How to estimate the flow meter DP for pump sizing? 4

[nli2]

When pump sizing, there could be many different type of flow meters, vortex, orifice, coriolis, magnetic etc.
Question is how process system engineer estimate the flow meter reasonalbe pressure drop ?

Thanks for the help in advance.

nli

 

[pleckner]

Talk to a vendor or your instrument engineer. You can also get this information from many vendor cataloges and/or websites.

 

[SeanB]

You are right - it will depend on the type of meter. But when making an allowance for pressure drop in a pump calculation I usually assume 2 - 3 psi.

 

[djack77494]

Pretty standard differential pressure transmitter ranges are 0-50, 0-100, and 0-200 inches of water column. 200 inches is roughly 7.23 psi. Practically, you'll probably want to have about half the dP of the transmitter at design flowrate, and often about half of the induced pressure drop is recovered downstream of the orifice. I concur with Sean's answer - allow for 2-3 psi.

 

[CJKruger]

nli2, for most new orifice installations I assume a 100 inH2O dP range, which translate to roughly 1-2 psi permanent pressure drop.

 

[nli2]

thank for the all valuable response!

nli

 

[danw2]

I've used some inexpensive paddle wheel flowmeters on water with fairly signficant DPs (about 9-10psi in a 1" line), but the device's spec sheet clearly provided a pressure loss table.

Magmeters are line size with negligible DP loss.

Pitot tubes create less DP than an orifice plate, but with a resulting lower useable DP range.

I don't have a sizing program, but when DP loss has been an issue, I've asked the vendor to run the calculation and tell me what the calculate 'permanent pressure loss' value is. They always do.

 

[GL431]

For pump sizing allow 200 mbar permanent pressure drop for an orifice flow meter. That is about 2-3psi as mentioned above. They actually come in at 60-120 mbar permanent pressure drop.