8" floor sweep and blast gate

[Chris Fairbanks]

Anyone know of a premade floor sweep and blast gate for 8" pvc duct? Finally getting around to finishing my clearvue install up and wanted to add a floor sweep and gate for it. Since I was going an 8" main I was thinking of going 8" for the floor sweep as well. Is that over kill? If no one knows of one I'll just make something. Thanks.

[Chris True]

Grizzly carries up to 7". http://www.grizzly.com/search?q=(nordfab)+AND+(category:%22Floor+Sweeps%2 2)

Nordfab lists 8" and even larger. The 'box' that sits on the floor is the same size no matter what the diameter though which is kind of interesting.

Yes, I think 8" is excessive :)

[Ole Anderson]

Because most floor sweeps require a vertical duct, I would opt for a smaller duct to maintain a higher velocity necessary to carry small off-cuts up the pipe. 5" or 6" would be my choice if you have a 5 hp system. Not likely you have less with 8" main ducts.

[Jim Becker]

Two of my floor sweeps are 5" drops and the third is a 4" drop. Only one uses a pre-fabricated floor sweep hood. The other two I made myself from a register boot. Even though that's slightly thinner metal, it's never under pressure since it lives beyond the blast gate. You should be able to fashion something similar even though your drop is plastic, although I agree with the others that an 8" drop is likely overkill for this application.

[Charles Lent]

I agree with Ole and Jim. A high velocity is needed to overcome the vertical rise of a floor sweep. Use a smaller pipe for the sweep and it will increase the velocity to better carry the larger chips up to the height of the main run. You may need to experiment to see what size will work best in your system.

In one place that I worked, the main run was slightly too large for the dust collector and larger chips would settle out or end up floating in the machine drops, half way to the main run. Depending on what we were doing, we sometimes had to stop and go from one blast gat to another, opening one or two at a time, to get the velocity high enough to get these chips up and into the main run, then open the gates farthest from the dust collector to clean out the over sized main,. Too large is sometimes worse than too small, and it all depends on the design sizes of the system. Be careful to maintain enough velocity in your design to move the larger ships. Planer chips will cause the most problem. Locating the planer near the dust collector will help with this, but even fine saw dust will settle out of the air stream if the velocity isn't great enough.

Charley