Chromatography Forum

Does anyone have a link to a simple spreadsheet tool to calculate predicted backpressure for various MP/flow rate/column packing/column dimension combinations? Thanks.
J

Not a spreadsheet, but you can download an evaluation copy of the DryLab modeling software from Rheodyne (link in the sponsors box) and use the default example. That will show you back pressure and plates when you change column dimensions, particle size, and flow.

I created a spreadhseet a while ago, it works, but the accuracy is a bit wide. Good for checking what the backpressure of a new column in a new system should be roughly.

http://www.paulhurley.co.uk/media/estim ... essure.xls

Paul.

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Paul Hurley

Paul hurleyuk

Shouldn't your formula have dc-squared instead of r-squared.

Adam

adam, I'm not sure I know what you mean. The estimate column pressure spreadsheet takes a formula from a Waters HPLC troubleshooting guide (which I've just noticed looks like it's been authoured by another member of this group, Uwe D. Neue)

The text refers to the Kozeny-Carmen equation, and relates the pressure drop across a column to the Flow Rate (F), viscosity (funny n symbol), column length (L), column radius (r) and particle diameter (dp) along with a factor (f) to account for the packing density (for silica, ~1000).

I'm not sure what dc squared can refer to.

Paul.

dc is the column diameter.

But I just rechecked the formula. You had it correct in the first place.

Adam

Thankyou for your help.