Thread Number: 34065  /  Tag: 50s/60s/70s Vacuum Cleaners
Flour UNDER the Carpet Test For Hoover U4007
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Post# 369191   3/25/2017 at 16:40 (452 days old) by wyaple (Pickerington, OH)        

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I bought a new 5'x7' Mohawk medium pile carpet for vacuum tests in my basement recently. I wanted to see what vacuums had enough power to pull flour up through the carpet into the dust bag.

The test was completed with only 2 complete strokes (2 forward/2 backward) at medium speed right through the middle of the flour. I think this qualifies as maybe 95%-99% total pickup?

This Hoover Convertible U4007 was quite the winner with 107 CFM at the nozzle and an airflow density of about 4.6 CFM per square inch. AND all this cleaning power comes from a motor only requiring 4.1 Amps @ 120 Volts = 492 Watts.

Enjoy! Oh, and I will be publishing more of these tests as time permits.


  Photos...       <              >      Photo 1 of 4         View Full Size

Post# 369214 , Reply# 1   3/25/2017 at 19:38 (452 days old) by Paul (MN)        


I appreciate your attention to detail with your testing. I also like your well-designed graphs and charts. Good information and easy to reference-thanks.

I used to have the Convertible model U4317, which had a full hood like yours. Its weaker suction made me conclude that it wasn't very effective, but your tests reveal otherwise. I would guess, anyway, that a newer model made from c.1982-85 would have had some upgrades to improve its performance. Even if it were the same as yours, 107 CFM is impressive!

Your U4007 has a groovy appeal with its goldtone hood, too. In case you haven't seen it already, here's a Vacuumland thread that contains a full-color brochure of it (scroll to replies 8 & 9):

Post# 369391 , Reply# 2   3/28/2017 at 09:39 (449 days old) by kirbyvertibles (Independence, KS)        

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Never underestimate the vacuum with low power!!! I remember at last years convention in the cleaning competition there were 2 power vacuums (I forget now what they were) and someone asked if they could use my little 1971 RCA Whirlpool 2,000 stick vac looking vacuum. I said sure but that's kind of unfair to the poor little Whirlpool. Everyone thought awe the poor little guy......... Well I'll be damned if I didn't bring home a first place ribbon as it beat the others.

Post# 369665 , Reply# 3   3/31/2017 at 14:04 (446 days old) by Warren_L (Georgia, USA)        
This is relevant to my interests...

As a mechanical engineer, I am very interested in testing procedures.

Can you tell me what flow meter and fixture you used to find the CFM of your vacuum?

I would like to find a reliable and repeatable way to test the seal leakage in my tank vacuums.
Nilfisk's have a motor gasket that you need 5 hands to fit properly. Even then it's a guess.

Do you use a specific amp-meter? I've used Fluke meters extensively and find them very accurate.

I too would like to post some results, but I have no idea of the standard methodology used.

Post# 369667 , Reply# 4   3/31/2017 at 14:38 (446 days old) by dysonman1 (undisclosed)        
Tacony Manufacturing

dysonman1's profile picture
Tests brand new vacuums (the ones they make as well as competitors) using a very scientific method.

A mechanical arm to "push" the vacuums is used, so the human variable is eliminated.

A brand new piece of test carpet is cut to fit a platform with a standard pad attached.

A standard mixture of test dirt (looks like sand and talc to me) is measured, weighed, and applied to the carpet, then a heavy roller is used to 'grind' it in.

The carpet containing the 'dirt' is weighed.

The carpet is laid on top of the pad, and the vacuum being tested goes to work for a standard number of test 'strokes' (8 I believe).

The carpet is then reweighed - the difference is the percentage of dirt 'picked up'.

The testing lab is also used for two other tests - durability (life of the motor) and carpet wear tests. Vacuums run constantly, with the mechanical arm pushing the machine, until the motors die. The number of minutes (hours) is calculated to determine motor life. Carpets are also weighed at the beginning and end of the life tests - any loss of carpet nap is determined by weighing, as well as an observation test to see (by a human) any negative effects to the carpet.

Years ago, the old VCCC went to the Kirby Company. We were in the testing labs, and the engineers gave us a piece of test carpet, which the old VCCC used for the cleaning contests. I've had nothing to do with the VCCC for more than a decade, so I have no idea if the same carpet is being used today for their tests. However, at the time, the Kirby Company told us that ALL manufacturers use the same brand and type of carpet for their wear and cleaning tests.

Post# 369676 , Reply# 5   3/31/2017 at 15:46 (446 days old) by wyaple (Pickerington, OH)        

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It doesn't take much to perform tests on these machines. Even if my measurements are off by a whopping 1%, you and I know that's not very statistically significant.

For "quick and dirty" airflow tests, use a Baird meter (right now Tom G. is cringing). My airflow chart for it is posted here so you'll know what an "8" actually means.

For my precision tests, grab yourself a GM8901 anemometer for about $25 from eBay. Get a more expensive meter if you desire, but this cheapie can register airflow up to 260 CFM (10,000 ft/min) in repeatable increments of less than 0.5 CFM (about 20 ft/min).

If all you desire to test is small airflow drops from a hose, the Baird meter will reliably tell you when about 3-4 CFM is lost by reading about one-half a number lower (at least in the zero to 8 range). I would imagine that a 3-4 CFM loss is probably good enough resolution for most people.

Of course being an Engineer, follow the exact same initial conditions when testing. Hose stretched out the same way, same line voltage, and bag and/or cyclone cleanliness, etc.

For measuring line voltage and/or current, nothing fancy is necessary either. I have a single piece of bench gear that originally costs well over $2000 and can read out to 8 digits of accuracy. A complete waste as a $13 power consumption meter is plenty fine.

If you want an airflow box, you'll have to build your own, but they are easy to construct. I made mine essentially for free out of cardboard (sealed it of course) and can reliably measure from about 2 CFM to 150 CFM from nozzle heads, which is good enough for now I suppose.

Feel free to email me for more info...


CLICK HERE TO GO TO wyaple's LINK on eBay

Post# 369915 , Reply# 6   4/3/2017 at 15:27 (443 days old) by Warren_L (Georgia, USA)        

How did you arrive at the data points of the Baird Meter?
What calibration tool did you use?

Post# 369927 , Reply# 7   4/3/2017 at 20:09 (443 days old) by wyaple (Pickerington, OH)        

wyaple's profile picture
Please take a closer look at my previous post. I used a GM8901 anemometer to pin down the mysterious Baird meter readings.


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