Ametek Land 4500 MKIII, User Manual

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C - 7
Model 4500 MkIII Opacity and Dust Monitor
User Guide
C6 Physical Principles
C6.1 General Description
The Land Instruments International Model 4500 MkIII Continuous Opacity
Monitoring System (COMS) measures opacity by shining a light beam
through flue gases. An internal microprocessor calculates opacity, dust
density and other parameters. The instrument comprises the following
parts. The Transceiver which contains all of the optical and electro–optic
components; the Retro-Reflector containing a glass reflector and the air
purge system.
The air purge system can take several forms depending upon individual
site requirements. Single and dual electric blowers are available, as are
compressed-air driven devices. Continuous purge air supply is essential
to prevent dust and corrosive gases from affecting the optical system.
Automatic fail–safe shutters can also be fitted for temporary protection in the
event of a purge air failure.
The entire system is designed for continuous operation in all weather
conditions, with minimal maintenance.