Flow Meter Placement
Flow Meter Placement
(OP)
When designing a flow control run in a pipe, where would be the ideal place for the flow meter? Upstream or downstream of the control valve?
Do the flow rates make a difference? What about the fluid?
In this case I am controlling the flow of steam to a reboiler that is currently on temperature control. The addition of a flow meter will allow us to switch between temperature control, flow control, or cascade temperature-flow.
Do the flow rates make a difference? What about the fluid?
In this case I am controlling the flow of steam to a reboiler that is currently on temperature control. The addition of a flow meter will allow us to switch between temperature control, flow control, or cascade temperature-flow.





RE: Flow Meter Placement
I would have the flow meter on the steam line for information (and accounting) purposes, but wouldn't control off of it. Steam is tough to get a reliable (for control purposes) flow reading. It probably won't go to zero properly, either. All of this introduces error in your control loop that can be avoided.
RE: Flow Meter Placement
RE: Flow Meter Placement
RE: Flow Meter Placement
Use the normal meter run location guidelines. Include the weep hole at bottom of plate if using an orifice plate in horizontal run. Include a condensate removal upstream of the orifice to get better metering and control.
best wishes,
sshep
RE: Flow Meter Placement
RE: Flow Meter Placement
RE: Flow Meter Placement
This is in the troubleshooting stage. We are also controlling condensate in the reboiler by putting two steam traps in parallel (instead of just one) going to a condensate pot with level control.