VICI D-4-I - Manual (Page 15)

11
Installation
The detector is usually mounted on top of the GC column oven. The cabling
as supplied requires the discharge module to be located within 0.6 m (2') of
the detector and the controller to be within 1 m (3.5') of the detector and
discharge module. The power cord for the controller is 1.8 m (6') long, and
the signal output cables (attenuated and unattenuated) are 1.2 m (4') long.
General Precautions
• Do not use plastic/polymer or copper tubes for gas handling and
interconnectons. Use only stainless steel tubing with Valco gold-plated
ferrules.
• Do not turn the unit on until the 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 both power switches (front and back
of the controller) and allow the detector to cool down naturally before
disconnecting or shutting off the discharge gas.
• Do not cover the unit with materials or devices which would restrict air
circulation.
• Position the controller unit where the mains switch on the rear panel can
be reached easily.
Mounting the Detector on the GC
Vertical Mounting
Most GCs have an existing opening which will allow the PDD to sit vertically
on top of the column oven with the column inlet manifold extending into the
oven. If you are replacing an existing detector, you can usually just remove
it and set the PDD in its place. If not, use a drill or chassis punch to drill a
hole of the proper size, and set the detector in position.
While trying to match the mounting holes of the base plate to every GC on
the market is impractical, we have located the mounting holes so that at
least two of them will coincide with existing holes on the GC. If you had to
drill a new hole to mount the PDD, you will have to drill new mounting holes
as well. Orient the detector to allow for easy cable and gas connections.
Gas Connections
Remember these three points discussed earlier: (1) all surfaces that contact
the gas stream must be fused silica or stainless steel; (2) do not use copper
tubing or brass fittings; and (3) all tubes must be thoroughly cleaned and
baked before use. The installation instructions below assume that the
detector discharge gas will be supplied from a nearby cylinder of helium of
the proper purity. If your installation is different, you may need to modify the
instructions appropriately. A number of Valco fittings have been supplied in
the fittings kit to handle different situations.