User manual

76 1260 Nanoflow Pump User Manual

5 Optimizing Performance

How to Optimize the Compressibility Compensation Setting

The compressibility compensation default settings are 50 × 10

-6

/bar (best for

most aqueous solutions) for pump head A and 115 × 10

-6

/bar (to suit organic

solvents) for pump head B. The settings represent average values for aqueous

solvents (A side) and organic solvents (B side). Therefore it is always

recommended to use the aqueous solvent on the A side of the pump and the

organic solvent on the B side. Under normal conditions the default settings

reduce the pressure pulsation to values below 1 % of system pressure which is

sufficient for most applications. If the compressibility values for the solvents

used differ from the default settings, it is recommended to change the

compressibility values accordingly. Compressibility settings can be optimized

by using the values for various solvents described in Table 19 on page 77. If

the solvent in use is not listed in the compressibility table, when using

premixed solvents and if the default settings are not sufficient for your

application the following procedure can be used to optimize the

compressibility settings:

1 Start channel A of the pump with the adequate flow rate. The system

pressure must be between 50 and 250 bar

2 Before starting the optimization procedure, the flow must be stable. Use

degassed solvent only. Check the tightness of the system with the pressure

test.

3 Your pump must be connected to a data system or Instant Pilot with which

the pressure and %-ripple can be monitored, otherwhise connect a signal

cable between the pressure output of the pump and a recording device (for

example, 339X integrator) and set parameters.

Zero 50 %

Att 2^3 Chart

Speed 10 cm/min

4 Start the recording device with the plot mode.

NOTE

Use the 1260 Nanoflow Pump in the Normal Mode at least 100 µL/min.