GB2553833B - Pipe condition assessment device and system - Google Patents

Description

PIPE CONDITION ASSESSMENT DEVICE AND SYSTEM

FIELD OF THE INVENTION

This invention relates to a pipe condition assessment device which may be connected to an isolated section of a pipe network such as that of a water reticulation system of a municipality or other water supply authority herein referred to as a ‘network section’ for the purpose of assessing the condition of the network section from the point of view of assessing leakage from pipes and fittings within the network section. The invention also relates to a system in which water loss for different network sections can be processed and remedial action suggested, preferably with an indication of the severity of water loss in a particular network section.

The device, method and system of the invention may be used by municipalities, contractors or other parties for the purpose of determining the characteristics of network sections of a water distribution network or other fluid pipeline system and implementing remedial action.

BACKGROUND TO THE INVENTION

Water loss in water distribution networks making up a reticulation system is a huge problem internationally with a large proportion of water entering a distribution system being lost through pipe or fitting leaks. Water demand is generally increasing due to population growth and urbanisation, and water resources are coming under greater stress with water supply failures becoming more commonplace. In many areas there is a loss of water entering a distribution network of from 20 to 30 % and even more in some instances. Added to this is the shortage in many less affluent countries of qualified staff for combating such a problem and for fixing the water leaks as may be appropriate.

There are many technologies available for detecting and assessing leakage in isolated pipe sections of a pipe network. None of them, however, provides sufficient functionalities in a single solution. They also tend to be less suitable for some water distributors, being expensive and requiring skilled technicians. Additionally, the size of leak that can be detected is rather large. A thorough review of leakage management has been performed by Puust et al. (2010). The authors separated two concepts, leakage assessment and leakage detection. The two concepts with example technologies will be discussed separately below.

To determine the real losses, two common techniques performed are a 24 hour zone flow measurement, and a minimum night flow analysis. From these techniques, it is possible to estimate the volume of real losses. For more accurate estimations, a tested section is sometimes characterised in terms of flow versus pressure head. By doing the characterisation, the leakage volume can be more accurately calculated over a period with varying pressure. It is common for systems to be characterised in terms of a power equation sometimes known as the N1 power equation which is as follows:- Q=c.hm in which N1 refers to the leakage exponent, Q the flow rate, h the pressure head, and c is a leakage coefficient.

Existing devices are used to test pipes for the existence of leaks, but do not provide information that is able to estimate the properties of the leak.

Of the two techniques, minimum night flow disrupts the network the least, since isolation of the tested section is not needed. Minimum night flow measures the flow rate into a district metered area (DMA) when the diurnal flow pattern reaches a minimum, typically between 2h00 and 4h00, and subtracts the legitimate night flow to determine the leakage flow rate (Liemberger & Farley, 2004). Combining this information with the pressure at the time, the DMA leakage exponent can be determined.

With leak detection, the priority is to determine if there is a leak and to determine the location of the leak. The effectiveness of these techniques is determined by how small a leak it can detect, how precisely it can determine the leak location, and how often false positives occur (Cist & Schutz, 2001). These are important considerations, since resources will be spent on fixing the perceived leak, and it can be a costly exercise if located incorrectly.

Puust et al. classified leak detection techniques into two groups, namely leak localisation and leak pinpointing. Localisation techniques are those that can give a general indication as to where the leak is located, while pinpointing techniques locate the leak to within a meter. The pinpointing techniques tend to be costlier and/or more time consuming, and therefore Puust recommend that the pinpointing techniques be used in conjunction with the localisation techniques. Localisation techniques include step-testing, acoustic logging, and ground penetrating radar, amongst others. The pinpointing techniques considered by Puust are leak noise correlators (LNC), trace gas injection testing (TGT), and pig-mounted acoustic (PMA) sensing.

The first localisation technique considered is step testing. It is a technique in which the valves in an area are systematically closed, with the flow into the area constantly being monitored (Liemberger & Farley, 2004). This exercise is generally performed during minimum night flow. The test is able to give some indication as to where the leak is, but only coarsely and for large flows. Not all distribution networks were designed to enable step-testing, making it difficult to apply on any network. It is also a very laborious process and needs to be performed at night.

Acoustic logging is a method that places hydrophones or vibration sensors on accessible positions on the pipe, such as fire hydrants or valves (Hundaidi, et al., 2000). Recordings of the sensors are then taken during the night and analysed afterwards. Although the technique can cover large areas relatively quickly, its inability to detect small leakages in especially plastic piping makes it unsuitable for some conditions. With global trends moving to the use of plastic piping, leak detection in this type of pipes is crucial (Hundaidi, et al., 2000).

Ground penetrating radar analyses the soil directly beneath it by transmitting electromagnetic waves into the ground and measuring the reflections (Puust, et al., 2010). These reflections are analysed to create an image of the underground. The technique is not limited by the type of piping used and can scan an area relatively quickly. The main disadvantage of the radar is that anomalies in the ground, like metal objects, are detected and can lead to false conclusions. The depth at which the radar can scan can be a limiting factor depending on the standard depth at which the piping is laid.

Of the various pinpointing techniques, the leak noise correlator is one of the most common and effective tools in the industry, especially for metallic pipes (Puust, et al., 2010). The technique is similar to that of noise loggers since it also makes use of hydrophones or vibration sensors mounted on the pipe at accessible locations. The correlator records and compares the signals received from two sensors mounted along the pipe either side of a leak. The location of the leak can be pinpointed by comparing the time difference of arrival of the signals to the sensors. The technique is, however, not as effective on plastic pipes since the sound does not travel so easily, resulting in the sensors having to be placed closer to each other (Hundaidi, et al., 2000). The speed of sound traveling along the pipe is not always as predicted, resulting in the estimated location being inaccurate. The devices are also known to be expensive.

Trace gas injection testing is capable of detecting multiple leaks and works well even with junctions in the piping (Puust, et al., 2010). A traceable non-toxic, lighter than air gas mixture is injected under pressure into the piping. The gas escapes through the leak and rises to the surface where it can be detected by a portable gas analyser. Some leaks can, however, be missed if it is below the water level within the pipe and the gas cannot escape, or if the gas detector is not brought to within a meter of the leak. The technique is also notoriously expensive and becomes more expensive with increasing pipe size.

The pig-mounted acoustic sensing technique inserts a sensor into the piping while pressurised (Mergelas & Hendrich, 2005). The sensor then travels along the length of the pipe, listening for leaks. This is a difficult operation that is not always possible. The technique depends on the waterflow to carry the sensors downstream, requiring insertion to always be upstream, and also that there must be enough flow to carry the sensor. A modified version of the test exists where a pull cable is inserted to pull the sensor down the pipe. This enables the test to be performed when there is no flow. It is, however, a much more cumbersome procedure.

These existing detection techniques cannot characterise the leaks or accurately indicate the leak size. They are also generally expensive and require skilled operators.

There is thus room for a leak detection device and system that, at least to some extent, can detect small leakages; analyse a pipe network section at a time; is affordable; requires low skills to operate it; and exhibits low false detection rate for all pipe types.

The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.

SUMMARY OF THE INVENTION

In accordance with a first aspect of this invention there is provided a pipe condition assessment device for assessing the condition of an isolated section of a pipe network, the device comprising a mobile chassis supporting: either an on board source of water external to the isolated section or a connection to a source of water external to and separate from the isolated section, a pressure source in fluid communication with the on board source of water or said connection, a conduit in fluid communication with the pressure source and connectable to the isolated section, a flow meter in communication with the conduit and configured to sense flow rates and direction therein and to generate flow data embodying such information, a pressure sensor in communication with the conduit and configured to sense pressure therein and to generate pressure data embodying such information, a data storage means and/or a data transmitting means for storing and/or transmitting flow data and pressure data derived from the outputs of the flow meter and pressure sensor, respectively, and a controller having a computer program configured to control operation of the pressure source and to trigger recordal of flow data and pressure data at times co-ordinated with times of operation of the pressure source.

Further features of the invention provide for the device to include an adjustable venting valve capable of venting water out of the conduit at one or more venting pressures to provide for predetermined pressures within the conduit; for the venting valve to be a variable resistance valve, preferably an electrically controlled throttling valve; for the controller to be configured to trigger recordal of flow data and pressure data corresponding to flow and pressure in the conduit at each venting pressure; for the conduit to further comprise one or more inflow or outflow valves located between the venting valve and the external source of water; for the one or more inflow or outflow valves to be solenoid or manual valves; for the venting valve, flow meter, pressure sensor and inflow or outflow valves to be operable under the control of the controller; for the computer program to be configured to control operation of the pump and any associated valves such that flow and pressure data are recorded at a plurality of different pressures in the conduit; and for the pump to be a variable speed pump or a pump and throttling valve capable of pumping water from the external source of water through the conduit and into the isolated section at one or more applied pressures in accordance with instructions received from the controller.

Further features of the invention provide for a computer program product for assessing the condition of an isolated section of a pipe network to be embodied either in an on board computer program or in a remote computer in which instance the remote computer is programmed to receive flow and pressure data from a device as defined above wirelessly, by way of a hardwire, over an intranet, over the Internet or by transfer using a portable memory unit; in the alternative or in addition, for the computer program product to be in an on-board computer forming part of the controller of the device; for the computer program product to be configured to receive accumulated flow data and pressure data from at least one entire cycle of different pressures being applied to the conduit; for the computer program product to be configured to determine or predict one or more leakage characteristics (the sum of the head area slopes and initial leak areas) on the basis of data incorporating flow and pressure signals that are indicative of the condition of the isolated section.

Even further features of the invention provide for the computer program of the controller to comprise control logic configured to execute one or more of: an isolation test to determine whether a section of a pipe network is isolated; an isolation valve breach assessment to assess the characteristics of an isolation valve breach, a leakage test to determine whether the section contains one or more leaks, and/or a leakage assessment to assess the nature of one or more leaks in the section and /or one or more illegal connections by looking for their flow and pressure signals in the measurements.

Further features of the invention provide for the mobile chassis to be manually transportable or a trolley, trailer, or similar wheeled support in which instance the mobile chassis may be manually propelled; alternatively, for the mobile chassis to be towable in which instance it may have a hitching means for coupling to a tow bar of a towing vehicle.

Still further features provide for the external source of water to be a water tank having an outlet in fluid communication with the pump.

Yet further features of the invention provide for the conduit to comprise a connector for connecting to the isolated section; and for the connector to be connectable to a network access point, selected from a fire hydrant, scour valve, tap, access provided by removal of a pipe element such as an air valve, and a dedicated access point.

Further features of the invention provide for the flow meter to be arranged to provide flow data in the conduit at each applied pressure; for the flow data to include flow rate and flow direction data; for the flow meter to be configured to transmit the flow data to a remote receiver by way of the data transmitting means and/or to store the flow data on the data storage means; for the flow meter to be a bidirectional flow meter; and for the flow meter to be operable under the control of the controller.

Still further features of the invention provide for the pressure sensor to be arranged to provide data representative of pressure in the conduit at each applied pressure, for the pressure sensor to be positioned in the conduit proximate a connection to the isolated network; for the pressure sensor to be configured to transmit the pressure data to a remote receiver by way of the data transmitting means and/or to store the pressure data on the data storage means for subsequent downloading or transfer to a computer; and for the pressure sensor to be operable under the control of the controller.

Yet further features of the invention provide for the device to comprise a global positioning system (GPS) device configured to record GPS coordinates of an isolated section and to transmit the coordinates to a remote receiver and/or store the coordinates on the data storage means in association with data recorded in relation to a particular isolated section of a pipe network; and for the GPS device to be under the control of the controller.

In accordance with a second aspect of this invention there is provided a pipe condition assessment system for assessing the condition of an isolated section of a pipe network, the system comprising at least one pipe condition assessment device as defined above and a central processing station including a computer programmed to receive flow data and pressure data from the at least one pipe condition assessment device and to process it to provide a determination or prediction as to one or more leakage parameters.

Further features of the second aspect of the invention are as defined above for each of the pipe condition assessment devices and any on board or remote computer.

In accordance with a third aspect of this invention there is provided a method for assessing the condition of an isolated section of a pipe network, the method comprising: isolating a section of a pipe network from the rest of the pipe network, connecting a pump and an external source of water to the isolated section by way of a conduit, pumping water from the external source of water through the conduit and into the isolated section at one or more applied pressures under the control of a controller having a computer program in communication with the pump, measuring flow rates and pressures in the conduit at each applied pressure, and transmitting the measured flow rates and pressure to a remote receiver and/or storing the measured flow rates and pressures on a data storage means, and determining or predicting one or more leakage characteristics from the recorded flow data and pressure data in order to provide an assessment of the condition of the section, wherein the one or more leakage characteristics includes an identification of leak geometry.

Further features of the third aspect of the invention are as defined above for each of the pipe condition assessment devices and any remote or on board computer.

Still further features provide for the method to comprise a step of determining whether the section is isolated from the network, the step comprising: closing valves with the aim of isolating a section of a pipe network from the rest of the pipe network, opening a variable resistance valve to vent water from the isolated section to the atmosphere by way of a conduit, changing the resistance setting on the variable resistance valve to one or more settings under the control of a controller having a computer program in communication with the valve, measuring flow rates and pressures in the conduit at each valve setting, and transmitting the measured flow rates and pressure to a remote receiver and/or storing the measured flow rates and pressures on a data storage means, and determining or predicting the characteristics of the opening or openings in the valve or valves not isolating the section from the recorded flow data and pressure data.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Figure 1 is a schematic representation of one embodiment of a pipe condition assessment device according to the present invention;

Figure 2 is a block diagram representing components of a system of the present invention;

Figure 3 is a flow diagram representing a method of the present invention;

Figure 4 is a flow diagram representing steps of a method to determine whether a section is isolated;

Figure 5 is a flow diagram representing steps of a method to characterise a leakage in an isolation valve;

Figure 6 is a block diagram representing a computer program product of the present invention;

Figure 7 illustrates an example of a computing device in which various aspects of the invention may be implemented;

Figure 8 is a schematic representation of an example according to the present invention;

Figure 9 is a graph showing pressure and flow readings with time recorded during a leakage test;

Figure 10 is a plot of the pressure vs flow readings recorded during a leakage test; and

Figure 11 is a representation of some common pipe leak geometries in network pipes.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS A device (100) for assessing the condition of an isolated section (101) of a pipe network is provided. The isolated section may be a linear or a branched section which is typically isolated from the rest of the pipe network by closing isolation valves (103) at ends of the section.

As illustrated in Figure 1, one embodiment of the pipe condition assessment device (100) comprises a mobile chassis (102) supporting a source of water external to the isolated section that in this embodiment of the invention is in the form of a tank (104) and a pump (106) in fluid communication with the tank (104). A conduit (108) is in fluid communication with the pump (106) and is connectable to the isolated section. A flow meter (110) is in communication with the conduit (108) and is configured to record flow rates therein. A pressure sensor (112) is in communication with the conduit (108) and is configured to sense pressure therein. A data storage means (114) and/or a data transmitting means (116) is provided for storing and/or transmitting flow data and pressure data sensed by the flow meter (110) and pressure sensor (112), respectively. A controller (118) having a computer program is provided and configured to control operation of the pump (106).

The mobile chassis (102) may be a trolley, trailer, or similar wheeled support and may contain receiving formations into or onto which the components of the device (100) are received. The receiving formations may be provided by compartments, pockets or dividers, which may be padded to protect the components during transport. The mobile chassis (102) may be manually transportable or at least manually propelled. Alternatively, if it is sufficiently large or heavy, it may have a hitching means (120) for hitching to a vehicle so as to enable the mobile chassis (102) to be towed.

The external source of water (104) is in this embodiment provided by a water tank. The water tank may have an outlet (122) in fluid communication with the pump (106). Alternatively, the external source of water (104) may be provided by a connection to a section of the pipe network that is separate from the isolated section being tested or another external water source. The external connection may be accessed by a hose having a suitable fitting.

The pump (106) may be a variable speed pump or a pump and throttling valve capable of pumping water from the external source of water (104) through the conduit (108) and into the isolated section at one or more applied pressures and in accordance with instructions received from the controller (118). The controller (118) may comprise a computer program which is configured to be capable of switching the pump (106) on and off and preferably adjusting the pump speed.

The conduit (108) may comprise a connector (124) for connecting to the isolated section. The connector (124) may be connectable to a network access point, such as a fire hydrant (125), scour valve or similar dedicated access point, and may be provided by a Storz adaptor, an instantaneous adaptor, a Nakajima adaptor, or a threaded adaptor. As illustrated in Figure 1, the conduit (108) may include a side pipe (126) extending from the conduit (108) to the water tank (104) and pump (106). The side pipe (126) may include an inflow valve (128) and/or a nonreturn valve (130) and the conduit may contain an outflow valve (132) and/or a non-return valve (134). The outflow valve (132), inflow valve (128) and the non-return valves (130, 134) may be used to direct water flow through the conduit (108) and side pipe (126) in a selectable manner. For example, the inflow valve (128) may be closed and the outflow valve (132) opened when the pump (106) is pumping water from the water tank (104) into the section in order to prevent the water cycling through the conduit (108) and side pipe (126). Furthermore, the outflow valve (132) may be closed and the inflow valve (128) opened in order to facilitate filling the water tank (104) with water received from the network access point. The inflow (128) and outflow (132) valves may be electrically operated valves, such as solenoid valves, and may be opened and closed by the controller (118).

The flow meter (110) may be arranged to record flow data, including flow rate and flow direction, in the conduit (108) at each pressure applied by the pump (106). The flow meter (110) may be configured to transmit the flow data to a remote receiver (136) by way of the data transmitting means (116). Alternatively, or in addition, the flow data may be stored on the device (100) on the data storage means (114). The flow meter (110) may be a bidirectional flow meter or the flow meter (110) may be provided by two unidirectional flow meters arranged to record flow rates in the conduit (108) in opposite directions. The flow meter (110) may be operable under the control of the controller (118).

The pressure sensor (112) may be arranged to sense pressure in the conduit (108) at each pressure applied by the pump (106) and to output pressure data. The pressure sensor (112) may be positioned in the conduit (108) proximate the connector (124) in order to ensure that the pressure sensor (112) accurately senses the pressure of water entering or exiting the section from or to the conduit (108). The pressure sensor (112) may be configured to transmit the pressure data to a remote receiver (136) by way of the data transmitting means (116). Alternatively, or in addition, the pressure data may be stored on the device (100) on the data storage means (114). The pressure sensor (112) may be operable under the control of the controller (118). A data storage means (114) may be provided with the device (100) for storing recorded data. The data storage means (114) may comprise computer memory present in the device or may comprise access to a cloud database. A data transmitting means (116) may be provided for transmitting recorded data to the remote receiver (136). The data transmitting means (116) may comprise hardware and software suitable for transmitting data remotely, which may include a radio frequency transmitter, GSM or any other data transmitting means.

One or more leakage characteristics, used to indicate the condition of the isolated section, may be determined or estimated from data representing recorded flow data and pressure data.

Pipe distribution networks are typically grid-like and have a positive fluid pressure in the pipes that make up the network. If one of the isolation valves (103) used to isolate the section is faulty or not properly closed, fluid in the network will be forced into the section when a network access point is opened, such as when the section is connected to a conduit. It is therefore possible to determine whether the section is isolated from the rest of the network by measuring fluid flow out of the access point when the conduit is connected. If there is no flow or the flow is negligible, then the section can be regarded as isolated.

Venting of fluid out of the section and into the conduit (108) can be measured and the characteristics of the leakage in the isolation valve determined. In order to characterise such leakages, the device (100) may additionally comprise an adjustable venting valve (138) through which water in the conduit (108) may be vented at one or more venting pressures. The venting valve (138) may be a variable resistance valve, such as an electrically controlled throttling valve and may be controlled by the controller (118). The flow meter (110) and pressure sensor (112) may be configured to record flow and pressure data in the conduit (108) at each venting pressure. The flow and pressure data may be used to calculate one or more leakage characteristics which may be used to characterise a breach in an isolation valve (103).

The device (100) may comprise a global positioning system (GPS) receiver (140) configured to record GPS coordinates of each isolated section and transmit the coordinates to the remote receiver (136) and/or store the coordinates locally on the data storage means (114). The GPS coordinates may be associated with the flow and pressure signal data so as to enable a leak to be locatable once detected and characterised. The GPS receiver (140) may operate under the control of the controller (118).

The computer program of the controller (118) may comprise control logic that is configured to control operation of the pump and to trigger recordal of flow data and pressure data at times coordinated with times of operation of the pump. The control logic may furthermore be configured to execute one or more tests on the isolated section. The tests may include: an isolation test to determine whether the section is isolated, an isolation valve breach assessment to assess the characteristics of an isolation valve breach, a leakage test to determine whether the section contains a leak, and a leakage assessment to assess the characteristics of a leak in the section. Of course, in the event that there is more than one leak in the section, it will be characteristics of the sum of the leaks that is determined and it will not be known as to how many leaks there are. A graphic user interface (GUI) (142) may be provided with the device (100). The GUI (142) may be in communication with the controller (118) and one or more of the water tank (104), pump (106), flow meter (110), pressure sensor (112), data storage means (114) and data transmitting means (116). The GUI (142) may enable a user to operate the controller (118) and send instructions to the components of the device (100). The GUI (142) may also enable a user to view operating characteristics of the device (100) such as pump speed, venting pressure, fluid flow rate and direction, pressure, elapsed time and fluid level in the water tank (104). A power supply (144) for powering the electronic components of the device (100) may further be provided. The power supply (144) may be a generator, battery, or a connection to an electricity mains.

An air valve (146) may also be provided in the conduit to prevent air locks and enable the conduit (108) to be filled with water. A system (200) for assessing the condition of an isolated section (101) of pipe network is further provided. The system (200), as illustrated in Figure 2, comprises at least one pipe condition assessment device as described above and a central processing station (202) including a computer (204) programmed to receive flow data and pressure data from the at least one pipe condition assessment device. The system (200) may be configured to process the data to provide a determination or prediction as to one or more leakage characteristics. The central processing station (202) may be provided as an on board computer, alternatively or in addition, it may be provided by a remote computer. A method (300) for assessing the condition of an isolated section (101) of a pipe network is further provided. As illustrated in Figure 3, the method (300) comprises isolating (302) the section from the rest of the pipe network, connecting (304) a pump and an external source of water to the isolated section by way of a conduit, and pumping (306) water from the external source of water through the conduit and into the section at one or more applied pressure under the control of a controller. The controller has a computer program in communication with the pump which enables the pumping pressure to be adjusted (310). Flow rates and pressure in the conduit are measured (308) to generate flow and pressure data at each applied pressure, which is transmitted (312) to a remote receiver and/or stored on a data storage means. In order to assess the condition of the pipe, one or more leakage characteristics is determined or predicted (314) from the flow and pressure data. Based on the leakage exponent, a leak in the isolated section can be characterised (316).

The section may be isolated from the rest of the pipe network by closing isolation valves at ends of the section.

As illustrated in Figure 4, the method (300) may include a step of determining whether the section is isolated by opening (322) a venting valve in fluid communication with the conduit, allowing (324) water in the conduit to flow through the venting valve, measuring (326) flow rates in the conduit during venting, and comparing the flow rate to a threshold value in order to determine (328) whether the section is isolated. A flow rate that is greater than the threshold value may indicate that the section is not isolated, whereas a flow rate that is less than the threshold value may indicate that the section is isolated. The threshold value may be between 0.1 litres/minute and 10 litres/minute. Preferably the threshold value is between 1 litre/hour and 10 litres/hour. The step of determining whether the section is isolated may be carried out under the control of the controller.

As illustrated in Figure 5, the method (300) may include a step of identifying the characteristics of a breach in one or more isolation valve. The characteristics of the breach may be determined by opening (332) the venting valve, venting (334) water entering the conduit from the isolated section out through the venting valve at one or more venting pressure and measuring (336) flow rates and pressure in the conduit at each venting pressure. The venting pressure is adjusted (338) and the flow rate and pressure at each new venting pressure measured. The process is repeated until sufficient flow rate and pressure data has been measured. The data is transmitted (340) to a remote receiver and/or stored on a data storage means, and the data used to determine or predict (342) at least one leakage characteristic in order to characterise (344) the breach. The step of identifying one or more characteristics of a breach in one or more isolation valve may be carried out under the control of the controller.

The features of the components used in the method (300) are as defined above for each of the pipe condition assessment devices (100) and any remote or on board computer. A computer program product (400) for assessing the condition of the isolated section is illustrated in Figure 6 and comprises a computer-readable medium (402) having stored computer-readable program code (404) for performing the computer-implemented steps of the device (100), system (200) and method (300). The computer-readable medium may be a non-transitory computer-readable medium and the computer-readable program code may be executable by a processing circuit.

The computer program product (400) may be embodied either in an on board computer program or in a remote computer in which instance the remote computer is programmed to receive flow and pressure data from a device as defined above wirelessly, over an intranet, over the Internet or by transfer using a portable memory unit. In the alternative or in addition, the computer program product (400) may be in an on-board computer forming part of the controller of the device. The computer program product (400) may be configured to receive accumulated flow data and pressure data from at least one entire cycle of different pressures being applied to the conduit, and may be configured to determine or predict one or more leakage characteristics on the basis of data incorporating flow and pressure signals in which the leakage characteristics are indicative of the condition of the isolated section.

Figure 7 illustrates an example of a computing device (500) in which various aspects of the disclosure may be implemented. The computing device (500) may be suitable for storing and executing computer program code. The various participants and elements in the previously described system diagrams, for example the controller (118, 218), may use any suitable number of subsystems or components of the computing device (500) to facilitate the functions described herein. The computing device (500) may include subsystems or components interconnected via a communication infrastructure (505) (for example, a communications bus, a cross-over bar device, or a network). The computing device (500) may include one or more central processors (510) and at least one memory component in the form of computer-readable media. In some configurations, a number of processors may be provided and may be arranged to carry out calculations simultaneously. In some implementations, a number of computing devices (500) may be provided in a distributed, cluster or cloud-based computing configuration and may provide software units arranged to manage and/or process data on behalf of remote devices.

The memory components may include system memory (515), which may include read only memory (ROM) and random access memory (RAM). A basic input/output system (BIOS) may be stored in ROM. System software may be stored in the system memory (515) including operating system software. The memory components may also include secondary memory (520). The secondary memory (520) may include a fixed disk (521), such as a hard disk drive, and, optionally, one or more removable-storage interfaces (522) for removable-storage components (523). The removable-storage interfaces (522) may be in the form of removable-storage drives (for example, magnetic tape drives, optical disk drives, etc.) for corresponding removable storage-components (for example, a magnetic tape, an optical disk, etc.), which may be written to and read by the removable-storage drive. The removable-storage interfaces (522) may also be in the form of ports or sockets for interfacing with other forms of removable-storage components (523) such as a flash memory drive, external hard drive, or removable memory chip, etc.

The computing device (500) may include an external communications interface (530) for operation of the computing device (500) in a networked environment enabling transfer of data between multiple computing devices (500). Data transferred via the external communications interface (530) may be in the form of signals, which may be electronic, electromagnetic, optical, radio, or other types of signal. The external communications interface (530) may enable communication of data between the computing device (500) and other computing devices including servers and external storage facilities. Web services may be accessible by the computing device (500) via the communications interface (530). The external communications interface (530) may also enable other forms of communication to and from the computing device (500) including, voice communication, near field communication, radio frequency communications, such as Bluetooth™, etc.

The computer-readable media in the form of the various memory components may provide storage of computer-executable instructions, data structures, program modules, software units and other data. A computer program product may be provided by a computer-readable medium having stored computer-readable program code executable by the central processor (510). A computer program product may be provided by a non-transient computer-readable medium, or may be provided via a signal or other transient means via the communications interface (530).

Interconnection via the communication infrastructure (505) allows the central processor (510) to communicate with each subsystem or component and to control the execution of instructions from the memory components, as well as the exchange of information between subsystems or components. Peripherals (such as printers, scanners, cameras, or the like) and input/output (I/O) devices (such as a mouse, touchpad, keyboard, microphone, and the like) may couple to the computing device (500) either directly or via an I/O controller (535). These components may be connected to the computing device (500) by any number of means known in the art, such as a serial port. One or more monitors (545) may be coupled via a display or video adapter (540) to the computing device (500).

The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

Any of the steps, operations, components or processes described herein may be performed or implemented with one or more hardware or software units, alone or in combination with other devices. In one embodiment, a software unit is implemented with a computer program product comprising a non-transient computer-readable medium containing computer program code, which can be executed by a processor for performing any or all of the steps, operations, or processes described. Software units or functions described in this application may be implemented as computer program code using any suitable computer language such as, for example, Java™, C++, or Perl™ using, for example, conventional or object-oriented techniques. The computer program code may be stored as a series of instructions, or commands on a non-transitory computer-readable medium, such as a random access memory (RAM), a read-only memory (ROM), a magnetic medium such as a hard-drive, or an optical medium such as a CD-ROM. Any such computer-readable medium may also reside on or within a single computational apparatus, and may be present on or within different computational apparatuses within a system or network.

Flowchart illustrations and block diagrams of methods, systems, and computer program products according to embodiments are used herein. Each block of the flowchart illustration and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, may provide functions which may be implemented by computer readable program instructions. In some alternative implementations, the functions identified by the blocks may take place in a different order to that shown in the flowchart illustrations.

The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

The device (100), system (200), method (300) and computer program product (400) of the present disclosure may be used by municipalities or contractors to provide a service that will identify malfunctioning valves and leaks at a detailed level, identify the type of leaks likely present in the system and monitor the condition of the system over time. The system is capable of being operated by a low-skilled technician.

The invention will now be further described by way of the following non-limiting example.

In the example, a system of the present disclosure is used to assess the condition of an isolated section of a municipal pipe network. The system is contained in a stand-alone unit supported on a mobile chassis containing a water source (a water tank), a power source (generator or battery), a pressure source (a pump), a water meter (flow meter), valves, a pressure sensor and other components linked to a central processing and communication control component. A schematic representation of the system is provided in Figure 8. Further details of the components of the system are described in Table 1 below.

Table 1: Components of the example system

The system conducts tests and assessments to determine whether there are any leakages in the municipal pipe, and if so, what the nature of those leakages are. The test commences once the system is connected to a fire hydrant or network access point and the pipe section isolated. The pump pressurises the pipe section. The test then enters a loop and with each iteration of the loop the applied pressure is adjusted. After the pressure is adjusted, the system is given time to settle, before initiating the pressure and flow measurement. If there is no flow, or if all the iterations have been completed, the pump stops and the test is completed. Figure 9 shows a graph of the pressure and flow captured during a test in laboratory conditions. As seen on the time axis, the test can be completed within about 10 minutes. The underlying characteristics

being determined are based on the leak area - pressure graph onto which a linear function is fitted as shown in Figure 10. Using curve fitting, the parameters describing the leak can be determined from these data points.

Leakages may be characterised according to the N1 power equation given by: Q=c./7N1 Equation 1 in which N1 refers to the leakage exponent, Q the flow rate, h the pressure head, and c is a leakage coefficient.

The leakage coefficient provides a measure of the factors that influence the leak in a way that is unaffected by the flowrate. A typical leakage coefficient for a plastic pipe is about 0.6. N1 values range between 0.4 and 2.79. Generally, N1 values greater than 0.5 suggest an increase in leakage area with increase in pressure, whereas N1 values below 0.5 suggest a reduced area response to an increase in pressure. N1 values of 0.5 indicate a negligible leak area pressure response to pressure. Leak geometry, such as longitudinal, circumferential and spiral cracks, as well as pipe material influence the values of N1 obtained, as shown in Table 2 below.

Table 2: Summary of leakage exponents (N1) found for different leak types and materials

T uPVC = unplasticised polyvinyl chloride A leakage exponent of less than 0.5 indicates a circumferential crack, a leakage exponent of about 0.5 indicates a round hole or the presence of a faulty isolation valve, and a leakage exponent of greater than 0.6 indicates a longitudinal crack. A negligible or absent flow signal indicates an absence of leaks or faulty isolation valves in the section. Common pipe leak geometries are shown in Figure 11.

Water losses are commonly represented by the modified orifice equation. The modified orifice equation assumes that leakage area consists of two components, namely, i) fixed area (Ao); and ii) a variable leak area (Av). It accounts for the variation in area as a response to a change in

pressure. Assumptions of linear elastic or viscoelastic behaviour of pipe leaks allow for an equation linking area to pressure as follows: A = mh+A0 Equation 2

Where m = head area slope

Ao = initial area at 0 pressure h = pressure head

By combining Equations 1 and 2, the FAVAD equation can be represented as follows:

Equation 3

This equation can be used to determine different characteristics of pipe losses in a distribution network. By fitting a straight line to the area vs. pressure graph, both the effective initial area (Cd.A0) and effective head-area slope (Cd.m) are estimated.

Throughout the specification and claims unless the contents requires otherwise the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims (15)

CLAIMS:

1. A pipe condition assessment device for assessing the condition of an isolated section of a pipe network, the device comprising a mobile chassis supporting: either an on board source of water external to the isolated section or a connection to a source of water external to and separate from the isolated section, a pressure source in fluid communication with the on board source of water or said connection, a conduit in fluid communication with the pressure source and connectable to the isolated section, a flow meter in communication with the conduit and configured to sense flow rates and direction therein and to generate flow data embodying such information, a pressure sensor in communication with the conduit and configured to sense pressure therein and to generate pressure data embodying such information, a data storage means and/or a data transmitting means for storing and/or transmitting flow data and pressure data derived from the outputs of the flow meter and pressure sensor, respectively, and a controller having a computer program configured to control operation of the pressure source and to trigger recordal of flow data and pressure data at times co-ordinated with times of operation of the pressure source.

2. The device as claimed in claim 1, further comprising an adjustable venting valve capable of venting water out of the conduit at one or more venting pressures to provide for predetermined pressures within the conduit.

3. The device as claimed in claim 2, wherein the controller is configured to trigger recordal of flow data and pressure data corresponding to flow and pressure in the conduit at each venting pressure.

4. The device as claimed in claim 2 or claim 3, wherein the conduit further comprises one or more inflow or outflow valves located between the venting valve and the external source of water.

5. The device as claimed in claim 4, wherein the venting valve, flow meter, pressure sensor and inflow or outflow valves are operable under the control of the controller.

6. The device as claimed in any one of claims 1 to 5, wherein the pressure source is a variable speed pump or a pump and throttling valve capable of pumping water from the external source of water through the conduit and into the isolated section at one or more applied pressures in accordance with instructions received from the controller

7. The device as claimed in any one of claims 1 to 6, wherein a computer program product for assessing the condition of the isolated section is embodied either in an on board computer program or in a remote computer.

8. The device as claimed in claim 7, wherein the remote computer is programmed to receive flow data and pressure data from the device wirelessly, by way of a hardwire, over an intranet, over the Internet or by transfer using a portable memory unit.

9. The device as claimed in claim 7 or claim 8, wherein the computer program product is configured to receive accumulated flow data and pressure data from at least one entire cycle of different pressures being applied to the conduit.

10. The device as claimed in any one of claims 7 to 9, wherein the computer program product is configured to determine or predict one or more leakage characteristics on the basis of data incorporating flow and pressure signals to indicate the condition of the isolated section.

11. The device as claimed in any one of claims 1 to 10, wherein the computer program of the controller comprises control logic configured to execute one or more of: an isolation test to determine whether a section of a pipe network is isolated; an isolation valve breach assessment to assess the characteristics of an isolation valve breach, a leakage test to determine whether the section contains one or more leaks, and/or a leakage assessment to assess the nature of one or more leaks in the section.

12. The device as claimed in any one of claims 1 to 11 further comprising a global positioning system (GPS) device configured to record GPS coordinates of the isolated section and to transmit the coordinates to a remote receiver and/or store the coordinates on the data storage means in association with data recorded in relation to a particular isolated section of a pipe network.

13. A pipe condition assessment system for assessing the condition of an isolated section of a pipe network, the system comprising at least one pipe condition assessment device as claimed in any one of claims 1 to 12, and a central processing station including a computer programmed to receive flow data and pressure data from the at least one pipe condition assessment device and to process the flow and pressure data to provide a determination or prediction as to one or more leakage characteristics.

14. A method for assessing the condition of an isolated section of a pipe network, the method comprising: isolating a section of a pipe network from the rest of the pipe network, connecting a pump and an external source of water to the isolated section by way of a conduit, pumping water from the external source of water through the conduit and into the isolated section at one or more applied pressures under the control of a controller having a computer program in communication with the pump, measuring flow rates and pressures in the conduit at each applied pressure, and transmitting the measured flow rates and pressure to a remote receiver and/or storing the measured flow rates and pressures on a data storage means, and determining or predicting one or more leakage characteristics from the recorded flow data and pressure data in order to provide an assessment of the condition of the section, wherein the one or more leakage characteristics includes an identification of leak geometry.

15. A method as claimed in claim 14, further comprising a step of determining whether the section is isolated from the network, the step comprising: closing valves with the aim of isolating a section of a pipe network from the rest of the pipe network, opening a variable resistance valve to vent water from the isolated section to the atmosphere by way of a conduit, changing the resistance setting on the variable resistance valve to one or more settings under the control of a controller having a computer program in communication with the valve, measuring flow rates and pressures in the conduit at each valve setting, and transmitting the measured flow rates and pressure to a remote receiver and/or storing the measured flow rates and pressures on a data storage means, and determining or predicting the characteristics of the opening or openings in the valve or valves not isolating the section from the recorded flow data and pressure data.