Method for determining filter load value of filter of mobile air equipment

Abstract

A method of determining a filter load value for a filter of an air moving device includes performing a measurement procedure including determining a first value of an operating parameter of the air moving device, the first value being an operating parameter value when the air moving device is operating at a first inlet limit condition. The method includes performing a determination process to determine a filter load value of the air mobile device filter. The determining process includes determining a filter load value based on a first value of the operating parameter and a first predetermined relationship that associates the operating parameter value with the filter load value when the air mobile device is operating at the first inlet restriction.

Description

Technical Field

[0001] The present invention relates to a method of determining a filter loading value of an air moving device filter, a set of machine-readable instructions for causing the method to be performed, and an air moving device having a memory including such instructions and a processor configured to perform the method by executing the instructions. Background Art

[0002] It is generally desirable to improve air moving devices, such as vacuum cleaners, in a variety of ways. For example, improvements may be needed in terms of efficiency, manufacturing costs, flexibility of use, and reliability. Summary of the invention

[0003] According to a first aspect of the present invention, a method for determining a filter load value of a filter of an air moving device is provided, the method comprising: performing a measurement process, the measurement process comprising determining a first value of an operating parameter of the air moving device, the first value being a value of the operating parameter when the air moving device operates with a first inlet restriction condition; and performing a determination process to determine a filter load value of the filter of the air moving device, the determination process comprising determining the filter load value based on the first value of the operating parameter and a first predetermined relationship, the first predetermined relationship associating the operating parameter value with the filter load value when the air moving device operates with the first inlet restriction condition.

[0004] The filter load may be the load level of the filter filtering particulate matter from the airflow through the motor. For example, the filter load may be the load level of the pre-motor filter. The load level may define a dynamic restriction on the airflow provided by the filter, such as due to dust collected by the filter obstructing the airflow.

[0005] Determining a filter loading value based on a first predetermined relationship between an operating parameter value and a filter loading value when the air moving device is operating under given inlet restriction conditions can allow for robust and accurate determination of the filter loading value based on observable parameters of the device that are related to the filter loading value. It can also allow for filter loading values ​​to be obtained based on measurements of operating parameters without, for example, introducing to the device the ability to directly measure the pressure across the filter to determine the level of filter loading. The method can allow for flexible determination of filter loading values ​​by using operating parameters that are obtained during operation of the device for other purposes and that can be reused to determine the filter loading value. Because the first predetermined relationship takes into account the inlet restriction in the relationship between the operating parameter value and the filter loading value, the first predetermined relationship allows for an accurate and reliable manner of converting the operating parameter value into a filter loading value under a variety of different inlet restriction conditions.

[0006] The operating parameter may be: an operating pressure of a motor of the air moving device; a speed of the motor of the air moving device; or an air flow rate through the motor of the air moving device.

[0007] Determining a 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 an observable physical parameter that is related to the filter load value in a predetermined manner. The operating pressure of the motor and the speed of the motor can both be parameters that can be reliably measured and can be determined for other purposes, such as for monitoring the power output of the device. Therefore, using these parameters to determine the filter load value can avoid the need for additional sensors or processing to perform this task.

[0008] The operating parameter may be an operating pressure of a motor of the air moving device, and the first value of the operating parameter may be a first value of the operating pressure of the motor, and the measurement process may 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.

[0009] Determining a first operating pressure value based on an ambient pressure measurement and a motor inlet pressure measurement during motor operation can provide that the first operating pressure value is an operating pressure differential that correlates to the filter loading level in a reliable and accurate manner under given inlet restriction conditions. It can also allow measurements made for other purposes related to 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.

[0010] The ambient pressure measurement and the motor inlet pressure measurement may be measured by a single pressure sensor at different times.

[0011] Measuring the ambient pressure measurement and the motor inlet pressure measurement at different times by a single pressure sensor may allow a first value of the operating pressure to be obtained by using a single pressure sensor. This may allow the operating pressure to be measured in a cost and space efficient manner.

[0012] The operating parameter may be an operating pressure of a motor of the air moving device, and the first value of the operating parameter may be a first value of the operating pressure of the motor, and the measurement process may include determining the first value of the operating pressure of the motor based on: a first pressure measurement of the pressure at a first location in a motor assembly where the motor is located; and a second pressure measurement of the pressure at a second location in the motor assembly; wherein the second location is downstream of the first location.

[0013] Using a pressure measurement upstream of the motor and a pressure measurement downstream of the motor may allow an accurate and reliable measurement of the operating pressure to be obtained in a simple manner.

[0014] The first inlet restriction condition may indicate a minimum value of an inlet restriction of the air moving device.

[0015] Determining the filter loading by using a value corresponding to the minimum value of the inlet restriction of the air moving device can provide a reliable mapping between operating parameter values ​​and filter loading values.

[0016] The first value may be a minimum value of the operating parameter.

[0017] Using minimum values ​​of operating parameters to obtain filter load values ​​may allow filter load values ​​to be determined efficiently and reliably by using parameters that map to filter load values ​​in a consistent and robust manner.

[0018] Determining the first value of the operating parameter may include: determining a plurality of values ​​of the operating parameter; determining a distribution of the plurality of values ​​of the operating parameter; determining a first property of the distribution; and determining the first value of the operating parameter based on the first property of the distribution.

[0019] This may provide an efficient way of obtaining a first value of the operating parameter which maps well to the filter loading value. By determining the first value based on a distribution property of the operating parameter values, predetermined information about a probability distribution of inlet restriction values ​​of the air moving device during operation may be taken into account in order to correspond the first value to a predetermined value of the inlet restriction.

[0020] A first property of a distribution may be the minimum value in the distribution.

[0021] The minimum value in the distribution can be determined efficiently and can be well correlated with the filter load value.

[0022] The distribution of operating parameter values ​​may be a rolling distribution.

[0023] This can facilitate updating the determination of the filter load value during operation of the air moving device. For example, by considering only operating parameter values ​​from a recent given time frame when determining the filter load value, changes in the distribution properties can be determined that may indicate changes in the filter load value, while the determination of the filter load value can still be reliably obtained based on the distribution of values.

[0024] The first inlet restriction condition may be an inlet restriction condition of the air moving device when operating under predetermined operating conditions.

[0025] This may help improve the determination of the filter loading value using determinations or assumptions regarding the device operating conditions.

[0026] The predetermined operating condition may be indicative of the type of tool attached to the device.

[0027] The type of tools attached to the equipment may be a factor influencing the equipment's access restrictions.

[0028] The method may include selecting a first predetermined relationship based on predetermined operating conditions.

[0029] By taking into account the operating conditions of the device, this can allow a more reliable and accurate determination of the filter load value. For example, if it is determined that a given tool is attached to the device, the first predetermined relationship can be selected as a relationship applicable to predetermined operating conditions, such as when a given tool of a given type is attached to the device.

[0030] The method may include detecting a transition between a first predetermined operating condition and a second predetermined operating condition based on a change in a first value of an operating parameter.

[0031] This may allow a change in the first value to be used to detect a change in the operating condition of the device. This may allow steps to be taken based on the determination, such as selecting a predetermined condition associating an operating parameter value with a filter load value that is appropriate for the new operating condition of the device.

[0032] The determination process may include determining a first normalized value of the operating parameter by normalizing the first value of the operating parameter using one or more values ​​of one or more respective normalization parameters, and in the determination process: the first predetermined relationship may be between the normalized value of the operating parameter and the filter load value; and the determination of the filter load value may be based on the first normalized value of the operating parameter.

[0033] Normalizing operating parameter values ​​using one or more normalization parameters can provide an efficient way to obtain values ​​that are robustly and accurately mapped to filter loading values ​​of air moving devices.

[0034] The one or more normalized parameters may include one or more of: ambient pressure; ambient temperature; motor input power; and manufacturing tolerances of the air moving device.

[0035] These parameters may be readily determined, such as by using sensors, or may be predetermined, such as by a calibration procedure.Normalizing the operating parameter value using these parameters may provide a first value of the operating parameter to effectively map to a filter loading value.

[0036] The method may include issuing a filter loading alert to a user of the air moving device based on the determined value of the filter loading.

[0037] This may allow a determined value of the filter load to be used to alert a user to a particular condition of the filter, for example, changing the user that the filter load has reached a threshold at which the filter should be cleaned or replaced.

[0038] According to a second aspect of the invention, there is provided a set of machine readable instructions which, when executed by a processor of an air moving device, cause the air moving device to perform a method according to the first aspect of the invention.

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

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

[0041] Where appropriate, optional features of one aspect of the invention may be equally applied to other aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will now be described, by way of example only, with reference to the following drawings, in which:

[0043] Figure 1 A schematic diagram showing an example motor assembly of an air moving device;

[0044] Figure 2 An example of an air moving device is shown;

[0045] Figure 3 is a flow chart representing a method of determining a filter loading value for an air moving device;

[0046] Figure 4 An example of a graph showing operating pressure values ​​and inlet restriction values;

[0047] Figure 5 Other examples of graphs showing operating pressure values ​​and inlet restriction values;

[0048] Figure 6 schematically illustrates aspects of an example method of determining a filter loading value;

[0049] Figure 7 Schematically shows Figure 6 Other aspects of the example methods shown;

[0050] Figure 8 Schematically shows Figure 6 and 7 Other aspects of the example methods shown;

[0051] Fig. 9A and 9B Shows Figures 6 to 8 Further aspects of the example methods shown;

[0052] Fig.10A schematic diagram showing another example motor assembly of an air moving device;

[0053] Fig.11 A schematic diagram showing another example motor assembly of an air moving device;

[0054] Fig.12 a schematic diagram showing certain components of a motor assembly of an air moving device according to an example; and

[0055] Fig.13 A schematic diagram is shown of certain components of an example motor assembly of an air moving device according to another example. DETAILED DESCRIPTION

[0056] Figure 1 An example schematic diagram of a motor assembly 100 of an air moving device is shown. The motor assembly 100 includes a set of coils 102, a shaft 104 on which magnets (not shown) are mounted, a bearing 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, an ambient temperature sensor 116, and a first pressure sensor 118 are mounted. The motor assembly 100 includes a housing 124 in which other components are housed. The motor assembly 100 also includes a pre-motor filter 126 for filtering air that is drawn into the motor during use.

[0057] Figure 2 An exemplary air moving device 200 including the motor assembly 100 is shown. The 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 used to engage with 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, including 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 does not include any such mechanically operated components. However, a passive tool can include elements such as bristles or the like to help complete 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 for storing machine-readable instructions executed by the processor 208 to control the operation of components of the vacuum cleaner 200 including the motor 100. The machine-readable instructions, when executed, may cause the processor 208 to perform any of the example methods described herein.

[0058] In use, the motor of the motor assembly 100 draws air into the air moving device 200 through the air inlet, through the air moving device 200, and out of the exhaust port. The air is drawn through the device 200 along the air flow path 128, which passes through the inlet duct 202, the dust separation chamber 206, the motor assembly 100, and leaves the device 200 through the exhaust port.

[0059] Back to Figure 1 When the motor is used in the air moving device 200, current is passed through the coil 102, causing a changing magnetic field to be generated. The changing magnetic field is configured to act on the magnets 106 on the shaft 104 to rotate the shaft 104 about its longitudinal axis. This in turn causes the impeller 108 to rotate. Air driven by the impeller 108 is drawn into the air moving device 200 along an air flow path 128. The air flow path 128 enters the motor assembly 100, passes through the pre-motor filter 126 that removes particulate matter from the air, and enters the housing 124 through the air inlet 110. The air flow path 128 continues through the motor to the impeller 108, and after passing through the impeller 108, leaves the motor assembly 100 through the air outlet 112.

[0060] Figure 3 A flow chart representation of an example method 300 of determining a filter loading value for an air moving device 200 is shown.

[0061] The filter load may be the load level of the filter that filters particulate matter from the airflow through the motor. For example, the filter load may be the load level of the pre-motor filter 126. Alternatively, the filter load may be the level of loading the post-motor filter, or the load levels of multiple filters (e.g., pre-motor filter and post-motor filter) may be considered. The load level of the filter may determine how much dust the filter has collected. In an example, this may be represented by the amount of dust that the filter may collect before it is considered to need replacement or cleaning. For example, a filter load of 100% may indicate that the filter has collected a certain amount of dust, and is therefore considered to need replacement or cleaning. A filter load level of 0% may indicate that the filter has not collected dust, for example, because it has been completely cleaned or newly replaced. Typically, during use of the device 200, as air passes through the device, the filter load level may steadily increase, and dust is filtered out of the air.

[0062] The method 300 includes performing a measurement process at block 302, the measurement process including determining a first value of an operating parameter of an air moving device, the first value being a value of the operating parameter when the air moving device is operating at a first inlet restriction condition.

[0063] The operating parameter may be an operating pressure of a motor of air moving device 200 .

[0064] 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 airflow path 128. The operating pressure can be an air pressure differential. The operating pressure can be, for example, a pressure difference between an upstream and downstream location in the motor assembly along the airflow path 128.

[0065] 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 an ambient pressure measurement obtained when the motor is not running (for example, before starting the air moving device 200) and a pressure measurement obtained during motor operation. In some examples described herein, such an operating pressure is referred to as δ-p. The pressure measurement performed during motor operation can be performed, for example, at the air inlet 110. Alternatively, it can be measured at the air outlet of the motor. In some examples, the pressure measurement for obtaining the operating pressure value can be performed by the same pressure sensor. This allows the use of a single pressure sensor to obtain the operating pressure value, which can save cost and space.

[0066] Examples of methods of obtaining operating pressure measurements are described in more detail below.

[0067] In other examples, the operating parameter may be a parameter other than the operating pressure, such as the motor speed of the air moving device 200. The speed may be measured, for example, by a suitable sensor (not shown). In other examples, the operating parameter may be the air flow rate through the device 200. An example of determining the air flow rate is described below.

[0068] The inlet restriction of the air moving device 200 is the level of restriction acting on the air inlet through which air flows into the device 200. The level of inlet restriction can vary based on various factors, such as obstacles that impede the flow of air into the device 200. For example, the inlet restriction can vary depending on the type of surface that the vacuum cleaner 200 is used to clean. For example, a carpeted surface or similar surface may have a greater restriction on the airflow entering the vacuum cleaner 200 than a smooth surface such as a wood or tile surface. The degree of inlet restriction can also vary depending on the type of tool attached to the vacuum cleaner 200. For example, different tools can have different geometries, thereby restricting the airflow entering the vacuum cleaner 200 by different amounts. For example, different tools may have different air inlet diameters. In addition, some tools may include elements that impede the airflow into the device 200, such as bristles for cleaning carpets, while other tools may not include such elements.

[0069] The first inlet restriction condition may indicate a minimum level of inlet restriction for the air moving device 200. For example, the first value of the operating parameter may be a value of the operating parameter measured when the air moving device 200 is operating at a minimum level of inlet restriction, or equivalently, at a maximum equivalent orifice diameter. The minimum level of inlet restriction may correspond to the device 200 operating in free air. That is, the minimum level of inlet restriction may be a level of inlet restriction acting on the device 200 when the tool of the vacuum cleaner is not engaged with a surface, such that there is no external obstruction to the flow of air into the device 200.

[0070] In other examples, the first inlet limit condition may be a known property of the inlet limit value distribution of the device 200. For example, an average or mode inlet limit value may be determined for the device 200 over a period of operation. The first value of the operating parameter may be a value measured when the device 200 is operating at the average or mode inlet limit value.

[0071] The method 300 also includes, at block 304, performing a determination process to determine a value of a filter load of a filter of the air moving device 200. The determination process includes determining the filter load value based on a first value of an operating parameter and a first predetermined relationship that relates the operating parameter value to the filter load value when the air moving device 200 is operating at a first inlet restriction condition.

[0072] The first predetermined relationship may include a relationship defined by a curve relating the operating parameter value of the motor to the inlet restriction value of air moving device 200 .

[0073] The relationship between the operating parameter value and the inlet restriction value can be obtained, for example, through a calibration process. The calibration process can include, for example, operating the device 200 under known operating conditions, including known values ​​of the inlet restriction, and measured values ​​of the operating parameter. This can be achieved by operating the device 200 with an orifice plate having orifices of different diameters that restrict airflow into the device 200. The inlet restriction value of the device in operation can be defined based on the diameter of the orifice that will provide the same level of restriction to the airflow into the device 200. For example, when used to clean carpet surfaces, the vacuum cleaner 200 may be operated at a high level of inlet restriction, which may be equivalent to operating under known conditions in which the orifice plate has a small diameter orifice that restricts airflow into the vacuum cleaner 200. Conversely, when cleaning wood surfaces, the vacuum cleaner 200 may be operated at a lower level of inlet restriction, equivalent to the inlet restriction presented by the larger diameter orifice.

[0074] The operating parameter value of the motor and one or more additional parameter values ​​can be associated with the inlet restriction value of the air moving device through a predetermined relationship. Then, the value of the inlet restriction can be determined based on the first value of the operating parameter and the corresponding values ​​of the one or more other parameters. The other parameters can be parameters of the air moving device 200 that affect the operating parameter value, which is measured for a given value of the inlet restriction. For example, different parameter values, such as ambient pressure, ambient temperature, motor input power, filter loading, and manufacturing tolerances of the air moving device, may result in different operating parameter values ​​for the same inlet restriction value.

[0075] Ambient pressure and ambient temperature constitute part of the external conditions under which the device 200 operates. In some examples, ambient pressure can be measured by first pressure sensor 118 before the motor is started. Ambient temperature can be measured by temperature sensor 116. Motor input power is the power used to drive the motor.

[0076] The motor input power may be controlled by the processor 208 and supply DC or AC power, for example, from a battery (not shown) of the device 200 or from a mains supply. The motor input power may control the suction power of the air moving device.

[0077] The manufacturing tolerances of the air moving device 200 can account for the variability of operation between different devices. For example, during the calibration process after the device is assembled, 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 a device production line, an orifice plate with an orifice of a given diameter is connected to the inlet of the device, where it is known that the device has a clean filter, i.e., a filter load value of 0%. Ambient temperature and pressure are measured. The device is operated at a given power level, and operating parameters, such as δ-P, are measured. Where the input power, ambient temperature, ambient pressure, filter load value are measured or otherwise known, the measured δ-P represents a manufacturing tolerance factor. This process can be repeated at multiple power levels and different orifice diameters.

[0078] In some examples, the normalized value of the operating pressure is obtained by normalizing the operating parameter value relative to one or more other parameters (such as those mentioned above). For example, a five-dimensional lookup table can be defined that maps corresponding values ​​of manufacturing tolerance, ambient pressure, ambient temperature, motor input power, and operating pressure value to the normalized value of the operating pressure.

[0079] Figure 4 An example of a curve showing the relationship between the normalized operating pressure and the inlet restriction. This example is a vacuum cleaner motor.

[0080] exist Figure 4In the example of , the operating parameter shown on the y-axis is the operating pressure, i.e. the δ-P value, which defines the difference between the motor ambient pressure before start-up and the pressure at the motor inlet during operation. The unit of δ-P is kilopascals. The inlet restriction value refers to the orifice plate diameter in millimeters. A first curve 402 maps normalized δ-P values ​​to inlet restriction values, the curve being obtained by a suitable calibration process, which involves operating the vacuum cleaner under known conditions, wherein the inlet restriction is provided by orifices of different diameters. The orifice diameter and the corresponding values ​​of δ-P have been measured. The first curve 402 is obtained by normalizing the values ​​of δ-P relative to the values ​​of manufacturing tolerances, ambient pressure, ambient temperature and motor input power. The first curve 402 uniquely maps normalized values ​​of operating pressure to inlet restriction values. However, as will be seen in reference Figure 5 As described, the normalized value of the operating pressure does not take into account the filter load value of the motor. Therefore, different values ​​of the filter load will result in different mappings between the normalized operating pressure value and the inlet restriction value.

[0081] Figure 5 A set of curves 402, 504, 506 are shown which relate normalized values ​​of operating pressure to inlet restriction values. Each curve corresponds to a different filter loading value. Figure 4 The first curve 402 is also Figure 5 , and corresponds to a filter load value of 0%. A second curve 504 corresponds to a filter load value of 50%. A third curve 506 corresponds to a filter load value of 100%. To determine the value of the inlet restriction, a set of curves 402, 504, 506 is used, one of which can be selected based on a given value of the filter load. Then, for a known filter load value, the normalized value of the operating pressure uniquely determines the inlet restriction value.

[0082] Now refer to Figure 6 An example of a determination process for determining a filter load value is described. Figure 6 The above reference Figure 5 A set of normalized delta-P curves 402, 504, 506 are depicted. Figure 6 A first probability distribution 602 of applicable inlet restriction values ​​for a vacuum cleaner is shown. The first probability distribution 602 represents the probability of the vacuum cleaner having a given level of inlet restriction when operated with a first tool connected, based on the equivalent orifice diameter. The first probability distribution 602 corresponds to a passive tool including a relatively wide nozzle and a selectively engageable brush. Figure 6 It can be seen that in this example, the inlet restriction values ​​of the first probability distribution 602 range from about 13 mm to about 47 mm. The minimum level of inlet restriction in the first probability distribution 602 corresponds to an orifice diameter of about 47 mm.

[0083] Figure 6 Also shown are respective projections of the first probability distribution 602 onto the two normalized delta-P curves 402, 506. The first projection 604 is the projection of the first probability distribution 602 onto the first curve 402, which corresponds to a filter loading of 0%, as described above. The second projection 604 is the projection of the first probability distribution 602 onto the third curve 506, which corresponds to a filter loading of 100%, as described above.

[0084] Projections 604, 606 define corresponding probability distributions of measured normalized values ​​of δ-P for filter load values ​​of 0% and 100%, respectively. In other words, the first projection 604 defines the probability of measuring a given normalized value of δ-P when the device is operated at a filter load of 0%. Similarly, the second projection 606 defines the probability of measuring a given normalized value of δ-P when the device is operated at a filter load of 100%. Figure 6 Other projections not shown in can be defined, defining the probability distribution of normalized δ-P at different filter load values ​​(eg, 25%, 50%, 75%, etc.).

[0085] In general, the values ​​of normalized delta-P defined by curves 402, 504, 506 decrease rapidly for small values ​​of orifice diameter, but begin to level out for large values ​​of orifice diameter. This flattening means that a given normalized delta-P value can be uniquely mapped to a given one of curves 402, 504, 506 at high values ​​of orifice diameter. In an example, this property can be used to determine the level of filter loading based on the measurement of normalized delta-p.

[0086] For example, according to the first probability distribution 602, the minimum normalized delta-P value in the known probability distributions 604, 606 corresponds to a device operating at a known maximum orifice diameter, which in this example is approximately 47 mm. To determine the filter loading value, the minimum value of the normalized delta-P during operation of the vacuum cleaner can be measured and mapped to a given one of the curves 402, 504, 506 at the known maximum orifice diameter. By determining which of the curves 402, 504, 506 the measured normalized delta-P value maps to, the filter loading value can be determined.

[0087] For example, in Figure 6, the third curve 506 and probability distribution 606 show that for a filter loading value of 100%, the minimum value of the normalized delta-P corresponding to a maximum orifice diameter value of approximately 47 mm is approximately 15.3 kPa. Therefore, if the minimum normalized value of delta-P for the vacuum cleaner is measured to be approximately 15.3 kPa, this indicates that the filter loading is 100%. Similarly, the first curve 402 and probability distribution 604 show that for a filter loading value of 0%, the minimum normalized delta-P value also corresponding to a maximum orifice diameter value of approximately 47 mm is approximately 11.2 kPa. Therefore, the measurement of a minimum normalized delta-P value of approximately 11.2 kPa indicates a filter loading value of 0%.

[0088] Figure 7 Another example of a method of determining a filter loading value is shown. Figure 7 Similar to Figure 6 , but relates to a vacuum cleaner operated with a second tool attached. Figure 7 A second probability distribution 702 of inlet restriction values ​​applicable when the vacuum cleaner is used with a second tool is shown. Figure 6 As described, Figure 7 The projections 704, 706 of the second probability distribution 702 on the first curve 402 and the third curve 506 are shown. Figure 6 As described, the filter loading value can be determined by measuring the minimum normalized delta-P value of the vacuum cleaner in use. It can then be determined which of a plurality of curves, such as curves 402, 504, 506, the minimum value is mapped to. The curve to which the minimum normalized delta-P value is mapped represents the filter loading value.

[0089] As can be seen from a comparison of the second probability distribution 702 and the first probability distribution 602, the second tool generally provides a higher level of inlet restriction than the first tool. The second tool can, for example, be a passive slit tool. In this example, the minimum level of inlet restriction provided by the second tool corresponds to an orifice diameter of approximately 23 mm, compared to a value of approximately 47 mm for the first tool. Therefore, for a given filter load value, the minimum normalized δ-P value when using the second tool is greater than the minimum normalized δ-P value when using the first tool. For example, when using the second tool, the minimum normalized δ-P value at a filter load of 100% is approximately 16.5 kPa, while the minimum normalized δ-P value at a filter load of 0% is approximately 13.2 kPa. Figure 7 The difference in the minimum normalized delta-P value at 0% filter load when the first tool is used and when the second tool is used is shown by arrows 708. In some examples, this difference in the minimum normalized delta-P value at the same filter load value can be used to determine when a tool attached to the device is replaced.

[0090] Figure 8 The filter loading value on the y-axis and the minimum normalized delta-P value on the x-axis are shown. Figure 8 A first filter loading curve 802 corresponding to a first tool and a second filter loading curve 804 corresponding to a second tool are shown. Figure 8 It is shown how the minimum normalized value of delta-P maps to a given filter loading value for the first tool and the second tool. Figure 8 The difference 708 between the minimum normalized delta-P values ​​of the first tool and the second tool at a filter load value of 0% is shown. As described above, during use of the device, as the filter collects more dust, the typical filter load value changes gradually. Therefore, unless the operating conditions of the device change, a sudden, relatively large change in the determined value of the filter load is generally not expected. If such a sudden change is detected, then in some examples, such a change can be used to indicate a change in the operating conditions of the device. For example, a sudden change in the determined value of the minimum normalized delta-P detected can be considered an indication of a change in the tool attached to the vacuum cleaner. For example, if the measured minimum normalized delta-P value changes by a difference 708 within a relatively short period of time of use of the device, this can be considered to indicate that the vacuum cleaner has transitioned from an operating state in which the first tool is attached to an operating state in which the second tool is attached. In addition, the correct filter load curve for associating the minimum normalized delta-P value with the filter load value can be determined based on the type of tool attached to the device, for example, if it is known which type of tool is attached to the device. For example, upon detecting a change 708 in the determined minimum normalized delta-P value, the device may move from determining filter load values ​​using the first filter load curve 802 to determining filter load values ​​using the second filter load curve 804 .

[0091] Fig. 9A and 9B Examples of probability distributions 902 , 904 of normalized delta-P values ​​are shown when the apparatus 200 is used with a given tool (eg, a first tool). Fig. 9A Corresponds to the vacuum cleaner being operated at a filter load value of 0%. Fig. 9BCorresponding to a vacuum cleaner operating at a filter load value of 100%. In an example, in order to determine such a probability distribution, a fixed number of counters are defined, for example, 100 counters may be defined. Two one-dimensional arrays are defined, a pressure bin array and a FIFO first-in first-out array. The length of the FIFO array is equal to the fixed number of counters. The delta-P values ​​are measured and normalized. Corresponding to the measured and normalized values, counters are added to the pressure bin. Once all counters are assigned to bins, at the next measurement of normalized delta-P, the earliest assigned counter, which may be the counter in the final position of the FIFO array, is moved to the bin corresponding to the most recently measured normalized delta-P value. In this way, a permanent rolling distribution may be maintained. The rolling distribution may be queried at any time and at any frequency. In an example where the minimum value of the normalized delta-P is determined and used to indicate the filter load value, the lowest filled bin is determined in order to determine the minimum value of the normalized delta-P. In some examples, a minimum counter threshold may be set below which the counters in the bin are not counted, so that the lowest filled bin is the lowest bin with at least a threshold number of counters. This may act as a noise filter. In some examples, the distribution may be filtered, for example by determining an exponential moving average, to further remove noise. In other examples, no FIFO array may be defined, and, for example, once all counters have been allocated, the counters may be removed from the pressure bin and allocation of counters may begin again.

[0092] As an example, Fig. 9A and 9B The minimum normalized delta-P value 906 of the distributions 902, 904 is shown, representing filter loading values ​​of 0% and 100%, respectively. Fig. 9A and 9B Also shown by way of example is a threshold counter value 908 below which the counter is not counted for purposes of determining the lowest filled bin.

[0093] The above examples have been described with reference to two particular tools. However, it should be understood that a variety of different types of tools may be used with the device 200, and each of these different tools may have an associated probability distribution of inlet limit values ​​that may be used in the method of determining filter load values ​​for the device 200. Furthermore, the inlet limit probability distribution for a given tool may vary depending on the application. However, assuming that a given property of the probability distribution (e.g., the minimum level of the inlet limit) does not change, then the given property may be used to determine the filter load regardless of other changes in the overall probability distribution.

[0094] Although in some of the above examples, the minimum value of the operating parameter is the value used to indicate the filter load level, in other examples, other values ​​of the operating parameter can be used to indicate the filter load value. For example, a different property other than the minimum value of the probability distribution of the operating parameter, such as the arithmetic mean, mode, or other property, can be determined and used as the operating parameter value indicating the filter load value.

[0095] The examples of the above methods may allow the filter load value to be determined based on the correspondence between the filter load value and the operating parameters of the motor. In some examples, this may allow the filter load value to be determined without using additional additional sensors (eg, pressure sensors upstream and downstream of the filter).

[0096] The filter load value can be used for various purposes. For example, the filter load value can be used to determine an inlet limit value. In another example, the filter load value can be used to provide an alarm. For example, when the filter load value reaches a given threshold, an alarm can be issued to indicate that the filter should be cleaned or replaced.

[0097] During operation of the air moving device, method 300 may be performed multiple times, for example, at regular intervals. For example, filter load values ​​may be determined at regular intervals for use in control methods of the device, such as controlling the input power to a motor. In addition, filter load may be continuously monitored to provide an alert when the value reaches a threshold indicating a need to clean or replace the filter.

[0098] The method can allow for robust and accurate determination of filter load values ​​and can be performed without adding additional sensors, such as measuring the pressure difference across the filter. In addition, the method can contribute to the overall computational efficiency of the control device 200, since the parameters required to determine the filter load can also be used for other purposes, such as controlling the input power of the motor.

[0099] Fig.10 Another exemplary schematic diagram of a motor assembly 1000 is shown. The motor assembly 1000 includes the same Figure 1 For features corresponding to those of the motor assembly 100 described above, such features are labeled with the same reference numerals where labeled. For clarity, Fig.10 The pre-motor filter is not shown.

[0100] The motor assembly 1000 also includes a second pressure sensor 1020 and a wire 1022 that electrically connects the second pressure sensor 1020 to the circuit board 1014. The motor assembly 1000 also includes an inlet tube 1026 that provides a fluid connection from the second pressure sensor 1020 through the housing 1024 to the inlet 1030 of the impeller 1008. This allows the second pressure sensor 1020 to measure the pressure at the impeller inlet 1030. Fig.10 As can be seen from the schematic diagram, the cross-sectional area of ​​the motor is narrower at the impeller inlet 1030 than at the motor inlet 1010.

[0101] Fig.11 Another example motor assembly 1100 is shown. Fig.11 In the motor assembly 1100, the second pressure sensor 1120 is located outside the circuit board 1114. Fig.10 The motor assembly 1000 is the same as the motor assembly 1000 of FIG. A passage or conduit 1122 provides a fluid connection between the second pressure sensor 1120 and the impeller inlet 1130. The passage 1122 allows the second pressure sensor 1120 to measure the pressure at the impeller inlet 1130 without the second pressure sensor being located at the impeller inlet 1130.

[0102] Such a passage can be provided in a variety of ways. In one example, the passage 1126 can be formed by a conduit. The conduit can, for example, extend along the outer surface of the housing 1124 and extend through a hole 1126 in the housing to provide a fluid connection from the second pressure sensor 1120 to the impeller inlet 1130. At one end of the passage 1126 where the second pressure sensor 1120 is located, an airtight seal can be formed around the second pressure sensor 1120. The seal can, for example, include a circular, EPDM foam seal that seals the conduit to the location on the circuit board 1114 where the second pressure sensor 1120 is located. Fig.10 A similar seal is formed around the second pressure sensor 1020 of the motor assembly 1000 .

[0103] In another example, the passageway may be integral to the housing of the motor assembly. Fig.12 An exemplary schematic diagram of such a housing 1224 is shown, wherein the channel 1222 extends through the housing 1224. In such an example, the housing 1224 can be formed by an injection molding process, and the channel through the housing 1224 is formed during the injection molding, for example, by using removable pins 1230a, 1230b during the injection molding. In use, with reference to Fig.11In the manner described, a hole 1226 through the housing 1224 leads to the impeller inlet of the motor. In use, the second pressure sensor is located at the upstream end 1228 of the channel 1222. This provides a fluid connection to the second pressure sensor via the channel 1222 and allows the second pressure to be configured to measure the pressure at the impeller inlet. This can allow the second pressure sensor to be conveniently positioned. The second pressure sensor can be located, for example, on a circuit board of the device. In addition, it can be cost-effective and convenient to form the channel 1222 integrally with the housing 1224.

[0104] In another example, a channel may be formed between an outer surface of the housing and a mount positioned against the outer surface of the housing. Fig.13 Such an example is schematically illustrated. Fig.13 In the embodiment, a mounting member 1332, for example made of rubber, has a groove 1334 therein. The mounting member 1332 is sealed in an airtight manner to the outer surface of a housing 1324, which has a hole 1326 which, in use, leads to the impeller inlet. The passage 1322 is created by the gap provided by the groove 1334 in the mounting member 1332 between the mounting member 1332 and the outer surface of the housing 1324. Fig.12 and Fig.13 In both examples, in use, the second pressure sensor is hermetically sealed to the channels 1222, 1322 at the upstream ends 1228, 1328 of the channels 1222, 1322. For example, in Fig.13 In the example of FIG. 1 , the mount 1332 may be a rubber mount that forms a seal around the second pressure sensor.

[0105] In each example motor assembly 1000, 1100, a first pressure sensor 1018, 1118 is positioned to take pressure measurements at the air inlet 1010, 1110. The pressure measurements taken by the first pressure sensor 1018, 1118 include the ambient pressure p measured before the motor is started. a Furthermore, the pressure measurements performed by the first pressure sensors 1018, 1118 include measurements of the first pressure p1 performed during operation of the motor. The temperature sensors 1016, 1116 are configured to measure the ambient temperature T a The second pressure sensor 1020, 1120 is configured to measure the second pressure p2 at the impeller inlet 1030, 1130 during operation of the motor. a , the first pressure p1 and the second pressure p2 are each an absolute pressure.

[0106] In an example, measurements taken by the first pressure sensor 1018, 1118, the second pressure sensor 1020, 1120, and the temperature sensor 1016, 1116 may be used to determine a dynamic pressure value. In one example, the dynamic pressure measurement is determined as follows.

[0107] By subtracting the ambient pressure p from the first pressure p1 a To determine the static pressure p in the motor static The first pressure p1 is usually lower than the ambient pressure p a , because the operation of the motor causes a partial vacuum to be created within the motor housing 1024 , 1124 .

[0108] The total instrument pressure p at the impeller inlet is determined by subtracting the second pressure p2 from the first pressure p1 total The total pressure at the impeller inlet is p total From the static pressure p static and dynamic pressure p dyn Due to the smaller cross-sectional area and the associated higher air velocity at the impeller inlet 1030 , 1130 compared to the motor inlet 1010 , 1110 , the second pressure p2 is generally lower than the first pressure p1 .

[0109] Dynamic pressure p at the impeller inlet 1030, 1130 dyn The total pressure p at the impeller inlet 1030, 1130 total Subtract the static pressure p in the motor from static The dynamic pressure p dyn May also be called air velocity pressure.

[0110] The dynamic pressure p dyn , first pressure p1 and temperature T a Input into the density ratio formula to determine the dynamic pressure value p at STP dyn@STP . p dyn@STP The value of is the dynamic pressure value corrected for standard temperature and pressure. The dynamic pressure value is therefore normalized for the ambient conditions in which the motor is operating. This allows, for example, the definition of a single lookup curve relating dynamic pressure values ​​to air flow rate or other parameters. The applicable density ratio for a given motor depends on the type of motor. For example, the following density ratio formulas (1) to (3) apply to constant power motors, AC series motors, and constant speed motors, respectively:

[0111] (1)

[0112] (2)

[0113] (3)

[0114] Among them, p dyn@STP , p1 and p dyn In kPa, T a In degrees Celsius, 101.325 is the standard pressure in kPa, 293 is the standard temperature in Kelvin, and 273.15 is 0 degrees Celsius in Kelvin.

[0115] The determined dynamic pressure value can be mapped to various parameters. For example, the dynamic pressure value can be used as an operating parameter in the above-mentioned example method for determining the filter load value. In such an example, for different filter load values, the dynamic pressure value can be mapped to the inlet restriction value, for example, in a manner similar to the above-mentioned manner for the δ-P value. Additionally or alternatively, the dynamic pressure value can be mapped to the air flow rate value through the motor. In the example of the above method, the air flow rate can also be used as an operating parameter. The mapping of the dynamic pressure value to the air flow rate can be determined, for example, by a calibration process. In such a calibration process, the air moving device can be operated with an air flow rate measuring device, and the air flow rate measuring device can include a bell mouth, a venturi tube or an orifice plate for measuring the air flow rate through the device, while measuring, the measurement allows the determination of the dynamic pressure value corresponding to the air flow measurement. Therefore, when the device is operated after calibration, the dynamic pressure value can be determined and mapped to the air flow rate value to determine the air flow rate through the device in use.

[0116] The above 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 may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other embodiment, or in combination with any combination of any other embodiment. In addition, equivalents and modifications not described above may also be employed without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A method for determining a filter loading value of a filter of an air moving device, the method comprising: performing a measurement process including determining a first value of an operating parameter of the air moving device, the first value being a value of the operating parameter when the air moving device is operating at a first inlet restriction; and A determination process is performed to determine a filter loading value for a filter of the air moving device, the determination process comprising determining the filter loading value based on a first value of an operating parameter and a first predetermined relationship that relates the operating parameter value to the filter loading value when the air moving device is operating at the first inlet restriction condition.

2. The method according to claim 1, wherein the operating parameters are: an operating pressure of a motor of the air moving device; the speed of the motor of the air moving device; Or the air flow rate through the motor of the air moving device.

3. The method of claim 2, wherein the operating parameter is an operating pressure of a motor of the air moving device, and the first value of the operating parameter is a first value of the operating pressure of the motor, and wherein the measuring process comprises determining the first value of the operating pressure of the motor based on: Ambient pressure measurements; and Motor inlet pressure measurement during motor operation. 4 . The method of claim 3 , wherein the ambient pressure measurement and the motor inlet pressure measurement are measured by a single pressure sensor at different times.

5. The method of claim 2, wherein the operating parameter is an operating pressure of a motor of the air moving device, and the first value of the operating parameter is a first value of the operating pressure of the motor, and wherein the measuring process comprises determining the first value of the operating pressure of the motor based on: a first pressure measurement of a pressure at a first location in a motor assembly where the motor is located; and a second pressure measurement of the pressure at a second location in the motor assembly; The second position is downstream of the first position.

6. The method of any one of the preceding claims, wherein the first inlet restriction condition indicates a minimum value of an inlet restriction of the air moving device.

7. A method according to any one of the preceding claims, wherein the first value is a minimum value of the operating parameter.

8. The method according to any one of the preceding claims, wherein determining the first value of the operating parameter comprises: determining a plurality of values ​​for the operating parameter; determining a distribution of a plurality of values ​​of the operating parameter; determining a first property of the distribution; and Based on a first property of the distribution, a first value of the operating parameter is determined.

9. The method of claim 8, wherein the first property of the distribution is a minimum value in the distribution.

10. A method according to claim 8 or 9, wherein the distribution of operating parameter values ​​is a rolling distribution.

11. The method of any one of the preceding claims, wherein the first inlet restriction is an inlet restriction of the air moving device when operating under predetermined operating conditions.

12. The method of claim 11, wherein the predetermined operating condition is indicative of a type of tool attached to the device.

13. The method according to claim 11 or 12, wherein the method comprises: Based on the predetermined operating condition, the first predetermined relationship is selected.

14. The method according to any one of claims 11 to 13, wherein the method comprises: Based on a change in the first value of the operating parameter, a transition between the first predetermined operating condition and the second predetermined operating condition is detected.

15. The method according to any one of the preceding claims, wherein the determining process comprises determining a first normalized value of the operating parameter by normalizing the first value of the operating parameter using one or more values ​​of one or more corresponding normalization parameters, and wherein in the determining process: The first predetermined relationship is a relationship between a normalized value of the operating parameter and the filter load value; and The determination of the filter loading value is based on a first normalized value of the operating parameter.

16. The method of claim 15, wherein the one or more normalization parameters include one or more of the following: Environmental pressures; Ambient temperature; Motor input power; and Manufacturing tolerances of the air moving device.

17. A method according to any one of the preceding claims, comprising: Based on the determined filter loading value, a filter loading alert is issued to a user of the air moving device.

18. A set of machine readable instructions which, when executed by a processor of an air moving device, cause the air moving device to perform the method of any one of claims 1 to 17.

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

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

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