jfholm wrote:Now if I understand it correctly you are trying to check the 3.5" orifice on top of the bench at 28" correct? The 3.059" one is inside and that one gets it's value from the Delta P of 13.4" H2O.
I was just thinking that if I had a larger hole on top of the bench and put the manometer at 28" whatever it pulled through the 3.059 hole would be the true factor for that hole.
However, if the 13.4 is the true delta, what should the factor be? Not 442.2??
Chad Speier wrote:Yes I had the FP in manometer mode.
If they are indeed calibrating at 13" then the 442.2 is not correct?? And if it should be 449.5 instead of 442.2 then my 356 plate at 78.2% would really be 352 cfm.
correct??
Yes, What I would like to do some time is put a head on my bench and check the Delta P at 25%, 50%, 75% and 100% manometer reading and check the Delta P at each reading. If you are testing at 28" that will be the reading above the orifice and the reading below the orifice on the vacuum source side of the orifice should be 41.4" H2O if you are getting a 13.4" H2O delta P. I would think that would stay steady.
The value of your internal orifice stays the same in relationship to your delta P
I have been going off of the program Ed put on the forum to help calculate the flow through an orifice. I will attach it so you do not have to hunt for it. Thanks Ed! Great program. It uses Microsoft excel
John
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I know you are probably getting tired of my off the wall posts but I am trying to understand what SF’s intentions were in there design so we have a logical path to follow to a comparative calibration.
First off the Intended (Design) Delta P is most likely 13.37 not 13.4 yes splitting hairs but it equated to .5 CFM. To my earlier point I do not believe anyone makes a 7.015” rise manometer, thus we know you measured it at around 13.4. So the SG of the oil used is 1.91 the rise of the incline must be 7” and thus DP = 7” * 1.91 or 13.37” based on the SF documentation #5 range is 0 to 450 cfm by using the spreadsheet with air density standards a Preasure of 13.37 and orifice ID of 3.059 then to get to 450.0 the CD they designed around will be .6014.
Am I understanding your posts correctly? But again I am not sure where you are getting the 442.2 /442.9 Number you are using in your flow calc? it is my understanding that #5 on the SF 600 is 0 to 450CFM.
