Method for determining the degree of loading of a particle filter device of a household appliance

Abstract

The invention relates to a method for determining the degree of filling (expected degree of filling) of a particle filter device of a household appliance, preferably a laundry treatment appliance. During operation of the household appliance, process fluid is passed at least temporarily through the particle filter device, wherein a variable is determined, and the degree of filling (expected degree of filling) of the particle filter device is determined based on the variable. For this purpose, a process variable is used as the variable, which is dependent on the flow behavior of the process fluid as it passes through the particle filter device.

Description

[0001] The invention relates to a method for determining the loading level of a particle filter device of a household appliance, preferably a laundry treatment appliance. During operation of the household appliance, process fluid is passed at least temporarily through the particle filter device. A variable is determined, and the loading level of the particle filter device is determined based on the variable. Furthermore, the invention relates to a control device, a computer program product, and a data carrier.

[0002] Due to the increased environmental pollution with microplastics, a wide variety of measures have been taken in recent years to reduce or prevent microplastics. While the use of microplastic particles in personal care products such as creams, shower gels, and even toothpaste has been reduced wherever possible to reduce microplastic contamination of wastewater, modern laundry treatment appliances often employ particle filter systems that can separate microplastics from a process fluid being pumped out or recirculated by the respective laundry treatment appliance. This can reduce microplastic contamination of wastewater, for example, when washing synthetic clothing containing plastics such as polyacrylic or polyester.In order to always ensure reliable separation of particles from the process fluid via the respective particle filter device, a loading level of the particle filter device is usually monitored, whereby cleaning or replacement of the particle filter device is usually initiated or requested once a certain loading level is detected.

[0003] DE 10 2017 215 132 A1 discloses a method for determining the loading level of a particle filter device of a household appliance. The household appliance can be a washing machine, in which process fluid in the form of wash water is passed through the particle filter device during pumping to separate microplastics from the wash water. The household appliance can also be a tumble dryer, in which the process fluid is circulated as process air and passed through the particle filter device to separate particles from the process air.In one variant of DE 10 2017 215 132 A1, an expected load level is calculated by using a spectrometer to determine the textile type and quantity of the textiles in the laundry treatment appliance. These parameters are then used to determine the expected load level of the particle filter device. In another variant of DE 10 2017 215 132 A1, however, the load level of the particle filter device is determined directly at the particle filter device by providing a spectrometer on the particle filter device, which can detect particles deposited on the particle filter device and thus determine the load level of the particle filter device.

[0004] Based on the prior art described above, it is the object of the present invention to determine the degree of loading of a particle filter device in a household appliance with the lowest possible effort, while at the same time making this determination of the degree of loading as reliable as possible.

[0005] This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow each of these claims provide advantageous developments of the invention. A control device by means of which a method according to the invention can be carried out is further the subject of claims 10 and 11. Furthermore, claim 12 relates to a computer program product, while claim 13 relates to a data carrier.

[0006] According to the invention, a method is used to determine the loading level of a particle filter device of a household appliance during the operation of which process fluid is at least temporarily passed through the particle filter device. Within the scope of the method according to the invention, a variable is determined, and the loading level of the particle filter device is determined based on the variable.

[0007] The household appliance in which the method according to the invention is applied is preferably a laundry treatment appliance, whereby this laundry treatment appliance can specifically be embodied as a washing machine, tumble dryer, or washer-dryer. The household appliance comprises a particle filter device designed to filter particles from a process fluid used during operation of the household appliance to perform a function of the household appliance. To separate particles from the process fluid, the fluid is passed through the particle filter device at least temporarily, i.e., at least during certain process steps of the household appliance.If the household appliance is designed as a washing machine, the process fluid is preferably in the form of a liquid in the form of water or washing liquor, with the liquid being passed through the particle filter device, in particular when the liquid is pumped out, preferably from a washing machine's tub. In contrast, if the household appliance is designed as a tumble dryer, the process fluid is process air, which, if the tumble dryer is designed as a condensation or heat pump dryer, is circulated at least during individual process steps and is passed through the particle filter device during this circulating process. If the household appliance is designed as a washer-dryer, however, the process fluid can be in the form of water, washing liquor, or process air, depending on the process step of the washer-dryer.

[0008] The particle filter device preferably serves to separate particles from the process fluid passed through the particle filter device, for which purpose the process fluid is passed through one or more filter elements in the particle filter device. This preferably takes place at least in certain process steps of the household appliance. The particle filter device is particularly preferably designed to separate particles in the form of microplastic particles from the process fluid.

[0009] Within the scope of the method according to the invention, a variable is determined, whereby this determined variable is subsequently used to determine the loading level of the particulate filter device. Within the meaning of the invention, the variable can be determined in particular by detection via a corresponding sensor or by calculation, for example, from another detected or otherwise known variable. The loading level is preferably determined from the determined variable mathematically, whereby this determination can be made approximately in the sense of an estimate.

[0010] The invention now includes the technical teaching that a process variable is used as the variable, which is dependent on the flow behavior of the process fluid as it is passed over the particulate filter device. In other words, a process variable is used as the variable on the basis of which the loading level of the particulate filter device is determined, wherein the process variable used is dependent on the flow behavior with which the process fluid is passed over the particulate filter device.

[0011] The inventive method for determining the loading level of the particulate filter device has the advantage that, by using the process variable dependent on the flow behavior of the process fluid through the particulate filter device, the loading level of the particulate filter device can be reliably determined, since the flow behavior of the process fluid through the particulate filter device also changes with increasing loading. Thus, a change in the flow behavior due to the dependency also leads to a change in the process variable. This can be achieved with greater accuracy than when determining the loading level based on a variable such as the textile properties or textile quantity.However, additional sensors that detect the loading level directly at the particle filter device can be dispensed with, whereby the method according to the invention can be implemented with little effort.

[0012] The fact that the process variable is dependent on the flow behavior means, in the sense of the invention, that the process variable is dependent on the flow of the process fluid through the particulate filter device. Therefore, a change in the flow of the process fluid through the particulate filter device also results in a change in the process variable. Since the loading of the particulate filter device, in turn, influences the flow of the process fluid through the particulate filter device, the flow of the process fluid changes with the loading of the particulate filter device, and thus also the process variable. From this, it can be concluded that by determining the process variable, the desired conclusion regarding the loading level of the particulate filter device is ultimately also possible.

[0013] According to one embodiment of the invention, a pressure loss occurring at the particle filter device when the process fluid is passed through the particle filter device is used as the process variable. This provides a suitable process variable for determining the loading level, since the pressure loss occurring across the particle filter device and the loading level of the particle filter device are correlated.

[0014] Alternatively, one possible embodiment of the invention is to use an operating parameter of a pump, via which the process fluid is conveyed to the particulate filter device, as the process variable. This also allows a suitable conclusion to be drawn about the loading level, since the operating behavior of a pump conveying the process fluid through the particulate filter device also changes with a change in the loading level. Particularly preferably, the operating parameter is a value of a supply current of a motor of the pump.

[0015] According to a further embodiment of the invention, when determining the loading level, a sum of changes experienced by the process variable over each individual flow cycle of the process fluid through the particulate filter device is continuously calculated. Subsequently, by summing the changes in the process variable, the increasing change in the loading level is also taken into account during the determination, whereby the loading level of the particulate filter device can be determined and tracked even over multiple runs of the household appliance.

[0016] In a further development of the aforementioned embodiment, a respective change in the process variable is determined by integrating the process variable of individual control cycles. This allows a change in the process variable to be easily determined mathematically based on individual control cycles.

[0017] Alternatively or in addition to the aforementioned embodiment, to determine the loading level, a level and / or a profile of the process variable in at least individual control cycles of the process fluid through the particulate filter device is considered. Thus, a conclusion about the loading level of the particulate filter device can be drawn based on the level of the process variable, particularly at the beginning of the individual control cycle, and / or based on a profile of the process variable during the respective control cycle.

[0018] In a further embodiment of the invention, the determined load level is compared with a limit value, with at least one measure being initiated if the limit value is exceeded. The determination of the load level can thus advantageously be used to implement one or more different measures from a defined load level, in particular to ensure continued proper operation of the household appliance in the future. Thus, in a further development of this embodiment, a message is output on a display of the household appliance as a measure to alert an operator of the household appliance that the particle filter device needs to be replaced or cleaned at least in the near future.

[0019] The invention also relates to a control device for a household appliance, which is in particular a laundry treatment appliance and in which a process fluid is at least temporarily passed through a particle filter device. This control device is designed to determine a loading level of the particle filter device of the household appliance and, in the course of this, to determine a process variable which is dependent on a flow behavior of the process fluid as it is passed over the particle filter device. Furthermore, the control device is designed to determine the loading level of the particle filter device based on the determined process variable. Furthermore, the control device can then also be designed to implement one or more of the aforementioned variants of a method according to the invention for determining a loading level of a particle filter device.

[0020] The method according to the invention can also be embodied as a computer program product which, when running on a processor, for example a processor of an aforementioned control unit, instructs the processor via software to perform the associated method steps according to the invention. In this context, the subject matter of the invention also includes a computer-readable medium on which a computer program product described above is stored in a retrievable manner.

[0021] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. It shows: Fig. 1 is a schematic view of a laundry treatment appliance; Fig. 2 a flow diagram of a method for determining a loading level of a particle filter device of the laundry treatment appliance from Fig. 1, according to a first embodiment of the invention; Fig. 3 a flow diagram of a method for determining a loading level of the particle filter device of the laundry treatment appliance from Fig. 1, according to a second embodiment of the invention; and Fig. 4 an exemplary diagram of different courses of a pressure drop occurring at the particle filter device during a pumping cycle.

[0022] Out of Fig. 1 shows a schematic view of a laundry treatment appliance 1, which can specifically be a washing machine or a washer-dryer. The laundry treatment appliance 1 comprises an appliance housing 2, in which a drum 3 is rotatably mounted. The drum 3 serves to hold laundry items to be treated, wherein process fluid in the form of liquid can be fed to the drum 3 via a supply line 4 for treating the laundry items introduced. For this purpose, the supply line 4 connects the drum 3 to a dispensing tray 5, in which supplied water can be mixed with detergent or washing aid before the liquid is fed to the drum 3 via the supply line 4. Thus, the liquid fed to the drum 3 can be, in addition to water, also in particular, washing liquor.

[0023] At the end of a process step or the laundry treatment, the liquid can be pumped out. This pumping is carried out by a pump 6, via which the liquid to be pumped out is first conveyed to a particle filter device 7 before the liquid is then discharged from the device housing 2 of the laundry treatment device 1 via a pumping line 8. Particles can be separated from the pumped-out liquid via the particle filter device 7 before it is discharged, with particular emphasis on removing microplastic particles that have been introduced into the liquid during the laundry treatment.

[0024] The operation of the laundry treatment appliance 1 is controlled in this case via a control unit 9, wherein the control unit 9 in this context also initiates the operation of the pump 6 and thus the pumping of the liquid to the particle filter device 7. In this case, the control unit 9 is then also able to determine a loading level of the particle filter device 7 in order to inform an operator of the laundry treatment appliance 1 at an early stage about the need to clean or replace components of the particle filter device 7. The control unit 9 can determine the loading level in the context of a first variant of a method according to the invention, the flow diagram of which is shown in Fig. 2 is shown.

[0025] The Fig. The first variant of the method according to the invention shown in Figure 2 is initiated at the start of operation of the pump 6 via the control unit 9, wherein in a first step S1 a process variable is determined which is dependent on the flow behavior of the liquid when pumping out via the pump 6 and when passing through the particle filter device 7. In the case of the process shown in Fig. 2, the process variable is a pressure loss delta_p occurring during pumping at the particulate filter device 7. This pressure loss delta_p can be determined by the control unit 9, for example, using appropriate pressure sensors or the like. Alternatively, the process variable can be in the form of an operating parameter of the pump 6, such as a value of a supply current of a motor of the pump 6.

[0026] In a step S2 following step S1, the control unit 9 then evaluates the data from step S1 by integrating the pressure loss delta_p for individual pumping cycles and storing it in the form of a scalar substitute variable drainingScalar according to the following relationship: drainingScalar=∫t_begin_drainingt_end_drainingdelta_p dt

[0027] Subsequently, in a step S3, after each pumping cycle n, the values ​​for the substitute variable drainingScalar are continuously added up and an expected degree of filling expectedDegreeOfFilling of the filter device 7 is formed from the sum thus formed: expectedDegreeOfFilling=∑n=1n(drainingScalar(n))

[0028] As a result, the information about the loading of the filter device 7 from the previous pumping cycles is also stored for the expected loading level expectedDegreeOfFilling. In a further step S4, the expected loading level expectedDegreeOfFilling is then compared with a threshold value threshold_expectedDegreeOfFilling. If this threshold value threshold_expectedDegreeOfFilling is exceeded, the process proceeds to step S5. Otherwise, the process proceeds to step S6, in which the process is initially terminated and only restarted the next time the pump 6 is started up.

[0029] In step S5, however, the control unit 9 performs a measure by displaying a message on the laundry treatment appliance indicating the necessary cleaning or replacement of components of the particle filter device 7. Subsequently, the process is also initially terminated and only restarted the next time the pump 6 is started up.

[0030] Alternatively or in addition to the aforementioned first variant of the method, the control unit 9 can also carry out a second variant of the method, wherein a flow chart of this second variant is shown in Fig. 3. Here, at the start of commissioning of the pump 6 and thus at the start of a pumping cycle, a level and a profile of a process variable are observed in a step S7, wherein the process variable is again a variable that depends on the flow behavior of the liquid during pumping via the pump 6 and during conveyance via the particulate filter device 7, such as, for example, the pressure loss delta_p occurring at the particulate filter device 7. Based on the level and profile of this process variable, the degree of loading of the particulate filter device 7 is then estimated by the control unit 9 in a further step S8.

[0031] In Fig. 4 shows examples of different pressure loss curves delta_p. While the two lower curves in Fig.4 each show a pressure loss curve at a low loading level of the particle filter device 7 and at different loading of the particle filter device 7 taking place during the respective pumping cycle, the uppermost curve shows a pressure loss curve when the particle filter device 7 is already heavily loaded at the beginning of the respective pumping cycle. This can be seen here by the high level already at the beginning and the further increase during the respective pumping cycle.

[0032] Depending on the assessment from step S8, the control unit 9 then proceeds to step S5 following step S8, thereby generating a message, or proceeds to step S6. In this case, the control unit 9 could implement the second variant in addition to the first variant of the method according to the invention. Furthermore, within the scope of the second variant of the method according to the invention, an operating parameter of the pump 6 could again be used as a process variable, such as, for example, a value of a supply current of a motor of the pump 6.

[0033] By means of the method according to the invention, a determination of the loading level of a particle filter device in a laundry treatment appliance can be carried out with little effort and, at the same time, the loading level can be reliably determined. List of reference symbols: 1 laundry treatment device 2 device housings 3 drums 4 Inlet line 5 Dispensing tray 6 Pump 7 Particle filter device 8 Pump line 9 Control unit delta_p pressure loss drainingScalar replacement size expectedDegreeOfFilling expected degree of filling threshold_ expectedDegreeOfFilling Expected degree of filling threshold S1 to S8 single steps QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 215 132 A1

[0003]

Claims

[1] Method for determining a degree of filling (expectedDegreeOfFilling) of a particle filter device (7) of a household appliance, preferably a laundry treatment appliance (1), wherein during operation of the household appliance, process fluid is at least temporarily passed over the particle filter device (7), and wherein a variable is determined and the degree of filling (expectedDegreeOfFilling) of the particle filter device (7) is determined based on the variable, characterized by that a process variable is used as the variable which is dependent on a flow behavior of the process fluid when passing over the particle filter device (7). [2] Method according to claim 1, characterized by that a pressure loss (delta_p) occurring at the particle filter device (7) when the process fluid is passed over the particle filter device (7) is used as the process variable. [3] Method according to claim 1, characterized bythat an operating parameter of a pump is used as the process variable, via which the process fluid is conveyed to the particle filter device. [4] Method according to claim 3, characterized by that the operating parameter is a size of a supply current of a motor of the pump. [5] Method according to one of the preceding claims, characterized by that when determining the degree of filling (expectedDegreeOfFilling), a sum of changes is continuously formed which the process variable experiences over each individual control cycle of the process fluid via the particle filter device (7). [6] Method according to claim 5, characterized by that a respective change in the process variable is determined by integrating the process variable of individual control cycles. [7] Method according to one of the preceding claims, characterized bythat in order to determine the degree of loading, a level and / or a course of the process variable in at least individual guide cycles of the process fluid via the particle filter device (7) is considered. [8] Method according to one of the preceding claims, characterized by that the determined degree of filling (expectedDegreeOfFilling) is compared with a limit value (threshold_ expectedDegreeOfFilling), whereby at least one measure is initiated if the limit value (threshold_ expectedDegreeOfFilling) is exceeded. [9] Method according to claim 8, characterized by that as a measure a message is displayed on the display of the household appliance. [10] Control device (9) for a household appliance, in particular for a laundry treatment appliance (1), wherein the control device (9) is designed to determine a degree of filling (expectedDegreeOfFilling) of a particle filter device (7) of the household appliance, at which a process fluid can be guided at least temporarily over the particle filter device (7), wherein the control device (9) is designed to determine a process variable which is dependent on a flow behavior of the process fluid when guided over the particle filter device (7), and wherein the control device (9) is designed to determine the degree of filling (expectedDegreeOfFilling) of the particle filter device (7) on the basis of the determined process variable. [11] Control device (9) according to claim 10, which is further configured to carry out a method according to one or more of claims 2 to 9. [12] Computer program product for a control unit (9) according to claim 10 or 11, by means of which a method according to one or more of claims 1 to 9 can be carried out, wherein a routine for determining the degree of filling (expectedDegreeOfFilling) of the particle filter device (7) is implemented by corresponding control commands stored in software. [13] A data carrier comprising a computer program product according to claim 12.

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