2 replies to this topic

[PTSHeng]

Good afternoon,

I am currently trying to size for a client a change in transmitter range for their orifice plate as they have changed the upstream pressure.

They have provided us with and maximum and 2 other additional flow rates, and the bore size of the orifice which has been installed. 

I have realised that the differential pressure (dp) needed to obtain the same maximum flow changes when I calculate it with either 2 flow rates as normal flow.

I would like to know why this happens, and I thank everyone in advance for their input!

[TS1979]

If you got two different orifice diameters, you will need different DPs to obtain the same maximum flow change.

You can size your orifice plate with maximum flow rate and allowable DP, then your orifice plate will cover your normal operating range with lower pressure drop.

[PTSHeng]

Hi TS1979,

Thanks for your reply, but I have only one orifice bore. I would like to know why the scaled maximum differential pressure changes when I change the normal flow rates. Keep in mind the upstream conditions and flow rate will remain the same.