1260 Infinity Binary Pump User Manual 133
Test Functions and Calibration
8
Binary Pump Solvent Compressibility Calibration
Binary Pump Solvent Compressibility Calibration
Description
Each solvent or solvent mixture has unique compressibility at different
pressures. In order to deliver accurate flow with minimal pressure- and
composition ripple over the full operational pressure range, it is necessary
that the pump compensates precisely for the compressibility of the
solvents in use.
The binary pump comes with compressibility parameters for the most
common HPLC solvents and solvent mixtures. If a solvent is not available
in the list of pre- calibrated solvents, the solvent compressibility calibration
allows the appropriate compressibility data to be generated.
Technical background
The solvent compressibility calibration relies on an accurate elasticity
calibration of the pump. With a proper elasticity calibration in place, the
pump is switched into pressure control mode. A restriction capillary is
connected to the purge valve outlet. By varying the flow rate, the pump
maintains a certain pressure. The pump optimizes the compressibility
value of the solvent until the lowest possible pump ripple is reached. The
pump increases the flow rate and adjusts the pressure to the next
calibration step where the pump ripple is minimized again. This process is
repeated until solvent compressibility data for the whole operating
pressure range of the pump are available.
The compressibility data set for this solvent is stored in an XML- file in
C:\Documents and Settings\<username>\Application Data\Agilent Technologies\Agilent
Lab Advisor\2.02.0.0\data\. It can be shared with other G1312B pumps via
the controlling data system.
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