Flow metering and control

[ing123]

I have a problem with controlling a small flow in a pilot plant and would appreciate any suggestion. System consists of two horizontal drums D-1 and D-3. There is 0.4 gpm flow from D-1 to D-3 under gravity. Bottom of D-1 is 500 mm above top of D-3. There is an orifice meter to measure the flow and a control valve downstream of the meter. Fluid specific gravity is 0.78. Max static head for the meter and control valve together is 350 mm (0.4 psi). What is the minimum pressure drop for the meter to measure accurately? Is the pressure drop thru the control valve sufficient to provide a meaningful control? What is the measure to judge if the control valve can provide good control? Thanks.

 

[JLSeagull]

This is a duplicate post. Consider a Coriolis flow meter or other technology instead of a head type meter for such low pressure.

 

[hacksaw]

this is not a good application for d/p meter

you get into small d/p's that are measurable but difficult to make work, the greatest concern is the limited amount of d/p for the valve to work with

there are several mass flow meters that handle these small flows. the pressure loss is minimal (usually) that will give you whats left for the valve.