I am building a 16’x23′ shop with benchsaw, radial arm, chop, and band saws, 8″ joiner, drill press, router table, planer and lathe. The dust collector will sit about ten feet from the room and I expect to design a system of ducts starting with either a 6″ or 7″ main feed with 4″ drops to the machines. I calculate that a minimum of 1200 CFM will be needed. From research, it seems I should be looking at cyclone systems since I will rely on it to clean my entire shop.
I have seen systems from Jet, Delta and PSI. What are the strong points of each, and what should be considered?
Jack
Replies
Having a cyclone to drop out the heavy material first is a great idea. The final filtration should be quite fine, because it is the finest dust that is the health hazard. I don't remember the micron size off hand.
Proper duct sizing is critical. If the duct is too small you won't pull enough volume of air to carry away the weight of material as fast as you generate it. If the duct is too large, the air won't maintain enough velocity to keep the material suspended.
I have a system from Oneida Air Systems, which I'm very happy with.
The muffler helped a lot and was worth the extra $40.
There are lost of prior posts in the archives.
IMHO, reducing the diameter of drops from the main doesn't make sense, if you're only running one machine at a time. This type of thing is done in big pro shops, where the main is handling the aggregated flow from several machines. In a 1-man shop, the main is handling the flow from just one drop. So the drops and the main should be the same size. Ideally, you'd keep everything 6" until you get right near the machine, and then step down to a short length of smaller diameter stuff to hook up to the machine.
I'm not sure how you derived the CFM you will need and at what static pressure reading that CFM needs to be obtained. Your plan on using 4" drops is a bit odd also. 4" has a lot me resistance than 6". If you're starting with a 7" main then you're probably looking at a pretty big system. Restricting that to 4" drops shouldn't be necessary or desired. Additionally, unless you are pulling big CFM through that 4" pipe, your 6" and 7" horizontal pipe velocities will likely be a bit on the slow side (sub 3000 fpm) to keep the dust from settling in the horizontal runs. Take a look at Bill Pentz's site for additional information on dust collecting.
I'm also unfamiliar with any cyclones that Jet or Delta provide. Manufacturers of small shop (as opposed to industrial shops only) cyclone systems that I'm aware of are Oneida, Woodsucker, Grizzly and PSI. Grizzly's new line of cyclones look very promising performance wise. Oneida and Woodsucker make proven high quality systems.
--Rob
Oneida will design a system for you. Give them the dimensions of your shop, tools to be used, etc and their experts will take care of the rest. Unless you are a professional HVAC person, you shouldn't be guessing about what it will take to have an efficient DC system.
-Bob
Oneida does do a pretty good job with duct design. The design they did for me was ok but did require tweaking. A good initial shot. Much of the problem evolves around the small dust hood ports of the machines and the design was made to fit the existing "poorly sized" machine ports. So if you use Oneida or similar design vendor, request that they (not you) specify the optimal tool hood size.
You need not be an HVAC expert to design your own effective DC system. You just need a little bit of knowledge (readily available at sites like Bill's) and the patience and time to review the information. If you don't have the patience or time, having a company such as Oneida or AirHandling design the system for you is certainly a good option but certainly not the only one. Of course having that knowledge will let you know if you are in fact getting good DC design advice.
--Rob
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