Last week we tested the next version of The Fluid Bed Roaster prototype. Tije designed and constructed this new roaster. In the picture above, you can see him charging green coffee beans on the prototype. The roaster has a build in cooling, chaff collector, LCD screen and it uses a more powerful and less noisy blower. Also the roaster has a higher capacity (batch size) than the previous model. I worked on the Arduino TC4 control board and electronics. In this first test we encountered a technical problem. I got a much cheaper relay to drive the blower of the roaster. This relay blew immediately after powering up the device. We will switch back soon to Crydom 2425-10 relay that has proven to work solid in the previous prototype. For speed control we reverted back to manual Variac operation of the blower. The PID settings to control heater intensity also needed some work and Tije has already worked on a heat isolation of the roast chamber. The purpose of this insulation is to make the roaster more energy efficient and make it easier for the roaster to reach a desired finish temperature.
Testing insulation on the new roaster
After just a little tweaking the roaster already replicates the target curve pretty good. The Artisan software by Marko Luther in combination with the TC4 firmware by Jim Galt (greencardigan) and TC4 hardware is doing a good job again!
Frans Goddijn again made a nice video about our test
You can also read about this project on Frans Goddijn’s blog