Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
AIR PURIFIER WITH POLLUTION SENSING
Document Type and Number:
WIPO Patent Application WO/2017/167671
Kind Code:
A1
Abstract:
A fluid sensor device (10) is disclosed that comprises a chamber (20) having a first inlet (21), a second inlet (23) and an outlet (25); a valve arrangement (30, 30', 30") configured to fluidly connect the first inlet to the outlet in a first configuration; and fluidly connect the second inlet to the outlet in a second configuration; a controller (40) adapted to switch the valve arrangement between the first configuration and the second configuration; and a sensor arrangement (50) in the chamber arranged to detect a first pollutant level in a fluid flowing through the chamber in the first configuration and to detect a second pollutant level in a fluid flowing through the chamber in the second configuration. Such a device for instance may be used to determine the efficiency of a pollutant removal structure such as a filter of an air purifier by guiding a sample of the 'dirty' air through the first inlet and a sample of the air purified by the pollutant removal structure through the second inlet. An air purifier system including such a fluid sensor device (10), a method (300) of operating such an air purifier system and a computer program product for implementing such a method are also disclosed.

Inventors:
LI, MingDong (Jeffrey) (Building 5, 5656 AE Eindhoven, 5656 AE, NL)
KELLY, Declan Patrick (Building 5, 5656 AE Eindhoven, 5656 AE, NL)
SCHEJA, Michael Martin (Building 5, 5656 AE Eindhoven, 5656 AE, NL)
Application Number:
EP2017/057140
Publication Date:
October 05, 2017
Filing Date:
March 27, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
KONINKLIJKE PHILIPS N.V. (High Tech Campus 5, 5656 AE Eindhoven, 5656 AE, NL)
International Classes:
G01N33/00; B01D46/00; F24F3/16
Foreign References:
US20110072883A12011-03-31
DE29816225U11999-08-12
US20060108221A12006-05-25
CN102019102A2011-04-20
Attorney, Agent or Firm:
FREEKE, Arnold et al. (High Tech Campus Building 5, 5656 AE Eindhoven, 5656 AE, NL)
Download PDF:
Claims:
CLAIMS

1. A fluid sensor device (10) comprising:

a chamber (20) having a first inlet (21), a second inlet (23) and an outlet (25); a valve arrangement (30, 30', 30") configured to:

fluidly connect the first inlet to the outlet in a first configuration; and fluidly connect the second inlet to the outlet in a second configuration;

a controller (40) adapted to switch the valve arrangement between the first configuration and the second configuration; and

a sensor arrangement (50) in the chamber arranged to detect a first pollutant level in a fluid flowing through the chamber in the first configuration and to detect a second pollutant level in a fluid flowing through the chamber in the second configuration.

2. The fluid sensor device (10) of claim 1, wherein the valve arrangement comprises a first valve (30, 30')·

3. The fluid sensor device (10) of claim 2, wherein the first valve (30) is rotatably mounted in the chamber (20). 4. The fluid sensor device (10) of claim 2, wherein the valve arrangement further comprises a second valve (30"), wherein:

the first valve (30') is configured to block the first inlet (21) in the first configuration and to unblock the first inlet in the second configuration; and

the second valve (30") is configured to unblock the second inlet (23) in the first configuration and to block the second inlet in the second configuration.

5. The fluid sensor device (10) of any of claims 1-4, wherein the sensor arrangement (50) comprises a sensor in the outlet (25). 6. An air purifier system comprising; an air purifier (100) comprising an air purification path (105, 105') extending from an air purification inlet (101) to an air purification outlet (103);

an air purification arrangement (110) in the air purification path between the air purification inlet and the air purification outlet; and

the fluid sensor device (10) of any of claims 1-5, wherein the first inlet (21) is an ambient air inlet and the second inlet (23) is fluidly connected to a section (105') of the air purification path in between the air purification arrangement and the air purification outlet; and

a processor (120) communicatively coupled to the sensor arrangement (50), the processor being arranged to determine an efficiency of the air purification arrangement from the first pollutant level and the second pollutant level detected with the sensor arrangement.

7. The air purifier system of claim 6, wherein the first inlet (21) is fluidly connected to a section (105) of the air purification path in between the air purification inlet (101) and the air purification arrangement (1 10).

8. The air purifier system of claim 6 or 7, wherein the processor (120) is integral to the air purifier (100) or is included in a processing device (200) communicatively coupled to the air purifier.

9. The air purifier system of any of claims 6-8, further comprising a sensory output device (130), wherein the processor (120) is adapted to provide the sensory output device with a control signal for generating a sensory output indicative of the efficiency of the air purification arrangement (110).

10. The air purifier system of any of claims 6-9, wherein the processor (120) arranged to determine an efficiency of the air purification arrangement (110) from the first pollutant level and the second pollutant level detected with the sensor arrangement (50) is adapted to determine a clean air delivery rate of the air purifier (100) from the first pollutant level and the second pollutant level.

11. The air purifier system of claim 10, wherein the processor (120) is further adapted to compare the determined clean air delivery rate against a benchmark clean air delivery rate and to generate a warning signal if a deviation of the determined clean air delivery rate from the benchmark clean air delivery rate exceeds a defined threshold.

12. A method (300) of operating the air purifier system of any of claims 6-11, the method comprising:

switching (303) the valve arrangement (30, 30', 30") to the first configuration; detecting (305), with the sensor arrangement (50), a first pollutant level in a fluid flowing through the chamber (20) with the valve arrangement in the first configuration; switching (307) the valve arrangement to the second configuration;

detecting (309), with the sensor arrangement, a second pollutant level in a fluid flowing through the chamber with the valve arrangement in the second configuration; and determining (311) an efficiency of the air purification arrangement from the detected first pollutant level and the detected second pollutant level.

13. The method (300) of claim 12, wherein determining (311) an efficiency of the air purification arrangement from the detected first pollutant level and the detected second pollutant level comprises determining an actual clean air delivery rate of the air purifier (100).

14. The method (300) of claim 13, further comprising:

programming the processor (120) with a benchmark clean air delivery rate;

comparing (313) the actual clean air delivery rate of the air purifier (100) with the benchmark clean air delivery rate; and

generating (315) a warning signal if a deviation of the determined clean air delivery from the benchmark clean air delivery rate exceeds a defined threshold. 15. A computer program product comprising a computer readable storage medium having computer readable program instructions embodied therewith for, when executed on a processor (120) of an air purifier system (100) of any of claims 6-11 , cause the processor to implement the method (300) of any of claims 12-14.

Description:
AIR PURIFIER WITH POLLUTION SENSING

FIELD OF THE INVENTION

The present invention relates to a fluid sensor device for sensing a concentration (or concentration change) of an analyte of interest.

The present invention further relates to an air purifier system including such a fluid sensor.

The present invention yet further relates to a method of operating such an air purification arrangement.

The present invention still further relates to a computer program product for implementing such a method.

BACKGROUND OF THE INVENTION

Air purifiers typically comprise one or more pollutant removal structures, such as one or more filters, catalytic converters, electrostatic precipitators, and so on. The one or more filters may include air filters such as carbon filters, HEPA filters, odour filters, antibacterial filters or the like. Catalytic converters may be used to break down gaseous pollutants into smaller molecules, e.g. H 2 0 and C0 2 . Electrostatic precipitators may be employed for the removal of charged particles via collector plates. Other pollutant removal technologies employed in such a purifiers are also known.

Such pollutant removal structures have in common that they typically have a limited lifespan and must therefore be regularly replaced or serviced in order to ensure that the air purifier exhibits the desired performance characteristics, i.e. sufficiently purifies the air in a confined space in which the air purifier is placed, e.g. a room of a building such as an office space or a house.

A commonly used figure of merit for air purifiers is the clean air delivery rate (CADR), which expresses the fraction of pollutants that have been removed from the air times the CFM (cubic feet per minute) air flow rate through the air purifier.

However, it is not straightforward to predict when such pollutant removal structures need replacing or maintenance. Given that such pollutant removal structures, e.g. air filters, can be rather costly, it is desirable that such pollutant removal structures are not prematurely replaced or serviced as this can significantly increase the operating cost of an air purifier. On the other hand, if pollutant removal structure replacement or servicing is delayed beyond its end of life (EOL), the performance of the air purifier including the pollutant removal structure may become insufficient, which may lead to health problems for people occupying the confined space in which the air purifier is positioned. This is particularly prevalent for certain risk groups; it is well documented that pregnant women, infants/children, elderly and people with respiratory or cardiovascular disease are at increased risk from pollution exposure. For these groups, there is an enhanced need to minimize their exposure to air pollution.

Several air purifier manufacturers maintain fixed EOL values for the pollutant removal structures in the air purifier such that a user is prompted at regular intervals to replace or service such structures. However, this approximation does not factor in environmental conditions and operating times and may therefore lead to rather inaccurate approximations of the EOL of these pollutant removal structures.

According to GB/T 18801 standard, the lifetime of an air filter is reached once its initial CADR falls to 50%. The decrease in CADR, which for instance is caused by ageing of the air filter, correlates with an increase in the time required to reduce the room concentration of a pollutant. One of the attractions of such a standard is that it enables consumers to compare the standardized performance of different air purifiers such that an air purifier best matching a consumer's need can be more easily identified.

However, this standard is still based on generalized assumptions, e.g. 12 hours per day running time, fixed air exchange rates etc., without taking into account the actual usage of the air purifier. Since the actual life time depends on multiple factors related to the actual usage as introduced above, the problem arises that most of the users, when following the manufacturer's recommendations, will replace or service their pollutant removal structure either too early, which causes unnecessary costs or too late, which means that the pollutant removal structure is still used even when it is no longer able to reduce a pollutant level to a safe value.

CN 102019102 A discloses a method for real-time monitoring of the pollution level of a filter layer of an air purification machine, comprising a detection method of air quality. The method is characterized in that air quality sensors are arranged at the air inlet end and the air outlet end of the filter layer and used for detecting the air quality at the two sides of the filter layer; and an operation circuit judges the pollution level of the filter layer according to air quality signals detected by the two air quality sensors. When the filter layer is severely polluted so that the purification effect is poor, an alarm signal can be sent out to remind a user of timely changing or washing the filter layer, thereby ensuring the use effect of the air purification machine. The need to integrate multiple air quality sensors into the air purification machine increases its cost, which may be undesirable. Moreover, the use of multiple air quality sensors may complicate the accurate determination of the filter layer EOL, for example because the respective air quality sensors exhibit a different drift in sensitivity over time, e.g. because the air quality sensor in front of the filter layer becomes more contaminated with pollutants than the air quality sensor behind the filter layer.

SUMMARY OF THE INVENTION

The present invention seeks to provide a fluid sensor device that can determine the concentration of an analyte of interest in multiple fluid streams.

The present invention further seeks to provide an air purifier system including such a fluid sensor.

The present invention yet further seeks to provide a method of operating such an air purification arrangement.

The present invention still further seeks to provide a computer program product for implementing such a method.

According to an aspect, there is provided a fluid sensor device comprising a chamber having a first inlet, a second inlet and an outlet; a valve arrangement configured to fluidly connect the first inlet to the outlet in a first configuration; and fluidly connect the second inlet to the outlet in a second configuration; a controller adapted to switch the valve arrangement between the first configuration and the second configuration; and a sensor arrangement in the chamber arranged to detect a first pollutant level in a fluid flowing through the chamber in the first configuration and to detect a second pollutant level in a fluid flowing through the chamber in the second configuration. Such a fluid sensor device facilitates the measurement of pollutant levels in multiple fluid streams, i.e. a first fluid stream entering the device via the first inlet and a second fluid stream entering the device via the second inlet using a single sensor arrangement within the chamber, i.e. downstream from the respective fluid inlets, thereby reducing the overall cost for measuring pollutant levels in multiple fluid streams (as only a single sensor arrangement is required) as well as improving the accuracy of any trends detected when comparing the sensed pollutant levels in the first and second fluid streams respectively due to the fact that these pollutant levels have been determined by the same sensor arrangement, thus minimizing the risk of inaccuracies in such comparisons due to a sensor sensitivity mismatch in case of sensors dedicated to each fluid stream.

The valve arrangement is typically used to allow only one of the first and second inlets to be fluidly connected to the sensor arrangement. In an embodiment, the valve arrangement comprises a first valve, which has the advantage of providing a particularly simple arrangement. The first valve may be rotatably mounted in the chamber such that by rotation of the first valve the desired inlet of the fluid sensor device may be fluidly connected to the sensor arrangement in the chamber

Alternatively, the valve arrangement further comprises a second valve, wherein the first valve is configured to block the first inlet in the first configuration and to unblock the first inlet in the second configuration; and the second valve is configured to unblock the second inlet in the first configuration and to block the second inlet in the second configuration. This arrangement is for instance advantageous in case a design including a single valve only is cumbersome or expensive, in which case the pair of valves may be used to configurably connect the desired fluid stream to the sensor arrangement.

The sensor arrangement may be located in any suitable location in the chamber. In an embodiment, the sensor arrangement comprises a sensor in the outlet, which has the advantage that the sensor does not interfere with the operation of the valve arrangement.

According to another aspect, there is provided an air purifier system comprising an air purifier comprising an air purification path extending from an air purification inlet to an air purification outlet; an air purification arrangement in the air purification path between the air purification inlet and the air purification outlet; and the fluid sensor device of any of the embodiments described in this application, wherein the first inlet is an ambient air inlet and the second inlet is fluidly connected to a section of the air purification path in between the air purification arrangement and the air purification outlet; and a processor communicatively coupled to the sensor arrangement, the processor being arranged to determine an efficiency of the air purification arrangement from the first pollutant level and the second pollutant level detected with the sensor arrangement. Such an air purification system can accurately predict the EOL of the air purification arrangement or parts thereof, e.g. of one or more filters, catalytic converters, electrostatic precipitators, and so on by the inclusion of the fluid sensor device due to the fact that pollution levels in the fluid streams upstream as well as downstream from the air purification arrangement are monitored with the same sensor arrangement, thereby reducing overall cost of the air purifier system and/or improving EOL estimation accuracy for the air purification arrangement.

The first inlet may be fluidly connected to a section of the air purification path in between the air purification inlet and the air purification arrangement to obtain a particularly accurate reading of the pollutant levels entering the air purifier system, for example by avoiding the impact on pollutant levels by turbulence created by the air purifier system external to its inlet.

The processor may be integral to the air purifier or may be included in a processing device communicatively coupled to the air purifier. A processor integral to the air purifier facilitates the provision of the indication of the efficiency of the air purification arrangement, e.g. its expected EOL, on the air purifier, thereby providing a self-contained air purification system. For example, the air purifier system may comprise a sensory output device, wherein the processor is adapted to provide the sensory output device with a control signal for generating a sensory output indicative of the efficiency of the air purification arrangement.

Alternatively, the inclusion of the processor in a remote processing device such as a personal computer, tablet computer, a mobile communication device such as a smart phone or the like, facilitates the provision of the indication of the efficiency of the air purification arrangement in locations that are remote to the location of the air purifier such that a user of the air purifier may be alerted regarding the efficiency of the air purification arrangement in any location in which the air purifier can communicate with such a remote processing device, thereby minimizing the risk of a delay in a user noticing the need to service or replace the air purification arrangement, which delay may cause the air purification system to operate sub-standardly for a period of time, e.g. because the replacement or servicing of the air purification arrangement was not ordered in time to avoid the air purification arrangement operating beyond its EOL.

In an embodiment, the processor arranged to determine an efficiency of the air purification arrangement from the first pollutant level and the second pollutant level detected with the sensor arrangement is adapted to determine a clean air delivery rate (CADR) of the air purifier from the first pollutant level and the second pollutant level. The processor may be further adapted to compare the determined clean air delivery rate against a benchmark clean air delivery rate and to generate a warning signal if a deviation of the determined clean air delivery rate from the benchmark clean air delivery rate exceeds a defined threshold.

According to yet another aspect, there is provided a method of operating the air purifier system of any of the embodiments described in this application, the method comprising switching the valve arrangement to the first configuration; detecting, with the sensor arrangement, a first pollutant level in a fluid flowing through the chamber with the valve arrangement in the first configuration; switching the valve arrangement to the second configuration; detecting, with the sensor arrangement, a second pollutant level in a fluid flowing through the chamber with the valve arrangement in the second configuration; and determining an efficiency of the air purification arrangement from the detected first pollutant level and the detected second pollutant level.

Such a method facilitates the accurate determination of the efficiency of the air purification arrangement in a cost-effective manner due to the fact that both fluid streams are exposed to the same sensor arrangement.

Determining an efficiency of the air purification arrangement from the detected first pollutant level and the detected second pollutant level may comprises determining an actual clean air delivery rate of the air purifier in order to assess the efficiency of the air purification arrangement. The method may further comprise programming the processor with a benchmark clean air delivery rate; comparing the actual clean air delivery rate of the air purifier with the benchmark clean air delivery rate; and generating a warning signal if a deviation of the determined clean air delivery from the benchmark clean air delivery rate exceeds a defined threshold. Such a warning signal for example may be used to indicate the EOL or expected EOL of the air purification arrangement.

According to still another aspect, there is provided a computer program product comprising a computer readable storage medium having computer readable program instructions embodied therewith for, when executed on a processor of an air purifier system of any of the embodiments described in the present application, cause the processor to implement the method of any of the embodiments described in the present application. Such a computer program product for example may be installed on an existing apparatus, e.g. a personal computer, tablet computer, mobile communication device and so on, thereby facilitating the determination of the efficiency of the air purification arrangement on such an apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described in more detail and by way of non-limiting examples with reference to the accompanying drawings, wherein:

FIG. 1 schematically depicts a fluid sensor device according to an embodiment in a first configuration;

FIG. 2 schematically depicts a fluid sensor device according to an embodiment in a second configuration;

FIG. 3 schematically depicts a fluid sensor device according to another embodiment in a first configuration;

FIG. 4 schematically depicts a fluid sensor device according to another embodiment in a second configuration;

FIG. 5 schematically depicts an air purification arrangement according to an embodiment in a first configuration;

FIG. 6 schematically depicts an air purification arrangement according to an embodiment in a second configuration; FIG. 7 schematically depicts an air purification arrangement according to another embodiment; and

FIG. 8 is a flowchart of a method of operating an air purification arrangement according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

FIG. 1 schematically depicts a fluid sensor device 10. The fluid sensor device 10 comprises a chamber 20 having a first inlet 21 , a second inlet 23 and an outlet 25. The chamber 20 may be made of any suitable material, e.g. a metal, metal alloy, polymer, polymer blend or combinations thereof, and the first inlet 21 , the second inlet 23 and the outlet 25 may have any suitable shape and dimensions. Within the chamber 20 is located a valve arrangement that selects which of the first inlet 21 and the second inlet 23 is fluidly connected to the outlet 25. In FIG. 1 the valve arrangement comprises a rotary valve 30 that is rotatably mounted within the chamber 20 on an axle 31 central to the chamber 20. The rotary valve 30 and the axle 31 individually may be made of any suitable material, e.g. g. a metal, metal alloy, polymer, polymer blend or combinations thereof. In FIG. 1, the rotary valve 30 is positioned in a first configuration in which the first inlet 21 is fluidly connected to the outlet 25 whereas in FIG. 2 the rotary valve 30 is repositioned to a second configuration in which the second inlet 23 is fluidly connected to the outlet 25. The axle 31 may comprise or be coupled to an actuator for switching the rotary valve 30 between a first configuration and the second configuration.

The valve arrangement is controlled by a controller 40 adapted to switch the valve arrangement between the first configuration and the second configuration. The controller 40 may be any suitable controller, e.g. a microcontroller unit (MCU), a generic processor operable to control the valve arrangement, and so on. The controller 40 may be responsive to an external control signal as will be explained in further detail below. The fluid sensor device 10 further comprises a sensor arrangement 50 in the chamber arranged to detect a first pollutant level in a fluid flowing through the chamber in the first configuration and to detect a second pollutant level in a fluid flowing through the chamber in the second configuration. To this end, the sensor arrangement 50 is located within the chamber such that the sensor arrangement is exposed to a fluid stream from the first inlet 21 to the outlet 25 when the valve arrangement in the first configuration as well as to a fluid stream from the second inlet 23 to the outlet 25 when the valve arrangement is in the second configuration. For example, the sensor arrangement 50 may be located in or near the outlet 25.

The sensor arrangement 50 may comprise one or more sensors for sensing targeted pollutants in the respective fluid streams through the chamber 20 in the first and second configurations. The sensor arrangement 50 for example may comprise one or more of a particulate matter sensor such as a PM 2.5 sensor, a gas sensor, a pollen sensor, a microorganism sensor, a (bio)aerosol sensor and an odour sensor. Other suitable sensor types are well-known per se and may also be contemplated. The sensor arrangement 50 is typically arranged to provide a sensor output for each sensor within the sensor arrangement, which sensor output is indicative of a sensed concentration of the pollutant targeted by that sensor. The sensor outputs may be forwarded to a processor adapted to calculate a difference between a first sensor output obtained with the valve arrangement in the first configuration and a second sensor output obtain to with the valve arrangement in the second configuration. This difference for example may be used to determine the efficiency of an air purification arrangement in between a first location from which a fluid stream is received in the first configuration and a second location from which a fluid stream is received in the second configuration, as will be explained in further detail below.

Although in FIG. 1 and 2 the valve arrangement comprises a singular rotary valve 30, it should be understood that embodiments of the fluid sensor device 10 are not limited thereto. FIG. 3 and 4 schematically depict an alternative embodiment in which the valve arrangement comprises a first valve 30' under control of the controller 40 and arranged to open or close the first inlet 21, and further comprises a second valve 30" 30' under control of the controller 40 and arranged to open or close the second inlet 23. In this embodiment, the controller 40 is typically arranged to simultaneously control the first valve 30' and the second valve 30" such that the first inlet 21 is opened and the second inlet 23 is closed in the first configuration, which is shown in FIG. 3, and to simultaneously control the first valve 30' and the second valve 30" such that the first inlet 21 is closed and the second inlet 23 is opened in the second configuration, which is shown in FIG. 4. The first valve 30' and the second valve 30" may be made of any suitable material, e.g. a metal, metal alloy, polymer, polymer blend or any combination thereof. In this embodiment, the sensor arrangement 50 is shown to be located in the outlet 25 by way of non-limiting examples only; in this embodiment the sensor arrangement 50 may be located in any suitable location within the chamber 20 although a location in or near the outlet 25 may be preferable.

The fluid sensor device 10 may be used in any application in which a differential measurement of a pollutant is desirable, for example to determine the efficiency of a pollutant capturing structure. FIG. 5 schematically depicts an air purifier 100 having an air inlet 101, an air outlet 103 and an air purification path 105, e.g. a fluid conduit, extending between the air inlet 101 and the air outlet 103. An air purification arrangement 110 is located in the air purification path 105 to remove targeted pollutants from the ambient air entering the air purifier 100 through the air inlet 101 such that purified air is expelled from the air purifier 100 through the air outlet 103. Although not explicitly shown for the sake of clarity only, the air purification path 105 may further comprise a pump or similar fluid displacement means for sucking ambient air into the air purification path 105 through the air inlet 101 and expelling the purified air back into ambient through the air outlet 105. Any suitable type of air purifier 100, e.g. portable air purifiers, may be used.

The air purification arrangement 1 10 may comprise one or more suitable pollutant removal structures, e.g. filters such as HEPA filters, carbon filters, catalytic converters, electrostatic precipitators, and so on, in order to remove pollutants such as particulate matter, pollen, odours, bacteria, formaldehyde and so on from the atmosphere in a space in which such an air purifier 100 is placed.

The air purifier 100 further comprises the fluid sensor device 10 in which the first inlet 21 is fluidly connected to the ambient atmosphere of the air purifier 100 such that the first inlet 21 can receive an air sample upstream from the air purification arrangement 110 in the first configuration of the fluid sensor device 10, such that the sensor arrangement 50 (here shown in the outlet 25 by way of non-limiting example) can determine the levels (concentrations) on one or more target pollutants in the air prior to purification of the air with the air purification arrangement 110. The second inlet 23 of the fluid sensor device 10 is fluidly connected to a section 105' of the air purification path 105 downstream from the air purification arrangement 110 such that that the sensor arrangement 50 can determine the levels (concentrations) on one or more target pollutants in the air after purification of the air with the air purification arrangement 110 in the second configuration of the fluid sensor device 10, which is schematically depicted in FIG. 6.

In this manner, the efficiency of a particular pollutant removal structure of the air purification arrangement 110 may be determined from the difference between a first sensor reading of that particular pollutant in the first configuration of the fluid sensor device 10 and a second sensor reading of that particular pollutant in the second configuration of the fluid sensor device 10. The sensor arrangement 50 may be arranged to provide the respective sensor readings to a processor 120 of the air purifier 100, with the processor 120 being adapted to calculate the efficiency of the particular pollutant removal structure from the first sensor reading and the second sensor reading. Any suitable type of processor 120 may be used for this purpose, e.g. a general purpose processor configured with computer program code to perform the required calculation, a dedicated processor such as an ASIC or a microprocessor, and so on.

For example, the processor 120 may be adapted to determine the actual CADR of the particular pollutant removal structure from the following equation:

CADR = ^-^ * (1)

In Equation (1), CADR is the Clean Air Delivery Rate of the air purifier 100, Ci is the inlet air pollutant concentration of the air purifier 100 as determined with the fluid sensor device 10 in the first configuration, C 2 is the outlet air pollutant concentration of the air purifier 100 as determined with the fluid sensor device 10 in the second configuration and Φ is the air flow rate of the air purifier 100. The air flow rate of the may be obtained in any suitable manner, e.g. by including a flow meter (not shown) in the air purification path 105 or by providing a look-up table or the like accessible by the processor 120 from which the air flow rate may be obtained by identifying the appropriate air flow rate based on a user-specified flow rate setting of the air purifier 100, e.g. by selecting a flow rate on the user interface of the air purifier 100. Other suitable ways for the processor 120 to obtain the air flow rate Φ will be immediately apparent to the skilled person.

The processor 120 may be adapted to compare the actual CADR as determined with Equation (1) against a benchmark CADR for the particular pollutant removal structure. Such a benchmark CADR for instance may be CADR specified by the manufacturer of the particular pollutant removal structure, e.g. a rated CADR obtained in a lab test following strict test procedures and safety guidelines, which may be programmed into the processor 120 or into a memory accessible by the processor 120 or may be an initial CADR determined with the fluid sensor device 10, e.g. in a calibration mode after installation of the particular pollutant removal structure. Such a calibration mode may be initiated in any suitable manner, e.g. by a user or automatically following the detection of a replacement or servicing of the particular pollutant removal structure. This for instance may be detected by a sudden increase of the CADR as determined from first and second sensor readings performed with the fluid sensor device 10.

In an embodiment, the processor 120 may comprise or may have access to a data storage device (not shown) in which the processor 120 may store CADRs determined with the fluid sensor device 10 as explained above in order to build a history of CADRs. Such a history for example may be used to predict an EOL of the particular pollutant removal structure, e.g. by extrapolating when the CADR of the particular pollutant removal structure is expected to reach a critical value based on the time elapsed between the determination of the initial value of the CADR in the history and the actual value of the CADR of the particular pollutant removal structure.

The processor 120 may be adapted to generate a warning signal when the actual CADR approaches or reaches a critical value. For example, a particular pollutant removal structure may be considered to have reached its EOL if its actual CADR is 50% of its benchmark CADR. In other words, the processor 120 may be adapted to generate a warning signal if a deviation of the CADR of the particular pollutant removal structure from its benchmark CADR exceeds a defined threshold, e.g. is at least 50% less than the benchmark CADR. Other defined threshold values are of course equally feasible. The warning signal may be produced on a sensory output device 130 of the air purifier 100 to alert a user that the monitored particular pollutant removal structure needs servicing and replacing. In this manner, sub-standard air purification with the air purifier 100 due to the particular pollutant removal structure exhibiting sub-standard CADR characteristics can be reduced or avoided altogether.

In an embodiment, the processor 120 may generate a first warning signal indicative of the particular pollutant removal structure approaching a critical CADR and a second warning signal indicative of the particular pollutant removal structure reaching the critical CADR, i.e. an EOL-indicating CADR, such that the user may timely order a replacement particular pollutant removal structure (or a servicing of the monitored particular pollutant removal structure) in response to the first warning signal and may replace the old particular pollutant removal structure with the replacement particular pollutant removal structure (or have the monitored particular pollutant removal structure serviced) in response to the second warning signal.

The sensory output device 130 may be any device capable of producing an output that can be detected by one of the human senses. For example, the sensory output device 130 may be adapted to produce a visible or audible output in response to a warning signal generated with the processor 120. For example, the sensory output device 130 may comprise a display and/or one or more LEDs adapted to provide a visible output and/or may comprise a loudspeaker or the like to produce an audible output in response to such a warning signal. Other suitable embodiments of such a sensory output device 130 will be immediately apparent to the skilled person.

FIG. 7 schematically depicts an alternative embodiment of an air purifier system in which the air purifier 100 is adapted to communicate with a remote computing device 200. In this embodiment, the air purifier 100 comprises a wireless communication module 140 communicatively coupled between the sensor arrangement 50 and an aerial 141. The wireless communication module 140 is adapted to wirelessly communicate the respective sensor readings generated with the fluid sensor device 10 in the first and second configurations to the remote computing device 200. In this embodiment, the remote computing device 200 comprises the processor 120 and the sensory output device 130, with the processor 120 receiving the wirelessly communicated sensor readings from the sensor arrangement 50 through a further wireless communication module 210 of the remote computing device 200. The further wireless communication module 210 may be communicatively coupled to a further aerial 21 1 for receiving the wireless communications transmitted via the aerial 141 of the air purifier 100.

In this embodiment, a user of the air purifier 100 being in possession of the remote computing device 200 may monitor the CADR of the respective pollutant removal structures of the air purification arrangement 110 remotely, which has the advantage that the user can be remotely alerted of the impending EOL of such a pollutant removal structure, such that the user can take immediate action to avoid sub-standard performance of the air purifier 100 rather than having to be in the direct vicinity of the air purifier 100 in order to notice such an alert.

The remote computing device 200 may be a portable device such as a tablet computer, a mobile communications device such as a smart phone, a laptop computer or a stationary device such as a desktop computer. Other suitable embodiments of such a remote computing device 200 will be immediately apparent to the skilled person. The remote computing device 200 and the air purifier 100 may communicate with each other through their respective wireless modules 140, 210 using any suitable wireless communication protocol, e.g. Bluetooth, Wi-Fi, a mobile communication protocol such as 2G, 3G, 4G or 5G, a suitable near-field communication (NFC) protocol or a proprietary protocol. In case of such wireless communication, the respective devices may communicate directly with each other or may communicate with each other through an intermediary such as a wireless bridge, a router, a hub, and so on. Any suitable embodiment of wireless communication between such respective devices may be contemplated.

The processor 120 may be further communicatively coupled to a data storage device (not shown), which may form part of the computing device 200. Such a data storage device may be any suitable device for storing digital data, e.g. a random access memory, a cache memory, a Flash memory, a solid state storage device, a magnetic storage device such as hard disk, an optical storage device and so on. Alternatively, the data storage device may be separate from the computing device 200, e.g. a network storage device or a cloud storage device accessible to the processor 120 over a network such as a LAN or the Internet.

The processor 120 may be adapted to store historical CADRs in the data storage device 33 as previously explained. The data storage device may further comprise computer readable program instructions that, when executed by the processor 120, causes the processor 120 to calculate the actual CADR from the sensor readings received from the air purifier 102 calculate (estimate) the EOL of the monitored pollutant removal structure from the actual and a benchmark CADR as explained above.

In an embodiment, the processor 120 may exploit the EOL estimation to automatically place an order for a new pollutant removal structure, e.g. filter or the like, or to order the servicing of an existing pollutant removal structure, e.g. a catalytic converter or electrostatic precipitator, via the Internet once the processor 120 determines that the predicted EOL reaches a defined threshold, e.g 2 weeks. To this end, the remote computing device 200 or the air purifier 100 in case of the processor 120 forming part of the air purifier may be configured with details about the particular air purifier 100 and the relevant pollutant removal structure(s), such that the computing device 200 or the air purifier 100 can autonomously action servicing or replacement ordering of the relevant pollutant removal structure. For example, such details may be provided by a user during an initial system set-up, where a user registers these details via an app or the like. Alternatively, the remote computing device 200 and the air purifier 100 may be adapted to communicate with each other, e.g. over a wireless link, with the air purifier 100 providing the necessary details to the remote computing device 200 over the wireless link.

It should be understood that in some embodiments the processor 120 may form part of the fluid sensor device 10, thereby providing a fluid sensor device 10 that can autonomously determine a change in concentration of one or more pollutants between the respective fluid streams passed through the fluid sensor device 10 via the first and second inlets as explained above. FIG. 8 is a flowchart of an example embodiment of a method 300 of the present invention. The method 300 starts in 301 for example by switching on the air purifier 100 before proceeding to 303 in which the valve arrangement of the fluid sensor device 10 is switched to the first configuration in which the first inlet 21 is fluidly connected to the outlet 25 such that the sensor arrangement 50 is exposed to a fluid stream passing from the first inlet 21 to the outlet 25. The fluid sensor device 10 may autonomously switch to the first configuration, e.g. the controller 40 may operate autonomously, or may switch to the first configuration in response to a configuration request signal provided by the processor 120. Upon exposure of the sensor arrangement 50 to this fluid stream, the sensor arrangement detects in 305 a first pollutant level in this fluid stream. It should be understood that the first pollutant level of several pollutants may be simultaneously detected by the sensor arrangement 50 as previously explained.

Next, the valve arrangement of the fluid sensor device 10 is switched to the second configuration in 307 such that the second inlet 23 is fluidly connected to the outlet 25 and the sensor arrangement 50 is exposed to fluid stream passing from the second inlet 23 to the outlet 25. The fluid sensor device 10 may autonomously switch to the second configuration, e.g. the controller 40 may operate autonomously, or may switch to the second configuration in response to a configuration request signal provided by the processor 120. The fluid sensor device 10 may be arranged to switch to the second configuration after a certain time delay, e.g. a fraction of the second, a second or several seconds, and so on. This time delay is typically governed by the time it takes for the sensor arrangement 50 to accurately detect the first pollutant level in 305.

Upon exposure of the sensor arrangement 50 to the fluid stream of the second configuration, the sensor arrangement detects in 309 a second pollutant level in this fluid stream. It should be understood that the second pollutant level of several pollutants may be simultaneously detected by the sensor arrangement 50 as previously explained. The fluid stream comprising the second pollutant level may be captured downstream from the air purification arrangement 110 and thus provides an indication of the purification efficiency of this arrangement when compared to the first pollutant level of the fluid stream captured upstream from the air purification arrangement 110. In 311, an efficiency of the air purification arrangement 110 is determined from the detected first pollutant level and the detected second pollutant level. This for instance may be achieved by calculation of the actual CADR of the monitored pollutant removal structure and comparing its actual CADR against a benchmark CADR for this structure as explained in more detail above. For example, the processor 120 may be programmed with the benchmark CADR or may obtain the benchmark CADR from an initial CADR determination with the sensor arrangement 50 as explained above.

Next, it is determined in 313 if the monitored pollutant removal structure has reached or is approaching its EOL as previously explained. If this is the case, a warning signal may be generated in 317 to alert a user that the monitored pollutant removal structure has reached or is approaching its EOL before the method 300 terminates in 319. If on the other hand it is determined in 313 that the monitored pollutant removal structure has not yet reached or approached its EOL, i.e. is functioning satisfactorily, e.g. has an actual CADR well above 50% of its benchmark CADR, it may be checked in 315 if the method 300 is to continue. If this is the case, the method 300 may revert back to 303, otherwise, the method may terminate in 319.

A computer program product may be provided that comprises a computer readable storage medium having computer readable program instructions embodied therewith. The computer readable program instructions, when executed on the controller 40 and/or processor 120 of any embodiment of the air purifier monitoring system may cause the controller 40 and/or processor 120 to implement any embodiment of the above described method 300. Such computer readable program instructions for instance may come in the form of a software program such as an app, which may be downloadable from a computer readable storage medium accessible over a network such as the Internet, which software program may be installed on the air purifier monitoring system, e.g. stored in a data storage device.

Aspects of the present invention may be embodied as a fluid sensor device 10, an air purifier system including an air purifier 100 incorporating such a fluid sensor device 10 and a method 300 for monitoring the performance of an air purification arrangement 110 of an air purifier 100 with the air purifier monitoring system. Aspects of the present invention may take the form of a computer program product embodied in one or more computer-readable medium(s) having computer readable program code embodied thereon. The code typically embodies computer-readable program instructions for, when executed on a controller 40 and/or processor 120 of such an air purifier monitoring system, implementing at least parts of the monitoring method 100.

Any combination of one or more computer readable medium(s) may be utilized.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Such a system, apparatus or device may be accessible over any suitable network connection; for instance, the system, apparatus or device may be accessible over a network for retrieval of the computer readable program code over the network. Such a network may for instance be the Internet, a mobile communications network or the like. More specific examples (a non-exhaustive list) of the computer readable storage medium may include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of the present application, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out the methods of the present invention by execution on the controller 40 and/or processor 120 may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the controller 40 and/or processor 120 as a stand-alone software package, e.g. an app, or may be executed partly on the controller 40 and/or processor 120 and partly on a remote server. In the latter scenario, the remote server may be connected to the air purification system through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer, e.g. through the Internet using an Internet Service Provider.

Aspects of the present invention are described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions to be executed in whole or in part on the controller 40 and/or processor 20 of the air purifier system, such that the instructions create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable medium that can direct the air purifier system to function in a particular manner.

The computer program instructions may be loaded onto the controller 40 and/or processor 120 to cause a series of operational steps to be performed on the controller 40 and/or processor 120, to produce a computer-implemented process such that the instructions which execute on the controller 40 and/or processor 120 provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. The computer program product may form part of the air purifier system, e.g. may be installed on the air purifier system.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.