Thread Number: 34069  /  Tag: Brand New Vacuum Cleaners
Bypass motor with most airflow
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Post# 369242   3/26/2017 at 08:24 (393 days old) by sebo4me (Cardiff)        

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Which vacuum cleaner with a bypass motor has the most airflow?

Post# 369244 , Reply# 1   3/26/2017 at 08:57 (393 days old) by vacerator (Macomb Michigan)        

systems us the Lamb 2 or 3 stage bypass motors. Some for very large or commercial installations even use two motors.
If you mean portable cleaners, then probably large commercial types.

Post# 369253 , Reply# 2   3/26/2017 at 10:52 (393 days old) by sebo4me (Cardiff)        

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What about domestic cleaners?

Post# 369260 , Reply# 3   3/26/2017 at 14:10 (393 days old) by wyaple (Pickerington, OH)        

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Just a clarification: did you mean a bypass motor in a domestic cleaner or a "clean air" machine that has a bag first orientation?


Post# 369262 , Reply# 4   3/26/2017 at 14:17 (393 days old) by sebo4me (Cardiff)        

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A clean air motor in a domestic cleaner. Bag before motor. 🤔

Post# 369265 , Reply# 5   3/26/2017 at 14:35 (393 days old) by wyaple (Pickerington, OH)        
Ah, That's What I Thought You Were Asking...

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The Hoover Tempo Widepath has a whopping 80 CFM at the nozzle and only costs $70 from Amazon at the moment.

I've had mine since 2012. EXCELLENT cleaner for carpets. Impossible to beat at several times the price. I only use cloth HEPA bags.


Post# 369268 , Reply# 6   3/26/2017 at 14:55 (393 days old) by sebo4me (Cardiff)        

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That is impressive!
Are there any clean air machines that can reach 100 CFM at the floorhead? Or is that stretching it a bit?

Post# 369280 , Reply# 7   3/26/2017 at 17:34 (393 days old) by Mike811 (Finland)        
Nilfisk GM80

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My Nilfisk GM80 with two turbine industrial GMI motor (1000W) pulls huge airflow. Almost 9 on the baird airflow meter. And it is measured at the hose end.

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Post# 369281 , Reply# 8   3/26/2017 at 17:51 (393 days old) by Mike811 (Finland)        
Nilfisk GM80 CFM

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I forgot to say that in cfm it is slightly over 100 cfm

Post# 369283 , Reply# 9   3/26/2017 at 17:55 (393 days old) by wyaple (Pickerington, OH)        

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Yeah, I'd think that 100 CFM at the nozzle would probably be something of a record for a clean air machine.


That Nilfisk is pretty cool! A Baird 9 is about 108 CFM at the end of your hose. BUT, measure it once again at the nozzle end and watch the CFM drop an average of 20 CFM. :(

What does that Nilfisk pull on the Baird meter with the hose stretched out straight?


Post# 369284 , Reply# 10   3/26/2017 at 18:11 (393 days old) by Mike811 (Finland)        

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Oh yes cfm will probably drop when measured from the nozzle :(
I haven't measured when the hose is stretched out straight.
If I then get over 9 I would be stunned :)

Post# 369286 , Reply# 11   3/26/2017 at 19:41 (393 days old) by dc (Arizona, USA)        
Miele S7?

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Vacuum-direct stated the Miele S7 has 141 CFM of airflow, but I have no idea where they measured that. I find that hard to believe. I have one though, and I can say that it does suck crumbs in front of the vacuum on hard floors with the brush off. Most other clean air vacuums with a 12 amp motor should be able to do that though, right?


Post# 369290 , Reply# 12   3/26/2017 at 21:17 (392 days old) by wyaple (Pickerington, OH)        

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Yeah, that'll be a reading directly from the motor. What manufacturer would ever want to post a much lower nozzle number? :)

Even Aerus only posts out-of-the-vacuum motor specs, like the Guardian Platinum 505 Airwatts, 116" of water lift.


Post# 369301 , Reply# 13   3/27/2017 at 08:07 (392 days old) by sebo4me (Cardiff)        

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Maybe I should have said most airflow at the hose.
Would be good if manufacturers were forced to list the CFM at the floorhead.

Post# 369304 , Reply# 14   3/27/2017 at 10:56 (392 days old) by wyaple (Pickerington, OH)        

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In my small collection here's the best hose measurements based on type of machine.

HOSE MEASUREMENTS (with HEPA bag/Filters installed)
Dirty air upright 120 CFM = Kirby Sentria II
Clean air upright 115 CFM = Panasonic MC-UG589
Clean air canister 95 CFM = Electrolux Olympia One (new vinyl hose)
Bag less upright 75 CFM = Dyson DC14 Animal

And yes, it would be GREAT if manufacturers were forced to list the hose and power nozzle CFM. But that will never happen because the world would explode. :)


Post# 369305 , Reply# 15   3/27/2017 at 11:14 (392 days old) by sebo4me (Cardiff)        

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Haha it would 😁

The Panasonic has great airflow for a clean air motor.
That could be the highest!

Post# 369381 , Reply# 16   3/28/2017 at 05:48 (391 days old) by Mike811 (Finland)        

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Just stay away from the bagless vacuums...

Post# 369382 , Reply# 17   3/28/2017 at 06:38 (391 days old) by sebo4me (Cardiff)        

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Interesting Mike.

So is there any way to manufacture a cyclone unit that will have less impact on the restriction of airflow?

Post# 369385 , Reply# 18   3/28/2017 at 08:09 (391 days old) by Mike811 (Finland)        

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It's hard to say. Single cyclone vacuums with very powerful motor has most likely the most airflow.
I have to make a video with my Electrolux UltraFlex. It's designed so that I can measure airflow before the cyclone. With cyclone it has 4.5 airflow, but motor in it is 2100 watts so I guess it needs it.

Post# 369400 , Reply# 19   3/28/2017 at 11:22 (391 days old) by wyaple (Pickerington, OH)        

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What a drop in airflow from your "bag saver"! From a 6 to a zero. That would mean:
93 CFM (a "6") - 46 CFM (a zero) = 47 CFM loss due to the cyclones.


It's pure physics. Cyclonic machines will always sap airflow because they make the air "do extra work".

Dyson DC14 cyclone loss is 43 CFM
Dyson DC25 cyclone loss is 45 CFM
Hoover Windtunnel 2 Pet cyclone loss is 58 CFM
Hoover Windtunnel MAX cyclone loss is 48 CFM


Post# 369401 , Reply# 20   3/28/2017 at 11:41 (391 days old) by Mike811 (Finland)        
Airflow = cleaning performance

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It was clear to me that the bag saver steals suction, but shocking was how much. There is many nice bagless vacuums what I like (like the Shark Rotator), but this just make me think. I have tested all my vacuums with deap cleaning (shag rug) and airflow is straight related to the pick up performance. Higher airflow vacuums just deep clean better.

Post# 369471 , Reply# 21   3/29/2017 at 00:19 (390 days old) by sebo4me (Cardiff)        

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The Baird meter has shown that bagless cleaners have low airflow due to the action of the cyclones yet the Shark gets a Silver award from the CRI which is a high level and the Shark Powered lift away gets a B rating for carpet pick up in the EU, the ratings go from A to G so that is a high rating too.

I'm a little confused. How can a cleaner with such low airflow still get a high ratings?

Post# 369474 , Reply# 22   3/29/2017 at 02:18 (390 days old) by sebo4me (Cardiff)        

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I agree Sebo could update their "Domestic range" and add more features but whether they will is a different matter! :)

I do like the E3 Premium. If I were to choose between that and the Miele PN model i'd choose the Sebo.

I understand Go Vacuum stopped selling Miele in favour of Sebo. There is a reason why :)

Post# 369531 , Reply# 23   3/30/2017 at 02:23 (389 days old) by Mike811 (Finland)        
Testing it

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So I made a video showing how much the cyclonic system in the bagless Electrolux UltraFlex steals the airflow.
First I measured it with the air going through the cyclone.
Then I measured the airflow bypassing the cyclone.
Cyclone in use result was 5 and without it 8. So 85 cfm trought the cyclone and 104 cfm without the cyclone. Drop was 19 cfm. Not too bad in this vacuum cleaner.
I also tested the turbo brush spin speed. This needs airflow and suction. There was also drop in the spin speed with the air going through the cyclone.
Next is going to be deep cleaning performance test with lof cfm vacuum vs high cfm vacuum.

Post# 369537 , Reply# 24   3/30/2017 at 05:47 (389 days old) by sebo4me (Cardiff)        

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So it is possible to manufacture a bagless cleaner that still has decent airflow. Still a loss in CFM but respectable.

Post# 369545 , Reply# 25   3/30/2017 at 08:39 (389 days old) by crazykirbydude (Lexington, KY)        

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The Electolux Model 30!!! It pulls more than my Dyson, and you can run it until the bag is PACKED! The best part is, they are pretty much indestructible. You can get one on EBay for something in the range of $40. I really love mine!

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Post# 369592 , Reply# 26   3/30/2017 at 16:46 (389 days old) by wyaple (Pickerington, OH)        

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What is the power usage of your Electrolux UltraFlex? 85 CFM through the cyclones is probably a record! My Dyson DC14 can only do 77 CFM (measured through the hose), but that's using 1296 Watts (brush roll spinning on carpet).


Post# 369596 , Reply# 27   3/30/2017 at 18:36 (389 days old) by Mike811 (Finland)        

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Well now it uses 2100w motor. Original motor was only 700w (EU regulation model). It felt too underpowered. So when I got a bad vacuum for free with good motor, I swapped it. Performance increase was huge, but so was the noise level. I should have bought the original Electrolux motor It would have been much quieter and better quality + it would had same dimensions than the old 700w motor. Those +2000w vacuums were common before EU regulations.
However the end result was nice what it comes to performance.

Post# 369601 , Reply# 28   3/30/2017 at 19:44 (389 days old) by wyaple (Pickerington, OH)        
Well no wonder you have reasonable cyclone airflow then...

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Let's do an efficiency calculation, shall we?

2100 Watts / 85 CFM = 24.7 Watts per CFM for your UltraFlex
1296 Watts / 77 CFM = 16.8 Watts per CFM for my DC14

I can only imagine how poor the airflow was using only a 700 Watt motor. I'd guess something like 30-40 CFM, which would be very difficult to vacuum with. I'm still amazed that such a large motor fit. Did you have to make many modifications to get it to fit?


Post# 369619 , Reply# 29   3/31/2017 at 05:08 (388 days old) by Mike811 (Finland)        

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2100 motor is bigger in diameter and it didn't fit straight on. I had to cut some parts inside the motor compartment.
There was also problem with the motor mounts. It was very hard to get it sit right and I had to made new front gasket for it.

2100w motor what I use in it now is from the cheap vacuum. It's so called screamer motor. A bit annoying to my ears.
UltraFlex is designed to be used with the 700w motor. So all airways are designed to be efficient as possible to compensate the small motor.
US model UltraFlex has a 12amp = 1300w motor. Suction in it is 250 airwatts. 700w = they don't tell.


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