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wet scrubber
desperate coffee lover
I was wondering if any of you did build an effective and quiet wet scrubber out of comodity parts.
My goal is to completely eliminate roast fumes and smells so I can continue homeroasting without annoying anyone.

If you succeded, can you tell me what kind of pump and spay head did you use.

Thanks everyone and happy roasting!
 
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seedlings
I'm not sure what you mean by "wet scrubber"? It may be a Canadian-American english slang thing that I don't understand.

It sounds fun, though.
CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
desperate coffee lover
You can look on wikipedia for wet scrubber.
It is basically a device that take air pollution and turn it into water pollution. Not ideal, but sometimes more acceptable.
I hope I can put one together with an aquarium pump, a bucket, a shower head , some plastic tubing and a venting hood. I just don't know how fine a mist is required and how strong a pump to drive it.
 
seedlings
Oh, one of T H O S E things. I understand now, and would very much like to roast indoors smoke free, so please keep us up to date on your findings!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
desperate coffee lover
Real wet scrubber are too complex for me to build.
Can anyone tell me if any of these two rough scetch is a good candidate for an effective air filtration.

Thanks everyone and happy roasting!
desperate coffee lover attached the following image:
wet scrubber2[962].jpg

Edited by David on 05/30/2008 2:05 AM
 
Dan
I've heard them called simply 'scrubber', the wet is implied. I don't understand the top left design, but the bottom left is self-evident. Remember, the deeper the water the more suction the vac has to have to pump the air that far under water. Vaccums are rated in inches of water suction and that refers to this depth.

Have you heard of Rainbow vacuum sweepers? They use a water bath as filter. There water is only about 2" deep.
 
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Brainiac
Hi "desperate"

Here's a simple method I have played with.

For "low pressure misting nozzle" think "garden watering system micro-nozzle" - lots of different spray patterns available.

This can be easily constructed out of 2- and 4-inch PVC plumbing bits

Test it in the sink - use the water-filter adaptor faucet and hose, and drain the (dirty) water directly (or else you will need a pump and filter)

Brian
Brainiac attached the following image:
scrubber[961].jpg
 
Dan
Brian, If you designed that just right, you could eliminate the blower motor (and the likelihood of water getting in your blower and motor).

Use the water spray to induce a draft to draw smoke from the roaster.

I've made two such devices as a ventilator for acid funes. The acid would destroy a blower. I use a blower to induce a draft in a venturi made of all plastic parts. These devices are called inductors. Dan
 
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dBndbit
Desperate,

Great topic and discussion! This could be a very practical solution to our persistent anti-social gas problem. I've started putting together a bigger roaster for home use, so smoke and smell are a primary concern. They're aren't many other practical options. A useful afterburner can burn a lot of natural gas to clean a little un-natural gas. While a scrubber offers the benefit of also cooling the vent gas so all we would need to run through a blower or shop vac would be cool high-humidity air.

This is asking a lot, but can anybody (Brian? Dan?) offer some numbers on absorption rates in sprayers and bubblers based on the out-gassing of green beans by weight? Is there a way to guess a practical height for Brian's vertical fog tube or a bubbler? And what's the (numerical) difference in absorption between the two, one better than the other? Intuitively, we would probably do better with very tiny holes in the bubbler tube and/or a very fine sprayer. And the heat of the exit air should help vaporize the water.

FYI, I recently ran a vacuum test on my mid-sized shop vac using the classic vertical-plastic-tube-in-a-bucket suck test. It pulled 49.5" of water, very close to it's spec. That sounds like it would be a significant height for a bubbler. Would some agitation in the water help keep the bubble size small?


Jim
11 years old... forever!
ReeferDoor.com
>home-built roasters and fair trade
 
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Dan
Jim, Good observation on the temperature and humidity of the scrubbed air. A wet-or-dry shop vac should be able to handle that with ease.

I have no idea how much water mist/splash you would need.

Just because your shopvac pulls 50" doesn't mean you need a 50" water column. It just that you don't want a 60" water column. The small blower Brian pictured only have 3-6" of suction, so this is critical for them, but not for a shop vac with vacuum motor.

The Rainbow sweeper has about the same type of motor as your shop vac. But, it only uses a 2" deep bath. What it does is suck the water up into a domed container where it splashes back down. This constant splashing creates an everchanging serpentine path for the air, trapping the smoke particles.

More later, the grandson came in!
 
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desperate coffee lover
Sorry for the long delay but i had to try a few things before i finally got something that works. I first tried to build a filter out out of plastic see-trough dry food container. it was nice to see how it behave ,but unfortunately was not strong enough. So i build a tougher one out of used cat litter container. It is quite effective in its actual form but still needs improvements and i am not sure where to go from here, i am going to give it some time. see the pictures of the filter and dirty water. please comment on ways to improve it.
desperate coffee lover attached the following image:
ws-dirty-water[995].jpg
 
desperate coffee lover
the filter assy is composed of two cat litter container. the bottom one is unmodifided (not shonw in this picture) the top one is pierced so a pipe actually traverse it, and the bottom is drilled with tiny holes. the air is sucked in through the pipe. pick the water in the bottom container, goes trough tje tiny holes and create a bubbling effect in the top container. Sorry for my poor english, that is my best try.
desperate coffee lover attached the following image:
ws-filter assy[996].jpg
 
desperate coffee lover
a view of the bottom of the top container
desperate coffee lover attached the following image:
ws-holes1[1004].jpg

Edited by David on 07/09/2008 8:58 AM
 
desperate coffee lover
the filter parts.two containers. a vac cleaner pipe that has been cut in length and drilled at the bottom. some mist filter cut from a humidifier filter.
desperate coffee lover attached the following image:
ws-filter parts2[1005].jpg

Edited by David on 07/09/2008 9:00 AM
 
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