SSI America BINARY SOLVENT DELIVERY MODULE 90-2581 REV B - Manual (Page 5)

Flow adjustment in 0.01 ml increments, from 0.01 to 10.00
ml/min with a precision of 0.2% RSD (10mL/min heads)
• Microprocessor advanced control
• Digital stepper motor design to prevent flow rate drift
over time and temperature
• Back panel RS232 serial communications port for
complete control and status monitoring
• Remote analog inputs (e.g. voltage) to control flow rate
1.1.2 Wetted Pump Materials
Pump heads, check valve bodies, and tubing are made out Stainless
Steel or PEEK™. Other materials are synthetic ruby and sapphire
(check valve internals and piston).
1.1.3 Self-Flushing Pump Head
Self-flushing pump heads provide continuous washing of the piston
surface without the inconvenience of a manual flush or gravity feed
arrangement. The self-flushing pump head uses a diaphragm and
secondary set of check valves to create a continuous and positive flow
in the area behind the high pressure pump seal. The flushing solution
washes away any buffer salts that have precipitated onto the piston.
If not removed, these precipitates can abrade the high pressure seal
and cause premature seal failure, leakage, and can possibly damage the
pump.
MOBILE
PHASE
SAPPHIRE
PISTON
SECONDARY
SELF-FLUSH SEAL
PRIMARY
HIGH-PRESSURE SEAL
FLOW OF
FLUSH SOLUTION
PISTON
MOVEMENT
Figure 1-1. Self-Flushing Pump Head
1-3