valco fittings
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ReducingUnions
Reducingunions join two tubesof
differentoutsidediameters. Standard
material is300 series stainless.
Internal reducingunionshave
female threadsandafittingdetail
for zerovolumefittings. Thenuts
havemale (external) threads.
External reducingunionshavemale
threads, requiringanutwith internal
threads.
External/internal and internal/
external reducingunionshave
male threadsononeendand
female threadson theother. We
recommend theuseof external/
internal fittingswhenconnecting
toanexistingexternal nut.
Internal fittingsarealmost always the
bestwith tubingof 1/8"ODor smaller.
Theymakea stronger connectionand
offer the lower volumenecessary for
highperformance instrumentation.
Also,because1/16" external fittings
havevery thin,easilydistortedwalls,
theyarenot asdurableas1/16"
internal fittings. In sizes larger than
1/8",external fittingsaregenerally
easier tomakeupbecauseof less
thread friction.
Bulkhead
versions canbemounted
throughan instrumentpanel orona
bracket. Thefittingbody isundercut
so that itbites into thepanelwhen the
mountingnut is tightened,eliminating
theneed for a lockwasher. AnO-ring
canbe installedbetween thebodyand
thepanel toallowoperation inpurged
environments. Typically themounting
nutgoes inside the instrument,so
that the long threadedportionwill be
outof sight. In theexternal/internal
bulkheadunions, themountingnut
ison the sidewith theValco internal
fitting.
deadvolume
“Deadvolume”is created inobvious
situations suchas theone shown.
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1/16"Tee
(ZT1)
unsweptvolume
Even inconnectionswhicharebymostdefinitions
“zerodeadvolume”,unswept volumemaybecreated
where large ID transitionsoccur. Theamountofmixing
dependson theamountofmismatch in the IDs.
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1/8" to1/16"Reducingunion
(ZRU21)
CHROMalyticTECHnologyPtyLtdAUSTRALIANDistributors e-mail:
: 039762 2034
