WIP :Water filtration dust collector, AKA: The Dust Bong

duffy99

duffy99

Joined
Apr 2, 2011
Messages
425
So I've been playing with this idea in my head for awhile and made a what I'll call proof of concept. It sucks air passively and stronger once I turn on the shop vac. It bubbles when in "passive filtration mode" and swirls . I'm pretty sure that I'm getting "clean dust free air" when I turn on the shop vac . I've been tweaking water levels attachments to the tubes and what not . Now I've decided to down scale it to a 5 gallon pail which should up the rate of suction and be able to have more water for filtration. Here is a diagram of what I will be building in the next few days and for humor purposes 2 pics of the original. I guess there is commercial products for drywall dust out there but this was all my idea.




Now the funny part , I'm well aware that the 120 cfm bathroom fan will get destroyed but I'm using what I have on hand right now , the small shop vac was on sale for $20 . I like duct tape as you can see.





Hopefully the next one will be much better. I think the concept is good though.
 
The smaller the bubbles that you pull through the water, the better. A large bubble will still be full of dust. Some sort ot aeration will help.
 
I could attach a large aquarium bubble stick to the tube in the water which should make the bubbles smaller but it probably would not work at all since I for see it getting clogged very quickly , the angled attachment is meant to make it swirl and not have large bubbles. Possibly adding a screen to the tube in the water? I'll try and see what happens. Also the hepa filter on the air outtake should stop anything that makes it through , thanks for the suggestions . This is a work in progress so hopefully with help I can make this a good functional dust collector/filter.
 
The HEPA should be adequate without the water, I think.
 
Hi Duffy.
Pleased to see you brought it to the forum. If you want a good bought one for dry wall dust look at some large dollars. Frank
 
Duffy,
Here are the engineering issues I see.

The setup you have made is basically a large atomizer. It will remove all the water from the tank as it becomes water mist. How fast it empties I can't say, but at the air volumes you are passing through the water, it is going to get sucked out. Each bubble passing through the tank will take a little water with it. Bubbles+air volume+dirt = foam. Someone suggested adding dish soap.....that would be unwise ,unless you want to have a room full of foam. I did research in my chemist days on defoamers to keep the foam down in pulp tanks, and I can absolutely say that you don't want any dish soap in the water of any bubble tank. Adding a defoamer like they use in carpet cleaners, would be a better choice........ if that was the only issue.

Now, where is all that moist air going.....through the shop vac.....and into your shop. You will be running a high volume humidifier in the shop. I foresee high humidity, rust, and mildew problems if this is used very often. I realize that in Alberta, humidity isn't a normal problem, but we southern cousins can attest that it can cause havoc with your tools and steel.

While passing through the shop vac, the wet air will saturate the filter, making the shop vac labor much harder to draw any air, and thus reducing the air flow as well as the vac life.

I also foresee the metal screen filter getting clogged up. It doesn't look like it is placed where it can be easily cleared .


The solution is a minor change to the inlet pipe on the tank. Make the inlet come about 6" from the tank bottom. Place only about 3" of water in the tank. This way the metal dust ,sparks, and heavy particles get trapped in the water, but the main air volume goes up toward the outlet and through the shop vac's fine particle filter. The air will be perfectly clean on exit from the shop vac. The box fan becomes unnecessary this way, too. You really don't want anything in the air path before the water trap . Adding a teaspoon of dish soap will be a good thing in this setup, as it will lower the surface tension of the water and make it catch the particles better. Dump the tank daily at the end of each days grinding.
I would delete the screen filter,too.
 
I like Chuck's design, very similar to what I have. I added some baffles to strengthen the main tube and a cheap 12v fan to move more air. The baffles help create dead spots of air movement where the dust falls out.

dust.jpg
 
This is excellent info , thanks Stacy . I really want to keep the fan as I want a passive dust collector to run 24/7 . What about angling the out take pipes end so that it's up reducing the amount of mist being picked up . Also having 2 intake tubes one in the water and one half in cut at an angle so that the sparks and dust are shot down to the water. Basically one for with the shop vac and another to be a constant dust collector? I could have a y with the ducting and close off one when running the shop vac.


bladsmth said:
Duffy,
Here are the engineering issues I see.

The setup you have made is basically a large atomizer. It will remove all the water from the tank as it becomes water mist. How fast it empties I can't say, but at the air volumes you are passing through the water, it is going to get sucked out. Each bubble passing through the tank will take a little water with it. Bubbles+air volume+dirt = foam. Someone suggested adding dish soap.....that would be unwise ,unless you want to have a room full of foam. I did research in my chemist days on defoamers to keep the foam down in pulp tanks, and I can absolutely say that you don't want any dish soap in the water of any bubble tank. Adding a defoamer like they use in carpet cleaners, would be a better choice........ if that was the only issue.

Now, where is all that moist air going.....through the shop vac.....and into your shop. You will be running a high volume humidifier in the shop. I foresee high humidity, rust, and mildew problems if this is used very often. I realize that in Alberta, humidity isn't a normal problem, but we southern cousins can attest that it can cause havoc with your tools and steel.

While passing through the shop vac, the wet air will saturate the filter, making the shop vac labor much harder to draw any air, and thus reducing the air flow as well as the vac life.

I also foresee the metal screen filter getting clogged up. It doesn't look like it is placed where it can be easily cleared .


The solution is a minor change to the inlet pipe on the tank. Make the inlet come about 6" from the tank bottom. Place only about 3" of water in the tank. This way the metal dust ,sparks, and heavy particles get trapped in the water, but the main air volume goes up toward the outlet and through the shop vac's fine particle filter. The air will be perfectly clean on exit from the shop vac. The box fan becomes unnecessary this way, too. You really don't want anything in the air path before the water trap . Adding a teaspoon of dish soap will be a good thing in this setup, as it will lower the surface tension of the water and make it catch the particles better. Dump the tank daily at the end of each days grinding.
I would delete the screen filter,too.
Click to expand...
 
Oh, I forgot to mention, you need to replace the flexible plastic hose with the flexible metal ducting for dryer vents. The plastic will melt.
 
zaph1 said:
Oh, I forgot to mention, you need to replace the flexible plastic hose with the flexible metal ducting for dryer vents. The plastic will melt.
Click to expand...

What about white PVC Pipe, would that work instead of the dryer vent?
 
Yes the hose will melt it was $5 and I just wanted to test the theory which seems to have been done before lot's in a different configuration . PVC will work but my thoughts were to have it flexible to be moved around the "shop" overhead to whatever I'm doing . I'll replace it with something that won't melt , I'm going to try the 2 intakes to see how it works. I understand the other designs but my whole idea is based upon the water acting as a fine particle filter. Once I fail I'll build the simpler design but there is no harm in following through with a project . If people just stuck to the known we'd never advance , I appreciate all the advice given and the designs and the science and logic behind them . I'll let you know the outcome if it's a success , if not just assume I built the simpler one.
 
I've never smoked dope (or anything for that matter) in my life, but I sure got a chuckle out of your thread title.

I noticed in another set of pics you put up your affinity for duct tape ;) :D I'd suggest Gorilla tape... it really is all that and a bag-O-chips! :)

Hope this works out for you. FWIW- Anything dust collection related can be thought of in terms of driving a car. 90 degree off ramps from the freeway and wash-board roads don't allow you to drive fast. Smooth, gentle curves, wide lanes, and SMOOTH roads allow you to drive fast (just like you want the crap from the grinder to get the hell through and out of the duct-work). So whenever you can use a connecting duct line with a small angle in relation to the main duct, as well as smooth walled ducting, you're WAAAAAAY better off. :)
 
NickWheeler said:
I've never smoked dope (or anything for that matter) in my life, but I sure got a chuckle out of your thread title.

I noticed in another set of pics you put up your affinity for duct tape ;) :D I'd suggest Gorilla tape... it really is all that and a bag-O-chips! :)

Hope this works out for you. FWIW- Anything dust collection related can be thought of in terms of driving a car. 90 degree off ramps from the freeway and wash-board roads don't allow you to drive fast. Smooth, gentle curves, wide lanes, and SMOOTH roads allow you to drive fast (just like you want the crap from the grinder to get the hell through and out of the duct-work). So whenever you can use a connecting duct line with a small angle in relation to the main duct, as well as smooth walled ducting, you're WAAAAAAY better off. :)
Click to expand...


Thanks I was going to have a 90 bend for the air out take in the bucket , now it'll be 45. I have it rigged with it blowing into the water and onto the surface , well it will be in an hour.
 
You are aware that with some engineering, you can use a velocity change and gravity to drop out the particulate in the case of metal and wood, without the added horsepower requirements of making bubbles right?

Funny concept though.
 
ron_m80 said:
You are aware that with some engineering, you can use a velocity change and gravity to drop out the particulate in the case of metal and wood, without the added horsepower requirements of making bubbles right?

Funny concept though.
Click to expand...

Could an electro magnet help pull the dust towards the water.
 
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