dust collector issue

CWendling

CWendling

Joined
Sep 10, 2005
Messages
518
So for the last few years my dust collection has been the small HF 1hp collector run through a 10gal bucket as a spark arrestor. The motor finally died and I upgraded to the larger 2hp unit with the big bag. Seems it draws a lot more air, as well as sucking all the water out of the 10gal can. So, Im thinking of going up to a 30gal can, in the hopes it would prevent the water from being sucked 3' high (exhaust tube in the lid of the can). Anyone else had this issue?
 
Could you just put a Y in the line & add a suction tube behind the grinder? I keep a box fan next to mine (right by the drive wheel), with a 20X20 filter taped on, to catch the fine dust that always floats around. You could add another inlet to accomplish the same thing, then keep your 10 gallon can.
 
Your piping on the spark bong may be wrong.
1)The port from the grinder should have a tube that goes down and stops about 8" above the bucket bottom There should only be around 4" of water in the bucket. That puts the incoming tube around 4" above the water.
2)The port that goes to the vacuum unit should only extend an inch or so in the bucket (or none at all). That puts the outgoing air as far as possible from the water level.
3)There should be a divider that goes down the center of the bucket to the same depth as the intake tube (8" above the bottom). It doesn't need to be air tight, but should fit fairly snug to the sides and top. I find a piece of wood cut to fit the bucket and attached with screws the sides works fine. You can caulk it if you want. The top should come reasonably close to the divider. If you want, put a strip of foam weatherstrip across the top of the divider.
You want a bucket the height of a drywall bucket - 18" is good.
 
Stacy E. Apelt - Bladesmith said:
ere should be a divider that goes down the center of the bucket to the same depth as the intake tube (8" above the bottom). It doesn't need to be air tight, but should fit fairly snug to the sides and top. I find a piece of wood cut to fit the bucket and attached with screws the sides works fine.
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Stacy - sorry - im not quite clear on this. Does this divider extend only from the side to roughly the center of the bucket (i.e. only halfway across)? Perhaps so that the inlet and outlets are on opposite sides of the divider (forcing the air flow to kind of "circle" around the bucket before hitting the outlet opening???
 
how high above the waterline was the suction tube and how many inches wide is the tube ? i have never heard of the water being sucked out of a spark bong :)
 
The divider goes from side to side down from the top. This makes the airflow go down the intake tube carrying the sparks toward the water, then back up toward the vacuum port.
 
20191209_152738.jpg 20191209_152852.jpg Never had a divider in there. Heres how its set up. The duct inlet from the grinder goes down about 4" from bottom and i keep about 2" water in it. The exit from the bucket (to the motor) initially only was ducted into the lid and was about 1-2" inside. I added one curved 90 to put that part in the middle of the bucket, thinking it would stop sucking water up the sides or whatever it was doing. It continued, so I put another 90 so its now pointing up (in the pic may look connected but theres about an inch gap between the 180 piece and the lid. So, unless my logic is wrong, it has to be pulling water from the bottom, up the sides, and over.
 
For additional info:
The reason you use a down tube instead of just having the sparks/dust enter on one side of the barrier is it keeps the stream velocity high until it exits the tube. Then the pressure drop allows the sparks and heavy dust/grit stuff to drop into the water. Only very fine dust will go on to the vacuum.
 
You're agitating the water with the airflow, which is suspending little droplets of water and water vapor, which is then sucked into your dust collector. The baffle Stacy mentioned might help. Also, placing the outlet at an angle will help, making the air inside swirl like a cyclone, giving the water droplets more time to settle out of the airflow.
 
Sam Dean said:
You're agitating the water with the airflow, which is suspending little droplets of water and water vapor, which is then sucked into your dust collector. The baffle Stacy mentioned might help. Also, placing the outlet at an angle will help, making the air inside swirl like a cyclone, giving the water droplets more time to settle out of the airflow.
Click to expand...
It was at an angle when i added the 90 at first. that didnt work so added another
 
That is why I suggest the down tube end 4" above the water. The air stream will lose velocity quickly and not roil the water.
 
So, I added a baffle and cut the downtube. The bucket is about 16" tall. Tube is 8", so 8" from bottom as is the baffle. Doesnt matter if i have 4", 2", or 1" of water in the bucket, its still getting sucked out. On the plus side, I cant complain that the HF dust collector isnt pulling air ha. Im just trying to figure out how to make it work. Cant have all my water going into the dust bag.
 

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Im thinking so. I went from a 1hp 650cfm to a 2hp 1550 cfm. Before I have to rearrange my whole bench to accomodate a full size trash can for a spark trap instead of the smaller one i have. I cant imagine it would suck water up 30something inches if i use a 30gal trash can instead of the 16" tall one. I cant be the only one using the 2hp HF dust collector, so was looking for suggestions
 
Normally, all you need to decrease air speed is to increase port size. Since you have a good size port, I would suggest a larger can.

As an experiment with the current setup, cut the down tube about 1" past the lid. That should drop the fow speed drastically and prevent the water being roiled.
 
You could also consider putting a dust deputy between your bong and the vacuum? Just accept the water coming out of the bong, and let the dust deputy collect it?
 
i think for the rate of suction you seem to have, both tubes are too close to the water. i think you need them shorter like stacy suggested.
 
Stacy E. Apelt - Bladesmith said:
Normally, all you need to decrease air speed is to increase port size. Since you have a good size port, I would suggest a larger can.

As an experiment with the current setup, cut the down tube about 1" past the lid. That should drop the fow speed drastically and prevent the water being roiled.
Click to expand...

Looks like a larger can it will be. I cut both in and out tubes to about an inch under the lid. Still sucking water out of the bottom. I think its actually creating enough of a vacuum in the can that its pulling it up the walls of the can as well, and then to the tubes
 
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