Dust Collectors Set Up in Parallel
I just had an idea about how to enhance this air flow and I thought I would run it by the community. Please take a look at my sketch. My theory is that by combining air filtration for all of the individual units, the resistance per unit would go down and CFM go up. Each machine would have enhanced air filtration when running by itself and assistance when running in tandem with other dust collectors. The reason I went with the individual units was so that I did not have to calculate pressure drops, etc., and I did not want to run 10HP of collector to feed a 2HP saw. Does this seem too simple to work?
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Or, the gate could have a solenoid driven opening mechanism that is simply tied into a 24v AC relay. Turn on the blower and the gate opens... just like on the after market systems you can purchase to automatically open the gates on individual machines.
From contributor O:
Another thing to watch: If all collectors are dumping to a larger diameter pipe and only part of the collectors are running, you may not have enough sfm (velocity) to keep the "heavies" suspended.
From contributor R:
How loud are 8 dust collectors? How much time do you spend emptying bags? As far as hooking them up in tandem, I'd be concerned that the ducting might cause unbalanced loads on the machines and premature burnout. Each machine would have to have very similar ducting lengths, elbows, etc.
From the original questioner:
Thanks for your input. I had not considered the implications of back pressure onto the other pipes. The idea about introducing one way flow restrictors sounds like it would solve that problem.
What got me started on the whole idea was a custom felt bag we installed on the planer. A couple of years ago we installed a widebelt sander and shifted the 5 hp dust collector we had on the planer to the new widebelt. By default, the planer got a 2HP dust collector that was already in the building. The 2 HP collector was almost powerful enough, but not quite.
At the Seattle woodworking show we saw some custom size felt filtration bags by American Fabric & Felt Co. in Florida. It was only $100 or so to try the idea so we did. In the process, we also switched to a vinyl collector bag on the bottom. This new combination of collector and filtration bag made the 2HP collector seem like a 4HP collector. We were sold.
From there we made a purchase of (8) 2 HP collectors from Jet. These had been mispackaged with 5 micron bags, so we got a good deal on them. We set it up so that each machine would have its own collector and on some of the machines we installed new, bigger felt bags. We set it up with one machine/one collector for the reason of imbalanced air pressure that contributor R spoke of. What got me excited about the concept of integrating air filtration was the experience we had of more filtration = less resistance = better extraction. While up to four machines might be hooked up to one common collector, we were not trying to build an 8HP collector. Most of the time just one of the collectors would be running. I was just hoping that the extra bags would help us make longer runs. We have just completed a 30 foot run of six inch pipe to a 20 inch jointer.
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