Inlet Systems
Packed column inlet
Problems at high inlet temperatures
A common problem with conventional packed column inlets operated at high temperatures is septum bleed and the associated ghost peaks. To minimize this effect, some inlet systems are designed with steep temperature gradients throughout the entire upper length of the inlet to provide a cool septum and minimal ghost peaks. However, this temperature gradient allows condensation of high boiling point compounds resulting in nonreproducibility and discrimination against these compounds. (This effect has sometimes been mistakenly called needle fractionation.)
A thermally optimized
The septum•purgedpacked column inlet has been thermally optimized to provide an extremely uniform thermal profile throughout the flash vaporization region. This thermal profile remains very close to the inlet setpoint temperature throughout most of the gas stream. Then, up in the purge region of the inlet, a very steep temperature gradient is forced with a large cooling fin. This results in longer septum life, and reduced ghost peaking when run in a nonpurging mode.
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