GC 3-Series Midpoint – Three Capillary Columns

This GC 3-series midpoint calculator estimates the outlet column flows through columns 1, 2, and 3, the mid-point supply flow, flow ratio, and the pressure between column 2 and column 3 for three capillary columns connected in series with a mid-point pressure supply between column 1 and column 2, based on column geometry, carrier gas, temperature, and pressure conditions.

GC 3-Series Midpoint Calculator Interface

Connection Diagram

GC 3-series midpoint diagram showing three capillary columns with mid-point pressure supply between column 1 and 2

What inputs are required ?

  • Dimensions and temperature of capillary column 1, 2 and 3
  • Column 1 inlet pressure and column 3 outlet pressure
  • Mid-point pressure supply (between column 1 and 2)
  • Carrier gas

Outputs of GC 3-series Midpoint Pressure Calculator

  • Outlet flow of column 1, 2 and 3
  • Mid-point supply flow
  • Flow ratio between column 1 and column 2
  • Intermediate pressure (between column 2 and 3)

Before You Go

Want to understand how this calculator works behind the scenes?
The full article with explanation will be published soon at GC Hardware.

This calculator assumes laminar flow in capillary GC columns and ideal gas behavior at standard reference conditions. For stable mid-point pressure control, the calculated flow ratio should generally remain below 0.8.

Browse related calculators below:

If your system uses a different column connection — such as a single column, two-column series, mid-point pressure supply, splitters, or combiners — explore the other GC column flow calculators at Free GC Calculators for configuration-specific flow and pressure calculations.

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