AU2011200339A1

AU2011200339A1 - A system for and a method of authorising at least partial filling of a container with a fluid

Info

Publication number: AU2011200339A1
Application number: AU2011200339A
Authority: AU
Inventors: William John Crosse
Original assignee: CROSSECOM Pty Ltd
Current assignee: CROSSECOM Pty Ltd
Priority date: 2010-01-27
Filing date: 2011-01-27
Publication date: 2011-08-11
Anticipated expiration: 2031-01-27
Also published as: AU2011200339B2

Abstract

Abstract A system for authorising at least partial filling of a container with a fluid is disclosed. The system comprises 5 a tag associated with the container, the tag comprising tag information and being configured to allow wireless reading of the tag information upon receiving a trigger signal. The system further comprises a reader for wirelessly reading the tag information and means for io receiving a signal from the reader and transferring a trigger signal to the tag. The system is arranged to receive the tag information from the reader and to use the tag information to determine whether to allow at least partial filling of the container. 2545527_1 (GHMatters) 27/01/11

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): Crossecom Pty Ltd Invention Title: A SYSTEM FOR AND A METHOD OF AUTHORISING AT LEAST PARTIAL FILLING OF A CONTAINER WITH A FLUID The following statement is a full description of this invention, including the best method for performing it known to me/us: -2 A SYSTEM FOR AND A METHOD OF AUTHORISING AT LEAST PARTIAL FILLING OF A CONTAINER WITH A FLUID Field of the Invention 5 The present invention relates to a system for and a method of authorising at least partial filling of a container with a fluid. 10 Background of the Invention Gas cylinders may be used for storing fluids such as compressed natural gas (CNG). The high pressures involved in storing CNG, and the volatile nature of CNG, has led to is requirements such as the periodic inspection and testing of the integrity of gas cylinders in an effort to improve safety. When gas cylinders are due to be refilled, the last 20 inspection date of the cylinder should be checked. If the gas cylinder is only refilled when the last inspection date of the gas cylinder falls within a valid range, safety is improved since the integrity of the gas cylinder is guaranteed to have been checked within a prescribed 25 timeframe. To further improve safety, a maximum safe capacity of the cylinder may also be checked and the gas cylinder not be filled beyond this capacity. However, such checks are often conducted manually and, as 30 such, may not be conducted correctly or at all. Some attempts have been made to overcome this problem by providing automated checking systems. Some automated checking systems associate an identifier such as a radio frequency identification (RFID) device with the container, 35 and the identifier is read to perform an automatic check. However, if a cylinder is located remote from the device used to read the cylinder, an automatic check may be 25455271 (GHMatters) 25/0111 - 3 prevented from occurring. Summary of the Invention 5 In accordance with a first aspect of the present invention, there is provided a system for authorising at least partial filling of a container with a fluid, the system comprising: a tag associated with the container, the tag io comprising tag information and being configured to allow wireless reading of the tag information upon receiving a trigger signal; a reader for wirelessly reading the tag information; and is means for receiving a signal from the reader and transferring a trigger signal to the tag; the system being arranged to receive the tag information from the reader and to use the tag information to determine whether to allow at least partial filling of 20 the container. The signal received from the reader and transferred to the tag may be the trigger signal. The trigger signal may be an energisation signal for energising the tag. 25 The tag information may comprise identification information usable to obtain stored information relating to a date on which an inspection of the container was last performed and/or information relating to a filling 30 capacity of the container. Further, or alternatively, the tag information may comprise information relating to a date on which an inspection of the container was last performed and/or 35 information relating to a filling capacity of the container. The inspection information may be verified against stored reference inspection information. The 2545527_1 (GHMatters) 25101111 -4 filling capacity information may be verified against a reference allowable filling capacity. In determining whether or not to allow the at least 5 partial filling of the container, the system may determine whether the period between the current date and the last inspection date of the container falls within a predefined range. If this is the case, then the at least partial filling of the container is allowed to commence, otherwise 10 the system does not allow the at least partial filling to commence and may further be arranged to sound an alert or similar as notification that the container is due for inspection. is The system may also be arranged to use the information relating to the filling capacity of the container to prevent the filling of the container beyond the container's filling capacity. This may comprise obtaining filling information from a dispenser of the fluid and 20 using this filling information to stop the filling of the container beyond the container's filling capacity. The system may be arranged to compare the filling capacity information associated with the container's tag with an 25 estimated filling capacity obtained during an initial partial filling of the container. This comparison may be used to determine whether a further container has been placed in fluid communication with the container. 30 Allowing such a determination to be made may prevent further filling of the further container. In one embodiment, the estimated filling capacity is obtained by measuring a change in pressure of the 35 container during the initial partial fill, measuring a mass of the fluid input during the initial partial fill, and calculating the estimated filling capacity of the 2545527_1 (GHMatters) 25/01111 - 5 container based on these measurements. If the comparison between the estimated filling capacity and the filling capacity information of the tag is greater 5 than an error margin, then the system may be arranged to generate an alert which may be used to prevent further filling, or to raise an alert that further filling requires authorisation or to authorise more partial fillings to recheck the calculations. 10 If the system determines that a further container has been placed in fluid communication with the first container and further filling is prevented, the system may be arranged to allow an authorised person to override the system and 15 allow further filling in accordance with appropriate safety procedures. Details of this override and the person who authorised it may be recorded for accountability purposes. Alternatively, the system may be arranged to prevent any such override from being made. 20 The first container may be a plurality of containers, each having an associated tag and/or tag information. The system may comprise a pressure measurement device for 25 taking the first and second pressure measurements. The system may comprise a device for measuring the mass of fluid partially filled into the first container. Alternatively, the mass and/or pressure measurements may be obtained from a dispenser of the fluid. 30 In one embodiment, the tag is a passive RFID tag that is energisable by electromagnetic radiation produced by the reader to allow the RFID tag to wirelessly transmit the tag information to the reader. In this embodiment, the 35 means for receiving a signal from the reader and transferring a trigger signal to the tag provides a means for allowing the reader to energise the tag when the tag 2545527_1 (GHMatters) 25/01111 -6 is remote from the reader. The means for receiving a signal from the reader and transferring a trigger signal to the tag provides the 5 significant advantage of allowing the tag to be energised by the reader when it would otherwise be located too far from the reader for sufficient energisation to occur. Using a passive RFID tag as the tag provides the advantage io of improving safety when the system is used with containers for holding volatile fluids such as CNG since risks associated with using an active (powered) RFID are reduced. Further, using a passive RFID tag provides the advantage of not requiring the RFID tag to have its own 15 power source or to be wired for power, such as to a vehicle's electrical system, as may be the case for an active RFID tag. Further, the means for receiving a signal from the reader 20 and transferring a trigger signal to the tag allows the reader to use relatively low power electromagnetic radiation for energising the tag. This may improve safety when, for example, the fluid is flammable. 25 The tag may be fixed to the container. In one embodiment, the tag is fixed in a manner such that removal of the tag from the container renders the tag inoperable. The tag may be fixed to the container by means of a thermosetting polymer such as epoxy. 30 The container may be a gas cylinder for containing fluid such as compressed natural gas (CNG). The filling capacity of the gas cylinder may be the maximum pressure that the cylinder can be safely filled to. 35 In the embodiment wherein the tag is a passive RFID tag, the means for receiving a signal from the reader and 25.45527_1 (GHMatters) 25/01111 -7 transferring a trigger signal to the tag may comprise a conductor comprising a first region arranged in the vicinity of the coil of the RFID tag and a second region arranged in the vicinity of the reader wherein an 5 electromagnetic signal produced by the reader at the second region causes a corresponding electromagnetic signal to be produced at the first region. In one embodiment, the conductor comprises a first coil at the first region and a second coil at the second region. 10 Accordingly, an electromagnetic signal from the reader will interact with the second coil so as to induce a current in the conductor which in turn produces an electromagnetic signal at the first coil for energising the RFID tag. 15 In one embodiment, the second region is in the vicinity of a filling point of the container. The container is remote from, but in fluid communication with, the filling point. The reader may be mounted on a filling device such as a 20 CNG dispenser nozzle such that the reader is in the second region and therefore capable of energising the tag when the container is to be at least partially filled. The means for receiving a signal from the reader and 25 transferring a trigger signal to the tag may comprise means for tuning the electromagnetic signal from the reader so as to tune the electromagnetic signal to an appropriate frequency for energising the RFID tag. The means for tuning may comprise a tuning condenser or any 30 other appropriate circuitry or components arranged for tuning electromagnetic signals. In accordance with a second aspect of the present invention, there is provided a refilling system comprising 35 an authorisation system in accordance with the first aspect of the present invention, and a dispenser for dispensing the fluid into the container wherein the 2545527_1 (GHMatters) 25101111 -8 dispenser is arranged to be controllable by the authorisation system to allow the at least partial filling of the container based on the determination. 5 The refilling system may comprise an authorisation controller that is in communication with the authorisation system. The authorisation controller may store the inspection and/or filling capacity information relating to the container. The information stored by the authorisation 10 controller may be updated upon receiving more recent information from the authorisation system. The authorisation controller may be configured to automatically check payment and/or banking details of an owner of the container to be filled, or a person paying is for the refilling, and to determine whether or not to allow the at least partial filling based on this information. Further, or as an alternative, at least some of the 20 information may be stored and updated on the tag. The authorisation controller may comprise pricing information usable to determine the cost of filling, or be in communication with a pricing controller or similar for 25 this same purpose. In accordance with a third aspect of the present invention, there is provided a method of authorising at least partial filling of a container with a fluid, the 30 method comprising: generating an energisation signal for energising a tag; receiving the energisation signal and transferring the energisation signal to the tag; 35 energising the tag via the transferred energisation signal, the tag comprising tag information and being configured to allow wireless reading of the tag 2545527_1 (GHMatters) 25/01/11 -9 information; transmitting tag information from the tag; determining whether to allow at least partial filling of the container based on the transmitted tag information. 5 In accordance with a fourth aspect of the present invention, there is provided a system for extending the range at which tag information of a RFID tag associated with a container may be read by a reader, the system 10 comprising: a RFID tag associated with the container, the RFID tag comprising tag information and being configured to allow wireless reading of the tag information by the reader; and is means for receiving a signal from the reader and transferring an energisation signal to the RFID tag so as to energise the RFID tag. The means for transferring an energisation signal to the 20 RFID tag may comprise a conductor comprising a first region arranged in the vicinity of an energising coil of the RFID tag and a second region arranged in the vicinity of the reader wherein an electromagnetic signal produced by the reader at the second region causes a corresponding 25 electromagnetic signal to be produced at the first region. In one embodiment, the conductor comprises a first coil at the first region. The conductor may also comprise a second coil at the second region. Accordingly, an electromagnetic 30 signal from the reader may interact with the second coil so as to induce a current in the conductor which in turn produces an electromagnetic signal at the first coil for energising the RFID tag. 35 In one embodiment, the second region is in the vicinity of a filling point of the container. The container is remote from, but in fluid communication with, the filling point. 2545527_1 (GHMatters) 25/01/11 - 10 The reader may be mounted on a filling device such as a CNG dispenser nozzle such that the reader is in the second region and therefore capable of energising the tag when the container is to be at least partially filled. 5 The means for transferring an energisation signal to the RFID tag may comprise means for tuning the electromagnetic signal from the reader so as to tune the electromagnetic signal to an appropriate frequency for energising the RFID 10 tag. The means for tuning may comprise a tuning condenser or any other appropriate circuitry or components arranged for tuning electromagnetic signals. In accordance with a fifth aspect of the present 15 invention, there is provided a method of installing the system of the fourth aspect such that the tag is attached to the container and arranged such that removal of the tag or significant tampering with the tag will render the system inoperable. This may prevent the filling of the 20 container if, for example, the tag or a connection to the tag is removed or replaced with other parts in an attempt to circumvent the authorisation system. In one embodiment, at least a portion of an energising 25 coil of the RFID tag is attached to the container or near the container such that the energising coil is rendered inoperable when removed from the container. In a further embodiment, the first coil of the conductor is attached to the RFID tag or near the RFID tag such that the first coil 30 is rendered inoperable when removed from the container. In accordance with a sixth aspect of the present invention, there is provided a system for extending the range at which tag information of a RFID tag associated 35 with a container may be read by a reader and being arranged to prevent tampering, the system comprising: a RFID tag attached to the container, the RFID tag 2545527_1 (GHMatters) 25/01/11 - 11 comprising tag information and being configured to allow wireless reading of the tag information by the reader; and means for receiving a signal from the reader and transferring an energisation signal to the RFID tag so as 5 to energise the RFID tag; the RFID tag being arranged such that removal of the RFID tag from the container or significant tampering with the RFID tag results in the tag being inoperable. 10 In one embodiment, an energising coil of the RFID tag is connected to the RFID tag such that the energising coil becomes inoperable if the RFID tag is removed from the container. 15 In another embodiment, a portion of the means for transferring the energisation signal to the RFID tag is connected to the RFID tag such that the portion becomes inoperable if the RFID tag is removed from the container. 20 In accordance with a seventh aspect of the present invention, there is provided a method of determining whether a container is in fluid communication with a further container, the method comprising the steps of: measuring a change in the pressure of a container 25 when the container is partially filled with a fluid; measuring an amount of fluid input into the container during the partial fill; calculating an estimated filling capacity of the container from the measurements; 30 obtaining filling capacity information associated with the container by using a tag associated with the container; and comparing the estimated filling capacity of the container with the filling capacity information obtained 35 by using the tag so as to determine whether a further container has been placed in fluid communication with the container. 2545527_1 (GHMatters) 25101/11 - 12 The filling capacity information may be obtained directly from the tag. Alternatively, identification information associated with the tag may be used to obtain the filling 5 capacity information from a database or similar. The method may further comprise the step of preventing further filling of the container if the comparison between the estimated filling capacity and the filling capacity 10 information of the container differs by more than a predetermined threshold or to authorise more partial fillings to recheck and/or refine the calculations. The predetermined threshold may be an error margin 15 associated with the measurements and/or the calculation. Brief Description of the Drawings Embodiments of the present invention will now be 20 described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic diagram of a refilling system which incorporates an authorisation system for authorising 25 at least partial filling of a container with a fluid in accordance with an embodiment of the present invention; Figure 2 is a cut away perspective view of a vehicle showing the vehicle fitted with a portion of the 30 authorisation system of Figure 1; Figure 3 is a flow diagram showing a method of authorising at least partial filling of a container with a fluid in accordance with an embodiment of the present invention; 35 Figure 4 is a flow diagram showing a method of authorising at least partial filling of a container in accordance with 2545527_1 (GHMatters) 25/01/11 - 13 an embodiment of the present invention; and Figure 5 is a flow diagram showing a method of determining whether a container is in fluid communication with a 5 further container in accordance with an embodiment of the present invention. Detailed Description of the Specific Embodiments 10 Embodiments of the present invention relate to an authorisation system and a method of authorising the refilling of gas cylinders with compressed natural gas (CNG) or other fluids. 15 In general, the authorisation system comprises a tag comprising tag information, the tag being associated with the gas cylinder; a reader for reading the tag information; and means for communicating a signal from the reader to the tag. The signal that is communicated from 20 the reader to the tag may allow for energisation of the tag. The system is arranged to use the tag information to determine whether to allow the gas cylinder to be refilled. 25 In specific embodiments, the system utilises wireless transmission devices. As such, the tag is configured to allow wireless reading of the tag information; the reader is arranged for wirelessly reading the tag information; and the means for communicating a signal from the reader 30 to the tag allows the tag to be energised by the reader when the reader is remote from the tag. This allows the tag information to then be read when the tag is remote from the reader. This is often the case with vehicles having a gas cylinder located in the boot or another 35 location remote from a filling point of the vehicle. In the examples that follow, the authorisation system 2545527_1 (GHMatters) 25/01/11 - 14 makes use of passive RFID tags and low power RFID readers appropriate for use with refilling systems that dispense volatile fluids such as CNG. This also allows the use of a tag that does not need to be wired to the vehicle's 5 electrical system as may be the case if active RFID tags were used. However, this necessitates the need for providing means for communicating a signal from the RFID reader to the RFID tag so as to allow the RFID reader to read the tag information of the RFID tag. Since the RFID 10 tag is passive, it is required to be energised by the RFID reader. Therefore, in situations where the RFID tag is remote from the RFID reader, the means for communicating a signal from the RFID reader to the RFID tag provides a way of energising the RFID tag by the RFID reader despite the is distance between the RFID tag and the RFID reader. A specific example of a filling station incorporating an authorisation system for authorising refilling of a gas cylinder with CNG is now described with reference to 20 Figure 1. Figure 1 shows a refilling station 100 for refilling a natural gas vehicle 102, 202. The vehicle 102, 202 (also shown in Figure 2) comprises a CNG gas cylinder 104, 204 having a RFID tag 106, 206 attached thereto. The RFID tag 106, 206 comprises tag information 25 including identification information and an energising coil 107 (not shown in Figure 2) for powering the RFID tag 106, 206. In this example, the gas cylinder 104, 204 is remote from a filling point 110, 210 and is connected to the gas cylinder 104, 204 by means of a gas line 108, 208. 30 In this case, the gas cylinder 104, 204 is arranged at the rear of the vehicle 102, 202, however the filling point 110, 210 is arranged at the front of the vehicle 102, 202. In this example the RFID tag 106, 206 is epoxied to the gas cylinder 104, 204. It will be appreciated, however, 35 that the RFID tag 106, 206 may be fixed to the gas cylinder 104, 204 by any appropriate means. 25455271 (GHMatters) 25/01111 - 15 When the gas cylinder 104 is to be refilled, a dispenser nozzle 122, which is in communication with a CNG dispenser 118 by means of dispenser hose 120, is connected to the filling point 110. A RFID reader antenna 124 is mounted 5 on the dispenser nozzle 122 and comprises a small loop antenna with relatively low power characteristics so as to improve the safety of its use with flammable fluids such as CNG. The RFID reader antenna 124 is connected by means of an insulated cable (not shown) to a RFID reader 125 10 connected to or on the CNG dispenser 118. It will be appreciated that the RFID antenna 124 may be in communication with the RFID reader 125 by other means, for example by means of a wireless communications connection. The RFID reader antenna 124 is used to power the RFID tag 15 106 by energising the energising coil 107. This then allows the RFID tag 106 to transmit the tag information to the RFID reader 125. Due to the relatively low power of the RFID reader antenna 20 124 and the distance between the filling point 110 and the RFID tag 106, there is provided a means for communicating a signal from the RFID reader antenna 124 to the RFID tag 106. In this example, this means is provided by a conductor 112 comprising a first coil 114 and a second 25 coil 116, the conductor 112 being arranged between the filling point 110 and the RFID tag 106. The conductor 112 is arranged such that the first coil 114 is arranged in the vicinity of the energising coil 107 of the RFID tag 106 and the second coil 116 is arranged in the vicinity of 30 the filling point 110. In this way, the RFID reader antenna 124 produces a radio frequency signal which interacts with the second coil 116 so as to induce a current in the conductor 112 which in turn produces a radio frequency signal at the first coil 114. The radio 35 frequency signal produced at coil 114 interacts with energising coil 107 of the RFID tag 106 so as to energise the RFID tag 106. 2545527_1 (GHMatters) 25/01/11 - 16 The means for communicating a signal from the RFID reader antenna 124 to the RFID tag 106 may also include means for tuning (not shown) the radio frequency signal to an 5 appropriate frequency for energising the RFID tag 106. For example, the signal that is used to energise the RFID tag 106 may be detuned as a result of being carried by the conductor 112. Including means for tuning this signal will allow for such detuning to be compensated for. 10 Further, since the length of the conductor may affect the amount that the signal is detuned, including the tuning means allows the length of conductor 112 to be varied so that a standard tuning does not need to be relied upon. is For example, the conductor 112 may vary in length depending on the distance between the filling point 110 and the RFID tag 106 which may depend on the type of vehicle with which the system is used. Accordingly, the conductor 112 and the first and second coils 114, 116 may 20 be fitted to a vehicle and the tuning means may be used to compensate -for the length of the conductor 112. The tuning means may comprise a tuning condenser or any other appropriate circuitry or components arranged for 25 tuning electromagnetic signals. The energised RFID tag 106 can now transmit the tag information to be picked up by the RFID reader antenna 124 30 and passed on to the RFID reader 125 via the insulated cable. Upon transmitting the tag information from the RFID tag 106 back to the RFID reader 125, the tag information is transmitted to an authorisation controller 126 which, in this example, is located in a site office 128. The 35 authorisation controller 126 uses the tag information to determine whether to allow the gas cylinder 104 to be refilled. 2545527_1 (GHMatters) 25/01/11 - 17 The authorisation system may also incorporate an optional panel reader (not shown) for driver identification purposes. The panel reader may comprise a pinpad for 5 odometer entry or the entry of other desirable information. The driver's identification information and other entered information may be used by the authorisation system to conduct further checks such as verification checks. 10 In this example, the authorisation controller 126 comprises stored reference information relating to a date on which the integrity of the cylinder 104 was last inspected and tested. The authorisation controller 126 may 15 also comprise reference information relating to a filling capacity of the cylinder 104. For example, the filling capacity may indicate a maximum pressure that the cylinder 104 may be filled to. 20 The authorisation controller 126 uses the tag information received from the RFID reader 125 to retrieve the stored reference inspection and filling capacity information. The inspection information is then checked by the authorisation controller to determine whether the period 25 between the current date and the last date on which gas cylinder 104 was checked falls within a valid range. If this check is successful, then the authorisation controller 126 allows dispenser 118 to dispense CNG at the filling point 110 so as to refill gas cylinder 104. 30 If the filling is allowed, filling information obtained from the dispenser 118 may be used to prevent filling the cylinder 104 beyond the filling capacity of the cylinder 104. This is achieved in the current example by checking 35 that the pressure of the cylinder 104 as measured by the dispenser 118 does not exceed a maximum pressure rating of the cylinder 104 during refilling. 25455271 (GHMatters) 25/01/11 - 18 Further, or alternatively, information such as the inspection and filling capacity information may be stored on the RFID tag 106, and this is checked for the same 5 purposes as described above. For example, the RFID tag 106 may be used to record the volume of CNG input, and this may be checked, in cooperation with information obtained from the dispenser 118, to prevent filling the gas cylinder 104 beyond a maximum filling capacity. 10 Similarly, the inspection information can be stored on the RFID tag 106 and the check to determine whether to allow filling can be coordinated in a similar manner to that defined previously. 15 The RFID tag 106, 206 may be a passive RFID device in the form of a small batteryless electronic data storage unit (20-50mm in diameter) epoxied to the CNG cylinder. The RFID tag 106, 206 can contain information such as certified filling expiry date, cylinder capacity, vehicle 20 details, owner identification, driver information etc. The manner in which the RFID tag 106, 206 release its details to the RFID reader 125 may employ two-way authentication allowing only genuine authorised tags to be used and, to prevent fraud, a high security challenge and 25 response crypto-algorithm is used. In this example, the authorisation controller 126 stores reference information on all authorised cylinders and vehicles to be used with the refilling station 100 and the 30 vehicles' respective owners. This information, including inspection dates and filling capacity information of each cylinder, is continually updated and shared between further refilling stations connected to refilling station 100 via a network. The authorisation controller 126 can 35 interface with refilling station devices/outlets such as RFID readers and point of sale devices. 2545527_1 (GHMatters) 25/01/11 - 19 The authorisation controller 126 checks the information obtained from the tag against available reference information on that particular cylinder and vehicle and, if necessary, initiates automatic communication with the 5 company's head office, banks etc. to obtain authorisation. In the case where the cylinder and/or vehicle is not authorised for fuelling or if it has been reported stolen or missing, a suitable alert can be raised. The authorisation controller 126 may enable vehicles to be io refilled based on local information if communication with information stored on the network, such as information stored by an authorisation controller of a further refilling station or information stored by a central system, is temporarily unavailable. 15 The authorisation controller 126 may be in communication with a central system (not shown) that comprises a number of different applications for assisting in the control of the networked refilling stations. These applications are 20 responsible for the central price file maintenance, tag information database and authorisation process as well as production of various management reports. The system, or parts of the system, may be arranged such 25 that removal of, or significant tampering with, a part of the system will render the system, or at least that part of the system, inoperable. This may prevent the filling of the container if, for example, parts are removed or replaced with other parts in an attempt to circumvent the 30 authorisation system. In one embodiment, at least a portion of an energising coil of the RFID tag is attached to the container or near the container such that the energising coil is rendered 35 inoperable when removed from the container. In a further embodiment, the first coil of the conductor is attached to the RFID tag or near the RFID tag such that the first coil 25455271 (GHMatters) 25/01/11 - 20 is rendered inoperable when removed from the container. For example, the energising coil of the RFID tag or the first coil of the conductor may be adhered to the 5 container such that removal of the energising coil of the RFID tag or the first coil of the conductor will cause the energizing or first coil to become inoperable. A method of authorising the at least partial filling of a 10 container will now be described with reference to Figure 3 and Figure 4. Figure 3 is a flow diagram showing a method of authorising at least partial filling of a gas cylinder with a fluid is such as compressed natural gas. In a first step 302, an energisation signal is generated, for example by an antenna of a RFID reader. This energisation signal is then received and transferred 304 20 to a tag such as a passive RFID tag, such as by means of the conductor and coil arrangement described in relation to the authorisation system. This energisation signal then energises 306 the tag. The energised tag is then able to transmit 308 tag information of the tag to a reader such 25 as the RFID reader. In one embodiment the information is passed in encrypted format. This tag information is then used to determine 310 whether to allow the gas cylinder to be filled. 30 A flow chart detailing the determination 310 is shown in Figure 4. In a first step 402, the gas cylinder's identification information is received, for example by the authorisation controller 126. A check 404 is made wherein the difference between the current date and the last 35 inspection date of the gas cylinder is compared with a predefined valid range. If the difference between the current date and the last inspection date of the gas 2545527_1 (GHMatters) 25/01/11 - 21 cylinder does not fall within this range, then the dispenser 118 is not allowed 406 to fill the container. If the difference between the current date and the last inspection date does fall within a predefined range, then 5 instructions 408 are sent to the dispenser 118 so as to allow at least partial filling of the container. While the container is being filled, a pressure of the gas cylinder may be checked 410, such as by obtaining filling io information from the dispenser 118, for comparison with filling capacity information read from the gas cylinder's tag, or obtained from stored reference information. If the pressure is below the maximum safe pressure that corresponds to the gas cylinder's filling capacity, 15 filling is allowed to be continued. However, if the container has been filled to its filling capacity filling is ended 412. Further, or alternatively, the gas cylinder's filling 20 capacity may be measured by recording the volume of CNG input into the gas cylinder on the gas cylinder's tag and stopping filling when the maximum capacity of the gas cylinder has been reached. 25 It will be appreciated that obtaining filling information from the dispenser 118 may require communication of such information from the manufacturer or operator of the dispenser 118. However, it will be appreciated that checking the date that the container was last inspected is 30 not dependent on the filling information, and the system may be arranged such that filling information is not required or used to allow the at least partial filling of the container. 35 The filling capacity information associated with the RFID tag 106 may be used to make a comparison with an estimated filling capacity of the cylinder 104 obtained during an 2545527_1 (GHMatters) 25/01/11 - 22 initial partial filling of the cylinder 104. This comparison may be used to determine whether a further cylinder has been placed in fluid communication with the cylinder 104, and to prevent any further filling from 5 occurring. For example, after it has been determined to allow the cylinder 104 to be filled, measurements may be taken during an initial partial filling of the cylinder 104 so 10 as to obtain an estimate of the filling capacity of the cylinder 104. If this estimated filling capacity differs beyond a predetermined threshold from the filling capacity information associated with the RFID tag 106, further filling may be prevented from occurring. 15 Method 500, shown in Figure 5, is an example of one way to achieve this. A first step 502 comprises measuring a change in the pressure of the cylinder 104 during partial filling of the cylinder 104. In this example, partial 20 filling is used to estimate the filling capacity of the cylinder 104 and, as such, only a relatively small amount of fluid is input. The mass of CNG input into the cylinder 104 is also measured in a second step 504. Multiple fillings may be used to increase accuracy in estimating 25 the filling capacity of cylinder 104. It may be necessary to obtain a first pressure reading by inputting a first amount of CNG into the cylinder 104, and to obtain a second and subsequent pressure readings by 30 inputting second and subsequent amounts of CNG into the cylinder 104. If multiple fills are necessary, the pressure differences are the difference between the first and second or subsequent pressure readings and the mass of the CNG is the mass of the second or subsequent amounts of 35 CNG dispensed into the cylinder. In a third step 506, the measured change in pressure of 2545527_1 (GHMatters) 25/01/11 - 23 the cylinder 104 and the mass of CNG input into the cylinder 104 during partial filling of the CNG input into the cylinder 104 are used to calculate an estimated filling capacity of the cylinder 104. 5 In a specific example, the estimated filling capacity of the container is calculated from the equation: x = m / [(pr - pi)/Pi] Where: 10 x represents the estimated filling capacity; m represents the mass of the CNG input into the cylinder 104 during the partial fill; pi represents the initial pressure of the cylinder 104 prior to the partial fill; and 15 pf represents the final pressure of the cylinder 104 after the partial fill. The [ (pr - pi) /pi] portion of the formula will indicate the percentage increase in pressure of the cylinder during the 20 partial fill. To illustrate use of this formula, 1 kg of CNG is input into the cylinder 104 and the pressure of the cylinder 104 is measured to increase by 1% (ie: [(pr - pi)/pi] = 0.01). 25 The estimated filling capacity of the cylinder 104 is therefore: x = 1/0.01 = 100kg It will be appreciated that any other appropriate 30 calculation may be used, and the calculation may take into account other variables such as temperature. In a fourth step 508, filling capacity information associated with the cylinder 104 is obtained by using the 35 RFID tag 106 associated with the cylinder 104. The filling capacity information may be obtained directly from the RFID tag 106, or indirectly by using identification 2545527_1 (GHMatters) 25/01/11 - 24 information associated with the RFID tag 106 to obtain the filling capacity information from the reference information store by the authorisation controller 126. 5 In a fifth step 510, the estimated filling capacity of the cylinder 104 is compared with filling capacity information obtained using the RFID tag 106. f the comparison reveals that the estimated filling capacity and the filling capacity information differ by more than a predetermined 10 threshold, such as an error margin determined from the pressure and mass measurements and/or calculation, then it may be an indication that a further cylinder has been placed in fluid communication with the cylinder 104 and further filling may be prevented from occurring. 15 The method 500 may also be used with a plurality of cylinders in fluid communication with one another and wherein each of the cylinders has a tag associated with it. Each tag may comprise or be used to obtain a filling 20 capacity of its associated cylinder. Accordingly, the above example may be extended wherein the total filling capacity of the cylinders is calculated by adding the capacities of the individual cylinders and this may be compared to an expected filling capacity as derived from a 25 method similar to that described above. Accordingly, if a further cylinder has been placed in fluid communication with the plurality of cylinders and the further cylinder does not have an associated tag or tag information, the expected filling capacity and the filling capacity 30 information may differ and further filling may be prevented. The authorisation system of the filling station may be arranged to allow the method 500 to be conducted. For 35 example, the dispenser nozzle 122 may have a pressure gauge for providing the pressure readings, and the dispenser 118 may provide information indicating the mass 2545527_1 (GHMatters) 25/01/11 - 25 of CNG input into the cylinder 104 during the partial fill. The pressure readings and mass information may be communicated to the authorisation controller 126, which may be arranged to perform the calculation to estimate the s filling capacity of the cylinder 104, and to compare the estimated filling capacity with the filling capacity information obtained using the RFID tag 106. If the comparison shows that the estimated filling 10 capacity differs from the filling capacity associated with the RFID tag 106 by an amount greater than the predetermined threshold, the authorisation controller 126 can communicate with the dispenser 118 so as to prevent further filling from occurring. 15 The authorisation system may be arranged so that, in accordance with appropriate safety procedures, an authorised person may override the authorisation controller 126 to enable filling to continue. Such a 20 situation may arise if, for example, the authorised person is satisfied after a manual inspection that the cylinder 104 does not have an unauthorised further cylinder in fluid communication with it despite an unfavourable comparison between the estimated filling capacity and the 25 filling capacity information associated with the RFID tag 106. Details of such an override, including the time of the override and identification information associated with the authorised person can be recorded by the authorisation controller 126 for accountability purposes. 30 Alternatively, the authorisation system may be arranged to prevent any overrides from being made. It will be appreciated that, although examples described 35 above relate to filling a cylinder with CNG, any fluid may be used with the system and method such as LPG, chlorine and liquid nitrogen. 2545527_1 (GHMatters) 25/01/11 - 26 It will also be appreciated that, although most examples relate to authorising the filling of a single cylinder, there may be a plurality of cylinders in fluid 5 communication with one another, each having an associated tag that is usable to obtain or derive information for the purposes of authorising filling. Alternatively, a single tag may be associated with a plurality of cylinders, wherein the tag is usable to obtain or derive information 10 in respect of the plurality of cylinders. For filling of the plurality of cylinders to occur, successful authorisation for filling each cylinder may be required. For example, each tag associated with each is cylinder must be required to pass a check prior to filling or, for alternative embodiments, one tag associated with a plurality of cylinders must pass a check prior to filling. Further, these checks can be extended to the filling capacity of each cylinder, wherein filling capacity 20 information associated with each of a plurality of cylinders is monitored so as to prevent filling the plurality of cylinders to an unsafe level. It will be understood to persons skilled in the art of the 25 invention that many modifications may be made without departing from the spirit and scope of the invention. In the claims which follow and in the preceding description of the invention, except where the context 30 requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further 35 features in various embodiments of the invention. It is to be understood that, if any prior art is referred 2545527_1 (GHMatters) 25101/11 - 27 to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country. 2545527_1 (GHMatters) 25101/11

Claims

1. A system for authorising at least partial filling of 5 a container with a fluid, the system comprising: a tag associated with the container, the tag comprising tag information and being configured to allow wireless reading of the tag information upon receiving a trigger signal; 10 a reader for wirelessly reading the tag information; and means for receiving a signal from the reader and transferring a trigger signal to the tag; the system being arranged to receive the tag 15 information from the reader and to use the tag information to determine whether to allow at least partial filling of the container.

2. The system of claim 1, wherein the signal received 20 from the reader and transferred to the tag is the trigger signal.

3. The system of claim 1 or claim 2, wherein the trigger signal is an energisation signal for energising the tag. 25

4. The system of any one of the preceding claims, wherein the tag information is verified against stored reference tag information. 30

5. The system of any one of the preceding claims, wherein the tag is a passive RFID tag that is energisable by electromagnetic radiation produced by the reader to allow the RFID tag to wirelessly transmit the tag information to the reader. 35

6. The system of claim 5, wherein the means for receiving a signal from the reader and transferring a 2545527_1 (GHMatters) 25/01/11 - 29 trigger signal to the tag provides a means for allowing the reader to energise the tag when the tag is remote from the reader. 5

7. The system of claim 5 or 6, wherein the means for receiving a signal from the reader and transferring a trigger signal to the tag comprises a conductor comprising a first region arranged in the vicinity of the coil of the RFID tag and a second region arranged in the vicinity of 10 the reader wherein an electromagnetic signal produced by the reader at the second region causes a corresponding electromagnetic signal to be produced at the first region.

8. The system of claim 7, wherein the conductor 15 comprises a first coil at the first region.

9. The system of claim 7 or 8, wherein the conductor comprises a second coil at the second region. 20

10. The system of any one of claims 7 to 9, wherein the second region is in the vicinity of a filling point of the container.

11. The system of any one of claims 7 to 10, wherein the 25 reader is mounted on a filling device such as a CNG dispenser nozzle such that the reader is in the second region and therefore capable of energising the tag when the container is to be at least partially filled. 30

12. The system of any one of claims 7 to 11, wherein the means for receiving a signal from the reader and transferring a trigger signal to the tag comprises means for tuning the electromagnetic signal from the reader so as to tune the electromagnetic signal to an appropriate 35 frequency for energising the RFID tag.

13. The system of claim 12, wherein the means for tuning 25455271 (GHMatters) 25/01/11 - 30 comprises a tuning condenser.

14. The system of any one of the preceding claims, wherein the tag is fixed to the container. 5

15. The system of claim 22, wherein the tag is fixed in such a manner that removal of the tag from the container renders the tag inoperable. 10

16. The system of any one of the preceding claims, wherein the tag information comprises, or is usable to obtain, filling capacity information associated with the container, the system being arranged to compare the filling capacity information with an estimated filling i5 capacity obtained during an initial partial filling of the container.

17. The system of claim 17, wherein the estimated filling capacity is obtained by measuring a change in pressure of 20 the container during the initial partial fill, measuring a mass of the fluid input during the initial partial fill, and calculating the estimated filling capacity of the container based on these measurements. 25

18. The system of claim 16 or 17, wherein, if the comparison between the estimated filling capacity and the filling capacity information is greater than an error margin, the system is arranged to generate an alert usable to prevent further filling, to raise an alert that further 30 filling requires authorisation or to authorise more partial fillings to recheck the calculations.

19. The system of any one of the preceding claims, wherein the container is suitable for containing gas and 35 the fluid is compressed natural gas (CNG).

20. A refilling system comprising an authorisation system 2545527_1 (GHMatters) 25101/11 - 31 in accordance with any one of the preceding claims, and a dispenser for dispensing the fluid into the container wherein the dispenser is arranged to be controllable by the authorisation system to allow the at least partial 5 filling of the container based on the determination.

21. A system for authorising at least partial filling of a container with a fluid substantially as hereinbefore described with reference to at least one of the 10 accompanying drawings. 2545527_1 (GHMatters) 25/01111