[Ruud], the creator of [Capturing Dust], started his latest video with what most of us would consider a solved problem: the dust collection system for his shop already had a three-stage centrifugal dust separator with more than 99.7% efficiency. This wasn’t quite as efficient as it could be, though, so [Ruud]’s latest upgrade shrinks the size of the third stage while increasing efficiency to within a rounding error of 99.9%.
The old separation system had two stages to remove large and medium particles, and a third stage to remove fine particles. The last stage was made out of 100 mm acrylic tubing and 3D-printed parts, but [Ruud] planned to try replacing it with two parallel centrifugal separators made out of 70 mm tubing. Before he could do that, however, he redesigned the filter module to make it easier to weigh, allowing him to determine how much sawdust made it through the extractors. He also attached a U-tube manometer (a somewhat confusing name to hear on YouTube) to measure pressure loss across the extractor.
The new third stage used impellers to induce rotational airflow, then directed it against the circular walls around an air outlet. The first design used a low-profile collection bin, but this wasn’t keeping the dust out of the air stream well enough, so [Ruud] switched to using plastic jars. Initially, this didn’t perform as well as the old system, but a few airflow adjustments brought the efficiency up to 99.879%. In [Ruud]’s case, this meant that of 1.3 kilograms of fine sawdust, only 1.5 grams of dust made it through the separator to the filter, which is certainly impressive in our opinion. The design for this upgraded separator is available on GitHub.
[Ruud] based his design off of another 3D-printed dust separator, but adapted it to European fittings. Of course, the dust extractor is only one part of the problem; you’ll still need a dust routing system.
Thanks to [Keith Olson] for the tip!
I really enjoyed this, thank you.
How much more energy does it use now
That was not the efficiency metric specified ;)
Curiously, fans generally draw less power when the filters are clogged or otherwise present higher resistance. Accelerating less air to speed means less kinetic energy goes into the air. That (generally) reduces the power requirement at a faster rate than the increased pressure differential increases it, so it’s a net total power reduction.
Try it yourself next the time you use a vacuum cleaner: Block the intake — you’ll hear the motor speed up due to reduced load.
The energy to run a fan is proportional to the pressure difference across the fan and the volume of air going through the fan. Blocking it off brings the flow to zero, so even if you have a high static pressure the energy used is zero times that (plus mechanical/electrical losses).
That’s a very first order approximation.
I believe if you look it up, you will find boundary conditions apply.
Stalled airfoils take more energy to push at a given speed.
With no airflow, each blades angle of attack is it’s physical angle.
Which means it’s stalled, perhaps not at the blade tip.
Might just spin up the air though.
Devil is in the details.
For example, my vacuum bogs down when the filter needs cleaning.
Different impeller shapes and sizes.
I love that there are random folks on youtube who dedicate their entire life to some incredibly specific thing like dust collection.
I wonder if he ever has time to actually make anything in his shop?
He made a dust collection system.
Yeah c’mon man. Duh. And also he made some cut-offs to produce the testing dust. Get with it
Not to mention all the dust he produced!
I realize the incentives don’t work out; but it would be neat if more niche industries were self-documenting more often.
Something like dust collection is a nontrivial occupational health and safety matter(whether it just be comfort and required PPE or horrible degenerative lung diseases and periodic fuel air explosions); and just brute-forcing it rather than playing smart is probably megawatts of wasted power; so there’s presumably a specialty supply chain of people whose entire careers are dedicated to obsessively high standards in dust collection and the sort of hardware and expertise justified by that level of compliance and opex spending.
It’s just that there’s not a lot of incentive for those guys to sink a bunch of time into disclosing a lot of detailed potentially-business-sensitive information; so we mostly rely on lovably eccentric hobbyists.
The sawdust came from somewhere!
Even Germans have to make a fair amount of dust before they buy a dust collection system.
They’re not Swiss.
They do the math.
Which has a lower present value:
(Cost of extra time spent cleaning – Benefit of annoying neighborhood w dust) vs (Cost of dust collector – Value of pure dust).
(I hope the dude is German. Didn’t watch the clickbait.)