147
Valves
Micro-MeteringValves
Flow rates as low as 3.5 µL/min*
1/4-28 fat-bottom and 10-32 coned designs available
Materials of construction: PEEK
™
, PTFE
For fne control of fuid fow rates, Micro-Metering Valves can reduce
outgoing flow to as low as 3.5 µL/min*. These needle valves are
perfect for use with peristaltic pump fuid-transfer applications, mass
spectrometry, and fraction collection.
Upchurch Scientific
®
Micro-Metering Valves can also be used to
regulate gas fow in helium sparging lines and as a fow-dependent
variable back pressure regulator. For fow independent regulation of
back pressure, please see pages 152 –153.
Flow path materials are PEEK polymer and PTFE. All versions of this
valve have 0.020” (0.50 mm) thru-holes.
*At 1.0 mL/min incoming fow rate with room temperature water
P-445
1/4-28 threaded
PEEK Micro-Metering Valve
0.73”
(1.85 cm)
1.28”
(3.25 cm)
Thumbscrew
0.49”
(1.24 cm)
OUT
IN
Part No. Material OD Tubing Thru-hole
Internal
Volume
*
Includes
Micro-Metering Valves
P-445 PEEK, Black 1/16”
0.020” (0.50 mm) 7.7 µL
(2) XP-230
P-446 PEEK, Black 1/16”
0.020” (0.50 mm) 7.2 µL
(2) F-120
P-447 PEEK, Black 1/8”
0.020” (0.50 mm) 7.7 µL
(2) XP-330
*
Maximum internal volume, with valve fully open
Micro-Metering Valves
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Back Pressure Considerations
The Micro-Splitter Valves are designed to work when both effuent fow path
pressures are nearly identical. However, the split fow path will often have
higher back pressure than the waste fow path, making it hard to achieve
any split fow at all. There are two possible solutions. Place a back pressure
regulator (see pages 152–153) on the waste fow path that is equal to or
slightly greater than the pressure on the split fow path. Or, switch the two
effuent pathways such that the split fow pathway is attached to the “waste”
port on the valve and the waste fow pathway is attached to the “split”
port on the valve. (Please Note: This second method may result in a loss of
adjustment sensitivity.)
Prime/Purge Valve
Air within the pump head can cause noisy pump operation and fow
instability. Solve this problem by placing a High Pressure Micro-Splitter Valve
(page 146) inline between the pump and the injector valve. You can then
safely divert pump fow to a waste container at a suffcient rate to dislodge
the air. Remove air from the solvent line leading to the pump with a Low
Pressure Prime/Purge Valve (page 155).
Multi-Column and Detector Systems
Does your work require analyses with multiple columns and detectors that use
the same mobile phase? If so, install one of our High Pressure Micro-Splitter
Valves after your injector. A single injection can then be split to two separate
columns and detector systems, at two different fow rates. This economical
set-up eliminates the need for an additional pump and injector valve, while
allowing data to be obtained simultaneously.
Post-Detector Interfacing
Use a Medium Pressure Micro-Splitter Valve to route fuid exiting an initial
detector to other devices, such as a mass spectrometer and a fraction
collector. The valve will split and reduce the fow rate to that required for MS
interfacing, while diverting the remainder of the fow to the collector (a back
pressure regulator may also be required for this set up, available on pages
152 – 153).
Other Applications
These valves are also suited for other applications, such as adapting a
standard HPLC system to handle microbore analyses. For more information
and plumbing diagrams for this application and those listed above, please
contact your local distributor or IDEX Health & Science directly.
Application Note
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