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Posted on Hype or something really innovative in dust collection?

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576 posts in 1291 days


#1 posted 06-23-2014 01:05 AM

Be sure to check the specs on the grizzly 443, it says it will flow 1025 CFM at 2.6”sp, that means at higher than 2.6” sp of duct losses the flow will go down. To give you an example of duct losses a 10’ section of 4” flex hose will drop 15” sp with 1000 cfm of flow. The same hose will drop 4.8 at 500 cfm.

The general recommendation for flow at most machines these days, to collect the fine dust that causes health issues is 1000 CFM. The grizzly will only do this if connected all the way to the machine with 6” duct with no more than 2 – 90 elbow and only a few inches of flex. Also if you plan to collect the fine dust you will need to modify the ports at the machine to either multiple 4” or upgrade to 6” ports

Most new woodworking tools are still not designed to allow for enough air flow to capture the fine dust, so it is up to us to modify them for our own health. I have modified 4 of my machines still have a few to go but I am getting there.

As for a dust collector for your shop, I would look for a cyclone that has a larger impeller 14” or 15” and can work to over come 10” or more in static. In my shop my worst run has 35’ total of 6” pipe with 3- long radius 90 elbow and one wye with zero to no more that 2 feet of flex. The static pressure measured at my dust collector is 4”

There are other ways to keep the height down, like the Grizzly 443 did use a smaller drum, you could remote mount the blower using a 90 on top of the cyclone, it would cost some efficiency losses but that should be over come by the larger impeller.

As for true cyclones I have seen them all sizes, commercial shops and schools have to plan for all machines to be used at the same time. So the flow requirements are much higher than in a one man shop. They have to have 20 ft tall cyclones with 20 – 100 hp motors.

Cyclones made for hobbyist work shops are designed to fit under a standard 8’ ceiling. To do this the cone to cylinder ratio as been reduced in most cases from the standard ratio of 3 to 1.64. Bill Pentz determined that this was a very effective trade off point between max efficiency and fit. Most of the designs on the market today have benefited from his research. But even at this modified design they still are true cyclones.

Another spec to watch for is the total filter surface area. A felt bag filter is between 20 – 40 sq ft of filter are the better grade systems will give you MERV 15 filters at 400 sq ft or more. That ten times the bag.

I have rambled on here. But do suggest that you draw up you system calculate your duct needs, then select a dust collector that will meet you needs. Bill Pentz has a great duct loss calculator at his web site here is a link to the calculator . http://www.billpentz.com/Woodworking/Cyclone/staticcalc.xls

-- John, Suffolk Virgina


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