Thread: Dust collector-water filter

There is a commercial incinerator in Auckland (NZ) that uses just that principle for cleaning the smoke from the incinerator before exhausting it.

Yeah - serious loss of suction - depending on how deep the tube is, the vacuum cleaner / dust collector has to lift that equivalent weight in water continuously. The tube would have to be deep enough in the water to actually cause it to bubble, rather than just pushing the water out of the way to have a chance to collect all the dust. The system could be improved by adding a small amount of detergent to the water. Not enough to cause a cascade of bubbles through the workshop, but enough to decrease the surface tension of the water, making it easier for the dust to get wet, and therefore trapped. A small amount of frothing is a good thing - aids the collection process in the same way as foam on a beach.

Originally Posted by ronnchy

Is it really that simple? Somehow I don't think so. I imagine the collector would probably lose some serious suction.
Any ideas/comments would be great.

Correct, as Stu says serious suction loss. The system you describe works for High pressure low volume systems. DCs are the opposite, they work on High volume, low pressure. Even the higher powered units only generate 10's of inches of water pressure differential. Most of this is often used to move the air and dust through the ducting and the there is often little left to force the air through the filter bags. If you were then to add a water head to the end of a regular DC the suction would drop to a poofteenth of BA.

Best Solutions - cyclone, or put the DC outside the shed.

Cheers

You'd do better adding high pressure fine water mist(after bag filters)we do at work... but Our 2 extractor fans are about 5m in dia driven by motors about the size of a medium car!(the 206m high outlet stack can be seen from about 50km away!)
The whole air flow must go through the sprays.

Originally Posted by Harry72

You'd do better adding high pressure fine water mist(after bag filters)we do at work... but Our 2 extractor fans are about 5m in dia driven by motors about the size of a medium car!(the 206m high outlet stack can be seen from about 50km away!)
The whole air flow must go through the sprays.

Now I'll bet you must get some nice sludgy stuff out of that lot?

I think there may be a good chance that this would work but in a different form.

Some spray booths work on a water filtering system, the most common is one by Binks bullows.

It uses a trough of water and above it is a saw tooth opening touching the top of the water. Air is drawn through the teeth and it makes the water rise into the exhaust duct. Inside the duct are baffles and the water drawn up eventually falls back down and over the baffles.

This makes it necessary for overspray, dirt and fumes to pass through the water spray which collects them. It is rated at about 98% efficient to stop all pollutants reaching the outside air.

I've used one to collect sanded dust from paint and no dust gets past the water fall. Whether it would be worth the time and effort to match your dust extractor up with such a device is another thing.

OH, and when you need to clean out the water you are scooping up sludge from the bottom of the water tank. Messy!!!

I once worked in a weaving shed, and it had a fine mist going at all times, as the looms were running 24 hours a day. It collected the fine lint and deposited it onto the floor, (and workers), and everything else, but made the lint manageable. The mist could hardly ever be felt on ones face so it was very fine.

To apply that idea to fine sawdust, may mean the stuff is landing on everything in a damp condition, saw tables etc; starting rust as soon as it lands. Once damp, it may also breed some sort of nasty as well.

Look up wet scrubbers.

Pressurised water sprays to clean up exhaust air.

Now I'll bet you must get some nice sludgy stuff out of that lot?

Thats why they use it, the sludge is pumped back into the process, no wastage.