My cyclone project

[edtbjon]

I've been experimenting (for the third time now...) with a cyclone. I thought that I'd start up with a simple chinese plastic one until I got it all sorted. (... and whether or not it was worth the effort ...)
A bit of history: The first one I saw (for the Huky) was the one Susan posted years ago. I tried a similar setup with the original fan and exhaust bowl upside down on top and found it very top-heavy. The "top heavyness" was my biggest concern at the time so I got me an (about) 8"/200mm large radial fan, which sat nicely on the top of the roaster. Now, a radial fan is by nature very effective, so I had from about 30% up to 40% on my Variac to control the fan from standing still to actually sucking all the beans out of the roaster. I abandoned the project for a while, using the standard exhaust setup instead.
But a few months ago, I started to look for smaller fans (mostly in terms of CFM), but also to be able to run a cheap adjustable 0-12V or 0-24V converter instead of the bulky and heavy Variac (clone) that I used.
I bought a couple of cheap fans (in the $10-$20 range) from China (AliExpress) which arrived after a few weeks. The least effective one has a capacity of about 30CFM, while the stronger one is about 60CFM. These fans are about 4" in diameter. Yes, I know they look small, but the stronger fan of the two sucks beans out of the roaster if at full whack!
I use a J type setup, with a depicted "special order" exhaust pipe, which was available for the J-type roaster. For the T-model you can easily get a piece of "blank pipe" from Mr Li. 150mm/6" will do nicely.

As you can see all of the cyclone and chaff bucket is PVC plastic. Yes, it will stand up to the heat as the temperature is below 60C/140F when it reaches the cyclone. But this is an experiment rig and I'd absolutely recommend getting a metal cyclone and bucket for the "finished product"... The duct from the roaster to the cyclone is a generic automotive heat duct, while the outlet from the cyclone is a standard 4"/100mm ventilation flexible duct. ... and yes, I have a fire extinguisher and water nearby.

Last but not least, I'm still not satisfied with the fan selection. 30CFM for this setup is too little, while 60CFM is too much. The problem is that the fans are a bit hard to control (the 60CFM that is...), with very little voltage to play with. I either have to get me a better controller or try to find a suitable 45CFM fan. It's also my opinion that Duct Tape may come in handy while in the experimenting phase...

[edtbjon]

A couple of more pictures...

[monkey_lever]

I have the same plastic cyclone.

Two comments:

- The plastic bucket is a good choice . I haven't had any problems whit it. I liked because you can see the chaff falling just before first crack.

- The weak point of the system is the  vertical section of the plastic cyclone.  The part where you connect the exhaust fan. Mine is completely melted on the inside. I think that when you use low or no airflow the temperature increases and  melt the plastic. Im trying to replace that section with a metal tube.

- Im still using the original fan and my concern is the stability of the setup I used thermal silicone to glue everything up.

Regards.

[SusanJoM]

My two primary reasons for abandoning this rickety set up were similar to those mentioned.   Finding useful non melting connectors and the constant thread of having the whole mess come tumbling down. 

[edtbjon]

Susan and monkey-lever: The difference in our setups is that I use about 3 feet (1 meter) of ducting (60mm/2 1/4" generic automotive heater ducting) between the roaster and the cyclone (as compared to Susans 4" silicon ducting). The exhausts cool very quickly in a few feet of ducting, which seems to be the reason for me not having heat issues.

[brew]

I've been thinking of making a collector.  I'm not even sure if something like this or similar would work.  Thoughts?

[SusanJoM]

What exhaust tube do you have Tony?
Note that the one in the picture above was designed specifically for using with a cyclone....

[brew]

I don't have one and the drawing is just a concept.  I would probably use initially some type of pvc setup with some flexible tubing length connecting it as ebtjohn has done.

[edtbjon]

I don't have one and the drawing is just a concept.  I would probably use initially some type of pvc setup with some flexible tubing length connecting it as ebtjohn has done.

You can possibly make something similar work if you apply the cyclone "principle" to it. I.e you make the inlet spin through a cone into a bucket and sucking the outlet out through the top. Else, because the chaff is very lightweight, you will probably have a lot of chaff in your outlet of your device.
It seems like the construction of the cyclone presses whatever dust (in this case, "chaff") down, which is the brilliant idea of the cyclone.

[brew]

Yeah...i think that if the inlet from roaster came in at an angle it could work.

[beananimal]

The least effective one has a capacity of about 30CFM, while the stronger one is about 60CFM. These fans are about 4" in diameter. Yes, I know they look small, but the stronger fan of the two sucks beans out of the roaster if at full whack!

With this experience and comparison, can you confirm that the original Huky fan is around 20 cfm?
In my test series it lasted at full power about 12 seconds to blow up 120 liter bag, which is ~10 liter per second and should be ~20 cfm.

[edtbjon]

The least effective one has a capacity of about 30CFM, while the stronger one is about 60CFM. These fans are about 4" in diameter. Yes, I know they look small, but the stronger fan of the two sucks beans out of the roaster if at full whack!

With this experience and comparison, can you confirm that the original Huky fan is around 20 cfm?
In my test series it lasted at full power about 12 seconds to blow up 120 liter bag, which is ~10 liter per second and should be ~20 cfm.

There's a current thread over at HomeBarista on how much more effective centrifugal fans are compared to axial fans, something that I reported on above too.
But... the stock fan is rated at 230 CFM (390 m3h)!!! (Here's a link to a thread about most of the Huky specs and parts. You will find a link to the fan manufacturer in there...)
Now, even though that first setup with a stock fan and exhaust bowl upside down on top of the cyclone was a little bit overpowered, the difference between the two fan types is really spectacular.
The first centrifugal fan which I bought for the cyclone was an AC fan (as I already had a Variac at hand) rated at a similar airflow (about 250CFM). That fan was extremely hard to control, with a span of say 10V on my Variac from "not spinning at all" to "almost full blast". It was also way too powerful, which is why I'm going for these smaller fans.

[brew]

You can possibly make something similar work if you apply the cyclone "principle" to it. I.e you make the inlet spin through a cone into a bucket and sucking the outlet out through the top. Else, because the chaff is very lightweight, you will probably have a lot of chaff in your outlet of your device.
It seems like the construction of the cyclone presses whatever dust (in this case, "chaff") down, which is the brilliant idea of the cyclone.

I think if I find some 2.5" flexible tubing that can stand the exhaust heat (at least 3' long) i can make it work. 


So assuming I build something air tight and use the same fan with controller, I would be moving the same amount of air.  I've never used a collector of any sorts.  I'm assuming the response time would be slower for the vacuum effect to start?

[Brewzologist]

Just FYI at this point, but I will follow up later with my testing of temperatures and anemometer results, and whether I had to scrap the whole thing!  I am attempting this based on tests by others reporting a 150 degF max. exhaust temp from the stock bowl.  I too will have a fire extinguisher nearby just in case...

I'm currently building a custom cart for my Huky, which will include a simple chaff collector that will sit beneath the surface of the cart top.  The collector is made from wood with aluminum lining using 500 degF caulk and 1000 degF flue tape to seal it.  The exhaust extension is a 15 inch piece of 1.5 inch metal drain pipe that will pass up thru the surface of the cart top and connect to the Huky's T-pipe via a slip coupling.  My fan is a 24 VDC PWM axial fan with plastic blades rated at 250 CFM which is controlled by an Arduino via Artisan, which will send the exhaust outside via flexible ducting. I will mount one of my sieves inside the collector to prevent chaff from getting into the fan blades.  A chaff tray will be at the bottom of the collector and I'll experiment putting a small amount of water in it to help trap the chaff.  This certainly won't be as efficient as a cyclone at collecting chaff, but I'm not production roasting and I like the cleaner layout vs. the cyclone 'stack'.

If the airflow is sufficient but temps are higher than I'd like, I may test adding a small air inlet in the exhaust tube to purposefully allow some room air to enter the exhaust stream to cool the chaff collector.  Given sufficient CFM headroom from the fan, this may be a way to cool the exhaust system without compromising airflow through the Huky.  I was also reading that introducing some leaks in the exhaust may actually help overall flow by reducing the chance of the fan blades stalling.  But this is just a theory right now.. Stay tuned..

Steve

[beananimal]

Hello Björn,
thank you for the link and information.
For me it seems that some puzzle parts are going together.

If a 60 cfm radial fan is much stronger in the system, than a 230 cfm axial fan, than this is due to more pressure / force.
For the flat axial fan I expect a high air flow with not so much pressure.

If just the difference between perforated drum and solid drum causes drop of air flow with the original fan by a factor of 2,
then the resitence of the whole system (bowl, funnel, J-pipe, front-plate-elbow, drum, 2,5" exhaust ) can probably drop the air flow by a factor of 10. (20 cfm instead of 230).
The radial fan is probably more robust on this. (I still have to read the HB thread.)