ImprovedCollector Electrode Installation
onSRI GCs November 2010
BeginningDecember 2010 all SRI FID
detectors are equippedwith an improved
collector electrode. Detectorsmanufac-
tured after December 2010 have a “stop”
machined into the detector body to posi-
tively locate the collector relative to the
FID jet. The new collector needs to be
manually positioned in earlier detector
bodieswithout the “stop”.
The photo at right shows theFIDdetec-
tor body next to the new style collector
and old style collector.
The new style collector electrode ( 8670-
0154 ) is insulatedwith a ceramic tube,
whereas the old style is insulatedwith a
vespel ( polyimide ) ferrule. The vespel
ferrule could become soft or deteriorate
at high temperatures.
The superior high temperature
ceramic insulator used on the new style
exhibits less noise and drift especially
when the detector body is very hot
( >300C ). While both collector elec-
trode styles incorporate a vespel ferrule,
the new style does not rely on the vespel
ferrule to provide electrical insulation,
instead the insulation comes from the
alumina ceramic.
To position the collector in theFID body,
remove the cap from the detector.
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Old style
FID body
New style
New
Old
The new vespel ferrule is
different than the old style
