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Restriction Orifice Thickness Calculation/Formula and source Standard

Restriction Orifice Thickness Calculation/Formula and source Standard

Restriction Orifice Thickness Calculation/Formula and source Standard

(OP)
Hi, I want to know the formula to calculate Restriction Orifice Thickness, I found on the internet this one "Minimum RO thickness ≥ SQRT [(0,681-0,651*Beta)*deltaP/Y] * pipeID" it says it is according to R.W. Miller, but I could not find it in the Flow Measurement Handbook Miller 3rd Edition.
Can anybody help me with this matter? Which is the formula and the source (book and chapter or a Standard)?
Thanks.

RE: Restriction Orifice Thickness Calculation/Formula and source Standard

Wrong Miller..... (a very common name, BTW)

This Miller refers to the calculation methodologies of Roark as contained in his timeless "Formulas for Stress and Strain"

http://rwmillerengr.com/fcfiles/FAQ.htm

(Miller, of course is selling his own software)

http://www.madinstro.net/tech/opthick.html

Many of the postings on the net refer to something called "ASME 3-31-3 Calculation orifice thickness"

This specific topic has been discussed before on these hallowed fora:



MJCronin
Sr. Process Engineer

RE: Restriction Orifice Thickness Calculation/Formula and source Standard

(OP)
Thank you very much, MJCronin. I have no access to that ASME 3-31-3. And the link you put with those formulae does not have a source either.

I hope I can find or somebody answers this issue clearly.

RE: Restriction Orifice Thickness Calculation/Formula and source Standard

Turik,

You've already received a quite straightforward answer from MJCronin, which seems anyway to elude you.

From plates theory: σmax = 6Mmax/t^2

where:
σmax =max stress
Mmax = max bending moment
t = plate thickness

Moreover σmax ≤ Y
where:
Y = yield strength of the material the plate is made off

From "Roark’s Formulas for Stress and Strain" sec. 11-14 you can find the formula to compute Mmax
Then work out for t (definitely boring) and the game is done.

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