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FPD - Flame photometric detector
Non-Ex version:
replacement of interference filter
Shut down the FPD
Disconnect two plugs from the multiplier housing:
first the detector voltage, then the signal cable
Loosen two M4 Allen screws
Place a sack or a large dark cloth over the multi-
plier housing
Carefully remove the housing and immediately
cover the light entry window with the sack or cloth
IMPORTANT
Never carry the protective pipe with the
opening pointing down. The photomultiplier
could loosen itself from the socket and be
broken.
Press the two ends of the spring wire ring together
using tweezers and lift off the ring
Remove the cover disk and filter using tweezers
Insert new filter and cover disk
Secure the filter using the spring wire ring
Replace multiplier housing and tighten the two
Allen screws
Connect the detector voltage cable and the input
signal cable
Check the dark current. If it is too large, light is
probably entering the FPD. Check the assembly!
Non-Ex version:
replacement of photomultiplier
Remove the multiplier housing as described in Re-
placement of interference filter
Loosen the two flat-head screws
Carefully pull the protective cover and the protec-
tive pipe apart
Pull back the shielding plate by 5 cm and pull the
photomultiplier tube out of the socket.
Tilt the shielding plate to the side and pull the
photomultiplier tube out of the shielding plate
Insert new photomultiplier tube in reverse sequence.
Avoid bright light
Insert the grounding cable of the shielding plate
completely between the photomultiplier tube and
securing ring such that the shielding plate is flush
with the securing ring
Push the protective pipe over the photomultiplier
and shielding plate. Make sure it is centered.
Screw on the protective pipe and protective cover
4 - 30
Measure the resistance of the detector voltage
socket against the housing: setpoint 11.5
Eliminate a short-circuit if present before connect-
ing the detector voltage
Push the photomultiplier with protective pipe onto
the heat sink as far as possible and screw tight
Connect the detector voltage and input signal cables
Check whether the detector is light-proof: the basic
current must not be smaller than when the FPD is
covered with a dark cloth
Check the measuring sensitivity and selectivity
using a test mixture
Non-Ex version: cleaning the quartz
disk, combustion chamber, reflector
Shut down the FPD
Remove the photomultiplier as described under Re-
placement of photomultiplier
Unscrew heat sink from center part and lift up mo-
dule cover
Wipe quartz disk using a damp cloth. Use alcohol if
necessary. CAUTION: do not scratch the quartz
disk!
Unscrew zhe holder and replace the quartz disk if it
is dull. Take care with the graphite gasket
Unscrew ignition electrode and clean shaft
Unscrew the exhaust gas line
Wipe the center part and reflector using a damp
cloth. If stubborn dirt remains on the parts, remove
the parts and soak them in solvent or a pickling sol-
ution. Polish the reflector. Rinse with methylene
chloride and dry the parts in a compressed air
stream
Refit the reflector and center part, install the ex-
haust gas line and ignition electrode. Adjust the ig-
nition electrode on the side above the combustion
chamber. The spark path should be approx. 5 mm
long.
Reassemble detector and start up as described
above. Check the dark current, basic current and
sensitivity.
FPD - Flame photometric detector
MΩ.
EXFPD.CHP
Stand September 14, 1999
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