topbanner.gif
Login
Username

Password




Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
Shoutbox
You must login to post a message.

renatoa
02/07/2023 10:28 AM
Snidely Whiplash, welcome !

renatoa
02/06/2023 10:36 AM
welcome to forum , ETomczak and annguyen20

renatoa
02/04/2023 1:40 PM
Welcome, ediblemanager

allenb
02/02/2023 4:22 PM
bcoffeedrinker Welcome

renatoa
01/31/2023 1:17 AM
pouringZabbaskeema

In Memory Of Ginny
Donations

Latest Donations
dmccallum - 10.00
JackH - 25.00
snwcmpr - 10.00
Anonymous - 2.00
Anonymous - 5.00
Users Online
Guests Online: 12

Members Online: 0

Total Members: 7,792
Newest Member: Snidely Whiplash

View Thread

Who is here? 1 guest(s)
 Print Thread
Brewer to Roaster..blower question...
oldgearhead
Year Four

Recently I?ve been looking into the basics of my unique, 120V, 15A, heat-reclaiming, 500g, fluid-bed, coffee roaster. I?ve know for quite some time that this roaster works well, but I wasn?t exactly sure why. For the first couple of years I:
1) Kept trying to perfect my baffle chaff collector.
2) Struggled to settle on a repeatable bean-mass- temperature system.
3) Adjusted the air temperature three to four times during each roast.

I completely abandoned all that a little over two years ago.

1) Chaff collection - A simple 40 mesh sink strainer from Lowe?s or Wal-Mart keeps all the chaff in the RC until after cooling. Then the chaff is simply vacuumed off the top of the beans.
2) BMT - Not Necessary at all because I?ve mapped the relationship between flow rate and the process variable air temperature.
3) PID - Was a total waste of time for me. I use the T@CFM information to pre-select the roast wattage based on bean type and bean percent moisture content.
4) RoR ? Rate of rise is controlled by two things: the air flow and the ever advancing heat-reclaiming system.

Summary:
A) Reliability ? No failures of any component during the past four years.
B) If the 1550 watt heating element I use is capable of 1000?F at 23 CFM (Master Appliance claim), what temperature can be expected during an average roast? In my roaster the CFM is at 58-64 during the first three minutes and 35-40 during the last three minutes. So let?s map that range with no beans. I use a heater wattage setting of 1175 (75% of the heater?s current wattage of 1565) because that?s the setting I?m using for 500 gram loads of Daterrra Sweet Blue I?m roasting this week. The real-time roast adjustments are made with only the blower control.
oldgearhead attached the following image:
image1-1.jpg

No oil on my beans...
 
oldgearhead
FIVE YEARS!

The only failure my 120 volt, 1550 watt, heat reclaiming, fluid-bed roaster experienced was one 120 mesh screen. Probably too much hard brushing.
Today, in a temperature of 32?C (89.6?F) I used only 977 watts each to roast two 440 gram batches.
oldgearhead attached the following image:
dsc_8593_2.jpg

No oil on my beans...
 
Rostikalsongen
Hello,

I really like the design of your roaster, looks very professional.

Like you, I want to build a roaster for a half, maybe one kilo and make it heat reclaiming.


The one thing holding me back so far would be what kind of fan that could handle these temps, and then I ran into this thread where it seems that you use a standard air pump AND run the hot air through PVC pipe.

Is this correct? How does that compute?
 
seedlings

Quote

Rostikalsongen wrote:

Hello,

I really like the design of your roaster, looks very professional.

Like you, I want to build a roaster for a half, maybe one kilo and make it heat reclaiming.


The one thing holding me back so far would be what kind of fan that could handle these temps, and then I ran into this thread where it seems that you use a standard air pump AND run the hot air through PVC pipe.

Is this correct? How does that compute?


Well you'll have to study up on venturi effect!!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
oldgearhead
Been roasting two or three times per week for five years with no failures except one, used, 120 mesh, input screen. The PVC pipe has worked well I run it between 120-150 DF (I don't let it get above 150 DF).

I don't adjust the roast temperature during a roast, only the air flow and I set the temperature at a certain percentage of the 1550 watt heater, based on the ambient temperature.

It does run close 30 amps when using a DC drive for speed control but about 24 amps with the Variac.
It's circuit is 120 volts/40 anp with 10 gauge wire. It would run fine of a normal 120V/20 amp circuit if I has a smaller, say 1000-1200 watt heater. It is kind of nice to be able to roast in 20 DF ambient though, but not fun..

Edited by oldgearhead on 09/02/2016 8:17 AM
No oil on my beans...
 
oldgearhead
The vac motor used is a standard two-stage, flow-through, 120V spa/vacuum blower, Crossed drilled between blower and heater to keep the motor RPMs up a bit for more cooling. It was used on a Sundance spa before I got it and it's still running fine.The Sundance boots are very hard to find.
No oil on my beans...
 
Rostikalsongen

Quote

seedlings wrote:

Quote

Rostikalsongen wrote:

Hello,

I really like the design of your roaster, looks very professional.

Like you, I want to build a roaster for a half, maybe one kilo and make it heat reclaiming.


The one thing holding me back so far would be what kind of fan that could handle these temps, and then I ran into this thread where it seems that you use a standard air pump AND run the hot air through PVC pipe.

Is this correct? How does that compute?


Well you'll have to study up on venturi effect!!

CHAD


Absolutely fabulous knowledge learned there, especially since my work involves how air flows and behaves, very interesting.

Although, I can?t relate to how the temp would drop if there is a constricted part of the tubing system, or do you mean that the fan somehow decreases the temp?

Help me understand this magic!
 
oldgearhead
I use venturi effect only for moving the roasted beans to the storage vessel using a 'J' tube very simple.

The heat available in an electric heat gun element is inversely affected by the air flowing through it. Example: my heat gun element is capable of 1000 DF, but that is at 23 CFM. I know that 23 CFM is not enough to move a half- kilo of green beans located in a Bake-A-Round but 60 CFM is and 40 CFM is enough for roasted beans. So profiles can easily be managed by varying the blower speed throughout the roast..

My roaster can easily roast half-kilo loads of washed green beans. However, it has difficulty with some dry-processed beans at half-kilo. Because of this and the limitation of the volume of a Mason jar I usually roast 420-440 gram loads...
No oil on my beans...
 
walt_in_hawaii
Thanks, OGH. Is the limitation on your 500 gram load on the heat element or on the ability of the blower to loft the beans? How close to the maximum are you pushing your blower when beans are green? I think I have the same bake-a-round cylinder as you; I'm shopping for a blower (hope you don't mind if I borrow some of your ideas) and I think yours was 1.5hp? So if your 1.5hp is close to maxing out at 500 grams, that's good enough for me, I don't think I would ever go bigger than about 400g. (current load is 200g in my P1).

I'm curious about the 'pipe' that was mentioned I think by Roaster Rob. He had mentioned fooling around by sticking a pipe down into the bean mass over the vent; did anyone followup by making a design that incorporates this idea? seems like you could get a smaller blower to move more beans this way... IF you already have enough heat for the beans.

However, it kinda makes sense... seems the blower air energy is dissipating rapidly once it clears the screen and probably vents outward in a cone shape, but as the force is strongest near the center column, that's all you actually see; a small fountain in the middle if its a symmetric center design like yours. Confining it using a tube hovering over the screen confines the force coming out of the screen and doesn't allow it to dissipate, so it forces the beans higher. This would be a way to increase the efficiency or move more beans with a smaller blower, sort of a ducted fan effect (lets call it ducted blower). But, its useless if you don't have enough heat for that bean mass. Thus my question.
aloha,
walt
 
oldgearhead
My limitation with a Bake-A-Round is not the power of the blower (vac motor), but in the tube cooling after the roast is finished. The beans expand quite a bit during roasting and I don't have enough room in the tube to cool much more than 500 grams at high blower speed. Also a Mason jar will only hold 420 grams of washed beans and 450 grams of decaf beans. Some, not all, dry processed beans shed so much chaff that I am limited to a smaller (350 grams) loads.

Remember my manifold is cross-drilled between the blower and the heater. Cross-drilling raises the RPM of the blower to help keep it cool.
Remember also I have feed this used blower 120-150?F intake air for almost six years..They are very good blower/motors..

No oil on my beans...
 
oldgearhead
The device that I use to transfer the roasted beans from the Bake-A-Round to a Mason jar has a 2.00 inch inlet to the shop vac , a 1.25 inch pick-up and a tee.. The tee fits a Mason jar.
oldgearhead attached the following image:
dsc_4334_3.jpg

No oil on my beans...
 
Jump to Forum:

Similar Threads

Thread Forum Replies Last Post
Bellwether Roaster Drum Roaster (Store Bought and Commercial) 17 02/01/2023 8:12 PM
Android App: Coffee Roaster Free ROASTING SOFTWARE APPS 2 01/30/2023 10:32 AM
Using a ring (regenerative) blower Fluidbed Roaster 24 01/24/2023 4:50 AM
"Well tempered roaster" more feedback Roasting Coffee 34 01/20/2023 2:30 AM
HearthWare Roaster Value? JAVA TRADING COMPANY 8 12/28/2022 7:17 AM
Homeroasters Association Logo, and all Content, Images, and Icons © 2005-2016 Homeroasters Association - Logos are the property of their respective owners.
Powered by PHP-Fusion Copyright © 2023 PHP-Fusion Inc
Released as free software without warranties under GNU Affero GPL v3
Designed with by NetriX
Hosted by skpacman