| 摘要 |
<p>Coffee is roasted continuously by (a) charging green coffee beans to one end of a rotating perforated cylinder that is divided into compartments by a helical screw along its length; (b) rotating the cylinder to advance the beans so that they pass through the cylinder in 2-10 min.; (c) simultaneously blowing gas heated at 200-240 deg.C upwards through the cylinder along its entire length, at 670-1250 m/min and weight ratio gas:coffee 40:1 to 150:1, so that the coffee is maintained in a bubbling bed in each compartment; the bubbling bed is intermediate between a static non-fluid bed and a fluidised bed, the greater proportion but not all of the beans being suspended in the roasting atmosphere; and (d) withdrawing roasted coffee at the other end of the cylinder.</p> |
