ADS Environmental Services Eureka Digital QR 775020 A0 - Manual (Page 11)

ADS Eureka Digital System User Manual
7
C H A P T E R 2
Principles of Leak Noise Correlation
Leak noise correlation is used to detect leaks in pipes with a positive
internal pressure, where leaks allow a loss of flow to the outside. The
movement of fluid through the leak causes rapid pressure changes around
the site of the leak, establishing a noise source at the leak. This noise
travels in both directions, at the same velocity, along the pipe from the
leak. These principles are used to determine the leak location.
Note: Noise is not a constant frequency, like a musical note, but a
random and constantly changing blend of different frequencies.
The correlator operates on this principle.