User manual

10 1260 Nanoflow Pump User Manual
1 Introduction to the 1260 Infinity Nanoflow Pump
Introduction to the Pump
Hydraulic Path Overview
The NanoFlow Pump is based on the 1200 Series Binary Pump (pressure limit
400 bar, active inlet valves), and performs all the functions necessary for a
µ-flow solvent delivery system. Basically, these functions are:
• Low pressure metering and high pressure delivery
• Solvent compressibility compensation
• Variable stroke volume
• Column flow measurement and control
Low pressure solvent metering and high pressure solvent delivery are
accomplished by two pump channels, each capable of delivering a maximum of
2.5 mL/min flow at up to 400 bar pressure.
Each channel consists of an identical, independently controlled pump unit.
Each pump unit includes a metering drive assembly and pump head assembly.
The pumphead assemblies both consist of two identical chambers, pistons and
seals, plus an active inlet valve and an outlet valve.
The channel flow outputs are initially joined by a low volume pre-mixer, and
are then connected by a capillary coil to a pressure pulse damper. The
pressure pulse damper also serves as a pressure transducer, which sends
system pressure information to the user interface.
The mixer output flow, called main flow, is connected to the Electronic Flow
Control (EFC) system. The EFC system consists of an Electro-Magnetic
Proportioning Valve (EMPV) in series with a flow sensor. The EMPV is
protected from particles in the mobile phase by a solvent filter frit.
Responding to user-entered column flow setpoint, the EFC system determines
how much of the main flow volume is ultimately delivered to the column. The
remaining main flow volume, which is not required by the column, is diverted
to waste by the EMPV.
Under user control, the EMPV can also function as a purge valve, for purposes
of solvent changeover, etc. In this case, the EMPV is totally open, and the total
main flow is diverted to waste.