Method for roasting coffee beans with hot air comprises separating off two gas streams from exhaust gas, one of which is fed to combustion chamber for heating air, while other is fed through purifier

摘要

Method for roasting coffee beans with hot air comprises separating off two gas streams from the exhaust gas. One of these is fed to the combustion chamber for heating new processing air, while the other is fed through an exhaust gas purifier. An Independent claim is included for apparatus for carrying out the method comprising a roasting chamber, an air heater (5) fitted with a burner (7), a centrifuge, ventilator, exhaust gas purifier and pipes linking them. A by-pass system (11) is fitted on the combustion chamber of the air heater, downstream from the exhaust gas inlet, which surrounds it and forms a channel for hot gas which is separate from that feeding the exhaust gas purifier. Two control valves (13) are fitted for the by-pass and processing air streams.