Initial Airflow Testing

2011 December 31
by Joe Johnston

With the holiday season, our pace of development slowed a bit. Even so, we were able to perform our initial airflow testing. We cobbled together a very effective test jig using a Dayton blower, ductwork fabricated by local metalworking company: Typhan, and a hydraulic table.

We assembled the test jig in a garage in Agritopia┬« and began our initial testing. First of all, we lined up the output duct over the center of the bowl. The duct size is 8″ diameter, which is a very common size in the HVAC industry.

We then started the Dayton blower. Driven by a 3/4 HP electric motor, it can deliver up to 1600 CFM. By means of diverter valves, we are able to throttle the output of the blower.

We then ran the prototype with a full batch of roasted coffee at our standard 90RPM while observing its behavior. We adjusted the airflow from zero to full output. It was clear that any higher output would be too much.

Our next step will be to add airflow and pressure sensors in the ductwork to be able to quantify the airspeed and total airflow.

Happy New Years!


4 Responses
  1. January 5, 2012

    I just found your website (and roaster project tonight) and have spent the last hour totally engrossed! First, thank you for openly documenting the creation project and journey…and as you say for “pushing the envelope” in what a roaster can be. I have a lot of questions (curious ones) but have much more to read that will likely answer them.

    • January 20, 2012

      Thanks for taking the time to read the blog. We are enjoying the design process. Feel free to make suggestions and comments at any time.

  2. January 7, 2012

    Everything is very open and very clear explanation of issues. was truly information. Your website is very useful. Thanks for sharing.

  3. January 15, 2012

    Like the blog

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