4 replies to this topic

[ezralh]

Hi all good people,

 

At what condition that we put flow transmitter downstream of the control and what condition we put the flow transmitter upstream of the control valve. Thank you.

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[fallah]

ezralh,

 

System I in the attached file (flow element at upstream of the control valve) is always preferred, because in system II there is the risk of measuring error due to non smooth moving of the fluid at control valve downstream.

[breizh]

http://www.flowcontr...-considerations

 

Consider the link attached.

 

Hope this helps

 

Breizh

[SPC]

Hi everyone,

 

        System -1 is always acceptable. As Fluid moves, flow tranmitter will measure & gives signal to accurately take an action for Control Valve. Hence, reading will be correct. There will not be time lag.

 

System-2 is unacceptable. As fluid moves, to take an action control valve has to wait till signal comes from its downstream side transmitter,

 

meanwhile some more flow would have passed through control valve. Here, there will be time lag. Hence, control function would not proper  response as per desired result.

 

Your comments are highly appreciated.

 

Regards,

SPC

[kiansafaie]

in addition of mentioned comment in some condition there is risk of two phase flow in down stream of control valve and the measuring of flow in this case is more complicated. Its better to have measuring flow at upstream of control valve.
Thank you