Varian 450-GC, User Manual

Page: 170 / 205

Detectors – Pulsed Flame Photometric Detector (PFPD)
Page: 410 User Manual 450-GC Varian, Inc.
Tools and Equipment Needed
These tools are needed to complete the following procedure:
•
Phillips-head screwdriver.
•
Glass filter in filter holder.
•
Lab tissues.
•
Capillary pick.
Disassembl e the PFPD and Remove the Optic al Filter
1. Turn OFF the PFPD electronics.
2. Remove the Detector cover from the top of the GC.
3. Remove the 2 thumbscrews holding the PMT housing (Item 4) to the light
pipe assembly (Item 5). Carefully remove the PMT housing from the
detector tower. The filter (Item 6) is loosely held in the filter holder (Item 7)
that is recessed in the end of the PMT housing.
4. Invert the PMT housing over a clean lab tissue and allow the filter holder to
drop out of the recess in the end of the PMT housing. If the filter holder
should stick in the PMT housing, free it by using gentle pressure with a
capillary pick or other clean utensil. Place this filter on a clean surface (e.g.,
lab tissue) or in its storage container.
Handle the filter holder by its outside edge. Do not touch the optical
surface of the filt er.
Replace the Optic al Filter
1. If you are cleaning the optical filter , remove the C-clip holding the filter in
the filter holder. Moisten a clean lab tissue with methanol or iso-propanol.
Hold the filter by its outer edge and gently wipe both surfaces of the filter
with the lab tissue. Wipe away the excess solvent with a clean dry lab
tissue. Place the filter in the filter holder and reinstall the C-clip.
2. Hold the filter that is to be installed by its outside edge and slide it into the
recess in the end of the PMT housing. Check that the filter is correctly
seated so that its surface is flush with the rim of the PMT housing and the
O-ring (Item 8) is properly seated in its groove.
3. Carefully join the PMT housing to the light pipe assembly and install and
tighten the 2 thumbscrews.