Transmissometer, also termed opacity monitor, measure the transmittance of light that passes through a flue gas. The optical system in a transmissometer is designed to captured the ratio of both intensities I / Io is the fractional transmittance. The opacity which is the primary output of the instrument is calculated through the following expression:

% Transmittance = 100% - % Opacity

or in fraction terms,

Transmittance = 1.0 – Opacity

Opacity = 1.0 – Transmittance

Opacity can be defined as “the fraction of incident light that is attenuated by an optical medium of interest” (US EPA 40 CFR 60, Appendix B).

The Opal 200 Opacity Monitoring System is designed for ease of use and maintenance and features:

Three point alignment flange and air purge inlets fitted as standard

Built-in factory calibration and test facilities.

Convenient keypad control with display at both transceiver and controller

Double pass optical system with through-the-lens (TTL) optical alignment.

Reduce maintenance down time with simple to service system design

Easily carry out service test and calibration procedures via keypad

Inbuilt air purge modules with fast clip removal

Optional O2 sensor

The OPAL 200 series opacity monitoring systems are manufactured, to the design specifications of the revised USEPA Performance Specification 1 and the associated manufacturing standard ASTM (American Standard Testing Method) D 6216-98. They are fully compliant with the requirements of the United States Environmental Protection Agency (USEPA) for industrial air monitoring.

Opal 200 opacity monitor uses double pass technology with a high powered green LED light source and offers output measurements in optical density (mg/m3) or % opacity. The unit is suitable for stack opacity monitoring in the following industries - paper mills, waste incinerators, cement kilns, power plants and refineries.