GB2622605A

GB2622605A - Air quality sensing apparatus

Info

Publication number: GB2622605A
Application number: GB2213833.3A
Authority: GB
Inventors: Edward Thomas White Matthew
Original assignee: Elta Group Ltd
Current assignee: Elta Group Ltd
Priority date: 2022-09-22
Filing date: 2022-09-22
Publication date: 2024-03-27
Also published as: GB202213833D0

Abstract

Air quality sensing apparatus comprising a housing 20 having an air inlet 28 to an internal volume and an attachment means for attaching the housing to a ceiling 12 or wall; a circuit substrate (FIG 3, 54) in the internal volume of the housing which has at least one air quality sensor (FIG 3, 56) mounted thereon, the circuit substrate is positioned within the housing with the air quality sensor on an in-use downward facing side of the circuit substrate when the housing is mounted. Another air quality sensing apparatus comprises a housing with two air inlets, two air quality sensors on a substrate, one mounted near each inlet, the sensors being isolated from one another. Another air quality sensing apparatus comprises an air quality sensor, a mount, an electrical coupling device, support member and securing means.

Description

Air Quality Sensing Apparatus The present invention relates to an air quality sensing apparatus, and in particular one which has improved sensing capabilities within the room in which it is installed.

Airflow control within a building is controlled by one or more airflow control devices, 5 typically ventilation fans, positioned around the building. Some ventilation systems may be activated in response to sensing of unexpected changes to the gas composition of the air in order to flush the building of contaminants.

This has several problems: firstly, air quality sensing is difficult, and therefore existing sensors will be calibrated to a specific gas to be sensed, such as carbon monoxide. If 10 more than one gas is desirable to be monitored, then the installer must create multiple gas sensing systems. This is extremely unwieldy.

Secondly, the air being detected by any sensor must be indicative of the air quality which is of interest. Therefore, introducing artificial air currents into any system may provide inaccurate sensing results as gases which should be detected can be easily and 15 accidentally flushed from the sensor apparatus.

Thirdly, the systems are extremely non-portable, and must be installed bespoke to a building. This is time-consuming and prohibitively expensive. Maintenance of the systems can therefore be challenging, if any of the delicate sensing componentry becomes dislodged or damaged.

Furthermore, for ventilation and filtration systems in buildings, it is useful to know what the status of the air being treated is. Typically, the system owner will be interested in the gas composition, particularly in relation to carbon dioxide and pollutants, as well as an indication of the level of particulate matter in the air.

An air quality sensor can be used to provide this information. However, there are various 25 challenges associated with air quality monitoring.

Firstly, where lots of different air quality characteristics are to be measured, an equivalent number of sensors is required. This can result in a bulky device, which is not aesthetically pleasing, and/or is cumbersome to move.

Where bulky components are present, this can necessitate a large internal volume of the device, which may require air circulation, again producing inaccurate sensing data.

Furthermore, the largely sealed nature of such air quality sensor devices is required to prevent damage or contamination of the sensor components. However, this can lead to 5 clogging of the air inlet and outlet of the device with dust, since the user cannot readily clean the device.

It is an object of the present invention to obviate or overcome the above-referenced difficulties.

According to a first aspect of the invention, there is provided an air quality sensing apparatus comprising: a housing having an air inlet to an internal volume; an attachment means for attaching the housing to a ceiling or wall; and a circuit substrate positioned in the internal volume of the housing, the circuit substrate having at least one air quality sensor mounted thereon; the circuit substrate being positioned within the housing such that the at least one air quality sensor is on an in-use downward-facing side of the circuit substrate when the housing is mounted to a ceiling or wall via the attachment means.

The provision of downward-facing sensors within an air quality sensing apparatus ensures that there is minimal dust accumulation on the sensors, which is the most common reason for diminished sensing capability and/or maintenance requirements for the apparatus. As such, a more effective and accurate apparatus is produced.

Optionally, the housing may comprise a lower cover receivable over the in-use downward-facing side of the circuit substrate, the lower cover having a sloped surface towards the air inlet.

A sloped cover encourages ejection of dust from the apparatus, which might otherwise build up and impede the operation of the air quality sensors therein. Dust is able to fall 25 out of the air inlet under gravity.

Preferably, the circuit substrate may be provided as an air quality sensing device releasably engageable with the housing.

By providing a dedicated air quality sensing device as a unitary component which can be rapidly disengaged from the mount of the apparatus, quick replacement of the air quality sensing device can be performed, without needing to fully disassemble the air quality sensing apparatus.

The air quality sensing apparatus may further comprise a failsafe support for at least one air quality sensor, the failsafe support being positioned spaced apart from the downward-facing side of the circuit substrate to support the at least one air quality sensor if the at least one air quality sensor becomes partially dislodged from the circuit substrate during use.

Given the downward-facing nature of the air quality sensors, there is a natural tendency towards dislodging from their substrate under gravity. This effect can be counteracted by the provision of a failsafe support to effectively catch the air quality sensors before they become entirely electrically disconnected from the circuit substrate. By providing the failsafe support as part of a cover, or in this case, the air-calming element of the air quality sensing device, there is no impediment to the ease of installation of the air quality sensors.

Optionally, the failsafe support may be formed as a perimetric frame for the at least one air quality sensor.

A failsafe support in the form of a perimetric frame has the advantage of retaining the air quality sensors in position without impeding the airflow at the sensing components thereof.

The air quality sensing apparatus may further comprise an air-calming element in the housing spaced apart from the downward-facing side of the circuit substrate.

The air-calming element helps to limit the effect of air currents within the housing. It is desirable for the air to be equivalent to that present within the room in which the air quality sensing apparatus is installed, and therefore mitigating large air currents can be helpful.

Preferably, the attachment means may comprise an elongate support member engageable with a ceiling.

A stem-like support which depends from a ceiling allows the air quality sensing device of the air quality sensing apparatus to be mounted within a room in a position which is best able to monitor breathable air quality, in spite of being ceiling-mounted.

Optionally, a plurality of said air quality sensors is provided.

Where a plurality of air quality sensors is provided, different gas concentrations can be monitored which allows for a more complete understanding of the overall air quality to be characterized.

In one arrangement, the plurality of air quality sensors may comprise a plurality of different gas sensors, the plurality of gas sensors each have a primary gas sensitivity and at least one secondary gas sensitivity, the air quality sensing apparatus being configured to determine at least one gas concentration which is not related to any of the primary gas sensitivities based on the at least one secondary gas sensitivities of the plurality of gas sensors.

Cross-sensitivity data allows for the identity of unknown gases to be elided, without needing to add dedicated sensors for those gases to the circuit substrate. This greatly increases the utility of the apparatus. The use of cross-sensitivity information could be used more generally across a wide range of different air quality sensing apparatuses, and is not just limited to use in the present apparatus.

The air quality sensing apparatus may further comprise an onboard processor.

An onboard processor allows for real-time cross-sensitivity data to be determined, in addition to other functions which may only be feasible with processing power. For example, a processor can provide control function to alerts within the air quality sensing apparatus, or can allow for communication with other linked devices.

According to a second aspect of the invention, there is provided an air quality sensing apparatus comprising: a housing having an internal volume, the housing having a first air inlet communicable with the internal volume and a second air inlet communicable with the internal volume; and a circuit substrate positioned in the internal volume of the housing, the circuit substrate having a first air quality sensor mounted on a first side of the circuit substrate so as to be communicable with the first air inlet, and a second air quality sensor mounted on a second side of the circuit substrate so as to be communicable with the second air inlet; the first and second air quality sensors being isolated from one another within the internal volume of the housing.

It is desirable for there to be minimal artificial air currents within the main housing, at or 30 adjacent to the primary gas sensors of the air quality sensing apparatus. This ensures that air within the apparatus is indicative of the air within the room, rather than being artificially recycled through the device. However, a particulate sensor requires an onboard fan to operate correctly. As such, there is a desire to isolate the primary gas sensors from the particulate sensor so that the particulate sensor does not create artificial disturbances within the apparatus. Better quality measurements therefore become feasible with the present invention.

Optionally, a plurality of first air quality sensors may be provided.

VVhere a plurality of air quality sensors is provided, different gas concentrations can be monitored which allows for a more complete understanding of the overall air quality to be characterized, all within the same isolated air zone.

In one preferable embodiment, the second air quality sensor may be a particulate sensor.

As previously noted, the particulate sensor requires an airflow across it, and therefore it is desirable to be isolated and exhausted separately to the other gas sensors.

The second air quality sensor may be releasably engagable from the circuit substrate from an exterior of the housing.

The isolation of the second sensor means that there may be quick and easy access thereto to permit separate release thereof. Since the particulate sensor is most likely to become clogged with dust, particularly where the other sensors are on a downward-facing surface of the circuit substrate, the ability to separately remove the particulate sensor for maintenance or cleaning becomes quite valuable.

Optionally, the second air quality sensor may be engaged with the housing via an enclosure moulding.

A dedicated enclosure moulding may be the simplest means of creating an isolation zone within the housing by enclosing the air inlet and outlet of the second sensor as necessary.

Preferably, the enclosure moulding may be releasably engagable with the housing.

Releasable engagement of the enclosure moulding means that the second sensor can itself be accessed without complete disassembly of the entire apparatus. It also reduces the difficulty of assembly, since there will be greater tolerance with the enclosure moulding than with a pre-moulded part of the housing designed to receive the second sensor.

It is preferably that there is no fan associated with the first air inlet.

As previously noted, it is desirable to avoid unnatural air currents within the housing at or adjacent to the first sensors, and the absence of a fan is intentional.

According to a third aspect of the invention, there is provided an air quality sensing 5 apparatus comprising: an air quality sensing device comprising at least one air quality sensor; and a mount for securely mounting the air quality sensing device to a surface in a room, the mount comprising: a device coupling for providing electrical connection between the mount and the air quality sensing device; a support member engageable between the device coupling and the surface; and a securing means for providing a 10 secure connection between the support member and the air quality device when engaged with the device coupling.

Quick release of the air quality sensing device from its mount allows for the device to be replaced for easy maintenance, rather than the entire apparatus. Maintenance down time is thus reduced, since repairs can be performed off-site.

Optionally, the support member may be an elongate support member.

The presence of an air quality sensing apparatus at or close to the main breathable air within the room in which it is installed will ensure that the air composition sensed is indicative of the breathable air itself. This can be achieved from a ceiling-mounted apparatus by the use of an elongate mount.

Preferably, the support member may comprise a convection current vent.

Small amounts of heating from the electrical componentry will slowly increase the temperature within the apparatus. It is thus preferred that a vent or similar be provided to allow for convection to occur, which will result in comparatively slow air movement through the internal volume of the housing, compared with an equivalent driven air flow from a fan.

Optionally, the device coupling may be formed as a base plate engageable with the air quality sensing device.

A base plate makes interconnection of the air quality sensing device and the mount more straightforward, particularly when the mount itself is a thin elongate support which would 30 otherwise be challenging to connect with.

The air quality sensing apparatus may further comprise a cover, the cover forming a housing for the air quality sensing device with the device coupling.

A releasable cover allows for easy access to the air quality sensing device for repair and replacement, without requiring full disassembly of the whole apparatus.

The housing may be at least in part light-transmissible, and further comprising at least one status-indicator light in the housing.

Light can be used to indicate a status of the apparatus, particularly where there are issues such as detection of poor air quality, or a defect in the device. An at least in part light-transmissible housing allows for the indicator to be seen from a distance, making it 10 more obvious to occupants of the room.

Optionally, the support member may comprise a castellated surface-connector directly engagable with the surface to which the mount is connected.

A castellated surface-connector, such as a ceiling connector, allows for a simple interference fit to be made with the main part of the mount, providing a residual holding force whilst the sturdier fixings are installed correctly. This simplifies the installation process.

Preferably, the mount may be provided as a modular kit of parts.

A multi-part mount has the advantage of being more easily shipped and installed, since the components which are difficult to install can be more easily connected to more 20 traditional brackets and connectors.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows an isometric view of a first embodiment of an air quality sensing apparatus in accordance with the present invention; Figure 2 shows a partially exploded isometric view of the air quality sensing apparatus of Figure 1; Figure 3 shows an exploded isometric view of the air quality sensing apparatus of Figure 1; Figure 4 shows a rear exploded isometric view of the housing of the air quality sensing apparatus of Figure 1; Figure 5A shows a front isometric view of the air quality sensing device of the air quality sensing apparatus of Figure 1; Figure 5B shows a rear isometric view of the air quality sensing device of Figure 5A; Figure 6 shows a partially exploded isometric view of the air quality sensing device of Figure 5A; Figure 7 shows an exploded isometric view of the air quality sensing device of 10 Figure 5A; Figure 8A shows a lower isometric view of the circuit substrate of the air quality sensing device of Figure 7; Figure 8B shows a top isometric view of the circuit substrate of the air quality sensing device of Figure 7; Figure 9A shows a front view of the air quality sensing apparatus of Figure 1, Figure 9B shows a cross-sectional representation of the air quality sensing apparatus of Figure 9A, taken along plane A-A; Figure 10A shows a front view of the air quality sensing apparatus of Figure 1; Figure 10B shows a cross-sectional representation of the air quality sensing 20 apparatus of Figure 10A, taken along plane B-B; Figure 11A shows a side view of the air quality sensing apparatus of Figure 1; and Figure 11B shows a cross-sectional representation of the air quality sensing apparatus of Figure 9A, taken along plane C-C.

Referring to Figures 1 and 2 there is an air quality sensing apparatus, referenced globally at 10, which is intended to be mounted to a ceiling 12 of a room, so as to depend therefrom and provide air quality information as close to a respiration zone within the room as possible The air quality sensing apparatus 10 comprises a mount 14 which at least in part forms an attachment means for engaging with the ceiling 12. An air quality sensing device 16 5 is then provided at a lower end 18 of the mount 14, here contained within a housing 20 connected to the mount 14.

The mount 14 here has an elongate support member 22 which interconnects a ceiling connector 24 and a baseplate 26 of the housing 20. It is the elongate support member 22 which allows the air quality sensing device 16 to be considerably spaced from the ceiling 12. There is an air inlet 28 positioned on a downward-facing side 30 of the air quality sensing apparatus 10, as well as a secondary air inlet 32 on a wall 34 thereof.

The air quality sensing apparatus is illustrated in more detail in Figure 3. The mount 14 comprises upper and lower pedestal interfaces 36a, 36b which connect to either end of the elongate support member 22. The upper pedestal interface 36a connects to the ceiling connector 24, which is formed as a castellated element which allows for a slight retaining force to be applied to the upper pedestal interface 36a as installation occurs, simplifying the installation process.

The lower pedestal interface 36b is releasably connectable with the baseplate 26 of the housing 20. The mount 14 is preferably hollow, which allows for an electrical connector 38 to extend therethrough and couple with a complementary coupling 40 positioned on the baseplate 26. The electrical connector 38 and coupling 40 may be quick-release, which allows for the easy disengagement of the air quality sensing device 16 from the mount 14.

The air quality sensing device 16 is secured to the mount 14 by simple fastener 25 connection, here by a pair of threaded fasteners 42 engagable from an upper side of the lower pedestal interface 36b. This allows the air quality sensing device 16 to be easily disengaged without completely removing the mount 14 from the ceiling 12.

The housing 20 is preferably a two-part housing the baseplate 26 and a lower cover 44. The baseplate 26 is then directly connectable to the air quality sensing device 16 so that 30 an electrical connection can be easily made therebetween. A complementary coupling 46 may be provided which is connectable to the coupling 40 of the baseplate 26. The lower cover 44 has an air inlet 28 therein to allow for ventilation of the air quality sensing apparatus 10.

The air quality sensing device 16 also has a two-part casing 48, comprising first and second parts 50, 52, which here take the form of a main casing 50 and an air-calming 5 element 52.

A circuit substrate 54 is provided which mounts the air quality sensors 56 of the air quality sensing device 16, and which will be described in more detail below. The circuit substrate 54 is received in the two-part casing 48, being protected by the air-calming element 52, here illustrated as a mesh frame receivable between the circuit substrate 54 and in turn by the lower cover 44 of the housing 20.

The lower cover 44 is preferably quick release to allow for easy dust extraction from the internal surface thereof or from the air-calming element 52. The main casing 50 of the two-part casing 48 is preferably at least in part light-transmissible, so that light-emitting indicator elements provided within the housing 20 or casing 48 can be used to indicate to an external user a status of the air quality sensing device 16. For example, this could be an indication that air quality is too poor, by the use of a red warning light. A perimetric lip 58 is provided on the main casing 50 so that a light-transmissible part of the air quality sensing device 16 is always present at an external surface of the air quality sensing apparatus 10.

An enclosure moulding 60 is also provided which connects to one side of the circuit substrate 54 and which provides an enclosed region within the internal space of the housing 20.

Figure 4 shows the housing 20 in more detail. The baseplate 26 and the lower cover 44 connect together to define the space in which the air quality sensing device 16 is receivable. The lower pedestal interface 36b is also shown, indicating how the fasteners 42 easily allow for release of the housing 20 from the mount 14, and by definition allow for easy release of the air quality sensing device 16.

Figures 5A and 5B show the air quality sensing device 16 as a replaceable unit which can be removed from the housing 20. This unitary nature allows for the air quality sensing 30 device 16 to be rapidly swapped during repair or maintenance processes, so that there is no significant downtime when there are problems with the sensors. The air-calming element 52 can be seen in Figure 5A having a baffle element 62 in a central position which positionally corresponds with a position of the air inlet 28 of the lower cover 44, so that ventilation must occur through the mesh portion. A secondary air inlet 32 can be seen on the side of the air quality sensing device 16, which is formed by the enclosure moulding 60.

The position of the enclosure moulding 60 can also be seen on the rear of the air quality sensing device 16, and the enclosure moulding 60 is releasably engagable with the first part 50, for instance, by using a slidable engagement with retaining screws 64.

The enclosure moulding 60 protects a particulate sensor 66 which is connected to the circuit substrate 54, shown removed from the circuit substrate 54 in Figures 6 and 7 for ease. The enclosure moulding 60 creates a seal around the particulate sensor 66 to the exterior of the air quality sensing apparatus 10 to the secondary air inlet 32. The particulate sensor 66 includes a fan, and therefore the isolation of the particulate sensor 66 from the main volume of the housing 20 prevents disruption of the airflow in the main volume by the particulate sensor 66. Figure 7 also shows how the main casing 50 of the two-part casing 48 is fixed to the air-calming element 52 via a plurality of fasteners.

Figures 8A and 8B show the first and second sides 68a, 68b of the circuit substrate 54. The first side 68a, which is shown in Figure 8A, and which forms the in-use downward-facing side, includes the majority of the air quality sensors 56. A plurality of said air quality sensors 56 is provided to allow for cross-sensitivity data to be accumulated to identify the concentrations of otherwise unknown gases within the air quality sensor apparatus 10.

In other words, the plurality of air quality sensors 56 comprises a plurality of different gas sensors, the plurality of gas sensors each have a primary gas sensitivity and at least one secondary gas sensitivity, the air quality sensing apparatus 10 being configured to determine at least one gas concentration which is not related to any of the primary gas sensitivities based on the at least one secondary gas sensitivities of the plurality of gas sensors 56. For cross-sensitivity data to be viable, it is preferred that at least four said air quality sensors 56 are provided, and eight dedicated sensor packages are illustrated in the present embodiment of the invention. Additional types of air quality sensor could also be provided. An onboard processor 70 may also be provided which allows for the calculation of the cross-sensitivity information, and/or for any processing which may be required by the air quality sensing apparatus 10. Equally, a wireless communicator could be provided to allow for off-board processing and/or communication with other apparatuses or systems.

The second side 68b of the circuit substrate 54 is where the particulate sensor 66 is provided, shown in Figure 8B, which allows for more straightforward isolation thereof 5 relative to the other air quality sensors 56.

The circuit substrate 54 itself may be provided as a modular circuit substrate having a plurality of interconnectable substrate portions 72a, 72b, 72c. Three said substrate portions 72a, 72b, 72c are shown; however, since the substrate couplings 74 are generic across the substrate portions 72a, 72b, 72c, it will be apparent that the circuit substrate 54 could be scaled according to the user's needs, which may be scalable to the number of air quality sensors 56 desired.

The internal construction of the air quality sensing apparatus 10 is detailed in Figures 9A to 11B, with Figures 9B, 10B, and 11B respectively showing the cross-sections of the inset Figures 9A, 10A, and 11A.

Figure 9B shows the isolation of the particulate sensor 66 from the rest of the internal volume of the housing 20. The enclosure moulding 60 provides a trumpet-shaped seal to the air inlet and air outlet of the particulate sensor 66, which both communicate with the secondary air inlet 32 of the air quality sensing apparatus 10 Figure 9B also shows the in-use positions of the air quality sensors 56. The first side 68a of the circuit substrate 54 is a downward-facing side in-use, meaning that the air quality sensors 56 hang down from the circuit substrate 54. For ease of maintenance, the air quality sensors 56 as shown are plug-fit sensors into corresponding receivers of the circuit substrate 54. However, this means that the air quality sensors 56 can dislodge under gravity during use if the plug-fit is imperfect. For this reason, there is provided a failsafe support 76 for the air quality sensors 56, the failsafe support 76 being positioned spaced apart from the downward-facing side of the circuit substrate 54 to support the at least one air quality sensor 56 if the at least one air quality sensor 56 becomes partially dislodged from the circuit substrate 54 during use.

In the embodiment shown, the failsafe support 76 may be integrally formed with the air-30 calming element 52, since this forms the downward enclosure of the air quality sensing device 16. However, it will be appreciated that the failsafe support 76 could be provided as a separate component within the air quality sensing device 16.

On the other hand, the particulate sensor 66 is shown to be positioned on the opposite side of the circuit substrate 54 to the air quality sensors 56, that is, on the second side 5 68b thereof The second side 68b is an upward-facing side of the circuit substrate 54.

Figure 9B also shows how the perimetric lip 58 extends to the outside of the housing 20, thereby enabling internal illumination to be visible to occupants of the room in which the air quality sensing apparatus 10 is installed.

Furthermore, the slope of the lower cover 44 can be seen in more detail. Apertures 78 10 of the air-calming element 52 are positioned vertically above the sloped surfaces 80 of the lower cover 44, so that dust falling through the air-calming element 52 will land on the sloped surfaces 80 and fall through the air inlet 28 under gravity.

Figures 10A to 11B show the relationship between the air quality sensing device 16 and the mount 14 in more detail. The mount 14 itself is hollow, which allows the electrical 15 connector 38 to extend therethrough, being connected to the coupling 40 of the baseplate 26, which is received by the lower pedestal interface 36b.

The hollow nature of the mount 14 not only allows for the electrical connection to be made, but also provides an airflow path up through the mount 14. At least one convection current vent 82 is provided at a top end of the mount 14. Slight heating of the air within the internal volume of the housing 20 by the components of the circuit substrate 54 will lead to slow convection currents forming. These currents will largely be generated above the downward-facing air quality sensors 56, therefore not significantly disturbing the air being sensed. Advantageously, convection currents may entrain dust which is also ejected from the convection current vents 82. Since the mount 14 is elongate, ejection from the convection current vents 82 will disperse the dust well away from the lower parts of the air quality sensing apparatus 10, reducing dust ingress via the air inlet 28.

Figure 11B in particular highlights the ease with which the air quality sensing device 16 can be removed from the mount 14; the two fasteners 42 can be seen extending through the lower pedestal interface 36b, and interconnecting the baseplate 26 and the main casing 50 of the air quality sensing device 16. If the lower cover 44 has been removed, then removal of these fasteners 42 will allow the air quality sensing device 16 to be detached from the baseplate 26. A user can do this very simply, since the fasteners 42 are, whilst obscured from view, easily accessible since the elongate mount 14 spaces the baseplate 26 from the ceiling 12. Whilst screw-threaded fasteners are illustrated, it will be apparent to the skilled person that alternative arrangements are available, such as clip fasteners, mechanical interlocks, or combinations of fasteners and clips.

It will be appreciated that the depicted embodiment is a ceiling-mounted apparatus, but it will be apparent that a mount could be constructed which has a turn or bend in it, and therefore which allows the air quality sensing device to be wall-mounted without altering the downward-facing nature of the first side of the circuit substrate.

Similarly, a free-standing unit could be considered, in which a support is provided which stands on the ground, with a top end thereof curving back on itself, for instance, in a 'U'-shape, to again allow for the air quality sensing device to have a downward-facing set of air quality sensors. This would be similar in construction to a freestanding lamp.

Whilst a modular mount is described above, the mount could of course be provided as a 15 unitary component directly installable to a surface in a room. Indeed, the whole apparatus could be provided as a unitary device, in which the air quality sensing device was not easily extractable.

The air inlet in the lower cover as illustrated is merely one aesthetic arrangement possible which also encourages dust ejection. It will be appreciated that other air inlet 20 configurations are feasible, for instance, where a plurality of air inlets are provided on a downward-facing surface of the apparatus.

It will be appreciated that the housing for the air quality sensing device is dimensioned according to the size of the circuit substrate. As noted above, the circuit substrate has been constructed in a manner enabling modular extension, and therefore it is clear that 25 different housing configurations and dimensions will be available The present air quality sensing apparatus therefore has several advantageous features. The presence of downward-facing air quality sensors allows said sensors to be passively facing the main body of air in a room, whilst also allowing for dust to naturally fall away from the sensor surfaces. This leads to reduced maintenance requirements, and consequential improved accuracy of measurements.

The suspension of the circuit substrate within the housing of the air quality sensing apparatus also allows for both sides of the circuit substrate to be used, and the opposite, upward-facing side, can be used for mounting a particulate sensor, or similar sensor which requires an onboard fan. This arrangement allows for such a sensor to be physically isolated from the remaining air quality sensors, preventing airflow disturbances from the particulate sensor fan affecting the air composition at the other sensors.

Furthermore, the provision of the easy-release connection between the air quality sensing device and the mount allows for quick swaps of air quality sensing devices, 10 allowing for repairs and maintenance to be performed remote to the air quality sensing apparatus.

It is therefore possible to provide an air quality sensing apparatus with many advantages over existing sensing systems.

The words comprises/comprising' and the words 'having/including' when used herein 15 with reference to the present invention are used to specify the presence of stated features, integers, steps, or components, but do not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from 25 the scope of the invention as defined herein.

Claims

Claims 1. An air quality sensing apparatus comprising: a housing having an air inlet to an internal volume; an attachment means for attaching the housing to a ceiling or wall and a circuit substrate positioned in the internal volume of the housing, the circuit substrate having at least one air quality sensor mounted thereon; the circuit substrate being positioned within the housing such that the at least one air quality sensor is on an in-use downward-facing side of the circuit substrate when the housing is mounted to a ceiling or wall via the attachment means.
2. An air quality sensing apparatus as claimed in claim 1, wherein the housing comprises a lower cover receivable over the in-use downward-facing side of the circuit substrate, the lower cover having a sloped surface towards the air inlet.
3. An air quality sensing apparatus as claimed in claim 1 or claim 2, wherein the circuit substrate is provided as an air quality sensing device releasably engageable with 15 the housing.
4. An air quality sensing apparatus as claimed in any one of the preceding claims, further comprising a failsafe support for at least one air quality sensor, the failsafe support being positioned spaced apart from the downward-facing side of the circuit substrate to support the at least one air quality sensor if the at least one air quality sensor becomes partially dislodged from the circuit substrate during use.
5. An air quality sensing apparatus as claimed in claim 4, wherein the failsafe support is formed as a perimetric frame for the at least one air quality sensor.
6. An air quality sensing apparatus as claimed in any one of the preceding claims, further comprising an air-calming element in the housing spaced apart from the 25 downward-facing side of the circuit substrate.
7. An air quality sensing apparatus as claimed in any one of the preceding claims, wherein the attachment means comprises an elongate support member engageable with a ceiling.
8. An air quality sensing apparatus as claimed in any one of the preceding claims, wherein a plurality of said air quality sensors is provided.
9. An air quality sensing apparatus as claimed in claim 8, wherein the plurality of air quality sensors comprises a plurality of different gas sensors, the plurality of gas sensors each have a primary gas sensitivity and at least one secondary gas sensitivity, the air quality sensing apparatus being configured to determine at least one gas concentration which is not related to any of the primary gas sensitivities based on the at least one secondary gas sensitivities of the plurality of gas sensors.
10. An air quality sensing apparatus as claimed in any one of the preceding claims, 10 further comprising an onboard processor.
11. An air quality sensing apparatus comprising: a housing having an internal volume, the housing having a first air inlet communicable with the internal volume and a second air inlet communicable with the internal volume; and a circuit substrate positioned in the internal volume of the housing, the circuit substrate having a first air quality sensor mounted on a first side of the circuit substrate so as to be communicable with the first air inlet, and a second air quality sensor mounted on a second side of the circuit substrate so as to be communicable with the second air inlet; the first and second air quality sensors being isolated from one another within the internal volume of the housing.
12. An air quality sensing apparatus as claimed in claim 11, wherein a plurality of first air quality sensors is provided.
13. An air quality sensing apparatus as claimed in claim 11 or claim 12, wherein the 25 second air quality sensor is a particulate sensor.
14. An air quality sensing apparatus as claimed in claim any one of claims 11 to 13, wherein the second air quality sensor is releasably engagable from the circuit substrate from an exterior of the housing.
15. An air quality sensing apparatus as claimed in any one of claims 11 to 14, wherein the second air quality sensor is engaged with the housing via an enclosure moulding.
16. An air quality sensing apparatus as claimed in claim 15, wherein the enclosure moulding is releasably engagable with the housing.
17. An air quality sensing apparatus as claimed in any one of claims 11 to 16, wherein there is no fan associated with the first air inlet.
18. An air quality sensing apparatus comprising: an air quality sensing device comprising at least one air quality sensor; and a mount for securely mounting the air quality sensing device to a surface in a 10 room, the mount comprising: a device coupling for providing electrical connection between the mount and the air quality sensing device; a support member engageable between the device coupling and the surface; and a securing means for providing a secure connection between the support member and the air quality device when engaged with the device coupling.
19. An air quality sensing apparatus as claimed in claim 18, wherein the support member is an elongate support member.
20. An air quality sensing apparatus as claimed in claim 18 or claim 19, wherein the 20 support member comprises a convection current vent.
21. An air quality sensing apparatus as claimed in any one of claims 18 to 20, wherein the device coupling is formed as a base plate engageable with the air quality sensing device.
22. An air quality sensing apparatus as claimed in any one of claims 18 to 21, further 25 comprising a cover, the cover forming a housing for the air quality sensing device with the device coupling.
23. An air quality sensing apparatus as claimed in any one of claims 18 to 22, wherein the housing is at least in part light-transmissible, and further comprising at least one status-indicator light in the housing.
24. An air quality sensing apparatus as claimed in any one of claims 18 to 23, wherein 5 the support member comprises a castellated surface-connector directly engagable with the surface to which the mount is connected.
25. An air quality sensing apparatus as claimed in any one of claims 18 to 24, wherein the mount is provided as a modular kit of parts.