SF Sizes

[Chad Speier]

I find it unacceptable that my 356cfm plate only flows 347 on the bench. I can't live with that.

I need to know why and I think I found it. It was calibrated wrong due to the wrong delta used therefore that makes the calibration wrong!

I honestly feel benches should read the same if they are calibrated properly.

[Brucepts]

My thoughts on the calibration; They simply measure the total flow on each range using their calibration plates or a standard they use on all benches. The max cfm the bench flows on each range is the scale length. I feel there is no calibration for scale linearity, can't be as it's a fixed rise manometer!

You can't change the angle of the rise to calibrate it properly for scale linearity. The calibration is simply for max flow on each range. If the orifice on that range is larger or smaller in diameter it simply makes your cfm range higher/lower and this is what you are seeing on their calibration label. You really have no clue what the actual internal orifice diameter really is. Obviously, we can see from the calibration labels that the orifice plate diameters are different as the benches are all built the same and the water gages are the same so the only variable is the orifice diameter.

Plugging this info into a Flowcom simply allows you to now see this difference digitally as it simply matches the water gages. You can't plug in an orifice diameter or change the Cd? You simply mimic the calibration label which we can now see really isn't a calibration it's just a max cfm on that range is it not?

On the PTS DM you can change the calibration factor (which effects scale linearity), orifice plate diameter and Cd (discharge coefficient) so the DM can be calibrated across a scales range just not it's max cfm range. The calibration factor is tested/set in my shop and should not need changing in the field as it's tested against a water gage and cross checked against each channel. The orifice plate diameter is set based on the plate's actual dimensions, the Cd is set based on calibration orifice testing.

So it's all very interesting . . . can a DIY flowbench really be as good as the "Industry Standard"???

[Chad Speier]

Or I should have just done what Darin told me to do. My 356 plates flows that on my PTS and on his bench at both RM and when he was at Pro-Filer. Told me to take the manometer reading to come up with the NEW calibration factor and use a black shapie to fix the SF calibrations on the bench!

Sounds logical!

[1960FL]

First off a Happy Thanksgiving to all of you in the states.

Rick, no need to get all worked up.

I am not worked up I am Pissed, as the PTS product and other Quality DIY Benches are being negated because they are not "Professionally Built". The fact of the matter is they are being focused on because they do work and work very well, lets just say good enough to make the Big Name Guys look a little sloppy. Then when a guy with a quality built PTS bench starts kicking the ass of the guy with the $$$$$$$$$ SF bench he cries to his SF rep and all the forum nation FOUL!. KMA

I have the ultimate solution and i will implement it, I have found the standards "Orifice Plate Construction and Mastering Specification" and I am going to invest in an AMSE Nozzle that will flow in a range of 50 to 300 CFM based on depression I will then implement the software required to calibrate based on the Nozzle. I will work with Bruce to implement a recordation, logging and labeling process. Then PTS will have an ASME NIST traceable standard thus PTS plates and benches will be able to be validated. To reach 100% of the standard Bruce will need to find a local anodizer for those that want to meet the hard surface requirement of the standard.

This industry needs to move to a valid standard and that my friends is not BIG BLUE! and some Hokie check plate, it is math and science. Then maybe they will get called on the carpet.

Ahhh, thats normal. But a smart SOB.

Thanks Chris but not really, at least not as smart as those in the "Society of Head Porters"

Rick

[65mustang393]

The SF version of the PAP, the expensive $800 ones. They essentially do the same thing as the the PAP, correct? I'm guessing the SF employee who comes up with the chart takes a plate, flows it, see's what the difference is between what the plate is supposed to flow and then factors that into the chart.

How would that be any different than taking a PAP and modifying the SF bench to match the PAP? I don't see a problem with that.

My question is why the PAP and the SF plates don't agree. I sent my PAP to a SF600 in North Carolina and it's pretty much the same as the SF300 here in VA. I will see what the SF600FC reads later today (after I deep fry a bird).

Let's say SF's cal is wrong. Do you try to fix every SF bench out there or maybe have two sets of cal numbers for yourself? One that's "real" and one that's "SF fake".

If you're a little low it's ok. If you're a little high, you get crucified!
Gerald

[1960FL]

Gerald,

How Porters manage their catalog of data is important, but those in the know have a standard that they check to and the worksheet should always reference that standard and it should not be what is supplied with the bench it is one you keep for life.

I was going to buy these plates from SF yesterday and when speaking with the sales department (wanted to have a rep come visit my shop) they wanted the serial number of my machine etc. etc. and Why i wanted them? Why?! OH and they could not answer the question of Do they come with the NIST Traceable Certificate???
Uhgg then I started thinking if i buy these plates with no Cert i am just comparing myself against them and not working toward an industry standard I would rather compare myself to this list of companies like GE, Lockeed, Pratt & Whitney, NASA that use the nozzles i have found rather than then Big Blue.

The problem Gerald is Big Blue has become the pseudo standard in which some use and we have seen that no two are alike even of the same model, not a good standard! If you strive to be honest in your calibration you will never be wrong and that requires an empirical reference. As Derrin told chad claibrate to what is real and remark your bench, then make sure you have the knowledge and tools to defend your position.

And that is why i will do what i said above.

Rick

[65mustang393]

First off a Happy Thanksgiving to all of you in the states.

Rick, no need to get all worked up.

I am not worked up I am Pissed, as the PTS product and other Quality DIY Benches are being negated because they are not "Professionally Built". The fact of the matter is they are being focused on because they do work and work very well, lets just say good enough to make the Big Name Guys look a little sloppy. Then when a guy with a quality built PTS bench starts kicking the ass of the guy with the $$$$$$$$$ SF bench he cries to his SF rep and all the forum nation FOUL!. KMA

I have the ultimate solution and i will implement it, I have found the standards "Orifice Plate Construction and Mastering Specification" and I am going to invest in an AMSE Nozzle that will flow in a range of 50 to 300 CFM based on depression I will then implement the software required to calibrate based on the Nozzle. I will work with Bruce to implement a recordation, logging and labeling process. Then PTS will have an ASME NIST traceable standard thus PTS plates and benches will be able to be validated. To reach 100% of the standard Bruce will need to find a local anodizer for those that want to meet the hard surface requirement of the standard.

This industry needs to move to a valid standard and that my friends is not BIG BLUE! and some Hokie check plate, it is math and science. Then maybe they will get called on the carpet.

Ahhh, thats normal. But a smart SOB.

Thanks Chris but not really, at least not as smart as those in the "Society of Head Porters"

Rick

The SF's seem to repeat well with each other. Six SF benches below and on the intake they were from 94.6% to 98.4% of whoever the standard was.

The home made benches did well too. IMO, Eric Weingartener's work get some instant credibility because his PTS bench showed 98.5% on the intake and 96.1% on the exhaust. No one is going to cry that his numbers are inflated.

If you're going to sell heads, you should have your stuff flowed on a couple other benches. It'll just save you some headaches.

[Brucepts]

I'm thinking . . . price increase on PTS products after this discussion!!!! lol

Currently, in the process of building a PTS Flowbench store to allow easier ordering of my products.

Sorry for taking this off track . . . . did send off 2 emails this AM to local anodizing companies (keeping post on topic)

[65mustang393]

Did you see the serial number on my bench? It was 6981 and that was from early 1999! If the SF benches are all jacked up (which they probably are), how do we fix the 12-15 thousand that are around the world?

Like Stalin said "Quantity has a qaulity all its own".

I'm not saying it can't be done... it's just going to be a long uphill battle because you're going to have thousands of SF owners crying that the homebuilt bench reads higher because it's homebuilt, not because it's accurate.

[65mustang393]

Bruce, you are more than fair in your prices. You should have the j-pitot market locked down tight, with those prices.

SF is stupid high on new stuff. The only way to afford their bench is used and when the economy is down or someone is desperate for cash. Under those circumstances you can find an SF600 Flowcom for $4000-6500. Someone I know paid over $14K for the same bench new. That's just stupid.