Casella CEL Microdust 880 IS real time dust monitor - Manual (Page 44)

Microdust 880nm & WinDust Application Software
Handbook HB3255-03
Page 44 of 51
Chapter 6 - Maintenance and Servicing.
Contamination of Lenses.
As with all optical dust measurement equipment, lenses may eventually become contaminated with
particulate settling on the surface. This can reduce the instruments reading for a given dust
concentration or cause difficulty in achieving a stable zero indication.
By careful design of the optics and measurement chamber, the need to regularly clean the lenses has
been greatly reduced. If it is suspected that lens contamination has occurred (recognised by the
inability to zero or calibrate correctly), then attach the air purge pump to each probe inlet and pump
vigorously with the measurement chamber open. Any dust deposited on the surface of optical
components should be blown clear. This operation is advisable after each use to prolong the
serviceable life of the instrument.
If it is suspected that the lenses have become heavily contaminated, the instrument should be
returned to the manufacturer for cleaning and calibration.
If lens contamination is a problem then it is possible to purge the probe continuously using a source
of dry filtered air from a pump system. The flow rate to each purge inlet should be maintained at
between 0.5 and 1L/min. When continuous purging is adopted, it is necessary to draw the aerosol
through the probes measurement chamber using an aspirated technique. If this is not done then clean
purge air emerging from the measurement chamber will prevent entry of particulate matter.
Note: Warranty does not extend to cleaning or general servicing of the instrument.
Service Department.
Casella's in house service department offers a comprehensive range of repair and calibration services,
designed to effect a fast and efficient back-up for all our products. The Service Department is
operated under the scope of our BSI registration for products manufactured by us. We will however,
undertake the repair of other manufacturers equipment.
For further information please contact Casella’s Service Department at our Bedford premises. We
will be happy to provide quotations for individual repairs or provide annual maintenance under
contract.