SEPTEMBER 2004 Durag's D-UG 660 control units, used in conjunction with the D-LE 603/103 flame sensors are ideal for monitoring UV and IR flames, even under difficult operating conditions. Suitable for use in furnace plants with several burners, the system offers a selection of adjustment options including 'flame on threshold', gain and 'high-pass filter frequency'.
After startup, the control unit performs a self-test that is repeated during operation, offering improved possibilities of flame signal evaluation and a higher grade of safety and availability. Each flame sensor has a test plug for connecting a digital display, making installation and adjustment easy. By displaying the current flame intensity, the flame sensors can be aligned optimally to the flame.
For interference-free transmission through extensive cable lengths, the flame sensors convert the flame signal into strong pulses that are transmitted to and counted by the control unit. The 'flame on' indication can be set in 100 steps, and extraneous light from adjacent flames will not interfere. Parallel connection between two optical flame sensors, either UV/UV, IR/IR or UV/IR are possible. Only signals corresponding to flame flickering are processed. Flame monitoring is not influenced by ambient light, and flames where UV radiation is absorbed by dust, water vapour or other materials may be monitored in the infrared range.
IR flame sensors with a sensitivity of up to 1800 nm have been operating successfully in monitoring gas and oil combustion systems employing NOx reduction techniques such as flue gas recirculation. Durag is represented locally by OEN Enterprises.
For more information contact Mauritz van Niekerk, OEN Enterprises, 011 675 4447, mauritz@oenenterprises.co.za, www.oenenterprises.co.za
