flow straighteners 4

[Yobbo]

Dear reader,

My question concerns the application of flow conditioners. I know they are applied in combination with flow meters, that need a certain straight pipe length upstream and downstream. The purpose is to reduce these lengths. My question is whether there have been developments to optimize the effectivity of the unfiformizng effect of the flow straightener, while maintaining an as low as possible residual pressure drop. I did try to scan the internet, but I couldn't find any clue. Could you provide me some leads?

Thanking you in advance for your effort I remain,

With best regards,

Karel Postulart, The Netherlands
Nuon Power Generation

 

[pmover]

Check / Investigate AGA Report No. 3 is my suggestion or investigate w/in the AGA website.

Good luck.
-pmover

 

[zdas04]

I have not installed an orifice meter since 1998 without a flow conditioner. Many of my clients don't agree with that and leave them out. Then I go back to do a material balance and find that too many of the new tubes can't be reconciled with off-system delivery numbers.

Square-edged orifice measurement calculations assumes that the flow is "fully developed" which means that the flow approximates a 1/9 th power flow profile (which results in 90% of the mass flow in the middle 80% of the flow area with now asymmetry). We pretended to get that for decades with an "AGA tube bundle". Dr. Elizabeth Laws did some extensive research to show that the AGA Tube Bundle added zero value and by itself did nothing to force a specific flow profile.

The first flow conditioner was the Mitsubishi plate (1973) that was expensive and couldn't be verified to work. The next Flow Conditioner was based on the work of Dr. Laws and the first commercial product (the Laws Plate) came on the market in 1992. It was still expensive and still difficult to verify that it worked. Jim Gallagher came out with a two piece conditioner (now sold by Savant) in the early 1990's that was considerably less expensive and had quite a bit of quality data. The state of the art today seems to be the Canadian Pipeline Association Flow 50E Conditioner. It has a good database of successful examples and a really good price.

AGA 3 Appendix 2D has a well-defined protocol for certifying that a new device will meet the standard. Any flow conditioner that has satisfied that protocol will provide excellent results. Any flow conditioner without that certification should be considered junk.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[ElSid1]

Assumption of GAS for previous responses. Is that correct? There are also straightners for liquids which I have used for inlets to pumps and meters

 

[zdas04]

Absolutely. I would never pay for something like the CPA 50E for a liquid measurement application (there are less expensive options for liquids).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[ElSid1]

Never used the CPA50E. I have used the cheng flow straightners (

http://chengfluid.com)

and Metraflex uses a similar design (probably pays a royalty). The cheng had better characteristics (lower losses, quicker straightning) than other systems I've used.

 

[hacksaw]

regardless of where you use the 50E I learned something, thats worth something, flow metering is not for the faint of heart in the real world...

 

[zdas04]

It my not be for the faint of heart, but it seems to be done by a fair number of Bozo's. My wall of shame of pictures of gross screw up's is actually a 7 MB folder of low rez photographs. Pretty much everything that can be done wrong regularly is done wrong.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.