View Full Version : Had a Brainstorm today.

Kevin Gerstenecker
03-06-2003, 9:15 PM
I was thinking over the Downdraft Sanding table idea today, and I had a thought. With a new Dust Collection System on the way, I was thinking of maybe utilizing it for dust collection for a sanding table? With the addition of a 4" or 6" port, how would this work for providing enough downdraft to effectively control the dust created when sanding. I was thinking along the lines of a 4' x 4' perforated table/cabinet combination. When it comes time to sand, just hook 'er up to the dust collector, open the blast gate and do my thing. If the plenum of the sanding table is just 12" deep, or less, would it provide adequate dust collection? Also, I was thinking along the lines of 1/2" or 3/4" holes in the sanding table, to help equalize the suction distribution. What do you all think of this idea.......................yea, or nay? It was just a thought, and I thought I would get some feedback from the Veterans here. As always, any and all ideas and comments are appreciated.

By the way, my dust collection system will be a 2 h.p. system, 220V, 1550 cfm.

03-06-2003, 9:33 PM
Well I'm not quite a veteran, but I have heard of others doing the same thing and have had good success. I think the 1/2" holes would work better, because they would pull a harder suction than the 3/4". But with 1550cfm you shouldn't have a problem if this is the only blast gate open at the time.

Ken Frantz
03-06-2003, 11:48 PM

Go over to the Design Fourm and read the post and the replies that I started "AIR OFFEED TABLE".

Also I have a post I just started "JUST OFF OF THE TOP OF MY HEAD" there.

Lee Schierer
03-07-2003, 12:56 PM
I'm not an HVAC engineer, but I have some understanding of hiow it works. In your 48 X 48 table if the holes are 1/2" dia and on 1" centers, thenen there would be 2116 holes in the top. Each hole has an area of .785 square inches. Your opening sucking in air totals 1661 square inches or 11.5 square feet. if your DC moves 1550 cfm, then the velocity through the holes is 134 feet per minute, neglecting friction and numerous other losses. This would seem fast enough for dust pick up near the openings.

Whether you would get dust settling out ing the plenum is beyond my skill level to calculate. I suspect there will be some.

If you restrict the air flow from teh rated level for the DC, your velocities will drop accordingly. If the DC has a 6" inlet and you use 4" pvc, the pressure drop will be significant and the air flow will be reduced by a large amount. A 4" pipe has less than half the surface opening of a 6" pipe.

Hope this helps.