RO
RO
(OP)
Can anybody advise the method for calculating the thickness of Restriction Orifice?
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RE: RO
Keep in mind that is the orifice is not thin (e/d >> 0.2) then the characteristics of the RO will change.
RE: RO
Isnt RO thickness normal determined by the piping spec?
Best regards
Morten
RE: RO
Can you expand it abit more? I didn't quite understand it! "Keep in mind that is the orifice is not thin (e/d >> 0.2) then the characteristics of the RO will change."
Morten A,
Appreciate your try. What is determined by a piping engineer is the thickness of permanent blind not RO.
May I ask what country you are working in?
Cheers
RE: RO
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RE: RO
If you are taking a large drop near the top of ASME Class 600 toward ambient such as a blowdown application I would use a choke.
Plates are suitable for permanent drop but not using the standard flow element thickness. If your restriction orifice exceeds 1000 inches of water but not as significant as 1000 psi differential, my "throw-down" recommendation would be to double the thickness required by API/ISO/ASME etc. for the flow element. I would use double the standard orifice thickness as the basis for anything in flange Class 300. I would not use this basis if the plate is large and in Class 600 or higher.
RE: RO
RE: RO
RE: RO
Haven't heard that rule of thumb.
By that rule, if I have a 3/4" bore, then my plate is 3/4" thick also? Seems a bit thick.
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RE: RO
Im working in Denmark - but not as a piping engineer. My guess was just that the easiest way to make an RO would be to take a blind flange and drill a hole... Since its not for emasurement then accuracy could be less important than durability - and if the blind flange can withstand the pressure then surely the RO allso could?
But at least the poor soul got some (more) qualified bids
Best regards
Morten
RE: RO
Actually in a number of cases space is limited like the case I have run into. Ro can be made from Blind Flange but sometimes they are much more thicker. Material is SS.
Cheers mate
RE: RO
Best regards
Morten
RE: RO
For higher pressure classes the "bean" style fixed chokes are a good fit. Chokes associated with the old "oil patch" technologies are a commodity. Several patterns exist from about 1935 that are cloned by many manufacturers. The choke "beans" can be found at many supply houses throughout the world. The bean is an a venturi path within an angle body designed to accommodate any errosive wear etc. This makes for easy replacement if required.
Another method for small low pressure applications has been a union fitting with a washer plate. I do not recommend these as my industry minimizes the use of threaded fittings.
RE: RO
I would just like to contribute 2 hints to this discussion:
The first one comes from DIN-1952 paragraph 18 (“Regeln für die Duchflußmessung …”)
Thickness of an Orifice should not exceed 0.1 D; thickness of cylindrical bore should be less than 0.02 D. If overall thickness is less than 0.02 D, no bevel is required.
And the second hint comes from a TÜV approved list for minimum thickness of line blinds for pressure testing of steel pipes. Just take the first line (test pressure 7 bar(g))
Nominal flange diameter thickness [mm]
2” – 4” 6
6” 10
8” – 16” 12
18” – 24” 20
30” 25
Kind Regards,
hahor
RE: RO
RE: RO
Thanks for your replies. In my case, I have a condensate re-run pump which sends the unstabilised condensate (class 300#) to the condensate tanks (Class 150#).