1358039 Tea drying MARSHALLS TEA MACHINERY CO Ltd 6 Aug 1971 [7 Aug 1790] 38142/70 Heading F4G To enable high rates of flow of heated drying air to be used in a tea drier, the air is directed in a single pass downwards on to tea leaves supported on an air pervious conveyer surface. An inlet fan is provided at the top of upper hood 1a and an extractor fan is provided at the bottom of the lower hood 1b. Tea leaf is introduced at 2 and deposited on perforated conveyer trays 10 pivoted at their front ends to two parallel endless chains 11 and maintained parallel to the chains by supports. A rotating paddle 13 spreads the leaves into a bed of uniform thickness which can be adjusted. As each tray 10 passes around drive sprocket 12a, it pivots outwardly to discharge tea leaves through an outlet 3. Each tray knocks against a hammer 17, is rotated back parallel with the chains 11 and passes a scraper 18 and a rotating brush 19. Each tray 10 is allowed to pivot downwards just before the sprocket 12b to discharge any leaves that have fallen through the upper flight. Pivoted baffles 22, 23 and 25 and felt seals 24, 26 prevent the escape of hot air. The inlet air is heated (to 320-340‹ F.) in a tubular heat exchanger (following the inlet fan) by means of heated oil, and the over-pressure and under-pressure in the upper and lower hoods respectively are between 0À02 and 0À10 inches of water. Two or more driers may be used in series, or one may feed a chamber drier. |
