Nozzle CFM Tests

[wyaple]

I finally built an airflow box. Well, probably not quite what you would expect as it is made of cardboard and sealed with packing tape. But for CFM tests, it works perfectly! In the near future, I will build another one but next time out of wood, sealed with glue so it can withstand suction tests without collapsing. I tested with and without bags or filters and with and without the brush roll on if possible.

Comments:
As you can see, the Kirby Sentria II blows away (sucks away?) the competition, while the more expensive Rainbow pales in comparison. My trusty 36-year-old Electrolux (with a new vinyl hose) holds its own against most others along with my resident cheapie, the sub $100 bagged Hoover Tempo Widepath. Of note is the 90’s designed Riccar 8850 easily besting the much newer Simplicity. The Simplicity has three 1” wide air-relief holes in the top of the rug plate that appear to keep the metal brush roll clean but drastically lower the nozzle CFM. Enjoy!

Bill

 

[wyaple]

Airflow Box Pics

The first two are of the airflow box and the third depicts the Simplicity's air-relief holes.

Bill

 

[sptyks]

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<li>Hi Bill, it would be interesting to see the difference in airflow, if any, between the Sentra II and Avalir.</li>
</ol>
 

 

[cam2s]

Interesting results

I'm not surprised to see the Sentria aced this test, it is a very powerful machine. The rainbow was a bit of a surprise though. I have a Rainbow D3C...it feels like it has more power than that (of course totally subjective) Even if that is really all the air it moves I feel confident that it cleans my carpet just fine. I'm also surprised that your Riccar didn't post higher numbers. When I run mine of an empty bag it roars with all the air moving through it. Again totally subjective but I would put the performance of my 8000 series Riccar on par with any of my Kirbys.

Of course it's also important to note that the Airflow and Waterlift work together, you will have to combine some of your data and make a chart with both numbers in.

 

[wyaple]

Stan, The Sentria II and Avalir

Should be the same machine mechanically speaking. I forget exactly when Kirby "upped" the power a bit. I think it was sometime during the Sentria I series, but someone that knows exactly when that happened please post the correct info.

Anyway, you can certainly see a difference between the G4, G5 and G6 versus the Sentria II. A nice bump in CFM. It appears that Kirby accomplished this by allowing the motor to spin at a higher RPM, thus using a bit more power. My current measurements for those machines while vacuuming medium pile carpet are:

G4: 6.53 Amps
G5: 6.85 Amps
G6: 6.63 Amps
Sentria II: 7.46 Amps

Bill

 

[wyaple]

Cameron

If you notice a big difference in your Riccar's airflow when removing the bag, you may want to switch to cloth HEPA bags. I use them in all my machines (including my 1980 Lux Olympia One) and they maintain airflow much better than any paper bag ever made, especially when nearing full capacity.

And the reason I post numbers is to avoid as many subjective opinions as possible. My G6 does about 120 CFM at the nozzle versus my 8850's 71 CFM. Not even close (of course both machines are performing like new).

Something else to consider is rug plate pressure. The G6 maxed out my gauge (beyond 10 lbs.), while the 8850 pulled a reasonable 2.875 lbs. Kirbys are supposed to create a seal with the carpet while the Riccar rides on top of it.

Make no mistake though, I love using my Riccar and recently acquired Simplicity Symmetry. They are very pleasant to listen to compared to the newer Kirbys.

As far as water lift goes, here's a link to my updated list.

http://www.vacuumland.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?31771_8

 

[suckolux]

Bill my Diamond shows 7 amps

 

[cam2s]

I always do use the cloth HEPA bags in my machines whenever possible. In my experience those Riccars make a nice throaty roar with a fresh bag...maybe its just me who knows lol. Many of the machines listed are all great cleaners, even if they don't post incredible raw numbers. Good design goes beyond having a lot of horsepower so to speak.

 

[wyaple]

David

Those ratings are only approximations of a motor doing a certain task (i.e. idling, etc.) and also vary based on manufacturing tolerances.

Here's a current usage chart of all my machines. See how the current varies based on the workload? Possibly all Kirby's rated at 7 Amps might actually pull that much on high pile carpet but on medium pile, it's a no-go except for the Sentria II.

Bill

 

[sptyks]

Bill, I think Kirby increased the power a bit on the late Sentria I machines by redesigning the mini emptor to increase airflow. As far as I know, the Motor has remained unchanged throughout  the entire G series with the possible exception of the 2 speed Diamond edition. Do you agree with this? I would like to know if you have evidence to the contrary.

 

[wyaple]

Stan,

Maybe a combination of reduced exhaust back pressure and slightly higher RPM give the newer Sentrias/Avalirs a slight bump then? I currently don't have a very good method for measuring electric motor RPM, but I can hear a pitch difference when both machines are running. The Sentria II definitely runs at a higher pitch. I ran a sound analyzer app on my phone to confirm the difference.

Also, there is an age difference to consider here as well. Should a 20 year old machine with old bearings and commutator really run as well as a 4 year old one?

Anyway, I'm rather ecstatic that my airflow box worked as well as it did and I was able to post these results.

Bill