Thermo Scientific Vanquish VH-P10-A-02, Руководство по эксплуатации

Страница: 211 / 238

8 • Troubleshooting
Vanquish Pumps (VH-P10-A-02) Operating Manual Page 211
8.5.2 Resolving Pressure Pulsation or Shifts In Retention Time
When
You observe pressure pulsation or shifts in retention time.
Chromeleon 7.2.6 and later
Run the Advanced Leak Test (see section 8.3, page 207 ).
Chromeleon 6.8 and Chromeleon 7 earlier than Chromeleon 7.2.6
Check the compression values.
The compression values of the pump heads can provide valuable
information for troubleshooting.
Follow these steps
1. In Chromeleon, check the
Compression
values for the pump heads
(compression on the left side in the pump head = CompressionDrv1 ,
compression on the right side in the pump head =
CompressionDrv2 ).
The values indicate the compression of the last stroke in percent.
The compression value should be less than 100%.
♦
With isocratic conditions, the compression value should remain
stable.
♦ When running a gradient, the compression value changes
roughly proportional to the pressure curve.
If the value is close to 100%, the required precompression may not
be reached and pulsation may occur.
The table shows guide values for some solvents (pure solvent,
degassed) with the pump being purged and the pressure being
stable for some time. The values are linear to the pressure.
Pressure (MPa) Compression in % with
Water Methanol Acetonitrile
25 11% ± 7% 22% ± 7% 22%± 7%
50 21%± 7% 41%± 7% 38%± 7%
75 30%± 7% 57%± 7% 53%± 7%
100 39%± 7% 71%± 7% 66%± 7%
125 47%± 7% 82%± 7% 76%± 7%
150 55%± 7% 90%± 7% 85%± 7%