Consisting of two main sections, the machine would demonstrate the process of roasting the coffee beans, as well as the extraction process. Within the roasting section, green coffee beans are roasted using a fluidised bed reactor, which utilises a cyclone and heat exchanger for separating silver skins. Whereas, the extracting section makes use of a grinder, a heating tank with an immersion heater, a suspension tank and a filtration device.
The process begins by dosing green coffee beans through a screw conveyor. The beans are then roasted in the fluidised bed reactor with the help of a fan and air heater. As the beans are being roasted, water from a tank is pumped through the reactor’s heat exchanger tube to preheat it. The roasted beans are transported to the mill using a bean lift, where they are then grinded into coffee grounds. The preheated water is further heated in the heating tank and sprayed onto the ground coffee using a spray head. Finally, the suspension is filtered, leaving coffee.
For the project, Norelem provided swivel castors with a locking system and robust tubular handles which were installed to allow for easy transportation and parking of the machine. Cheese head screws and other standard components were also used to assemble the fluidised bed reactor.
To transport the beans to the mill, a toothed belt shaft and stepper motor were used, and a housing bearing unit was employed to both mount the toothed belt pulley and tension the toothed belt. Norelem also supplied maintenance-free housing bearings and a precision shaft controlled by the stepper motor to support the load-bearing rotating plate on which the finished coffee was served. Finally, rubber buffers were used to minimise vibrations, while cover profiles were used to protect the system from dirt, dust and coffee spills.
