Land 4500 MKII Premier, Operation And Maintenance Manual

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Model 4500 Premier Dust and Opacity Monitor
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During the regularly scheduled maintenance periods, any optional equipment (e.g. shutters, pressure
switches, weathercovers) should be checked for correct operation. If any potential problems are
noted, the equipment should be repaired or replaced if necessary.
Cleaning the Optical Surfaces
After prolonged use, it is likely that some contamination will occur on the optical surfaces of the Model
4500 Premier. 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. Three
optical components should be cleaned, using the lens cloth supplied by Land Instruments International.
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 Premier. 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. Undo the two socket headed, captive screws holding the zero-point assembly and carefully
remove it. Wipe the lens using the lens cloth, then replace the zero-point assembly. Lift the spring-
loaded protective cover over the zero-point reflector and wipe the reflector. Gently replace the
protective cover. Close the housing and fasten the quick-release clamps.
CAUTION
Do not attempt to move the zero-point reflector by hand. The precision gearbox
will be irreparably damaged.
Cleaning the Termination Box
It is recommended to periodically clean the termination box to remove any build-up of dirt or dust,
which may enter the box if the door is opened.