GB2541071A

GB2541071A - Sensor for reading a gas meter

Info

Publication number: GB2541071A
Application number: GB1609315.5A
Authority: GB
Inventors: Richard Rowe Paul; Lightfoot Gavin; Derek Martin Robert
Original assignee: Maple Tree Energy Man Ltd
Current assignee: Maple Tree Energy Man Ltd
Priority date: 2014-03-28
Filing date: 2014-03-28
Publication date: 2017-02-08
Anticipated expiration: 2034-03-28
Also published as: GB2541071B; GB2541072A; GB201609319D0; GB201405646D0; GB2525377A; GB2541072B; GB2525377B; GB201609315D0

Abstract

A gas meter sensor for detecting movement of a rotating element of a gas meter comprises an optical sensor having an optical controller, an optical emitter and an optical detector configured to detect a reflection of optical radiation emitted by the optical emitter. The optical sensor generates a value that is proportional to the radiation received and returns a binary 1 condition if the value reaches a threshold. The apparatus then performs a calibration routine to determine an intensity of radiation to be output by the emitter during an optical measuring routine and then drives the optical emitter at a reference intensity in order to determine a rate of movement of a rotating element in a gas meter. The calibration routine comprises identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached and then varying the intensity of radiation of the emitter in order to determine the reference intensity, the reference intensity being an average intensity at which a binary 1 is returned.

Description

Sensor for reading a gas meter

The present invention concerns apparatus and methods for reading a gas meter.

There is an increasing concern to reduce the consumption of resources, both at a domestic level in residential buildings, and at a commercial level in offices, shops, factories and so forth. The reasons for this are both to save costs and also because of concerns for the environment, such as the conservation of scarce resources, for example water in regions where rainfall is low, to reduce C02 emissions, and to conserve finite resources such as coal, gas and oil.

Conventionally, consumers receive bills from utility companies which may indicate the quantity of the utility used since the last bill, for example monthly or quarterly, based on periodic meter readings or even based on estimates of consumption since the last meter reading. For example, in the case of gas supply, the information may be presented to the consumer in terms of the number of kilowatt hours of gas that has been used during the entire period, which is meaningless to many people. Studies have shown that the effect of providing consumers with real-time detailed information about the energy they are using is that their consumption reduces by up to 20%.

While a consumer is free to read a gas meter manually, this provides only a snapshot of the amount of gas that has been consumed in total. In order to obtain a more meaningful idea of gas consumption, a consumer might read the meter multiple times over an extended period and then process the data (at the very least by subtracting a current value from a previous value) in order to obtain more meaningful information that can be used to inform decisions regarding future consumption. Further data processing would be required in order to be able to attribute higher or lower periods of gas usage to particular uses of gas.

There is a wide range of gas meter technologies in current use. Some gas meters involve rotating drums comprising numbers printed on an outer surface of each drum such that, when the drum rotates with gas consumption, the numbers increment to represent the quantity being used. Other gas meters involve a dial that rotates with use and, as it rotates, passes numbers printed on a stationary background.

In the case of a rotating drum-type meter, there is generally a reflective dot located at one location on the drum (e.g. in the centre of the number 0) such that the reflective dot is visible once per rotation of the drum.

In the case of a rotating needle-type meter, there is generally no equivalent to the reflective dot. However, it is generally the case that the needle itself is of a different colour to the background against which it is located in order to provide a suitable contrast.

Some gas meters, particularly of the rotating-drum type, also include a magnet that rotates with the drum.

While it is known to use a reed switch to read a gas meter comprising a rotating magnet, such sensors are at best only appropriate for use with a meter having a rotating magnet. Moreover, since reed switches are sensitive to a magnetic field in one direction, there is limited flexibility with regard to positioning of the read switch relative to the magnet. For this and other reasons, such reed switch based magnetic sensors may not be compatible with a broad range of gas meters.

The present invention aims to alleviate, at least partially, one or more of the above problems.

In a first aspect of the invention, there is provided a gas meter sensor for detecting movement of a rotating element of a gas meter, the gas meter sensor comprising first and second sensors, wherein the first sensor is an optical sensor and the second sensor is a magnetic sensor.

Advantageously, this allows the user to monitor usage of gas in real time through use of a single gas meter sensor that is capable of reading a wide range of commercially available gas meters in a wide range of locations and ambient conditions.

In a further aspect of the invention, there is provided a gas meter sensor for detecting movement of a rotating element of a gas meter, the gas meter sensor comprising: an optical sensor having an optical controller, an optical emitter and an optical detector configured to detect a reflection of optical radiation emitted by the optical emitter, wherein the optical sensor is configured: (a) to generate a value that is proportional to radiation detected by the optical sensor; (b) to return a binary 1 if the value reaches a threshold; (c) to perform a calibration routine to determine an intensity of radiation to be output by the emitter during an optical measuring routine, the calibration routine comprising: (i) identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached in use; (ii) during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned; and (d) to drive the optical emitter at the reference intensity in order to determine a rate of movement of a rotating element in a gas meter to which the sensor may be attached in use.

Advantageously, this allows the user to monitor usage of gas in real time through use of a gas meter sensor that is capable of reading a wide range of commercially available gas meters in a wide range of locations and ambient conditions.

In a further aspect of the invention, there is provided a mounting bracket suitable for mounting a gas meter sensor, wherein the bracket comprises a gas meter sensor receiving portion for attaching at least a part of the gas meter sensor to the bracket; a first aperture adjacent the gas meter sensor receiving portion; and a fixing element for fixing the mounting bracket to a gas meter such that aperture is located adjacent a rotating element in the gas meter.

In a further aspect of the invention, there is provided a kit of parts comprising a gas meter sensor and a mounting bracket.

In a further aspect of the invention, there is provided a method of calibrating a gas meter sensor having an optical emitter and an optical detector, the method comprising: (i) identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached; (ii) during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned.

In a further aspect of the invention, there is provided a method of calibrating a gas meter sensor having a magnetometer, the method comprising: identifying if data representative of magnetic field strength of one or two of the three dimensions results in saturation of the magnetometer in those one or two dimensions during rotation of a magnet in the gas meter; and eliminating data for those one or two dimensions for the purposes of assessing rotation of the magnet during the magnetic measuring routine.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1a depicts a gas meter sensor in accordance with an embodiment of the present invention;

Figure 1b depicts the gas meter sensor of Figure 1a and also shows an adaptor plate;

Figure 2a shows a gas meter sensor head of the gas meter sensor of Figures 1a and 1b, with an adaptor plate;

Figure 2b shows a gas meter sensor head of the gas meter sensor of Figures 1a and 1b;

Figure 2c shows an exploded view of the gas meter sensor head of Figure 2a;

Figure 2d shows a cross-sectional view of the gas meter sensor head of Figures 2a to 2d;

Figure 3 shows four types of adaptor plate, each for fastening a gas meter sensor head of an embodiment of the invention to a gas meter;

Figure 4 shows an example of a typical dial-type gas meter to which a gas meter sensor may be attached;

Figure 5 shows an example of a typical drum-type gas meter to which a gas meter sensor may be attached;

Figure 6 shows an example of a typical drum- and dial-type gas meter, wherein only the least significant digit is represented by a dial, to which a gas meter sensor may be attached;

Figure 7 shows a suggested location of an adaptor plate (type B shown in Figure 3) on an example gas meter of the combined drum- and dial-type;

Figure 8 shows a suggested location of an adaptor plate on an example gas meter of the drum-type;

Figure 9 shows a suggested location of an adaptor plate on a further example gas meter of the drum-type;

Figure 10 shows a gas sensor head in accordance with the present invention being presented towards an adaptor plate adjacent a gas meter of the drum-type;

Figure 11 shows a gas sensor head in accordance with the present invention being presented towards an adaptor plate adjacent a gas meter of the dial-type;

Figure 12 shows an aspect of the method for triggering a reading of a rotation of a dial or drum of a gas meter;

Figure 13 shows as aspect of a calibration of a gas meter sensor in accordance with an embodiment of the invention; and

Figure 14 shows the relative locations of an optical sensor and an optical emitter of a gas meter sensor in accordance with an embodiment of the present invention.

An apparatus, referred to as a gas meter sensor, according to a first embodiment of the invention will now be described.

Figure 1 shows a gas meter sensor 1 in accordance with a first embodiment of the invention. The gas meter sensor 1 comprises a sensor head 10 and a sensor control unit 60 comprising a processor and wireless transmission capability for transmitting data externally of the gas meter sensor 1.

The sensor head 10, shown in more detail in Figure 2, comprises an optical emitter 20 adjacent an optical detector 30 on one side of the sensor head 10. The optical emitter 20 and optical detector 30 in this embodiment are configured, respectively, to emit and detect infra-red radiation in particular. The sensor head 10 further comprises a magnetometer 40. A data cable 50 is provided between the sensor head 10 and the sensor control unit 60.

The optical emitter 20 and optical detector 30 may be mounted such that they are angled towards one another, as illustrated in Figure 14. In particular, the optical emitter 20 may be configured to emit optical radiation having a core component directed along a first axis while the optical detector 30 may be configured for optimal detection of optical radiation received along a second axis. The first axis may intersect the second axis such that an angle between the first axis and the second axis is 20°.

The gas meter sensor head 10 may be attached to a gas meter using an adaptor plate 100. Four possible adaptor plates 100 are shown in Figure 3. Further possible adaptor plates, not illustrated, may be envisaged. Each adaptor plate 100 comprises a gas meter sensor receiving portion 110 for receiving the gas meter sensor head 10 in one orientation. The orientation in which the gas meter sensor head 10 is received into the gas meter sensor receiving portion 110 is such that either the optical emitter and optical detector are located adjacent an aperture 120 in the adaptor plate 100 or such that an optical emitter 20 is located adjacent a first aperture 120 in the adaptor plate 100 and an optical detector 30 is located adjacent a second aperture 130 in the adaptor plate 100.

In one alternative adaptor plate 100, as shown in Figure 3 and labelled B, a pair of apertures 120, 130 is arranged such that when the gas meter sensor head 10 is received into the gas meter sensor receiving portion 110, the optical emitter 20 of the gas meter sensor head 10 is adjacent a first aperture 120 of the two apertures and the optical detector 30 of the gas meter sensor head 10 is adjacent a second aperture 130 of the two apertures. This arrangement of apertures has been found to be particularly effective for analysing rotation of a dial in a gas meter of the dial-type, as illustrated in Figure 4 and 6 (where a dial has reference numeral 500). Each of the two apertures 120,130 in this case is circular and is non-perpendicular to a main plane of the adaptor plate.

In a further alternative adaptor plate 100 of Figure 3 (labelled C), there is a single aperture 120 that is rectangular. The aperture is sized and located such that when the gas meter sensor head 10 is received into the gas meter sensor receiving portion 110, both the optical emitter 20 and the optical detector 30 of the gas meter sensor head 10 are adjacent the aperture 120. Again, the aperture 120 is non-perpendicular to a main plane of the adaptor plate. For some meters, it has been shown that an adaptor plate with a square aperture rather than a circular aperture is preferable for increased accuracy. This may be appropriate for a drum-type meter, such as that illustrated in Figure 5 (where a drum has reference numeral 600).

Each adaptor plate comprises one or more locator feet 180. These locator feet 180 are such that a surface of the adaptor plate 100 that is on an opposite side of the adaptor plate 100 from the gas meter receiving portion 110 sits proud of a surface to which the adaptor plate may come into contact. That same surface on the opposite side of the adaptor plate from the gas meter receiving portion may include an adhesive layer (not shown). The locator feet 180 therefore allow a user to slide the locator feet 180 of the adaptor plate 100 over the surface to which it is to be attached in order to position it correctly without the adhesive causing the surface of the adaptor plate to stick to the surface to which it is to be attached until such time that the user pushes the adaptor plate 100 against the surface to which it is to be attached which cases that adaptor feet 180 to deform slightly so resulting in the adhesive layer coming into contact with the surface to which it is to be attached and thereby causing the adaptor plate 100 to become fixed to the surface. In the illustrated examples, the adaptor feet extend approximately 0.3 mm from the surface to which adhesive is applied. This has been found to be sufficient to prevent the adhesive from coming into contact with the surface to which it may be attached when no pressure is applied towards that surface. However, only a small amount of pressure needs to be applied in that direction in order for the locator feet 180 to deform slightly in order for the adhesive to come into contact with the surface to which the adaptor plate 100 is to be attached.

The surface to which the adaptor plate 100 is to be attached is intended to be a face of a gas meter and the adaptor plate 100 is to be aligned by the user prior to affixing such that the aperture 120 or apertures 120, 130 align with a feature of the meter to be read. Such feature may be a rotating dial or a reflective dot on a rotating drum, as explained further below.

The adaptor plate 100 may comprise one or more identifiers to assist the consumer in deciding, in consultation with instructions, which is most appropriate adaptor plate 100 for the gas meter to which the gas meter sensor head 10 of the gas meter sensor 1 is to be attached via the adaptor plate 100. The adaptor plate 100 may also comprise indicators such as arrows to assist the consumer in orienting the adaptor plate 100 appropriately.

The gas meter sensor 1 is intended to be compatible with a wide range of different gas meters, using different techniques for displaying a reading.

Generally, imperial meters (which measure consumption in cubic feet) comprise either a dial to represent each digit (see Figure 4) or a dial for the least significant figure with more significant figures being represented by rotating drums (see Figure 6). Generally, metric meters (which measure consumption in cubic meters) comprise all rotating drums (see Figure 5), with a reflective dot at a single location on at least the rotating drum representing the least significant digit. Whatever type of meter, it is generally necessary for the gas meter sensor 1 to read only the least significant digit in order to keep track of consumption over time.

Hence, in the case of an imperial meter, the adaptor plate 100 is located such that the aperture 120 or apertures 130 are adjacent the dial showing the least significant digit, as shown in Figure 7. In the case of a metric meter, the adaptor plate 100 is located such that the aperture 120 is adjacent the drum showing the least significant digit (see Figure 8).

For every full rotation of the least significant drum 600 or dial 500, the gas meter sensor controller itself can keep count of the numbers of more significant digits (10s, 100s, 1,000s, etc.) rather than having to read the values of the drums and/or dials representing more significant digits.

Figures 10 and 11 show the gas meter sensor head 10 in various different orientations dependent upon the type of meter (metric or imperial) and the location of the least significant dial or drum relative to other moving parts (in particular, other dials or drums) in order to avoid sensitivity of the sensor 1 to moving parts other than the rotation of the least significant drum or dial.

For each available gas meter, instructions are provided with the gas meter sensor 1 regarding which adaptor plate 100 to use and how to orientate the adaptor plate 100 on the meter in order to obtain best results.

In use, once an adaptor plate 100 has been fastened to the gas meter in accordance with the instructions for the particular gas meter, the gas meter sensor head 10 is fastened to the gas meter receiving portion 110 of the adaptor plate 100. The gas meter sensor 1 then performs a calibration routine to enable the gas meter sensor able to read the particular meter to which it has been attached. Calibration may be initiated by pressing a button 65 on the control unit 60 once the sensor head 10 has been located in the adaptor plate 100 adjacent the appropriate part of the gas meter to be read. The calibration routine is intended to take account of factors such as the type of meter, the orientation of the adaptor in relation to the drum or dial to be detected, the transparency or opacity of a window of the gas meter through which the drum or dial is visible, the ambient conditions (including lighting and other magnetic fields), and other factors.

Since all gas meters are, in principle, capable of being read by optical means (for the reason that they are designed to be read by a human user reading the dials and/or drums), the gas meter sensor first performs a calibration routine to attempt to read the meter optically using the infra-red emitter and infra-red detector.

In the preferred embodiment, the infra-red sensor is configured to collect the infra-red radiation into a charge bin. The charge bin is emptied of charge at a set frequency equivalent to a first predetermined number of clock cycles of the controller. When the level of charge in the charge bin exceeds a threshold, generally but not necessarily half of the maximum capacity of the charge bin, a binary 1 is registered by the controller. A binary 1 will only register, therefore, if the charge reaches the threshold within the first predetermined number of clock cycles of the controller. In the event that the threshold is not reached by the conclusion of the first predetermined number of clock cycles, a binary 0 is registered by the controller.

The higher the reflectance, the quicker the charge bin will be filled. The quicker the charge bin is filled, the fewer the number of clock cycles are necessary to achieve a binary 1. Effectively, in this way, reflectance is measured by the number of clock cycles. In particular, a low clock cycle count for a binary 1 means high reflectance and a high clock cycle count for a binary 1 means a low reflectance.

Figure 12 shows the infra-red emitter being switched on at clock cycle 4. The infra-red sensor detects a reflection of the infra-red from the emitter and begins contributing charge to the charge bin in proportion to the amount of infra-red radiation detected. At approximately 59 clock cycles, the charge bin becomes half full and a binary 1 is registered (shown as the micro input state).

The optical calibration routine comprises first identifying the rotating feature to be detected once per rotation. In the case of an imperial meter, this is likely to be a dial needle passing a specific location on the meter (e.g. passing the printer number O’), dependent upon the positioning of the adaptor plate relative to the dial. In the case of a metric meter, this is likely to be a reflective dot present in standard metric meters at one location on the drum (e.g. within the central portion of the printed number O’). For the purpose of ease of description, whatever the feature to be detected, it is referred to herein as a reference location.

In order for the optical sensing routine of the gas meter sensor 1 to be able to be resilient to changes in ambient conditions, when the sensor 1 detects the reference location, it is helpful if the charge bin reaches half full at approximately half the first predetermined number of clock cycles of the controller.

Accordingly, in the preferred embodiment, during calibration when the gas meter sensor 1 is reading the reference location, the power at which the infra-red emitter is driven is varied until such time that the infra-red sensor provides sufficient charge to the charge bin in order to trigger a binary 1 at half the first predetermined number of clock cycles.

With reference to Figure 13, which shows the infra-red emitter power and the infra-red sensor bin value with clock count, it can be seen that the infra-red emitter drive power is varied with feedback from the infra-red sensor in order for the power at which it is driven to be honed in on a value that results in the binary 1 being registered at approximately half of the first predetermined number of clock cycles. In this way, there is room for changes in ambient conditions (such as ambient light or opacity of the gas meter window) in either direction before false sensing is likely to occur (either a false binary 1 or a false binary 0).

In the event that the calibration routine is completed successfully, the gas meter sensor may then be used in a regular optical measuring routine in order to register each time the reference point is passed and keep a count of the number of passes in order to determine an amount of gas used.

There may be circumstances in which the calibration of the optical (specifically, in the described embodiment the infra-red) sensing is unsuccessful. Possible reasons may be a misaligned sensor head, a dirty gas meter with a window having insufficient transparency, or other reasons.

In such circumstances, the magnetic sensing capability may be used, albeit that this method will only be successful for a gas meter having a magnet mounted in a rotating drum or dial. Imperial gas meters do not generally include such a magnet.

In the preferred embodiment, the magnetic sensor is a magnetometer capable of measuring magnetic field strength data for each of three dimensions, X, Y and Z.

Advantageously, this assists with the usability of the gas meter sensor with a broad range of different gas meters wherein the gas meter sensor may (perhaps for compatibility with the optical sensing capability) be located relative to the gas meter in a variety of locations.

In particular, using a magnetometer capable of measuring magnetic field strength in each of three dimensions means that the gas meter sensor head can be located in a number of different orientations and at a range of distances from a magnet which rotates with a rotating component of the gas meter.

This is in contrast to prior art reed switch magnetic sensors which require a particular position and orientation relative to the magnet. Given that reed switches are so sensitive to position and orientation, this effectively means that a universal reed switch sensor capable of self-calibration is not feasible. Rather, different sensors are required for different meters in order to ensure that the reed switches are in the appropriate location and orientation for a particular gas meter.

Calibration of the magnetic sensor involves obtaining from the magnetometer magnetic field strength data from the magnetometer and identifying any data which, during a rotation of the rotating component of the gas meter may be caused to saturate.

One technique for achieving the calibration may be to sum together the magnitudes of the field in all three dimensions to find the magnitude sum using the following calculation:

Magnitude Sum = V (X2 + Y2 + Z2)

In the event that the calibration finds this Magnitude Sum to produce a regular oscillating waveform having a single pulse then these data may be used to track rotation of the rotating component during the magnetic measuring routine.

In the event that the calibration finds this Magnitude Sum to produce a trace that is not a regular oscillating waveform having a single pulse then either one or more of the dimensions of field may be dismissed or a weighted sum algorithm may be employed in order to emphasise those axes providing unsaturated data and deemphasise those providing saturated data, whilst not eliminating them altogether.

Such a technique may involve calculation of an adapted Magnitude Sum using the following calculation:

Modified Magnitude Sum = V {(aX)2 + (bY)2 + (cZ)2} where a, b and c may be variables obtained during the magnetic calibration routine on the basis of measurements of the field strength.

Magnitude sums need not be limited to the specific examples shown here. For example, the magnitude sum might be obtained by the following calculations:

Alternative Magnitude Sum = [ (X3 + Y3 + Z3) ]"3

Alternative Modified Magnitude Sum = [ {(aX)3 + (bY)3 + (cZ)3} ]"3

By processing the data so as to refine it into the form of a substantially regular oscillating waveform having a single pulse (for each rotation of the magnet within the meter) it may be used to track rotation of the drum in order to provide meaningful gas usage data.

Regardless of the way in which the data is obtained by the gas meter sensor e.g. whether optically or magnetically, the data may then be transmitted wirelessly to a server or other processing capability which stores and processes the data further. In this way, a user can have their gas usage, as measured by the gas meter sensor, plotted against time. This may enable a user to see how gas consumption varies with time of day. Further data may be obtained by the server or other processor such as weather events average temperature for the locality. In this way a user may be able to observe how usage compares with ambient temperatures and possible other weather events.

The processed data may be made available to a user from the server, perhaps via a webpage or application on a PC, tablet, smartphone or other device. There may be security features in place in order to prevent unauthorised parties from accessing the data.

While the specific embodiment has focused on a device having both optical (infra-red) and magnetic sensing capabilities, other alternative embodiments fall within the scope of the present disclosure.

For example, an alternative embodiment may have only the optical sensing capabilities (active infra-red sensing, in the preferred embodiment) and none of the magnetic sensing capabilities. Since all meters can be read optically, such a device is still considered to have wide applicability to a broadest possible range of current gas meter designs.

Furthermore, optical sensing is not limited to active infra-red sensing as described in the preferred embodiment. For example, optical sensing may comprise active or passive sensing of any of infra-red, visible spectrum or ultra-violet radiation. Indeed, optical sensing may involve any form of transducer for detecting optical radiation of any form and converting it into a value related to the intensity of detected optical radiation. Other forms of optical transducer might include a light dependent resistor.

Furthermore, while the optical measuring of the specific embodiment collects charge in bins over a specific number of clock cycles, it will be appreciated that other optical sensing methods and optical calibration techniques may be appropriate and would still fall within the scope of the claim. With regard to the optical calibration technique, the broad concept is that of auto gain control which, in the specific embodiment is achieved through varying the power of the emitter until the receiver triggers a binary 1 at an average sensitivity. Other, alternative auto gain control techniques may be used. Furthermore, even in case of the described auto gain control technique, it may be that the intensity of the light emitted is varied by means other than the power at which the emitter is driven. For example, the emitter may be driven at constant power but the light emitted may be varied by perhaps some form of filtering. Many other alternatives may be envisages and would fall within the scope of the claims.

The disclosure includes a range of features that give rise to a universal gas meter sensor that is applicable to a wide range of current gas meters. It is perfectly possible, and within the scope of the claims, to provide some but not all of the described features in a single product. For example, in the case of a gas meter sensor intended only for use with gas meters having no magnet, there may be no benefit in providing any magnetic sensing capability. Such an alternative, along with many others, falls within the scope of the claims.

Unless specially recited as being essential to include a particular plurality of features in combination, the description is not to be interpreted as implying that the plurality features would be required in order to fall within the scope of the claim.

The present application discloses subject matter in accordance with the following numbered clauses:

Clause A1. A gas meter sensor for detecting movement of a rotating element of a gas meter, the gas meter sensor comprising first and second sensors, wherein the first sensor is an optical sensor and the second sensor is a magnetic sensor.

Clause A2. The gas meter sensor of clause A1 wherein the gas meter sensor further comprises a controller configured to perform either or both of an optical measuring routine and a magnetic measuring routine.

Clause A3. The gas meter sensor of clause A2 wherein the optical sensor comprises an emitter and a detector and wherein the detector is configured to detect a reflection of radiation emitted by the emitter.

Clause A4. The gas meter sensor of clause A3 wherein the optical emitter is configured to emit optical radiation having a core component directed along a first axis and the optical detector is configured for optimal detection of optical radiation received along a second axis, wherein the first axis intersects the second axis.

Clause A5. The gas meter sensor of clause A4 wherein the first axis intersects the second axis such that an angle between the first axis and the second axis is between 5° and 35°, preferably between 15° and 25°, most preferably 20°.

Clause A6. The gas meter sensor of any of clauses A3 to A5 wherein the optical sensor comprises an infra-red emitter and an infra-red detector and wherein the infra-red detector is configured to detect a reflection of infra-red radiation emitted by the infra-red emitter.

Clause A7. The gas meter sensor of any of clauses A3 to A5 wherein the optical sensor comprises a visible light emitter and visible light detector and wherein the visible light detector is configured to detect a reflection of visible light emitted by the visible light emitter.

Clause A8. The gas meter sensor of clause A3 wherein the optical sensor is configured to yield a value that is proportional to radiation detected by the optical sensor.

Clause A9. The gas meter sensor of clause A8 wherein the optical sensor is configured to obtain the value cumulatively over a first predetermined time and to clear the value following the conclusion of the first predetermined time.

Clause A10. The gas meter sensor of clause A9 wherein a binary 1 is returned if the value reaches a threshold prior to the conclusion of the first predetermined time and a binary 0 is returned if the value is below the threshold at the conclusion of the first predetermined time.

Clause A11. The gas meter sensor of clause A10 wherein the controller is configured to perform an optical calibration routine to determine an intensity of radiation to be output by the emitter during the optical measuring routine, the optical calibration routine comprising: identifying a reference reflective condition indicative of a reflection of emitted radiation from a first portion of a gas meter; during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned.

Clause A12. The gas meter sensor of clause A11 wherein the controller is configured to vary the intensity of radiation of the emitter by varying the power at which the emitter is driven.

Clause A13. The gas meter sensor of clause A11 or clause A12 wherein the optical sensor is configured: (a) to obtain the value cumulatively over a first predetermined time and to clear the value following the conclusion of the first predetermined time; (b) to return a binary 1 if the value reaches the threshold prior to the conclusion of the first predetermined time and to return a binary 0 if the value is below the threshold at the conclusion of the first predetermined time; (c) to perform the calibration routine wherein the average intensity is defined as an intensity at which a binary 1 is returned at a second predetermined time, wherein the second predetermined time is approximately half the first predetermined time.

Clause A14. The gas meter sensor of clause A13 wherein the optical measuring routine involves driving the optical emitter at the reference intensity.

Clause A15. The gas meter sensor of clause A8 or any clause dependent upon clause A8 wherein the value is an electric charge derived from the optical sensor.

Clause A16. The gas meter sensor of clause A9 or any clause dependent upon clause A9 wherein the first predetermined time is equivalent to a first predetermined number of clock cycles.

Clause A17. The gas meter sensor of any of preceding clause wherein the magnetic sensor is a magnetometer configured to detect strength of a magnetic field in three dimensions.

Clause A18. The gas meter sensor of clause A17 wherein the controller is configured to receive data from the magnetometer representative of magnetic field strength in three dimensions and thereby measure rotation of a magnet mounted on a rotating needle or drum in a gas meter.

Clause A19. The gas meter sensor of clause A18 when dependent directly or indirectly on clause A2 wherein the controller is configured to perform a magnetic calibration routine, the magnetic calibration routine comprising: identifying if data representative of magnetic field strength of one or two of the three dimensions results in saturation of the magnetometer in those one or two dimensions during rotation of a magnet in the gas meter; and eliminating data for those one or two dimensions for the purposes of assessing rotation of the magnet during the magnetic measuring routine.

Clause A20. A gas meter sensor for detecting movement of a rotating element of a gas meter, the gas meter sensor comprising: an optical sensor having an optical controller, an optical emitter and an optical detector configured to detect a reflection of optical radiation emitted by the optical emitter, wherein the optical sensor is configured: (a) to generate a value that is proportional to radiation detected by the optical sensor; (b) to return a binary 1 if the value reaches a threshold; (c) to perform a calibration routine to determine an intensity of radiation to be output by the emitter during an optical measuring routine, the calibration routine comprising: (i) identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached in use; (ii) during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned; and (d) to drive the optical emitter at the reference intensity in order to determine a rate of movement of a rotating element in a gas meter to which the sensor may be attached in use.

Clause A21. The gas meter sensor of clause A20 wherein the controller is configured to vary the intensity of radiation of the emitter by varying the power at which the emitter is driven.

Clause A22. The gas meter sensor of clause A20 or clause A21 wherein the optical sensor is configured: (a) to obtain the value cumulatively over a first predetermined time and to clear the value following the conclusion of the first predetermined time; (b) to return a binary 1 if the value reaches the threshold prior to the conclusion of the first predetermined time and to return a binary 0 if the value is below the threshold at the conclusion of the first predetermined time; (c) to perform the calibration routine wherein the average power obtained at step (iii) is defined as a power at which a binary 1 is returned at a second predetermined time, wherein the second predetermined time is approximately half the first predetermined time.

Clause A23. The gas meter sensor of any of clauses A20 to A22 wherein the value is an electric charge derived from the optical sensor.

Clause A24. The gas meter sensor of any of clauses A20 to A23 wherein the first predetermined time is equivalent to a first predetermined number of clock cycles.

Clause A25. The gas meter sensor of any of clauses A20 to A24 wherein the optical emitter is configured to emit optical radiation having a core component directed along a first axis and the optical detector is configured for optimal detection of optical radiation received along a second axis, wherein the first axis intersects the second axis.

Clause A26. The gas meter sensor of clause A25 wherein the first axis intersects the second axis such that an angle between the first axis and the second axis is between 5° and 35°, preferably between 15° and 25°, most preferably 20°.

Clause A27. The gas meter sensor of any of clauses A20 to A26 wherein the optical sensor comprises an infra-red emitter and an infra-red detector and wherein the infra-red detector is configured to detect a reflection of infra-red radiation emitted by the infra-red emitter.

Clause A28. The gas meter sensor of any of clauses A20 to A26 wherein the optical sensor comprises a visible light emitter and visible light detector and wherein the visible light detector is configured to detect a reflection of visible light emitted by the visible light emitter.

Clause A29. The gas meter sensor of any of clauses A20 to A28 further comprising a magnetic sensor for detecting movement of a rotating element of a gas meter.

Clause A30. The gas meter sensor of clause A29 wherein the magnetic sensor comprises a magnetometer configured to detect strength of a magnetic field in three dimensions.

Clause A31. The gas meter sensor of any preceding clause wherein the sensor further comprises a transmitter for providing data generated by the sensor to an external device.

Clause A32. The gas meter sensor of clause A31 wherein the transmitter is a WiFi transmitter.

Clause A33. A mounting bracket suitable for mounting a gas meter sensor of any preceding clause, wherein the bracket comprises: a gas meter sensor receiving portion for attaching at least a part of the gas meter sensor to the bracket; a first aperture adjacent the gas meter sensor receiving portion; and a fixing element for fixing the mounting bracket to a gas meter such that aperture is located adjacent a rotating element in the gas meter.

Clause A34. The mounting bracket of clause A33 wherein the fixing element comprises a self-adhesive layer and wherein the mounting bracket further comprises resilient alignment feet having a first configuration and a second configuration wherein: in the first configuration, the alignment feet are configured to maintain a gap between the self-adhesive layer and a gas meter to which the mounting bracket may be attached; and in the second configuration, the alignment feet are configured to enable contact between the self-adhesive layer and a gas meter to which the mounting bracket may be attached.

Clause A35. The mounting bracket of clause A34 wherein the alignment feet are deformable in order to achieve a transition from the first configuration to the second configuration.

Clause A36. The mounting bracket of any of clauses A33 to A35 wherein the gas meter sensor receiving portion is located relative to the first aperture such that a gas meter sensor of any of clauses A1 to A31 received into the gas meter sensor receiving portion is aligned such that the an optical sensor of gas meter sensor is adjacent the first aperture to allow optical radiation to pass through the aperture to and/or from the optical sensor.

Clause A37. The mounting bracket of any of clauses A33 to A36 wherein the first aperture of the mounting bracket is located in a planar region of the bracket and wherein a bore of the aperture is non-perpendicular to the planar region of the bracket.

Clause A38. The mounting bracket of clause A37 further comprising a second aperture adjacent the first aperture, wherein the gas meter sensor receiving portion is located relative to the first and second apertures such that an optical emitter and an optical detector of a gas meter sensor of any of clauses A3 to A32 received into the gas meter sensor receiving portion are aligned with the first and the second apertures, respectively, in order to minimise interference of emitted and reflected radiation.

Clause A39. The mounting bracket of any of clauses A33 to A38 wherein the aperture comprises means for focusing optical radiation.

Clause A40. The mounting bracket of clause A39 wherein the means for focusing optical radiation is a light tunnel.

Clause A41. A kit of parts comprising the gas meter sensor of any of clauses A1 to A32 and a mounting bracket of any of clauses A33 to A40.

Clause A42. The kit of parts of clause A41 comprising a plurality of mounting brackets, wherein each mounting bracket of the plurality of mounting brackets is configured to be compatible with one or more specific gas meters.

Clause A43. The kit of parts of clause A42 wherein at least one of the mounting plates comprises a single aperture and at least one of the mounting plates comprises a pair of apertures.

Clause A44. A method of calibrating a gas meter sensor of the kind defined in clause A3 or clause A20 or any clause dependent upon clause A3 or clause A20, the method comprising: (i) identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached; (ii) during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned.

Clause A45. The method of clause A44 wherein the gas meter sensor is configured: (a) to obtain the value cumulatively over a first predetermined time and to clear the value following the conclusion of the first predetermined time; (b) to return a binary 1 if the value reaches the threshold prior to the conclusion of the first predetermined time and to return a binary 0 if the value is below the threshold at the conclusion of the first predetermined time; and wherein the average power is defined as a power at which a binary 1 is returned at a second predetermined time, wherein the second predetermined time is approximately half the first predetermined time.

Clause A46. The method of clause A44 or clause A45 wherein the step of varying the power comprises using a successive approximation to approach the reference power value.

Clause A47. The gas meter sensor of any of clauses A44 to A46 wherein the value is an electric charge derived from the optical sensor.

Clause A48. The gas meter sensor of any of clauses A44 to A47 wherein the first predetermined time is equivalent to a first predetermined number of clock cycles.

Clause A49. The method of any of clauses A44 to A48 for calibrating a gas meter sensor of the kind defined in clause A3 or A29 or any clause dependent upon clause A3 or A29, the method comprising: obtaining from the magnetic sensor a value, X, Y and Z, representative of a measured magnetic field strength in each of three spatial dimensions; and weighting subsequent values for any of X, Y or Z in the event that said value causes the magnetic sensor to be saturated, in order to reduce an influence of any saturated value on an overall sensor calculation.

Clause A50. The method of any of clauses A44 to A49 for calibrating a gas meter sensor of the kind defined in clause A3 or A29 or any clause dependent upon clause A3 or A29, the method comprising: obtaining from the magnetic sensor a value, X, Y and Z, representative of a measured magnetic field strength in each of three spatial dimensions; and eliminating subsequent values for any of X, Y or Z in the event that said value causes the magnetic sensor to be saturated.

Clause A51. The method of clause A49 or clause A50 further comprising: calculating a magnitude sum of the non-excluded values by squaring each value, adding the results together and taking a square root of the total.

Clause A52. The method of clause A51 further comprising: analysing a variation of the magnitude sum with time in order to determine a rate of movement of a rotating element in a gas meter to which the sensor may be attached in use.

Clause A53. A method of calibrating a gas meter sensor of the kind defined in clause A2 or any clause dependent upon clause A2 and wherein the magnetic sensor comprises a magnetometer capable of detecting strength of a magnetic field in three dimensions, the method comprising: identifying if data representative of magnetic field strength of one or two of the three dimensions results in saturation of the magnetometer in those one or two dimensions during rotation of a magnet in the gas meter; and weighting subsequent values for any of X, Y or Z in the event that said value causes the magnetic sensor to be saturated, in order to reduce an influence of any saturated value on an overall sensor calculation

Clause A54. A method of calibrating a gas meter sensor of the kind defined in clause A2 or any clause dependent upon clause A2 and wherein the magnetic sensor comprises a magnetometer capable of detecting strength of a magnetic field in three dimensions, the method comprising: identifying if data representative of magnetic field strength of one or two of the three dimensions results in saturation of the magnetometer in those one or two dimensions during rotation of a magnet in the gas meter; and eliminating data for those one or two dimensions for the purposes of assessing rotation of the magnet during the magnetic measuring routine.

Claims

CLAIMS:

1. A gas meter sensor for detecting movement of a rotating element of a gas meter, the gas meter sensor comprising: an optical sensor having an optical controller, an optical emitter and an optical detector configured to detect a reflection of optical radiation emitted by the optical emitter, wherein the optical sensor is configured: (a) to generate a value that is proportional to radiation detected by the optical sensor; (b) to return a binary 1 if the value reaches a threshold; (c) to perform a calibration routine to determine an intensity of radiation to be output by the emitter during an optical measuring routine, the calibration routine comprising: (i) identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached in use; (ii) during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned; and (d) to drive the optical emitter at the reference intensity in order to determine a rate of movement of a rotating element in a gas meter to which the sensor may be attached in use.

2. The gas meter sensor of claim 1 wherein the controller is configured to vary the intensity of radiation of the emitter by varying the power at which the emitter is driven.

3. The gas meter sensor of claim 1 or claim 2 wherein the optical sensor is configured: (a) to obtain the value cumulatively over a first predetermined time and to clear the value following the conclusion of the first predetermined time; (b) to return a binary 1 if the value reaches the threshold prior to the conclusion of the first predetermined time and to return a binary 0 if the value is below the threshold at the conclusion of the first predetermined time; (c) to perform the calibration routine wherein the average power obtained at step (iii) is defined as a power at which a binary 1 is returned at a second predetermined time, wherein the second predetermined time is approximately half the first predetermined time.

4. The gas meter sensor of any of claims 1 to 3 wherein the value is an electric charge derived from the optical sensor.

5. The gas meter sensor of any of claims 1 to 4 wherein the first predetermined time is equivalent to a first predetermined number of clock cycles.

6. The gas meter sensor of any of claims 1 to 5 wherein the optical emitter is configured to emit optical radiation having a core component directed along a first axis and the optical detector is configured for optimal detection of optical radiation received along a second axis, wherein the first axis intersects the second axis.

7. The gas meter sensor of claim 6 wherein the first axis intersects the second axis such that an angle between the first axis and the second axis is between 5° and 35°, preferably between 15° and 25°, most preferably 20°.

8. The gas meter sensor of any of claims 1 to 7 wherein the optical sensor comprises an infra-red emitter and an infra-red detector and wherein the infra-red detector is configured to detect a reflection of infra-red radiation emitted by the infra-red emitter.

9. The gas meter sensor of any of claims 1 to 7 wherein the optical sensor comprises a visible light emitter and visible light detector and wherein the visible light detector is configured to detect a reflection of visible light emitted by the visible light emitter.

10. The gas meter sensor of any of claims 1 to 9 further comprising a magnetic sensor for detecting movement of a rotating element of a gas meter.

11. The gas meter sensor of claim 10 wherein the magnetic sensor comprises a magnetometer configured to detect strength of a magnetic field in three dimensions.

12. The gas meter sensor of any preceding claim wherein the sensor further comprises a transmitter for providing data generated by the sensor to an external device.

13. The gas meter sensor of claim 12 wherein the transmitter is a WiFi transmitter.

14. A method of calibrating a gas meter sensor of the kind defined in any preceding claim, the method comprising: (i) identifying a reference reflection condition indicative of a reflection of emitted radiation from a first portion of a gas meter to which the sensor may be attached; (ii) during the reference reflection condition, varying the intensity of radiation of the emitter in order to determine a reference intensity, the reference intensity being an average intensity at which a binary 1 is returned.

15. The method of claim 14 wherein the gas meter sensor is configured: (a) to obtain the value cumulatively over a first predetermined time and to clear the value following the conclusion of the first predetermined time; (b) to return a binary 1 if the value reaches the threshold prior to the conclusion of the first predetermined time and to return a binary 0 if the value is below the threshold at the conclusion of the first predetermined time; and wherein the average power is defined as a power at which a binary 1 is returned at a second predetermined time, wherein the second predetermined time is approximately half the first predetermined time.

16. The method of claim 14 or claim 15 wherein the step of varying the power comprises using a successive approximation to approach the reference power value.

17. The gas meter sensor of any of claims 14 to 16 wherein the value is an electric charge derived from the optical sensor.

18. The gas meter sensor of any of claims 14 to 17 wherein the first predetermined time is equivalent to a first predetermined number of clock cycles.

19. The method of any of claims 14 to 18 for calibrating a gas meter sensor of the kind defined in any of claims 1 to 13, the method comprising: obtaining from the magnetic sensor a value, X, Y and Z, representative of a measured magnetic field strength in each of three spatial dimensions; and weighting subsequent values for any of X, Y or Z in the event that said value causes the magnetic sensor to be saturated, in order to reduce an influence of any saturated value on an overall sensor calculation.

20. The method of any of claims 14 to 19 for calibrating a gas meter sensor of the kind defined in any of claims 1 to 13, the method comprising: obtaining from the magnetic sensor a value, X, Y and Z, representative of a measured magnetic field strength in each of three spatial dimensions; and eliminating subsequent values for any of X, Y or Z in the event that said value causes the magnetic sensor to be saturated.

21. The method of claim 19 or claim 20 further comprising: calculating a magnitude sum of the non-excluded values by squaring each value, adding the results together and taking a square root of the total.

22. The method of claim 21 further comprising: analysing a variation of the magnitude sum with time in order to determine a rate of movement of a rotating element in a gas meter to which the sensor may be attached in use.