GB2539449A - Monitor for air quality - Google Patents

Abstract

An air quality monitor (10) comprising a housing (14), within which are electronic components (25) including sensors (36, 37, 38) at least for temperature, humidity, particulates, and volatile organic compounds (VOCs), though other sensors such as CO2 or light intensity may be optionally added, a processor (42) to deduce a measure of indoor air quality from the measurements from the sensors, and a fan (26) to draw ambient air into and through the housing; and also includes a means (44) for local wireless networking (Wifi RTM) communication. The particulates sensor (36) may detect particles of mean size less than 2.5 pm. The Wifi RTM means (44) may enable data about external air quality and weather to be obtained from the Internet or transmit information or suggestions for air quality improvement to a remote server or mobile device. The housing (14) may define at least one aperture (24) for inflow of air, and a bell-shaped outflow duct (18), each aperture (24) being concealed behind a baffle (15). The device may have both a mains power connection and a battery power supply allowing for portability between multiple deployment locations. The housing of the monitor is constructed to direct air-flow through the device.

Description

Intellectual Property Office Application No. GII1510558.8 RTM Date:6 January 2016 The following terms are registered trade marks and should be read as such wherever they occur in this document: Sharp (page 4) ST Microelectronics (Page 4-5) Wi-Fi (Pages 5 & 10) Intellectual Property Office is an operating name of the Patent Office www.gov.uk /ipo Monitor for Air Quality This invention relates to a monitor for air quality for use for example in a domestic or office environment.

People typically spend a high proportion of their time indoors, for example in the home or in offices. Efforts are currently being made to improve the energy efficiency of homes, and this includes taking steps to minimise draughts. However, this may have the consequence that there is less air exchange between indoor air and outdoor air, and since many pollutants are generated within the home environment, indoor air quality can become poor. This can cause asthma in some people. There is a recognition that ventilation is a requirement in all such buildings. It has also been suggested that air quality should be monitored, for example in a residential environment.

According to the present invention there is provided an air quality monitor, the monitor comprising a housing, within which are sensors at least for temperature, humidity, particulates, and volatile organic compounds (VOCs); the monitor also comprising a processor to deduce a measure of indoor air quality from the measurements from the sensors, and a fan to draw ambient air into and through the housing; the monitor also comprising means for local wireless networking (Wifi) communication.

The particulates sensor may detect particles of mean size less than 2.5 pm, and this may be referred to as a PM2.5 sensor. The particulates sensor may monitor particles of a different size, for example smaller than 10 µm in which case it may be referred to as a PM10 sensor.

The local network will typically include a router that connects to the Internet; and the Wifi communication is desirably arranged to enable the monitor to download information about external air quality and weather, from an Internet source (such as the Meteorological Office). It is preferably also arranged to enable the monitor to send information about the monitored air quality to a local device such as a mobile phone, and/or to transmit such information to a remote server over the Internet.

The monitor may therefore be arranged to provide a notification or an alert to a user, for example to their mobile phone (with a suitable software application installed on the mobile phone), so the mobile phone can display current information about indoor air quality, or can provide a warning if the indoor air quality becomes worse than a pre-set threshold. The monitor may also provide suggestions to the user for improving indoor air quality, and such suggestions may take into account the downloaded information about external air quality and weather. The monitor may be arranged to provide an email report to the user of the variations of internal air quality, for example on a daily basis.

Preferably the monitor also includes a display to indicate current level of air quality, for example by means of a light indicating different levels of air quality by different colours such as green, orange or red.

Where the data is transmitted to a remote server, the user may therefore be able to download historic data, to observe trends.

Preferably the monitor includes a battery, in particular a rechargeable battery, and can preferably also be powered from the mains. The monitor may therefore normally be used under mains power, but if the user wishes to monitor air quality in another place the monitor may be used for a period such as 24 hours or 48 hours relying only on battery power. Hence the user can monitor indoor air quality in various different rooms in a house. The mobile phone application would preferably enable the change of room to be recorded, so that data for different rooms can be stored separately, for example on the remote server. Indeed the monitor may be arranged to send an enquiry to the associated mobile phone whenever the mains power supply is disconnected or reconnected, to ask the user to provide identification of the place or room where measurements are now to be made.

The provision of the fan has the benefit of actively drawing air through the monitor, rather than relying on diffusion. A further consideration is to suppress dust from settling in the monitor. A suitable design for the housing includes one or more apertures in a side wall of the housing for inflow of air, and an outflow duct for air that has passed through the monitor. The outflow duct may be at the top of the housing, and arranged so the outflowing air flows upwardly. The housing may also include a baffle outside at least part of the housing, spaced apart from the side wall in which the aperture or apertures are defined so that the apertures are concealed behind the baffle. The baffle may be connected to the remainder of the housing along only one edge of the baffle, or may be clipped to the remainder of the housing at each edge of the baffle. The apertures may be vertical slots through the side wall. A preferred embodiment has a housing of a generally cylindrical shape but gradually decreasing in width at the top and bottom, and which curves at the top into an outflow duct. The outflow duct may taper like a bell, or may be of substantially constant width.

The monitor may include sensors for other parameters, such as carbon dioxide and light intensity.

The invention will now be further and more particularly described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 shows a side view of a monitor; Figure 2 shows a cross-sectional view on the line 2-2 of figure 1; Figure 3 shows a sectional view in a vertical plane, on the line 3-3 of figure 2; Figure 4 shows a perspective view of electronic components inside the monitor; Figure 5a and 5b show measurements from the monitor of figures 1-4 as displayed on a mobile phone; and Figure 6 shows a sectional view equivalent to that of figure 2 through a modification to the monitor of figure 1.

Referring now to figure 1, an air quality monitor 10 comprises an upper housing 12 and a lower housing 13 which together define a generally cylindrical casing 14 and a curved baffle 15. The casing 14 curves inward at the top and the bottom, and the baffle 15 extends approximately parallel to the outer surface of the casing 14, but is slightly less tall. As shown in figure 2, which shows a sectional view looking upward on the line 2-2 of figure 1, the baffle 15 is spaced away from the outer surface of the casing 14 so as to define an airflow channel 16, but at one end the baffle 15 is integral with the casing 14 and merges with the cylindrical surface of the casing 14, so there is a smooth curve between the outer surface of the baffle 15 and the outer surface of the casing 14 where they join.

Referring also to figure 3, the casing 14 curves inwardly at the top and bottom to define bell shaped portions 18 and 19 respectively. At the top, the bell shaped portion 18 tapers to an opening 20, whereas at the bottom, the bell shaped portion 19 tapers to an integral closure plate 22. A portion of the wall of the casing 14 which faces the baffle 15 defines several longitudinal slots 24, there being eight in this example. Within the lower housing 13 is an electronics module 25 at the top of which is a fan 26 (the module 25 and the fan 26 are shown schematically), and a bell-shaped chimney 28 is mounted on top of the fan 26, the top end of the chimney 28 tapering down to the opening 20, so the top of the chimney 28 is connected to the bottom end of the bell-shaped portion 18. The chimney 28 in combination with the bell-shaped portion 18 consequently define a smooth-walled outflow path for air from the fan 26, while the air enters the casing 14 via the airflow channel 16 and the longitudinal slots 24. The outflow path is sufficiently wide that it does not restrict the airflow from the fan 26.

A low voltage DC socket 30 (shown in broken lines in figure 3) enables the air quality monitor 10 to be powered by the mains, through a conventional mains/low voltage DC converter. The monitor 10 is also provided with a push-button on/off switch 32 mounted on the integral closure plate 22, so this switch 32 is hidden in normal use.

Referring now to figure 4, this shows a perspective view of the electronics module 25. The electronics module 25 consists of a main printed circuit board 34 to which all the sensors are connected. Behind the printed circuit board 34, as shown, is a PM2.5 sensor 35 to detect small particles less than 2.5 pm in size, on top of which is the fan 26 (shown in figure 3); air enters the PM2.5 sensor 35 through an opening 36 in the underside of the sensor 35, being drawn in by the fan 26, to emerge through the chimney 28. A light sensor 37 is mounted on a cable, being shown at one side of the PM2.5 sensor 36, and a sensor 38 for temperature and relative humidity is mounted so as to be spaced out from the main printed circuit board 34. A VOCs sensor 39 is also mounted on the printed circuit board 34, so the sensors 38 and 39 are exposed to ambient air flowing from the longitudinal slots 24 to the opening 36. The orientation of the electronics module 25 within the casing 14 is such that the sensor 38 for temperature and relative humidity and the VOCs sensor 39 are both near to the slots 24 that are closest to the free end of the baffle 15 (i.e. the right-hand slots 24 as shown in figure 2). The light sensor 37 is arranged to sense light entering the slots 24. In addition a battery 40 is clipped onto the far side of the PM 2.5 sensor 35.

It will also be appreciated that the main printed circuit board 34 is oriented vertically. This makes it easier to ensure the sensors 38 and 39 are close to the slots 24.

By way of example the PM2.5 sensor 35 may be a model DN7C3CA006 from Sharp, which incorporates a virtual impactor to separate particles less than 2.5 pm from larger particles, and which then uses a light emitter in combination with a photodetector to detect the number of the small particles, and which is suitable for measurements over the range 25 to 500 pg/m3. The sensor 38 for temperature and relative humidity may for example be a model HTS221 from ST Microelectronics, which provides measurement information through a digital serial interface, the sensing element for humidity consisting of a polymer dielectric planar capacitor sensitive to variation in relative humidity; this device also includes a temperature sensor. The VOCs sensor 39 may for example be an Applied Sensor iAQ-core module, which uses micro-machined metal oxide semiconductor technology to detect a broad range of VOCs, which is converted into an equivalent concentration of carbon dioxide; this sensor is able to detect reducing compounds such as alcohols, aldehydes, aliphatic and aromatic hydrocarbons, amines, ketones and organic acids, as well as carbon monoxide, methane and liquid petroleum gases.

The printed circuit board 34 carries a processor 42 for receiving and analysing the signals from the sensors 35, 37, 38 and 39, and also includes a Wifi communication module 44; these components are shown schematically. This enables the data from the air quality monitor 10 to be transmitted to a router and hence to a smartphone or mobile phone 50 which runs a suitable software application. The processor 42 is arranged to calculate an overall measure of air quality, iAQ, that takes into account the data from all of the sensors.

One such mobile phone 50 is shown in figures 5a and 5b to which reference is now made. As shown in figure 5a, the data from the air quality monitor 10 may be displayed in words, as indicated at 51, representing the overall measure of air quality; the data relating to overall air quality, iAQ, and in addition the data from one or more of the individual sensors such as relative humidity, rH, and temperature, T, may be displayed graphically by means of appropriate icons, as indicated at 52. The screen also provides for additional details about each displayed parameter, by tapping the appropriate icon as indicated at 53, and a menu button 54 for other alternatives. Referring to figure 5b, an alternative display 55 shows the variation in a measured parameter, such as temperature, T, over a period of time such as 24 hours, shown as a graph. The graph may be also annotated to show an upper threshold 56 above which the parameter is considered high, and may also show a threshold 57 below which the parameter is considered low. This display is shown for temperature, T, but it will be appreciated that a similar display may be provided for any one of the measured parameters or for air quality, iAQ, and in each case one or more threshold values may also be shown.

The user would have the option to change the display, and indeed to change the parameters that are displayed. As indicated above, typically the display would show indoor temperature, T, in °C, with an option to display the information in °F; and would display relative humidity, rH, as a percentage. If the level of particulates, PM2.5, is shown, this would typically be displayed as an index for example between 1 and 10; and similarly if the concentration of volatile organic compounds, VOCs, is shown, this would typically be displayed as an index which might be between 1 and 100. The overall measure of air quality may be indicated in words, as at 51, and as an icon, as at 52; but may also be displayed for example by changing the colour of the home screen of the mobile phone 50.

The communication between the air quality monitor 10 and a router also enables the air quality monitor 10 to transmit the measured data to an external server if it is to be stored; and enables the air quality monitor 10 to obtain data from an external source, for example finding data on external weather and external air quality from an organisation such as the Meteorological Office. As indicated in figure 5a at 58, the display may also suggest actions that may be taken by the user. In this example the suggestion is to "open a window": this might be appropriate if the indoor level of VOCs is high and if the external air quality is good, so there is low external pollution. As another example, if the measured value of relative humidity, rH, is high the suggestion might be "switch on dehumidifier" or might be "open a window"; but the latter would be inappropriate if the data from the external organisation suggested that the weather conditions were heavy rain.

Where the measurement data is stored on a device separate from the air quality monitor 10, for example on an external server, then it is clearly appropriate to associate the stored data with an indication of the location where the data is obtained. So for example when setting up the air quality monitor 10 in conjunction with the mobile phone 50, the user may be prompted to give a name to the room in which the monitor 10 is installed, for example "living room". This would be the room in which the monitor 10 is connected to mains power via the socket 30. Power would not be taken from the battery 40 under those circumstances. If the user wishes to monitor conditions in a different room on a temporary basis, the monitor 10 can be disconnected from the mains power, and can operate on power from the battery 40, for example for a period of 24 hours or 48 hours. Consequently, when the user disconnects the monitor from the mains power, the display of the mobile phone 50 would request the user to identify the room in which the monitor 10 is now to be placed, for example "bedroom". When the user reconnects the monitor 10 to mains power, the display would again request the user to identify the room in which the monitor 10 is to operate.

Where the measurement data is stored on a device separate from the air quality monitor 10, for example on an external server, then the user would also be provided with the option, using the display of the mobile phone 50, to display variation in a measured parameter over a much longer period, for example over a six-month or twelve-month period, by downloading the stored data from the separate device.

It will be appreciated that the monitor 10 described above is only by way of example, and that it may be modified in various ways while remaining within the scope of the claims. For example the air quality monitor 10 might be of a different size or shape to that described; it may have additional sensors, which may sense other parameters of relevance to air quality. It will also be appreciated that the location of the sensors within the air quality monitor 10 may differ from that shown in figure 4, as long as the sensors for measuring properties of the air are exposed to ambient air; this is particularly pertinent as regards sensors for relative humidity, the concentration of VOCs and the concentration of particulates. In another modification the air outflow from the fan may flow along an outflow duct of substantially uniform width; in another modification the outflow duct 18 may extend to reach the outlet from the fan 26, so that no separate chimney 28 would be provided.

In one modification the chimney 28 is provided with several vertical slots around its circumference, and with inwardly-projecting fins at the top of the chimney 28 adjacent to the opening 20, and is enclosed within a sleeve of porous foam. The inwardly-projecting fins are sufficiently thin not to have a detrimental effect on the airflow, but ensure a child can't poke the fan 26 with his finger. The sleeve of porous foam and the vertical slots through the chimney 28 suppress the transmission of sound from the fan 26.

In another modification the housing 14 is provided with a small hole, for example a hole of diameter 2 mm, with a transparent plastic cover, and the light sensor 37 is clipped to the inside of the housing 14 to receive light that passes through this hole. This small hole may be in a region of the housing 14 that is not covered by the baffle 15. This can provide greater light intensity at the sensor 37 than relying on light that has entered the housing 14 through the slots 24, as described above.

Referring now to figure 6 there is shown a horizontal sectional view, equivalent to the view of figure 2, of a modified air monitor 60; as with figure 2, the electronics module 25 is not shown. The air monitor 60 consists of a housing 64 and a baffle 65 of the same external appearance as those of the air monitor 10. In this case the housing 64 consists of an upper housing 62 and a lower housing 63 which together define the generally cylindrical casing 64, and these parts are held together by locating pins 66, clips 67 and screws 68. The curved baffle 65 is a single component over its entire height. As in the monitor 10, the casing 64 curves inward at the top and the bottom, and the baffle 65 extends approximately parallel to the outer surface of the casing 64, but is slightly less tall, being spaced away from the outer surface of the casing 64 by vertical fins 70 and horizontal fins 71 so as to define an airflow channel 72.

The housing 64 defines a rectangular aperture of the same height as the baffle 65 with opposed edges 73 and 74, and one edge of the baffle 65 is clipped onto the edge 73 so there is a smooth curve between the outer surface of the baffle 65 and the outer surface of the casing 64 where they meet, and so the baffle 65 completely blocks this aperture. Near the opposite edge of the baffle 65 are ratchet-shaped clips 75 that project through corresponding slots in the wall of the housing 64 and so secure the baffle 65 onto the outside of the housing 64.

The housing 64 defines a single rectangular aperture 77 around an arc of about 40° of its circumference and extending over the middle third of the height of the housing 64, between the locations of the screws 68. This aperture 77 allows air to flow into the housing 64, and takes the place of the vertical slots 24 in the air monitor 10. This aperture 77 is concealed by the baffle 65.

The air monitor 60 operates in substantially the same way as the air monitor 10 described above, as the only difference as regards the airflow is the provision of the single aperture 77 in place of the vertical slots 24. The electronics module 25 includes a fan 26 which draws air in through the airflow channel 72 and so through the aperture 77 into the housing 64; and the air is expelled through the opening 20 at the top as described above.

Other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features that are already known and which may be used instead of, or in addition to, features described herein. Features that are described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, features that are described in the context of a single embodiment may also be provided separately or in any suitable sub-combination.

It should be noted that the term "comprising" does not exclude other elements or steps, the term "a" or "an" does not exclude a plurality, a single feature may fulfil the functions of several features recited in the claims and reference signs in the claims shall not be construed as limiting the scope of the claims. It should also be noted that the Figures are not necessarily to scale; emphasis instead generally being placed upon illustrating the principles of the present invention.

Claims (14)

1. Claims 1. An air quality monitor, the monitor comprising a housing, within which are sensors at least for temperature, humidity, particulates, and volatile organic compounds (VOCs); the monitor also comprising a processor to deduce a measure of indoor air quality from the measurements from the sensors, and a fan to draw ambient air into and through the housing; the monitor also comprising means for local wireless networking (Wifi) communication.
2. 2. An air quality monitor as claimed in claim 1 wherein the particulates sensor detects particles of mean size less than 2.5 pm.
3. 3. An air quality monitor as claimed in claim 1 or claim 2 wherein the Wifi communication means is arranged to enable the monitor to download information about external air quality and weather, from a data source on the Internet.
4. 4. An air quality monitor as claimed in any one of the preceding claims wherein the Wifi communication means is arranged to enable the monitor to transmit information about the monitored air quality to a remote server over the Internet.
5. 5. An air quality monitor as claimed in any one of the preceding claims wherein the Wifi communication means is arranged to enable transmission of information to, and receipt of information from, a local electronic device such as a mobile phone.
6. 6. An air quality monitor as claimed in claim 5 when dependent on claim 3, wherein the monitor is arranged to transmit data to the local electronic device, the data incorporating suggestions to the user for improving indoor air quality, the suggestions taking into account the downloaded information about external air quality and weather.
7. 7. An air quality monitor as claimed in any one of the preceding claims comprising means for connection to mains electricity to provide power, and also comprising a battery.
8. 8. An air quality monitor as claimed in any one of the preceding claims wherein the housing includes a side wall in which are defined at least one aperture for inflow of air, and the housing also defines an outflow duct for air that has passed through the monitor, the outflow duct being at the top of the housing, and arranged so the outflowing air flows upwardly, and the housing also including a baffle outside the housing spaced apart from the side wall in which each aperture is defined, so that each aperture is concealed behind the baffle.
9. 9. An air quality monitor as claimed in claim 8 wherein the baffle is connected to the remainder of the housing along only one edge of the baffle.
10. 10. An air quality monitor as claimed in claim 8 wherein the baffle is clipped to the remainder of the housing at or adjacent to each edge of the baffle.
11. 11. An air quality monitor as claimed in any one of claims 8 to 10 wherein the housing is of a generally cylindrical shape but gradually decreasing in width at the top and bottom, and which curves in at the top to form the outflow duct.
12. 12. An air quality monitor as claimed in any one of claims 8 to 11 wherein the fan communicates with the outflow duct such that the path for outflowing air from the fan has a first portion which becomes narrower and a second portion which becomes wider, both the first portion and the second portion having a bell-shaped taper.
13. 13. An air quality monitor as claimed in any one of the preceding claims also including sensors for other parameters, such as carbon dioxide and light intensity.
14. 14. An air quality monitor substantially as hereinbefore described with reference to, and as shown in, figures 1 to 4 or figure 6 of the accompanying drawings.