More suck from a shopvac: Effect of hoses on dust collectors
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- เผยแพร่เมื่อ 29 ต.ค. 2020
- Measuring air flow rates with different types of hoses hooked up to my shopvac and my dust collectors. What type of hose you use makes a big difference in terms of air flow.
woodgears.ca/dust_collector/ho... - แนวปฏิบัติและการใช้ชีวิต
What I love about you Matthias is that you set out to just build a new router table cabinet. You did that, it was done. Someone asked why not just use a shop vac and you took the time to explain why. And then, with no one asking, you decide to go deeper and explore suction power of a shop vac because your dust collecter preformed better than expected. So many would just take the W and move on, you were interested in why and took the time to show us. Thank you. Because frankly, you've already explored the advantages of why built in dust collection is the choice for you (frankly, suction is low on reason why I've done it to a few of my tools).
So thank you. This feels like such old guard youtube. Not enough people do videos merely for experimentation especially when the topic has virtually no chance of going viral.
Couldn't agree more! I feel like TH-cam's structure and algorithms have pushed most TH-camrs away from making quality content. It's really quite sad to see how many talented TH-camr's skip out on making UNIQUE videos like this out of fear that TH-cam's algorithms will crush their subscriber or view counts.
See, these are the questions that I didn't realize I needed the answers to, but I'm really glad that I have them. These kinds of videos are super interesting to me, thanks for sharing.
Thanks, Matthias, you've just convinced me that I did the right thing in buying a little shop vac to connect to the small hose on my ROS rather than using an adaptor to connect to the four inch hose on my big dust collector that I use for the thicknesser/planer and table saw, router, etc. It also has a power socket for the ROS (or Festool Domino) so I still get hands-free switch-on like on my big machines which are all supplied via a multiway socket connected to a vacuum auto switch box. I always thought that there was a reason why so much dust was present when I disconnected the four inch adaptor, and you have demonstrated the answer in another of your 'Investigative Science for Woodworkers' series.
Thank you VERY MUCH for this video! Not only was it educational and fascinating, it was very useful for how I use DC in my shop. I just bought a new 20-foot hose for my shop vac. I paid extra for a wider hose and now I'm really glad I did. Also, I was considering adding a cyclone to my cheap DC, but not anymore. I love how you back this stuff up with actual numbers and not just opinions. Great job, sir! 👍🏼
Having tried a few different methods/cyclones/machines now after pouring over information on such systems over the last few years, this was invaluable information. Thanks Matthias, your experiments and data gathering is every bit as engaging as your builds.
This video should be required watching for any potential electrical engineering students. The analogies to current, voltage and resistance are just too perfect. Even the voltage drop on long thin gauge wires vs heavy gauge can be explained.
Electrical resistance analogy would also explain "what if we put a small section of smaller hose with a bigger hose?" type questions people are asking around here.
That shouldn't have been as fascinating as it was. Thanks for taking the time to do it because I can now make much better use of my shop vac systems.
The smoothness of the inside of the hoses probably makes a big difference too, especially for smaller hoses where turbulence from the walls of the hose will take up a much larger part of the cross-section.
Thank you for this clear and in-depth exploration of the effects of different hoses and cyclone add-ons. I’ve been trying to decide on an approach to dust collection in my small shop and this analysis will be a factor in my design.
Really appreciate the insight. Answered a few questions I had and lost I didn’t know I needed to ask.
Thanks for taking the time to experiment on this! Very useful data that will help us take better decisions on our dust collection setup! Really appreciated! Cheers!!
I don't know why I haven't made this connection before, but watching you discuss the differences in your technique and the results gave me flashbacks to watching Doc Brown in Back to the Future. You are sort of a good guy mad scientist ...
very useful! it is hard to understand all the different information out there about different vacuum types (shop-vac vs. dust collectors), hose types, etc. Nice to see it all presented in one practical use. Would love to have more insight in the future about why we use both types of vacuums in a workspace.
A great visualization of fluid dynamics! Thanks! Before the Internet, we used to use Thomas Glover's Pocket Ref to get the flow rate drops in plastic pipe so we'd know the right size pipes to use in moving water for our rainwater and orchard systems. Now it's easy to look up online though.
I'm trying to cobble hoses to put a concrete shop vac outside and connect to a 7" dust shroud for an angle grinder with 7" diamond cup. Grinding concrete with regular shop vac captures most but not enough dangerous dust. This video perfectly explains why the small 1 1/8" shroud port is not adequate. Even with a 4 1/2" cup and smaller grinder it is barely adequate. Now time to use some ingenuity to get a better result.
I have never subscribed before but you are now the first!
I have linked together in series two wet/dry vacs for extra suction and for use on wet carpets, works great. Love you Mattias!
Awesome stuff, I’d never do these tests myself but greatly benefit from you doing them. Thank you so much for making me smarter
Hey MW, I'm standing up for the dust deputy which is in line with my shop vac. Although I might lose some efficiency with the airflow I gain usefulness as the vac works without clogging the filter for a significantly longer time. So, I'll take the losses for gains anytime.
Keep making this type of content, it's so interesting.
Cheers Joe from down under.
That's exactly what he says in the video.
He says a shop vac only has a very small penalty when using a dust deputy cyclone....where a dust collector loses 50% when you add a cyclone.
You hardly notice any difference when using a cyclone with a shop vac...it actually improves it in the long run because the filter doesn't get 90% of the debris.
Currently tossing ideas around about building a dust collector from a 2.5hp motor. Very informative video as always!
Thank you so much for doing this, I have been wanting to see these tests for awhile!!!
Thanks for the video.
I have known the smaller shop vac hoses were not good for air flow compared to the 2 1/2in hose. I appreciate you spending the time to show the measurements. I do not have an airflow meter.
The flexible hoses have a lot more pressure drop than if they were smooth on the inside, but we all need to be able to easily flex our hoses around the shop.
I was expecting the cyclone to have a larger impact. Interesting.
Dave.
Thank you, I've learnt a lot from this... Bought 10m hose online, connected it between my belt sander and a domestic vacuum cleaner, then wondered why most of the dust was escaping from the joint between the hose and sander... Now I know why!! (Yes I'm going to shorten the hose and buy a shop vacuum when I get around to it!)
Great tip. I recently added a Dustopper to my shop vac based dust collection but the airflow was terrible and it also wasn't separating well. The issue turned out to be the 1 1/4" hose which came with the shop vac. Swapping with a 2 1/2" hose made a huge difference in suction (so far only assuming the issues with the dust separation were due to the low airflow).
This guy is so smart, explains so well. Starts with "I wrote a Python script, to control it"
Very helpful and informative! Thanks for taking the time to do all this work and share it for our benefit.
Very similar to what we have to do for the Fire department. Using unique friction loss coefficients per hose diameter for a given length of hose, as well as accounting for miscellaneous in-line devices such as valves, wyes, fittings, we can then calculate total friction loss to determine which pump discharge pressure will be required to deliver the optimum nozzle pressure. Different nozzles (deck guns, smooth bore, & fog) have specific PSI and GPM ratings.
finally found a video to prove me a point what hose size is better thanks for the video!!!
This was fun. Thank you!
All I was thinking at one point: “that’s a MESS of hoses now...”
I have the same craftex dust collector. I noticed a huge performance boost when I increased all my hoses to 4".
I use a Veritas cyclone lid that fits over a garbage can and has 4" hose connections. I still get good flow with this. I haven't measured the flow, but it gets all the shavings from my planer.
My old setup was a shop vac with 2.5 inch hoses and a dust deputy cyclone. This did not work well at all when I swapped the shopvac to the craftex, but the 4" hoses made a huge difference.
This answers "why" to all of my questions. Thank you!
BUT >> High Flow Rate with Low air velocity will not carry chips thru the hose. / / / So it would seem you have only done a wonderful job of starting the investigation into a fascinating and important topic "Things that Suck". / / / What Velocity is required to move objects of different sizes . . . . the small hose on your small Shop-Vac will pull a marble uphill . . . . not so much with the bigger hose. . . . . GREAT STUFF !
You probably have a point but I would argue that with dust / chips it is mostly self correcting.
Imagine a hose with a thin buildup of dust along the bottom
Now imagine that the buildup grows to the point that the cross section is cut in half, meaning the velocity goes up by double.
Now there is enough velocity to pull the chips and dust out and you get a "dam" of sorts that runs thru the hose and clears it out.
Then the cycle repeats
this is all basic fluid dynamics good job showing off the Hazen-Williams equation in action.
It's exactly the same as designing a vacuum system for the lab - keep your connections as short and wide as possible. Bends are bad, too. And the smallest diameter in the system will throttle the entire system. Very interesting to see it in action. Thanks.
@John Ford, if you're running 6" diameter duct and taper it down in 4" diameter runs to your machines, will the whole system behave as though it is 4" duct, or will it be some intermediary between 4" and 6"?
@@Exodus5K it will be some intermediary, the section of 6" will count like a somewhat shorter section of 4". The shorter the 4" runs are in proportion, the more you will profit from the 6". Sadly the exact math is beyond me, but there are flow calculators online that may help.
John Ford: Very good recommendations overall... BUT one thing you have to add: An excessively large diameter can cause problems with heavier dusts collection, because a minimum velocity of the dust-ladden air is necessary in order to prevent dust settling. Some dusts can have a tendency to stick together or form agglomerates, with the result of partially clogging the hose or pipe. Therefore, some extra numbers are needed to best design the optimum diameter. In addition to that, the kind of hose corrugations has a large impact on pressure drop. So, for a complete design, some attention to the internal (lack of)smoothness of the hose is needed too. In my experience, the standard short radius PVC elbows are the worst; I learned how to bend PVC pipe into gradual large radius curves using hot sand and a hair drier, and improved my piping considerably!
Best regards.
@@alfredomarquez9777 In wastewater collection this theory is called minimum scouring velocity. The idea is directly applicable here.
Also, agreed on the consideration of smoothness of the interior of the hose/pipe as well as bends.
@@Exodus5K I'm not sure my vacuum line experience translates so directly to dust collection because we're in a different flow regime. But in a vacuum system a single small tube will reduce the flow in the entire system. Keep in mind that the vacuum systems I deal with are small (2 m total length, maybe) compared to a dust collection system. The real advice is to avoid sharp bends and narrow throttles.
You really answered my question about the fact putting a cyclone, thank you!
I wish more TH-cam videos were like this one. Why? For a start, no freak'n background music! Voice is clear and understandable! Camera is pointed 90% at the subject of discussion, not at somebody's yapping face! It gets to the point! No time-lapsed assembly ad nauseam! Good video.
MW. The man who can make anything interesting. Because he knows everything.
And if he doesn't know it, he'll try to find it out.
That's how a good engineer does!
Thanks. I was going to use a cyclone and pool hose with a vacuum but recently wondered if a dust collector would be better. Turns out that would be a waste of money and a step backwards. Great video.
Thank you. I have just been wondering if I would get better results with a bigger hose and you have saved me the effort of experimenting. I will buy you a beer next time you are in Melbourne , Australia
So much good info to digest, just about to build my dust collection system.
Quite an interesting experiment, and with some very informative outcomes.
It would be interesting to see how you could design high pressure blower vs high airflow blower.
higher velocities = higher pressure
closer tolerances = higher pressure
larger blade area = larger volume
pressure x volume = power
small blade + high rpm = high pressure
large blade + low rpm = large volume
large blade + high rpm = large volume @ high pressure = tons of power
This experiment literally just proved that velocity and static pressure are not equal
@@LateNightHacks does blade shape have any impact that you are aware of? So in other words, assuming no design errors a simple back curved fan blade could be made to a shorter height and larger diameter and spun with a higher 3600 RPM to get more static pressure?
Meanwhile a taller fan assembly spun at 1700rpm would be quieter and probably provide more airflow but at a lower SP?
@@gordonbowe interesting question- if you find out, please let me know
Money
Awesome lil look into hose tech there dude. Cheers! Xx
Very good presentation. I'm an engineer and you nailed it.
Always love your experiments, thanks.
I use my shopvac with with a dust stopper and 2 1/2” hose. I removed the filter and ran the exhaust outside. Huge difference.
That is an impressive collection of hoses....
Really interesting results, dude! Thanks a lot! 😃
Stay safe there with your family! 🖖😊
Great job! Thanks for sharing theses experiences.
I have a 2000 watt shop vac with a 2"hose.Found out the first time it clogged that it fitted onto a 1" pipe into the vac body.Made a few adjustments and now it can lift anything put in front of it.
VERY INTERESTING! I think of all CFM tests of when I built my pipe organ... Crazy
Cool did you videotape it
@@mookfaru835 Yes, I recorded it... In my channel. Thanks!
Ultimate Canadian hoser video. You are the best!
Really enjoyed it. Thanks for doing the work & sharing
Enjoyed a lot- Also like the text-over to admit that the people will doubt basic physics ;-) . Checking the effect of bends vs straight tube would be intersting
I like the idea of switching to a thicker hose on the shop vac because it is a very simple solution to increase the suction power
Keep up this informative work, Thank you for the efforts.
Wow. Very helpful video. Looks like I'm ordering some new hoses.
We applaud your sacrifice for science.
These videos are awesome. Thanks for sharing this.
I think you are right about the cyclone penalty being more for a high-flow system, because it results from accelerating the air to make it spin, and there's more air to accelerate.
In a small DC like your craftex, putting a Thein baffle inside (rather than free standing) may cost the least flow because the air already circulates there, and you are simply using that circulation more effectively.
I’ve made a DIY shop VAC with a vacuum motor (included fan and speed controlling circuit) with bigger air hoses and 2 stage filters (cyclone and paper filters) and it works very well.
The old vacuum machine didn’t work well by household design’s on/off button.
Science! I too enjoy finding out stuff like this, even if I'm never going to directly make use of the knowledge for this specific application.
I have a background in chemical engineering. Some other things for you to look into is Slot Velocity, Particle Carry Velocity, and Head loss via hose texture.
It would be nice to see a comparison between flexible hoses and solid pipes. Especially the impact on different lengths.
American: Its too difficult to use both Imperial and Metric measurements
Canadian: Hold my poutine
Actually, all the whining I see regarding Imperial/Metric seems to come from Europeans.
Except that both Canadians and Americans use both customary and metric measurements. Depends on the use case.
inches are metric anyway. Defined as exactly 2.54 cm :D
Metric should still be taught in school.
@@GreenAppelPie You can bet anybody taking science classes like chemistry and physics will learn it. And science and engineering is where it shines so that makes sense. I don't want to be buying 229mm pies. I see a place for both systems at this time.
Love this video always interested in what's best to do vac Vs blower etc
I think that's great information. I think I'll just stick with the shop vac for now. Thanks!
Thank you very much for explaining all of this. Amazing!
Wow very interesting
I'll be sure to think about this type of stuff in the future now that I know how much effect it makes
Nice to have the shop to run these experiments.
Hi Matthias, excellent video. Hope you still monitor these old comments.. I feel the there needs to be another layer of analysis added here: what is the air velocity per pipe per machine, because surely that is the fundamental physics that drives dust or chip movement in the hose? You can maximize volumetric flowrate by increasing the pipe diameter to where you basically have no losses in the pipe, but you'll also have (near) zero velocity and no chip/dust movement. Air speed transports particulates, not pressure or CFM's.. But you know that.
Then you'll have to test/experiment to determine min velocity required to say lift/suspend a typical planer chip vertically as baseline for comparison... Good luck!
Been looking for info on this. Thanks!
This is very valuable information, thank you very much!
Thank you so much, wildly detailed and so helpful!!!
Very interesting, I just got a 5 gallon bucket lid system to test out, because it's sure to beat the 0 CFM/broom method I've been employing for far too long. Matthias will have me dumpster diving for HVAC motors soon I'm sure...
Well Matthias I’m blown away - don’t think I’m ever going to be dust free 🤪😂
i use a home cyclone vac with the beater bar and belt removed on each of my scroll saws. they work great. but in a 10x10' shop you have to keep everything compact.
Excellent demonstration!
I love MW's experiments above all other "woodworking"videos....
Awesome video. Love this style
Hi Matthias, great video! I was curious as to how you get the CFM output using your anemometer?
And I’ve figured it out:). A little googling and lighting up some brain pathways that haven’t fired in a long long time. This is cool- I’ve wanted to test out the effect of dirty vacuum filters and what happens when you use a fleece bag etc...
Dang it, now I need to buy all new hoses. Lol Thanks for all the info.
Very useful, thanks Matthias!
Well, another aspect of CFM is the sustained force that a motor has behind the volume of air being moved, which is often not considered but can be the most important part of pulling things into an opening or being able to pick something up. My shop vac has around 150 CFM, but a low amount of sustained suction, so it cannot hold a candle to some other vacuums out there. I worked a job where we had a truck mounted tri-lobal vacuum, running on the PTO of the truck. It could pick up carpet off the carpet tacks, or pull a baseball all the way into the reclamation tank! it only had 200-220 CFM, but holy crap it never lowered in pulling power even when the opening was made smaller, it just pulled harder.
Love the experiments!
The load is the main obstacle. In fact, matching the load to the power source is the key for efficiency with most systems (not only shop vac).
First thanks for all your videos. My question is have you or have you heard of anyone trying to increase the size of the inlet right at the source? Let’s say on a shop vac. Going from the 2” to a 3 or 4”. And then also some how increasing the size of the filter area or even eliminating the internal filter in the shop vac and putting one larger one externally? Let me know. Thanks again for all you do for the woodworking community.
COOL!!!
Outstanding info, Thanks!
Awesome what knowledge can be gained from a little effort. Much appreciated! I would luv to know how this stacks up to strait pvc pipe plumbed in with blast gates 45 degree bends etc...
that was very useful for me ;-) thank you very much for this test
well this was educational. I've often wondered if using a smooth hose would help at all, vs the ribbed hoses.
This was good and concise. Thank you.
On an older 1HP dust collector, I added extensions to the vanes on the impeller. That dramatically increased the static pressure. I was then able to use smaller hoses and still get a decent CFM. However, the one major drawback of the vane extensions was that a massive increase in the noise the tool made. It was very high pitched sound, which the family told me was unsuitable for my basement shop
if the blades get too close to the housing, it gets loud. You's need to make the housing bigger too.
@@matthiaswandeloh absolutely, but then I'd need a larger motor too. While I tell my kids "buy once, cry once", I don't do that myself
That is indeed very useful, thank you.
I would like to see if there is a difference between a flex hose laid out straight and one that has lots of bends in it to see if that makes any difference. Thanks!
Instead of extending the water column, you could trap air in the low pressure leg and by that measure much lower pressures with a short water column (e.g. carburettor adjustment etc). The trapped air acts as a "helper spring" but the reading will not be linear.
A lot of people add cyclones to their dust collector like your big one. But they use much bigger cyclones than your homemade cyclone, so the CFM penalty is much less severe. Just remember that larger CFM requires a larger cyclone.
Very interesting - thank you for the video! Would like to see the effect that putting 10' - 20' of PVC pipe inline with the hose would have on airflow... thinking of piping up my workshop with PVC in the ceiling so that my shop-vac powered dust collector w/Thein baffle could be moved to the next room.
The ridges inside the hose are a huge resistance. A smooth hose would be an interesting test.
I think applying the various choices is more useful than the experiments. Could you optimize each system. Hose type and length for each application?