Filter unit, process and tumble dryer with filter unit

Abstract

The invention relates to a filter unit (130) for filtering lint (305) from process air (300) of a clothes dryer (100), wherein the filter unit (130) comprises at least one filter element (200) for filtering lint (305) from conveyed process air (300), a collection container (310) which is arranged on the filter element (200) such that lint (305) filtered out by the filter element (200) is directed into the collection container (310), and a sensor unit (320a) which is shaped to detect a fill level of lint (305) in the collection container (310) and to output a corresponding fill level collection signal.

Description

[0001] The invention relates to a filter unit for a clothes dryer, a method for operating the filter unit and a clothes dryer with a filter unit.

[0002] WO 2024123479 A1 describes a tumble dryer with an externally mounted filter unit. Centrifugal separators can also be used in vacuum cleaners, sand traps in the automotive sector (for example, in the engine air filter area of ​​off-road vehicles), or as centrifugal separators in large industrial plants.

[0003] The approach presented here aims to create an improved filter unit for a clothes dryer, an improved method for operating the filter unit, and an improved clothes dryer with a filter unit according to the main claims.

[0004] According to the invention, this problem is solved by a filter unit for a clothes dryer, a method for operating the filter unit, and a clothes dryer with a filter unit having the features of the main claims. Advantageous embodiments and further developments of the invention are described in the following dependent claims.

[0005] The advantages achievable with the invention consist of non-contact sensing of lint and a resulting increased service life of the filter unit.

[0006] A filter unit for filtering lint from the process air of a clothes dryer is presented, wherein the filter unit comprises at least one filter element for filtering lint from conveyed process air, a collection container arranged on the filter element in such a way that lint filtered out by the filter element is directed into the collection container, and a sensor unit designed to detect the level of lint in the collection container and to output a corresponding level collection signal.

[0007] The filter unit can be designed to filter textile lint, dust particles, or similar substances from air or process air. The filter unit can be made of plastic or metal, for example. Alternatively, it can be made from a combination of plastic and metal components. The tumble dryer can be a heat pump dryer or a vented dryer. The filter element can be a centrifugal separator that removes lint from the airflow. The collection container can be designed to collect lint and prevent it from re-entering the tumble dryer's airflow. By detecting the amount of lint and receiving a fill level indicator, the user can always see how full the collection container is without having to open it. This increases user convenience.This also reduces the user's contact with lint. This, in turn, can improve occupational safety and the user's health.

[0008] In one embodiment, the sensor unit can be configured to determine the lint level using a transmission signal projected onto the surface of the lint collected in the collection container. This transmission signal can be, for example, a sound or acoustic signal and / or a light signal. This allows for simple and reliable non-contact sensing of the fill level in the centrifugal separator's collection container from the container's ceiling. The approach presented here enables sensing of the actual fill level regardless of the number of running programs. Thus, the user is always informed of the collection container's fill level and when it needs to be emptied.

[0009] According to one embodiment, the transmission signal can be an ultrasonic signal or a light signal. The sensor unit can, for example, be designed as a light source coupled with a camera or photosensor, or as a loudspeaker coupled with a microphone. This allows for the use of existing embodiments for corresponding sensor units, thus reducing manufacturing costs.

[0010] According to one embodiment, the sensor unit can be configured to determine the fill level using a received signal, which is received in response to the transmitted signal after a predetermined time and / or from a predetermined position. With these two embodiments, for example, a specific level or a total quantity of lint can be monitored. This allows the sensor unit to detect with particular accuracy when the collection container is full. Consequently, the collection container only needs to be emptied when it is actually full. Overall, this can result in less maintenance, as unnecessary emptying is avoided.

[0011] According to one embodiment, the sensor unit can have at least one light barrier, in particular wherein the light barrier is arranged such that a light beam of the light barrier is interrupted by lint from a certain fill level. The light barrier can, for example, run diagonally through or be aligned with the collection container. Alternatively, the light barrier can also run parallel to or be aligned with the bottom of the collection container. Thus, regardless of the shape of the collection container, it is possible to determine when it is full.

[0012] The sensor unit can, for example, be arranged inside the collection container according to one embodiment. Alternatively, the sensor unit can also be arranged outside the collection container and only look into it. The sensor unit enables contactless sensing, meaning there are no additional moving parts in the dryer that could easily break down. This also eliminates mechanical wear of such moving parts, making the dryer more maintenance-free than others.

[0013] According to one embodiment, the filter unit can include a warning device designed to emit a warning signal when the lint level in the collection container exceeds a predefined threshold. The warning device can, for example, include a light source. Alternatively or additionally, the warning device can also include a screen or a speaker. A user can thus receive a notification when the collection container really needs emptying. This reduces unnecessary cleaning and wear and tear on the components.

[0014] According to one embodiment, the filter element can be designed as a centrifugal separator. A centrifugal separator can be advantageous, for example, because it can be easily removed and replaced in case of a defect. At the same time, such a centrifugal separator can reliably separate particles or lint from the process air stream.

[0015] Furthermore, according to one embodiment, a method for operating the filter unit is presented, wherein the method includes a step of detecting the lint level in the collection container. By evaluating the actual amount of lint, the user can be provided with potential information and further insights into their laundry load. For example, this can indicate the quality of the cleaning and point to problems in the washing process that may lead to increased lint formation. Increased lint formation can, for example, be caused by a damaged tumble dryer or washing machine, which the user can then quickly counteract.

[0016] The approach presented here further creates a control unit designed to perform, control, or implement the step of a variant of the method presented here in at least one corresponding device. This embodiment of the invention in the form of a control unit also allows the problem underlying the invention to be solved quickly and efficiently.

[0017] The control unit can be configured to read input signals and use these input signals to determine and provide output signals. An input signal can, for example, be a sensor signal readable via an input interface of the control unit. An output signal can be a control signal or a data signal that can be provided at an output interface of the control unit. The control unit can be configured to determine the output signals using a processing instruction implemented in hardware or software. For example, the control unit can include a logic circuit, an integrated circuit, or a software module and may be implemented as a discrete component or comprised of a discrete component.

[0018] A computer program product or computer program with program code that can be stored on a machine-readable medium such as semiconductor memory, hard disk memory, or optical memory is also advantageous. If the program product or program is executed on a computer or control unit, it can be used to carry out, implement, and / or control the steps of the method according to one of the embodiments described herein.

[0019] Furthermore, according to one embodiment, a clothes dryer is presented, comprising a drum for holding laundry and a fan unit for extracting process air from the drum. The clothes dryer also includes a variant of a filter unit presented herein, arranged between the drum and the fan unit, and / or a variant of a control unit presented herein. This avoids unnecessary dryer downtime for cleaning or maintenance. Reduced dryer downtime can, for example, lead to higher equipment availability and lower service costs.

[0020] According to one embodiment, the tumble dryer can include a user interface element designed to display the fill level of the collection container. The user interface element can also be designed to provide information about emptying the collection container when it is full. This avoids unnecessary emptying of the collection container.

[0021] Although the described approach is based on a household appliance, the approach described here can be used accordingly in connection with a commercial or professional device, for example a medical device, such as a cleaning or disinfection device, a small sterilizer, a large-capacity disinfector or a container washing system.

[0022] An embodiment of the invention is shown purely schematically in the drawings and is described in more detail below. It shows Fig. 1 a schematic representation of an exemplary embodiment of a clothes dryer; Fig. 2 a perspective sectional view of an exemplary embodiment of a clothes dryer; Fig. 3 a sectional view of an exemplary embodiment of a clothes dryer; Fig. 4 a schematic representation of a procedure for operating the sensor unit; Fig. 5 a perspective view of an embodiment of a filter unit of the tumble dryer; Fig. 6. A further schematic representation of a procedure for operating the sensor unit; and Fig. 7 a flowchart of an exemplary embodiment of a method for operating a filter unit.

[0023] Fig. Figure 1 shows a schematic representation of an embodiment of a clothes dryer 100. The clothes dryer 100 can be designed as a household appliance or as a commercial appliance. Like conventional clothes dryers, the clothes dryer 100 has a drum 110 for holding textiles. A flow of process air is passed through the drum 110, drying the textiles inside. The process air in the clothes dryer 100 is conveyed by a fan unit 120. A filter unit 130 is arranged between the fan unit 120 and the drum 110. The filter unit 130 is designed to filter or separate lint, fluff, particles, or similar substances from the process air. For this purpose, the filter unit 130 includes, for example, a centrifugal separator.Furthermore, the tumble dryer 100 includes a control unit 140, which is intended to dry textiles in the tumble dryer 100 by controlling the fan unit 140 to convey process air from the drum 110 through the filter unit 130.

[0024] The tumble dryer 100 includes an opening 150 through which fresh air is drawn in. This fresh air is then heated by a heating element 160. The heated air is directed into the drum 110, where it dries wet textiles. Subsequently, the process air is drawn through the filter unit 130 by the fan unit 120. The filter unit 130 is located, for example, in a lint chamber 170. After passing through the filter unit 130, the filtered air can either be discharged from the tumble dryer 100 through an outlet 180 or reused for another drying cycle.

[0025] The filter unit 130 comprises at least one filter element for filtering lint from conveyed process air. The lint is then collected in a collection container, which is positioned on the filter element in such a way that lint filtered out by the filter element is directed into the collection container. The filter unit 130 also has a sensor unit designed to detect the lint level in the collection container and output a level-of-collection signal.

[0026] Furthermore, according to this embodiment, the tumble dryer 100 has a user interface element 190 designed to display the fill level of the collection container. The user interface element 190 can output information about emptying the collection container when the container is full or is detected as full.

[0027] Fig. Figure 2 shows a perspective sectional view through part of an exemplary embodiment of a clothes dryer 100. The clothes dryer 100 is as described in Fig. The described tumble dryer is formed. The tumble dryer 100 comprises the filter unit 130 with a filter element 200 in the lint chamber 170, and the fan unit 120.

[0028] Filter element 200, for example, is designed as a centrifugal separator. Six filter elements 200 are arranged side by side. The use of centrifugal separators or cyclone filters in the tumble dryer 100 makes it possible to separate lint without the use of a fabric filter. The centrifugal separator separates the lint and foreign particles at a point defined by its geometry. This makes it possible to collect the lint in a specific volume. Unlike fabric filters, which become clogged with each drying cycle (thus allowing the formation of a so-called lint carpet), here the lint falls loosely into a designated space. With a fabric filter, the degree of lint adhesion to the fabric filter can be determined by measuring the pressure difference. The more lint clogs the fabric filter, the higher the pressure difference between the two sides of the lint filter.However, if there is a very high pressure difference, i.e., if the lint filter is highly clogged, there may no longer be a sufficient flow of process air, so the lint filter then has to be mechanically cleaned, which is complex and may damage the lint filter.

[0029] During the drying process, the process air is drawn from the drum 110 by the fan unit 120. It is then passed through the lint chamber 170, where it is cleaned of the lint present in the process air. The method of lint separation is of secondary importance; however, according to one variant presented here, all the lint should be collected in a container. This can be achieved, for example, using a centrifugal separator. In this example, centrifugal separators mounted in parallel are used to filter the lint from the process air. Fig. Figure 2 shows six centrifugal separators as filter elements 200 in parallel as an example. The separated lint falls out of the centrifugal separator through a discharge opening and thus enters the collection container.

[0030] Unlike a fabric filter, a centrifugal separator does not clog the filter element. The centrifugal separator does not become clogged over time. The separated lint falls into the collection container, filling its volume with each cycle. If the amount of lint exceeds a certain fill level, the centrifugal separator cannot remove all foreign particles or lint from the process air, and the lint accumulating at the discharge opening can be drawn back into the separator. Since effective lint separation is no longer guaranteed under these circumstances, the lint may be drawn in by the fan unit 120 and either into the exhaust duct or (in tumble dryers with a recirculating air component, e.g., heat pump dryers) reintroduced into the drying process. For example, this can lead to...Exhaust ducts, heat exchangers or heating coils can become contaminated with lint, which greatly reduces the performance of the 100 tumble dryer and in the worst case can even lead to a tumble dryer fire.

[0031] Fig. Figure 3 shows a sectional view of an exemplary embodiment of a clothes dryer 100. The clothes dryer 100 is, for example, like the one in Fig. 1 or Fig. Figure 2 describes a clothes dryer. Process air 300 is directed from the drum 110 into the lint chamber 170. More precisely, the process air 300 is directed into the filter element 200, which directs the process air 300 tangentially to the previous flow direction. The filter unit 130 is designed to filter out lint 305 and other substances or particles different from lint 305 from the process air 300. The clothes dryer 100 also includes a collection container 310 and a sensor unit 320, which, for example, comprises a transmitter unit 320a for emitting an acoustic or optical signal and a receiver unit 320b for receiving an acoustic or optical signal.

[0032] The collection container 310 is a section located within the lint chamber 170, in which lint 305 is collected once it has been filtered from the air. The lint 305 is first passed through the filter element 200 and then directed into the collection container 310. The collection container 310 is, for example, located below the filter element 200, so that the lint 305 simply falls directly from the filter element 200 into the collection container 310. The lint 305 then accumulates in the collection container 310. To measure how many lint particles 305 are in the collection container 310, the filter unit 130 has the sensor unit 320a. The sensor unit 320a is, for example, located on the ceiling of the collection container 310. The sensor unit 320 sends out a transmission signal 330 via a transmitter unit 320a, which hits the fluff 305 on the bottom of the collection container 310.In this embodiment, the transmitted signal 330 is an ultrasonic signal. When the transmitted signal 330 encounters lint 305, it is reflected as a received signal 340, which is reflected back to the receiving unit 320b of the sensor unit 320. If the received signal 340 is detected or acquired by the receiving unit 320b before a predetermined time, the fill level can be determined using the received signal 340. The predetermined time corresponds to the minimum time the received signal 340 may take to travel from the transmitting unit 320a through an unobstructed area over the lint, be reflected off the surface of the lint in the collection container 310, and return to the receiving unit 320b when the collection container 310 is nearly full.If the predetermined (running) time is undershot by the received signal 340, it can be assumed that the level of lint in the collection container 310 is too high, so that the runtime of the received signal 340 is too short.

[0033] If a predetermined level or threshold is exceeded, i.e., in this case, if the received signal 340 is detected very quickly, a warning signal 350 is output by the filter unit 130, for example, according to one embodiment. For this purpose, the filter unit 130 includes a warning device 360. The warning device 360 ​​outputs the warning signal 350, for example, as a sound. Alternatively, the warning device 360 ​​can also output a visual stimulus, such as a lamp illuminating. This visual stimulus can, for example, also be provided or output via the user interface element 190. The non-contact sensing of the lint 305 can thus be carried out in various ways. These are largely independent of the design of the centrifugal separator or the geometry of the collection container 310.

[0034] In the sensing principle presented here, the sensor unit 320a emits the transmission signal 330 (for example, as an ultrasonic signal). Alternatively, the sensor unit 320a can be a time-of-flight sensor or a corresponding PDC (park distance control) sensor, such as those that can be installed in the rear of vehicles.

[0035] When the transmission signal 330 emitted by the transmitter unit 320a encounters a surface, in this case the lint mat, it is reflected. A receiver located next to the transmitter receives the reflected receiver signal 340, with the transmitter and receiver potentially being housed in the same unit. The transit time t of the reflected receiver signal 340 is used to determine the air path the signal has traveled. As the lint mat thickens, the free air path decreases, thus shortening the transit time t. When the receiver signal 340 reaches a certain level, a corresponding message can be displayed to the operator of the tumble dryer 100 (e.g., via text on the display or an indicator light). The advantage of this type of detection is that the fill level in the collection container 310 can be continuously monitored.This means that different threshold values ​​can be output with just one sensor unit as a transmitter-receiver pair, regardless of the program running in the tumble dryer or the textiles being treated.

[0036] Fig. Figure 4 shows a schematic representation of a procedure 400 for operating the sensor unit. The procedure 400 describes an embodiment of the in Fig. 3 described sensor unit 320a which emits a transmission signal 330 in the form of an ultrasonic signal.

[0037] A query signal 410 is sent to the sensor unit 320a to measure the fill level in the collection container 310. The sensor unit 320a then sends the transmit signal 330, for example, in the form of an ultrasonic signal. The transmit signal 330 requires a period of time T to arrive as a received signal at the receiving unit 320b. If the period T is a predetermined time T SIf the value matches (or is greater than) the specified value, the collection container is not yet full and the transmission signal 330 continues to be sent. If the time period T is less than the predetermined time T, the transmission signal will continue to be sent. S If this is the case, an output signal 420 is sent, which signals that the collection container is full or filled above the corresponding fill level and must / should be emptied.

[0038] Fig. Figure 5 shows a perspective view of an embodiment of another filter unit 130 in the tumble dryer 100. The filter unit 130 also has six filter elements 200 in the lint chamber 170, and the collection container 310 with the sensor unit 320, which includes the transmitter unit 320a and the receiver unit 320b.

[0039] Here, the transmitter unit 320a is arranged separately from the receiver unit 320b. The sensor unit 320a and the receiver unit 320b are located on opposite sides of the collection container 310. The sensor unit 320a emits the transmission signal 330 in the form of a light beam. This creates a light barrier 500 between the sensor unit 320a and the receiver unit 320b.

[0040] In this variant of the lint detection system, the light barrier 500 is installed in the area of ​​the collection container 310. The position of the light barrier 500 depends primarily on the geometry of the collection container 310 and the lint level to be triggered. The light barrier 500 also consists of a transmitter and a receiver. The transmitter, or transmitting unit 320a, emits light (for example, in the visible or invisible spectrum, e.g., infrared). As long as the light beam reaches the receiver, the light barrier 500 is closed (similar to a mechanical switch). If the light beam is interrupted by a thick, persistent layer of lint, the light barrier 500 opens and a corresponding message is sent to the operator. This message can also appear as text or a pictogram on a display or be emitted as an acoustic signal. Output in the form of, for example, a warning light would also be possible.It is important to note that for each 500 light barrier sensor unit (320), only one transmitter-receiver pair can be monitored.

[0041] Fig. Figure 6 shows a further schematic representation of a procedure 600 for operating the sensor unit 320. The procedure 600 describes an exemplary embodiment for the one described in Fig. 5 described sensor unit 320a, which is designed as a light barrier 500 with a transmitter unit 320a and a receiver unit 320b.

[0042] A query signal 610 is sent to the transmitter 320a. Transmitter 320a then sends a light signal 615 to receiver 320b. When the light signal 615 arrives at receiver 320b, the light barrier is activated. This indicates that the collection container is not yet full, or is filled to or above the specified fill level. If the light signal 615 is not registered by receiver 320b, an output signal 620 is sent, indicating that the collection container must / should be emptied.

[0043] Fig. Figure 7 shows a flowchart of an embodiment of a method 700 for operating a filter unit. The method 700 for operating the filter unit has a step 701 of detecting the fill level of lint in the collection container.

[0044] The approach presented here is advantageous compared to previous methods, in which lint and other foreign matter are mechanically removed from the airflow by lint filters, because it eliminates the need to wait for a continuous deterioration in filtration performance before filter cleaning becomes necessary. Furthermore, this approach does not use partially multi-stage mechanical filters, which essentially consist of a series of filters with different mesh sizes. Cleaning such filters would, in most cases, have to be done manually, for example, with a broom. In these systems, filter contamination is determined by a differential pressure. As the filter contamination increases, the airflow through the filter decreases. Consequently, the pressure difference between the two sides of the filter increases.In household appliances, condenser dryers use an "intelligent cleaning system" which flushes lint from the lint filter into a reservoir using water. This occurs after or during the drying program. Therefore, while no sensing is required, a clogged heat exchanger would still only be detectable via differential pressure measurement.

[0045] Differential pressure measurements used in lint filters are physically inapplicable and unnecessary for centrifugal separators, as these do not become clogged. A simple counter in the control unit could inform the operator that the collection container needs emptying. However, this would not always or necessarily correspond to the actual amount of lint in the collection container, depending on the different programs the dryer can run or the drying processes in the drum. Especially in commercial settings, the dryer's downtime is crucial, as no further laundry can be dried during this period. A counter would need to be designed so that, in a worst-case scenario (laundry with a high lint load), no lint is drawn back into the system. This would provide a high level of safety. However, this would require emptying the collection container more frequently than is actually necessary in most cases (e.g., when...(This would result in more laundry being dried with less lint). This would increase the operating costs of such a tumble dryer and would be economically unfavorable. However, the approach presented here allows for a significantly simpler and more economical operation of a tumble dryer. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] WO 2024123479 A1

[0002]

Claims

[1] Filter unit (130) for filtering lint (305) from process air (300) of a clothes dryer (100), wherein the filter unit (130) comprises the following features: at least one filter element (200) for filtering lint (305) from conveyed process air (300); a collection container (310) arranged on the filter element (200) such that lint (305) filtered out by the filter element (200) is directed into the collection container (310); and a sensor unit (320a) designed to detect the level of lint (305) in the collection container (310) and to output a corresponding level collection signal. [2] Filter unit (130) according to claim 1, wherein the sensor unit (320a) is configured to determine the fill level of lint (305) using a transmit signal (330) which is directed onto a surface of the lint (305) collected in the collection container (310). [3] Filter unit (130) according to claim 2, wherein an ultrasonic signal and / or a light signal is used as the transmitting signal (330). [4] Filter unit (130) according to claim 3, wherein the sensor unit (320a) is configured to determine the fill level using a received signal (340) which is received in response to the transmitted signal (330) after a predetermined time and / or from a predetermined position. [5] Filter unit (130) according to one of the preceding claims, wherein the sensor unit (320a) has at least one light barrier (500), in particular wherein the light barrier (500) is arranged such that a light beam of the light barrier (500) is interrupted by lint (305) from a certain fill level. [6] Filter unit (130) according to one of the preceding claims, wherein the sensor unit (320a) is arranged in the collection container (310). [7] Filter unit (130) according to one of the preceding claims, wherein the filter unit (130) has a warning device (360) configured to issue a warning signal (350) when the fill level of the lint (305) in the collection container (310) exceeds a predefined threshold. [8] Filter unit (130) according to one of the preceding claims, wherein the filter element (200) is designed as a centrifugal separator. [9] Method (700) for operating the filter unit (130) according to claims 1 to 8, wherein the method (700) comprises a step (701) of detecting the fill level of lint (305) in the collection container (310). [10] Control unit (140) configured to perform and / or control the step (701) of the method (700) according to claim 9 in a corresponding unit. [11] Computer program product with program code for carrying out the method (700) according to claim 9, when the computer program product is executed on a control unit (140) according to claim 10. [12] Clothes dryer (100) with a drum (110) for receiving laundry and a fan unit (120) for conveying process air (300) from the drum (110), wherein the clothes dryer (100) further comprises a filter unit (130) according to claims 1 to 8, which is arranged between the drum (110) and the fan unit (120), and / or wherein the clothes dryer (100) comprises a control unit (140) according to claim 10. [13] Clothes dryer (100) according to claim 12, comprising an operator interface element (190) configured to display the fill level of the collection container (310), and / or wherein the operator interface element (190) is configured to output information to empty the collection container (310) when the collection container (310) is full.

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