Opacity Monitors

Our continuous opacity monitors use the standard obscuration technique to measure the transmission of a light beam from one side of a stack to the other.

This non-contact optical measurement technique offers excellent reliability as it requires no moving parts and no intrusion into the harsh atmosphere of the stack. The light beam is provided by a long life LED source which is modulated at a fixed frequency to guarantee complete immunity from ambient light sources.

The transmission value can be translated and displayed in a variety of derived units including opacity (%), volumetric density (mg/m³), Ringleman, meteorological optical range (MOR), and extinction. All our opacity monitors include maintenance and level alarm contacts, isolated 0-10V and 4-20mA analogue outputs, and serial comms in the form of RS232/RS485 for flexible integration into any CEMS or factory system.

The measurement heads (transmitter and receiver) are equipped with an air purge facility for maintaining clean optical surfaces and preventing in rush from positive pressure stacks. The heads also offer quick release clips for ease of maintenance, and stainless steel construction for advanced corrosion resistance.

Typical applications include:

• Boilers
• Incinerators
• Crematoria
• Power Stations
• Furnaces
• General combustion processes
• Bag houses
• Air filtration units
• Electrostatic precipitators
• District heating plants
• Pulp and paper
• Air transport systems
• Road, rail and service tunnels