DETECTORS
Flame Photometric Detector - FPD
Switching Between Sulfur and Phophorus Modes
1. TurnOFF theGCpower.
2. Unplug theBNCcableconnecting thePMT to theamplifier.
Disconnect thesecondaryhydrogenandbothairsupply linesat
theirbulkheadfittingson theGCdeck.
3. Remove theheaterblockcoverbyunscrewing thephilips
headscrewon topof it. Slide thecoverupandoff theblock,
andcarefullyremovethewhiteinsulation.
4. Loosenthe1/8”SwagelokfittingthatsecurestheFPDdetector
assemblyon theheaterblockenough togently rotate theFPD
assemblyabout45
o
towardthefront
of theGC (see the
Front View
and
SideView
illustrations to theright).
5. Stabilize theFPDassemblywhileyou loosen the1/4”Swagelok fitting that
secures thePMThousing to theFPDdetectorbody. Slide thePMThousingout
of thedetectorbody. Ifyou’reswitchingPMThousingassemblies,setaside the
PMThousingyou just removedandskip tostepnumber7. Ifyou’reswitching
filters,proceed to thenextstep.
6. Unscrew thePMThousingstainlesssteel
retainingnut, thenset it (with thePMTand its
socket)aside. Thebandpass filter isscrewed
into the toppartof thePMThousingagainsta
blacko-ring,andhas2depressions in itsframe. Itcanbeunscrewedusing
openneedle-nosedpliersbutyoumustbeverycarefulnot todamageor
scratch thefilter. FPDsensitivitywillbereduced if thefilter is improperly
installedordirty.
6. Inspect theblacko-ringforanynicksorcutsandreplace it ifnecessary. Place thealternatefilter,with its
coloredsidefacingdown toward thePMT, into the toppartof thePMThousingagainst theblacko-ringand
tighten it. Remember, itmustbe light-tightandgas-tight. Replaceand tighten thestainlesssteelretainingnut
with thePMT in itssocket.
7. Slide the topof thePMThousingcontaining thealternatefilter into theFPDdetectorbody,and tighten the
1/4”fitting thatsecures it inplace.
8. Gentlyrotate theFPDassemblyback to itsoriginalangle,and tighten(withawrench) the1/8”fitting that
secures it to the heater block. Reconnect the gas supply lines and theBNC cable. See the note on the
followingpageregardingproperjetpositioning.
ThebandpassfilterspecifiedwhentheinstrumentwasorderedcomesinstalledintheFPDdetectorassembly.
Thereare twooptions for switchingbetween sulfur andphophorusmodes. Youcanpurchaseeither an
additionalfilteroranadditionalPMThousingandswitchthemasnecessary. Phosphoruswavelengthfiltersare
availableunderSRIpartnumber8670-0083;sulfurfiltersareavailableunderSRIpartnumber8670-0082. A
PMThousingwithabandpassfilteroftheotheroptionalwavelengthspecificationsisavailableunderSRIpart
number8670-0084(specifysulfurorphosphorus).
Loosen
this fitting
Slide thePMT
housing out
of theFPD
body
Front view
Loosen
this fitting
GC front
Sideview
+45
o
-
Filter inside PMT
housing assembly
Use these
depressions
for filter removal
