Well, it’s not that bad at all ! The inline fan looks good. Perhaps you could install a simple filter. My former fan broke down because it was congested with coffee oil.
1 Like
Topic Controls
Blockquote
My former fan broke down because it was congested with coffee oil.
Uh-oh… I thought you were concerned about chaff! Guess I’d better get something in front of the fan.
Bruce
Here is my setup.
The exhaust divided, one for the roaster and the other to speed up the cooling process.
8 Likes
Nice solution.
There’s another issue with the cooling tray which your implementation addresses. Without something to grab the cooling tray exhaust, there’s a white residue which collects on the bottom of the Bullet. Dunno if that residue/smoke/dust (??) gets to the components but what you’re doing should keep that from happening. (I wonder if it might help keep the IBTS clean?!)
Bruce
3 Likes
Curious about your set up and the guidance of keeping the exhaust less than 1-2 meters. I am designing a similar system where I’ll have the hood above the roaster connected to duct fan using about 2 feet of duct. I’ll then need additional duct from the fan to the exterior wall but this length is probably another 3 feet. What is the overall length of your exhaust solution? and do you know if the 1-2 meter (big range there) guidance is for the entire exhaust solution of just from the roaster to the fan?
Many thanks.
The Aillio limitation of 1-2 m was for an unpowered exhaust duct attached directly to the Bullet. Preferably that duct was to be straight (no elbows or bends). I have misgivings about a passive duct like this because of air drag in the duct as exhaust moves to the outside and because air pressure differences between the building interior and the exterior ambient pressure will directly affect air flow thru the Bullet. Make-up air for the room is critical for a passive system in order that the Bullet exhaust fan can operate unaffected. In addition, air movement outside the building can affect the passive flow rate. Now comes too much info…
An alternate is to add in-line, powered air movement with enough flow rate and connect that powered exhaust duct directly to the Bullet. In this case you run the risk of the external exhaust affecting the flow rate of cooling air thru the Bullet. Anything that alters the air pressure at the Bullet exhaust vs. the air pressure at the Bullet air inlet (lower rear of the Bullet) affects air flow thru the Bullet and consequentially alters the air flow for a specific F#. That essentially overrides the Bullet’s exhaust fan.
However, if you leave a gap between the Bullet exhaust and that powered ducting (the range hood you plan to use is a great example), the external system can sweep the air space without affecting air flow thru the Bullet because air pressure at the Bullet inlet is (probably) equal to air pressure near the Bullet outlet. Under these conditions the duct length can be whatever it takes to get to the outside to the extent the flow rate is high enough to move contaminants outside before they condense or attach to the inside of the ducting. @bertje1959 (above) suggests a filter to collect the contaminants which is a great idea.
Assuming you have a source of make-up air like an open window or door, a powered external exhaust system (range hood or a purpose-designed exhaust system) can keep the air fairly clean (it’s not perfect!) without affecting Bullet roasting profiles. Just keep in mind that after you shut off the roaster, oils inside the drum and the exhaust will evaporate and cling to everything in an enclosed space. That’s a vote for keeping the exhaust system running longer than just while you roast.
Also, an air-gap connection is the current recommendation from Aillio.
Bruce
3 Likes
Here is my second evolution of an overly complicated exhaust. The inline fan is the Cloud S6 that so far I have only ran at half speed (there are 8 settings) and the cone has a filter material that seem so far to be doing an exultant job, no residue seems so far to get beyond the filter. There is a 6in gap between the end of the exhaust from the Aillio into the cone and the filter at the neck of the cone.
2 Likes
4 Likes
Yes! This looks good. What is the fan you’re using pls? And have you put a filter in the hood neck?
Black Stripe roasts a lot of coffee (Dashboard → Users → Search ). Makes the installation very credible.
A couple things to keep in mind-
- Current Aillio guidance recommends an air gap between the roaster and the fan-driven vent line so that the exhaust fan isn’t defeated (especially at low settings) by an in-line fan.
- It never shows up in installation photos, but there has to be a source of make-up air when venting to the outside of a closed space in order to not create a low pressure area around the roaster. In a really well-sealed building the roaster will be throttled for air which will affect exhaust fan flow rate.
- I see they gathered the cooling tray exhaust too. If you do that (seems like a good idea!) you probably need to provide a fan to move a little air under the roaster since the cooling tray provides that function- even when not cooling, that fan is running at maybe C2.
Bruce
Edit- when I commented on cooling tray exhaust in Apr 2020 I didn’t know the cooling tray fan was kept spinning at low speed to provide air movement under the roaster.
2 Likes
Thank you bab, for verifying Black Stripe’s setup. I’m thinking that a cooker hood with 380m3/he might be a good idea… 
I’ve been given a 4” inline fan, tho flow rate is only 53m3/hr - what’s the flow rate of the Bullet’s fan at F9?
The make-up air also makes perfect sense - I’ll look into that some more.
No clue! Calibration is in rpm only with no equivalent flow rate mentioned I’m aware of.
Bruce
1 Like
My range hood has 3 speeds: 300/510/680 cfm (500/860/1160 m3/hr). I use low speed during preheating, and have also roasted at low but then the kitchen smells of coffee a bit. Medium speed is perfect. Don’t need high speed, at least not up to the first snaps of SC.
I don’t use any ducting. I roast up to 450g batches, and the most I’ve ever done in one session is two batches. Hope that helps!
2 Likes
Bradm, that sounds exactly what I’m looking for. That’s quite a high flow at over 1100 M3/hr - What manufacturer number is the hood pls?
@bradm’s setup is also my planned setup. My range hood is up to 900 CFM in 6 different speed settings. Good to know that at 510 cfm setting that worked well.
@Scott_Waugh my range hood is this one: https://www.homedepot.com/p/Cavaliere-30-in-Convertible-Range-Hood-in-Stainless-Steel-SV218Z-30/205896803
1 Like
I’m in the planning stages for a basic venting solution (I haven’t even unboxed my R1 yet!). Any advise on a filter material to place in front of the in-line fan? I don’t want to kill too much of the air flow, but also don’t want to ruin the fan by gunking it up.
@forrey45 What filter material to do you use in your hood?
Thanks! Ben
1 Like
See note #10 above (@bertje1959) - hard plumbing plus a box to hold the same filter material as the cooling tray for easy maintenance. Very nice setup.
Bruce
I know it is strange but I found in home depot 12 Inch by 18 Inch by 1" Thick Floor Pads white for polishing, they fit on the bottom of a sanding machine. I just cut them to size and they have worked very well for me.
2 Likes
I actually managed to get my Bullet set up in a good spot in the kitchen and working well with a direct (unpowered) vent. I printed the exhaust adapter in nylon and connected directly to rigid 3" duct, which vents directly outside through much less than one meter of total length with a single 90, and a commercial Seiho vent cover. The Aillio flows so little air even at the highest fan setting that flow doesn’t seem to be a problem, and there is a window only a meter or so away that I can crack for make up air at the same pressure. (I have forgotten to open it a couple times and didn’t notice a difference, however.) I’ve done a lot of overlay and playback roasts with the same beans over many days, and see no significant variation with wind/weather/furnace running/wood burning stove operating - variation in preheat at the time of Charge is a much bigger factor. I think a directly connected vent can work just fine under these conditions: short enough and close to a window that can be cracked to short circuit any pressure differential across the roaster. I have roasted on some windy days, but I suspect if it were windy enough - like a major storm or wind event - I might be able to observe some effect of that. Up here in in the hills above Silicon Valley, we do get some serious wind from time to time - 40-60+ mph gusts - and I’ll probably avoid roasting if it’s really blowing.
2 Likes