Varian 450-GC, User Manual

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Detectors – Pulsed Discharge Helium Ionization Detector (PDHID)
Page: 300 User Manual 450-GC Varian, Inc.
General Precautions
•
Do not use plastic/polymer or copper tubes for gas handling and
interconnections. Use only stainless steel tubing with Valco gold-plated ferrules.
•
Do not turn the unit on until helium discharge gas is flowing through the
detector.
•
Do not shut off or disconnect the discharge gas when the detector is hot, even if
the unit is turned off. Turn off the discharge power switch and allow the detector
to cool down naturally before disconnecting or shutting off the discharge gas.
•
Do not cover the unit with anything which could restrict air circulation.
•
Position the controller unit where the mains switch on the rear panel can be
reached easily.
Never use leak detecting flu ids on any part of the sys tem.
Installing and Purging the Helium Purifier
1. If the pressure regulator has a 1/8" male cone-type outlet port, install the
Valco 1/8" external to 1/16" internal reducer (EZR21); if it has a 1/4" male
cone-type outlet port, install the Valco 1/4" external to 1/16" internal reducer
(EZR41). For other regulator outlet fittings, a wide variety of Valco adapters
is available.
2. Remove the cap from the inlet tube of the Valco helium purifier and insert
the tube fitting into the 1/16" reducer port. (Keep the outlet tube capped.)
Use a 1/4" wrench to turn the nut one-quarter turn past the point where the
ferrule first starts to grab the tubing. Do not remove the fitting. When made
up properly, it should be leak-tight.
3. Turn the output pressure regulating knob clockwise until the gauge
registers 345 kPa (50 psi).
4. Allow 5 minutes for equilibration, then turn the regulating knob all the way
counterclockwise.