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CoffeeAir - 1kg Indoor Electric Roaster Trial

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  • CoffeeAir - 1kg Indoor Electric Roaster Trial

    Hello, CSers!  I come with another labor of love still in progress.

    The concept is an indoor, smokeless, hot-air-recirculating, roaster/cooler/dechaffer, that runs on a 20amp (or less) 120VAC circuit.

    So far the design is revolving around a Kirby Vacuum Cleaner motor.  The motor assembly is all aluminum with an aluminum fan blade plus a "heatslinger" fan to cool the motor.  It is a universal brushed motor whose speed can be continuously varied with a triac timer controller.  This motor lofts 2+ pounds (about 1 Kilo) only drawing 2.55 amps.

    The motor blows up into a section of muffler pipe housing nichrome heater coils, then into a removable roast chamber, part aluminum and part glass to circulate the beans.  The hot air goes up into the back side of the roaster where there is low pressure and aluminum screen to trap the chaff, and the hot air continues on, returning to the motor inlet.  To cool, shut the heat off, then open a panel to allow cool air to enter and blow acoss the beans.

    Fire (smoke) needs oxygen.  My hypothesis is that a self contained, sealed roaster will not smoke, or do so very little.  But since it cant be completely sealed, this will allow moist, hot air a path to escape, while hopefully not bringing any new air in until cooling starts.

    The roaster isnt done yet... so its very possible this wont work, but well see!

    The final construction is with aluminum angle and cement board.

    Ive documented extensively in this thread:
    http://www.homeroasters.org/php/forum/viewthread.php?forum_id=32&thread_id=984&rowstart= 80

    CHAD


  • #2
    Re: 1 Kilo Indoor Electric Roaster Trial

    The motor

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    • #3
      Re: 1 Kilo Indoor Electric Roaster Trial

      The pre-test

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      • #4
        Re: 1 Kilo Indoor Electric Roaster Trial

        The hopper

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        • #5
          Re: 1 Kilo Indoor Electric Roaster Trial

          The heat tube

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          • #6
            Re: 1 Kilo Indoor Electric Roaster Trial

            Motor heater combo

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            • #7
              Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

              The theory

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              • #8
                Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                Hi Chad

                Nice project you have going there!

                In your first note you mention that the hot air returns to the motor inlet but in the drawing it says tha no heated air blows across the motor, so Im a little confused as to which it is?

                Also, if I interpretthe design correctly, the elements will continue to heat the recycled air, thereby increasing the temperature exponentially. If this is correct, do you plan on controlling the temperature by means of introducing fresh air through the process?

                Sorry if these questions are addressed in your extensive documentation as I havent got round to reading that yet.

                Cheers

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                • #9
                  Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                  Originally posted by seedlings link=1220449786/0#0 date=1220449784
                  Fire (smoke) needs oxygen.  My hypothesis is that a self contained, sealed roaster will not smoke, or do so very little.  But since it cant be completely sealed, this will allow moist, hot air a path to escape, while hopefully not bringing any new air in until cooling starts.
                  True, but will this have any effect on the "smoke" which is the vaporized oils from the beans?
                  If the unit is contained, wouldnt the smoke just build up inside and then be released.
                  Think about a drum roaster, they emit a huge cloud of smoke when its opened to dump the beans.

                  If it produces a small enough amount of smoke to be used inside, I would be very interested in making myself one

                  Very nice build by the way! Keep us posted on how it goes

                  Comment


                  • #10
                    Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                    One of the important elements in roasting beans for the best flavour is the amount of air (fresh air) passing through the bean mass.

                    Professional roasters control this airflow very carefully and vary it at different stages of the roast.

                    If the same air is trapped and recirculated.... the oxygen it contains will combine with the oils to produce smoke (until all the oxygen is used up) and this smoke will recirculate through the bean mass....

                    I would imagine you will get a very "smoky" flavoured roast - which you might like..... but in any case I think the flavour will be considerably different to a conventional roaster with airflow - whether that difference is good or bad will be a matter of tasting the resultant brews!

                    Comment


                    • #11
                      Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                      Hello, Dennis, the vacuum motor inlet is directly beneath the motor.  The outlet is to the side of the motor, so the hot air will come in below, and blow out beside the motor.  That will keep the motor out of direct heat.  Now, for sure the heat will travel through the alumimum housing... and theres still no certainty how bad that will be. And as to the air becoming increasingly hotter, the heat element is continuously variable from off to 15 amps, so the intention is for the recirculation to tremendously boost effeciency. Hopefully much lower amperage will be needed.

                      Regarding the smoke... I do realize there is a risk of this not working as well as hoped, but its worth a shot.  As one example, the Behmor is an indoor electric drum roaster designed without fresh air entering.  Granted, the unit is not perfectly sealed, but it is my understanding that there is very little smoke and high praise is widely awarded to the roasted coffee results.

                      No further progress to report.  Rain showers prevent me from opening the garage door for ventilation to cut more cement board.

                      Thanks for your comments!
                      CHAD

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                      • #12
                        Re: CoffeeAir - 1kg Indoor Electric Roaster Trial


                        As always Chad, Im lovin your work.

                        I was surprised that motor will lift a kilo of beans, I would have expected somethig much larger.

                        There is little better than home roasters having a crack at something a little left field and you sir are the master!

                        I look forward to following the progress, thanks for sharing.

                        Andy.

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                        • #13
                          Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                          Thanks, Andy.  This motor lofts over 2 pounds using less than 3 amps (motor rated for 6 amps)!

                          Heres a :10 video

                          http://s206.photobucket.com/albums/bb54/seedlings/?action=view&current=coffee2.flv

                          Thats the "direct link" to the photobucket.com video.  Often the link doesnt work.  go to www.photobucket.com/seedlings and scroll down a little to the 2 videos next to each other.

                          CHAD

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                          • #14
                            Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                            Hi Chad great work. I watched your video it looks like you may need to have a longer bean chamber. As you probably know when the beans get roasting they will jump around more and fly out of the top.

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                            • #15
                              Re: CoffeeAir - 1kg Indoor Electric Roaster Trial

                              Thanks for explaining Chad.

                              Dont let a little rain stop you now - get a gas mask if you have to, cause were looking forward to the next instalment!

                              Cheers

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