Signal Processing

Housed in a conduit box between the sensor/waveguide and the Acoustic Leak Locator system, the ALL™ Preamplifier provides the first stage of signal conditioning. An operating boiler with no leaks has a characteristic low frequency (1 kHz) rumbling sound due to combustion noise. The sound level is typically quite high. To improve the signal to noise ratio of the system, the ALL™ preamplifier is designed to filter acoustic frequencies below 1 kHz and amplify acoustic frequencies above 1 kHz. Up to 90% of the acoustic signal present is eliminated. This allows the Acoustic Leak Locator system to be set to higher sensitivities for leak detection.

The signal is sent into the self-contained Acoustic Leak Locator (ALL™) system where acoustic signal amplification and signal conditioning is completed for suitable processing. The ALL™ system’s Dual Signal Processing Unit receives the analog acoustic activity signal, processes it and compares it to preset levels and timing parameters. The results are available to the plant’s existing computer system in your required format (as 4-20 mA signal level, alarm relays, and RS232 serial i/o) for graphic display and alarms.

ALL™ provides all the data needed for a clear and accessible visual display of acoustic activity. Levels of alert are predetermined, so that when there is a significant change in activity on any channel you can know a leak has occurred.