ACOUSTIC STEAM LEAK DETECTION
Acoustic steam leak detection was developed in the United Kingdom in the 1970’s. This method uses acoustic microphones to listen to a steam generator in order to detect the high pitched noises produced when there is a leak in a steam pipe.
The background noise level of a steam generator is about 60 to 75 dB depending on the design, pulverisers, burners, etc. In contrast, steam escaping through a hole one or two millimetres in size, for example, can produce noise levels of 130 dB or more at the point of origin. The noise level you will actually hear always depends on the distance between you and the source of the noise. For example: The sound pressure level curve is not linear, but exponential; a 10 dB increase in the sound pressure level corresponds to a 10-fold increase in the sound pressure, and an increase of 20 dB means a 100-fold increase of the sound pressure in comparison to the original sound level. The human ear, though, responds such that the perceived volume doubles for an increase in the sound pressure level of 10 dB and quadruples for an increase in the sound pressure level of 20 dB.
These facts must be taken into account when detecting steam leaks acoustically using high performance microphones and when interpreting the results.
PULVERIZED COAL DIFFUSERS
Breaking up the ropes of coal in the pulverised coal supply system optimises the distribution of fuel in the circular or rectangular dust lines between a mill and the individual burners.
Various setting and adjusting devices are available for fine-tuning the flow of pulverised coal.