1
Introduction
Hardware Components
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Accela 600 and 1250 Pump Hardware Manual
Thermo Scientific
Figure 2.
Front panel of the Accela 1250 Pump showing the latest proportioning valves
These topics describe the main components of the LC pump:
•
•
Liquid Displacement Assembly (LDA)
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•
Vacuum Degasser Assembly
The 600 and 1250 pumps contain a built-in vacuum membrane degasser that removes
dissolved gasses from the mobile phase. Dissolved gasses can cause many problems in HPLC
and must be kept to an absolute minimum for best performance. The solvent degassing
system consists of four independent channels that are maintained at a constant vacuum of
approximately 50 mm Hg absolute. Each channel has a volume of less than 500 μL, which
provides superior degassing efficiency capable of limiting dissolved oxygen to a level of
only 2 ppm. By varying its speed, the vacuum pump maintains a constant vacuum level. This
eliminates the excess baseline noise and drift caused by vacuum pump cycling.
Vacuum degasser
assembly
Liquid displacement
assembly
(Optional) seal wash pump or
cover plate
Static
mixer
Purge valve
(Optional) dynamic mixer or
placeholder module
Proportioning valves
(latest version)
