Filter element, filter system, laundry dryer and method

Abstract

Filter element (10) for a clothes dryer (11) which is designed to be arranged in an air path (L) wherein the air path (L) is designed to guide a process air flow (PL) wherein the filter element (10) comprises a mechanism (M) which is designed to allow the filter element (10) to be transferred into a filter position (FP) and into an open position (OP).

Description

[0001] The present invention relates to a filter element, a filter system with such a filter element, a clothes dryer with such a filter system and a method for operating such a filter system.

[0002] Filters for tumble dryers are known from the prior art. Such filters are designed to remove particles, especially lint or fluff, from an airflow or process stream. It is known that the airflow is directed to an evaporator. There, the water absorbed by the air in the airflow condenses. The air is then heated at the condenser to increase its moisture absorption capacity. In the next step, the air flows through the process chamber. The cycle then repeats. The filter is typically located after the process chamber. However, maintaining a consistent airflow requires significant energy. This negatively impacts the energy efficiency and performance of the tumble dryer. This airflow cycle is energy-intensive because the airflow volume must be kept essentially constant for efficient operation of the tumble dryer.

[0003] This has revealed a need to provide a way to improve the efficiency or performance of a tumble dryer.

[0004] The object of the present invention is therefore to provide a filter element. Furthermore, it is an object of the present invention to provide a filter system, a clothes dryer, and a method.

[0005] The problem is solved by the filter element with the features of claim 1. The problem is further solved by the filter system with the features of claim 8, by the clothes dryer with the features of claim 9, and by the method with the features of claim 10.

[0006] A first aspect of the present invention relates to a filter element for a clothes dryer, which is designed to be arranged in an air path, wherein the air path is designed to guide a process airflow, and wherein the filter element comprises a mechanism designed to allow the filter element to be moved into a filter position and into an open position.

[0007] The filter element can comprise a structure or material designed or suitable for filtering particles from a process air stream. In particular, the filter element can have a structure or composition that is at least partially porous and / or air-permeable, enabling the filtering of particles, especially lint or fluff, from the process air stream.

[0008] The process airflow is an airflow that is guided through the air path into a process chamber, for example, a dryer drum. During operation, the airflow is directed through the process chamber to absorb water or moisture. The airflow can be generated, in particular, by a fan or blower. The airflow is guided through the air path. This means that the air path defines the course of the airflow. The air path preferably forms a flow channel for the airflow, at least in sections. The air path can form a closed loop.

[0009] The tumble dryer can also be designed as a fully automatic dryer. Furthermore, the tumble dryer can be designed as a heat pump dryer or a condenser dryer.

[0010] The mechanism serves to move the filter element into the filter position and into the open position. Specifically, the filter element can be moved from the filter position to the open position and vice versa. The mechanism can be designed to allow a rotary, pivoting, and / or linear movement. For example, the filter element can be rotatable about a central axis and moved into the open and filter positions by a rotary motion. Alternatively, the filter element can be pivotable about an axis, allowing it to be folded into the open and filter positions. Another example is that the filter element can be displaced along an axis, allowing it to be moved into the open and filter positions by a linear movement. A combination of these examples is also possible.The mechanism can be activated automatically and / or manually.

[0011] In the filter position, the filter element is completely positioned within the air path, so that the process airflow passes through the filter element, and in particular, the entire process airflow passes through the filter element. In other words, in the filter position, the filter element completely encloses the air path. In the open position, the filter element is positioned in the air path such that the process airflow at least partially bypasses the filter element. In particular, in the open position, one of the filtering properties of the filter element is at least partially reduced compared to the filter position.

[0012] Compared to the prior art, the filter element according to the invention enables the process airflow to be filtered preferably only when the particle or lint load is particularly high. This can mean that the number of particles in the airflow is particularly high or reaches a defined limit. If a filter element is arranged in an air path during operation, the pressure in the process airflow drops. This means that more energy must be expended to maintain a desired pressure.

[0013] In one embodiment, the filter element comprises a sieve, a foam, and / or a textile. Different filter materials allow for various porous or permeable structures and thus different filter properties. This enables the filtering of particles, especially lint of varying sizes, from the process airflow. In particular, this allows for the implementation of multiple filter stages. Sieves can be easily removed and cleaned, simplifying maintenance. Furthermore, sieves are robust and resistant to mechanical stress. They are well-suited for effectively retaining larger lint and particles. Additionally, a sieve filter results in lower pressure drop, allowing for good air circulation of the process airflow. This improves the dryer's energy consumption. A foam filter exhibits a high filtration capacity.Foam filters offer a large filter surface area, enabling effective retention of small particles and lint while maintaining relatively good air permeability. Furthermore, foam filters are lightweight and flexible and can be used in various shapes to adapt to the dryer's design. Textile filters can retain very fine particles. They can be washable and therefore reusable. Textile filters are available in various materials and weaves to meet specific requirements. The choice of filter depends on the specific requirements of the tumble dryer and the desired filter properties.

[0014] In one embodiment, the filter element has a wedge-shaped geometry. In other words, the filter element can have a V-shaped or W-shaped cross-section. One advantage of a wedge-shaped filter element in the dryer is that it offers a larger filter surface area. The wedge shape allows the airflow to pass through the filter element more efficiently, while simultaneously capturing more dust, lint, and dirt particles. This results in better air circulation and more effective drying because air resistance is reduced and the dryer operates more efficiently. Furthermore, the larger filter area means that the filter element needs to be cleaned or replaced less frequently.

[0015] In one embodiment, the filter element mechanism includes an actuator and / or is mechanically coupled to an actuator to move the filter element from the filter position to the open position and / or vice versa. More precisely, the actuator can be configured to move the filter element from the filter position to the open position and / or from the open position to the filter position. The filter element may be subjected to a restoring force. This restoring force can be provided, for example, by a spring element connected to the filter element. In this way, the actuator can move the filter element only to the filter position or only to the open position. For example, the actuator can be an electric actuator. Alternatively, other types of actuators are conceivable. For example, a shape memory wire can be used to actuate the filter element.can be used to move the filter element into the open position or into the filter position.

[0016] In one embodiment, the filter element includes a handle. This allows the handle to be removed by hand. In particular, this makes it easier to remove the filter element, for example for maintenance or cleaning. The handle can also be used, alternatively or additionally, to activate and / or deactivate the mechanism.

[0017] In one embodiment, the filter element includes an allergy filter, in particular a pollen filter. An allergy filter has the advantage of effectively trapping fine particles such as dust, pollen, and mite allergens. This reduces the allergen load in the air and ensures that the dried laundry is cleaner and more hypoallergenic, which is particularly beneficial for people with allergies and / or sensitive skin.

[0018] Another aspect of the present invention relates to a filter system for a clothes dryer, comprising: at least one filter element according to one of the preceding embodiments, wherein the filter system comprises an actuator coupled to a mechanism of the filter element to move the filter element into a filter position and into an open position, wherein the filter system comprises a control unit to control the actuator depending on at least one system piece of information.

[0019] The filter system is designed for use in a tumble dryer. Preferably, the filter system comprises at least two or at least three filter elements. The filter elements are preferably arranged in series in the air path. This means that the filter elements are arranged in a row in the air path.

[0020] The actuator is preferably designed to automatically move the filter element into the filter position and / or the open position. In particular, the actuator can be an electric servo motor. One advantage of using an actuator to operate the filter element is its automated control. The actuator enables precise and time-controlled adjustment of the filter without the need for manual intervention. This ensures consistent performance and increased efficiency, especially in filter systems that must operate continuously. Automated operation also increases operational reliability and reduces maintenance requirements.

[0021] The control unit is designed to control the actuator. It is possible that the control unit is a microprocessor-controlled unit. This uses a microprocessor to precisely monitor and adjust at least one system information. Alternatively, it is conceivable that the control unit is a fuzzy logic control unit. The fuzzy logic control unit is characterized by intelligent decision-making, adaptability, and user-friendliness. First, the fuzzy logic gathers various system information relevant to the operation of the clothes dryer. The fuzzy logic control unit makes decisions based on fuzzy rules, which can, for example, be formulated in natural language. This allows the fuzzy logic control unit to consider transition ranges, enabling more flexible decisions.This allows a tumble dryer to better decide how long a drying process needs to continue when using a fuzzy logic control unit, even if the moisture content of the laundry cannot be measured exactly.

[0022] The term "at least one piece of system information" refers to information that affects the operation of a clothes dryer. For example, at least one piece of system information may include humidity information, temperature information, torque information, pressure information, flow rate information, and / or filter information.

[0023] In one embodiment, the filter system includes a humidity sensor to detect humidity levels. Several methods are possible for measuring humidity. One option is to use capacitive or resistive sensors. Capacitive sensors measure humidity by monitoring the change in capacitance (electrical storage) between two electrodes. When the laundry contains moisture, the capacitance changes, and the humidity in the laundry can be determined. Resistive sensors measure the resistance of the laundry. When the laundry is damp, it has a lower resistance, which changes as the laundry dries. Temperature-based humidity measurement measures the air temperature inside the dryer.If the air temperature doesn't rise further during the drying process, it can be assumed that the laundry is mostly dry, since the evaporation of moisture consumes energy (heat). Humidity can also be determined using a humidity sensor or hygrometer. The hygrometer measures the relative humidity inside the dryer. If the laundry still contains moisture, the humidity inside the dryer will be higher because water is evaporating. If the humidity inside the dryer decreases, this indicates that the laundry is drying. Furthermore, moisture measurement is possible using infrared (IR) technology. Infrared radiation is directed at the laundry, and the absorption of this radiation changes with the moisture content. Depending on how much infrared light is absorbed by the laundry, the dryer can accurately determine the moisture level.Another option is indirect moisture measurement, for example, through drum movement. When laundry is still damp, it weighs more and offers greater resistance to movement. The dryer can monitor this change in resistance. Condensation or evaporation moisture measurement is based on monitoring the amount of condensate (water that forms after evaporation from the laundry). The amount of condensed water indicates how much moisture remains in the laundry and can help optimize the drying process. Alternatively, it is possible to use a combination of the methods mentioned above. For example, dryers can be used in conjunction with temperature and / or humidity sensors. This allows for more accurate and reliable moisture information.

[0024] In one embodiment, the filter system includes a temperature sensor to acquire temperature information. Various methods can be used for temperature sensing. For example, air temperature sensors (e.g., NTC or PTC) are possible. Thermistors are temperature-dependent resistors that change their electrical resistance with temperature. In dryers, these can be used to measure the temperature of the air or the laundry. Infrared temperature sensors can also be used. These measure the infrared radiation (heat radiation) emitted by the laundry or the air in the dryer. This radiation provides information about the surface temperature of the material. This allows for non-contact measurement, resulting in a less invasive and faster temperature measurement. Another possibility is to use a thermocouple to measure temperature.A thermocouple consists of two wires made of different metals, joined at one end. When this end is heated, a small voltage is generated, which correlates with the temperature. This voltage can then be measured and converted into temperature.

[0025] In one embodiment, the filter system includes a torque sensor to acquire torque information. For example, the torque of the dryer drum can change as the drying process progresses, since the moisture content and thus the weight of the laundry decreases. This change in torque can indicate the degree of dryness of the laundry and therefore the prevailing lint load. Alternatively, the torque of a fan can be determined. When humidity is high, the air contains more water vapor, which has a lower density than dry air. Less dense air is easier for the fan to move, which can result in lower torque. At low humidity, the air is denser, and the fan must expend more energy to move the air, resulting in higher torque.

[0026] Airflow resistance: Higher humidity can also affect airflow resistance, especially if the drying process draws moisture from the textiles or other materials in the dryer. Humid air has a higher viscosity, which slows the airflow and may put more strain on the fan, resulting in higher torque.

[0027] Fan torque as an indicator: Measuring the fan's torque can provide clues about the humidity level. Higher torque could indicate lower humidity (denser, heavier airflow), while lower torque suggests higher humidity (lower density, lighter airflow).

[0028] In one embodiment, the filter system includes a flow sensor and / or a pressure sensor to acquire pressure and / or volumetric flow rate information. For example, differential pressure sensors, diaphragm pressure sensors, piezoelectric pressure sensors, and / or capacitive pressure sensors can be used. The lint load can be derived from the measured pressure and / or volumetric flow rate.

[0029] In one embodiment, the filter system includes an optical sensor to provide filter information. For example, a laser sensor can scan the filter element to measure the lint load. Alternatively or additionally, infrared sensors are possible.

[0030] When the filter system is installed in a clothes dryer, the sensors are preferably arranged downstream of the process chamber. The term "downstream" refers to the direction of the process airflow. Alternatively or additionally, it is conceivable to arrange one of the aforementioned sensors within the process chamber. For example, a conductivity sensor can be located in a circulator within the process chamber, particularly in a drum. The circulator serves to circulate the laundry when the process chamber or drum rotates.

[0031] In one embodiment, at least one piece of system information is stored in a database, particularly a local database or a cloud. The database is preferably connected to the control unit via signal transmission, enabling the control unit to compare measured system information with system information stored in the database. Alternatively or additionally, the database can provide the control unit with system information to control the filter system or its actuator. Alternatively or additionally, the filter system can be updated and continuously improved or adapted in this way.

[0032] InIn one embodiment, the filter element switches from the open position to the filter position at a humidity level between 8% and 12%. This allows the filter element to filter the process airflow even when there is a high lint load. For example, during the operation of a dryer, a particularly high number of particles, lint, or fluff is not present in the process airflow at all times. If the residual moisture content is >50% at the beginning of a drying process, the laundry in the dryer will be wet. For example, 5 kg of laundry can still contain 2.5 liters of water at 50% residual moisture. InIn this state of the laundry, no or only a small amount of particles or lint are picked up by the process airflow. This means that the filter element can be moved to the open position or remain in that position. Only at a moisture content of 8%–12% is the laundry considered iron-dry. This means that the laundry is sufficiently dry to be ironed. At this moisture level, the amount of lint picked up by the process airflow is sufficient to move the filter from the open position to the filter position. In particular, this can improve the performance, especially the efficiency, of a tumble dryer.

[0033] Another aspect of the present invention relates to a clothes dryer with a filter element according to one of the preceding embodiments and / or a filter system according to one of the preceding embodiments.

[0034] The tumble dryer preferably has at least two filter elements, and in particular three filter elements, wherein one filter element is arranged in the flow direction of a process air stream downstream of or within the feed opening or loading opening, one filter element is arranged directly upstream of a heat exchanger, and one filter element is arranged between the heat exchanger and the feed opening or loading opening. The filter elements are preferably arranged in series in the air path.

[0035] Another aspect of the present invention relates to a method for operating a filter system according to one of the preceding embodiments or a clothes dryer with such a filter system, comprising the following steps: capturing and / or providing at least one system information, transmitting the system information to a control unit, and moving at least one filter element into a filter position or into an open position based on the at least one system information.

[0036] It is possible for the method to be a computer-implemented method. This means that it is possible for the method to be provided by a computer program product. More precisely, the computer program product may include commands and / or instructions that cause the process steps according to the aforementioned method to be carried out in a filter system according to one of the embodiments mentioned above. Furthermore, it is possible to provide a computer-readable product and / or a data carrier on which the aforementioned computer program product is stored.

[0037] Furthermore, one aspect may specifically concern the use of an actuator with a filter element, particularly with a filter element mechanism. An actuator may, as described above, comprise an electric stepper motor or other suitable types of actuators.

[0038] Individual features and embodiments of the present invention can be combined with other features in other embodiments to form new embodiments. Advantages and further developments mentioned for the features or embodiments also apply analogously to the new embodiments. Further developments and advantages mentioned in connection with the apparatus also apply analogously to the method and vice versa.

[0039] The following is an exemplary description of the revelation with reference to the accompanying figures, which show Figure 1a: a schematic view of an embodiment of a filter element according to the invention in an open position; Figure 1b: a schematic view of the filter element according to Figure 1A in a filter position; Figure 2a a schematic view of an embodiment of a filter element according to the invention in an open position; Figure 2ba schematic view of the filter element according to Figure 1A in a filter position; Figure 3a a schematic view of an embodiment of a filter system according to the invention in the open position and in the filter position in a tumble dryer; and Figure 3b a section of the filter system according to Figure 3a .

[0040] In Figure 1a A filter element 10 is shown in an open position OP. Figure 1b The filter element 10 is according to Figure 1a The filter element 10 is shown in a sectional view. A process airflow PL flows through the filter element 10. The process airflow PL is represented by an arrow.

[0041] The filter element 10 has an inlet area 12 and an outlet area 13. The inlet area 12 has a substantially rectangular geometry. The outlet area 13 is arranged downstream of the process airflow PL in the direction of flow. The filter element 10, or rather the outlet area 13, has two filter sections 14. The filter sections 14 are designed to be porous, or air-permeable, at least in sections. This means that in the filter position, the process airflow can pass through the filter sections 14. The filter sections 14 can also be described as movable filter surfaces. The filter sections 14 are movably arranged on the inlet area 12. The free ends of the filter sections 14 are movable towards and away from each other. The filter element 10 has a mechanism (not shown) designed to move the filter sections 14 into the open position OP and into the filter position FP.The filter elements 14 are in . Figure 1a aligned parallel to each other. In Figure 1B The free ends of the filter elements 14 are in contact with each other. In other words, the filter elements 14 form a V-shaped or wedge-shaped geometry in a cross-section at filter position FP.

[0042] Figure 2A and Figure 2B show another possible embodiment of a filter element 10. Figure 2A The filter element 10 is in the open position and in Figure 2BFilter element 10 is arranged in filter position FP. Filter element 10 has an inlet area 12 and an outlet area 13. Filter element 10 comprises four filter elements 14. The filter elements 14 have a mechanism for moving them between the open position OP and filter position FP. Two of the filter elements 14 form a filter element pair. Each of the two filter element pairs is movably connected to the inlet area 12 and can be moved between an open position OP and a filter position FP. In the open position OP, the filter elements 14 are arranged essentially parallel to each other. In filter position FP, the filter element pairs each form a V-shaped or wedge-shaped geometry. The filter element pairs are arranged side by side. This means that the filter elements are adjacent to each other. Together, the filter element pairs thus form an essentially W-shaped geometry in cross-section.

[0043] Figure 3a shows a tumble dryer 15 with a filter system 11. Figure 3b shows a section of the tumble dryer 15 according to Figure 3a The tumble dryer 15 has three filter elements, number 10. In Figure 3a The filter elements 10 are arranged in the open position OP and in Figure 3b The filter element 10 is arranged in filter position FP.

[0044] The tumble dryer 15 comprises a process chamber 16, which is arranged within a drum 16a. In other words, the process chamber 16 is bounded by, or formed within, a drum 16a. The drum 16a contains agitators 23 designed to circulate the laundry. The process chamber 16 can be filled with laundry through a loading opening 17. The loading opening 17 includes a closable loading hatch 17a. The tumble dryer 15 has three filter elements 10. The three filter elements 10 are arranged in series. Heat exchangers are arranged below the process chamber 16. The heat exchangers are an evaporator 18 and a condenser 19. A reservoir 20 for condensed water is located below the heat exchangers. Furthermore, a fan 21 is arranged below the process chamber 16 to generate a process airflow PL.

[0045] The process airflow flows along an air path L. Starting from the fan 21, the process airflow PL flows through a process air duct 22, which is located on a wall opposite the loading opening 17 or on a rear wall. The process airflow PL is directed into the process chamber 16 via the process air duct 22. The direction of the process airflow PL is indicated by arrows. The process airflow passes through the process chamber 16. During operation, the air absorbs moisture from the laundry being dried. The process airflow PL flows towards the loading opening 17.

[0046] The three filter elements 10 are arranged downstream of the process chamber 16 in the direction of flow. The three filter elements 10 are arranged in series, one after the other, in the direction of flow. A first filter element 10a is arranged in the loading hatch 17a of the feed opening 17. The first filter element 10a can, for example, be designed as a coarse sieve. The first filter element 10a can, for example, have a circular geometry, particularly an outer geometry. The first filter element 10a preferably corresponds to the geometry of the feed opening 17 or the loading hatch 17a. The first filter element 10a is in Figure 3a The first filter element 10a is arranged in the open position OP. For this purpose, it is movably mounted on the loading hatch 17a about a pivot point. In other words, the first filter element 10a is pivotably connected to the loading hatch 17a.

[0047] The second filter element 10b is located below the loading hatch 17a. The second filter element is also pivotally connected to the clothes dryer 15. The flow direction through the second filter element 10b is perpendicular to the flow direction through the first filter element 10a. The second filter element can have a textile or mesh structure to filter the process airflow PL. Alternatively or additionally, the second filter element 10b can, for example, be a V-shaped filter element 10 according to [reference to relevant figure]. Figure 1b or a W-shaped filter element 10 as in Figure 2b be designed.

[0048] The third filter element 10c is arranged upstream in the direction of flow. More precisely, the third filter element 10c is arranged upstream of the evaporator 18 in the direction of flow. In particular, the third filter element is positioned immediately upstream of the evaporator 18. The third filter element 10c is pivotably mounted on the clothes dryer 15 about a pivot axis.

[0049] Other embodiments of the present invention are possible and can be understood and carried out by persons skilled in the art when applying the claimed subject matter by studying the figures, the disclosure, and the appended claims. In particular, the respective parts / functions of each embodiment described above can also be combined with one another. Furthermore, various steps of the method can be carried out in a different order than disclosed herein. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are mentioned in interdependent claims does not mean that a combination of these measures cannot be advantageous. Any reference numerals in the claims should not be interpreted as limiting the scope of the claims. Reference symbol list:

[0050] L Air path PL Process air flow FP Filter position OF Open position 10 Filter element 11 Filter system 12 Inlet area 13 Outlet area 14 Filter section 15 Clothes dryer 16 Process chamber 16a Drum 17 Loading opening 17a Loading hatch 18 Evaporator 19 Condenser 20 Reservoir 21 Fan 22 Process air duct 23 Drive unit

Claims

1. Filter element (10) for a clothes dryer (11) which is designed to be arranged in an air path (L), - wherein the air path (L) is designed to guide a process air flow (PL), - wherein the filter element (10) comprises a mechanism (M) which is designed to allow the filter element (10) to be transferred into a filter position (FP) and into an open position (OP).

2. Filter element (10) according to claim 1, wherein the filter element (10) comprises a sieve, a foam and / or a textile.

3. Filter element (10) according to claim 1 or 2, wherein the filter element (10) has a wedge-shaped geometry.

4. Filter element (10) according to any of the preceding claims, wherein the mechanism of the filter element (10) comprises an actuator and / or is mechanically coupled to an actuator to move the filter element (10) from the filter position (FP) to the open position (OP) and / or vice versa.

5. Filter system (11) for a clothes dryer comprising: - at least one filter element (10) according to one of the preceding claims, - wherein the filter system (11) comprises an actuator coupled to a mechanism of the filter element (10) to move the filter element (10) into a filter position (FP) and into an open position (OP), - wherein the filter system (11) comprises a control unit to control the actuator depending on at least one system information.

6. Filter system (11) according to claim 5, wherein the filter system (11) comprises a moisture sensor to detect moisture information.

7. Filter system (11) according to one of claims 5 or 6, wherein the filter system (11) comprises a temperature sensor to acquire temperature information.

8. Filter system (11) according to any one of claims 5 to 7 wherein the filter system (11) comprises a flow sensor and / or a pressure sensor to acquire pressure information and / or volume flow information.

9. Clothes dryer with a filter element (10) according to one of claims 1 to 4 and / or a filter system (11) according to one of claims 5 to 8.

10. Method for operating a filter system (11) according to one of claims 5 to 8 or a clothes dryer with such a filter system (11) comprising the following steps: - Acquiring and / or providing at least one system information, - Transmitting the system information to a control unit, - Transferring at least one filter element (10) into a filter position (FP) or into an open position (OP) based on the at least one system information.

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