More airflow tests.

[tekjunkie28]

LFM and CFM don't correlate unless you are measuring LFM for a given size.
LFM is speed given over time while CFM in a volume over given time but I'm sure you now that I would like to know more about how you came up with this conversion factor. Also extremely important here is the aK number or "free space" air has to flow at the entrance of the power head.

PS I have yet to find a vacuum with as much suck power as my shop vac with a hepa and drywall dust bags.

 

[blackheart]

In truth

The process was developed by Bill, Wyaple on here. I have no idea how he came up with the conversion. I just go with it. I wanted to see what sort of numbers my machines were pulling and the baird meter isn't exactly an effective tool for comparison since it's on a scale of 10 it leaves you thinking there's a dramatic difference between the numbers. I just learned about his process and started to do it myself with a few differences. It's been an interesting process for me some of my machines do better than i expect but most of them actually do worse than i had hoped.

and for those paying attention to the thread I'll have 4 more machines done, hopefully tonight the measurements have been taken, now it's just a matter of conversion, and photo editing.

 

[blackheart]

Simplicity S10P

Pretty impressive from a 9 lb upright. With it's nylon bristles it also has excellent agitation.

 

[blackheart]

Sebo X4

As thought the Felix is indeed more powerful.

 

[blackheart]

MIele turbine

I didn't bother taking the full tests as i was more focused on the turbine aspect for Harley besides both Mieles have the 1200 watt vortex

 

[blackheart]

Miele C3 cat and dog.

Despite having the same motor the hose losses and wand losses are quite different i'd assume it's due to the wiring in the hose and the electric channel which consumes wand space.

 

[tseg]

Thanks for the Miele Turbo vs. Powered head comparisons. I have a C3 Alize suction only, for which I added a turbo head months back. On some of my medium dense pile Persian rugs the turbo is tough to push, but I guess I could open the vent to reduce suction yet keep the beater bar up to speed... but I intuit that may degrade performance further relative to deep cleaning.

With the above said, I just dropped a bit over $500 today to get a powered cord/wand/head combo (SES236) so I will now have a fairly complete powered and unpowered Miele system. Based on your comparison above and comments about the wired tubing/hose constricting air flow will I be feeling positive with the results of my pricey addition? I'm thinking your turbo head comparison testing may not be completely accurate in reality because when bristles are restricted by the carpet, flow my be further restricted as the turbine creates more resistance but should not have the same result with a powered head. Could this be a correct assumption?

 

[blackheart]

Your assumption

Should be correct. As the brush is put to carpet it will slow the turbine which should impede it's airflow further. So really the figure is more like a max flow figure, in use it'll be less. Though i cannot tell you how much. An electric tool is going to give you better agitation and despite overall losing more through the electric hose and wand you still do have more airflow at the base. Though distributed over a larger opening.

 

[wyaple]

GM8901 Conversion Factor

This is how you convert feet per minute into CFM when using this anemometer.

Diameter of GM8901 Anemometer Detector = 2.1875 inches
Radius = 1.09375 inches = .0911458 feet
Detector Area = 3.1415926 x .0911458 x .0911458 = 0.0260990 (rounded)

Sooooo, if the vacuum generates 5000 ft./min that would be:
5000 x .026099 = 130.5 CFM

Hope this helps,

Bill

 

[wyaple]

Miele C3 Cat & Dog

Devin,

When you first gave me the measurements of the C3, you had measured 101 CFM at the end of the hose and 95 CFM at the end of the extended wand (just before going into the power nozzle). Do you have any idea as to why your newer measurements are so much lower? The end of wand readings are off by 14 CFM, which is huge. And a drop from 79" to 18" of water lift at the PN probably means there's a major leak somewhere.

Bill

Initial Measurements:
Hose: 101 CFM
Wand: 95 CFM

Second Measurements:
Hose: 95 CFM
Wand: 81 CFM

 

[wyaple]

Baird Meter Conversion Table

Although I've posted this many times before, here it is again. From Baird "0" to Baird "8", the spring in the meter itself is fairly linear and amazingly accurate. The last two markings, namely "9" and "10", are non-linear as the spring becomes stretched beyond its linear limits and the graph flattens out somewhat.

The spring follows Hooke's law, that is F = -kX

Bill

 

[blackheart]

I cannot be completely sure but here's my thoughts on the difference. A new bag was put into the machine to ensure the highest possible flow.

We had used a baird meter before to measure it's flow. The meter i used was the shop's, i have no idea how old these meters are but seeing as the place has a long history with kirby i'd guess they are pretty well used which could perhaps cause the spring to stretch out a little bit and lose some of it's pull.

While this should not be a factor it's not the same wand we measured from the first time. A customer needed a wand replaced and her machine was under warranty. She uses two of them for house cleaning and needed a wand pretty quickly so we figured we'd take the wand from the higher machine which was probably not going to move anytime soon. We then just ordered a new wand and put it with it. I can't recall whether or not we fully extended the wand the last time, this time was wand was fully extended.

As for the waterlift differences when taking the wand measurement i noticed an audible leak coming from these little things. With the nozzle difference an attempt to create a seal on the box causes a lot of leakage just like with most nozzles a lot of it comes from the neck of it. I also can feel a small amount of air being drawn from where the 2 halves of the nozzle's housing join together.

when doing these tests I measured hose and wand cfms first with both canisters since i tape my baird adaptor to the vane to ensure there's less loss so i know the orientation of the meter was not an issue. Wattages were close at 1149 and 1158 so the speed setting was not a factor either.

I had actually performed the C3 nozzle test twice. After taking it's initial measurements I started to take pictures and I couldn't help but think that there's no way those numbers could be right and I must have done something wrong. SO i re-tested it and got the same numbers.

I did want higher numbers from this machine. I feel like it's a really nice vacuum and, I guess, I just had higher hopes for it.

 

[tseg]

I suppose some other ways to slice and dice the testing is to swap turbo head with powered head on C3 and run tests... And do similar swap with complete non-powered hose setup just to ensure the power source is identical (understanding the 2 different units have the same motor). Why? To better control and measure the variables.

 

[drsnuggle]

Miele U1 is great!

Blackheart: I do not want to hijack this tread but I do need to respond.


 


Sorry if I sounded negative about the Miele U1. I am not. I completely agree with you. The quality is outstanding, the brush is powerful and it is versatile (I can fit my Miele Twister to the wand and use it as I would with a canister).

 

[blackheart]

An annoying process

I've been trying to re-measure my Simplicity S40P and I'm still not matching my original set of numbers with the dirty bag. It seems like it's for some reason difficult to get the baseplate of the machine to create a good seal with the box.
My original numbers (prior to this thread where:
1 motor: 86.83 CFM
2 motors: 99.15 CFM
Then i put in a new bag and got the numbers above. I'm not exactly sure what i did wrong in that test but the numbers were signicantly lower, i feel i may have held the wrong side of the vane to the box.
1 motor: 67.8 CFM
2 motors: 83.23 CFM

So i finally ran another series of tests tonight.
1 motor: 84.77 CFM
2 motors: 95.55 CFM
Bag door open (direct air motor only): 98.63 CFM.

Something is still off here a machine with a dirty bag should not have more flow than a machine with a clean one. I'm much more satisfied with these numbers though. I feel the Synergy are the best cleaning uprights you can buy. So I'd love to see their maximum airflow. I know a new synergy can pull a wooden dowel away from a new Kirby avalir but there's not too huge of a difference the kirby can snatch it away if the synergy is being pulled backwards. Multiple adjustments were tried same result.

 

[tolivac]

I am wondering for these airflow tests if a Wood box,or even metal one can be built for these tests-with adjustable gaskets for sealing the nozzle,tool to the box.The tests are interesting,though.Vac builders should take note!

 

[882]

blackheart C2 measurements...

Does anyone have any guess why the C2 measurements look (generally) so much better than those of the C3... I would think that the smaller bag of the C2 would potentially cause a lower CFM recording -- but it appears that something else along the line has not only compensated for that but aided the C2 performance.

Any idea what is happening there? -- Those C2 number look almost identical to the numbers that wyaple measured/posted on a C3 in April.

 

[tseg]

C2 v C3... just guessing C2 shorter hose and non-electric hose/wand and different nozzle could all impact the results.

 

[blackheart]

I have some ideas.

Wyaple's cfm measurements were based off baird meter readings that I took. The baird meter used has likely been used for many Kirby demos leading me to believe that the spring in it may be stretched out a little which would lead to higher readings.

The measurements I took were measured with an anemometer I got a wind speed and thanks to Bill (wyaple) that can be converted to volume.

Now as to the Differences in flow. The motors are the same. the differences are in the hose and wand. The C3's hose has an electric cord running through it. Not only does that take up space in the hose but it could potentially create turbulence. The wand is also narrower thanks to the electric components being in the way.

 

[882]

It is still very interesting just how close the your (blackheart) C2 readings are to the ones you shared with Bill for the C3 earlier.

What is especially intriguing to me (and still feels a bit of an enigma) is not just how close the measurements are between those two data sets but the crazy drop previously noted from the end of the hose on the C3 to the end of the wand (not present on the C2 sample). IF the wiring is the airflow death source -- it seems like its effect should be felt through the hose as well as the wand. It seems like something really was going on with the wands on that C3.?. Note that the airflow differences between the C2 & C3 were not all that different at the end of the hose (Tseg's shorter hose take could account for that slight difference perhaps). Seems like there maybe more to the mystery. Love that there is a place to see this all and discuss.

It's all very fascinating.