Bio-Rad BioLogic Signal Import Module (SIM) - Manual (Page 39)

2.6 VALVES
BioRad offers an extensive variety of valves that enable greater flexibility for multiple sample and advanced
application options. The DuoFlow system controls 3 AVR high pressure valves and 3 SV low pressure
valves. DuoFlow systems with a Maximizer double the number of valves to 6 AVR high pressure and 6 SV
low pressure valves. Methods that include automated injection, buffer selection, column switching, and large
volume fraction collection are easily performed using various valve configurations.
For further discussion of valving applications and protocols, refer to Chapters 8-9.
2.6.1 AVR7-3 Sample Inject Valve
The AVR7-3 sample inject valve is a 7-port, 3-position valve for injecting samples and is an essential
component of all DuoFlow systems. It is rated to 3500 psi (233 bar) and is designed with non-metallic
wetted parts and minimal internal dead volume. Some features of this valve include:
• Patented make-before-break design (MBB TM ) prevents pressure spikes when the valve rotates from
one port to another, eliminating baseline interferences and prevents pump shutdowns due to
transient over pressure situations. This is especially beneficial when using more fragile low pressure
columns or flow sensitive detectors (e.g. refractive index).
• Applications include sample injection, reverse flow chromatography and two-column switching.
• A valve rebuild kit is available.
Figure 2-10. AVR7-3 Sample Inject Valve
Auto Selection Valve
A
COLUMN
GRADIENT
PUMP
SAMPLE
LOOP 3
4
5
SAMPLE
LOOP
SAMPLE
INJECT
WASTE
WASTE
6
7
1
2 3
4
5
DESCRIPTION OF BIOLOGIC DUOFLOW SYSTEM SYSTEM OVERVIEW
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