Waters 1500-Series, Operator'S Manual

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Overview of the 1500-series HPLC pumps 1-5
gases are then carried away by the vacuum pump. The following figure is a
simplified schematic diagram of the vacuum chamber.
Vacuum chamber schematic
The longer the eluent is exposed to the vacuum, the more dissolved gases are
removed. Two factors affect the amount of time the eluent is exposed to the
vacuum:
• Flow rate – A lower flow rate increases the amount of time the eluent is
exposed to the vacuum. “Degassing efficiency” on page 1-4 , addresses the
effect of different flow rates on the concentration of remaining gas.
• Surface area of degassing membrane – The length of the degassing
membrane is fixed in each vacuum chamber.
Overview of the 1500-series HPLC pumps
The 1500-series HPLC pumps combine the most important aspects of eluent
delivery for HPLC: high precision, reliability, and smooth eluent flow. All
pumps perform their intended functions equally well:
• The 1515 isocratic HPLC pump is designed for precise isocratic
analyses, with flow rates up to 10 mL/minute.
• The 1525 binary HPLC pump achieves reproducible, binary gradient
delivery, with exceptionally smooth concurrent-stream blending with
flow rates of up to 10 mL/minute.
Degassed
eluent out
Gas out
(to vacuum pump)
Vacuum chamber Eluent channel
More gas
in solution
Less gas
in solution
Gas-saturated
eluent In