3 replies to this topic

[saiedmehdipour]

Hi Dear All;

I need to know the location of FT regarding of CV in process line,
I know it is better to install FT in upstream of CV it's that because if cavitation or fleshing accure
through control valve do not effect in measuring of FT, but in some P&ID i sow FT located in downstream of CV, i need to know the reasone.

if anybody can help me kindly please tell me standard, refrence book, or any referable document
and send me to srmehdipour@yahoo.ca.

Best Wishes

[fallah]

Hi Dear All;

I need to know the location of FT regarding of CV in process line,
I know it is better to install FT in upstream of CV it's that because if cavitation or fleshing accure
through control valve do not effect in measuring of FT, but in some P&ID i sow FT located in downstream of CV, i need to know the reasone.

if anybody can help me kindly please tell me standard, refrence book, or any referable document
and send me to srmehdipour@yahoo.ca.

Best Wishes

Generally,FIT installation location would be better upstream of relevant FCV (as you mentioned),especially in liquid containing lines to avoid two phase flow happening.

In cases there is no concern about the shortage of space,flashing/two phase flow.... (gas containing lines),feed back/feed forward control may dictate the location of FIT.

[djack77494]

I can think of no process reasons for locating the FT downstream of the control valve and several reasons, including those mentioned by you and fallah, to locate the FT upstream, as is commonly done. However, there may be non-process reasons such as layout issues that make the downstream configuration more desirable. As long as the process and measurement quality issues are properly addressed, it is not necessarily a problem to go with the downstream configuration. Measurements using an orifice and many other flow meters are more accurately accomplished in fully developed flow. About the worst location from a flow development point of view is downstream of a partially open modulating valve; i.e. the control valve.

[Qalander (Chem)]

Normal Level IQ of mine suggests that

FT should always be upstream;

or wherever the flow is fully developed and pipeline is completely filled to ensure 'sensing of the system'