System for detecting gas leaks

Abstract

A system for detecting gas leaks comprises: a gas sensor probe, and a tracking system 2; wherein the tracking system comprises at least one tracking device configured to determine a location of the ga

Description

Field of Invention The present invention relates to the field of gas leak detection. More specifically, the invention relates to a system for detecting gas leaks using a gas sensor probe and a tracking system. Background In a variety of industries and settings it is required to test for leak tightness. This is particularly true when assembling devices which produce, or rely upon, gases. These can use a variety of sensors such as but not limited to electrochemical gas sensors, catalytic bead sensors, infrared gas sensors and photoionization gas sensors. Independent of the type of sensor, these are often deployed in the form of a handheld device using a single sensor. Whilst this allows for the detection of a gas, it is required for the user to manipulate the sensor to all potential leak points to find whether a leak is present, commonly referred to as “sniffing”. The user must be thorough in checking each possible source for a leak in order to be confident that no potential leak is overlooked. This operator dependency is often cited as the main disadvantage of the “sniffing” method. Human error means that an unacceptable margin of error may persist. The need for detecting gas leaks is present in many industrial applications. When applied to hydrogen it includes electrolysis (such as detecting leaks from electrolysers), fuel cells and use cases such as the assembly and maintenance of systems such as those used in aerospace, automotive and more. The sniffing methodology has a unique importance in leak testing, because it is one of the few methods that is able to localise where a leak is occurring, particularly useful in a manufacturing environment, where a high level of resolution and accuracy is required. Other commonly used methodologies in manufacturing are the accumulation or vacuum chamber method. These are excellent at determining whether a leak exists, but do not provide the location of the leak. In the manufacturing of high value, complex and safety critical systems, sniffing must be employed for the purpose of locating a leak. This allows the possibility of repair / rework, reducing waste, and / or a better understanding of production failure modes leading to continuous design and manufacturing improvements. The process of sniffing is sometimes automated using robotics, particularly in mass production of high value systems such as car engines and air conditioning systems. Tooling costs and setup time are very high, with limited system flexibility. The approach presented removes or reduces operator dependency, while maintaining the flexible and relatively low setup costs associated with manual sniffing systems. The object of the present disclosure seeks to at least partly ameliorate the above problems. Summary of the Invention Aspects and embodiments of the present invention are set out in the appended claims. These and other aspects and embodiments of the invention are also described herein. According to one aspect of the disclosure there is provided a system for detecting gas leaks comprising: a gas sensor probe; and a tracking system; wherein the tracking system comprises at least one tracking device configured to determine a location of the gas sensor probe; and wherein the gas sensor probe is configured to detect a gas at the determined location. The gas sensor probe may be a mobile probe, in particular a handheld probe, such as a user can move freely around a device being leak tested. The gas sensor probe may comprise a handle portion (by which an operator holds the probe) and a sensor portion comprising a gas sensor for detecting a gas. The tracking system for determining a location of the gas sensor probe gives rise to a number of advantages. Firstly, the tracking system can be used to track previous locations of the gas sensor probe, so as to provide information relating to which parts of the device being leak tested have been probe. This enables more thorough testing of the device, by ensuring all areas of the device are tested. Second, the tracking system can be used to record the locations at which a gas is detected so as to provide information relating to which parts of the device require repair or replacement to stop the leaks. This enables more reliable testing of a device by reducing reliance on an operator’s reading of a gas sensor output. Third, the tracking system can be used to enable more efficient testing of a device, for example: the tracking system can be used to ensure that known typical potential leak locations on a particular type of device are probed; the tracking system can used to mark locations where an operator manually detects potential leaks; and the tracking system can be used to infer a likely leak location from the readings of gas detected at other locations. Preferably, the at least one tracking device comprises a tracking device coupled to the gas sensor probe. For example, the at least one tracking device may be mounted to the exterior of the probe. Alternatively, the tracking device may be integrated internally within the probe. In particular, the tracking device may be mounted at or near the sensor portion of the gas sensor probe. Advantageously, the at least one tracking device may allow the tracking system to determine the location of the gas sensor probe. Further, containing all components of the system within or attached to the gas sensor probe may advantageously increase the portability of the system. Preferably, the at least one tracking device comprises multiple tracking devices coupled to the gas sensor probe. For example, the tracking device may include multiple tracking devices mounted to the exterior of the gas sensor probe, or multiple tracking devices integrated within the probe. In either case, the multiple tracking devices may be configured in a distributed arrangement (for example, in linear alignment, or in a triangular or square arrangement) such as might enable the location of the probe comprising the tracking devices to be determined based on a triangulation of the multiple tracking devices. This may also allow the tracking system to maintain a more consistent connection with the tracking devices and hence obtain a more accurate determination of the location of the gas sensor probe. Preferably, the system further comprises at least one structure separate from the gas sensor probe, wherein the at least one tracking device comprises a tracking device coupled to the structure. This may be in addition to, or as an alternative to, the tracking device coupled to the probe. The structure may surround a space or volume within which a device to be leak tested is placed. The structure may be stationary, such that movement of the gas sensor probe relative to the structure is used to determine the location of the gas sensor probe using the tracking devices of the tracking system. Advantageously, mounting a tracking sensor to a separate structure may allow a wider variety of gas sensor probes to be used. Preferably, the at least one tracking device comprises multiple tracking devices coupled to the at least one structure. For example, there may be a tracking device fitted at each side or vertex of the structure. Advantageously this may allow the tracking devices to sense a larger region within which a device to be leak tested can be placed. Preferably, the at least one structure comprises at least one stand, at least one frame, or a housing, separate from the gas sensor probe. The stand, frame or housing may surround a volume in which a device to be leak tested is placed. Advantageously, this may allow the system to be portable, and hence facilitates use of the system in remote locations or when a device to be leak tested must be tested in situ. Preferably, the tracking system is configured to determine the location of the gas sensor probe based at least in part on an interaction between the at least one tracking device coupled to the gas probe and the at least one tracking device coupled to the structure. For example, the tracking device coupled to the gas probe and the tracking device couple to the structure may form a pair, and an interaction between the pair may be used to determine the location of the gas sensor probe. Preferably, the at least one tracking device coupled to the gas sensor probe and the at least one tracking device coupled to the structure may form constituent parts of a single tracking device such that the parts of the pair are arranged to communicate via a wireless or wired connection. For example, the tracking device coupled to the gas probe and the tracking device couple to the structure may form a transmitter and receiver pair (or vice versa). Advantageously this may increase the accuracy of the determination of the location of the gas sensor probe and hence allow a more precise determination of the potential locations of a leak. Preferably, the system further comprises a computing device configured to receive data from the gas sensor probe and from the tracking system. Preferably, the computing device is configured to associate the data received from the gas sensor probe with the data received from the tracking system. Advantageously this may allow the system to identify locations where a gas is detected. Preferably, the computing device is configured to associate the data received from the gas sensor probe with the data received from the tracking system based on the time at which the location of the gas sensor probe is determined and the time at which the gas is detected at the determined location. For example, data received from the gas sensor probe and data received from the tracking system at the same time may be associated together. Advantageously this may also allow data to be prioritised based on the time, wherein more recent data may be given more importance than data recorded previously, for example more recent gas detection data may overwrite older gas detection data for the same location. Furthermore, a user may be able to determine the duration of time since a device to be leak tested was previously tested and hence the user may be able to prioritise which devices require more urgent testing and / or schedule devices for testing according to their duration of time since a previous test. Preferably, the data received from the gas sensor probe comprises data relating to a concentration of the detected gas measured by the gas sensor probe. This may allow the system to determine locations of higher gas concentration relative to other locations where a gas concentration is detected. Advantageously this may allow the system to sort and display the data according to a priority of importance. Preferably, the computing device is configured to compare the measured concentration to a threshold concentration. This may allow the system to identify locations where the concentration of a gas exceeds the threshold, and mark such locations as potential gas leak locations. Advantageously, the system may alert the user when a gas concentration exceeds a dangerous threshold concentration level and thus advantageously reduce the chance of human error causing a dangerous leak not to be detected. Preferably, the computing device is configured to infer, based at least in part on the data relating to the concentration of the detected gas at one or more locations, the location of at least one potential gas leak. For example, if the gas concentration measurements are increasing as the probe moves in a particular direction, the computing device may infer that a leak is located further in that direction. The distance to the leak in that direction may be inferred from the change in the gas concentration recorded as a function of distance along the direction. Similarly, if the gas concentration measurements are consistently high around the perimeter of a region, the computing device may infer that a leak is located towards the centre of that region. Advantageously this may mean the user is not required to move the gas sensor probe to every possible location and may instead selectively sample the space around a device to be leak tested and thus reduce the amount of time needed to detect a gas leak. This may also mean that a user can be directed to probe inferred potential leak locations. Preferably, the computing device is configured to generate a heatmap indicating the concentration of the gas detected at one or more locations. Advantageously this may allow a user to more quickly identify visually locations of relatively higher gas concentration in relation to other locations, or locations not yet tested, and hence focus the selective sampling of locations to more important areas of the device to be leak tested. Preferably, the computing device is configurated to indicate on the heatmap locations at which the measured concentration of the gas exceeds the threshold concentration. Preferably, the computing device is configurated to indicate on the heatmap the inferred location of the at least one potential gas leak. Preferably, the computing device is configured to generate a tracking map indicating regions that have been probed by the gas sensor probe and / or regions that have not been probed by the gas sensor probe. Advantageously this may allow the user to prevent duplication of work by reducing the chance an area of the device to be leak tested is accidentally checked multiple times, or to reduce the chance that an area of the device to be leak tested is not probed. Preferably, the computing device is configured to indicate on the tracking map regions containing a potential gas leak, preferably wherein the regions containing a potential gas leak are inferred from the data received from the gas sensor probe and / or the data received from the tracking system and / or from information relating to a device being tested by the system for gas leaks. Advantageously this may allow a user to test a device for gas leaks more effectively by concentrating their probing on areas of the device that the data suggests are more likely to include gas leaks. Preferably, the system further comprises a user interface to enable a user to input a location of a potential gas leak. Advantageously this may allow the system to incorporate any preexisting knowledge about the device to be leak tested such as locations at which the device has previously leaked and thus that are relatively more important to check than others. Preferably, the computing device is configured to indicate on the tracking map the user input location of the potential gas leak. A user may then review the tracking map to see whether or not the marked location has been sufficiently probed to obtain gas detection data. Preferably, the system is configured to: remove the indication of the user input location of the potential gas leak from the tracking map upon determining that the user input location of the potential gas leak has been probed by the gas sensor probe; and / or issue an alert to a user upon determining that the location of the potential gas leak has not been probed by the gas sensor probe. In this way, the user can see visually whether potential leak locations have been probed or whether they still need to be probed. Preferably, the system further comprises a display configured to display the heatmap or the tracking map to a user. This may allow the user to react in real time to the data recorded by the system and hence make adjustments to the locations at which they move the gas sensor probe. Advantageously, this may improve the overall efficiency of the system by allowing a user to increase the speed at which they detect leaks. Preferably, the display is configured to display a visual indicator in relation to the heatmap or tracking map to guide the user to probe a particular location. For example, the display may include an arrow indicating to the user where to move the gas sensor probe to probe areas having potential gas leaks. Preferably, the display is configured to display a visual depiction of a device being tested by the system for gas leaks. For example, if an electrolyser is being tested for leaks, the display may include a visual depiction of the electrolyser. The depiction may be a computed aided design (CAD) model of the electrolyser. For example, the depiction may be generated following a user selection of the type, make or model of the device being tested. This enables a user to see how the location of the detected leaks correspond to the components of the device being tested. Preferably, the display is configured to display an indication of the determined location of the gas sensor probe in relation to the visually depicted device. Advantageously, this may allow the user to more easily identify the locations displayed in the heatmap and hence more quickly detect leaks. According to another aspect described herein, there is provided a means for detecting gas leaks comprising: • A pre-determined testing volume with X, Y, Z dimensions with a device to be leak checked placed in said pre-determined testing volume, • A gas sensor probe, the gas sensor probe comprising one or more tracking means (e.g., a tracking device as described above), • A tracking system, the tracking system comprising one or more sensor(s) (e.g., a further tracking device as described above) for tracking the one or more tracking means on the gas sensor in the testing volume, • A display unit adapted to display the pre-determined testing volume with information gathered by the gas sensor probe and tracking system It is envisaged that the present disclosure may be used to detect gas leaks using test fluids such as hydrogen, helium, tracer gas or forming gas in Electrolysers, Fuel Cells, Valves, Refrigeration Systems, Automotive, Aerospace systems. The present disclosure provides a significant benefit to reducing, or removing, the human error of the “sniffing” methodology, while maintaining its’ flexibility in lower volume manufacturing. Whilst it is envisaged that the pre-determined volume may be in a variety of settings such as in a manufacturing setting or on site, regardless of use case the boundaries of said volume shall be defined prior to use. Furthermore, it is envisaged that the one or more sensor(s) of the tracking means will be situated to ensure a substantial amount of entire testing volume is covered, possibly by using the boundary of the pre-determined volume. Examples of devices to be leak tested during manufacturing and in use include electrolysers, fuel cells, storage tanks and more. Such devices may be tested during commissioning or maintenance. Preferably, the one or more tracking means is envisaged as tracking nodes placed upon the gas sensor probe, and more preferably still calibrated with the tracking system, prior to use. In a preferred embodiment the device is secured in place in the testing volume by fastening means, more preferably still in a known / pre-determined location in the test volume. Optionally means may be provided to alert the user if the device to be tested is moved from its original position. Whilst it is envisaged that any sensor type capable of tracking a tracking node may be used, in a preferred embodiment the sensors will be any one or combination of: optical, infrared, or other suitable alternatives. In any scenario, the tracking node and tracking system sensor(s) must be complimentary. In a preferred embodiment of the present disclosure, means for communicating measured data as described herein (any combination of: gas levels, location and time) to a computing means shall be provided, this may be wired or wireless. In a preferred embodiment of the present disclosure means for communicating the spatial location measured by the one or more sensor(s) of the one or more tracking node(s) to the computing means is provided to allow combination of the measured gas levels, temporal, and the spatial data. In an embodiment of the present disclosure, a CAD or similar model may be provided to the computing means and integrated with X, Y, Z coordinates of the pre-determined area. In a further preferred embodiment of the present disclosure the model of the device to be leak tested is incorporated into the display. More preferably still the display will allow for manipulation of the map such that it is 3D so all aspects may be checked both in real time and analysed after. It is envisaged that a variety of units may be used by the gas sensor probe, depending upon the gas to be monitored such as PPM, a traffic light system or other alternative. In some embodiments a leak rate may be used such as mbar.L / s when a pump is used to pull a certain flow rate of gas over the sensor of the gas sensor probe. In a preferred embodiment of the present disclosure a gradient scale akin to a heat map from the measured data may be displayed to allow a visual representation of low to high concentration on an absolute, or relative basis. This information may be combined with the spatial data to allow the generation of a heat map showing for all measured areas measured gas levels high to low. The values displayed may be updated in real time so as to be accurate as possible. In an alternate view, the display may show only where the tracker has been to allow a user to check and determine whether all possible leak point have been checked. Preferably, the model is adapted to mark potential leak points on the display so the user can identify whether they have checked each point. More preferably still, the computing means is adapted to prompt the user visually, audibly or otherwise if a potential leak point has not been checked. In an alternative embodiment of the present disclosure the system is adapted to have a checklist on the display which automatically remove potential leak points as they are checked, or prevent the test from being deemed completed unless all locations have been checked at least once. In an embodiment of the present disclosure means are provided such as a button on the gas sensor probe, to mark a suspected leak, the computing means marking this on the model. Alternatively leak points can be marked after the sensor has been used by a computing means connected to the tracking system. Preferably the system automatically marks a leak, this may be if the probe detects gas levels above a pre-determined threshold, or other suitable trigger. Whilst the present disclosure is not intended to be limited by the location of the display, it is envisaged that the display will be on a screen visible to an operator while in use. In a further preferred embodiment means will be provided to allow the display to switch between different modes while still in use such as a button mounted on the gas sensor probe, or a separate remote control device. Preferably all tracking and marking of models is saved to allow for future reference. It is envisaged that marked leaks for each device of each device type leak tested can be automatically compiled to allow for analysis of failure rates of each potential leak allowing design and or manufacturing improvements to be made. The data to be displayed is envisaged to be the coordinates of the gas sensor probe with at least one or both of the measured gas, in PPM, leak rate or similar, and the time of sensing. In a preferred embodiment of the present disclosure the display unit is adapted to show three types of data: visible, sight plus shroud, and unexplored. Visible is where the sniffer is at that moment in time, and shows live data. Sight plus shroud shows data which was correct when “visible” but is not current as the sniffer has moved, such information may be shaded. Unexplored shows no tracking information or other data as the probe has not yet been there. The approach may be considered akin to the map view in computer games such as Age of Empires II™. Generic data which may be collected by the system of the present disclosure described herein is outlined below in Table 1: Time (T) X Coordinate Y Coordinate Z Coordinate Leak ti Xi yi Zi qi t2 x2 y2 Z2 q2 t3 X3 ya Z3 qs t4 X4 y4 Z4 q4 ts X5 ys z5 qs te Xe y@ z6 qe Table 1 At time T the X, Y, Z coordinates of the gas sensor probe within the pre-determined testing volume is recorded and matched with the measured leak data. The measured leak data may be a gas level or concentration at the coordinates, or a binary output depending on whether or not a gas is detected to be present (e.g., because a detected gas level or concentration exceeds a threshold). Whilst it is preferable for continuous measurements to be taken, it is envisaged that measurements may be taken at pre-determined intervals. Indeed, it is possible that no time measurement may be recorded, although preferable as it allows for the comparison of a before and after if the same spot is checked twice, in the event an in situ repair is undertaken. According to the present disclosure there is provided a method for detecting gas leaks utilising a device as described above comprising the following steps: • Defining a pre-determined area with X, Y, Z coordinates • Placing a device to be leak checked within said pre-determined area, • Tracking the movement of a trackable gas sensor probe within the pre-determined area, • Displaying on a display the tracked information. According to another aspect of the disclosure there is provided a method for detecting gas leaks comprising: providing a gas sensor probe and a tracking system, wherein the tracking system comprises at least one tracking device, using the at least one tracking device to determine a location of the gas sensor probe; and using the gas sensor probe to detect a gas at the determined location. The methods may comprise additional steps related to incorporating any of the above described variants. It is envisaged that the pre-determined area may be fixed in a manufacturing / testing setting. Alternatively, the pre-determined area may be in the field such as for a deployed electrolyser to be checked during maintenance. A user may be either a person, or a robotic arm with computing means adapted to incorporate measured information, or pre-defined movement paths. The user may be able to toggle between display modes to view a “heat map” of detected gas, or simply where the gas sensor probe has been within the pre-determined area. The user may also be able to mark where a possible leak is detected by marking a point on the display model suitable for information when fixing the leak and for analysis of where leaks are occurring. Preferably the system is adapted to automatically mark such leaks if a predetermined threshold of detected gas is sensed. It is envisaged that each device may be tested without any storage of information. Preferably, each device would have a serial number or equivalent to be paired with the leak testing information to allow for traceability though the re-work / maintenance process. Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure. Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and / or all features in one aspect can be applied to any, some and / or all features in any other aspect, in any appropriate combination. It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and / or supplied and / or used independently. As used herein, the term “gas” is used to refer to any gas, vapour, or particulate which may be measured by a probe or sensor, such as but not necessarily limited to hydrogen. As used herein, “gas sensor probe” is used to refer to any sensor, probe or other measurement device capable of determining the concentration or presence of a gas or equivalent. Such probes may be any suitable probe. As used herein the term “pre-determined testing area” and “pre-determined testing volume” may be used interchangeably. As used herein references to a "device” to be leak tested are used to refer to either a single component or an overall system to be leak tested by the system disclosed herein. The invention also provides a computer program or a computer program product for carrying out any of the methods described herein, and / or for embodying any of the apparatus features described herein, and a computer readable medium having stored thereon a program for carrying out any of the methods described herein and / or for embodying any of the apparatus features described herein. The invention also provides a signal embodying a computer program or a computer program product for carrying out any of the methods described herein, and / or for embodying any of the apparatus features described herein, a method of transmitting such a signal, and a computer product having an operating system which supports a computer program for carrying out the methods described herein and / or for embodying any of the apparatus features described herein. Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory. Furthermore, features implanted in hardware may generally be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly. The invention extends to methods, system and apparatus substantially as herein described and / or as illustrated with reference to the accompanying figures. One or more aspects will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which: Brief description of the figures To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 shows a gas sensor probe with tracking devices; Figure 2 shows a pre-defined testing volume with tracking devices; Figure 3 shows a user with the gas sensor probe and display unit; Figure 4 shows a sample tracking map; Figure 5 shows a sample tracking map with markers for possible leak points; Figure 6 shows a sample heat map; and Figure 7 shows a sample heat map with markers for leak points. Detailed description Figure 1 shows a schematic of a gas sensor probe 1 for the system of the present disclosure. The gas sensor probe 1 comprises a gas sensor configured to detect the presence of a gas. In this example, the gas sensor is also configured to measure a concentration of the gas. The gas sensor probe 1 also comprises a plurality of tracking devices 2 coupled to the gas sensor probe 1. In this example, there are four tracking devices 2 coupled to the gas sensor probe 1, specifically coupled to the exterior of the probe proximate the edges of the gas sensor probe 1. In other examples, there may only be a single tracking device. In other example, the tracking device(s) may be integrated within the probe 1 rather than attached to the exterior. The plurality of tracking devices form at least part of a tracking system wherein the tracking sensors are used to identify a location of the gas sensor probe. In the embodiment shown in Figure 1, the gas sensor probe 1 is provided as a wireless device configured to communicate data measured by the gas sensor wirelessly. For example, the gas sensor probe 1 may be connected wireless to a computing device and configured to transmit to the computing device data measured by the gas sensor. In an alternative embodiment the gas sensor probe 1 may further comprise a wired connection to the computing device for transmitting the data. The data may also include data relating to the location of the gas sensor probe 1 as determined using the tracking devices 2. Figure 2 shows a schematic of the system for detecting gas leaks comprising the gas sensor probe 1 shown in Figure 1 being used by an operator to test for gas leaks from a device 10. The device to be leak tested 10 is on a stand 11 located within a structure 12, of a substantially cuboid shape in this example, defining a testing volume within the structure. At the vertices of the structure 12 are a plurality of tracking devices 3 separate from the tracking devices 2 that are coupled to the gas sensor probe 1. Within the structure 12 stands a user 30 holding a gas sensor probe 1. In the example of Figure 2, the structure 12 is a metal frame of a substantially cuboid shape. The plurality of external tracking devices 3 in this example are removably attachable to the structure 12 at the vertices of the cuboid such that the plurality of external tracking devices 3 may be attached at any combination of vertices or other parts of the structure 12. It will be appreciated that the specific configuration of tracking devices is dependent on the type of the plurality of external tracking devices 12 used and the form of the device to be leak tested. For example, the plurality of external tracking devices 3 may be provided along one or more edges of the structure 12 instead of at the vertices. In an alternative example, the structure 12 may instead be formed of a set of freestanding upright stands wherein the plurality of external tracking devices 3 may be removably attachable to the stand, which may be varied by the user 30 as required by the situation. The stand may be placed at non-orthogonal arrangements and / or the structure may form an irregular shape. In a further alternative, the structure may not be freestanding and instead edges of the structure 12 may form one or more walls of a room or container. In this embodiment, the plurality of external tracking devices 3 may be attached to the one or more walls or vertices of the room or container. In Figure 2, the device to be leak tested 10 is placed entirely within the boundary of the structure and is placed upon a stand 11. The stand is not a required part of the system and is optionally provided for the benefit of a user 30 to facilitate easier access to the device to be leak tested 10 and to facilitate consistent positioning of the device in the system. The system may be provided without the stand. The use of a stand 11 may depend on the size of the device to be leak tested 10 wherein larger devices may not be able to be placed on the stand 11. In some embodiments the stand 11 comprises means to fasten the device to be leak tested 10 to the stand 11 to prevent movement of the device relevant to the structure 12. In some situations, the device to be leak tested 10 will not be fully contained within the structure. For example, when the device is a pipeline. In these situations, the system may be used to test for leaks along a portion of the pipeline, wherein that structure is arranged around that portion of the pipeline, and then moved to another portion of the pipeline and the process repeated until all regions of the pipeline to be leak tested 10 have been tested. The user 30 of Figure 2 is a human but it will be understood that the gas sensor probe 1 may be attached or held to any number of robotic or autonomous devices suitable for manipulating the gas sensor probe 1 to multiple locations adjacent the device to be leak tested 10. Figure 3 shows a schematic of the system of Figure 2, further comprising a display 20. Figure 3 again depicts a device 10 to be leak tested resting on a stand 11 located within a structure 12, wherein a plurality of external tracking devices 3 are provided at the vertices, as in Figure 2. Figure 3 also shows a user 30 holding the gas sensor probe 1 comprising a plurality of tracking devices 2 as in Figure 1. The user 30 may move the gas sensor probe 1 around the device to be leak tested 10 and stand 11 within the structure 12. The plurality of external tracking devices 3 are placed, or of a type, to ensure that freedom of movement is possible by the gas probe sensor 1 held by the user 30. In this example, as in Figure 2, the tracking system comprises both at least one tracking device 2 coupled to the gas sensor probe 1 and at least one external tracking device 3 separate from the gas sensor probe 1. The tracking devices 2, 3 cooperate to determine the location of the gas sensor probe 1. In this way, the tracking system is configured to determine the location of the gas sensor probe based at least in part on an interaction between the at least one tracking device 2 coupled to the gas sensor probe and the at least one tracking device 3 coupled to the structure 12. Also visible in Figure 3 is the optional additional feature of a display 20. The display 20 may depict information relevant to the detecting of gas leaks as will be discussed further below in reference to Figure 4-7. In the embodiment of Figure 3 the display 20 depicts a model of the device 21 to be leak tested and the stand 11. Not shown in Figure 3 are additional computing means to control the display, based on data received at the computing device from the tracking devices 2, 3, or the means to switch between views as shown in Figures 4 - 7. In Figure 3, the display 20 is depicted as a standalone unit located outside the structure 12. However, it will be appreciated that the display 20 may be provided in a multitude of ways depending on the specific requirements of the user. Possible alternative embodiments of the display include, but are not limited to: a standalone unit located within or attached to the structure 12, a screen provided at or on the gas sensor probe 1 (such that it may be visible to the user 30 holding the gas sensor probe 1) or the information may be provided to a device equipped with a screen such as a computer or laptop for viewing by the user 30 on the screen of said computer or laptop. In an alternative embodiment (not shown), the display is provided as part of an augmented reality (AR) headset. The AR headset may be removably coupled to a tracking system of the present disclosure and / or a computing means and / or wearable by the user. The AR headset may display an augmented view of the device being leak tested. The augmented view may comprise any / all of: a heat map, indicators of possible leak points or a indication of previously probed locations. Advantageously, this may allow a user to leak test a system remotely and / or may allow the user to detect leaks more efficiently. While the types of the tracking devices 2, 3 are not essential to the invention, a variety of examples are envisioned. In one example, the tracking device(s) 3 mounted on the structure 12 may comprise a camera configured to use computer vision to determine the location of the gas sensor probe 1, in which case no tracking devices 2 are required on the probe 1. In another example, the tracking device(s) 2 coupled to the probe may comprise a camera configured to use computer vision to determine the location of the gas sensor probe 1. In another example, the tracking devices 2, 3 may include a transmitter and receiver; for example the external tracking devices 3 may comprise an infrared (or other electromagnetic radiation) transmitter and the tracking devices 2 on the gas probe 1 may comprise an infrared receiver (or vice versa), such that the position of the gas probe 1 can be determined based on the strength of the infrared received at the receiver from the transmitter. In yet another example, the tracking devices 2, 3 may include a reader and a passive tag; for example the external tracking devices 3 may comprise an radio frequency identification (RFID) reader and the tracking devices 2 on the gas probe 1 may comprise an RFID tag such that the position of the gas probe 1 can be determined based on the strength or the RFID signal between the reader and the tag. Figures 4 to 7 depict different possible views that the display 20 of Figure 3 may be configured to generate. Preferably, the user 30 may be able to select which view to generate on the display 20 via an input such as a button connected to the display 20 (not shown). The user’s selection of which view to generate may be based at least in part on the information associated in each view as will be described below. Preferably the generation of each possible view is based at least in part on data received from one or both of the plurality of tracking devices 2, 3. Figure 4 shows a sample (2D) tracking map 20a on the display 20 comprising a shaded region 21a and a depiction of the device to be leak tested 21. The shaded region 21a indicates locations that the tracking system has determined has been probed by the gas sensor probe 1. Figure 5 shows the same display as Figure 4 with a plurality of markers 4 indicating the locations of possible leak points. It can be seen that in use the user would be aware that one possible leak point 4 has not been checked as it shows no tracking shading 21a. A 3D view (not shown) may be available for manipulation via a computing means (also not shown). It will be appreciated that the number of markers may vary depending on the situation and may be a configurable value of the system. The term ‘possible leak point’ refers, generally, to points on the device where a leak may occur, or where a leak is suspected to have occurred. The possible leak points in Figure 5 are labelled by a plurality of markers 4, but it will be appreciated that the possible leak points may be indicated to the user by another means, such as by aural feedback rather than displayed on screen. A possible leak point may be generated in a number of ways. In one embodiment, the locations of possible leak points are identified automatically by the tracking system based at least in part on measurements of concentration of a gas recorded by the gas sensor probe 1 at said locations. The identification of leak points may comprise inferring values of the concentration of a gas between measurements taken by the gas sensor probe 1 at other locations. In some embodiments, the locations of possible leak points are input into the system by the user 30, such that they may appear as one or more markers 4 on the display 20. In other embodiments, the locations of possible leak points on similar devices to be leak tested 10 may be stored in a computing means and then displayed on the display 20. Figure 6 shows a heat map 22a. The lightest shading 23a shows no / minimal gas detected, or a minimum concentration of gas detected. Medium shading 23b indicates elevated levels of (i.e., elevated concentration of) a gas being detected and the heaviest shading 23c shows high levels of (i.e., high concentration of) a gas being detected, thus indicating the potential source(s) of a leak. Figure 7 shows the same display as Figure 6 with markers 4 for possible leak points located at or near the potential source(s) of a leak. In Figure 7, two markers are located on top of the device to be leak tested 10 (the side furthest from the stand), they are each labelled by a marker 4 indicating that they are the potential source(s) of the leaking gas. The tracking system determines where to display a marker 4 based at least in part on the determination that the region of heaviest shading 23c is adjacent to a portion of the device to be leak tested 10. A 3D view (not shown) may be available for manipulation via a computing means (also not shown). The invention is not intended to be restricted to the details of the above-described embodiment. For instance, the type of gas to be detected, and the gas sensor are not intended to be limiting. The present invention is intended for use when leak testing devices which have been pressurised internally. For example, the present invention is intended for use in leak testing devices which contain a pressurised gas. The present invention is not necessarily intended to be limited to tracking nodes, any tracking means may be used including those developed in future. It will be understood that the invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention. Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination. 5 Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

1. A system for detecting gas leaks comprising:a gas sensor probe; anda tracking system;wherein the tracking system comprises at least one tracking device configured to determine a location of the gas sensor probe; andwherein the gas sensor probe is configured to detect a gas at the determined location.

2. A system according to Claim 1, wherein the at least one tracking device comprises a tracking device coupled to the gas sensor probe.

3. A system according to Claim 1 or 2, wherein the at least one tracking device comprises multiple tracking devices coupled to the gas sensor probe.

4. A system according to any preceding claim, further comprising at least one structure separate from the gas sensor probe, wherein the at least one tracking device comprises a tracking device coupled to the structure.

5. A system according to Claim 4, wherein the at least one tracking device comprises multiple tracking devices coupled to the at least one structure.

6. A system according to Claim 4 or 5, wherein the at least one structure comprises at least one stand, at least one frame, or a housing, separate from the gas sensor probe.

7. A system according to any of Claims 4 to 6 as dependent on either Claim 2 or 3, wherein the tracking system is configured to determine the location of the gas sensor probe based at least in part on an interaction between the at least one tracking device coupled to the gas sensor probe and the at least one tracking device coupled to the structure.

8. A system according to any preceding claim, comprising a computing device configured to receive data from the gas sensor probe and from the tracking system.

9. A system according to Claim 8, wherein the computing device is configured to associate the data received from the gas sensor probe with the data received from the tracking system.

10. A system according to Claim 9, wherein the computing device is configured to associate the data received from the gas sensor probe with the data received from thetracking system based on the time at which the location of the gas sensor probe is determined and the time at which the gas is detected at the determined location.

11. A system according to any of Claims 8 to 10, wherein the data received from the gas sensor probe comprises data relating to a concentration of the detected gas measured by the gas sensor probe.

12. A system according to Claim 11, wherein the computing device is configured to compare the measured concentration to a threshold concentration.

13. A system according to Claim 11 or 12, wherein the computing device is configured to infer, based at least in part on the data relating to the concentration of the detected gas at one or more locations, the location of at least one potential gas leak.

14. A system according to any of Claims 11 to 13, wherein the computing device is configured to generate a heatmap indicating the concentration of the gas detected at one or more locations.

15. A system according to Claims 12 and 14, wherein the computing device is configurated to indicate on the heatmap locations at which the measured concentration of the gas exceeds the threshold concentration.

16. A system according to Claims 13 and 14, wherein the computing device is configurated to indicate on the heatmap the inferred location of the at least one potential gas leak.

17. A system according to any of Claims 8 to 16, wherein the computing device is configured to generate a tracking map indicating regions that have been probed by the gas sensor probe and / or regions that have not been probed by the gas sensor probe.

18. A system according to Claim 17, wherein the computing device is configured to indicate on the tracking map regions containing a potential gas leak, preferably wherein the regions containing a potential gas leak are inferred from the data received from the gas sensor probe and / or the data received from the tracking system and / or from information relating to a device being tested by the system for gas leaks.

19. A system according to Claim 17 or 18, comprising a user interface to enable a user to input a location of a potential gas leak.

20. A system according to Claim 19, wherein the computing device is configured to indicate on the tracking map the user input location of the potential gas leak.

21. A system according to Claim 20 wherein the system is configured to:remove the indication of the user input location of the potential gas leak from the tracking map upon determining that the user input location of the potential gas leak has been probed by the gas sensor probe; and / or5 issue an alert to a user upon determining that the location of the potential gas leakhas not been probed by the gas sensor probe.

22. A system according to any of Claims 14 to 21, comprising a display configured to display the heatmap or the tracking map to a user.

23. A system according to Claim 22, wherein the display is configured to display a visual 10 indicator in relation to the heatmap or tracking map to guide the user to probe a particular location.

24. A system according to Claim 22 or 23, wherein the display is configured to display a visual depiction of a device being tested by the system for gas leaks.

25. A system according to Claim 24, wherein the display is configured to display an15 indication of the determined location of the gas sensor probe in relation to the visually depicted device.

Images