GB2488375A - Appliance safety system - Google Patents

Abstract

The invention provides a monitoring system arranged to interrupt a power supply to an appliance, such as a boiler, in the event of detecting the presence of a hazardous substance, such as carbon monoxide, smoke, or natural gas. The power supply may be interrupted in response to an instantaneous measurement of a hazardous substance exceeding a threshold value. Alternatively, the power supply may be interrupted in response to a persistent presence of a hazardous substance exceeding a threshold value. In a further embodiment, the monitoring system may also be arranged to interrupt the power supply to the appliance when a service is due, and to resume power to the appliance when servicing has been carried out.

Description

I Apliance Safety System 3 The present invention relates to improvements to apparatus and methods in safety 4 systems for appliances. In particular, embodiments of the present invention include apparatus and methods for detecting the presence of a hazardous substance and cutting 6 off power to a related appliance from the mains supply in response.

8 Background to the invention

GB2346225A describes a device for shutting down a gas appliance when servicing 11 becomes due. This device ensures that gas appliances are serviced as required by law 12 and as required to ensure the safety of any occupants of the property in which they are 13 installed.

However, it is also desired to protect and potentially save the lives and/or improve the 16 health of occupants of properties in which said appliances are used. Conventional carbon 17 monoxide (CO) detectors produce an alarm when a predetermined level of CO is detected 18 in the atmosphere. However, such detectors have inherent disadvantages, as do other 19 similar detectors such as smoke detectors.

2 It is therefore an object of embodiments of the present invention to provide an apparatus 3 and a method that obviates and/or mitigates one or more disadvantages of the prior art.

Particularly, it is an object of embodiments of the present invention to disable an appliance 6 in response to detecting the presence of a hazardous substance.

1 Summary of the invention

3 According to a first aspect of the invention, there is provided a monitoring system for an 4 appliance comprising: a control module; 6 at least one sensor module configured to detect the presence of at least one 7 hazardous substance; and 8 a communications link between the control module and the one or more sensor 9 modules; wherein the control module is configured to control a power supply to the appliance 11 responsive to the at least one sensor module detecting the presence of a hazardous 12 substance.

14 The hazardous substance may be selected from the group comprising carbon monoxide (CO), smoke and domestic or natural gas. Accordingly, the at least one sensor module 16 may comprise a CO detector, smoke detector and/or gas detector.

18 Most preferably, the control module comprises a switch unit connected in-line between the 19 appliance and a mains supply and operable to disconnect the appliance from the mains supply. The mains supply may be a domestic, commercial or industrial electrical and/or 21 gas supply.

23 Preferably, the control module is configured to switch off the appliance in response to 24 receiving a signal from the one or more sensor modules indicative of the presence of a hazardous substance. Alternatively, or additionally, the control module is configured to 26 switch off the appliance responsive to determining that an instantaneous measurement of 27 a hazardous substance exceeds a threshold value.

29 Alternatively, or additionally, the control module is configured to switch off the appliance responsive to determining that a persistent presence of a hazardous substance exceeds a 31 predetermined exposure threshold value.

33 A typical use of this function would be to monitor persistent, low levels of carbon monoxide 34 which otherwise would not be at a sufficient concentration to trigger a conventional CO detector. While such concentrations may not be harmful to health if present for a brief 1 period of time, it is believed that chronic exposure to such lower levels can cause health 2 problems and are indicative of a poorly functioning or inadequately maintained gas 3 appliance which should be investigated.

Preferably, the control module is configured to record the amount of the hazardous 6 substance present as a function of time. Optionally, the amount is recorded continuously.

7 Alternatively, the amount is recorded periodically; in which case preferably the peak 8 amount of the hazardous substance recorded within the period is recorded.

This will assist, for example, in forensic analysis and diagnosis when environmental 11 conditions (such as the abovementioned chronic CO exposure) are relevant.

13 Preferably, the control module further comprises a power supply. The power supply may 14 be a battery, in which case it is preferably a rechargeable battery. The battery may be recharged from the mains supply.

17 Preferably, the communications link comprises a wireless communications protocol. Most 18 preferably, the communications link comprises a radio frequency (RF) communications 19 protocol; in which case preferably each of the control module and at least one sensor module further comprises a radio frequency transceiver.

22 Optionally, the system further comprises a service module, configured to interrogate the 23 control module and/or the at least one sensor module via the communications link or a 24 further communications link. The further communications link is preferably wireless, for example RF, but may be wired; in which case a corresponding interface is provided.

27 Preferably, the service module is adapted to reset the control module so as to resume a 28 previously interrupted power supply to an appliance. Optionally, the service module is 29 configured to store a date and time associated with said resumption. Preferably, the service module is configured to receive and store measurements of the levels of 31 hazardous substance detected by the sensor module.

33 Preferably, the control module, sensor module, and/or service module are configured to 34 generate and/or store one or more of; an installation date of the appliance, a date of a next service due date of the appliance, a unique identifier associated with the appliance or the 1 relevant module. This information may be stored in volatile or non-volatile, removable or 2 integral, memory.

4 Advantageously, the control module, sensor module, and/or service module are configured to generate and/or store one or more of; an elapsed time since the last communication 6 with another module, calibration information, alarm levels (such as predetermined 7 threshold values).

9 The system may be arranged and configured so as to switch on an extractor fan should air quality drop below a threshold.

12 Optionally, the system is further adapted to interrupt power to the appliance when 13 servicing becomes due and resume power to the appliance when servicing has been 14 effected.

16 According to a second aspect of the invention, there is provided a control module, capable 17 of interrupting a power supply to an appliance, adapted for use in the monitoring system of 18 the first aspect.

According to a third aspect of the present invention, there is provided a sensor module, 21 capable of detecting the presence of one or more hazardous substances, adapted for use 22 in the monitoring system of the first aspect.

24 According to a fourth aspect of the present invention, there is provided a service module, configured to interrogate a control module and/or a sensor module, adapted for use in the 26 monitoring system of the first aspect.

28 Embodiments of the second to fourth aspects of the invention may include one or more 29 features of the first aspect of the invention or its embodiments, or vice versa.

31 According to a fifth aspect of the invention, there is provided a method of controlling a 32 power supply to an appliance comprising the steps of: 33 monitoring for the presence of at least one hazardous substance; and 34 interrupting the power supply to the appliance responsive to detecting the presence of a hazardous substance.

2 Optionally, the method comprises the additional steps of: 3 interrupting the power supply to the appliance when servicing becomes due; and 4 resuming power to the appliance when servicing has been effected.

6 Embodiments of the fifth aspect of the invention may include one or more features 7 corresponding to features of the first to fourth aspects of the invention or its embodiments, 8 orvice versa.

1 Brief description of the drawings

3 There will now be described, by way of example only, various embodiments of the 4 invention with reference to the drawings, of which: 6 Figure 1 illustrates, in schematic form, a monitoring system in accordance with an aspect 7 of the present invention; 9 Figure 2 illustrates, in schematic form, a control module of a monitoring system such as illustrated in Figure 1, in accordance with an aspect of the present invention; 12 Figure 3 illustrates, in schematic form, a sensor module of a monitoring system such as 13 illustrated in Figure 1, in accordance with an aspect of the present invention; Figure 4 illustrates, in schematic form, a service module of a monitoring system such as 16 illustrated in Figure 1, in accordance with an aspect of the present invention; and 18 Figure 5 illustrates, in schematic form, operation of a monitoring system such as illustrated 19 in Figure 1, in accordance with an aspect of the present invention.

1 Detailed description of preferred embodiments

3 An embodiment of the present invention will now be described in the context of a domestic 4 boiler; it will be readily apparent from a reading of the following description that the system and associated methods are equally applicable and readily transferable to alternative 6 applications.

8 Indicated generally by reference numeral 101 is a monitoring system for an appliance, in 9 this case a boiler 109. The system 101 can be seen to comprise a control module 103 positioned in-line between a mains supply 107 and the boiler 109. In this way, the control 11 module 103 is able to (if necessary) interrupt the power supply to the boiler 109, in effect 12 switching it off.

14 Connected, via wireless communication links, to the control module 103 are a number of sensor modules 105a, 105b, 105c. In this example, the sensor module 105a comprises a 16 carbon monoxide (CO) sensor, sensor module 105b comprises a smoke detector and 17 sensor module 105c comprises a gas detector (to detect domestic/natural gas). The 18 wireless communication links provide a means for the detectors to transmit information to 19 the control module 103.

21 Figure 2 illustrates further detail of the control module itself. It can be seen to comprise an 22 in-line switch 115 to cut off power to the boiler when required. The switch 115 is controlled 23 by a suitably programmed microcontroller 113 which is able to receive data from sensor 24 modules 105 via RF transceiver 119 (sensor modules have corresponding RF transceivers, see 131 in Figure 3). Based on this data, the microcontroller 113 makes a 26 determination as to whether power should be cut off to the boiler.

28 For example, if an instantaneous measurement of carbon monoxide exceeds a 29 predetermined threshold, the appliance will be switched off. Optionally, speaker 120 may output an audible alarm as well. Another condition that will result in the appliance being 31 switched off will be if the CO level is beneath the same predetermined level threshold but 32 an exposure level (i.e. instantaneous level integrated over a predetermined time period) 33 threshold is exceeded. Thus both sudden and chronic exposures to harmful CO can be 34 prevented.

1 The control module 103 is allocated a unique identifier (indicated generally by reference 2 numeral I 02a). This may be stored, along with data from detectors (also with their own 3 unique identifiers, see 102b in Figure 3) for interrogation and/or extraction by a servicing 4 module 111. Thus all data, communications etc. can be coded such that only authorised or linked devices can exchange data. This ensures that signals from non-linked sensors 6 cannot interfere with the system (and vice versa). The IDs are hard-coded and therefore 7 cannot be changed.

9 In addition to the unique ID, the control module comprises a clock 117. Similarly, the sensor module (see Figure 3) comprises a clock 127. This enables date-stamping of data 11 sent and/or received. The control module clock 117 may be used to calibrate the sensor 12 module clock 127, or vice versa.

14 A portion of non-volatile memory 121 is provided within the control module. This memory, as well as storing the program instructions that enable operation of the system, stores 16 configuration parameters, and optionally other data such as the date and time of the next 17 service, warning levels, actions to take when error, warning or fault conditions are 18 identified and the like.

A power supply 118 is also provided; the control unit is preferably powered independently 21 of mains supply but may be powered by mains supply with a battery backup. Thus 22 receiving and recording of data from the sensor modules may continue uninterrupted in the 23 event of failure of the mains supply to the control unit 103.

Figure 3 presents further detail of an exemplary sensor module 105. Similar to the control 26 module 103, the sensor module 105 comprises a microcontroller 123 and an RF 27 transceiver 131. A detector component 133 is employed to detect (for example) carbon 28 monoxide, smoke or natural/domestic gas. This monitoring takes place continuously and 29 measured data stored in memory 125. in this example, a maximum level within a predetermined period is determined and transmitted to the control unit 103 when the 31 period expires. Accordingly, transmission is periodic which conserves power (supplied by 32 battery 135).

34 The sensor module 105 stores (in non-volatile memory 127) a number of pieces of information. For example, thresholds and predetermined values on which alarm or error 1 determinations may be made; the time period since last communication before a warning 2 condition or an error condition arises, the action required in either case, the action required 3 if an alarm condition is met (e.g. sound an alarm and shut off the boiler), calibration 4 information, logging intervals and desired logging space.

6 The sensor module 105 also stores a number of alarm levels, such as threshold levels (as 7 above), flags for whether thresholds are upper or lower, trigger count for the threshold 8 levels, samples to check, and alert state of the remote sensor when the threshold level or 9 alarm condition is met.

11 It is particularly advantageous if the control module 103 does not need to interpret any 12 data received from the sensor module 105; for example, the sensor module 105 may 13 provide an indication to the control module 103 that an alarm condition (or a warning 14 condition) is met and the control module 103 need only react to that in the predetermined way (stored in the control and/or sensor module memory). Accordingly, new types of 16 sensor can be incorporated without necessarily updating the control module 103 firmware.

18 Note that the sensor module 105 is also provided with a speaker 130 to allow an audible 19 alarm to be emitted, as is the case with conventional sensors. In fact, the sensor module 105 may be such a conventional sensor modified for the additional functionality required to 21 implement the invention; in which case the skilled person will be able to readily implement 22 the necessary changes from the present disclosure.

24 Figure 4 provides detail of an exemplary service module 111. It is envisaged that such a device may be employed by servicing engineers or investigators to interrogate the control 26 module 103 or sensor module 105, or simply to reset the control module and (in the event 27 of interruption of power thereto) reinstate power to the boiler 107.

29 Similarly to the above, the service module 111 comprises a microcontroller 137 and an RF transceiver 139. This allows the service module 111 to communicate with the sensor 31 module 105 and/or control module 103. The service module may be used during 32 installation, configuration, and/or resetting of the control module 103.

34 The service module 111 is provided with a graphical user interface 147 to allow a user to interact with it. This may include such features as an LCD display (with LED backlight) 1 and a membrane keypad. In addition, the service module 111 is also powered by a battery 2 145. The battery 145 is advantageously provided with an interface (e.g. USB 146) to 3 enable recharging; of course, the USB interface 146 may also be employed to interface 4 with a PC or the like to download extracted data for further analysis.

6 A memory card interface 143 is also provided, capable of receiving and reading/writing 7 data to/from a memory card 144 (e.g. SD card). Thus, information extracted from the 8 control module 103 or sensor module 105 can be stored on removeable media for backup 9 storage etc. 11 The service module 111 is preferably a hand held unit, and the particular embodiment 12 described herein lends itself to such compact construction. Thus when an event has 13 occurred to cause the boiler to be switched off (e.g. gas leak or CO exposure limit 14 exceeded) the boiler can be switched on again once the cause of the leak or breach has been remedied.

17 Figure 5 provides a flow chart 201 showing the general mode of operation of an 18 embodiment of the present invention. Initially, a CO exposure is detected 203 in which 19 case power to the boiler is cut off 205 (as described above). In addition to switching off the boiler, an alarm is sounded 207 to provide audible warning (not only that the boiler is 21 off but that there is a hazardous substance present and remedial action is required).

22 Subsequently, repairs are carried out 209 by a suitably qualified person, after which the 23 system can be reset and power to the boiler reinstated 211.

A number of optional additional steps/features are disclosed. For example, a "snooze" 26 function similar to that present in digital alarm clocks is provided 215, by which the audible 27 alarm can be silenced (and, optionally, resumed after a predetermined time period has 28 elapsed).

Furthermore, additional functionality can be included such as a system shut down in the 31 event of a service due date being exceeded without action. In addition to the automatic 32 suspension of operation of the boiler occasioned by a CO leak, the system may determine 33 that a service is overdue and as a result switch off the boiler. Temporary user override 34 may be possible by means of the "snooze" functionality, however reset 211 may only take 1 place once the boiler has been properly service 209 (and optionally the monitoring system 2 recalibrated 217).

4 Some objectives met by embodiments of the invention herein described are to protect and save the lives and improve the health of residents of properties where gas appliances are 6 used, and to provide forensic facilities to assist in investigations where a gas appliance is 7 suspected to be contributory to the death or ill health of any occupants of the property in 8 which they are installed The invention provides a link between one or more gas or smoke detectors and a base 11 unit which can record regular detection levels and events from each of those detectors.

12 Possible detector types are for carbon monoxide (00), natural gas and smoke but the 13 technology is not restrictive and any detector capable of transmitting relevant data (or 14 adaptable to transmit said data) can be used.

16 The base unit can record level and event information from each detector over a 17 predetermined time period (e.g. 12 months) and this information can be extracted from the 18 base unit by a link to a servicing unit and optionally onto a PC for further analysis (e.g. a 19 graph can be produced showing the CO levels from each detector over a period of interest).

22 In addition, if any detector enters an alarm condition (each detector will operate as a 23 stand-alone detector), this alarm event can be transmitted to and recorded by the base 24 unit. The base unit may also incorporate a battery maintained real-time clock which is used to timestamp all detector level information and events and to keep track of the 26 amount of time since any connected equipment was serviced.

28 The base unit can optionally be connected to an appliance (e.g. a domestic gas boiler) in 29 such a way that the mains power supply to that appliance can be deliberately interrupted by the base unit in certain conditions. Typical uses of this functionality are to; disconnect 31 the appliance from the mains supply if the CO level from any one detector exceeds a safe 32 limit (or the CO detector indicates an alarm event), and optionally ensure that the 33 appliance is not used beyond its maximum service interval.

1 The base unit can also monitor maximum and rolling average levels from each detector 2 and can be set to issue an alarm and interrupt the mains supply to any connected 3 appliance in the event of one or both of these levels exceeding some predefined limit. The 4 rolling average may be the mean level recorded for each detector over a predefined time window (e.g. 48 hours) and the maximum may be the maximum level recorded over that 6 same period. A typical use of this function would be to monitor persistent, low levels of 7 carbon monoxide which otherwise would not be at a sufficient concentration to trigger any 8 CO detector. While such concentrations may not be harmful to health if present for a brief 9 period of time, it is believed that chronic exposure to such lower levels can cause health problems and are indicative of a poorly functioning or inadequately maintained gas 11 appliance which should then be investigated before CO concentration reaches a 12 dangerous level.

14 Finally, the ability of the base unit to record levels and events for a period of at least 12 months allows the technology to be used for forensic purposes when investigating possible 16 causes of fire or poisoning.

18 This technology both complements and enhances current technologies. There are many 19 other applications of the technology as the appliance need not be a domestic gas appliance and the skilled person will readily be able to apply the invention described herein 21 to any mains powered appliance that may need to be switched on or off when certain 22 conditions as reported by remote sensors/detectors of any kind are recorded. For 23 example, the base unit could be configured to switch on an extractor fan should air quality 24 drop below a predefined threshold.

26 The invention provides a monitoring system and methods for interrupting a power supply 27 to an appliance, such as a boiler, in the event of detecting the presence of a hazardous 28 substance (such as carbon monoxide). A preferred embodiment of the invention interrupts 29 the power supply responsive to determining that an exposure level, rather than just an instantaneous level, exceeds a predetermined threshold. Corresponding control modules, 31 sensor modules and servicing modules are also provided to put the invention into effect.

33 The foregoing description of the invention has been presented for the purposes of 34 illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. The described embodiments were chosen and described in 1 order to best explain the principles of the invention and its practical application to thereby 2 enable others skilled in the art to best utilise the invention in various embodiments and 3 with various modifications as are suited to the particular use contemplated. Therefore, 4 further modifications or improvements may be incorporated without departing from the scope of the invention as defined by the appended claims.