GB2372130A

GB2372130A - Monitoring system for a gas-fired boiler providing warning of a sensed condition approaching or in excess of a predetermined limit

Info

Publication number: GB2372130A
Application number: GB0126101A
Authority: GB
Inventors: John H Devine; Michael Richford; Michael Donnelly
Original assignee: MULHERON MAUREEN
Current assignee: MULHERON MAUREEN
Priority date: 2000-10-31
Filing date: 2001-10-31
Publication date: 2002-08-14
Anticipated expiration: 2021-10-31
Also published as: GB0126101D0; GB0026538D0; GB2372130B

Abstract

Monitoring system 22 having at least one sensor for monitoring equipment such as a gas-fired boiler 14 in a heating system 10 and providing a warning to indicate a sensed value approaching or in excess of a predetermined limit value. The sensor may distinguish between operation and non-operation of the equipment 14 to monitor its cumulative use and provide a warning via the system 22 to indicate maintenance must be undertaken. The warning signal may comprise a plural-stage signal to signify approach and excess of the predetermined limit value. The sensor may be used to detect excess combustion products or fuel gas, and the monitoring system may include a means for transferring information to and from the property to a remote location to provide a remote warning of sensed conditions. The monitoring system may be provided as a kit of parts to enable retrofitting to a pre-existing central heating system.

Description

Monitoring Systems This invention relates to monitoring systems, and relates particularly but not exclusively to property maintenance monitoring systems for monitoring imminent service needs of a gas-fired boiler in a domestic central heating system, and other aspects of property maintenance. More particularly, the system includes a suitable telecommunications means to transfer information to and from the property to a remote location.

In the United Kingdom, many large urban and suburban areas are designated as smokeless zones and are also supplied with mains-distributed natural gas.

Consequently, gas-fired domestic central heating is widespread in owner-occupied dwellings. However, despite the advantages of gas-fired domestic central heating, such heating systems are less likely to be installed in tenant-occupied dwellings, particularly if the tenants are not affluent and/or elderly.

Moreover, tenants commonly rely on their landlord for

safety checks, efficiency checks, and routine maintenance where such heating systems are utilised, and consequently these essential precautions are more likely to be overlooked than in owner-occupied dwellings where there is an immediate personal interest of the person/people resident in the dwelling.

Proposals for large-scale social remediation by widespread installation of gas-fired central heating in tenant-occupied dwellings thus raise problematic issues arising from the combination of tenant dependency, landlord liability, and large numbers of geographically distribution locations to which access may not always be readily available for checks and maintenance of heating equipment. Accordingly it is an object of the invention to provide a monitoring system which, as applied to gas-fired domestic central heating boilers, obviates or mitigates the risk of checks and/or maintenance of the boiler being overlooked.

According to a first aspect of the present invention there is provided a monitoring system for monitoring at least one performance characteristic of controllably operable equipment, the monitoring system comprising at least one sensor responsive to said at least one performance characteristic to deliver a sensor output dependent on said at least one performance characteristic, the monitoring system being coupled to receive the sensor output and to

respond to sensed imminent or immediate excess of a predetermined limit to emit a warning signal.

Where the performance characteristic comprises functional operation of the equipment (as distinct from quiescence or stasis), the sensor is preferably such as to distinguish between operation and nonoperation, and the monitoring system is adapted to monitor the cumulative duration of equipment operation, said predetermined limit comprising a predetermined limit of operational duration after which safe and/or efficient operation depends upon checks upon and/or maintenance of the equipment having been undertaken.

The warning signal may comprise a plural-stage signal, for example a preliminary warning signal to signify the approach of the predetermined limit, and an alarm signal to signify the achievement or excess of the predetermined limit.

Where the performance characteristic comprises safe operation of the equipment with operation of the equipment while at least one equipment parameter exceeds a respective limit representing instantaneously unsafe operation, the sensor is preferably such as to sense the exceeding of said respective limit and the monitoring system is such as to respond substantially immediately with an alarm signal and/or with a control signal causing operation of the equipment to terminate forthwith.

Where the performance characteristic comprises efficient operation of the equipment with operation of the equipment while at least one equipment parameter exceeds a respective limit representing instantaneously inefficient operation, the sensor is preferably such as to sense the exceeding of said respective limit and the monitoring system is such as to respond to said respective limit being exceeded for a predetermined time to emit a preliminary warning signal or an alarm signal or a shutdown signal, or a signal advancing the time at which a duration-based"maintenance-due"signal is emitted.

According to a second aspect of the present invention there is provided a monitoring system for monitoring at least one performance characteristic of a gasfired central heating boiler, the monitoring system comprising at least one sensor responsive to said at least one performance characteristic to deliver a sensor output dependent on said at least one performance characteristic, the monitoring system being coupled to receive the sensor output and to respond to sensed imminent or immediate excess of a predetermined limit to emit a warning signal.

Where the performance characteristic of the boiler is gas-combusting operation of the boiler (as distinct from having only a pilot light ignited, or being completely shut down), the sensor is preferably such as to distinguish between gas-combusting operation

and non-operation, and the monitoring system is adapted to monitor the cumulative duration of gas combusting operation, said predetermined limit comprising a predetermined limit of gas-combusting operational duration after which safe and/or efficient operation of the boiler depends upon checks upon and/or maintenance of the boiler having been undertaken. (Such checks and/or maintenance may be those which are necessary or desirable for technical reasons, or may be checks and/or maintenance mandated by statute (s) and/or by statutory regulation (s)).

The warning signal of this second aspect of the present invention may comprise a plural-stage signal, for example a preliminary warning signal (e. g. the lighting of a warning lamp or sign) to signify the approach of the deadline for checks/maintenance (eg the stage where no more than four weeks of normal operation are possible without checking/maintenance), an alarm (e. g. an intermittent or continuous audible alarm) to signify the necessity for an immediate appointment for the attendance of an inspector/maintenance person (eg the stage where no more than two weeks of normal operation are possible without checking/maintenance), and finally a shutdown signal at the expiry of the predetermined period of normal operation in order to prevent continued operation of the boiler (unless the monitoring system has meanwhile been reset by the inspector/maintenance person).

Where the performance characteristic comprises safe operation of the boiler with operation of the boiler while at least one boiler parameter exceeds a respective parameter representing instantaneously unsafe operation, the sensor is preferably such as to sense the exceeding of said respective limit and the monitoring system is such as to respond substantially immediately with an alarm signal and/or with a control signal causing immediate shutdown of the boiler. Said at least one boiler parameter may comprise boiler temperature such that the monitoring system shuts down the boiler either substantially immediately upon the sensing of over-temperature, or upon a sensed over-temperature being sustained for a predetermined period of time. Said at least one boiler parameter may additionally or alternatively comprise leak-tightness, since neither combustion products nor fuel gas should be present outside the boiler casing and inside the dwelling in detectable quantities, ie the sensor is sensitive to methane, carbon monoxide, and excessive levels of carbon dioxide, the sensor being located outside the boiler casing but inside the dwelling (the presence of combustion products in the open air outside the dwelling being disregarded).

Where the performance characteristic comprises efficient operation of the boiler with operation of the boiler while at least one boiler parameter exceeds a respective limit representing instantaneously inefficient operation, the sensor is

preferably such as to sense the exceeding of said respective limit and to said respective limit and the monitoring system is such as to respond to said respective limit being exceeded for a predetermined time to emit a preliminary warning signal, or a signal advancing the time at which a duration-based "maintenance-due"signal is emitted. The predetermined time for which said respective limit must be exceeded before the monitoring system responds allows for transient conditions to be disregarded (e. g. at cold start-up). The boiler parameter may be combustion efficiency, and the sensor may be responsive to the presence in the boiler exhaust of substances whose presence in excessive levels indicates inefficient combustion (e. g. substances such as methane, carbon (soot), and carbon monoxide). The sensor (or another sensor) may be responsive to the clogging of one or more gas burner nozzles and/or the fouling of flame-to-water heat exchange surfaces (e. g. with soot and/or clinker).

In all aspects of the invention, the monitoring system may be coupled by suitable telecommunications means to a location remote from the boiler or other equipment whose performance is being monitored whereby to deliver a remote repetition of the warning signal when emitted, the remote location being, for example, inspectors'headquarters, a maintenance depot, or other central location where a custodian or other responsible person (or organisation) is

located, the remote location potentially being respectively coupled to a plurality of differently sited monitoring systems.

According to a third aspect of the present invention there is provided a central heating system for a dwelling, the central heating system comprising a gas-fired heat-generating boiler, distribution and utilisation means for distributing and utilising boiler-generated heat within the dwelling, and a monitoring system according to the second aspect of the present invention, the at least one sensor of the monitoring system being disposed to respond to at least one selected performance characteristic of said gas-fired heat-generating boiler.

According to a fourth aspect of the present invention there is provided a kit of parts for retrofitting a boiler performance monitoring system to a preexisting central heating system in a dwelling, said pre-existing central heating system comprising a gasfired heat-generating boiler together with distribution and utilisation means for distributing and utilising boiler-generated heat within the dwelling, the kit of parts comprising a monitoring system according to the second aspect of the present invention, the monitoring system comprising at least one sensor adapted to be coupled to said boiler to respond to a selected performance characteristic of the boiler and to deliver a sensor output dependent on said selected performance characteristic, the

monitoring system being adapted to be coupled to receive the sensor output when the kit of parts is installed and thereupon to respond to sensed imminent or immediate excess of a predetermined limit to emit a warning signal.

Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings wherein: Fig. 1 is a block schematic diagram of an embodiment of a gas-fired central heating system incorporating a boiler monitoring system in accordance with the invention; Fig. 2 is a schematic representation of the contents of one of the blocks depicted in Fig. 1; Fig. 3 is a schematic representation of the exterior of the embodiment of the boiler monitoring system; and Fig. 4 is a schematic representation of the monitoring system including the telecommunication means to and from a remote location.

Referring first to Fig. 1, this is an overall block schematic view of a central heating system 10 for use in a dwelling 12. The central heating system 10 comprises a gas-fired heat-generating boiler 14 (known per se) whose useful thermal output is

delivered to distribution and utilisation means 16 with the dwelling 12, e. g. the boiler 14 heats water which is pumped to one or more radiators and/or hot water taps (or hot water storage tanks) and/or showers, etc. The boiler 14 is subject to the overall control of a central heating control unit 18 in the form of a conventional time switch capable of switching the boiler 14 on twice per day for selected intervals of time programmable by the occupant of the dwelling and/or by the landlord of the dwelling.

When not switched on by the time switch control unit 18, the boiler 14 is inoperative and quiescent, ie the boiler is not in gas-burning and heat-generating mode (other than possibly for the trivial effects of a boiler pilot light remaining ignited). Apart from the overall off/on control effected by the control unit 18, fine control of the boiler 14 is effected by conventional control means (not shown) within the boiler 14, e. g. a thermostat for over-temperature protection, and a possible gas throttle operated by water flowrate sensing means responding to variable opening of a hot water tap forming part of the distribution and utilisation means 16. Electrical power for operation of the central heating system 10 is obtained from a conventional 240 volt, 50 Hertz single-phase mains supply 20 within the dwelling 12.

(Such electrical power is not for heat-generating purposes, but for powering control and auxiliary functions, e. g. the time switch 18 and a water pump (not shown) circulating boiler-heated water through radiator (s) forming part of the distribution and

utilisation means 16). For simplicity, a supply of fuel gas (e. g. natural methane) for the boiler 14 is omitted from the drawings.

Even if operation of the boiler 14 is always within preset limits of one or more performance characteristics, it is mandatory or desirable for the boiler 14 to be inspected and maintained after a predetermined extent of usage. A boiler which is operated for (say) sixteen hours per day will be more heavily used within a given calendar period than an otherwise identical boiler which is operated for only (say) two hours per day. Thus an inspection and maintenance schedule based solely upon calendar intervals will impose unnecessarily frequent inspections on lightly used boilers and/or insufficiently frequent inspections of heavily used boilers, with consequent inefficiency and/or safety hazards. Accordingly, it is proposed that in accordance with the invention, the central heating system 10 incorporate a monitoring system 22 to monitor the cumulative operation of the boiler 14, and to emit distinct forms of warning signal as the time for inspection and maintenance of the boiler 14 is approached and then reached. Service intervals may be monitored by means of a real time clock.

The location of the monitoring system 22 between the control unit 18 and the boiler 14 is depicted in Fig.

1, while internal details of the monitoring system 22

are schematically depicted in Fig. 2 to which reference will now be made.

Within the monitoring system 22, a transformer 24 receives power from the mains supply 20 via the time switch 18 and delivers a twelve-volt output 26 which serves to power a monitoring control circuit 28 which may be in the form of a programmable microprocessor or a dedicated special-purpose integrated circuit.

(Details of the function of the circuit 28 will be given subsequently). The mains supply 20 continues beyond the transformer 24 and passes through a relay 30 which is controllably operable (as will subsequently be detailed) to switch mains power off and on, and thereby controllably switch the boiler 14 off and on since operation of the boiler 14 is controllable by the presence or absence of mains power on the output 32 of the relay 30.

The monitoring control circuit 28 functions to measure the cumulative time for which the mains output 34 of the time switch 18 is on, and hence the cumulative time for which the boiler 14 is nominally operative (actual operation of the boiler 14 instantaneously depending on additional control (s) such as e. g. a thermostat etc). The control circuit 28 is programmed or preset with a time limit (e. g.

500 hours, 1000 hours or any other appropriate duration) after which the boiler 14 cannot be allowed to continue operation without first being subjected to inspection and maintenance. The monitoring

control circuit 28 thus acts as a sensor of boiler operation, combined with limit monitoring and warning functions which will now be detailed.

As the sensed cumulative duration of boiler operation reaches a first threshold in advance of the preset time limit (e. g. four weeks in advance), the control circuit 28 switches on a first warning lamp 36 to provide an externally visible indication as a preliminary warning.

As the sensed cumulative duration of boiler operation subsequently reaches a second threshold in advance of the preset time limit (e. g. two weeks in advance), the control circuit 28 switches on a second warning lamp 38 which is combined with a sounder (not shown separately), e. g. a buzzer, to provide a final warning which is externally visible and externally audible.

If the boiler 14 is, at this stage, subjected to inspection and maintenance, the monitoring system 22 is reset, such as to extinguish the lamps 36 and 38 and to silence the buzzer or other form of sounder, and simultaneously to reset the control circuit 28 to set the measure of sensed cumulative duration of boiler operation at zero.

However, if the boiler 14 is not subjected to inspection prior to the preset time limit (and the monitoring system 22 is not concomitantly reset),

continued operation of the boiler 14 up to the preset time limit is sensed by the circuit 28 which consequently lights an alarm light 40 and simultaneously causes the relay 30 to open, thereby depriving the boiler 14 of electrical power essential for continued operation of the boiler 14 and causing the boiler 14 immediately to shut down. Operation of the boiler 14 cannot recommence until inspection and maintenance of the boiler, and resetting of the monitoring system 22 as previously detailed.

The monitoring system 22 thus functions to sense the boiler performance characteristic consisting of the actual duration of the operation of the boiler 14 (as distinct from mere observation of the calendar interval since last inspection, which does not distinguish between operation and non-operation), and to emit warning signals as the operational time limit is first approached and then reached, with the additional safety function of enforced shutdown upon the time limit being reached. A prototype form of the monitoring system 22 is photographically illustrated in Fig. 3.

The monitoring system 22 may be adapted to sense and monitor additional or alternative performance characteristics, such as the possible leakage of toxic fumes from the boiler 14 into the dwelling 12, overtemperature, combustion efficiency, etc. , and to emit a warning signal or shutdown signal according to circumstances and preset criteria. According to the

selected performance characteristics, the monitoring system would employ one or more suitably located sensors responsive to one or more of carbon dioxide, carbon monoxide, carbon (soot), methane (or other fuel gas), temperature, flame colour, etc.

The warning lamps 36,38 and 40 may be simple LEDs (light-emitting diodes) or may be other suitable forms of lamp; in particular, lamps which are large and brighter then LEDs may be adopted for monitoring systems installed in the dwellings of persons with impaired sight. Similarly, the sounder may be appropriately substituted in dwellings occupied by persons with impaired hearing.

The monitoring system 22 detailed above relies upon warnings emitted visibly and/or audibly to the occupant (s) of the dwelling 12, and then upon the warned occupant (s) to notify the relevant person or organisation responsible for inspection and maintenance. However, referring to Fig. 4, greater reliability of notification of the requirement for inspection/maintenance could be achieved if such notification could be made automatically, and to this end the monitoring system 22 could incorporate a modem or other suitable form of telecommunications equipment such as radio transmission 110 or other cable-less device such as GSM or blue tooth equipment or a fixed line connection 112 or transmission through a third party device 114 such as via the Internet, for transmitting data to and from a remote

location 120, triggered by emission of a warning signal from the circuit 28 to transmit a notification of the warning to the relevant person or organisation (e. g. the landlord of the dwelling, a concierge, or the administrative offices of a local authority or housing association).

The system can be used to log data relating to the performance characteristics, including data relating to measurement of usage and flow of gas, electricity and other utilities, such as water and telecommunications.

The monitoring system 22 includes appropriate means to provide a failsafe function which operates to control the boiler 14, such that, if any conditions which may be undesired or hazardous exist in the boiler 14, the system will make adjustments to counteract these conditions.

The system includes a software element which facilitates the management of the data which has been logged, the software being used on site and at the remote location 120. The data is stored in an appropriate database and the information can be used to make decisions as to the timings of service intervals for example.

An audible signal and/or a visual display are included in the system to monitor the efficiency of the boiler by monitoring the output from the

performance characteristics, and any other relevant data.

Information from the system can be output on site to a user, or automatically, as well as at the remote location 120. Also, information can be input to the system either on site or from the remote location 120, by a user or automatically.

The monitoring system 22 can be incorporated into new central hearing installations as built, or the monitoring system 22 can be supplied as a kit for retrofitting to a pre-existing central heating installation which lacks such a monitoring system, or which has a monitoring system that requires to be replaced.

The monitoring system of the invention can be adapted to monitoring one or more performance characteristics of equipment other than domestic central heating systems.

Other modifications and variations can be adopted without departing from the scope of the invention.

Claims

CLAIMS 1. A monitoring system for monitoring at least one performance characteristic of controllably operable equipment, the monitoring system comprising at least one sensor responsive to said at least one performance characteristic to deliver a sensor output dependent on said at least one performance characteristic, the monitoring system being coupled to receive the sensor output and to respond to sensed imminent or immediate excess of a predetermined limit to emit a warning signal.
2. A monitoring system as claimed in Claim 1, wherein the controllably operable equipment is a gas-fired central heating boiler.
3. A monitoring system as claimed in either one of Claims 1 or 2, wherein the sensor is such as to distinguish between operation and non-operation of the equipment, and the monitoring system is adapted to monitor the cumulative duration of equipment operation, said predetermined limit comprising a predetermined limit of operational duration after which safe and/or efficient operation depends upon checks upon and/or maintenance of the equipment having been undertaken.
4. A monitoring system as claimed in any preceding claim, wherein the performance characteristic comprises safe operation of the equipment, operation of the equipment while at least one equipment parameter exceeds a respective limit representing instantaneously unsafe operation, and wherein the sensor senses the exceeding of said respective limit and the monitoring system responds substantially immediately with an alarm signal.
5. A monitoring system as claimed in Claim 4, wherein said at least one equipment parameter comprises equipment temperature.
6. A monitoring system as claimed in Claim 4, wherein said at least one equipment parameter comprises leak-tightness.
7. A monitoring system as claimed in Claim 6, wherein the sensor is sensitive to methane, carbon monoxide, and excessive levels of carbon dioxide, the sensor being located outside the equipment.
8. A monitoring system as claimed in any preceding claim, wherein the performance characteristic comprises efficient operation of the equipment, operation of the equipment while at least one equipment parameter exceeds a respective limit representing instantaneously inefficient operation, and wherein the sensor senses the

exceeding of said respective limit and the monitoring system responds to said respective limit being exceeded for a predetermined time to emit a preliminary warning signal or an alarm signal, or a signal advancing the time at which a duration-based"maintenance-due"signal is emitted.
9. A monitoring system as claimed in any preceding claim, wherein the performance characteristic of the equipment is gas-combusting operation of the equipment, the sensor distinguishing between gas-combusting operation and non operation of the equipment, and wherein the monitoring system is adapted to monitor the cumulative duration of gas-combusting operation, said predetermined limit comprising a predetermined limit of gas-combusting operational duration after which safe and/or efficient operation of the equipment depends upon checks upon and/or maintenance of the boiler having been undertaken.
10. A monitoring system as claimed in any preceding claim, wherein the warning signal comprises a plural-stage signal, the plural-stage signal including a preliminary warning signal to signify the approach of the predetermined limit, and an alarm signal to signify the achievement or excess of the predetermined limit.
11. A monitoring system as claimed in Claim 10, wherein the preliminary warning signal signifies the approach of the deadline for inspection and/or maintenance of the equipment, and the alarm signal signifies the necessity for immediate inspection and/or maintenance of the equipment.
12. A monitoring system as claimed in either Claim 10 or Claim 11, wherein the preliminary warning signal includes the lighting of a warning lamp or sign.
13. A monitoring system as claimed in any one of Claims 10 to 12, wherein the alarm signal includes an intermittent or continuous audible alarm.
14. A monitoring system as claimed in Claim 6, wherein the predetermined time for which said respective limit must be exceeded before the monitoring system responds allows for transient conditions to be disregarded.
15. A monitoring system as claimed in Claim 6 when dependent on Claim 2, wherein the boiler parameter is combustion efficiency, and the sensor is responsive to the presence in the boiler exhaust of substances whose presence in excessive levels indicates inefficient combustion.
16. A monitoring system as claimed in Claim 15, wherein the sensor is responsive to the clogging of one or more gas burner nozzles and/or the fouling of flame-to-water heat exchange surfaces.
17. A monitoring system as claimed in any preceding claim, wherein the monitoring system is coupled by suitable telecommunications means to a location remote from the equipment whose performance is being monitored whereby to deliver a remote repetition of the warning signal when emitted.
18. A monitoring system as claimed in Claim 17, wherein the remote location is an inspectors' headquarters, a maintenance depot, or other central location where a custodian or other responsible person (or organisation) is located, the remote location potentially being respectively coupled to a plurality of differently sited monitoring systems.
19. A central heating system for a dwelling, the central heating system comprising a gas-fired heat-generating boiler, distribution and utilisation means for distributing and utilising boiler-generated heat within the dwelling, and a monitoring system according to Claims 2 to 18, the at least one sensor of the monitoring system being disposed to respond to at least one selected performance

characteristic of said gas-fired heatgenerating boiler.
20. A kit of parts for retrofitting a boiler performance monitoring system to a pre-existing central heating system in a dwelling, said pre existing central heating system comprising a gas-fired heat-generating boiler together with distribution and utilisation means for distributing and utilising boiler-generated heat within the dwelling, the kit of parts comprising a monitoring system according to Claims 2 to 18, the monitoring system comprising at least one sensor adapted to be coupled to said boiler to respond to a selected performance characteristic of the boiler and to deliver a sensor output dependent on said selected performance characteristic, the monitoring system being adapted to be coupled to receive the sensor output when the kit of parts is installed and thereupon to respond to sensed imminent or immediate excess of a predetermined limit to emit a warning signal.
21. A monitoring system for monitoring at least one performance characteristic of controllably operable equipment, the monitoring system being substantially as hereinbefore described with reference to the accompanying drawings.
22. A central heating system for a dwelling, the central heating system being substantially as

hereinbefore described with reference to the accompanying drawings.
23. A kit of parts for retrofitting a boiler performance monitoring system to a pre-existing central heating system in a dwelling, the kit of parts being substantially as hereinbefore described with reference to the accompanying drawings.