Gilson PLC 2050, Руководство пользователя

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91 PLC 2050/2250/2500 PurifiCation SyStemS | uSer’S GuiDe
M
A
T
e
R
iAL
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Liquid Contact Materials
materiaL DeSCriPtion
PFA
Perfluoroalkoxy is a fluorocarbon with chemical and mechanical properties similar
to FEP. More rigid than either PTFE or FEP. FEP (fluorinated ethylene propylene)
is another member of the fluorocarbon family with similar chemical properties. It
is generally more rigid than PTFE, with somewhat increased tensile strength. It is
typically more transparent than PTFE, slightly less porous, and less permeable to
oxygen. FEP is not as subject to compressive creep at room temperature as PTFE, and
because of its slightly higher coefficient of friction is easier to retain in a compression
fitting.
PTFE
Polytetrafluoroethylene is the generic name for the class of materials such as Teflon®.
It offers superior chemical resistance but is limited in pressure and temperature
capabilities. Because it’s so easy to handle, it is often used in low pressure situations
where stainless steel might cause adsorption. PTFE tubing is relatively porous, and
compounds of low molecular weight can diffuse through the tubing wall.
Ruby / Sapphire
Synthetic rubies and sapphires are single-crystal aluminum oxides, practically pure
for the sapphire (+99,99% Al
2
O
3
). The color of the ruby is produced by adding a few
ppm (parts per million) of chromium oxide (CrO
3
). Synthetic rubies and sapphires have
a hexagonal-rhombic crystal structure, density of 3.99 g/cm³ and a water absorption
coefficient of 0%.
The principal properties of synthetic rubies and sapphires include a hardness and
high mechanical strength, excellent resistance to wear, very low friction coefficient,
chemically inert, good thermal conductivity, ideal electrical insulation.
Stainless Steel, Type 316
This chromium-nickel alloy has a low carbon and high nickel content, and contains 2
to 4% molybdenum. Its corrosion resistance is somewhat better than chromium-nickel
grades without molybdenum (such as 304), particularly in acidic environments. The
molybdenum tends to increase passivity, improves the alloy’s corrosion resistance in
general, and helps minimize pitting or pin hole corrosion under certain conditions. This
grade has good creep strength at elevated temperatures.
This is the standard tubing material for chromatography, suitable for a wide variety of
applications. It is cold drawn seamless, not welded, with close tolerances held on both
ID and OD.
Austenitic stainless steels may be used for most chromatographic applications. Type
316 is most commonly used for HPLC because of its superior chloride ion resistance.
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