WO2019122889A1

WO2019122889A1 - Monitor for underground infrastructure

Info

Publication number: WO2019122889A1
Application number: PCT/GB2018/053709
Authority: WO
Inventors: Edward Klinger; Ian Courtney; Stephen JEFFREYS
Original assignee: CNIGUARD Ltd
Current assignee: CNIGUARD Ltd
Priority date: 2017-12-20
Filing date: 2018-12-20
Publication date: 2019-06-27
Anticipated expiration: 2020-06-20
Also published as: GB201804336D0; GB201721439D0; GB2569664A

Abstract

A monitoring device module for a utility vault access cover is disclosed. The module comprises at least one environmental sensor for monitoring the environment in the utility vault, a communications module for transmitting data to a receiver, the communications module having a radio antenna, at least one inner container, and a housing for receiving the sensor, the communications module and the inner container. The or each inner container comprises a chamber for receiving a power source for the module, and at least part of a side wall of the or each inner container defines a space within the housing providing a low-attenuation pathway for the propagation of radio signals from the radio antenna, with the pathway extending from the radio antenna towards the top of the housing.

Description

MONITOR FOR UNDERGROUND INFRASTRUCTURE

FIELD OF THE INVENTION

The present invention relates to a monitor for underground infrastructure. In particular, but not exclusively, the invention relates to a device for monitoring the environment in a utility vault that is housed in, mounted to or otherwise integrated with an access cover or manhole cover of the vault.

BACKGROUND TO THE INVENTION

Utility vaults, also known as manholes, utility boxes, cable chambers, inspection chambers, access chambers and so on, are underground chambers that house utility infrastructure such as electrical supply cables and equipment, switchgear, telecommunications equipment, and supply pipes for natural gas, water and steam.

Utility vaults can usually be accessed from street level by way of an access opening that is closed by a removable cover or hatch. Most utility vaults are fabricated as pre-cast concrete units or are constructed on site from concrete or brick. However, utility vaults made from plastics materials are also available.

The access cover or hatch, often referred to as a manhole cover, is usually installed flush with the roadway or pavement (sidewalk) and is of sufficient strength to withstand vehicle and pedestrian traffic. A typical manhole cover is of a metal or high-strength plastics material and may be vented or solid. The manhole cover may be shaped to fit snugly in a corresponding frame that is recessed into the roadway. The manhole cover may include sockets, eyes or other formations for engagement of one or more lifting tools, allowing the manhole cover to be lifted for access to the vault. One or more locking devices may be included to prevent unauthorised access to the vault.

The manhole cover may be attached to the frame on one side by hinges to form a hatch or, more commonly, the manhole cover may be entirely removable from the frame. Removable manhole covers are typically circular, square or rectangular, whereas hinged covers typically have at least one straight edge.

The size, shape and use of utility vaults can vary considerably, from small units with a volume of less than 1 cubic metre, for housing a relatively small number of connectors, switches or valves, up to very large units with volumes of 60 cubic metres or more, capable of housing large electrical equipment such as transformers.

Various faults and problems can occur in utility vaults which, in certain circumstances, can present a risk to public safety. For example, aged, faulty or damaged electrical supply cables can cause electrical short-circuits that may eventually result in fire or explosion. Flarmful gaseous products of burning or smouldering cables can include carbon monoxide, carbon dioxide, acetylene, methane, and polycyclic aromatic hydrocarbons, creating a toxic environment within the vault. An increase in pressure in the vault can eventually cause the cover or hatch to be violently propelled into the air. To combat this problem, covers are increasingly provided with vents to allow gases and smoke to escape, avoiding a build-up in pressure.

Another potential problem is that stray voltages within the vault due to cable or equipment faults can result in a substantial electrical potential being presented at street level if the cover or hatch is metal, posing a risk of electrocution.

These and other problems can be exacerbated by the challenging environment within the vault. The temperature within vaults can vary significantly, from around -20°C or less in winter conditions up to around 105°C or more in vaults carrying steam pipes. Also, flooding of the vault and the wash-off of road salt into the vault environment are relatively common occurrences. Such flooding is more likely where vented manhole covers are used, although it is still a problem with solid covers and hatches, which are often imperfectly sealed. The combination of salt and moisture substantially increases the risk of short circuits and arcing within the vault.

For these reasons, frequent manual inspection of utility vaults is desirable, so that any developing problems can be identified and rectified to minimise the safety risk. However, the frequency of manual inspections is limited by practical considerations due to the very large number of utility vaults (over 250,000 vaults are in service in New York City alone), the geographic spread of the vaults, and the relative inaccessibility of some vaults. As a result, the time between manual inspections may be long enough for faults to arise and develop into a serious condition before they can be identified.

Against that background, it would be desirable to provide apparatus for remotely and automatically monitoring the environment within a utility vault and for alerting engineers to developing problems within the utility vault.

It would also be desirable to provide monitoring apparatus that can be easily installed irrespective of the nature and size of the utility vault.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, a monitoring device module for a utility vault access cover is provided. The module comprises:

at least one environmental sensor for monitoring the environment in the utility vault;

a communications module for transmitting data to a receiver, the communications module having a radio antenna;

at least one inner container; and

a housing for receiving the sensor, the communications module and the inner container, the housing comprising a base and a top opposite the base;

wherein the or each inner container comprises a chamber for receiving a power source for the module;

and wherein at least part of a side wall of the or each inner container defines a space within the housing providing a low-attenuation pathway for the propagation of radio signals from the radio antenna, the pathway extending from the radio antenna towards the top of the housing. With this arrangement, a self-contained monitoring apparatus is provided that can be easily installed in substantially any type of utility vault. Furthermore, transmission of data from the module to a receiver located remotely from the utility vault can be optimised, even when a relatively large volume of the module is occupied by the power source for the module. In this way, the power consumption of the module can be minimised, and the distance between the module and the receiver can be maximised.

The pathway provided by the space is low attenuation in the sense that the pathway is free from components and materials that would act to substantially attenuate the propagation of radio signals. Preferably, therefore, the or each inner container does not intersect the space. Instead, the pathway extends adjacent to the part of the side wall of the inner container that defines the space. Said another way, the pathway extends at least partially alongside the inner container. Most preferably, the space is an air-filled cavity.

The or each inner container may be formed from a metallic or ceramic material. In one example, the or each inner container is formed from stainless steel. In this way, mechanical support and environmental protection can be provided for the power source. By virtue of the low-attenuation pathway provided by the space, the material of the or each inner container does not appreciably interfere with the transmission of radio signals from the antenna.

The housing is preferably formed from a non-metallic material, such as a plastics material. In this way, the housing does not substantially attenuate the radio signals from the antenna as they pass from the antenna through the housing to a receiver located remotely from the utility vault.

Because the low-attenuation pathway extends from the radio antenna towards the top of the housing, when the module is installed in a utility vault access cover with the top of the housing uppermost, the pathway is oriented to allow radio signals to propagate readily from the antenna upwards and out of the utility vault. The housing may comprise a side wall that extends upwardly from the base to enclose an interior of the housing. Preferably, the module comprises a lid arranged to form a seal against the side wall to close the top of the housing. The lid is preferably of a plastics material, again to avoid attenuation of the radio signal.

The or each inner container may be supported by the base of the housing. In this case, the environmental sensor, the communications module and the radio antenna may all be housed in the space. Alternatively, the side wall of the housing may comprise one or more support elements for supporting the or each inner container such that the or each inner container is spaced from the base of the housing. In this way, an additional chamber is provided within the housing, within which one or more of the environmental sensor, the communications module and the radio antenna may be housed. Preferably, however, the radio antenna is disposed in or extends into the space.

The housing preferably comprises a port for allowing gas exchange between the environment outside the housing and the interior of the housing. In this way, the environmental sensor can be protectively housed within the housing yet can still monitor the environment within the utility vault. The port may be arranged to prevent water ingress from the exterior into the interior of the housing. For example, the port may comprise a micropermeable membrane that allows gas flow through the port and prevents water ingress through the port. With this arrangement, the module is resistant to water ingress for example due to flooding of the utility vault or high levels of rainwater.

The or each inner container may comprise an inner side wall and an outer side wall defining the chamber therebetween, and the space may be defined at least in part by the inner side wall of the or each container. Preferably, the or each inner side wall and the or each outer side wall are substantially tubular or part-tubular.

In one embodiment, the or each inner side wall and the or each outer side wall are tubular such that the space is cylindrical and the or each chamber is annular. In this way, a plurality of power sources, such as battery cells, can be disposed in the annular chamber, leaving the central cylindrical space clear to provide the low- attenuation pathway. The or each inner container may comprise a base, with the or each side wall of the inner container being upstanding from the base.

The or each inner container may comprise an open top providing access to the chamber, and the bottom of the chamber may be closed, for example so that the chamber is leak-proof.

The at least one environmental sensor may include a gas sensor, preferably a carbon monoxide detector. It has been determined that the presence of high levels of carbon monoxide can be indicative of fault conditions within the vault.

The at least one environmental sensor may include a temperature sensor, a humidity sensor and/or a stray voltage detector.

The device may comprise an electrical contact providing an input for the stray voltage detector. The electrical contact may be disposed on the housing and arranged to contact the access cover in use. In this way, stray voltages on the access cover can be monitored.

The power source preferably comprises one or more battery cells. More preferably, the power source comprises one or more battery packs, each pack including a plurality of battery cells. The battery cells and/or the battery packs may be wrapped in a fire retardant material, such as a ceramic wool material, to reduce the risk of a fire in the utility vault spreading to the battery cells.

In a second aspect of the invention, a utility vault access cover is provided. The access cover comprises a monitoring device module according to the first aspect of the invention, and a receptacle for receiving the monitoring device module, the receptacle being disposed on an underside of the access cover such that, in use, the module is exposed to an internal environment of the utility vault.

Preferably, an aperture is provided in the access cover between the receptacle and an upper side of the access cover to provide a low-attenuation pathway for the propagation of radio waves from the monitoring device module through the access cover. The aperture may be closed by a cap comprising a low-attenuation material, such as a composite plastics material.

Also described is a monitoring device for a utility vault that is adapted to be carried by, mounted to or retained in an access cover of the utility vault, as well as an access cover for a utility vault that carries or retains a monitoring device.

By mounting the monitoring device in the access cover, it is possible to install the monitoring device with minimal disruption to the vault itself. In many cases, it may not be necessary to enter the vault during installation, so that the operation can be performed above ground.

Also described is a self-contained monitoring device module. The monitoring device module may comprise a battery pack or other power source, a processor, a carbon monoxide sensor, and a communications module for transmitting data from the monitoring device module to a receiver. The monitoring device module may comprise a temperature sensor, a humidity sensor and/or a stray voltage sensor. The monitoring device module may comprise a memory and the processor may be configured to write sensor data to the memory.

The communications module may comprise a cellular modem and/or a mesh network modem.

Also described is a monitoring device module comprising an outer housing for containing the components of the monitoring device module. The outer housing is designed to prevent water ingress, for example during flooding of the vault. Accordingly, the outer housing may include a port arranged to allow gas to enter the interior of the housing to reach a gas sensor disposed within the housing, but which prevents the ingress of water during flood conditions. The port may for example comprise an aperture that is covered by a microporous membrane. The port may be disposed on an underside of the outer housing, so that the port faces into the interior of the utility vault when the monitoring device module is mounted to the access cover. The top side of the outer housing may be provided with a lid or cover that forms a watertight seal against a wall of the outer housing.

Also described is a monitoring device module comprising an outer housing and an inner container received within the outer housing. The inner container may be adapted to receive one or more battery packs of the monitoring device module. The inner container may comprise a sleeve, preferably an annular sleeve, having an outer chamber for receiving the or each battery pack and a central opening. The outer chamber is preferably closed at its bottom end to form a leak-proof chamber for the battery packs. The central opening may be open at its top and bottom ends and may be arranged to accommodate a radio aerial of the monitoring device module. With this arrangement, the inner container does not appreciably attenuate radio signals transmitted and received by the aerial. The outer housing may be of a first material, preferably a plastics material such as a thermoplastic polyester resin. The first material is preferably a low-attenuation material so that radio signals can propagate readily through the outer housing. The inner container may be of a second material, preferably a metal material, such as stainless steel. When the outer housing includes a lid, the lid is preferably also of the first material.

Preferably, the or each battery pack is protected against the risk of overheating due to fire or extreme temperatures within the vault. Preferably, the or each battery pack (or the or each cell of each battery pack) is enclosed by a thermally insulating, fireproof wrapping. The fireproof wrapping may comprise a ceramic fibre material, such as a ceramic fibre paper. For example, the fireproof wrapping may comprise an alkaline earth silicate fibre ceramic paper. The fireproof wrapping may be held in place with a polymeric sleeve, such as a PVC shrink sleeve. The access cover may comprise a receiving portion for receiving a monitoring device module. The access cover may comprise a low attenuation region that extends between the receiving portion and a top side of the access cover, to improve radio communications between the monitoring device module. For example, the low attenuation region may comprise an aperture and/or a cover part made from a material having a relatively low radio attenuation, such as a plastics material or a plastics composite material.

Also described is a monitoring device for monitoring an underground utility vault comprising a processor, at least one sensor, a communications module for transmitting data from the device to a receiver, and an on-board power supply, such as a battery, for powering the device. The processor is configured to repeatedly obtain sensor data from the sensor at a polling time interval and to cause the communications module to repeatedly transmit reporting data derived from the sensor data to the receiver at a reporting time interval. The polling time interval and/or the reporting time interval may be dependent on the season and/or the time of the year. For example the polling and/or reporting time intervals may be relatively short during months of the year in which road salting is expected and relatively long for the remainder of the year, to minimise power consumption during the operating life of the device.

Preferred and/or optional features of each aspect and embodiment of the invention may be used, alone or in appropriate combination, in the other aspects and embodiments also.

The features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following with reference to the accompanying drawings, all of which form a part of this specification. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and the claims, the singular form of“a,”“an,” and“the” include plural referents unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described with reference to the accompanying drawings, in which like reference signs are used for like features, and in which:

Figure 1 is an exploded perspective view of an underground utility vault access cover having an integrated monitoring device module;

Figure 2 is a perspective view of the underside of the utility vault access cover of Figure 1 ;

Figure 3 is a cross-sectional view of the utility vault access cover of Figure 1 ;

Figure 4 is a cross-sectional view of the utility vault access cover of Figure 1 , with the monitoring device module installed;

Figure 5 is an exploded perspective view of a monitoring device module for use with the utility vault access cover of Figure 1 ;

Figure 6 is a block diagram of the monitoring device module of Figure 5;

Figure 7 is an exploded perspective view of another monitoring device module for use with the utility vault access cover of Figure 1 ;

Figure 8 is a cross-sectional view of the monitoring device module of Figure 7 installed in the utility vault access cover of Figure 1 ; and

Figure 9 is a cross-sectional view of a further monitoring device module installed in the utility vault access cover of Figure 1 . DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 shows a circular vented utility vault access cover 10. The access cover 10 is preferably of cast metal construction and includes vents 12, lifting eyes 14 and a central aperture 16.

Referring additionally to Figures 2 and 3, a generally cylindrical receptacle 18 is defined by a generally tubular wall 20 formed on the underside of the access cover 10. The receptacle 18 provides a receiving portion that can accommodate a monitoring device module 100, so that the monitoring device module 100 is integral with or housed within the access cover 10.

The aperture 16 forms a passage between the receptacle 18 and the top side of the access cover 10. The aperture 16 is of smaller diameter than the receptacle 18, so that an annular shoulder 22 is formed at the top end of the receptacle 18.

Referring again to Figure 1 and additionally to Figure 4, in a first embodiment of the invention, the monitoring device module 100 is generally cylindrical and is sized to fit within the receptacle 18. The module 100 can therefore be inserted into in the receptacle 18 from the underside of the cover 10. The module 100 is retained in the receptacle 18 by a retaining ring 24. The retaining ring 24 is fixed to the cover 10 by way of suitable machine screws or bolts 26 that can be screwed into cooperating threaded holes in the end face of the receptacle wall 20.

The module 100 is shaped and dimensioned to fit within the receptacle 18 of the cover 10. In one example, the receptacle 18 has an internal diameter of approximately 165 mm and a height (between the bottom end of the wall 20 and the shoulder 22) of approximately 140 mm.

The aperture 16 is closed by a disc-shaped cap 28. The cap 28 is held in place by a pair of screws or bolts 30 that extend through notches 32 formed at the periphery of the aperture 16 and are secured with washers 34 and nuts 36 (see Figure 1 ). The top side of the access cover 10 is formed with a recess 38 around the aperture 16 so that the cap 28 sits flush with respect to the top side of the cover 10.

The cover 28 is of a dissimilar material to the material of the cover 10. Preferably, the cover 28 is of a plastics material, such as a composite plastics material. One suitable cover material may be glass-reinforced plastic (GRP). The material of the cover 28 is selected to allow radio frequency propagation through the cover 28 with minimum attenuation. In this way, the cover 28 and aperture 16 provide a low attenuation region between the receptacle 18 and the top side of the access cover 10 that allows the monitoring device module 100 to transmit and receive signals effectively even when the access cover 10 is of a metallic material.

Figure 5 shows the monitoring device module 100 in more detail.

The module 100 comprises an outer housing 102 with a cylindrical wall 104 and an integral circular base 106. The wall 104 extends from the base 102 towards a top 107 of the outer housing 102. The outer housing 102 is preferably made from a plastics material. Suitable materials include thermoplastic polyester resins, such as polybutylene terephthalate resins. One suitable material is Crastin S600 F20 (registered trade mark, E. I. du Pont de Nemours and Company, DE, USA). In the illustrated embodiment, the wall 104 of the outer housing 102 has a thickness of approximately 6 mm.

The base 106 of the outer housing 102 is provided with a port 108. In this example, the port 108 is a central circular aperture that extends through the base 106. The port 108 is covered with a microporous membrane 109, preferably a stretched polytetrafluoroethylene (PTFE) material such as Gore-Tex (registered trade mark). The membrane 109 allows gas and water vapour to pass through the port 108 to reach the interior of the outer housing 102, but substantially prevents the passage of water through the port, even if the module 100 were to be immersed in water.

A main printed circuit board (PCB) 1 10 is housed in the bottom of the outer housing 102. The main PCB 1 10 includes a gas sensor, in this example a carbon monoxide sensor 1 12, and the main PCB 1 10 is mounted so that there is a clear pathway for gas entering the outer housing 102 through the port 108 to flow to the carbon monoxide sensor 1 12.

Suitable devices for use as the carbon monoxide sensor 1 12 are available under part nos. 3SPC01000 (SPEC Sensors LLC, CA, USA) and TGS5432 (Figaro USA Inc, IL, USA).

The main PCB 1 10 also includes a temperature sensor 1 14 and a humidity sensor 1 16, as well as a processor 1 18. The temperature sensor 1 14 and humidity sensor 1 16 may be integrated into a single device, such as is available under part no. SI7021_A20_GM1 (Silicon Laboratories Inc., TX, USA).

Further and/or alternative sensors may be provided for the detection of developing faults within the vault 10. For example, gas sensors for the detection of one or more of carbon dioxide, acetylene, methane and/or other gases may be provided. Other possible sensors include a smoke sensor, an electrical arc sensor, a stray voltage sensor, a water sensor, a tamper sensor, an atmospheric pressure sensor, a light sensor, an audio sensor, and so on.

A communications module 120, embodied as a separate PCB in this example, is also housed in the outer housing 102. The communications module PCB 120 includes at least one modem capable of transmitting and receiving data using suitable protocol. In the illustrated example, the communications module PCB 120 includes an LTE and/or NB/loT modem 122 for cellular network communications and a mesh network modem, such as an Itron Networked Solutions (INS) modem 124 for mesh network communications. The communications module PCB 120 connects with the main PCB 1 10 by way of a suitable interface 126, for example a serial interface.

The communications module PCB 120 connects with at least one radio antenna 130 to facilitate radio frequency communication between the modems 122, 124 and the corresponding networks. In this example, the antenna 130 is mounted in an upright position within the outer housing 102 to maximise reception. The antenna 130 is spaced away from the top of the outer housing 102.

The monitoring device module 100 is powered by a plurality of battery packs 132, only one of which is shown. The battery packs 132 are designed to allow 8 years or more of continuous operation. Preferably, each battery pack 132 comprises a plurality of lithium cells.

To reduce the risk of fire, each battery pack 132 is protected by a thermally insulating wrapping. The wrapping comprises a flameproof sheet material, preferably a ceramic wool or paper such as an alkaline earth silicate fibre paper material. One suitable material is available under the registered trade mark“Superwool” (Morgan Advanced Materials, Worcs., UK). Other suitable materials include refractory ceramic fibre/alumino silicate wool materials and polycrystalline fibre materials.

The flameproof sheet material is wrapped around the cells individually or in groups, and is preferably held in place by a plastics sleeve (such as a 0.2 mm thick PVC UL224 heat shrink sleeve). The wrapping prevents the lithium cells of the battery pack 132 from overheating in the event of a fire in the utility vault, therefore reducing the risk of explosion.

The battery packs 132 are housed in a leak-proof inner container 134. The inner container 134 is preferably of a metallic material. The inner container 134 comprises a tubular outer side wall 136 and a tubular inner side wall 138, arranged concentrically to define an annular chamber 140 for receiving the battery packs 132. The bottom of the inner container 134 is closed by an annular base 142. The inner side wall 138 defines a cylindrical space or cavity 144 in which the communications module PCB 120 and the antenna 130 are housed.

The cavity 144 defined by the inner side wall 138 of the inner container 134 provides a low-attenuation pathway for the propagation of radio signals from the antenna 130 to the top of the module 100. The pathway provided by the cavity 144 is free from components and materials that would act to substantially attenuate the propagation of radio signals. For example, the material of the inner container 134 does not intrude into the cavity 144 so that, if the inner container 134 is of metal or another attenuating material, radio waves from the antenna 130 can still propagate from the antenna towards the top of the housing and out of the module 100 without significant attenuation.

The outer diameter of the inner container 134 is sized so that the inner container 134 can be slid inside the outer housing 102. A plurality of inwardly-extending ledges 145 are disposed on the inner side of the outer housing wall 104 to support the inner container 134 above the main PCB 1 10.

The top of the monitoring device module 100 is closed by a disc-shaped lid 146 that is attachable to the top 107 of the wall 104 of the outer housing 102 with suitable bolts or screws 148. The lid 146 may be of a plastics material, preferably the same material as the outer housing 102. In this way, the lid 146 does not substantially attenuate the radio signals from the antenna 130. An elastomeric O-ring 150 is disposed between the lid 146 and the top end of the outer housing wall 104 to provide a water-tight and gas-tight seal when the lid 146 is in place.

The outer housing 102 is thus protected against water ingress by the lid 146 and the O-ring 150 and by the membrane 109 of the port 108. With these features, the monitoring device module 100 achieves an ingress protection (IP) rating of IP68 and is capable of withstanding immersion in water for 7 days or more at a depth of approximately 1 m.

For maintenance purposes, for example battery replacement, the monitoring device module 100 can be removed from the access cover 10 by lifting the access cover 10, removing the retaining ring 24, and sliding the module 100 out of the receptacle 18. The interior of the module 100 can then be accessed by removing the lid 146. Advantageously, in this example, the module 100 is entirely self-contained with no further physical connection to the access cover 10.

Figure 6 is a block diagram showing hardware components of the monitoring device module 100. The components are as described above. In addition, an on-board flash memory device 152 is provided. The device module 100 communicates with a remote server 154, where data from the device module 100 can be viewed and processed by a user interface 156, for example a web interface. The LTE/NB-loT modem 122 communicates with the remote server 154 through a cellular network 158. Communication between the LTE/NB-loT modem 122 and the remote server 154 may be through a virtual private network (VPN). The ISN modem 124 communicates with the remote server 156 through a mesh network 160. It will be appreciated that only one modem 158, 160 could be provided, but where both modems 158, 160 are present they can be used in parallel or in a primary and backup arrangement.

The processor 1 18 is configured to read data from the carbon monoxide sensor 1 12, the temperature sensor 1 14 and the humidity sensor 1 16 at a configurable polling time interval. The processor 1 18 is further configured to cause, at a configurable reporting time interval, transmission of a data report, based on the sensor data, to the remote server 154 by way of one or both of the modems 122, 124.

The polling and reporting time intervals can be set at any suitable value. Advantageously, the polling and reporting time intervals are selected so that data is transmitted to the remote server frequently enough to allow developing faults within the vault to be identified and rectified before they become serious or dangerous. However, the battery life of the monitoring device 100 decreases with increasing polling and reporting frequency.

In embodiments of the present invention, the polling and/or reporting time intervals are adjusted over time in accordance with the statistical likelihood of a fault developing. The polling and/or reporting time intervals can be increased when a fault is statistically more likely to occur and decreased when a fault is statistically less likely to occur. Preferably, the polling and/or reporting time intervals are seasonally adjusted. For example, the polling/reporting time intervals may be set for a period of at least one month at a time.

For example, road salting is a significant cause of faults in vaults, due to increased corrosion rates and the increased risk of arcing where brine is present. Accordingly, in an embodiment, the polling and reporting rate may be relatively high (i.e. a short polling/reporting time interval) during winter months, when salt is likely to be applied to the roads, and relatively low (i.e. a long polling/reporting time interval) during other seasons. In this way, the battery life can be maximised over the course of several years, while still allowing the vault conditions to be monitored closely when a fault is most likely.

In one example, the polling time interval and the reporting time interval are both set to equal 24 hours (i.e. one report per day) during the months of February to April, and are both set to equal 336 hours (i.e. one report every two weeks) during the months of May to January. It will be appreciated that the times of year and lengths of time during which the polling time interval and/or reporting time interval are reduced may vary according to geographical location and local environment.

In the above example, the reporting time interval is the same as the polling time interval. Flowever, to conserve battery life, the reporting time interval may be longer than the polling time interval. For instance, in some cases, the reporting time interval may have a value of 24 hours, and the polling time interval may have a value of 2 hours.

The processor 1 18 may also be configured to monitor the data from one or more of the sensors 1 12, 1 14, 1 16 to determine whether an alarm state is present. An alarm state may be present, example, when the output of a sensor exceeds a pre- determ ined threshold or when the rate of change of the output exceeds a pre- determined rate. The processor 1 18 may be configured so that, when the processor 1 18 determines that an alarm state is present, an alarm data packet is transmitted to the remote server 154 immediately (or as soon as possible).

In some embodiments, an alarm state is identified when the carbon monoxide level exceeds a threshold value of between approximately 20 ppm (parts per million) and approximately 50 ppm. In some embodiments, the threshold value is between approximately 30 ppm and approximately 40 ppm. In preferred embodiments, the threshold value is approximately 35 ppm.

The on-board flash memory device 152 can be used for logging sensor data. Thus the processor 1 18 may be configured to write sensor data to the memory 152 at the polling and/or reporting time intervals. The stored data in the memory 152 can provide a backup in the event of a communications failure or delay.

The firmware of the device module 100 can preferably be updated over-the-air. Thus the device module 100 can be configured to receive data from the remote server 154 (or from an alternative source) via one of the modems 122, 124. The flash memory 152 can be used to provide temporary storage from over-the-air updates.

Network communications and stored data are encrypted to prevent unauthorised access to the data and to the device module 100. The cellular and stored data may, for example, be encrypted to the AES 256 standard. The mesh communication data may include suitable multi-layer security with built-in controls from the application to device layer.

The processor 1 18 may be configured to determine the voltage of the battery packs 132 and to cause the modems 122, 124 to transmit the voltage data to the remote server 154, so that the battery condition can be monitored at the web interface 156.

Figures 7 and 8 show a monitoring device module 200 according to a second embodiment of the invention. The monitoring device module 200 is generally similar to the module 100 described above with reference to Figures 1 to 6, and only the differences will be described in detail. Features of the module 200 of Figures 7 and 8 that correspond to features of the module 100 of Figures 1 to 6 are indicated with reference numerals incremented by 100.

In this second embodiment, the inner container 234 is longer than in the first embodiment, so that the inner container 234 occupies substantially the whole height of the interior of the outer housing 202. When assembled, the base 242 of the inner container 234 rests on the base 206 of the outer housing 202, as can be seen in Figure 8.

The main PCB 210 of the module 200 has a smaller diameter than the main PCB 1 10 of the first embodiment. In this way, the main PCB 210 can be accommodated in the cylindrical cavity 244 of the inner container 234, with a clearance between the edge of the main PCB 210 and the tubular inner side wall 238 of the inner container 234 as best shown in Figure 8. The main PCB 210 is supported on a pair of legs 245 that extend upwardly from the base 206 of the outer housing 202, and is secured to the legs 245 by machine screws or other suitable fixings.

Referring back to Figure 7, the main PCB 210 includes a carbon monoxide sensor 212, a temperature sensor 214, a humidity sensor 216 and a processor 218. The main PCB 210 connects with a communications module 220 via an interface 226. The communications module 220 connects with a radio antenna 230. The components of the main PCB 210, the communications module 220 and the antenna 230 function in the same way in the first embodiment as described above. The communications module 220 and the antenna 230 are not shown in Figure 8, but are housed in the cylindrical cavity 244 as in the first embodiment. The cavity 244 provides a low-attenuation pathway for the propagation of radio waves from the antenna 230 towards the top 207 of the outer housing 202.

As can be seen most clearly in Figure 8, the port 208 in the base 206 of the outer housing 202 comprises an aperture 21 1 in the base 206 that opens into interior of the housing 202 between the legs 245. A microporous membrane 209 is held over the aperture 21 1 by a support ring 213, which in turn is attached to the base 206 by machine screws or other suitable fixings. As in the first embodiment, the membrane 209 allows gas and vapour to pass through the port 208 to reach the interior of the outer housing 202 for detection and measurement by the sensors 212, 214, 216.

As in the first embodiment, in this second embodiment a plurality of battery packs 232 are housed in the annular chamber 240 defined between the outer side wall 236 and the inner side wall 238 of the inner container 234. It will be appreciated that, in the module 200 of Figures 7 and 8, the annular chamber 240 has a larger volume than in the module 100 of Figures 1 to 6.

Figure 8 shows, in cross section, how each cell 233 in a battery pack 232 is wrapped in the thermally insulating wrapping 235.

Still referring to Figure 8, the disc-shaped lid 246 includes an annular flange 247 on its underside. The flange 247 has a C-shaped profile in cross section, and serves to retain the O-ring 250. When the lid 246 is secured to the wall 204 of the outer housing 202 with suitable fastenings 248 (not shown in Figure 8), the flange 247 holds the O-ring 250 in place against the inside surface of the wall 204, thereby to create a watertight seal between the lid 246 and the wall 204.

As in the first embodiment, in this second embodiment the module 200 is retained in the receptacle 18 of the cover 10 by a retaining ring (not shown in Figure 8), and the aperture 16 is closed by a disc-shaped cap (not shown in Figure 8).

Figure 9 shows a monitoring device module 200a, which is substantially the same as the module 200 of Figures 7 and 8. Only the differences will be described in detail, and like reference numerals are used for like features.

The module 200a is additionally provided with a stray voltage detector, which in this example is arranged to monitor stray voltages on the access cover 10 (which in this case would be of metal material). The stray voltage detector comprises a stray voltage detector module 270, shown schematically as a surface mounted component on the main PCB 210 (although it will be appreciated that the stray voltage detector module 270 could instead be integrated with other components on the main PCB 210 or provided on a separate PCB).

The stray voltage detector module 270 is electrically connected to an access cover contact 272. The access cover contact 272 comprises, in this example, a spring- loaded stud 274 that is arranged so that, when the module 200a is mounted in the receptacle 18 of the cover 10, the stud 274 bears against the wall 20 to form an electrical connection between the stray voltage detector module 270 and the metal cover 10. This connection provides a sensor input for the stray voltage detector.

The stray voltage detector module 270 is also electrically connected to a flying lead 276, shown schematically in Figure 9. The flying lead exits the module 200a through a watertight grommet 278 installed in the base 206 of the outer housing 202. The flying lead is connected to a suitable electrical ground or electrically neutral point within the utility vault, to provide a reference input for the stray voltage detector.

The stray voltage detector module is configured to monitor the potential difference between the sensor input and the reference input. If the potential difference exceeds a threshold indicative of a stray voltage becoming present on the cover 10, an alarm state may be identified and appropriate further steps may occur. For example, an alarm data packet may be transmitted from the module 200a as described above.

Other configurations of the stray voltage detector module are possible. For instance, one or more further flying leads could be provided to provide alternative or further sensor inputs for the stray voltage detector module, allowing the detection of stray voltages on other parts of the utility vault. The or each flying lead may be fitted with an alligator clip, spring clip, magnetic contact or a similar connector for ease of installation. Various modifications to the illustrated embodiments are possible.

For example, the monitoring device module may be retained in the receptacle of the access cover by any suitable means, such as clips, latches and so on. It is conceivable that the monitoring device module could be held on to the underside of the access cover using straps or clips.

It is also possible that the outer housing could include attachment means to allow the monitoring device module to be mounted in an alternative location within a utility vault, so that the monitoring device module can be installed in a vault even if the access cover is not adapted to receive or retain the module. The attachment means may for example comprise one or more lugs, tabs or other formations arranged to cooperate with a cable tie or strap-type fastener, to allow the module to be secured to a cable, conductor, bracket or other suitable formation inside the utility vault.

The outer housing, inner container and other components may be of a different shape and form factor to those illustrated. For example, the outer housing could be cuboidal or disc-shaped. The inner container need not be of an annular shape. The inner container could instead be tubular, cuboidal or any other suitable shape.

In some arrangements, a separate inner container is not provided, and the or each battery pack is housed in the outer housing.

In further arrangements, a plurality of inner containers may be provided. For example, a set of inner containers, each being arc-shaped in cross-section, may be used, with the cylindrical cavity being defined by the radially innermost side walls of each container in combination, each side wall having an arcuate cross section. In such cases, an inner container may be provided for each battery pack, or a plurality of battery packs may be installed in each container. In another arrangement, a plurality of annular-shaped inner containers stacked on top of one another may be provided. When a plurality of inner containers is provided, the containers may be removable from the outer housing individually, or they may be attached to one another and thus removable as a set. It is also possible that one or more of the inner containers may be empty or may be used to house other components.

In the above-described examples, the space that provides the low-attenuation pathway is cylindrical and is defined by a tubular side wall of the inner container or by a plurality of arcuate side walls where more than one inner container is present. Furthermore, the space extends centrally through the module. However, in other arrangements, the space could be non-cylindrical and/or could be disposed non- centrally in the module. For example, the inner container may be part-cylindrical in shape and disposed on one side of the housing, with a planar side wall defining, in part, a part-cylindrical space.

The device may be powered by a single battery pack or, as in the illustrated examples, a plurality of battery packs. The or each battery pack may provide the only power source for the monitoring device module. However, it is also conceivable that other power sources could be provided in addition to or instead of battery packs. For instance, the module may be provided with or connected to an energy harvesting device to provide power directly to the module and/or to charge the or each battery pack. Examples of energy harvesting devices include solar cells, piezoelectric generators (for generating energy from mechanical loading of the cover), magnetic induction coils (for harvesting energy from power cables within the vault), and so on.

Further or alternative sensors may be provided on the main PCB or elsewhere in the module. Such sensors may be used to monitor further or alternative environmental variables associated with the utility vault, such as water ingress, smoke generation, sound, light, and so on. Furthermore, two or more sensors may be used to monitor the same variable, to provide redundancy and/or data verification. For example, two carbon monoxide sensors, using different sensing technologies, may be provided. One or more sensors to monitor the condition and/or environment of the access cover itself may be provided. For example, the module may include an accelerometer to detect movement of the access cover. In this way, the module can be configured to report to the remote server when the accelerometer data indicates that the access cover has been removed or disturbed, potentially indicating unauthorised removal of the cover and/or access to the vault.

In one embodiment (not illustrated), the module is provided with an imaging device in the form of a camera. The camera is mounted to the base of the outer housing so that at least a part of the interior of the vault is in the field of view of the camera. To this end, the camera may be installed in a moveable housing so that the camera can be angled appropriately during commissioning of the module. The module may be configured to cause the camera to capture an image of the interior of the vault and to transmit the image to the remote server or receiver. For example, an image may be captured and transmitted when an alarm state is identified, to allow a user at the receiver end to examine the image to confirm the presence and nature of a potential fault. The camera may be configured to capture visible light and/or infrared images.

In the illustrated embodiments, the antenna of the communications module is a separate component. Flowever, in other arrangements, the antenna may be surface- mounted on the PCB of the communications module. In further arrangements, the communications module and/or the antenna may be integrated with the main PCB. In each case, the antenna is disposed either in the cavity or at an end of the cavity so that the radio signals can propagate from the antenna to the top of the housing through the low-attenuation pathway provided by the cavity.

In the illustrated embodiments, the device transmits data to a receiver in the form of a remote server. Flowever, the device may transmit data to a receiver of a different form. Examples of receivers include, but are not limited to, a computing device such as a server, one or more computers, portable computers, tablet computers, cellular phones, wearable devices (e.g. watches, glasses, lenses, clothing and/or the like), personal digital assistants (PDAs), a processor, a storage device, and/or similar computer components. The receiver may be capable also of transmitting data to the device as well as receiving data from the device. The devices and/or components described herein can perform one or more processes described herein. For example, the devices and/or components can perform at least a portion of such processes based on a processor executing software instructions stored by a computer-readable medium, such as memory and/or storage component. A computer-readable medium (e.g., a non-transitory computer-readable medium) is defined herein as a non-transitory memory device. A memory device includes memory space located inside of a single physical storage device or memory space spread across multiple physical storage devices.

When executed, software instructions stored in a computer-readable medium may cause a processor to perform one or more processes described herein. Additionally, or alternatively, hardwired circuitry may be used in place of or in combination with software instructions to perform one or more processes described herein. Thus, embodiments described herein are not limited to any specific combination of hardware circuitry and software.

Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the invention. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

1. A monitoring device module for a utility vault access cover, the module comprising:

at least one inner container; and

and wherein at least part of a side wall of the or each inner container defines a space within the housing providing a low-attenuation pathway for the propagation of radio signals from the radio antenna, the pathway extending from the radio antenna towards the top of the housing.

2. A monitoring device module according to Claim 1 , wherein the or each inner container does not intersect the space.

3. A monitoring device module according to Claim 1 or Claim 2, wherein the or each inner container is formed from a metallic material, and wherein the housing is formed from a non-metallic material.

4. A monitoring device module according to any preceding claim, wherein the housing is formed from a plastics material.

5. A monitoring device module according to any preceding claim, wherein the housing comprises a side wall that extends upwardly from the base to enclose an interior of the housing.

6. A monitoring device module according to Claim 5, comprising a lid arranged to form a seal against the side wall to close the top of the housing.

7. A monitoring device module according to Claim 6, wherein the lid is of a plastics material.

8. A monitoring device module according to any preceding claim, wherein the or each inner container is supported by the base of the housing.

9. A monitoring device module according to any of Claims 5 to 7, wherein the side wall of the housing comprises one or more support elements for supporting the or each inner container such that the or each inner container is spaced from the base of the housing.

10. A monitoring device module according to any preceding claim, wherein the housing comprises a port for allowing gas exchange between the environment outside the housing and the interior of the housing, the port being arranged to prevent water ingress from the exterior into the interior of the housing.

11. A monitoring device module according to Claim 10, wherein the port comprises a micropermeable membrane that allows gas flow through the port and prevents water ingress through the port.

12. A monitoring device module according to any preceding claim, wherein the or each inner container comprises an inner side wall and an outer side wall defining the chamber therebetween, and wherein the space is defined at least in part by the inner side wall of the or each container.

13. A monitoring device module according to Claim 12, wherein the or each inner side wall and the or each outer side wall are tubular such that the space is cylindrical and the or each chamber is annular.

14. A monitoring device module according to any preceding claim, wherein the or each inner container comprises a base, and wherein the or each side wall of the inner container is upstanding from the base.

15. A monitoring device module according to any preceding claim, wherein the or each inner container comprises an open top providing access to the chamber, and wherein the bottom of the chamber is closed.

16. A monitoring device module according to any preceding claim, wherein the radio antenna is disposed in or extends into the space.

17. A monitoring device module according to any preceding claim, wherein the at least one environmental sensor includes a carbon monoxide detector.

18. A monitoring device module according to any preceding claim, wherein the at least one environmental sensor includes a temperature sensor.

19. A monitoring device module according to any preceding claim, wherein the at least one environmental sensor includes a stray voltage detector.

20. A monitoring device module according to Claim 19, comprising an electrical contact providing an input for the stray voltage detector, the electrical contact being disposed on the housing and arranged to contact the access cover in use.

21. A monitoring device module according to any preceding claim, wherein the power source comprises one or more battery cells.

22. A utility vault access cover, comprising:

a monitoring device module according to any preceding claim; and a receptacle for receiving the monitoring device module, the receptacle being disposed on an underside of the access cover such that, in use, the module is exposed to an internal environment of the utility vault.

23. A utility vault access cover according to Claim 22, wherein an aperture is provided in the access cover between the receptacle and an upper side of the access cover to provide a low-attenuation pathway for the propagation of radio waves from the monitoring device module through the access cover.

24. A utility vault access cover according to Claim 23, wherein the aperture is closed by a cap comprising a low-attenuation material.

25. A utility vault access cover according to Claim 24, wherein the cap comprises a composite plastics material.