Retail coffee bean roaster has double-walled glass vessel acting as heat exchanger to achieve close thermal control of quasi-continuous batch production

摘要

A small-scale coffee bean roaster discharges hot air downwards through a heat exchanger which pre-heats incoming cold air prior to its passage through a heater. The quantity of pre-heated air returned is controlled by a regulating valve (21). The roaster unit has a double-walled cylindrical glass chamber (1) with a cylindrical and a conical section. The chamber also serves as a heat exchanger with a spiral air inlet and a tangential outlet. The cylinder has a centrally located hot air pipe (8) discharging into the cylinder base and creating a rotational fluidized flow pattern roasting bed. The heat exchanger is a double-mantled gas cyclone (9). The upright cylindrical glass roasting chamber is detachable from the unit. The chamber has a top-end closure with a central removable hot air inlet tube, a coffee bean inlet and closure, and a hinged base discharge outlet cover. The closures are clamp-protected.