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

Abstract

The invention relates to a method for determining the degree of loading of a particle storage device of a household appliance, wherein at least one variable is determined and the degree of loading of the particle storage device is determined based on the at least one variable. In this case, a state variable of a compression device is used as the variable. In this device, an elastic element of the compression device is expanded upon request for compression of the compressibly designed particle storage device, whereupon the particle storage device is compressed between the elastic element and a surrounding housing of the compression device. Each state variable is dependent on a volume of the particle storage device and is determined during the compression of the particle storage device.

Description

[0001] The invention relates to a method for determining the loading level of a particle storage device of a household appliance, preferably a laundry treatment appliance, wherein at least one variable is determined and the loading level of the particle storage device is determined based on the at least one 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 toothpaste has been reduced wherever possible in order to reduce microplastic contamination of wastewater, particle filter systems are frequently used in modern laundry treatment appliances. These filters can separate particles in the form of microplastics and lint from a process fluid being pumped out or recirculated by the respective laundry treatment appliance. These particles are then usually retained in a particle storage device in the respective particle filter device. 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 and lint from the process fluid via the respective particle filter device, the loading level of the particle storage device is sometimes monitored, whereby cleaning, emptying or replacement of the particle storage 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 storage device in a household appliance. The household appliance can be a washing machine, in which process fluid in the form of wash water is pumped through a particle filter device containing the particle storage device 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, the expected loading level of the particle storage device is calculated by using a spectrometer to determine the textile type and quantity of the textiles in the laundry treatment device. The expected loading level of the particle storage device is then determined based on these parameters. In another variant of DE 10 2017 215 132 A1, however, the loading level of the particle storage device is determined directly at the particle filter device. A spectrometer is provided on the particle filter device, which can detect particles captured by the particle storage device, thus allowing the loading level of the particle storage device to be determined.

[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 storage device in a household appliance with the lowest possible effort, while at the same time being able to determine the degree of loading as accurately 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, in a method for determining a loading level of a particle storage device of a household appliance, preferably a laundry treatment appliance, at least one variable is determined, wherein the loading level of the particle storage device is subsequently determined based on the at least one variable.

[0007] The household appliance in which the method according to the invention is used is preferably a laundry treatment appliance, wherein this laundry treatment appliance can specifically be designed as a washing machine, tumble dryer or washer-dryer. The household appliance has a particle reservoir which is intended to receive particles filtered out of a process fluid of the household appliance, wherein the process fluid is used during operation of the household appliance to carry out a function of the household appliance. In order to separate particles from the process fluid, the latter is preferably passed at least temporarily, i.e. at least in certain process steps of the household appliance, through a particle filter device to which the particle reservoir in particular is assigned.If the household appliance is designed as a washing machine, the process fluid is preferably 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 of 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 storage device is particularly intended to collect and retain particles separated from the process fluid of the household appliance. Preferably, the particle storage device is part of a particle filter device, which serves to separate particles from the process fluid conducted through the particle filter device and in which the process fluid is, in particular, passed through one or more filter elements. This preferably takes place at least in certain process steps of the household appliance. Most preferably, the particle filter device is designed to separate particles in the form of microplastic particles and lint from the process fluid.

[0009] Within the scope of the method according to the invention, at least one variable is determined, wherein this at least one specific variable is then subsequently used to determine the loading level of the particle accumulator. Within the scope of the invention, exactly one variable can be determined, which is then used to determine the loading level of the particle accumulator, although alternatively, it would also be conceivable within the scope of the invention to determine several variables, based on which the loading level is then subsequently determined. In the latter case, the loading level can be determined independently of one another using the respective variable, or at least one further variable can be determined from one variable and this can then be used subsequently to determine the loading level.

[0010] The invention now encompasses the technical teaching that a state variable of a compression device is used as a variable, in which an elastic element of the compression device is expanded upon request for compression of the compressibly designed particle storage device, whereupon the particle storage device is compressed between the elastic element and a surrounding housing of the compression device. Each state variable is dependent on a volume of the particle storage device and is determined during the compression of the particle storage device.

[0011] In other words, the at least one variable is used in the form of a state variable that is assigned to a compression device and is determined during compression of the particle accumulator in the compression device. For compression, the particle accumulator is designed to be compressible, i.e. the particle accumulator can be compressed in the compression device, with the compression being brought about in the compression device via an elastic element that is specifically expanded for compression and thereby compresses the particle accumulator between itself and a surrounding housing of the compression device. The state variable used in each case depends on a volume of the particle accumulator.

[0012] The inventive method for determining the degree of loading of the particle accumulator has the advantage that, by using each state variable of the compression device, the degree of loading of the particle accumulator can be determined at least with a good approximation, since with increasing loading of the particle accumulator, its volume also changes and, consequently, the state variable of the compression device changes when the particle accumulator is compressed. Since detection takes place directly in the area of the particle accumulator, this can be implemented with greater accuracy than when determining the degree of loading based on a variable such as the textile properties or quantity of textile. Nevertheless, additional sensors that detect the degree of loading directly at the particle accumulator can be dispensed with, whereby the inventive method can be implemented with low expenditure.In principle, the method according to the invention can also be used to detect whether a particle storage device is actually being used. Furthermore, the method according to the invention can also detect a defect in the elastic element or a leak in the compression device.

[0013] According to the invention, the particle storage device is designed to be compressible, which is particularly implemented to expel liquid, and in particular water, from the particle storage device by compressing the particle storage device. For this purpose, the compression device is designed such that the particle storage device is accommodated between the elastic element and a surrounding housing of the compression device, and the elastic element can be expanded in a targeted manner to compress the particle storage device. As a result, the particle storage device is squeezed between the elastic element and the surrounding housing when the elastic element expands, thereby forcing the liquid out of the particle storage device.Since the particle loading of the particle storage device influences the volume occupied by the device, the state variable changes with the particle storage device's loading, allowing conclusions to be drawn about the particle storage device's loading level. The particle storage device is designed in a bag-like manner.

[0014] According to one embodiment of the invention, the expansion of the elastic element is determined as a state variable, with the degree of loading of the particle storage device subsequently being determined based on the expansion of the elastic element. The volume of the particle storage device is preferably determined from the expansion. This is because, given the known dimensions of the surrounding housing of the compression device and the determination of the expansion of the elastic element occurring during compression, the volume of the particle storage device achieved during compression can easily be determined. By comparing this with the volume of a completely empty particle storage device, a statement about the degree of loading is possible. This can be implemented advantageously and with little effort.

[0015] Particularly preferably, the expansion of the elastic element is detected using at least one strain gauge provided on the elastic element. This allows the expansion of the elastic element to be determined in a particularly reliable manner.

[0016] According to an alternative or possibly also supplementary embodiment of the invention, a force is determined as a state variable with which the elastic element acts on the particle accumulator during expansion and / or a relaxation of the elastic element following the expansion. The loading level of the particle accumulator is then determined based on each force. This also allows the loading level of the particle accumulator to be easily calculated from the respective force with which the elastic element in the compression device acts on the compressibly designed particle accumulator. Preferably, the respective spring constants / stiffnesses of the materials are taken into account.

[0017] In a further development of the aforementioned embodiment, each force is evaluated over a period of expansion and / or relaxation of the elastic element following the expansion. This makes it possible to determine when the elastic element is in contact with the particle storage device and exerts pressure on it, thereby determining the degree of loading of the particle storage device.

[0018] Preferably, each force is measured using at least one strain gauge provided between the elastic element and the particle accumulator and / or between the particle accumulator and the housing. This allows for reliable determination of the force, whereby a strain gauge can be provided between the elastic element and the particle accumulator, a strain gauge between the particle accumulator and the surrounding housing of the compression device, or both a strain gauge between the elastic element and the particle accumulator and a strain gauge between the particle accumulator and the surrounding housing.

[0019] When using at least one strain gauge, the respective strain gauge is then preferably evaluated in a bridge circuit, whereby a measurement of the respective state variable is easily possible with sufficient accuracy to determine the degree of loading.

[0020] In a further embodiment of the invention, the determined load level is compared with a limit value, wherein at least one measure is 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 storage device must be replaced or cleaned at least imminently.

[0021] The invention also relates to a control device for a household appliance, which is in particular a laundry treatment appliance. This control device is configured to determine the degree of loading of a compressible particle accumulator, which can be compressed in a compression device by expansion of an elastic element between the elastic element and a housing of the compression device. Furthermore, the control device is designed to determine the degree of loading based on at least one state variable of the compression device, which is dependent on a volume of the particle accumulator, and to determine the at least one state variable during the compression of the particle accumulator.Furthermore, the control unit can then be configured to implement one or more of the aforementioned variants of a method according to the invention for determining a loading level of a particle accumulator.

[0022] 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.

[0023] An advantageous embodiment of the invention, which is explained below, is illustrated in the drawings. It shows: Fig. 1 is a schematic view of a laundry treatment appliance; Fig. 2 a schematic representation of a compression device of a particle filter device of the laundry treatment appliance from Fig. 1; and Fig. 3 a flow diagram of a method for determining a loading level of a particle storage of the particle filter device of the laundry treatment appliance from Fig. 1, according to an embodiment of the invention.

[0024] Out of Fig. 1 shows a schematic view of a laundry treatment appliance 1, which can 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 in the laundry treatment appliance 1 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, a connection is established between the drum 3 and a dispensing tray 5 via the supply line 4, in which the 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 supplied to the drum 3 can be, in addition to water, also in particular washing liquor.

[0025] 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, whereby in particular microplastic particles and lint that have been introduced into the liquid during the laundry treatment are removed.

[0026] To store the separated particles, the particle filter device 7 is also equipped with a particle storage 9, which is designed to be compressible and also in Fig. 2 is indicated schematically. The particle storage 9 is arranged in a compression device 10, which is Fig. 2 and serves to compress the particle accumulator 9 in order to remove liquid from the particle accumulator 9 by specifically squeezing it out, thereby increasing the storage capacity of the particle accumulator 9 and obtaining a filter cake that is as dry as possible. Specifically, the particle accumulator 9 is accommodated in the compression device 10 between an elastic element 11 and a surrounding housing 12 of the compression device 10. The elastic element 11 can be expanded by means of compressed air, which is supplied for this purpose via a supply line 13, and subsequently presses the intermediate particle accumulator 9 against the surrounding housing 12. This then achieves the desired compression of the particle accumulator 9 and thus the squeezing out of liquid.

[0027] The operation of the laundry treatment appliance 1 is controlled by a Fig. 1, wherein the control unit 14 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 14 is then also able to determine a loading level of the particle storage 9 of the particle filter device 7 in order to inform an operator of the laundry treatment appliance 1 in good time about the need to clean or replace the particle storage 9. The control unit 14 can determine the loading level within the framework of a method according to the invention, the flow diagram of which is shown in Fig. 3 is shown.

[0028] The method according to the invention is initiated with the start of operation of the compression device 10 initiated to compress the particle accumulator 9. In a first step S1, at least one state variable is determined which, in the case of the compression device 10, is dependent on a volume of the particle accumulator 9.

[0029] According to a first conceivable variant of the method according to the invention, the state variable is an expansion experienced by the elastic element 11 at the end of the compression of the particle storage device 9. This expansion of the elastic element 11 can be measured in the compression device 10 via a strain gauge 15, which is attached to a surface of the elastic element 11 between the elastic element 11 and the particle storage device 9.

[0030] Alternatively or in addition to the aforementioned variant, in step S1, a force can also be used as a state variable of the compression device 10, which force is exerted on the particle accumulator 9 by the elastic element 11 during its expansion and / or during its relaxation following the expansion. In particular, the respective spring constants / stiffnesses of the materials are taken into account. This force can also be determined by incorporating measured values from the strain gauge 15 and / or with the aid of measured values from a strain gauge 16 placed between the particle accumulator 9 and the surrounding housing 12.The force determined in this way can also be evaluated over an actuation time of the elastic element 11 during its expansion and / or during its relaxation following the expansion in order to detect when the elastic element 11 in the compression device 10 rests against the particle storage device 9.

[0031] In both variants, the respective strain gauge 15 or 16 is evaluated in particular in a bridge circuit.

[0032] In a step S2 following step S1, the control unit 14 then evaluates the at least one state variable from step S1 and determines the loading level of the particulate accumulator 9, wherein this is done in particular approximately in the sense of an estimate. Following this, the loading level thus determined is then compared with a limit value in a further step S3. If this limit value is exceeded by the determined loading level, the process proceeds to step S4. Otherwise, the process proceeds to step S5, in which the method is initially terminated and is not initiated again until the next start-up of the compression device 10.

[0033] In step S4, however, the control unit 14 performs a measure by displaying a message on the laundry treatment appliance indicating the necessary cleaning or replacement of the particle storage device 9. Subsequently, the process is also initially terminated and only restarted the next time the compression device 10 is put into operation.

[0034] Within the scope of the invention, the at least one state variable of the compression device 10 can also be used to detect leaks in the supply line 13 and / or a defect in the elastic element 11 or to detect a lack of the particle storage device 9.

[0035] By means of the method according to the invention, a determination of the loading level of a particle storage device in a laundry treatment appliance can be realized with little effort and, at the same time, the loading level can be determined with high accuracy. 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 particle storage 10 Compression device 11 elastic element 12 housings 13 Supply line 14 Control unit 15 strain gauges 16 strain gauges S1 to S5 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 loading of a particle storage device (9) of a household appliance, preferably a laundry treatment appliance (1), wherein at least one variable is determined and the degree of loading of the particle storage device (9) is determined on the basis of the at least one variable, characterized by that a state variable of a compression device (10) is used as the variable, in which an elastic element (11) is expanded upon request for compression of the compressibly designed particle accumulator (9), whereupon the particle accumulator (9) is compressed between the elastic element (11) and a surrounding housing (12) of the compression device (10), and that each state variable is dependent on a volume of the particle accumulator (9) and is determined in the course of the compression of the particle accumulator (9). [2] Method according to claim 1, characterized bythat an expansion of the elastic element (11) is determined as a state variable, wherein the degree of loading of the particle accumulator (9) is subsequently determined on the basis of the expansion of the elastic element (11). [3] Method according to claim 2, characterized by that the extension of the elastic element (11) is detected via at least one strain gauge (15) provided on the elastic element (11). [4] Method according to one of the preceding claims, characterized by that a force is determined as a state variable with which the elastic element (11) acts on the particle accumulator (9) during the expansion and / or a relaxation of the elastic element (11) following the expansion, wherein the degree of loading of the particle accumulator (9) is subsequently determined on the basis of each force. [5] Method according to claim 4, characterized bythat each force is evaluated over a period of expansion and / or relaxation of the elastic element (11) following the expansion. [6] Method according to claim 4 or 5, characterized by that each force is measured by means of at least one strain gauge (15, 16) provided between the elastic element (11) and the particle accumulator (9) and / or between the particle accumulator (9) and the housing (12). [7] Method according to claim 3 and / or 6, characterized by that the at least one strain gauge (15, 16) is evaluated in a bridge circuit. [8] Method according to one of the preceding claims, characterized by that the determined load level is compared with a limit value, whereby at least one measure is initiated if the limit value 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 (14) for a household appliance, in particular for a laundry treatment appliance (1), wherein the control device (14) is designed to determine a degree of loading of a compressible particle accumulator (9) which is compressible in a compression device (10) by expansion of an elastic element (11) between the elastic element (11) and a housing (12) of the compression device (10), wherein the control device (14) is designed to determine the degree of loading on the basis of at least one state variable which is in each case dependent on a volume of the particle accumulator (9), and to determine the at least one state variable in each case during the compression of the particle accumulator (9). [11] Control device (14) 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 (14) 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 loading of the particle accumulator (9) 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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