Relief system piping 1

[ASA20]

I have space constrain on a relief platform which has a lenght of 6000mm,i want to carry out piping layout of the relief system which has an 8" 900#RJ ristriction orifice which is placed inbetween a 10" ball valve and an 8" ball valve.I have to considered the straight run reqiurement of 7930mm upstream and 1270mm downstream of the risriction orifice.What do you recommend

 

[dbaird]

Look into using straightening vanes. Straightening vanes are installed in the upstream section of meter tubes to reduce flow turbolence. Installed upstream of flow meter when adequate upstream pipe run section can not be met their use often allows sufficient reduction of stream meter tube lenght.

http://www.emersonprocess.com/DANIE...sheets/Straightening Vanes Cat 1100 363KB.pdf

David Baird
mrbaird@hotmail.com
Sr Controls Designer
EET degree.
Journeyman Electrician.

 

[TD2K]

I'm confused what you are asking about regarding an orifice, upstream and downstream distances and a post titled "Relief System Piping"

 

[ASA20]

TD2K,
The ristriction orifice is a flow measuring instrument installed on the process line and my job notes stipulates a pipe striaght run before and after the orifice should have a distance of 7930mm and 1270mm.This arrangement is part of a relief system ,that was why i posted it with that title.
Hope this will help to clerify the quetion.

 

[robsalv]

It seems like you're describing installing an RO in the relief path / flare system.

It's just not done - especially if you're describing an 8" plate with a much smaller orifice in it.

Do I have it wrong?

 

[PAN]

adeboy,
The straight run length should depend on the beta ratio of your orifice.

If you really require the more run length, you should arrange the piping.

 

[jahall333]

adeboy,
I assume you mean Orifice Plate Meter when you refer to the RO? If so are you metering gas? If so is it indicative or is it fiscal metering?
Maybe I'm barking up the wrong tree but if it is fiscal gas metering you should look in your project nominated standards, if it mentions ISO 5167 then there are tables for minimum lengths of straight pipe based on factors such as the number of bends in the pipe prior to the meter run, and the orientation of the bends. Using a flow conditioner, either a tube bundle as mentioned by David Baird, or a flow conditioning plate, will allow you to reduce straight lengths.
Check your design/project standards to see what you need to comply to.
Justin.