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A fuel leakage detection system for an underground fuel piping system having fuel service pits installed at locations along the piping. Each pit has a pressure sensor and a reference electrode positioned external to the pit assembly for continuous and automatic monitoring of fuel pressure and pipe-t

A fuel leakage detection system for an underground fuel piping system having fuel service pits installed at locations along the piping. Each pit has a pressure sensor and a reference electrode positioned external to the pit assembly for continuous and automatic monitoring of fuel pressure and pipe-to-soil potential measurements of an impressed current cathodic protection (ICCP), and each pit assembly includes a processor and a transceiver. The system provides simultaneous and synchronized pressure and ICCP potential measurements which are transmitted over a wireless network to a control station that performs accurate location of a leakage point in the underground piping and can detect pressure loss during fueling operations which produce strong pressure transients that normally mask detection of pressure loss in the fuel piping, and can determine a leak in the piping and its location by analyzing the pipe-to-soil potentials taken on the fuel piping and pressure losses occurring between transients.

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1. Apparatus for detecting fuel leaks in an area having at least one fuel service pit assembly for managing fuel flow from an underground fuel pipeline, the at least one fuel service pit assembly including at least one sidewall having an inlet for receiving a connecting pipeline in fluid communicati

1. Apparatus for detecting fuel leaks in an area having at least one fuel service pit assembly for managing fuel flow from an underground fuel pipeline, the at least one fuel service pit assembly including at least one sidewall having an inlet for receiving a connecting pipeline in fluid communication with the underground fuel pipeline, and a pit cover for accessing the at least one service pit assembly, the leak detection apparatus comprising: a potential reference electrode respectively buried in direct contact with ground soil proximate each of the at least one fuel service pit assemblies;a test point defined at a local section of the pipeline;said at least one fuel service pit assembly further comprising: a local signal processor coupled to memory for communicating and storing present and previous pipe-to-soil potential measurements during fueling and non-fueling operations, said signal processor configured to receive a first electrical signal indicative of an electrical potential from the potential reference electrode and a second electrical signal indicative of an electrical potential at the local section of the pipeline, wherein a pipe-to-soil potential is defined by a voltage potential difference as between the test point and the potential reference electrode, said signal processor operable to preprocess the pipe-to-soil measurements by receiving sample pipeline and soil electrical potential measurements at predetermined intervals, calculating an average pipe-to-soil potential value based on the sample pipeline and soil potential measurement values, and comparing the latest sample pipe-to-soil potential measurement with the average pipe-to-soil potential value;a local transceiver communicably coupled to the local signal processor for receiving the preprocessed pipe-to-soil measurements from the signal processor; anda central control station having a central transceiver for receiving said preprocessed pipe-to-soil measurements from the local transceiver over a communications network, and a central processor for further processing said preprocessed pipe-to-soil measurements received from the at least one fuel service pit assembly to detect and locate the position of a fuel leak in the underground fuel pipeline. 2. The apparatus of claim 1, wherein the pit cover comprises a watertight and heat-resistant housing mounted to its underside and configured to enclose the local signal processor and the local transceiver. 3. The apparatus of claim 2, wherein the at least one fuel service pit further comprises: a pressure sensor mounted within said housing;a vent valve coupled to the underground pipeline via the connecting pipeline; anda capillary tube coupled between said pressure sensor and the underground pipeline, wherein the capillary tube is flexible and extends a length sufficient to permit personnel access to the service pit assembly through the pit cover. 4. The apparatus of claim 3, wherein the vent valve is coupled to the underground pipeline by a vent pipe connection having a distal end mounted to the pipeline, a maintenance valve mounted to the opposing proximal end of the vent pipe connection, and a T-fitting mounted between the maintenance valve and the vent valve, and wherein the capillary tube has a first end mounted to the T-fitting and the opposing second end communicably coupled to the pressure sensor. 5. The apparatus of claim 3, wherein the local signal processor receives pressure measurements from the pressure sensor at predetermined intervals and performs pattern recognition routines to determine the occurrence of fueling operations and non-fueling operation. 6. The apparatus of claim 3, wherein the local signal processor is operable to compare current pressure measurements with previous pressure patterns obtained during fueling operations. 7. The apparatus of claim 1, wherein the first and second electrical potential signals are provided through first and second electrical conductors which are enclosed in a flexible conduit having a length sufficient to permit the opening and closing of the pit cover. 8. The apparatus of claim 1, wherein the at least one fuel service pit assembly is one of a vent pit assembly or a valve pit assembly. 9. The apparatus of claim 1, further comprising a switch having an actuator coupled to the pit cover that permits power flow to the local signal processor and local transmitter when the pit cover is closed, and disables power flow to the local signal processor and local transmitter when the pit cover is opened. 10. The apparatus of claim 1, wherein said at least one fuel service pit assembly comprises a plurality of service pit assemblies, and wherein the central control station further comprises: a memory coupled to the central processor; anda pipeline leakage detection program stored in the memory and executable by the central processor, the pipeline leakage detection program operable to: receive preprocessed pipe-to-soil potential measurements from adjacent service pit assemblies transmitted over the communications network from each of the plurality of service pit assemblies at predetermined intervals;determine whether the pipe-to-soil measurements at adjacent service pit assemblies have changed proportionally; andif it is determined that the pipe-to-soil potential measurements deviate from patterns associated with non-leakage conditions, the pipeline leakage detection program is further operable to:provide an alert condition to operating personal indicative of a pipeline leak;determine the location of the pipeline leak based on a distance between the present pipe-to-soil potential and the previous pipe-to-soil potential patterns at each service pit assembly location; anddetermine appropriate low pressure alarm set points for fuel pumps that control fuel flow through the underground pipeline. 11. The apparatus of claim 10, wherein the location of the leak is determined by comparing present pipe-to-soil potential and the previous pipe-to-soil potential patterns at each service pit assembly location. 12. The apparatus of claim 1, further comprising a wireless antenna mounted within a cavity formed in the pit cover, wherein said wireless antenna is communicably coupled to the local transceiver for receiving and transmitting information wirelessly over the wireless network. 13. The apparatus of claim 1, wherein the pit cover includes a power supply assembly comprising at least one solar cell mounted in a compartment formed within the outer surface of the pit cover, a battery charger electrically coupled to receive electrical current from the at least one solar cell, a rechargeable battery electrically coupled to the battery charger, and a switching control circuit for controlling power to the local signal processor and the transceiver. 14. The apparatus of claim 1, wherein the pit cover further comprises a wireless antenna mounted under a protective high- compression resistant non-metallic cover formed on the top surface of the pit cover, said antenna being electrically coupled to the transceiver via a cable. 15. The apparatus of claim 1, wherein the local signal processor is operable to perform signal conditioning and noise filtering in order to reduce the level of noise produced by fueling operation and fuel surges. 16. The apparatus of claim 1, wherein the local signal processor is operable to detect negative pressure peaks caused by leaks and impressed current cathodic protection pipe-to-soil potential loss determination. 17. The apparatus of claim 1, wherein the central processor is operable to: receive, from each local signal processor installed at each fuel service pit, the pre-processed signals associated with local pressure measurements; andperform pattern recognition to detect pressure losses in the pipeline. 18. The apparatus of claim 1, wherein the central processor is operable to: receive, from each local signal processor installed at each of the at least one fuel service pit assembly, the preprocessed pipe-to-soil measurements; andcalculate differences of electrical potential loss measured at adjacent fuel service pits. 19. The apparatus of claim 1, wherein the central processor is operable to: monitor pressure loss rate at each local service pit assembly; andadjust pressure level alarms based on aircraft fueling operations. 20. The apparatus of claim 1, wherein the central processor is operable to: determine drops in electrochemical potential along the underground fuel pipeline from adjacent service pits;compare the drops in electrochemical potential to historical electrochemical potentials at each service pit; andidentify a leakage condition between adjacent service pits when the comparative drops in electrical potential exceed a predetermined value. 21. The apparatus of claim 1, wherein the at least one fuel service pit assembly further comprises a cover switch having an actuator that interrupts power flow to the local signal processor and local transceiver when the pit cover is in an open condition. 22. The apparatus of claim 1, wherein the communications network comprises a wireless communications network. 23. A method for detecting fuel leaks in an area having at least one fuel service pit assembly for managing fuel flow from an underground fuel pipeline, the at least one fuel service pit assembly including at least one sidewall having an inlet for receiving a connecting pipeline in fluid communication with the underground fuel pipeline, a pit cover for accessing the at least one service pit assembly, the pit cover including a local signal processor coupled to memory for communicating and storing present and previous pipe-to-soil potential measurements during fueling and non-fueling operations, the local signal processor being communicably coupled to a local transceiver for communicating pressure and electrical potential measurements to a central control station over a communications network, a test point defined at a local section of the pipeline, and a potential reference electrode respectively buried in direct contact with ground soil proximate each of the at least one fuel service pit assemblies, the leak detection method comprising: receiving, at the local signal processor, a first electrical signal indicative of an electrical potential from the potential reference electrode and a second electrical signal indicative of an electrical potential at the local section of the pipeline, wherein a pipe-to-soil potential is defined by a voltage potential difference as between the test point and the potential reference electrode;preprocessing pipe-to-soil measurements by receiving sample pipeline and soil electrical potential measurements at predetermined intervals, calculating an average pipe-to-soil potential value based on the sample pipeline and soil potential measurement values, and comparing the latest sample pipe-to-soil potential measurement with the average pipe-to-soil potential value;communicating the preprocessed pipe-to-soil measurements from the signal processor to the local transceiver;transmitting the preprocessed pipe-to-soil measurements to the central control station over the communications network; andprocessing, at the central control station, said preprocessed pipe-to-soil measurements received from the at least one fuel service pit assembly to detect and locate the position of a fuel leak in the underground fuel pipeline.