Method for determining initial filter load value of air moving device

Abstract

A method (300) for determining an initial filter load value of an air moving device (200) includes applying a predetermined inlet limit value to the device. The method further includes operating the device while the device is arranged to have the predetermined entry limit value, and during operation, performing a measurement process to determine a first value of an operating parameter of the device. The first value of the operating parameter depends on a degree of filter loading of the installed filter. The method further includes performing a determination process to determine an initial filter load value based on a first predetermined relationship between the operating parameter value and the set of filter load values.

Description

Technical Field

[0001] The present invention relates to determining an initial filter load value of an air moving device, and in particular but not exclusively, to a set of machine-readable instructions, and to an air moving device having a memory including the instructions and a processor configured to determine the initial filter load value of the air moving device by executing the instructions. Further, the present invention relates to a system including one or more processors and a memory, the memory including a set of machine-readable instructions for determining an initial filter load value of an air moving device. Background Art

[0002] There is a general desire to improve air moving devices, such as vacuum cleaners, in a variety of ways. For example, improvements may be desired in terms of efficiency, manufacturing cost, usage flexibility, and reliability. Summary of the Invention

[0003] According to a first aspect of the present invention, there is provided a method for determining an initial filter load value of an air moving device, the method comprising: arranging the device in a calibration mode, the calibration mode setting a predetermined inlet restriction value for the device; operating the device in the calibration mode; during operation, performing a measurement process to determine a first value of an operating parameter of the device, the first value of the operating parameter depending on the filter load level of the installed filter; and performing a determination process to determine the initial filter load value based on a first predetermined relationship between the value of the operating parameter and a set of filter load values.

[0004] The method may allow for a reliable and accurate determination of the initial filter load value of the air moving device. The method may allow for calibration of the measurement of the filter load value after an event in which the load level of the filter of the device may have changed while the device is not operating. For example, the method may allow for determination of the initial filter load value after cleaning the filter of the device. In some embodiments, by arranging the device in a calibration mode, the calibration mode setting a predetermined inlet restriction value on the air moving device, the first predetermined relationship may be used to more reliably correlate the value of the operating parameter of the device with the initial filter load value.

[0005] The method may allow for determination of the filter load value based on observable parameters of the device related to the filter load value. In some examples, the method may also allow for obtaining the filter load value based on a measurement of the operating parameter, without the need, for example, to introduce the ability to directly measure the pressure on the filter to determine the level of the filter load. In some examples, this may allow for fewer sensors on the device, which helps to minimize product size, complexity, and cost.

[0006] In some examples, the method can allow for the flexible determination of a filter load value by using an operating parameter, which is obtained for other purposes during device operation and can be reused to determine the filter load value. Since the first predetermined relationship takes into account the inlet restriction in the relationship between the operating parameter value and the filter load value, the first predetermined relationship can allow for an accurate and reliable way to convert the operating parameter value into the filter load value under various different inlet restriction conditions.

[0007] In a calibration mode, a predetermined inlet restriction value can be set by either having no tool attached to the device or by attaching a predetermined tool to the device.

[0008] For example, by attaching a given tool to the device or removing all tools from the device, the device can be arranged with a predetermined inlet restriction value. Removing all tools from the device or attaching a given tool to the device can provide a simple and easily repeatable way to provide a predetermined inlet restriction for the device.

[0009] The method can include, in a calibration mode, prompting the user to arrange the device with a predetermined inlet restriction value or instructing the device to be arranged with a predetermined inlet restriction value.

[0010] The prompting can include prompting the user to remove all tools from the device or indicating that no tool is attached to the device.

[0011] For example, the user can be prompted to arrange the device with a predetermined inlet restriction value through the user interface of the air moving device. Alternatively, the prompting can be provided by another device that can communicate with the air moving device, such as a smartphone running an operating application.

[0012] The method can include, in a calibration mode, receiving an indication that the device is arranged with a predetermined inlet restriction value.

[0013] The indication can allow the air moving device to determine that the device is arranged with a predetermined inlet restriction value and, thus, is arranged for performing the step of determining an initial filter load value.

[0014] Receiving the indication can include detecting that the device is arranged with a predetermined inlet restriction value.

[0015] For example, the device can be configured to detect whether a tool is attached to the device and / or a given type of tool attached to the device. This can allow the device to detect whether the device is arranged to operate with a predetermined inlet restriction value or, for example, to detect a given predetermined inlet restriction value for determining an initial filter load value.

[0016] Receiving the indication can include receiving an indication from the user.

[0017] Receiving an indication from a user can allow the device to determine that the device is arranged to operate at a predetermined inlet restriction value without, for example, detecting whether a given tool is attached to the device or whether no tool is attached to the device.

[0018] The operating parameter can be: the operating pressure of the motor of the air moving device; or the speed of the motor of the air moving device.

[0019] Determining the filter load value based on the operating pressure of the motor or the speed of the motor can allow the filter load to be reliably and accurately determined based on observable physical parameters that are related to the filter load value in a predetermined manner. Both the operating pressure of the motor and the speed of the motor can be parameters that can be reliably measured and can be determined for other purposes, such as for monitoring the power output of the device. Thus, using these parameters to determine the filter load value can avoid the need for additional sensors or processing to perform this task.

[0020] The operating parameter can be the operating pressure of the motor of the air moving device, and the first value of the operating parameter can be the first value of the operating pressure of the motor, and the measuring process can include determining the first value of the operating pressure of the motor based on: an ambient pressure measurement; and a motor inlet pressure measurement during motor operation.

[0021] During motor operation, determining the first operating pressure value based on the ambient pressure measurement and the motor inlet pressure measurement can define the first operating pressure value as an operating pressure difference that is related to the filter load level in a reliable and precise manner under given inlet restriction conditions. It can also allow measurements made for other purposes related to the operation of the air moving device, such as ambient pressure, to be used to obtain the first value of the operating pressure of the motor.

[0022] The ambient pressure measurement and the motor inlet pressure measurement can be measured by a single pressure sensor at different times.

[0023] Measuring the ambient pressure measurement and the motor inlet pressure measurement by a single pressure sensor at different times can allow the first value of the operating pressure to be obtained by using a single pressure sensor. This can allow the operating pressure to be measured in a cost - and space - saving manner.

[0024] The operating parameter can be the operating pressure of the motor of the air moving device, and the first value of the operating parameter can be the first value of the operating pressure of the motor, and the measuring process can include determining the first value of the operating pressure of the motor based on: a first pressure measurement of the pressure upstream of the motor; and a second pressure measurement of the pressure downstream of the motor.

[0025] Using the pressure measurement upstream of the motor and the pressure measurement downstream of the motor can allow an accurate and reliable measurement of the operating pressure to be obtained in a simple manner.

[0026] The determining process may include: selecting a first predetermined relationship based on a predetermined inlet restriction value.

[0027] This may allow for the selection of a suitable predetermined relationship between the operating parameter value and the filter load value. For example, for different predetermined inlet restriction values, different relationships between the operating parameter value and the filter load value may be predetermined.

[0028] The determining process may include determining a first normalized value of the operating parameter by normalizing a first value of the operating parameter using one or more values of one or more respective normalization parameters, and in this determining process: the first predetermined relationship may be between the normalized value of the operating parameter and the filter load value; and determining an initial filter load value may be based on the first normalized value of the operating parameter.

[0029] Normalizing the value of the operating parameter using one or more normalization parameters may provide an effective way to obtain values that robustly and accurately map to the filter load value.

[0030] One or more normalization parameters may include one or more of the following: ambient pressure; ambient temperature; motor input power; and manufacturing tolerances of the air moving device.

[0031] These parameters may be easily determined, for example by using sensors, or may be predetermined, for example by a calibration procedure. Normalizing the value of the operating parameter using these parameters may provide a first value of the operating parameter to effectively map to the filter load value.

[0032] The method may be performed in response to replacement of a filter of the air moving device.

[0033] Replacement of the filter of the air moving device may be replacement of the filter after a filter cleaning event.

[0034] When the device is not operating, the state of one or more filters of the device may change. For example, the filter may be removed from the device and cleaned to remove dirt and / or dust.

[0035] The filter cleaning event may be performed in response to the device issuing a filter cleaning alert to the user.

[0036] When a given amount of dirt or dust has accumulated on the filter, a filter cleaning event can be performed. For example, when the filter load level reaches a given value, the user can be prompted to clean the filter. The method can be performed, for example, in response to the user replacing the filter in the device after removing the filter for cleaning in accordance with such a prompt. For example, the device can be configured to detect when the filter is removed and / or replaced, for example, by using a suitable sensor, such as a magnetic sensor. In one example, the device can be configured to cause the method to be performed, for example, at device startup, as long as a filter cleaning prompt has been provided. Thus, even if the removal and / or replacement of the filter is not detected, for example, because the device is turned off when this occurs, the device can still appropriately trigger the calibration process to be performed.

[0037] The method can provide an initial filter load value as a baseline value after such a filter cleaning event. This can provide a reliable initial baseline value for the filter load value, on the basis of which changes in the filter load level during device operation can be determined.

[0038] According to a second aspect of the present invention, a set of machine-readable instructions is provided which, when executed by one or more processors, causes the method according to the first aspect of the present invention to be performed. The method can be, for example, a computer-implemented method implemented by one or more processors of an air moving device or by one or more processors of a system comprising an air moving device and a control device, the control device being, for example, a smartphone configured to communicate with the air moving device and control aspects of the operation of the air moving device.

[0039] According to a third aspect of the present invention, an air moving device is provided, comprising: a processor; and a memory comprising a set of machine-readable instructions which, when executed by the processor, causes the processor to perform the method according to the first aspect of the present invention.

[0040] The air moving device can be a vacuum cleaner.

[0041] According to a fourth aspect of the present invention, a system is provided comprising one or more processors and a memory, the memory comprising a set of machine-readable instructions which, when executed by at least one of the one or more processors, causes at least one of the one or more processors to perform the method according to the first aspect of the present invention.

[0042] Where appropriate, optional features of aspects of the present invention can be equivalently applied to other aspects of the present invention. Description of the Drawings

[0043] The present invention will now be described, by way of example only, with reference to the following drawings, in which:

[0044] Figure 1Schematic diagram of an example motor assembly of an air moving device;

[0045] Figure 2 Schematic diagram of an example of an air moving device;

[0046] Figure 3 Flowchart representing a method for determining an initial filter loading value of an air moving device;

[0047] Figure 4 Graph showing the operating pressure value versus the inlet restriction value;

[0048] Figure 5 Graph further exemplifying the graph showing the operating pressure value versus the inlet restriction value;

[0049] Figure 6 Graph exemplifying the graph showing the filter loading value versus the operating pressure value; and

[0050] Figure 7 Block diagram of a system for implementing an example method for determining an initial filter loading value. Detailed Description

[0051] Figure 1 Shows an example schematic diagram of a motor assembly 100 of an air moving device. The motor assembly 100 includes a set of coils 102, a shaft 104 on which a magnet (not shown) is mounted, bearings 106, and an impeller 108. The motor assembly 100 includes a motor air inlet 110 and an air outlet / diffuser 112. The motor assembly includes a circuit board 114 on which sensors are mounted, including an ambient temperature sensor 116 and a first pressure sensor 118. The motor assembly 100 includes a housing 124 in which other components are accommodated. The motor assembly 100 also includes a motor pre-filter 126 for filtering the air drawn into the motor during use.

[0052] Figure 2Shows an example air moving device 200 including a motor assembly 100. The example air moving device 200 is a vacuum cleaner. The vacuum cleaner 200 includes an inlet tube 202, and a tool 204 is attached to the distal end of the inlet tube 202. The tool 204 is for engaging a surface to be cleaned by the vacuum cleaner and includes an air inlet (not shown) leading to the vacuum cleaner 200. The tool 204 can be active and include one or more mechanically operated components, such as a rotating brush bar, to assist in the cleaning task. Alternatively, the tool 204 can be passive and not include any such mechanically operated components. However, a passive tool can include elements such as bristles to assist in the cleaning task. In an example, the inlet tube 202 or a portion thereof can be removable. When the inlet tube 202 or a portion thereof is removed, a tool such as a passive tool can be attached to the device 200. The vacuum cleaner 200 also includes a dust separation chamber 206, which can be, for example, a cyclone chamber. The vacuum cleaner 200 also includes a processor 208 and a memory 210, and the memory 210 is for storing machine-readable instructions executed by the processor 208 to control the operation of the components of the vacuum cleaner 200 including the motor 100. In an example, the machine-readable instructions, when executed, can cause the processor 208 to perform any of the example methods described herein or aspects of these methods.

[0053] In use, the motor of the motor assembly 100 draws air through an air inlet into the air moving device 200, through the air moving device 200, and discharges it from an air outlet. The air is suctioned through the device 200 along an air flow path 128, and the air flow path 128 passes through the inlet tube 202, the dust separation chamber 206, the motor assembly 100, and exits the device 200 through the air outlet 212.

[0054] Back Figure 1 , when the motor is used for the air moving device 200, an electric current passes through the coil 102, thereby generating a changing magnetic field. This changing magnetic field acts on the magnet 106 on the shaft 104, causing the shaft 104 to rotate about its longitudinal axis. This in turn causes the impeller 108 to rotate. The air driven by the impeller 108 is drawn into the air moving device 200 along the air flow path 128. The air flow path 128 enters the motor assembly 100, passes through a pre-motor filter 126 that removes particulate matter from the air, and enters the housing 124 through an air inlet 110 (shown as a gap in the housing 124 in Figure 1 . The air flow path 128 continues through the motor to the impeller 108, and after passing through the impeller 108, exits the motor assembly 100 through the air outlet 112.

[0055] Figure 3 Shows a flow chart representation of an example method 300 for determining an initial filter load value of the air moving device 200.

[0056] The filter load value can be the load value of a filter that filters particulate matter from the airflow as the airflow passes through the motor. For example, the filter load can be the load level of the pre-motor filter 126. Alternatively, the filter load can be the load level of a post-motor filter (not shown). In some examples, the filter load value can take into account the load levels of multiple filters, such as the pre-motor filter and the post-motor filter. The load level of the filter can indicate the amount of dirt or dust collected in the filter, and / or a measure of the initial effectiveness after the filter has been cleaned (e.g., the filter may have been cleaned, but may not be "new" due to remnants of dirt or dust that may remain after cleaning). The load level of the filter can have an impact on the airflow through the device 200. For example, as the filter collects more dirt, the airflow through the device may become more restricted.

[0057] In an example, the filter load value can be expressed as a percentage. For example, a filter load value of 100% can represent the load level of the filter, which indicates that the filter should be cleaned or replaced. For example, a filter load value of 100% can correspond to a state where the amount of airflow restricted by one or more filters reduces the operating efficiency of the device by a given degree. For example, a filter load value of 100% can correspond to a state where one or more filters are not completely blocked, but are blocked to an extent sufficient to require cleaning or replacement of the filter. A filter load value of 0% can indicate that the filter has a minimum load level. For example, a filter load value of 0% can correspond to a state where one or more filters provide a minimum degree of restriction to the airflow through the device. For example, a filter load value of 0% can correspond to the filter load level provided by a new filter that has not collected dust or a filter that has been completely cleaned and is "as good as new". The actual degree of blockage or dust collection by one or more filters corresponding to a given filter load value can vary, e.g., depending on what degree of blockage is considered an acceptable level for the device to operate with sufficient efficiency. Typically, during the use of the device 200, as air passes through the device and dust is filtered from the air and collected by the filter, the filter load level gradually increases. When the filter is considered in need of replacement or cleaning, it can be removed from the device. Then the filter in the device can be cleaned and replaced. Alternatively, a new filter can replace the previous filter.

[0058] For example, the initial filter load value can be a value measured after an event that may have caused a change in the filter load level, e.g., when the device 200 is not operating. For example, the initial filter load value can be the filter load value after replacing one or more filters in the device 200, e.g., after cleaning the filter or replacing the filter with a new filter. The purpose of cleaning the filter is to reduce the filter load level. However, the filter load value after a filter cleaning event may be unknown. For example, as previously described, cleaning the filter may not always reduce the filter load value to zero. The method can allow measurement of the filter load value after such a cleaning event.

[0059] Method 300 includes, at block 302, arranging the device in a calibration mode that sets a predetermined inlet restriction value for the device. Method 300 also includes, at block 304, operating the device in the calibration mode.

[0060] The inlet restriction value of the air moving device 200 defines the level of restriction acting on the air inlet through which air flows into the device 200. The level of inlet restriction can typically vary based on various factors, such as obstacles that impede air flow into the device 200. The inlet restriction value can vary depending on the type of tool attached to the vacuum cleaner 200. For example, different tools can have different geometries that restrict the air flow into the vacuum cleaner 200 by different amounts. For example, different tools can have different air inlet diameters. Additionally, some tools can include elements that impede air flow into the device 200, such as bristles for cleaning carpets, while other tools may not include such elements. Further, the degree of inlet restriction can vary depending on the type of surface on which the vacuum cleaner 200 is used for cleaning. For example, a carpeted surface or a similar surface may impose a greater restriction on the air flow into the vacuum cleaner 200 than a smooth surface such as a wood or tile surface. Typically, operating the tool in free air, i.e., with the device not engaged with a surface such that there is no external impediment to air flow into the device 200, will provide the lowest inlet restriction value when the device is operated with a given tool attached or without a tool attached.

[0061] The inlet restriction value of the operating device can be defined in terms of the diameter of an orifice that will provide an equivalent level of restriction to the air flow into the device 200 under test conditions. For example, when used to clean a carpet surface, the vacuum cleaner 200 may operate at a high level of inlet restriction, which may be equivalent to operating under known conditions where an orifice plate has an orifice with a small diameter that restricts the air flow into the vacuum cleaner 200. Conversely, when cleaning a wood surface, the vacuum cleaner 200 can operate at a lower level of inlet restriction, equivalent to the inlet restriction presented by an orifice with a larger diameter.

[0062] The calibration mode sets a predetermined inlet limit value for device 200. For example, in the calibration mode, device 200 can be arranged to operate in a predetermined inlet limit state, in which no tool is attached to device 200 or a specific tool is attached to device 200. In one example, the predetermined inlet limit state includes device 200 operating in free air with no tool attached. In another example, the predetermined inlet limit state can include device 200 operating in free air with a specific tool attached. Removing all tools from the device or attaching a specific tool to the device can provide a simple and easily repeatable way to provide a predetermined inlet limit for the device.

[0063] Method 300 can include, in the calibration mode, prompting the user to arrange device 200 with a predetermined inlet limit value so that calibration can be performed.

[0064] For example, when providing the predetermined inlet limit value by removing all tools from the device, the user can be prompted to remove all tools from the device or, in the case where no tool is attached to the device, it can be indicated that no tool is attached to the device. For example, once the user has removed all tools from device 200, the user can be asked to indicate when no tool is attached to the device. Alternatively, in the case where the predetermined inlet limit is provided by a specific tool attached to the device, the user can be prompted to attach the specific tool to the device and, for example, indicate when they have attached it. The prompting and / or receipt of the indication can be performed by the device itself, such as by the user interface of the device, or can be performed by a different device, such as a smartphone communicating with the device operating the application.

[0065] In some examples, device 200 can be configured to detect whether a tool is attached to the device and / or what type of tool is attached to the device. In such examples, in the calibration mode, the device can determine the predetermined inlet limit value based on the detected tool or lack of tool. For example, one or more inlet limit values of the device can be predetermined, each predetermined inlet limit value corresponding to the situation when the device operates with a given corresponding tool attached. Device 200 can detect whether a tool is attached to the device and, if so, which tool is attached to the device. Using this information, the device can determine the predetermined inlet limit value to use in the method of determining the initial filter load value. In another example, regardless of whether the device is configured to detect which tool is attached to the device, the user can be requested to indicate which tool is attached to the device, and then the device can use this information to determine the predetermined inlet limit value to use during the calibration process.

[0066] In another example, the device can be configured to operate in a calibration mode with a given predetermined inlet restriction value. The device can then be configured to detect whether the correct tool (possibly no tool) is attached or the user indicates that the correct tool is attached to allow calibration to be performed.

[0067] Device 200 can be configured to run method 300 after an event in which the filter load value may have changed when the device is not operating. For example, device 200 can be configured to determine when to replace the filter, e.g., after cleaning the filter or replacing the old filter with a new filter, and in response, trigger the calibration mode. This can allow determination of the exact initial filter load value. The initial filter load value can then be used as a baseline for determining changes in the filter load value and other operating parameters of device 200.

[0068] As described above, at block 304, the method includes operating the device in a calibration mode. In some examples, the user can be prompted to operate the device. For example, once the device has received an indication that the device is arranged with a predetermined inlet restriction value, the user can be prompted to operate the device. As described above, the indication can be provided, for example, by the user providing an input that confirms that the correct tool (possibly no tool) is attached to the device, or by the device detecting which tool is attached to the device. In some examples, the device can be configured to automatically operate once it has received an indication that the device is arranged with a predetermined inlet restriction value. For example, in an example where the device is configured to detect which tool is attached, when the calibration mode is initiated, if the device detects that the correct tool is attached, the device can automatically operate as part of the calibration sequence.

[0069] Method 300 includes, at block 306, during operation, performing a measurement process to determine a first value of an operating parameter of the device, the first value of the operating parameter depending on the degree of filter loading of the installed filter.

[0070] The operating parameter can be the operating pressure of the motor of the air moving device 200. The operating pressure of the motor is the air pressure associated with the motor when the motor is operating, i.e., when the motor is running. The operating pressure can be related to the air pressure at one or more locations along the air flow path 128. The operating pressure can be an air pressure difference. The operating pressure can be, for example, the pressure difference between upstream and downstream positions in the motor assembly along the air flow path 128.

[0071] In another example, the operating pressure is the difference between a first pressure measured when the motor is not running and a second pressure measured when the motor is running. The first pressure and the second pressure can be measured at the same location. The value of the operating pressure can be obtained, for example, by determining the difference between a measurement of the ambient pressure and a pressure measurement during motor operation, where the ambient pressure measurement is obtained when the motor is not running (e.g., before starting the air moving device 200). In some examples described herein, such an operating pressure is referred to as δ-p. The pressure measurement taken during motor operation can be made, for example, at the air inlet 110. Alternatively, the measurement can be made at the air outlet of the motor. In some examples, the pressure measurements used to obtain the value of the operating pressure can be made by the same pressure sensor. This allows for the use of a single pressure sensor to obtain the value of the operating pressure, which can save cost and space.

[0072] In another example, the operating pressure used in the example method can be determined based on the pressure difference between two locations (e.g., an upstream location and a downstream location) in the motor assembly 100. For example, an additional pressure sensor (not shown) can be configured to make a pressure measurement at a location downstream of the first pressure sensor 118 along the air flow path 128. The additional pressure sensor can be configured to measure the pressure at the air inlet 109 of the impeller 108. Then, the difference between the pressure measured by the first pressure sensor 118 and the pressure measured by the additional pressure sensor, or a dynamic pressure value derived from these two pressures, for example, can be used as an operating parameter.

[0073] In other examples, the operating parameter can be a parameter other than the operating pressure, such as the speed of the motor of the air moving device 200. The speed can be measured, for example, by a suitable sensor (not shown in the figures). In other examples, the operating parameter can be the air flow rate through the device 200. Examples of determining the air flow rate will be described below.

[0074] The value of the operating parameter depends on the degree of filter loading of the installed filter. For example, as described above, the filter loading level can affect the air flow through the device, which in turn can affect the value of the operating parameter, such as the operating pressure of the device or the speed of the motor of the device.

[0075] The device can be configured to operate for a predetermined time to allow for a reliable measurement of the value of the operating parameter. For example, the device can be configured to operate for a period of time after startup to allow the operating parameter to stabilize. In one example, the device is configured to operate for 3 seconds to allow for the measurement of the operating parameter. In some examples, the measurement of the operating parameter can be obtained by averaging multiple measurements. For example, the device can measure the operating pressure once per second, and the value of the operating pressure used to determine the initial filter load value can be the average of two or more such measurements.

[0076] Method 300 further includes, at block 308, performing a determination process to determine an initial filter load value based on a first predetermined relationship between an operating parameter value and a set of filter load values.

[0077] The first predetermined relationship can include, for example, a curve or a look-up table that associates the operating parameter value with the set of filter load values. The first predetermined relationship allows the determination of the filter load value based on the measurement of the operating parameter.

[0078] The relationship between the operating parameter value and the filter load value can be obtained, for example, by measuring these values under predetermined test conditions. This can include, for example, operating device 200 with a controlled, predefined inlet restriction value, such as using an orifice plate with a given diameter orifice, and measuring the operating parameter value and the filter load value. The inlet restriction value can be set by operating device 200 with an orifice plate having orifices of different diameters to restrict the airflow into device 200. Measurements can be made for different inlet restriction values to establish the relationship between the operating parameter values and the filter load values for different inlet restriction values. In an example, this process can be done as part of the manufacturing or initial setup process of device 200.

[0079] In an example, depending on the inlet restriction value, a given value of the operating parameter can correspond to different filter load values. Thus, if the inlet restriction value is unknown, it may be difficult to unambiguously determine the filter load value based on the measurement of the operating parameter. However, by arranging the device with a predetermined inlet restriction value, the operating parameter value can be determined based on the relationship between the operating parameter value and the filter load value that is applicable when the device is operated at the predetermined inlet restriction value.

[0080] Once the initial filter load value is determined, the initial filter load value can provide a baseline value that the device can use to determine the change in the filter load value over time during device operation.

[0081] In some examples, one or more additional parameters of the device can also be used to associate the value of the operating parameter with the filter load value at a given inlet restriction value. The filter load value can then be determined based on the first value of the operating parameter, the predetermined inlet restriction value, and the corresponding values of the one or more additional parameters. The other parameters can be parameters of the air moving device 200 that affect the value of the operating parameter that is measured for a given value of the inlet restriction. For example, in some embodiments, for the same inlet restriction value and the same filter load value, different parameter values, such as ambient pressure, ambient temperature, motor input power, and manufacturing tolerances of the air moving device, may result in different operating parameter values.

[0082] Ambient pressure and ambient temperature form part of the external conditions for the operation of device 200. In some examples, the ambient pressure can be measured by the first pressure sensor 118 before the motor is started. The ambient temperature can be measured by the temperature sensor 116. Motor input power is the power used to drive the motor.

[0083] The motor input power can be controlled by the processor 208 and, for example, DC or AC power can be supplied from a battery (not shown) of the device 200 or from a mains power supply. The motor input power can control the suction power of the air moving device.

[0084] Manufacturing tolerances of the air moving device 200 can account for variability in operation between different devices. For example, during a calibration process after device assembly, various operating parameters of the device can be measured. The manufacturing tolerance of a particular device can be expressed as a percentage of the total allowable tolerance. In one example, at the end of the device production line, an orifice plate with a given diameter orifice is connected to the inlet of the device, where the device is known to have a clean filter, i.e., a filter load value of 0%. The ambient temperature and pressure are measured. The device is operated at a given power level and the operating parameters, such as δ-P, are measured. With the input power, ambient temperature, ambient pressure, and filter load value measured or otherwise known, the measured δ-P represents the manufacturing tolerance factor. This process can be repeated at multiple power levels and different orifice diameters.

[0085] In some examples, a normalized value of the operating pressure is obtained by normalizing the value of the operating parameter with respect to one or more other parameters (such as those mentioned above). For example, a five-dimensional look-up table can be defined that maps the corresponding values of manufacturing tolerance, ambient pressure, ambient temperature, motor input power, and operating pressure value to the normalized value of the operating pressure. A predetermined relationship between the normalized value of the operating pressure and the filter load value at a predetermined inlet limit value can be used to determine the initial filter load value.

[0086] Figure 4 An example of a relationship curve between the normalized value of the operating pressure and the inlet limit value is shown. This example is for the motor of a vacuum cleaner.

[0087] In Figure 4In the example, the operating parameter shown on the y-axis is the normalized operating pressure, i.e., the normalized δ-P value, which defines the difference between the motor ambient pressure before startup and the pressure at the motor inlet during operation. The unit of δ-P is kilopascal. The orifice diameter in millimeters is along the x-axis and represents the inlet restriction value. The first curve 402 maps the normalized δ-P value to the inlet restriction value, and this curve is obtained through a suitable calibration process that involves operating the vacuum cleaner under known conditions, with the inlet restriction provided by orifices of different diameters. The corresponding values of the orifice diameter and δ-P have been measured. The first curve 402 is obtained by normalizing the value of δ-P with respect to the values of manufacturing tolerances, ambient pressure, ambient temperature, and motor input power. The first curve 402 maps the normalized value of the operating pressure to the inlet restriction value of a single filter load value.

[0088] Figure 5 A set of curves 402, 504, 506, 508, 510 is shown, which relate the normalized value of δ-P to the inlet restriction value. Each curve corresponds to a different filter load value. Figure 4 The first curve 402 of is also shown in Figure 5 and corresponds to a filter load value of 0%. The second curve 504 corresponds to a filter load value of 25%. The third curve 506 corresponds to a filter load value of 50%. The fourth curve 508 corresponds to a filter load value of 75%. The fifth curve 510 corresponds to a filter load value of 100%.

[0089] Figure 6 A graph is shown of the filter load value (%) on the y-axis versus the normalized pressure difference (kPa) on the x-axis for different inlet restriction values. Figure 6 The first filter load curve 602 corresponding to the first inlet restriction value, the second filter load curve 604 corresponding to the second inlet restriction value, and the third filter load curve 606 corresponding to the third inlet restriction value are shown. Figure 6 It shows how the normalized value of δ-P maps to different filter load values given different inlet restriction values.

[0090] As described above, by setting a predetermined inlet restriction value, an applicable curve can be selected, and from this curve, the filter load value can be determined based on the normalized δ-P value. For example, curve 602 can correspond to the inlet restriction value of device 200 when device 200 is operating in free air without an attached tool. In one example, this is a predetermined inlet restriction value set by arranging device 200 in a calibration mode. Curves 604 and 606 can correspond to devices operating in free air with different respective attached tools. Thus, in such an example, to determine the initial filter load value, the value of the normalized δ-P is measured, and the measurement of the normalized δ-P and curve 602 are used to determine the filter load value.

[0091] Examples of the above method can allow the filter load value to be determined based on a correspondence between the filter load value and the operating parameters of the motor. In some examples, this can allow the filter load value to be determined without using additional sensors (such as pressure sensors upstream and downstream of the filter). Additionally, the method can contribute to controlling the overall computational efficiency of device 200 because the parameters required to determine the filter load can also be used for other purposes, such as controlling the input power of the motor.

[0092] The filter load value can be used for various purposes. For example, the filter load value can be determined at regular intervals during device operation, for example, for a control method of the device, such as controlling the input power of the motor. Additionally, the filter load can be continuously monitored so as to provide an alert when the value reaches a threshold indicating that the filter needs to be cleaned or replaced.

[0093] Figure 7 A schematic diagram of a system including an air moving device 200 and a control device 750 according to one example is shown. In this example, aspects of the method for determining the initial filter load value are performed by device 200, while other aspects of the method are performed by control device 750. The air moving device 200 can include any of the features described above with respect to the previous figures. The control device 750 is a device that communicates with the air moving device 200, for example, via a suitable communication protocol such as Bluetooth or NFC. The control device 750 includes a processor 752 and a memory 754. The memory 754 includes machine-readable instructions for causing the control device 750 to perform certain aspects of the example methods described herein.

[0094] In one example, when the air moving device 200 is arranged in a calibration mode, for example, in response to the device 200 detecting that the filter has been replaced, the air moving device 200 can notify the control device 750. In response to receiving the notification that the air moving device 200 is arranged in a calibration mode, the control device 750 can prompt the user to perform certain tasks, such as arranging the device to have a predetermined inlet restriction value, such as removing all tools from the device 200. The control device 750 can also be configured to receive an indication from the user, for example, to confirm that the user has removed all tools from the device 200. The control device 750 can also be configured to provide commands or instructions to the device 200. For example, the control device 750 can indicate to the device 200 when the user has confirmed that all tools have been removed from the device. In response, the device 200 can continue other aspects of the method, including operating the device 200 to determine an operating parameter value and determining an initial filter load value based on the operating parameter value. In other examples, other aspects of the present invention can be performed by the control device 750. For example, certain processing involved in determining the initial filter load value can be performed by the control device 750 or another device in communication with the control device 750 (e.g., a cloud computing device).

[0095] The above-described embodiments should be understood as illustrative examples of the present invention. Other embodiments are contemplated. It should be understood that any feature described with respect to any one embodiment can be used alone, or in combination with other features described, and can also be used in combination with one or more features of any other embodiment, or in combination with any combination of any other embodiments. Additionally, equivalents and modifications not described above can also be employed without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A method for determining an initial filter load value of an air moving device, the method comprising: Arranging the device in a calibration mode that sets a predetermined inlet restriction value for the device; Operating the device in the calibration mode; During the operation, performing a measurement process to determine a first value of an operating parameter of the device, the first value of the operating parameter depending on the filter load level of the installed filter; And Performing a determination process to determine the initial filter load value based on a first predetermined relationship between the value of the operating parameter and a set of filter load values.

2. The method according to claim 1, wherein in the calibration mode, the predetermined inlet restriction value is set by no tool being attached to the device or by a predetermined tool attached to the device.

3. The method according to claim 1 or 2, comprising: In the calibration mode, prompting the user to arrange the device with the predetermined inlet restriction value, or instructing the device to be arranged with the predetermined inlet restriction value.

4. The method according to claim 3, wherein the prompting includes prompting the user to remove all tools from the device, or indicating that no tool is attached to the device.

5. The method according to any one of claims 1 to 4, comprising: In the calibration mode, receiving an indication that the device is arranged with the predetermined inlet restriction value.

6. The method according to claim 5, wherein receiving the indication includes: Detecting that the device is arranged with the predetermined inlet restriction value.

7. The method according to claim 5, wherein receiving the indication includes: Receiving an indication from the user.

8. The method according to any one of claims 1 to 7, wherein the operating parameter is: The operating pressure of the motor of the air moving device; or The speed of the motor of the air moving device.

9. The method according to claim 8, wherein the operating parameter is the operating pressure of the motor of the air moving device, and the first value of the operating parameter is the first value of the operating pressure of the motor, and wherein the measurement process includes determining the first value of the operating pressure of the motor based on: Ambient pressure measurement; and Motor inlet pressure measurement during motor operation.

10. The method according to claim 9, wherein the ambient pressure measurement and the motor inlet pressure measurement are measured by a single pressure sensor at different times.

11. The method according to claim 8, wherein the operating parameter is the operating pressure of the motor of the air moving device, and the first value of the operating parameter is the first value of the operating pressure of the motor, and wherein the measurement process includes determining the first value of the operating pressure of the motor based on: A first pressure measurement of the pressure upstream of the motor; and A second pressure measurement of the pressure downstream of the motor.

12. The method according to any one of claims 1 to 11, wherein the determination process includes: Selecting the first predetermined relationship based on the predetermined inlet restriction value.

13. The method according to any one of claims 1 to 12, wherein the determining process includes normalizing a first value of the operating parameter by using one or more values of one or more corresponding normalization parameters to determine a first normalized value of the operating parameter, and wherein during the determining process: The first predetermined relationship is a relationship between the normalized value of the operating parameter and the filter load value; and an initial filter load value is determined based on the first normalized value of the operating parameter.

14. The method according to claim 13, wherein the one or more normalization parameters include one or more of the following: ambient pressure; ambient temperature; motor input power; and manufacturing tolerances of the air moving device.

15. The method according to any one of claims 1 to 14, wherein in response to replacement of a filter of the air moving device, the device is arranged in the calibration mode.

16. The method according to claim 15, wherein the replacement of the filter of the air moving device is a replacement of the filter after a filter cleaning event.

17. The method according to claim 16, wherein the filter cleaning event is performed in response to the device issuing a filter cleaning alert to the user.

18. A set of machine-readable instructions that, when executed by one or more processors, cause the method according to any one of claims 1 to 17 to be performed.

19. An air moving device, comprising: A processor; And A memory including a set of machine-readable instructions that, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 17.

20. The air moving device according to claim 19, wherein the air moving device is a vacuum cleaner.

21. A system including one or more processors and a memory, the memory including a set of machine-readable instructions that, when executed by at least one of the one or more processors, cause at least one of the one or more processors to perform the method according to any one of claims 1 to 17.

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