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[james.corrobro@gmail.com]

hi, 

 

i got to look at some P&ID for orifice type flow meter (attached similar). I see that they use pressure  measurement upstream of flow meter and a temperature measurement downstream of flow meter for density correction for gases. 

 

Since there will be some pr. drop across orifice and some temp, drop across orifice (due to J-T process). Should we not measure pressure and temp. upstream and downstream. Please help on this,

Attached Files

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[breizh]

Hi ,

They should be able to get access to the pressure (calculated) [ Pabsolute - Delta P orifice]  combined with the temperature to deliver a density (calculated) .

 

Take a look at the set up from Spirax Sarco , quite similar .

 

Definitely Pressure and temperature must have the same reference (upstream or downstream the orifice).

 

hope this clears your doubt.

 

Breizh

Edited by breizh, 27 January 2019 - 12:01 AM.