Does hose size affect CFM performance?

[Bob Foster]

Joe Bristor of coolcuffs.net lent me his Exitech CFM meter to find out. Thanks Joe. It was eye opening.

Here are my results using my Judson TNT. Please note that the CFM readings are not complete CFMs as the way you use the meter with a flow funnel bypasses some air. The most reliant information is the percentage of loss of performance.

 

[Dolly Llama]

is that with the wand on the end of the hose?

it would be interesting to see the differences w/wand hooked up
unglided, slot, hybrid and hole to see the CFM changes


..L.T.A.

 

[Jay D]

Bob if you get a chance test it with the wand on the carpet. I always wondered how much cfm flows with the wand on the carpet. Not being sarcastic just curious. :idea:

 

[Bob Foster]

That with the vain probe on the end of a funnel on the end the hose. I think I better post some pictures of the methodology.

People will think that's all the CFM that a TNT puts out. It isn't. More pictures tomorrow.

It would be hard to do measure this from the end of the wand.

 

[Dolly Llama]

wait a minute..

i thought a stock TnT had 36 or 45(?) blower
how can you get 380cfm ATM???
Isn't that more CFM than their physically capable of ???


..L.T.A.

 

[Leslie Judson Jones]

http://www.globaltecheng.com/pdf/vacuum ... 0Curve.pdf

 

[Dolly Llama]

thanks Les

if I read that right, a 45 blower max specs (3600 rpm @15hg ) can pull 400cm?

That's with no plumbing connected, correct?


..L.T.A.

 

[handdi]

Re: Does hose size effect CFM performance?

some of u guys would work on your business as hard as u work
on this stuff
u would be rICH

 

[Bob Foster]

u]http://www.youtube.com/watch?v=uyNLW57lXBwu]

 

[floorguy]

lol Bob...

get someone to help ya...havng a little issue with filming and moving the fan thingy??

 

[Bob Foster]

Hey, it worked. shiteatinggrin

And the specs were right on to the blower specs too.

 

[Farenheit251]

Those #s correlate with what I saw in a Fluid Dynamics textbook. 3 times more airflow lost with the 2''. 150' of 2.5 will give the same as 50' of 2 inch.

From the chart it appears running 50 feet of 2.5 with 50 feet of 2" doesnt really gain that much over 100 feet of 2"
I think 100 feet of 2.5 with 12-20 feet of 2 inch is the sweet spot.

 

[Dolly Llama]

thanks Bob

good job!

I'm still curious to see what effect a wand hooked up has.
I'm suspect some CFM will be lost, but wonder if the CFM ratio differences in hoses would remain consistent
Use that large brain of yours to find a way... :wink:

maybe tape/seal the funnel onto the wand slot


..L.T.A.

 

[Bob Foster]

I think I will. I have a Mytee 14" Bently with a GreenGlide Hybrid and I have a 14" Greenhorn with all the Greehhorn Holed Slotted and Hybrid. I also have a 1.5 wand too if I can get to that one. That one I will test with and without a glide.

I'm going to test it with 50' of 2.5" with 50' of 2". I got an idea how to do it.

You know that galvanized floor register ducting...

I'll use some duct tape and seal it up real good and tape all the sheet metal seams too.

 

[Dolly Llama]

I'll use some duct tape and seal it up real good and tape all the sheet metal seams too.

I knew you wuz a McGeiver kind of guy!

..L.T.A.

 

[Jay D]

So was the cfm with the wand on the carpet. My guess would be 80-125 cfm. !gotcha!

 

[Larry Cobb]

Jay makes a good point ...

The CFM numbers will all be much lower,

with the wand on the carpet.

Larry

 

[Joe Bristor]

Larry, you still pushin Nick's Free Flow?

 

[rjs]

I just hooked up Joe's cool cuffs and a y for 4 to the door.

150 2" on the live reel = 265 cfm
150 laid out off the reel = 300
100 = 370
50 = 450

50 4 to the door 610
50 4 to the door + 50 2 in = 450
50 4 to the door + 100 2 in =350
100 4 to the door + 50 2 in =425

I think i could have done even better, i was reading the cfms at the middle of the range and not at the peak.

Give Joe at **************** a call, you can gain cfms at a low cost.

Rich

 

[Art Kelley]

I've been using 50 feet of four to the door on many jobs these past few weeks (bringing the Y to the door) and the setup and takedown is less that a minute extra time on a job compared to two inch all the way, that is with my electric reel which moves fifty feet in about twelve seconds.

 

[Joe Bristor]

Look at two of those 150' runs that Rich measured...
425 vs 265cfm.. that's a 60% improvement by simply bypassing the live reel and adding a Y!
So for the little extra effort that Mr Kelley mentions, Rich's son will be suckin 60% harder than a fellow competitor unwilling to make that same effort. Fewer dry strokes, less fuel usage, higher cleaning rates... however you measure it, that little effort is a big money maker for Rich & son.

btw, did you happen to run any tests with the stock 1.5" whip that came with your new tm?
I bet that same 150ft run would be about 225cfm, making that stock unit the most expensive portable on the market.
But at least you know how to open it up now and let that big dog breath.

Good job Rich. I hope your son appreciates you.

--------------------
Give Joe at **************** a call, you can gain cfms at a low cost.
that's a fact.

 

[Dolly Llama]

I just hooked up Joe's cool cuffs and a y for 4 to the door.

150 2" on the live reel = 265 cfm
150 laid out off the reel = 300
100 = 370
50 = 450

50 4 to the door 610
50 4 to the door + 50 2 in = 450
50 4 to the door + 100 2 in =350
100 4 to the door + 50 2 in =425

I think i could have done even better, i was reading the cfms at the middle of the range and not at the peak.

Give Joe at **************** a call, you can gain cfms at a low cost.

Rich

thanks for your effort, Rich.
I greatly appreciate guys that actually take the time to do such things

at the risk of showing my ignorance though, what size blower is needed for 600+ CFM?
and what HG is yours set at?

Thanks


..l.T.A.

 

[Shawn Forsythe]

Bob,

Too bad you didn't also have a couple of other columns in your readings spreadsheet.

1) Vacuum gauge readings (at the blower and the machine inlet orifice).
2) Simultaneous airflow measurement through the vacuum relief valve.

The hose CFM readings will vary from machine to machine, even with the same baseline. (some equipment will do better, and some will have greater percentage losses through your hose lengths/sizes)

 

[Bob Foster]

I agree Shawn. But that's why I expressed percentage for relevance.

 

[Shawn Forsythe]

My point is that not all your CFM loss is due to the restriction itself, but is significantly due to the re-direction of flow through the vac relief valve, which varies from design to design. Some units will produce a greater percentage of airflow drop through a given reduction in flow due to restriction. i.e. the percentages will vary, giving a differing relevance of drop.

How significant the vac relief is going to be will hinge on how the vac relief responds to restriction and lift rise as it approaches the set point maximum.

Also, whether the unit has "high heat clearance" lobes or not, and whether any readings were taken at a lower blower case temperature will create some interesting numbers from machine to machine. This may seem trivial, because its rarely discussed, but you would be surprised how much it means when the unit is under load.


But as in informal test, I applaud you for doing this. It is great stuff.

 

[Curtis Pennington]

http://www.globaltecheng.com/pdf/vacuum%20curves/4M%20Vac%20Curve.pdf

lol Techno Viking is da man!

 

[Numero Uno]

With my King Butler modifications,some where back in the archives section. I tested the unit for a bout 3 hours or so in the pouring rain .

Under 1450/1550/1650/1750 rpms ,at 1450 rpm's the modification was comparable to a new Butler running at Mach 2 setting. Whilst using 3/4 or so gas and hour.During each rpm set change.I refilled the gas tank returned -rehooked up hoses and re-ran unit.

It was kind of difficult at first due to the pouring rain,but Joe was with me every step of the way originally on the phone.We dialed it in perfect and HAD great results.

All with 100 feet straight(75-2.5inch/25 feet-2 inch) to wand.Was first time in what was then 30 yrs of carpet cleaning that I actualy knew what I was doing in cfm's or so...

My results were put in the Jim Cooper forum as requested,I perhaps have them some where but a tremendous amount of stuff as been tossed out now.
But good day all,omw to my job here.

Try it if you are able and see for yourselves.All I can say.While I had the unit it was one of the most interesting test device's, I ever had.

Good Day ...