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Using a ring (regenerative) blower
progen
Top  #1 Print Post
Posted on 09/21/2021 12:30 PM
Has anyone used a ring or regenerative blower for their DIY fluid bed build and can you let me know the specs and batch weight?
 
renatoa
Top  #2 Print Post
Posted on 09/22/2021 1:29 AM
You mean the blower itself, or the air recirculation solution ?

Any full metal turbine blower should be appropriate for this job, if the motor is outside the turbine can, and cooled by an impeller.

From what I read, if the intake air for heater is 70 C degrees, the power required to perform the roast is halved. To have a reference, the air exhausted by my cyclone is 80 C degrees.

Hope it helps.
 
progen
Top  #3 Print Post
Posted on 09/22/2021 3:59 AM
Hi Renatoa, I meant for the loft blower itself.
 
CK
Top  #4 Print Post
Posted on 09/22/2021 1:47 PM
Here's a beauty! Sputnik3.
Fasten your belts and prepare for takeoff.
 
progen
Top  #5 Print Post
Posted on 09/23/2021 2:35 PM
Any idea of that blower's rating?
 
renatoa
Top  #6 Print Post
Posted on 09/23/2021 3:20 PM
Isn't the same as for a cold air unit ?
The fact the air is hot affects the power consumption only, I think... the airflow should be the same, to get same lift...
So the standard FB design guidelines are preserved.
 
CK
Top  #7 Print Post
Posted on 09/23/2021 9:40 PM

Quote

progen wrote:

Any idea of that blower's rating?


Not sure, but it is easily used for their 320 grams charge weight... it was shown running at 18% on the LCD2004 in the bottom video. I think it's always better to over design prototypes because it gives more headroom for experimenting on larger capacities.
 
progen
Top  #8 Print Post
Posted on 09/29/2021 9:05 AM

Quote

CK wrote:

Quote

progen wrote:

Any idea of that blower's rating?


Not sure, but it is easily used for their 320 grams charge weight... it was shown running at 18% on the LCD2004 in the bottom video. I think it's always better to over design prototypes because it gives more headroom for experimenting on larger capacities.


Thanks so much for that. I did manage to contact one of them and the blower was a 750 watt 1hp one. A blower of that rating can be had at around USD160 - 170 in my country. USD70 more if I want it right away because I live within walking distance of two blower specialists.

My aim is to build a 1.2 - 1.5kg green weight roaster so that should be plenty of power.
 
renatoa
Top  #9 Print Post
Posted on 09/29/2021 9:38 AM
I would try first a 500W leaf blower, they are very cheap, less than $20 here.
When attempted to use mine for 500 grams beans cooling the result was a tornado of beans in my whole kitchen... Shock

But... it's hard to find if the blower has metal turbine for these models... so the regen part is under question sign.
 
progen
Top  #10 Print Post
Posted on 10/07/2021 12:42 PM

Quote

renatoa wrote:

I would try first a 500W leaf blower, they are very cheap, less than $20 here.
When attempted to use mine for 500 grams beans cooling the result was a tornado of beans in my whole kitchen... Shock

But... it's hard to find if the blower has metal turbine for these models... so the regen part is under question sign.


Those blowers are even cheaper in my country. Can get a 750w one for USD10. When you used your 500w one, was it on full power?
 
renatoa
Top  #11 Print Post
Posted on 10/07/2021 2:20 PM
The model I tested has a simple on-off button, not a proportional trigger, so yes, at full.
Was just a capability test, immediately after purchase, just unpacked.
 
progen
Top  #12 Print Post
Posted on 10/08/2021 5:43 AM
Thanks for the information, Renatoa. I did look at many of them but decided to spend a bit and get a regenerative blower since it was on sale. 750W 1HP for slightly below USD150 to my doorstep. I was looking at the three phase one actually but with the VFD, it'd have come up closer to USD250 and I already had the inline dimmer so I went with the single phase version instead.
 
CK
Top  #13 Print Post
Posted on 05/02/2022 10:23 AM
Progen, do you have any pictures or videos that you'd like to share of your machine?Grin It would be interesting to see your setup...
 
progen
Top  #14 Print Post
Posted on 07/21/2022 9:22 AM

Quote

CK wrote:

Progen, do you have any pictures or videos that you'd like to share of your machine?Grin It would be interesting to see your setup...


Like most ingrates, I only come here when I need help so I'm sorry I didn't see your post earlier. I've posted some information and links to videos of my build in this thread.

https://homeroast...post_75492
 
fpcf
Top  #15 Print Post
Posted on 01/05/2023 3:48 PM
I like your discussion about recirculation. But I don't like the exhausts in my beans. I'd like to seperate my exhausts through an automobile Intercooler. You will get them cheap in China. Hot air will be blown through the intake of the intercooler and fresh air is heated by the cooling mesh. Does anyone has experience with something like this? I planed to use a sidechannel blower. So hot air intake is not the main problem.
 
renatoa
Top  #16 Print Post
Posted on 01/06/2023 2:02 AM
Be aware that more than 70 C degrees into the heater could shorten the motor life seriously...
 
fpcf
Top  #17 Print Post
Posted on 01/06/2023 4:13 AM
I have a side chanel blower in spare. The motor is seperatate from the blower and has an own fan. Its very powerful so I have to control it carefully. I'm more concerned about the ball bearings inside of the blower chamber? How do they behave when they are heated.
Second question is I don't know anything about the heat transfer of the intercooler? Does this works efficient? I'm really impressed of the Sputnik 3 Projekt of Frans. I only miss recirculation of air for energy saving reasons. There is no connection between exhaust and intake. In modern industrial drumroaster hot exhaust air is mixed with fresh air and recirculated. I don't like this concept because I don't want to have all the fumes on my beans... First I thought about a water heat exchanger for a swimming pool, but they have a small exchange area hence they made for water. So I got the idea to exchange heat with an automobile intercooler. They are made for air and for fast heat exchange. Its relatively cheap and you'll get these in various different sizes.
 
Yasu
Top  #18 Print Post
Posted on 01/06/2023 3:00 PM
I think it is important to consider efficiency in roasting because of energy savings, carbon neutrality, cost, etc.
I have previously calculated how much energy is used per roasting cycle on my roaster (3kg drum roaster).
I did not include a value for preheating because it depends on the number of times the beans are roasted, and I used 1 kg of green beans. The room temperature was 20°C, the roasting was just before 2C, and the drop time was about 14 minutes.
1. LPG gas 70g （0.92kwh）
2. Electricity usage (heater + exhaust fan + drum motor) 0.45kwh

Total 1.37kwh per 1kg (1178 kcal) efficiency.　

I think I can roast 2kg at a time with this device, so I think the efficiency could be better, but I want to roast many times, so...

It would be very helpful if you could share the efficiency of your roasting machines.

By the way, the circulation of the exhaust fan is
100% circulation during preheating (exhaust air is returned to combustion)
During roasting, the flow is 100% discharged to the atmosphere.
 
renatoa
Top  #19 Print Post
Posted on 01/07/2023 1:21 AM
A turbo oven setup looks a lot more efficient...

333 grams with 1300W @ 65% for 10 minutes = 0.42kWh per kg

... am I wrong somewhere ? is three times less Shock

Maybe because turbo oven is total re-circulation... just minimal chaff exhaust, because I don't smell any smoke in beans...
 
Yasu
Top  #20 Print Post
Posted on 01/08/2023 6:36 PM
Mr. renatoa
Thank you for sharing this information.
I now understand that releasing heat to the atmosphere without circulation is inefficient.

With the current system, I think the best I can do is about 0.7 kWh per kg for roasting 2 kg.
I think the efficiency is about 0.7 kWh per kg for roasting 2 kg with the current system.

This year I hope to improve my system a little with roasting efficiency in mind. (insulation, exhaust heat recovery, etc.)
 
ACEMBL
Top  #21 Print Post
Posted on 01/18/2023 11:59 AM
Sorry to be so late to the party on this conversation. I’m playing with a forced air roaster that uses a side channel blower (that’s what they call it in UK), a fairly big 3.3kW air gun element and a my sort of Sivitz inspired chamber.

I have been looking into recirculating some of the heat into the blower and with some advice from a pro and Renatoa’s 80C guidance (made some time ago) have been channeling some back from the cyclone. I’m currently working on a motorised valve idea to manage the exhaust recirculation.

I’d roughly estimate that it’s about 25% more efficient just by ending the exhaust 3 inches from the inlet. With proper control I’m sure it will be even more so.

I
 
fpcf
Top  #22 Print Post
Posted on 01/19/2023 9:54 AM
Thank you ACEMBL that's a great idea to protect the motor of the blower with heat controlling.
Mixing the inlet air from the heat exchanger ( automobile intercooler) with fresh air with a motorized valve to cool it down is really the goal. I already use two motorized valves from an automobile exhaust pipe for bean charge and bean drop.

My main problem is that I don't know the exhaust temperature behind the cyclone chaff collector and how efficient will be an air heat exchanger?
 
ACEMBL
Top  #23 Print Post
Posted on 01/21/2023 3:38 AM
Ooh I like the sound of those motorised exhaust valves. I’ve been thinking about solutions that will handle the hot air out of the cyclone.

I’m going to have a go at making a diverter/valve that will proportion the cold and recirculation air.

Just out of interest would it be worth testing matched roasts with and without recirculation to see if there’s any notable undesirable flavours? If your cyclone is efficient enough at getting rid of small particulates you might not need the inter cooler.
 
fpcf
Top  #24 Print Post
Posted on 01/24/2023 4:50 AM
Hi ACEMBL , the reason for using the intercooler is not to have fumes from the beans in the circulation. I only want to have preheated fresh air passing the beans. So I have to use the intercooler as heat exchanger to separate exhausts from fresh air. Having a motorized valve to control air temperature is pretty cool idea.
 
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