Automatic, Non-Intrusive, Flame Detection in Pipelines

Many methods of flame detection are available. Unfortunately, few offer remote, non-line-of-sight, detection. In cases where flammable mixtures are transported within tubing (such as flare lines, storage tank vents, air drilling, and improperly designed purging operations) there is often no means by which combustion can be detected. This is a significant deficiency in some applications. If the mixture were to ignite, the results could be catastrophic. To address this problem, combustion noise is being investigated at the University of Calgary as a possible means of detecting flames within tubing. An experimental study has been completed that shows that combustion noise can be distinguished from other sources of noise by its inverse power law relationship with frequency. A robust algorithm has been developed that, when combined with high-speed pressure measurements, provides early detection of flames. When combined with other filters, the algorithm can automatically separate combustion noise from other sources of noise. In this paper, a stop band filter was used to remove the noise created by a fluttering check valve.