Patent Document

CROSS-REFERENCE 
       [0001]    This is a Non-Provisional Application of U.S. Provisional Patent Application Ser. No.: 60/932,074, filed on May 29, 2007, the entire content of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    I. Field 
         [0003]    This disclosure is related to leak detection. More particularly, this disclosure is related to leak detection for pressurized systems. 
         [0004]    II. Background 
         [0005]    Leak detection is important for several reasons, including for example loss of potable water from pressurized delivery lines and spills caused by pressurized sewage lines. Traditional methods of leak detection rely upon visual inspection of lines and evidence of leaks around the pipes, such as visible moisture, sink holes, smells from sewage spills, decreased water flow at the end point of the pipe, etc. Severe sewage spills indicate the need for a rapid assessment of pipe integrity and leakage from holes or cracks in pipes. 
         [0006]    In view of the above needs, the present disclosure describes novel systems and methods to rapidly detect leaks in pressurized lines such that the existence, location, and severity of these leaks can be immediately relayed to appropriate authorities, thus minimizing the environmental and economic consequences of the leak. 
       SUMMARY 
       [0007]    The foregoing needs are met, to a great extent, by the present disclosure, wherein systems and methods are provided that in some embodiments facilitate a detection of leaks in a pressured pipe, comprising: one or a plurality of pressure sensors, placed at one or several locations along the pipe; a power source providing power to the one or plurality of pressure sensors; a computer; a communications device; and an algorithm to assess data received from the communications device, the data containing information from the one or plurality of pressure sensor(s), wherein the algorithm determines the presence of a pressure leak in the pressurized pipe based on a first pressure profile versus a second pressure profile. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]      FIG. 1  shows a schematic layout according to an embodiment of the disclosure. 
           [0009]      FIG. 2  shows an example of pressure profiles. 
           [0010]      FIG. 3  shows an example of pressure profiles during periods of pumping. 
           [0011]      FIG. 4  shows a diagram of a leak detection assessment according to an embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The disclosed methods and systems below may be described generally, as well as in terms of specific examples and/or specific embodiments. For instances where references are made to detailed examples and/or embodiments, it should be appreciated that any of the underlying principals described are not to be limited to a single embodiment, but may be expanded for use with any of the other methods and systems described herein as will be understood by one of ordinary skill in the art unless otherwise stated specifically. 
         [0013]      FIG. 1  shows a schematic diagram  100  according to an embodiment of the present subject matter. A pressurized pipe  105 , which could be a water line or sewer line, or other type of transmission line including oil or gas, carries liquid under pressure through the pipe  105 . A pump  110  (or also a series of pumps) provides pressure at one end of the pipe to force the liquid through the pipe  105 . One or a multiple of pressure sensors  120  are placed at various positions along the pipe  105 , contact the liquid in the pipe  105  either directly or through a pressure-loss free connector, and continuously or periodically measure instantaneous pressure in the pipe  105 . The locations may be along the pipe, around the pipe, or both, and may create a functional form of location that optimizes the pattern recognition measurements from the sensors  120 . Each pressure sensor  120  is has a communications connection  130  (wired or wireless) to an instrumentation unit  140 . While  FIG. 1  shows communications connection  130  in a wired configuration, the present disclosure also contemplate the communication connection in a wireless configuration. The instrumentation unit  140  may contain some or all of the following items: a power supply; a (micro)processor; an analog to digital (A/D) converter; a digital clock; a two-way wireless communications means such as a pager; cell phone or other communications device; software; environmental packaging (e.g. NEMA 6P) and communications ports. Of course, more or less items may be part of the instrument unit  140 , according to design preference. 
         [0014]    In certain embodiments, this instrumentation unit  140  has a power supply which for example without limitation may be a replaceable primary battery, as a non-limiting example, a lithium thionyl chloride battery package with long shelf life, connected to a separate environmental enclosure that contains the power electronics, the microprocessor, the A/D converter, and the wireless radio. The battery package may also be environmental, and may include circuitry that limits rapid discharge of the batteries in order to minimize or eliminate sparks if the battery is short-circuited, and may also include “smart-battery” circuitry that continuously measures the effective discharge of the battery package and enables the lifetime of the batteries to be determined externally and remotely. The connection between the battery package and the electronics enclosure may be achieved through a rugged waterproof connector, typically one that is used, for example, in the automobile industry. Other power sources may also be AC power, solar power, fuel cells, electromechanical power sources, or other power supplies. 
         [0015]    Referring again to  FIG. 1 , data collection, data processing, and two-data communications processing takes place in the instrumentation unit  140 . Communications means  150  is a two-way link between instrumentation unit  140  and a larger, more global communications network  160 , which may be a wireless network such as a cell phone or two-way pager network. Communications means  170  is a two-way link between the communications network  160  and a local communications device  180  that typically would sit with a user, for example, a cell phone, two way pager, personal data assistant (PDA), personal computer, or other capable one way or two way communications devices. 
         [0016]    The communications means  150  and  170  may comprise any form of wireless or wired communication protocol, device, mechanism, system, and so forth. Thus, digital and/or analog transmissions can be used via the communications means  15  and  170  according the design implementation. Depending on the resources available to the managing entity, various frequencies (either singly or multiply) may be used for communication information between the instrumentation unit  140 , communications network  160  and local communications device  180 . 
         [0017]    Instrumentation unit  140  may operate in one or more of several modes. A first mode is an “alarm” mode, in which the microprocessor in the instrumentation unit  140  makes a determination that the pressure profile from the single or multiple sensors has generated a unique signature indicating that a leak has occurred. In this mode, an alarm is sent through wired or wireless means  150  to a communications network  160 , which then further processes the data, for example determining the location from where the alarm originated and to where the alarm is to be sent, and sends this data via wired or wireless means  170  to a local two-way communications device  180  that allows the action to be taken to respond to a leak. 
         [0018]    It should be noted that the communications network  160  may be connected to the Internet or other network resource. Similarly, the communications device  180  may be connected to the Internet or other network resource. Connection to the communications network  160  and communications device  180  may also be facilitated via a host or local server, according to design implementation. In this instance, the server may act as a central server and may parse information from the various devices attached to the network. Based on the “type” of device communicating to the server, the server may forward different status or different priority messages or use a different communication means to forward information to the communications device  180 . Accordingly, information warranting a rapid response may be sent via a page, versus information that does not require a rapid response, for example. 
         [0019]    In certain embodiments, the instrumentation unit  140  sends messages though a two-way paging network  150 , such as those operated by Skytel (Clinton, Mo.), USA Mobility (Plano, Tex.) or Space Data (Chandler, Ariz.), as non-limiting examples of commercial/private providers, to a dedicated server  160 , which sends data through the internet to portable devices  180  such as pagers, cell phones, PDAs, and so forth, and also posts this data on a secure web site to be viewed by users of the system, in which the communications devices  180  are computers with Internet access. 
         [0020]    A second mode is a “reporting” mode, in which pressure data is taken on a periodic basis from each of the pressure sensors  120  and stored in the instrumentation unit  140 . On a periodic basis, the instrumentation unit  140  spontaneously transmits the stored data through communication means  150  to the communications network  160  and finally through communications means  170 , to a user communications device  180 . 
         [0021]    A third mode is a “control” mode in which commands may be sent in the “reverse” direction from communications device  180  through the communications means  170  and network  160  to instrumentation unit  140 . These commands are processed by the microprocessor in instrumentation unit  140  and cause the instrumentation unit to modify some aspect of operations. 
         [0022]    Examples of a control mode could include, without limitation: turning sensors on or off; changing the frequency at which the sensors take pressure measurements; changing the internal operating software of the instrumentation unit; changing the frequency at which the instrumentation package sends historical data; changing the algorithms that determine if a leak has occurred; and changing the content of the data that is sent from the instrumentation unit periodically. 
         [0023]    A fourth mode is a “maintenance” mode in which maintenance data representing environmental parameters such as, for example, temperature and humidity or operating parameters of the system, including, for example, pressure sensor  120  operations, power supply voltage, communications level (e.g. received signal strength indicator); and other diagnostic operation parameters are sent from the instrumentation unit  140  to the user communication device  180  on either an alarm basis or a periodic basis. 
         [0024]    A fifth mode is a “request” mode in which a user, through the communications device  180 , may request current pressure, environmental, operational performance and/or maintenance parameter values or other data in the “reverse” direction through communications means  170  to the communications network  160 , through another communications means  150 , finally to the instrumentation unit  140 . Software in the instrumentation unit  140  can cause a real-time measurement of requested parameters and sends the results immediately back through the communications means to the data collection/reception device  180 . 
         [0025]    Since indication that a leak has occurred or is occurring is one of the most important aspects, the means by which a leak is detected is a critical part in addressing this issue. Two cases are considered: a static case in which the fluid in the pipe is quiescent (not pumped), and a second in which the fluid in the pipe is experiencing normal or typical pumping conditions. 
         [0026]      FIG. 2  shows an example  200  of data generated by pressure sensors in a quiescent condition that may be used by instrumentation unit  140  to process pressure data received to make a determination that a leak has occurred in a pressurized pipe, such as a force main in a sewer system. Consider pressured pipe  105  in  FIG. 1  that has a natural upward slope from the pump  110 . If the pump  110  were turned off for a period of time, the pressure as a function of time can be measured at various locations along the pipe, generating a graph  200  like that shown in  FIG. 2 . 
         [0027]    A pressure profile like that shown in  210  in  FIG. 2  indicates that there are no leaks, as the static pressure in the pipe stays constant over time. Pressure profiles  220  and  230  could occur is there is a leak along the section of the pipe between the pressure sensors and the top of the pipe. In the case of pressure profile  200 , a leak is farther from the pressure sensors and higher on the pipe than a leak indicated by pressure profile  300 . By combining measurements from several pressure sensors, a small leak at a specific location can be identified. In addition, in some embodiments when the pumps are turned off, an active acoustic signal can be generated, and the signal analyzed using methods listed below to determine whether or not a leak exists in the pipe. 
         [0028]      FIG. 3  shows an example  300  of data generated by a pressure sensor at a specific location on a pressurized pipe during periods of pumping. Curve  310  corresponds to an example of how the pressure may vary over time under normal operating conditions, with no leak in the pipe. The maximum pressure is indicated by the horizontal line  315 . Under leak conditions, a pipe will not be able to maintain the same pressure profile, and the leak will manifest itself in a pressure profile signature that is different than normal operating conditions. This signature will vary depending upon the location of the pressure sensor, the location of the leak, the pump(s) operational performance, and the hydrodynamic details of the pipe and hole causing the leak. As one simple example, the maximum pressure would drop under a leak condition. For example, curve  320  corresponds to a leak condition as measured by a pressure sensor. In this case, the curve has a somewhat different profile, but most markedly, does not have the same maximum value  325  as the non-leaking case. 
         [0029]      FIG. 4  shows a schematic diagram  400  of how certain embodiments use multiple pressure sensors to make a decision about whether or not a leak is present. The pressure sensors  120 , per  FIG. 1 , are placed at various locations along the pipe  105 . Baseline (normal, non-leak) measurements are made to determine the “pressure signature” of the pipe  105  as a function of time, operating parameters and location along the pipe. The variability of these signatures is captured in the data collected by sensors  410  in  FIG. 4 . When a leak occurs, it creates a signature that is determined by the algorithm  420  to be significantly different enough from the baseline that an alarm is generated  460  and sent to a user, per the system shown in  FIG. 1 . Various signal processing and pattern recognition techniques can be applied to this problem, including, but not limited to the following:
   Least mean squares   Analysis of Variance (ANOVA)   Multiple analysis of variance (MANOVA)   Matched filter(s)   Numenta   Neural networks   Bayesian analysis   Rules engine   Fourier/frequency analysis   Kalman filtering   Hamming filtering   Auto-correlation   Cross-correlation   Heuristic algorithms     
         [0044]    Analysis of the dynamic pressure conditions may also include contemporary data collected directly from the pumps used to pressurize the pipe, in order to minimize false positives and increase the fidelity of the decision-making process. Optimization of an applicable algorithm can be performed to reduce the number of false positives or false negatives. 
         [0045]    It should therefore be appreciated that given the teachings provided herein, one of ordinary skill may be able to monitor the integrity of a sealed transport systems, such as pressurized pipes, for example. As such, methods and systems have been disclosed that enable the described embodiments to be applicable for fluid conveying systems as well as gas conveying systems, or a combination of the two. Also, while the context of the embodiments are described in terms of pipes, other vessels or conveying constructs may be used according to design preference. It should also be noted that while  FIGS. 2-3  shown a certain pressure “profile,” other profiles may be relevant according to design. 
         [0046]    Additionally, the methods and systems may be implemented by various devices. For example, the identification algorithm  420  of  FIG. 4  may be processed by a computer or hardware or analogy thereof. Stand alone or distributed systems may be configured. Single or multiple types of processing engines may be used, such as application specific integrated circuits (ASICS), digital signal processors (DSPs), programmable logic devices (PLDs), microcontrollers, microprocessors and other forms of electronic or electrical devices capable of operating as a decision or execution engine. Further, networking of such systems or hardware may be envisioned according to design implementation. In some embodiments, software for operation of the exemplary methods and systems may be integrated into the hardware platform, or may be distributed. Accordingly, serial or parallel or a combination of the two, including neural or cloud computing approaches may be used. Thus, communication between various aspects of the embodiments described herein may be hardwired or wireless, or combinations of the two. 
         [0047]    Additionally, each or several of the various elements of the embodiments described may be contained in an environmentally secure enclosure. In some instances, the embodiments may have selective elements within the enclosure and selective elements outside the enclosure. For example, the pressure sensors may be exterior to the enclosure while the instrumentation unit  140  and/or the communications means  150  may be interior to the enclosure, for example. Thus, elements that need to be protected can be protected via the environmental enclosure. 
         [0048]    As varied as the hardware implementation can be, modifications or variations of the software algorithm  420  may be similarly performed without departing from the spirit and scope. Therefore, improvements to or combinations of the listed signal processing and pattern recognition techniques may be used, according to design implementation. As the listed techniques are not intended to exhaustive, but to illustrate the breath of applicable techniques, other techniques not described herein can also be used. 
         [0049]    What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.

Technology Category: 3