摘要 |
A cathodic protection monitor is disclosed to be electrically connected to a cathodic protection rectifier that is adapted to prevent rust, corrosion and possible leakage in an underground pipe or storage tank above which the rectifier is supported. The cathodic protection monitor includes a CPU that reads, digitizes and stores analog current and voltage signals which are supplied from the DC output of the rectifier and are indicative of the effectiveness thereof. The monitor includes an ISM band transceiver and antenna by which the CPU is polled and from which packets of stored data are transmitted to a data collector at an overhead airplane or nearby motor vehicle for retransmission and analysis by the pipe owner or maintenance crew. Synchronized timing signals are supplied (from the National Bureau of Standards) to a stable auxiliary clock by way of a WWVB transceiver and antenna. The auxiliary clock from each of a plurality of cathodic protection monitors along the pipeline provides a synchronized clock control signal to a respective CPU which, in turn, generates a switched relay control signal to a relay of the cathodic protection rectifier. Accordingly, the relays of all of the cathodic protection rectifiers can be simultaneously energized and de-energized during successive time periods so that all of the cathodic protection rectifiers can be turned on and off at the same time as may be required to compile ground voltage readings along the pipeline as part of a government-mandated survey.
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