Ametek Land 4500 MKIII, User Manual

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Opacity and Dust Monitor
User Guide
Model 4500 MkIII
E - 4
Cleaning the Optical Surfaces
After prolonged use, it is likely that some contamination will occur on the
optical surfaces of the Model 4500 MkIII. The time taken for significant
contamination to occur depends very much on the nature of the installation,
but in a typical situation it should be sufficient to clean the optics every 90
days.
CAUTION
Always use a lint free lens cloth to clean the optical surfaces.
Ensure the cloth is kept clean. A dirty lens cloth can scratch the
optical surface and cause permanent damage to the Model 4500
MkIII. Replacement lens cloths can be purchased from Land
Instruments International. Ordinary tissues and dusters are
not suitable, and can scratch the delicate optical surfaces.
To clean the Retro-Reflector, open the housing by undoing the two quick-
release clamps. Carefully wipe the glass surface of the Retro-Reflector with
the lens cloth. Close the housing and fasten the two quick-release clamps.
To clean the mains lens, open the Transmissometer housing by undoing
the two quick-release clamps. Wipe the lens using the lens cloth. Close the
housing and fasten the quick-release clamps.
CAUTION
Do not attempt to move the zero reflector by hand. The precision
gearbox will be damaged irreparably.
E3 Locking the Fail-Safe Shutter Open
If the fail-shutter develops a fault and will not open automatically, it is
possible to lock it in the open position as follows:
1) Remove the cover from the shutter
2) Identify the locking screws (circled) and
remove them using a 2 mm hex key.
3) Remove the spacers and replace the screws
loosely. Do NOT tighten them at this stage.
4) Using a 2 mm hex key, remove the grub
screw in the bottom of the shutter flange.
5) Insert a rod or narrow screwdriver into the
screw hole and push the shutter fully open.
6) With the shutter held open, tighten the two
locking screws.
7) The shutter will remain open.