Let's measure some CFM and separate

[Bob Foster]

The wheat from the chaff
The talkers from the walkers
The facts from the fantasies
The bullshit from the buckwheat

Which TMs manufacturers at Connections will tell me I can't hook this up? I'll be sure to tell you which ones don't and their excuse.

Who want's to accompany me as a witness and give me a hand?

I will bring the fittings to hook on to any thing from 1.5" to 3" and will try it at 50 and 100 feet.

Should take about an hour or so to do. The truth shall set you free...... !gotcha!

 

[ruff]

Bob,
Have you considered getting a life?

What the heck................
Long live science.

And God bless, Bob.

 

[FB7777]

I think that would be better to do at a smaller fest and let the vendors "opt in"


I don't think it would prove sheet tho, as many truckmounts can be modified with larger vac plumbing and 2.5 hoses to achieve better results for relatively short money


I'm quite happy spending a couple hundred bucks to improve my vac performance on our Butlers with 2.5 hoses but I bet the stock Butler machine at a trade show would not score as well as other machines

Reliability and resale value are more important to me than a CFM number off the showroom floor

 

[Bob Foster]

Fred the point is that some of us believe that some of these manufactures are bull shiting us about their specs. This has nothing to do with hose performance and everything to do with machine performance.

 

[Mike Draper]

mine will be there, do all the testing you want on it.

 

[Bob Foster]

Your machine is the first one I would like to test.

 

[FB7777]

I know fully what this is about and in the spirit of full disclosure would you tell the manufacturers what your motives were?

Its to discredit their CFM numbers or bash them for not letting you hook up

Which TMs manufacturers at Connections will tell me I can't hook this up? I'll be sure to tell you which ones don't and their excuse.

You're performing this 'experiment' on behalf of Judson and yourself , and clearly all the vendors are damned if they do and damned if they don't

 

[Jim Martin]

Fred the point is that some of us believe that some of these manufactures are bull shiting us about their specs. This has nothing to do with hose performance and everything to do with machine performance.

they are just numbers that get rattled off to try to impress everyone......its performance out in the field under different conditions is where it is going to shine....or fail.......

 

[FB7777]

eggszactly Jim

what numbnuts buys a 20K machine due to CFM number?


Each blower has a rating don't they?


I don't have a clue what Butler claims their max cfm is

 

[Dolly Llama]

Bob, does that go in-line on the vac hose??

If so, I'd love to see how the numbers change when a wand is stuck on the end of the hose.
and then placed on a carpet

don't all the CFM numbers go right out the window when the choke point is the wand slot??
(even before it touches the floor)

can't the math guys calculate how much air can be pulled thru X amount of sq inches @ 15hg??
I'll throw some numbers out, maybe one youinz that pay attention in fizzics class can calculate it for me.

lets say the wand slot has 1.8 sq in of opening
(that's an actual measurement from the slot glide on our Ti)
the "empty space" on the glide measures .150" x 12" = 1.8 sq in

so how much air can possibly be moved thru that much space @ 15 hg??

class?..anybody???


..l.T.A.

 

[ruff]

I pretty much agree with Fred.

If previous Bobby posts are any indication.......
Chances are that the Judson Juggernaut will be in the "Praise the Lord" category.
As with 'Slop and Gurgle' and multiple others.

Praise the Lord.

Ask Merty if you have any questions.

 

[ruff]

Bob, does that go in-line on the vac hose??

If so, I'd love to see how the numbers change when a wand is stuck on the end of the hose.
and then placed on a carpet

don't all the CFM numbers go right out the window when the choke point is the wand slot??
(even before it touches the floor)

can't the math guys calculate how much air can be pulled thru X amount of sq inches @ 15hg??
I'll throw some numbers out, maybe one youinz that pay attention in fizzics class can calculate it for me.

lets say the wand slot has 1.8 sq in of opening
(that's an actual measurement from the slot glide on our Ti)
the "empty space" on the glide measures .150" x 12" = 1.8 sq in

so how much air can possibly be moved thru that much space @ 15 hg??

class?..anybody???


..l.T.A.

For heavens sake Larry,
Shish!

If it rips the damn tufts out of both primary and secondary backing...that's too much suction.

If it takes three days to dry.........not enough suction.

Everything else is pretty much the same.

Give or take a few

 

[Bob Foster]

Yes Larry it goes in-line and all I have to do is put different adapters on it to bush it down to the appropriate size. It would be wrong to bush it up.

Larry these are great ideas and suggestions but I got to tell you that after sitting down to dinner and thinking about this I think I'm better to leave the test equipment at home. The way I brought this forward probably defeated my own efforts to use it there anyway.

Its highly likely that obstacles will be put in my way if I geeked out at Connections with this instrument so fuggit. Like Fred suggested it might be better to be used in a different venue. I have other uses for this instrument on a project I'm working on for my new truck build.

I'm going to Connections to to see my buddies, see some toys, gossip and generally have a good time. By the way, normally this is a very expensive meter to buy and its accuracy is unquestionable. How you use it is important and I have a few bench marks in mind for testing.

My personal opinion is that some TM manufacturers are trumpeting the blower manufacturers specifications that in reality don't represent the actual performance of the TM that the particular blower is installed in.

Want to bet that those that whine about the methodology of testing will be the ones that have the most "questionable" specifications.

 

[Dolly Llama]

Foe heavens sake Larry,
Shish!

If it rips the damn tufts out of both primary and secondary backing...that's too much suction.

If it takes three days to dry.........not enough suction.

Everything else is pretty much the same.

Give or take a few

that;s kind of what I'm getting at, Ofer
Do blower CFM numbers mean anything if only so much air can possibly be pulled thru the wand slot??


come on, wheres the rocket scientists at??


how much air can possibly be pulled thro 1.6 sq in @ 15hg??


class?
anyone? anyone?


9]http://www.youtube.com/watch?v=dxPVyieptwA9]
..L.T.A.

 

[dgardner]

Bob,

I'm not familiar with the Hedland flowmeters, so I looked yours up. It is intended for compressed air service. Dead giveaways are the 0-200 psi gauge attached and the 40-130 inlet pressure marks across the top of the cfm scale. According to the manufacturer's data sheet, at 400 cfm your meter will have a pressure drop of 5.49 psi, 11.2" Hg or 152" water column. Fine for compressed air at 100 psi, but very bad for vacuum flow if you're trying not to skew the numbers. Hooking it inline with a wand would be meaningless, as it is probably as great or greater a restriction than the wand itself. Here is the data sheet:

http://www.hedland.com/resources/products/Page35-36-Air-Gas_Meters_2-09.pdf

 

[Bjorn]

"hey can I test your truck mount " ehhhhh?

are you thinking of buying something????

" well no but I need to report back to the brain trust on MB board "

MB board SATANS DEN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

" yes MB "

I don't think so

 

[Dolly Llama]

Yes Larry it goes in-line and all I have to do is put different adapters on it to bush it down to the appropriate size. It would be wrong to bush it up.

Larry these are great ideas and suggestions but I got to tell you that after sitting down to dinner and thinking about this I think I'm better to leave the test equipment at home. The way I brought this forward probably defeated my own efforts to use it there anyway.

Its highly likely that obstacles will be put in my way if I geeked out at Connections with this instrument so fuggit. Like Fred suggested it might be better to be used in a different venue. I have other uses for this instrument on a project I'm working on for my new truck build.

I'm going to Connections to to see my buddies, see some toys, gossip and generally have a good time. By the way, normally this is a very expensive meter to buy and its accuracy is unquestionable. How you use it is important and I have a few bench marks in mind for testing.

My personal opinion is that some TM manufacturers are trumpeting the blower manufacturers specifications that in reality don't represent the actual performance of the TM that the particular blower is installed in.

Want to bet that those that whine about the methodology of testing will be the ones that have the most "questionable" specifications.

Bob, read my lips;

it don't fckin matter

cause I'm betting it's physically impossible to pull more than a couple hundred CFM thru a 1.8 sq in space

naw'mean??


someone must have a slide rule big enough to figger it out, right??

..l.T.A.

 

[Bob Foster]

Your right Larry and while people get all caught up on CFM their vacuum relief is open and their not taking advantage or have the capacity to use more are

unless,


they are using larger tools and hoses or longer runs.

That's why lots of guys that thought they need a 59 blower in reality don't if their unit is engineered properly.

I did my research as well. I disagree with the remarks about the meter as those specs depend on what inlet and outlet sizes are used.

 

[dgardner]

I disagree with the remarks about the meter as those specs depend on what inlet and outlet sizes are used.

There are only two meters with a 40-400 cfm scale, the H870-400 and the H890-400, both have the same pressure drop. Unless you don't believe the mfgr's own chart.

What pressure drop do you believe your meter will have, and what is the basis for your conclusion?

 

[Dolly Llama]

I did my research as well.

well, sheeeit, professor , then lets make it real simple ..
1ft of 3" straight pipe with a cap that has 1.8 sq in of opening .
uncorked/unrestricted exhaust side

What's the max CFM that can be pulled thru it @15 HG??


..L.T.A.

 

[Bjorn]

I would say it would be rude to want to test something you have no intention to buy

 

[Bob Foster]

Guys I'm just trying to help and further our understanding. What I hate is people that are blowing smoke up our asses. I'm going back to the drawing board on this meter. If I'm wrong and it does look like I did fook up at least I have the guts to admit it.

 

[Dolly Llama]

Guys I'm just trying to help and further our understanding. .

me too, Brother, I promise


you want to separate the wheat from the chaff.
I want to by pass all that and get some practical meAt on the baked "bread"

naw'mean?


..l.T.A.

 

[dgardner]

someone must have a slide rule big enough to figger it out, right??

..l.T.A.

Larry, I actually had a very nice (expensive) K&E slide rule that I used (no, really) in school back in the 70's. I was going to sell it on ebay, they are now collectors items, but the stupid thing has disappeared. Rats.

Anyway, a very general calculation (that is somewhat dependant on the opening, whether rounded or sharp edges) is:

cfm = 14.5 X P X D X 2

Where P is absolute pressure difference, and D is diameter (1.8 square" = 1.514" diameter). At 15" Hg (can you really get that much vac at the wand head with a reasonable run of hose?) the absolute pressure difference would be 7.36 psi.

cfm = 14.5 X 7.36 X 1.514 X 2 = 323 cfm

The actual flow will be anywhere from 97% of this (313 cfm) for well rounded edges to 65% (209 cfm) for square edges (like a drilled hole). The formula is more accurate for pressures above 15 psi, but this is not too far off.

 

[Bob Foster]

Larry in my own way that's what needs to happen - plain speak without the hype. Once you get past the glitter and glam and claims some of these machines really aren't as great as some people think they are.

The tools (at least the right F'n ones :roll: :roll: ) and specs are just a way of us rather than them telling us what works well.

 

[Dolly Llama]

someone must have a slide rule big enough to figger it out, right??

..l.T.A.

Larry, I actually had a very nice (expensive) K&E slide rule that I used (no, really) in school back in the 70's. I was going to sell it on ebay, they are now collectors items, but the stupid thing has disappeared. Rats.

Anyway, a very general calculation (that is somewhat dependant on the opening, whether rounded or sharp edges) is:

cfm = 14.5 X P X D X 2

Where P is absolute pressure difference, and D is diameter (1.8 square" = 0.757" diameter). At 15" Hg (can you really get that much vac at the wand head with a reasonable run of hose?) the absolute pressure difference would be 7.36 psi.

cfm = 14.5 X 7.36 X 0.757 X 2 = 161 cfm

The formula is more accurate for pressures above 15 psi, but this is not too far off.

excellent!!
I didn't do too well math and "slide rules" I really knew from skool was this;
"don't stand in front of it, or Little Johnny will knock your ass over when he slides down it"

never the less, this was the part i needed;

"161 cfm"

..L.T.A.

 

[dgardner]

Larry, I screwed up, used the radius instead of the diameter. I went back and corrected the calc, and added a note. Better go back and re-read my post.

 

[Mikey P]

yeah, you better leave it at home Bob, those Galvy fittings may rust and crumble in the hour or so it takes to test all 6 truckmounts. :shock:

 

[Bob Foster]

How ironic. Galvi pipe on the ends...

 

[joe harper]

How ironic. Galvi pipe on the ends...

http://www.youtube.com/watch?v=eioyl7dI ... re=related