1 Getting started with the Alliance e2695 Separations Module
30 July 29, 2013, 715003794 Rev. B
low-internal-volume degasser chambers. The result is shortened instrument
priming and equilibration times, and minimum delay when resuming
operation from an idle state or following a solvent change.
The degasser’s vacuum pump is designed specially for membrane degassing of
HPLC mobile phases. The continuously running pump provides rapid vacuum
pull-down at high speed and consistent vacuum level at low speed.
Degasser considerations
Degassing efficiency is based on the solvent gas load and the length of time
that the solvent remains in its vacuum chamber. Gas removal efficiency
decreases as the solvent flow rate increases because the solvent is in the
vacuum chamber for less time. Adopting a normal analytical flow rate range of
0.000 to 5.000 mL/min, the degasser removes most of the dissolved gasses.
Because you can perform dry and wet priming at flow rates greater than 5.000
mL/min, you must expose the solvents to the degasser vacuum for a short time
(after priming) at zero flow rate (see “Equilibrate solvents in the in-line
vacuum degasser” on page 130).
Vacuum degasser pressure transducers
Separations modules are equipped with an absolute pressure transducer
(APT), which is unaffected by altitude or barometric changes. The following
table lists the attributes of APT-equipped separations modules.
Absolute pressure transducer attributes:
Item Absolute pressure transducer
Units displayed kPa, bar, psa
Sign of displayed unit Positive
Theoretical maximum vacuum
(based on 1 atm at sea level)
0 psia
Operating range (using the
default vacuum pressure
threshold)
22.1 to 0 kPa (0.2 to 0 bar, 3.2 to 0 psia)
(If pressure is out of range, an asterisk
(*) appears in the pressure field.)
“Typical” value 5.0 to 10.0 kPa (0.05 to 0.10 bar, 0.7 to
1.5 psia)
More vacuum Smaller number is displayed
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