How Does it Work?
How Does It Work?
A steam leak generates white noise consisting of all frequencies. However, many of those frequencies are attenuated as they travel through the gasses in the boiler. Leak noises that travel through the gasses in the boiler are known as airborne leaks. The AMS system is designed to amplify the airborne frequencies generated by a leak that show the greatest difference from the normal background noise of the boiler. The most sensitive frequency band is between 2 kHz and 11 kHz.
The AMS uses sounding rods and high temperature sensors to listen for leaks. Sounding rods attach perpendicularly, with a fillet weld, to water wall tube membranes and casing walls. Sounding rods with sensors detect leak noises that propagate through the boiler gases and through fused metal pathways. The wall acts as a diaphragm that vibrates synchronously with low frequency (2 kHz to 11 kHz) sounds that are transmitted through the boiler gases, and through fused metal pathways. The sensor converts the vibration to an electrical voltage for processing by the AFB. Lagging and other materials that rub should not touch the sounding rod or sensor.
When a waterwall leaks, the vibration caused by the leak travels through the tube, across the membrane to the sounding rod and sensor.
The noise of a sootblower sounds like a steam leak. The system uses special electronic circuits and software programming to prevent alarms from normal sootblower noise. The system will alarm if a sootblower is stuck in the boiler.