How does the Permalert Leak Detection/Alarm system work?

The Permalert system uses Time Domain Reflectometry, rather than a short circuit, to detect a leak. A radio pulse is sent down the cable and the reflection is monitored.

When a leak occurs, the PAL-AT unit's microprocessor recognizes the change in energy reflection from the wet portion of cable and enters into alarm. A new reference map with the change is stored in memory, to allow monitoring to continue.

The PAL-AT locates the point of origin of a leak or cable fault within ± 0.1% of the sensor string length or ± 5 feet, whichever is greater. In the alarm mode, the unit activates output relays to facilitate the control of valves or remote alarms (if desired),while providing audio and visual alarms, including a digital display of the distance to the leak origin.