I learned with my solar thermal experiments that static pressure is as important as airflow when it comes to accomplishing work efficiently. Few channels do experimentation like this, not as many clicks as crushing things in a press or blowing it up I guess, but I appreciate the data. Very useful. Thanks!
Never claimed to be smart bud. Just pointing out that though most of the gen public would find this boring, I and likely most of Matthias's subs appreciate the extra effort to show exactly why one configuration is better than the other. Everyone owns a channel for different reasons: some informative, some entertainment, some for clicks and $, some just to goof around. I think (almost) everyone can be as smart as they choose - most people seem to be pretty clever when they want to be...
@@satibel Best cooling came from a Siemens i used to own. All the fans were oriented towards high static pressure. Temps never rose above 50C in any of the stages of use, regardless of how much number crunching i was giving it, but then again Siemens used to make some bitching portable server cases, with airflow in mind (haven't used on in many years, having gone to liquid cooling).
awe You forgot the statistics in the science department! You need a repetition of 4-5 (maybe 20) depending on the Power you want/reduction of non-systematic errors/outliers and to achieve some sort of normal distribution of the recordings. Then you may call this an experimental Science video, not just a Screwing Around demonstration video. ((but this calls for building a zillion blower houses -- I didn't count the configurations/designs/ie treatments he made so I'm guesstimating -- but then, Matthias isn't the pedantic type, unlike me))
perhaps add smooth hose versus flexible/concertina hose to your comparison chart... tho that then brings in a whole new discussion about surface/laminar flow :)
These hoses are actually quite smooth inside. Besides, wobbly surface could have better performance, especially for curved paths. Watch Mythbusters video about golf ball aerodynamics, they've explained it quite throughly.
To find the most efficient shape for a fan, just look at fans? The blades are in a spiral but they're also curved diagonally. Airflow fans use +-12 smaller blades with gaps between the blades so air can more freely flow through it. Air pressure fans use +-6 bigger blades and are spaced closer to each other so the air builds more pressure before it is released. The designs aiming for a mixture of both use +-6 bigger blades with extra gaps between.
From what I've observed, forwards facing curves are more efficient at producing high outlet pressure while backwards facing curves are more efficient at producing high inlet vacuum levels. So, for a dust collector, backwards facing is better.
Since you keep mentioning noise I'd love to see you do an experiment with asymmetrically-spaced blades and an explanation of the effect on noise. (Awaiting classic Matthias response "Nah, too much trouble, just wear ear protection") Favorite channel on youtube - thanks for the great videos!
Thank you for the great demo. However I wished you also showed the change in static pressure at the outlet. For all the applications when you need to pressurise a space. Can you please show that in a future video. Only you can do it 😊
"Restricted Mode has hidden comments for this video." not sure if you have noticed Matthias Wandel is now being censored by youtube if you have restricted mode on...
Is it an option to have multiple exits? My water pump has an enclosure around the blower in which the directions of the exits are in the direction of the flow. This 'forces' the airflow out (like with one exit), only now with many exits
how about trying to out a two piece spiral housing part (2 "half circle" shaped ones) and place them so that there is one outtake hole at the opposing sides? by the way... nice JUNK :P
Also, i wonder if you make the impeller taller/deeper but a smaller diameter, so it will have less leverage of load, but the similar surface area so it doesnt slow down as much under have load?
bgdwiepp it's usually the other way around, broader blades providing better static pressure but less airflow, and more slender blades providing the opposite
nope. you're got it backwards, think about all your high airflow fans (props, box fans, ceiling fans, etc), these all have basically the minimum number of blades because there is near 0 static pressure requirement. as the static pressure reqirement goes up the number of blades go down (car radiator thermofans, ducted axial HVAC fans etc). a super obvious example is axial PC case fans, google image search "high air pressure 120mm fan" and "high air flow 120mm fan"
Companies nowadays are desperate for research to make things more and more efficient and economical. It is less of quality an more of efficiency so the company can make more money
I would think that stator vanes like the once you would find in the compressor for a centrifugal flow jet engine would increase static pressure but I wonder if it's better than the housing. turbomachinery.asmedigitalcollection.asme.org/data/journals/jotuei/926080/061034_1_f1.jpeg
From what I've read so far: flexible tubing with its ridges introduces a lot of pressure drop especially in any bends. Ironically in HVAC systems all the bends ought to be done with rigid smooth walled piping if possible but you can use flexible tubing for the straight runs (and nothing else) if you want due to its ease of transport and installation!
Flex will always bring more disturbance than smooth wall. In ducting its key to run your main through the house and then use as little flex as possible to connect vents in odd areas. We do see a lot of flexi duct being used now but you as the consumer have a voice. It has to do with how much you are willing to pay and proper planning for a project. Shortcuts always cost you more money in the long run!
I realize I am late to commenting on this video but was wondering if the shape of the cyclone matters? A lot of the commercially available cyclones are cone shaped with the exhaust at the top, where as yours is just a cylinder? Would the cone shape help push the air up towards the top and therefor decrease restrictions?
You should try to get your hands on a blower for a small bounce house. I have one left over for my sons bounce house from when he was a little boy... thinking about making a dust collector for my sanders with it.
I have couple of ideas. Test some variables: Distance from lid to impeller. Size of inlet of impeller. Impeller with and without top ring. Fix description: eirflow->airflow Moe->More
Thanks very much for this Matthias. I have worked on industrial dust collection/ air movement systems my whole career and i have seldom seen these sometimes counter intuitive engineering principles explained so clearly. Well done, you have a way with words (and video). Forget the pedantic types, I suspect most of your viewers, like myself, don't have any time for them either... aren't they first cousins to trolls on the evolutionary tree?
FANtastic. Oops, did I just write that? Your work with these systems is amazing, and I am sure we are all learning something new with each experiment you perform. I am so gonna try making one of these in the very near future. Keep up the good work.
Yesterday while raking leaves, I had a brilliant idea! Why not make one of those into an electric leaf blower? Once I find a motor, I am going to do that! Less raking, and less awful 2 stroke exhaust!
You should look at air handler blowers. They use squirrel cages with the curves in the direction of rotation. Opposite of a water pump. It comes down to if you want high CFM or high Static
So now are you going to go back and optimize the wheel size for the dish washer motor and for static pressure? And correlate that back to the flat paddle test for motor output? As in what wheel dimensions and vane count is equivalent to a paddles length. I noticed the wheel you built here, under loads the motor some. Also what is the correlation in wheel thickness - diameter - center hole, dimensions. Me having a couple of those motors sitting around has nothing to do with these questions. :)
Hello Matthias, First of all, I want to thank you for your extensive and educational videos! They are truly amazing! Very useful, especially now that I'm planning to make my own fan. Secondly, I have a question: Have you ever considered making a double suction blower? And if not, why not? Greetings from Holland!
This was a really informative video Matthias. Thanks for making it and other ones like these! It doesn't seem to matter what topic you chose (wood, shop, home, camp, random) I always enjoy your style and learn something. Please keep making them!
you could try fewer or less fins on the fan changing the shape of the fins adding a dome or cone in the center trying sharp or dull edges, since most fans have a thick body but sharp fin edges. polished or rough / soft surface on the fins (a pc fan manufacturer used some sort of fleece on the fins to reduce noise.)
Dismanteling and old shop vac i realised the suction area inside the shop vac is like an rolled up smooth pipe. So i was wondering if cutting the outside of the propeller not square but roundish and having the housing area curved as well (creating the hollow pipe idea) would that be an improvement?
With a centrifugal compressor it probably is indeed most efficient to collect the air equally from every side of the impeller. This arrangement would be kind of like in early British and American jet engines which used centrifugal compressors - the air was pushed into ducts laid out around the compressor, and into the combustion chambers, and then through the axial turbine that powers the compressor. But, it would make for a rather complicated design with a lot of ducting, and the ducting itself could actually end up hinder the airflow more. Most centrifugal compressors used in turbochargers have the spiral or snail shell-like housing, so probably the simplicity from having one outlet outweighs the advantages of multiple outlets set equally around the impeller.
I had a similar issue trying to lengthen a AC venting hose in my bedroom. It came with like a 10ft hose, and I tried to add another 8 feet or so, and it just couldnt evac the hot exhaust worth jack all. Go back to the factory length and it was cold, add my extra 8ft, the room barely got cool.
okay here's my scenario it doesn't really involve joyner's planers or table saws or any of the wood dust collection that you're dealing with my situation is dealing specifically with dust collection from a four and a half inch Grindr using 36 Grit sandpaper and it produces an enormous amount of dust so much it covers everything in the shop and I guess I was just trying to find something that had an enormous amount of suction that could deal with the situation.
Stupid idea may well be stupid ... but here goes ... What would happen if you reduce the impeller height by half, and have the fins on the bottom going backward, followed by roundel of plywood, then a second set going forward, topped off by another roundel of plywood, with both spinning on the same axis, either on a common shaft, or a shaft-within-a-shaft arrangement (which would be a nightmare to engineer) ... The reason for asking was Dyson at one point at released the DC-O1, a washing machine that had a split drum that contra-rotated, which supposedly was more efficient in washing clothes ... (although was withdrawn from market due to problems ...) ... I presume that the airflow upwards would be very chaotic, possibly increasing the power load, whilst negativly affecting airflow velocity, and dynamic pressure, but it would be fun to see whether I'm right, or wrong ...
I was planning to make an heat exchanger, and doing some guestimate, I figured that the pressure was an huge factor, and caused an huge flow loss. I'm still looking for some inexpensive blowers for it, and I can't find anything with enought CFM and pressure. I might be forced to actually stack two, one on the intake and one on the outtake, just to get enought pressure... A royal PITA for sure.
Have you had a look at using small splitter vanes between the leading edges of the blades? It looks like a very easy thing to add in and apparently helps with static pressure of backward bladed fans. (see "Impeller Treatment for a Centrifugal Fan using Splitter Vanes - A CFD approach" for more info)
I just watched your chicken wire filter from 2016 and wanted to let you know about the centrifuge design. Sure enough a quick search and it looks like you're already on top of it! Why do I know about this design? I wanna see if it's effective for cleaning impurities out of the air during a dust storm - Say in the desert or on mars. :D
I have no dust collector because I ussually do woodworking outdoor. I have no skills on building this machines. I do not have those measurement instruments... but, I'm engineer, I do woodworking... and enjoy like a kid with this kind of videos. Thanks!
Now remove veins from the impeller and I bet you increase airflow and noise. I'm not sure what you do with pressure, and if you put the veins at a greater angle you'll increase pressure.
Restricting the size of the hose would also improve air pressure, maybe you could experiment with that, I thought also something similar to a beater bar to break up the path of sawdust/chips like an upright vacuum uses would help with air flow without increasing motor size and/or suction either, also would agitating the air flow by interrupting suction possibly by using an elliptical blower or one way valve make a difference? but as a last resort wouldn't just increasing the brute force of the hp/amps of the motor help with atmospheric pressure?
I'm sure this is an obvious point, but they teach blower design in mech engineering disciplines and there are comprehensive blower design text books on this subject already. What there _isn't_ is a decent software application that takes those calculations and puts them into a reasonably priced design package...similar to woodgears.ca/gear_cutting/template.html . ;-)
Hi Matthias, i've built a dust collector myself With a cyclone dust separator but i have a problem, The impeler keeps clogghing with wood chips mostly when i am using the thiknes planer, i think the problem it îs în the cyclone, i put in the center of The cyclone a pvc pipe of 110 mm în a way that îs a bit lower than the intake of The cyclone, What do you think it needs to be shorter?
I'd always heard that something like a shop vac would make a lousy dust collector as what you'd really need is the high CFM of a dust collector fan, but this data seems to indicate otherwise. Is that advice I've heard true or am I misunderstanding something? Thanks.
Your conclusion in the middle part of the video, depends on whether you are sucking or blowing. It also depends on whether you actually want to do anything with the air you are shifting. Since your blower is at the end of your process, you don't care whether the air goes after you have propelled it.
Wonder if a larger diameter cyclone can would greatly benefit the system? I'm now going to look at changing my hose system to use a few short pieces of flex interspersed with solid sections of pipe. My shop layout can support this, YMMV.
the difference in the sharp edge in the spiral housing comes with pressure build up at the blowing side, as does most of the benefit of the housing itself. that being said, since you have made a rather robust blower, wouldn't it be better to blow trough the cyclone instead of sucking trough it? this would mean getting dust in the blower but it looks like it can handle that, plus the dust wouldn't pile up in the high flow areas. building pressure is easier than removing it, since the air needs something to push against to impart energy, building 0,3bar abs requires about as much energy as building removing another 0,1bar from that, given a closed volume. then again it might make 0 difference given the large restriction of the hose and this device working more on mass flow than pressure (though as you pointed out, pressure is still important)
Talking about centrifugal force is just like talking about the Coriolis force or the force of God; it's just a matter of convenience even though we all know that they don't really exist in any real sense. Not a problem.
How about the dimensions of the impeller? If you resize it to have a bigger diameter and smaller height. (if you think it as a cylinder), what effect would that have on the pressure? In other words, Is it better to make an impeller with a large diameter or a tall one to have lots of static pressure? I'm guessing sacrificing height for diameter results in less airflow but more pressure.
I'm sure it's been said but I would love to see a comparison of differing lengths of solid pipe and flex pipe with the same length run. I'll be honest most of this video was over my head but I'm sure once I'm working on a comparable project I can refer back to this and get more necessary information.
I'm curious if a completely smooth hose would make any difference compared to the ribbed hose you have. Also would a straight tube/hose be any different than one that has a lot of 90 degree turns?
if you wanted a LOT of static pressure it seems you would need a really big blower. but noise and power consumption would obviously increase, and its less efficient for the same motor size. Im wondering if there is a series or parallel configuration where you could run two smaller blowers, and generate the same static pressure of a single large blower. But both motors draw less watts combined than a single motor.
just a question, what if you somehow included the Tesla Valve and/or turbine in to the equation, would or could you produce a more efficient outcome??????
have you tried making a stater? also, this should work differently when on the exhaust port vs on the intake for a pressure reading. considering your readings i would make a wheel that more closely matches your system, thinner and larger diameter. should give the benefit of having more differential pressure and less noise. but you wont have the mass flow when you disconnect the hose ect.
Now the only thing left to make a perfect dust collection system is comparing the effiicencies of various cyclone shapes, cylindrical, conical and sizes (and inlet and outlet pipe shapes and sizes and depths)...
I made some experiments with cyclones and airflows myself and came to an interesting conclusion: The diameter of the cyclone is surprisingly irrelevant. I thought a smaller cyclone would make for faster rotation and thus for more resistance but I tested three variants from 400mm to 590mm diameter and they were pretty much equal. Also there wasn't much difference in their ability to catch the dust. So I went ahead and ordered one of the totally overpriced dust deputies (125mm inlet version) and was really surprised: With that cyclone the air flow almost doubled. I don't know why the air in there rotates so much more "efficient" but it has a lot less resistance and I don't see a difference in it's performance yet. Still most of the dust goes into the bin. So it seems to be a good product, but the price... nah. But if someone here reads this and is thinking whether the effort of building one on your own is worth it: Yes, it is. Marius Hornberger has some videos about it. Hope this helps. Took me several days to build all those cyclones. For separation it doesn't matter what design you chose, but for airflow: Use the cone shape. Wish I could explain why.
Rainer Zufall, Marius, and Matthias have explained this in older videos to some degree. Also Phill Thien's website explains why the baffle has less air flow, but keeps the dust rising out of the collection bin when it gets almost full. Basically, the baffle creates a positive pressure lobe at the center, causing a lot of resistance. Well, that's the best way I can explain it.
I only know all the videos from the first two :) At least I cannot recall any comparison but they have a lot of videos and I have a bad memory so I may be missing something. But today I want to add: Just in case someone wonders how good the dust deputy is at separating fine dust from 120 grit sanding: It is pretty much 60-70%, which I think is really good. Did a lot of sanding today with my drumsander. 30% goes to the filter but considering we are talking about really fine stuff I think that is good performance. I wonder if you can get more performance with another setup. With the good airflow a two stage cyclone would be possible but will it really help... hmmmm.
Anyone know how to choose the best angle and curvature for the backward curving blades? Is a circular arc shaped blade optimal or should the curve become less tight going from the center of the impeller to the outside?
great video ,,,, explains a lot , the length of flex hose will probably effect it as well ,,,, seeing that the hose had the biggest resistance ,,,,, would be nice to see the resistance from 90 deg elbows and 2- 45 deg and flex pipe like for a full shop dust collection set up
The manufacturer of those tools are probably hate you right now because you said you were putting "junk" in the cyclone. Pretty funny joke if it was intentional.
That increased noise when you closed that gap was just the wooden plank vibrating like a diving board. I don't think that noise would be there if that profile was rigid.
Could you please please try adding some veins to it! It's suppose to increase the pressure by converting the kinetic energy to potential energy but I've never managed to wrap my head around it.
The spiral housing is restricting the output of the fan. So of course it sucks more without the spiral housing. However, if you want a blower, then you need to conduct the same experiment and test the output wind speed rather than the inlet air speed.
I learned with my solar thermal experiments that static pressure is as important as airflow when it comes to accomplishing work efficiently. Few channels do experimentation like this, not as many clicks as crushing things in a press or blowing it up I guess, but I appreciate the data. Very useful. Thanks!
Static (back) pressure is one of the most valuable data points even for PC coolers but is the most overlooked as well.
Most channels can't analyze data, and don't want anything but money.
Never claimed to be smart bud. Just pointing out that though most of the gen public would find this boring, I and likely most of Matthias's subs appreciate the extra effort to show exactly why one configuration is better than the other. Everyone owns a channel for different reasons: some informative, some entertainment, some for clicks and $, some just to goof around. I think (almost) everyone can be as smart as they choose - most people seem to be pretty clever when they want to be...
high cfm fans are good for cases, high static pressure fans are good for heatsinks.
@@satibel Best cooling came from a Siemens i used to own. All the fans were oriented towards high static pressure. Temps never rose above 50C in any of the stages of use, regardless of how much number crunching i was giving it, but then again Siemens used to make some bitching portable server cases, with airflow in mind (haven't used on in many years, having gone to liquid cooling).
You inspired me in my "this is NOT a propeller video" and this one is great as well
Remember kids, the only difference between Science and Screwing Around... is writing it all down!
I love this comment! :D
awe
You forgot the statistics in the science department! You need a repetition of 4-5 (maybe 20) depending on the Power you want/reduction of non-systematic errors/outliers and to achieve some sort of normal distribution of the recordings. Then you may call this an experimental Science video, not just a Screwing Around demonstration video.
((but this calls for building a zillion blower houses -- I didn't count the configurations/designs/ie treatments he made so I'm guesstimating -- but then, Matthias isn't the pedantic type, unlike me))
so true
i was about to say that XD
...quoting Adam Savage without giving credit, I see...
Awesome explanation. I love these blower/dust collection videos, it gives so much insight for when I build my own from scratch ...some day.
perhaps add smooth hose versus flexible/concertina hose to your comparison chart... tho that then brings in a whole new discussion about surface/laminar flow :)
These hoses are actually quite smooth inside. Besides, wobbly surface could have better performance, especially for curved paths. Watch Mythbusters video about golf ball aerodynamics, they've explained it quite throughly.
Even if that's the case, that may change when you add dust and other debris to the airflow.
thinking that too
Woo, that would be neat. IIRC you can get laminar flow by just putting in a whole bunch of straws in a lattice.
To find the most efficient shape for a fan, just look at fans? The blades are in a spiral but they're also curved diagonally.
Airflow fans use +-12 smaller blades with gaps between the blades so air can more freely flow through it. Air pressure fans use +-6 bigger blades and are spaced closer to each other so the air builds more pressure before it is released. The designs aiming for a mixture of both use +-6 bigger blades with extra gaps between.
I think that these experiments you do are way more interesting than your standard (but still immensely interesting) videos.
From what I've observed, forwards facing curves are more efficient at producing high outlet pressure while backwards facing curves are more efficient at producing high inlet vacuum levels. So, for a dust collector, backwards facing is better.
Brilliantly illustrated!
Since you keep mentioning noise I'd love to see you do an experiment with asymmetrically-spaced blades and an explanation of the effect on noise. (Awaiting classic Matthias response "Nah, too much trouble, just wear ear protection")
Favorite channel on youtube - thanks for the great videos!
Thank you for the great demo. However I wished you also showed the change in static pressure at the outlet. For all the applications when you need to pressurise a space. Can you please show that in a future video. Only you can do it 😊
Matthias thank you I learned a ton from this video. Thanks a mill
I knew static pressure would be good here, same consept as in with radiators with High and low FPI (fins per inch)
I think it would be helpful to make the end of the curved veins perpendicular to the tangent of the impeller. If that makes any sense
Your next experiments should be on blade angle/design. A straight blower blade will yield the highest static pressure but airflow will not be as fast.
MrRedTux that was his previous video ;)
Joshua courtney, yup, but I think he just measured air flow, and not static pressure.
Good experiments. Static pressure under no flow conditions really means nothing for a dust collector.
Was this secretly a review video of those drills you put inside the cyclone?
This is why I love your videos so much!!! The day you stop learning is the day you stop breathing!! #NeverTooOld ;-)
"Restricted Mode has hidden comments for this video." not sure if you have noticed Matthias Wandel is now being censored by youtube if you have restricted mode on...
can you show in a next video how you made your static pressure measuring device please?
Is it an option to have multiple exits? My water pump has an enclosure around the blower in which the directions of the exits are in the direction of the flow. This 'forces' the airflow out (like with one exit), only now with many exits
Very informative!
good experiments here. I appreciate you doing this so I only have to watch. That's a lot of work ;)
Don't know what this is, what it's purpose is, or half of what you're saying. Lol but I always watch. 👍🏻
that was brilliant....
how about trying to out a two piece spiral housing part (2 "half circle" shaped ones) and place them so that there is one outtake hole at the opposing sides?
by the way... nice JUNK :P
Отличный канал!!! жаль что ни черта не понимаю язык((
Matthias, have you considered an impeller with more blades, that are thinner? i hear that is good at increasing static pressure.
Also, i wonder if you make the impeller taller/deeper but a smaller diameter, so it will have less leverage of load, but the similar surface area so it doesnt slow down as much under have load?
bgdwiepp it's usually the other way around, broader blades providing better static pressure but less airflow, and more slender blades providing the opposite
nope. you're got it backwards, think about all your high airflow fans (props, box fans, ceiling fans, etc), these all have basically the minimum number of blades because there is near 0 static pressure requirement. as the static pressure reqirement goes up the number of blades go down (car radiator thermofans, ducted axial HVAC fans etc).
a super obvious example is axial PC case fans, google image search "high air pressure 120mm fan" and "high air flow 120mm fan"
Build a blower, do the experiments. That's the way science works. Arguing is for academics.
Now that was interesting!
It sounds like an ACA P-15!
Make multi stage impeller!
Companies nowadays are desperate for research to make things more and more efficient and economical. It is less of quality an more of efficiency so the company can make more money
Genial
I would think that stator vanes like the once you would find in the compressor for a centrifugal flow jet engine would increase static pressure but I wonder if it's better than the housing.
turbomachinery.asmedigitalcollection.asme.org/data/journals/jotuei/926080/061034_1_f1.jpeg
So,,,,,,,, have you thought about making a scroll vacuum?? ;)
I love these kinds of videos. Such a great way to get intuition - just do a bunch of tests.
"To the pedantic types"! 😁 Thanks for sharing this experiments, Matthias. This kind of videos are one of the reasons why I like your channel
Dittos :)
Javier Castro I felt strangely pedantic after I watched
Great, now my lungs are cleaner... but my ears are dead...
7:53 Places "junk" inside the cyclone, aka 'Black & Decker' ;)
Ave would approve.
Actually those are both some garbage Canadian Tire house brand.
The Black & Decker pecker wrecker...
I like black and decker I am happy with my b&d impact,drill,vacuum, and circular saw
Black & Decker air flow wrecker.
Experiments ✓
Mean comment regarding drills ✓
Mean comment about "pedantic types" ✓
Yeah. We're definitely home.
The most efficient housing would be round in shape of impeller.
And gap between housing and impeller should be just the right distance.
Good luck
Now you have me curious about piping. Is rigid piping with smooth walls going to make a big difference over the ridges of flexible tubing?
From what I've read so far: flexible tubing with its ridges introduces a lot of pressure drop especially in any bends. Ironically in HVAC systems all the bends ought to be done with rigid smooth walled piping if possible but you can use flexible tubing for the straight runs (and nothing else) if you want due to its ease of transport and installation!
I think so.
It seems to me HVAC guys just run the flex stuff cause its easy and efficiency be dammed cause its not their money running the system.
Precisely. Not to mention leaky ducts leading to loss of heat/cool, and over- or undersizing equipment resulting in a host of other problems...
Flex will always bring more disturbance than smooth wall. In ducting its key to run your main through the house and then use as little flex as possible to connect vents in odd areas. We do see a lot of flexi duct being used now but you as the consumer have a voice. It has to do with how much you are willing to pay and proper planning for a project. Shortcuts always cost you more money in the long run!
I realize I am late to commenting on this video but was wondering if the shape of the cyclone matters? A lot of the commercially available cyclones are cone shaped with the exhaust at the top, where as yours is just a cylinder? Would the cone shape help push the air up towards the top and therefor decrease restrictions?
Thank you Matthias. Another very informative video.
You should try to get your hands on a blower for a small bounce house. I have one left over for my sons bounce house from when he was a little boy... thinking about making a dust collector for my sanders with it.
I have couple of ideas.
Test some variables:
Distance from lid to impeller.
Size of inlet of impeller.
Impeller with and without top ring.
Fix description:
eirflow->airflow
Moe->More
I will leave those up to you. To me, the answers to these are too obvious to warrant experiments.
We don't want answers, we want experiments.
The mob have spoken!
Since static pressure is the main limiting factor, it would be interesting to see how two impellers in series perform.
this is how most vacuum cleaners work, 3 to 6 platters stacked up in series.
Most car fans have a double inlet and a double wide impeller, mounted on a plate in the center. More parallel than series tho
Queensland, Australia has an interestingly shaped blower at the moment.
sucks to be there.
Haha... :(
Godfrey Poon I don't understand
Severe tropical cyclone Debbie...
Joel Pekkanen oh, jeez, okay
Thanks very much for this Matthias. I have worked on industrial dust collection/ air movement systems my whole career and i have seldom seen these sometimes counter intuitive engineering principles explained so clearly. Well done, you have a way with words (and video). Forget the pedantic types, I suspect most of your viewers, like myself, don't have any time for them either... aren't they first cousins to trolls on the evolutionary tree?
FANtastic. Oops, did I just write that?
Your work with these systems is amazing, and I am sure we are all learning something new with each experiment you perform.
I am so gonna try making one of these in the very near future.
Keep up the good work.
Yesterday while raking leaves, I had a brilliant idea! Why not make one of those into an electric leaf blower? Once I find a motor, I am going to do that! Less raking, and less awful 2 stroke exhaust!
You should look at air handler blowers. They use squirrel cages with the curves in the direction of rotation. Opposite of a water pump. It comes down to if you want high CFM or high Static
So now are you going to go back and optimize the wheel size for the dish washer motor and for static pressure? And correlate that back to the flat paddle test for motor output? As in what wheel dimensions and vane count is equivalent to a paddles length. I noticed the wheel you built here, under loads the motor some. Also what is the correlation in wheel thickness - diameter - center hole, dimensions. Me having a couple of those motors sitting around has nothing to do with these questions. :)
Hello Matthias,
First of all, I want to thank you for your extensive and educational videos! They are truly amazing! Very useful, especially now that I'm planning to make my own fan. Secondly, I have a question: Have you ever considered making a double suction blower? And if not, why not?
Greetings from Holland!
Very interesting, this has been very helpful thanks for a great video.
This was a really informative video Matthias. Thanks for making it and other ones like these! It doesn't seem to matter what topic you chose (wood, shop, home, camp, random) I always enjoy your style and learn something. Please keep making them!
you could try fewer or less fins on the fan
changing the shape of the fins
adding a dome or cone in the center
trying sharp or dull edges, since most fans have a thick body but sharp fin edges.
polished or rough / soft surface on the fins (a pc fan manufacturer used some sort of fleece on the fins to reduce noise.)
Dismanteling and old shop vac i realised the suction area inside the shop vac is like an rolled up smooth pipe. So i was wondering if cutting the outside of the propeller not square but roundish and having the housing area curved as well (creating the hollow pipe idea) would that be an improvement?
With a centrifugal compressor it probably is indeed most efficient to collect the air equally from every side of the impeller. This arrangement would be kind of like in early British and American jet engines which used centrifugal compressors - the air was pushed into ducts laid out around the compressor, and into the combustion chambers, and then through the axial turbine that powers the compressor. But, it would make for a rather complicated design with a lot of ducting, and the ducting itself could actually end up hinder the airflow more. Most centrifugal compressors used in turbochargers have the spiral or snail shell-like housing, so probably the simplicity from having one outlet outweighs the advantages of multiple outlets set equally around the impeller.
I had a similar issue trying to lengthen a AC venting hose in my bedroom. It came with like a 10ft hose, and I tried to add another 8 feet or so, and it just couldnt evac the hot exhaust worth jack all. Go back to the factory length and it was cold, add my extra 8ft, the room barely got cool.
okay here's my scenario it doesn't really involve joyner's planers or table saws or any of the wood dust collection that you're dealing with my situation is dealing specifically with dust collection from a four and a half inch Grindr using 36 Grit sandpaper and it produces an enormous amount of dust so much it covers everything in the shop and I guess I was just trying to find something that had an enormous amount of suction that could deal with the situation.
Stupid idea may well be stupid ... but here goes ...
What would happen if you reduce the impeller height by half, and have the fins on the bottom going backward, followed by roundel of plywood, then a second set going forward, topped off by another roundel of plywood, with both spinning on the same axis, either on a common shaft, or a shaft-within-a-shaft arrangement (which would be a nightmare to engineer) ...
The reason for asking was Dyson at one point at released the DC-O1, a washing machine that had a split drum that contra-rotated, which supposedly was more efficient in washing clothes ... (although was withdrawn from market due to problems ...) ...
I presume that the airflow upwards would be very chaotic, possibly increasing the power load, whilst negativly affecting airflow velocity, and dynamic pressure, but it would be fun to see whether I'm right, or wrong ...
I was planning to make an heat exchanger, and doing some guestimate, I figured that the pressure was an huge factor, and caused an huge flow loss. I'm still looking for some inexpensive blowers for it, and I can't find anything with enought CFM and pressure. I might be forced to actually stack two, one on the intake and one on the outtake, just to get enought pressure... A royal PITA for sure.
Have you had a look at using small splitter vanes between the leading edges of the blades? It looks like a very easy thing to add in and apparently helps with static pressure of backward bladed fans. (see "Impeller Treatment for a Centrifugal Fan using Splitter Vanes - A CFD approach" for more info)
Would your hand holding that piece of wood closer to the rotor have been what was restricting the flow a bit?
I just watched your chicken wire filter from 2016 and wanted to let you know about the centrifuge design. Sure enough a quick search and it looks like you're already on top of it!
Why do I know about this design? I wanna see if it's effective for cleaning impurities out of the air during a dust storm - Say in the desert or on mars. :D
I have no dust collector because I ussually do woodworking outdoor. I have no skills on building this machines. I do not have those measurement instruments... but, I'm engineer, I do woodworking... and enjoy like a kid with this kind of videos. Thanks!
Now remove veins from the impeller and I bet you increase airflow and noise. I'm not sure what you do with pressure, and if you put the veins at a greater angle you'll increase pressure.
Restricting the size of the hose would also improve air pressure, maybe you could experiment with that, I thought also something similar to a beater bar to break up the path of sawdust/chips like an upright vacuum uses would help with air flow without increasing motor size and/or suction either, also would agitating the air flow by interrupting suction possibly by using an elliptical blower or one way valve make a difference? but as a last resort wouldn't just increasing the brute force of the hp/amps of the motor help with atmospheric pressure?
I'm sure this is an obvious point, but they teach blower design in mech engineering disciplines and there are comprehensive blower design text books on this subject already. What there _isn't_ is a decent software application that takes those calculations and puts them into a reasonably priced design package...similar to woodgears.ca/gear_cutting/template.html . ;-)
Hi Matthias, i've built a dust collector myself With a cyclone dust separator but i have a problem, The impeler keeps clogghing with wood chips mostly when i am using the thiknes planer, i think the problem it îs în the cyclone, i put in the center of The cyclone a pvc pipe of 110 mm în a way that îs a bit lower than the intake of The cyclone, What do you think it needs to be shorter?
I'd always heard that something like a shop vac would make a lousy dust collector as what you'd really need is the high CFM of a dust collector fan, but this data seems to indicate otherwise. Is that advice I've heard true or am I misunderstanding something? Thanks.
Your conclusion in the middle part of the video, depends on whether you are sucking or blowing. It also depends on whether you actually want to do anything with the air you are shifting. Since your blower is at the end of your process, you don't care whether the air goes after you have propelled it.
Wonder if a larger diameter cyclone can would greatly benefit the system? I'm now going to look at changing my hose system to use a few short pieces of flex interspersed with solid sections of pipe. My shop layout can support this, YMMV.
the difference in the sharp edge in the spiral housing comes with pressure build up at the blowing side, as does most of the benefit of the housing itself.
that being said, since you have made a rather robust blower, wouldn't it be better to blow trough the cyclone instead of sucking trough it? this would mean getting dust in the blower but it looks like it can handle that, plus the dust wouldn't pile up in the high flow areas. building pressure is easier than removing it, since the air needs something to push against to impart energy, building 0,3bar abs requires about as much energy as building removing another 0,1bar from that, given a closed volume. then again it might make 0 difference given the large restriction of the hose and this device working more on mass flow than pressure (though as you pointed out, pressure is still important)
Talking about centrifugal force is just like talking about the Coriolis force or the force of God; it's just a matter of convenience even though we all know that they don't really exist in any real sense. Not a problem.
How about the dimensions of the impeller? If you resize it to have a bigger diameter and smaller height. (if you think it as a cylinder), what effect would that have on the pressure?
In other words, Is it better to make an impeller with a large diameter or a tall one to have lots of static pressure? I'm guessing sacrificing height for diameter results in less airflow but more pressure.
I'm sure it's been said but I would love to see a comparison of differing lengths of solid pipe and flex pipe with the same length run. I'll be honest most of this video was over my head but I'm sure once I'm working on a comparable project I can refer back to this and get more necessary information.
You should look at making a muffler for that loud dust-collector! It'd be neat
I'm curious if a completely smooth hose would make any difference compared to the ribbed hose you have. Also would a straight tube/hose be any different than one that has a lot of 90 degree turns?
دائما ما تبهرنا انت مبدع جدا وانسان خلوق اتمنى لك التوفيق ❤
if you wanted a LOT of static pressure it seems you would need a really big blower. but noise and power consumption would obviously increase, and its less efficient for the same motor size. Im wondering if there is a series or parallel configuration where you could run two smaller blowers, and generate the same static pressure of a single large blower. But both motors draw less watts combined than a single motor.
just a question, what if you somehow included the Tesla Valve and/or turbine in to the equation, would or could you produce a more efficient outcome??????
have you tried making a stater? also, this should work differently when on the exhaust port vs on the intake for a pressure reading. considering your readings i would make a wheel that more closely matches your system, thinner and larger diameter. should give the benefit of having more differential pressure and less noise. but you wont have the mass flow when you disconnect the hose ect.
Now the only thing left to make a perfect dust collection system is comparing the effiicencies of various cyclone shapes, cylindrical, conical and sizes (and inlet and outlet pipe shapes and sizes and depths)...
Hi,good tutorial,I just have a shop vac on every machine,never have a problem.thanks again.from Australia.
Good thing I don't have time and space for building stuff right now so I can watch the mistakes of others ... :D
Good video, though!
I made some experiments with cyclones and airflows myself and came to an interesting conclusion:
The diameter of the cyclone is surprisingly irrelevant. I thought a smaller cyclone would make for faster rotation and thus for more resistance but I tested three variants from 400mm to 590mm diameter and they were pretty much equal. Also there wasn't much difference in their ability to catch the dust. So I went ahead and ordered one of the totally overpriced dust deputies (125mm inlet version) and was really surprised: With that cyclone the air flow almost doubled. I don't know why the air in there rotates so much more "efficient" but it has a lot less resistance and I don't see a difference in it's performance yet. Still most of the dust goes into the bin. So it seems to be a good product, but the price... nah. But if someone here reads this and is thinking whether the effort of building one on your own is worth it: Yes, it is. Marius Hornberger has some videos about it. Hope this helps. Took me several days to build all those cyclones. For separation it doesn't matter what design you chose, but for airflow: Use the cone shape. Wish I could explain why.
Rainer Zufall, Marius, and Matthias have explained this in older videos to some degree. Also Phill Thien's website explains why the baffle has less air flow, but keeps the dust rising out of the collection bin when it gets almost full. Basically, the baffle creates a positive pressure lobe at the center, causing a lot of resistance. Well, that's the best way I can explain it.
I only know all the videos from the first two :) At least I cannot recall any comparison but they have a lot of videos and I have a bad memory so I may be missing something. But today I want to add: Just in case someone wonders how good the dust deputy is at separating fine dust from 120 grit sanding: It is pretty much 60-70%, which I think is really good. Did a lot of sanding today with my drumsander. 30% goes to the filter but considering we are talking about really fine stuff I think that is good performance. I wonder if you can get more performance with another setup. With the good airflow a two stage cyclone would be possible but will it really help... hmmmm.
Power equals volumetric flow times pressure.. So yes, to get optimal power efficiency from your system you need both.. :-)
Hahaha. Was that a jab at Mastercraft and what appears to be B&D? "I'm going to put some junk inside the cyclone."
Anyone know how to choose the best angle and curvature for the backward curving blades? Is a circular arc shaped blade optimal or should the curve become less tight going from the center of the impeller to the outside?
great video ,,,, explains a lot , the length of flex hose will probably effect it as well ,,,, seeing that the hose had the biggest resistance ,,,,, would be nice to see the resistance from 90 deg elbows and 2- 45 deg and flex pipe like for a full shop dust collection set up
The manufacturer of those tools are probably hate you right now because you said you were putting "junk" in the cyclone. Pretty funny joke if it was intentional.
Just excellent video ! Got all the ans. to my questions, best experiments
Cool, so how to increase the static pressure efficiency? How do commercial vacuum cleaners do this so well?
That increased noise when you closed that gap was just the wooden plank vibrating like a diving board. I don't think that noise would be there if that profile was rigid.
Awesome video, have you experimented with water pump impellers? Do you think you will have different results with a water pump?
Could you please please try adding some veins to it! It's suppose to increase the pressure by converting the kinetic energy to potential energy but I've never managed to wrap my head around it.
Can you tell me what should be the blower capacity in terms of horse power in relation to the workshop size.
Mine is 15 meter X 4 meter?!
The spiral housing is restricting the output of the fan. So of course it sucks more without the spiral housing. However, if you want a blower, then you need to conduct the same experiment and test the output wind speed rather than the inlet air speed.