What are the magnets for if you have a cyclone?
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What are the magnets for if you have a cyclone?
While I agree that the testers may have made a mistake, or may have had some serious bias going on, I have to disagree strongly with the idea that all cyclones are pretty much the same.
While every company seems to be learning from each other as time goes on, I still see significant differences in design:
Depth of the main cyclone body, and the ratio of width to depth.
How far the bottom of the body is from the collection bin.
Ratio of impeller diameter to blower housing.
Impeller DEPTH, for a give diameter.
Number of blades, and whether they curve or not.
The angle of the inlet.
Neutral vane, (most designs) vs a full helical air guide (ClearVue)
Quality of the motor
Shape & diameter of the filter plenum
etc etc etc...
And all that, before you even talk about the filters.
And then if you look at industrial cyclones, where height & overall size is not a concern, you can sometimes see even more design features, not found on "hobbyist" units, such as a large "turbulence settling" chamber installed before the bin, or an extra length of tubing in-between the blower and the top of the cyclone body, which probably aids separation a little bit.
I think Allan has hit all the high points of what features influence performance.
I'm also betting this has been covered, but just for anyone still reading - - my industrial experience (and THE DUST WEBSITE reading:)) has been that while Allan's features certainly influence cyclone performance, their influence is on 2 process conditions that ultimately determine that performance: 1. Entry Velocity - the faster the little dustimicules are moving, the more likely they are to remain sliding along on the cyclone body. The math is 1/2*m*V^2, so the V part gets important fast (no pun... ok, maybe a little pun) ; and, 2. Entry Turbulence - dustimicules' velocity becomes irrelevant if it is turbulent, rather than laminar (they need to move in a straight line).
No 2 systems will ever be the same (or even ideal), but if you can size the entry pipe to yield the maximum velocity right at the cyclone entry, rather than at a 4" gate (essentially an orifice into a 6/7/8"(?) pipe system) - performance should improve. I know this probably sounds counter-intuitive to most, but ....still. Design/build would be a bear, and a moving-target-bear at that.
I would be interested in what happens to any particular cyclone when the entry pipe is the proper length and angle vs. just slapping an elbow on the entry and zip tying a flex dust to the ceiling? I believe the rule of thumb is 10x pipe diameters of length in the entry run to get close to laminar flow. Flow straighteners might help shorten this length - or at least they do in metering applications. Tho' 25' tape measures would be a wrecking ball when they hit the straighteners.
I will just say that I think the writers for Wood report the results they got. I don't think they try to slant things. I did not like a recent review of track saws because I felt they somewhat unfairly maligned the DeWalt, which I have and like. I sent an email and got a courteous reply but not an apology or anything. Their main complaint was bowed tracks that had to be clamped. I have all the sizes of track DeWalt offers (3) and none of mine are bowed. But theirs were. If the parts used in their test were a fluke, then their results were not good information for them to spread. But how would they know?
Similarly, there may easily have been something wrong with the Clearvue they tested. Either due to their assembly or due to the manufaturing. But I don't know how they can do anything different than report what they found.
My personal opinion is that Bill Pentz trashes Oneida to the point of being less than truthful. I only have the little dust deputy but it works fine and I will soon add a super dust deputy to a HF blower. Bill wants to say that Clear Vue is clearly superior. I don't have personal experience with these big nice DCs but I strongly suspect that at least most of the units both companies put out work pretty well. I don't know which is better and doubt I will ever know because I don't want to spend that much for a DC. If I did decide to get a 3-5 hp unit, it would probably be the clearvue because last I looked it is cheaper. But if Oneida had a good price on their unit, I would not hessitate to go that way. Too many people are happy with both companies products for them to be generally an issue.