Filter device and tumble dryer containing the filter device

Abstract

Filter device (1) for a tumble dryer, wherein the filter device (1) comprises a frame (2) and a filter element (3) held by the frame (2), and wherein the filter element (3) is permanently connected to the frame (2) or inserted into the frame (2), wherein the frame (2) is formed from two frame parts (2a, 2b) which are permanently connected to one another and wherein the filter element (3) is inserted between the two frame parts (2a, 2b), wherein the two frame parts (2a, 2b) are permanently connected to one another by a means selected from the group consisting of a snap connection means (4a, 4b), a welded connection and an adhesive connection.

Description

The present invention relates to a filtering device and a clothes dryer including the filtering device. In particular, the present invention relates to a filter device for a tumble dryer, with which it is possible to prevent the tumble dryer from being operated without the filter device.A tumble dryer comprises, among other things, a drum rotatably mounted in a housing, a charging opening closable by a door, a front wall and a blower and a heating device for generating a process air flow in a flow channel, wherein the process air flow flows via a heat exchanger.The process air stream flows around the heat exchanger present in the tumble dryer, in which process air stream various solid constituents are entrained, which originate on the one hand from the detergents used and on the other hand from the laundry items to be dried. These solid constituents settle over time on the surfaces of the heat exchanger around which the process air stream flows in the form of coatings composed of organic and inorganic constituents. The organic constituents of the coatings consist of hair and lint from the laundry items, whereas the inorganic constituents of the coatings are composed predominantly of zeolites, sulfates and water hardeners, such as, for example, magnesium and calcium salts.The coatings on the heat exchanger surfaces lead to a reduction in the power capability of the heat exchanger. In order to prevent or at least restrict this, a rinsing system for the heat exchanger is therefore provided in high-quality and expensive tumble dryers, which rinsing system frees the heat exchanger surfaces from such coatings at specific time intervals. However, such a flushing system is usually not used in more cost-effective tumble dryers, so that in these appliances the heat exchanger surfaces must be kept free of such coatings in another way.For this purpose, in more cost-effective tumble dryers, a filter insert which is accessible from the outside via a inspection flap arranged in the front wall of the housing and which contains a filter element which is usually a foam material with a pore size suitable for the intended purpose is arranged upstream of the flow duct. The filter insert must be removed from the tumble dryer from time to time in order to remove the organic and inorganic constituents retained in the filter element from the process air stream, for example by washing out. The filter element is usually removed from the filter insert in order to facilitate washing out. After the filter element has been cleaned, it is introduced again into the filter insert and the filter insert is inserted again into the tumble dryer.A filter insert known from EP 2 309 053 A1, which is also referred to as a "handle", for a tumble dryer comprises a filter element which is a planar foam material, filter fixing elements and a grip shell with locking elements. Since no constructional measures are provided in such a filter insert which prevent the handle shell from being inserted without the filter element into a tumble dryer, there is the possibility that the handle shell is inserted without the filter element. However, the permanent operation of the tumble dryer without the filter element leads to the above-mentioned reduction in the output capability of the heat exchanger.Furthermore, WO 2005 / 090 669 A2 describes a filter insert for a tumble dryer, in which the filter element is accommodated in a hinged frame which is fixedly mounted on a handle shell. In this filter insert as well, due to the foldability of the frame, there is the possibility that the filter insert is inserted into the tumble dryer without the filter element after cleaning.DE 197 05 616 A1 discloses a lint filter device for a tumble dryer which is designed with a coarse filter and a fine filter. EP 2 584 086 A1 discloses a tumble dryer with a lint filter device which is arranged in an outlet circuit. EP 2 455 537 A1 discloses a tumble dryer with a filter block. DE 202007014571 U1 describes a filter for a tumble dryer which is arranged in a frame. DE 84 37 357 U1 shows a tumble dryer which has a lint filter with a foldable frame.With regard to the known solutions, the object of the present invention is to specify a filter device for a tumble dryer, with which it is possible to reliably prevent a filter element present in the filter device from being inserted into the tumble dryer when the tumble dryer is operated. Another object of the present invention is to provide a clothes dryer in which the filter member is inserted.The objects of the invention are achieved by the filter device and the tumble dryer according to each independent claim. Further developments and preferred embodiments of the invention are defined in the dependent patent claims, in the following description and in the drawing attached to the figures. Embodiments of the filter device correspond here to embodiments of the tumble dryer and vice versa, and this also if not explicitly pointed out here.According to the invention, a filter device for a tumble dryer is provided, which filter device has a frame and a filter element held by, in particular in, the frame, and wherein the filter element is non-detachably connected to the frame or inserted into the frame.The frame has a shape which is customary for use in tumble dryers and can be embodied, for example, as rectangular or square, preferably rectangular. Furthermore, the filter element is non-detachably inserted into the frame or is non-detachably held by the frame. In this context, non-detachable means in particular that it is not possible to remove the filter element from or from the frame without the frame and / or the filter element being damaged or even rendered unusable. In particular, a non-detachable connection is understood to mean an adhesive or welded connection between the frame and the filter element.This makes it possible to prevent the frame from being inserted into a tumble dryer without the filter element in a simple manner. Since, furthermore, the frame is always connected to the filter element, the presence of the filter element in the tumble dryer is always detected by suitable means by detecting the presence of the frame in the tumble dryer. In contrast to the above-described filter insert of the prior art, in which the filter element is accommodated in a hinged frame, it is therefore ruled out that, when the filter device is inserted, no filter element is located in the tumble dryer.According to a preferred embodiment of the filter device, the frame is made of a thermoplastic material.The thermoplastic resin is not particularly limited, and for example, polypropylene (PP), acrylonitrile butadiene styrene (ABS) providing a comparatively rigid frame may be used.However, thermoplastic elastomers (TPE) can also be used as thermoplastic, such as thermoplastic elastomers based on olefins (TPE-O or TPO) or thermoplastic elastomers based on urethane compounds (TPE-U or TPU), preferably TPU. Since thermoplastic elastomers are comparatively flexible, a filter device in which the two frame parts are made of a TPE and the inserted filter element is also flexible can be deformed greatly. This facilitates the removal of dirt particles and / or fibers when washing out the filter element with water, since the filter device can be rotated in itself, which corresponds to a drying out of textiles.The frame is formed from at least two frame parts which are non-detachably connected to one another. The filter element is inserted, preferably non-detachably, between the two frame parts. The two frame parts can be produced in a manner known per se, for example by injection molding.The at least two-part frame enables simple production of the filter device. The division of the frame into the two or optionally more frame parts is not particularly limited and can be carried out, for example, in a plane which is orthogonal to the thickness direction of the inserted filter element or else in a plane which is parallel to the thickness direction of the inserted filter element. For stability reasons, however, it is preferred to divide the frame into the two or optionally more frame parts in a plane orthogonal to the thickness direction of the inserted filter element.The two frame parts are non-detachably connected to one another. In this context, non-detachable means in particular that it is not possible to separate the two frame parts without the frame parts and / or the filter element being damaged or even rendered unusable. In particular, a non-detachable connection is understood to mean an adhesive or welded connection between the frame parts. Furthermore, the filter element is inserted in a non-removable (non-removable) manner, preferably non-detachably, between the two frame parts or non-detachably connected to the frame parts.The two frame parts are non-detachably connected to each other by a means selected from the group consisting of a snap-in connection means, a welded connection and an adhesive connection.In the snap-fit connection means, which can be used for non-detachably connecting the two frame parts, when the two frame parts are assembled, a joining part which protrudes from one frame part deforms elastically and subsequently non-detachably hooks into a corresponding opening which is present in the other frame part. According to the invention, at least two snap-in connection means, preferably four or more, are provided in order to ensure a sufficiently firm connection of the two frame parts. The snap connection is preferably designed such that it cannot be released manually. A snap-in connection, once snapped in, is therefore not releasable again in a non-destructive manner.Alternatively, the two frame parts can also be joined in an unreleasable manner by means of a welded connection, for example by means of ultrasonic welding, or by means of an adhesive connection to an adhesive suitable for the respective material of the frame.Depending on the connection method used for the two frame parts, the filter element used can already be inserted in the frame so firmly without additional fastening means that it cannot be detached from the frame without being damaged or even rendered unusable. In cases where the inserted filter element could still be detached from the frame, the filter element must be fixed in the frame by additional fastening means, such as by a suitable adhesive connection.As mentioned above, since the frame is always connected to the filter element according to the invention, by detecting the presence of the frame in the tumble dryer by suitable means, the presence of the filter element in the tumble dryer can be detected.Such a suitable means is, for example, a mechanical switch which is arranged in a region inside the tumble dryer into which the filter device is inserted. The mechanical switch is preferably arranged such that when the filter device is fully inserted into the tumble dryer, the frame presses a protruding actuating means of the switch, whereby an actuating signal is conducted from the actuated switch to a control device of the tumble dryer, which then enables the operation of the tumble dryer.The force required for the actuation of the mechanical switch is selected in such a way that both a rigid design of the frame (e.g. made of PP) and a comparatively flexible design of the frame (e.g. made of TPU) can sufficiently actuate the actuating means of the switch, so that an actuating signal can be conducted to the control device of the tumble dryer.According to a preferred embodiment of the filter device, the frame comprises an integrated magnet. The magnet can be integrated into the frame, for example, during production by injection molding. In order to detect the presence of the magnet after the filter device has been fully inserted into the tumble dryer, a reed contact or a Hall element can be provided in a manner known per se in an area within the tumble dryer into which the filter device is inserted, which reed contact or Hall element can output an actuation signal in the presence of the magnet, which can be conducted to the control device of the tumble dryer.According to a preferred embodiment of the filter device, the filter element is formed from a foam material. Although the material of the filter element is not particularly limited, a foam material is preferably used, since its production is particularly cost-effective and thus a very good filtering effect is achieved and simple cleaning is possible. If the frame is made of a thermoplastic elastomer, a flexible foam material is preferably used, since the above-described twisting capability of the frame can then be used to facilitate cleaning of the filter device.The invention further relates to a filter insert having a base body and a filter device which can be detachably fastened thereto. The filter insert thus contains a removable and reusable or remountable filter device. The base body can in particular have a grip element (handle) or a grip shell, as well as filter fixing elements for fixing the filter device to the base body.Furthermore, according to the invention, a tumble dryer is provided having a drum rotatably mounted in a housing, a charging opening closable by a door, a wall, in particular a front wall, and a fan and a heating device for generating a process air flow in a flow channel, wherein the process air flow flows via a heat exchanger, upstream of which a filter insert, which is accessible from the outside, preferably via a inspection flap arranged in the wall or front wall of the housing, is arranged in the flow channel, wherein the filter insert contains a filter device according to the present invention.According to the invention, the filter device can be used in any tumble dryer which requires a filtering of a process air stream. As stated above, the tumble dryer preferably comprises a device for detecting the presence of the filter device, such as a reed contact, a Hall element and / or a mechanical switch.Thus, it is possible to provide a laundry dryer in which a filter member provided in the filter device can be reliably prevented from being inserted into the laundry dryer when the laundry dryer is operated. In particular, it is possible to prevent a frame of a filter device without an associated filter element from not being inserted into the tumble dryer when the tumble dryer is operated.On the basis of an exemplary embodiment illustrated in the figures of the appended drawings, which is not to be understood as limiting, further details, features and advantages of the present invention are described in more detail below. In the drawings, FIG. 1 is a perspective view of a filter device illustrating a state before the parts of the filter device are assembled, FIG. 2 is a perspective view of a filter device illustrating a state after the parts of the filter device are assembled, FIG. 3 is an exploded view of a filter insert which comprises a filter device, FIG. 4 is a perspective view of the filter insert according to FIG. 3, and FIG. 5 shows a tumble dryer in which the filter device is inserted by means of a filter insert.As shown in FIG. 1, the filtering device 1 for a laundry dryer according to the present invention includes a frame 2 and a filter member 3. The frame 2 is formed from two frame parts 2a, 2b. In the embodiment shown, the frame 2 is divided into the two frame parts 2 a, 2 bin a plane which is orthogonal to the thickness direction of the filter element 3 to be inserted. Further, in the embodiment shown, the frame part 2a comprises a plurality of snap-connection joining parts 4a, and the frame part 2b comprises a plurality of corresponding snap-connection openings 4b.To produce the filter device 1, the filter element 3 is first placed in the frame part 2 b, on the inner edges of which an adhesive is applied on several regions for fixing the filter element 3 to the frame part 2 b. Subsequently, the frame part 2 ais moved in the direction of the frame part 2 bwith the filter element 3 inserted and pressed in the direction of the frame part 2 bsuch that the snap connection joining parts 4 aare inserted into the snap connection openings 4 band finally snap into place therein. Due to the design of the snap connection joining parts 4 aand the snap connection openings 4 b, the frame part 2 ais thereby non-detachably attached to the frame part 2 b. The adhesive on the frame part 2b ensures additional fixing of the filter element 3, so that the latter is non-detachably connected to the frame 2. The finished filter device 1 is shown in FIG. 2.The filter device 1 shown in FIG. 2 is subsequently assembled to form a filter insert 11 (usually referred to as a "handle"). An embodiment of such a filter insert 11 comprising a filter device 1 according to the invention is shown in an exploded view in FIG. 3 and in the assembled state in FIG. 4. The filter insert 11 shown in FIGS. 3 and 4 comprises the filter device 1 according to the invention, tubular filter fixing elements 5 and a grip shell 6, which can be gripped by the user for inserting the filter insert 11 into the tumble dryer. The filter cartridge 11 is assembled by inserting the filter fixing members 5 into dedicated holes of the filter element 3 and then attaching the filter fixing members 5 to dedicated holders (not shown) of the grip shell 6.The filter fixing elements 5 are preferably mechanically coupled to at least one of the frame parts 2 a, 2 b. The frame parts 2 a, 2 bcomprise in each case a first contact surface for bearing against a circumferential narrow side of the filter element 3 and a second contact surface for bearing against an edge region of the filter surface (inflow or outflow surface) of the filter element 3. Alternatively or additionally, it is possible that the manual removal of the filter element 3 from the frame 2 is prevented in that the frame elements 2 a, 2 beach have at least one cross strut 13 which extends along a filter surface of the filter element, in particular along an inner region (not edge region) of the filter surface. The cross strut 13 preferably extends between two segments or sections of the encircling frame part of the frame element 2 aand 2 b, respectively.A tumble dryer 7, in which the filter insert 11 can be used, has a drum rotatably mounted in a housing 8, a charging opening closable by a door 9, a wall 10, in particular a front wall, and a fan and a heating device for generating a process air flow in a flow channel, wherein the process air flow flows via a heat exchanger. The filter insert 11 in the flow channel is arranged upstream of the heat exchanger and can be removed from the outside via a inspection flap 12 arranged in the wall 10 of the housing 8 for cleaning and reused.LIST OF REFERENCE CHARACTERS1 Filter device 2 Frame 2 a, 2 bFrame parts 3 Filter element 4 a Schnapp connection joining part 4 b Schnapp connection opening 5 Filter fixing element 6 Handle shell 7 Tumble dryer 8 Housing 9 Door 10 Wall 11 Filter insert 12 Inspection flap 13 Transverse strut

Claims

Filter device (1) for a tumble dryer, wherein the filter device (1) has a frame (2) and a filter element (3) held by the frame (2), and wherein the filter element (3) is non-detachably connected to the frame (2) or inserted into the frame (2), wherein the frame (2) is formed from two frame parts (2a, 2b) which are non-detachably connected to one another, and wherein the filter element (3) is inserted between the two frame parts (2a, 2b), wherein the two frame parts (2a, 2b) are non-detachably connected to one another by a means selected from the group consisting of a snap connection means (4a, 4b), a welded connection and an adhesive connection.The filtering device (1) for a laundry dryer according to claim 1, wherein the frame is made of a thermoplastic resin.The filter device (1) for a laundry dryer according to claim 2, wherein the thermoplastic resin is a thermoplastic elastomer.The filtering device (1) for a laundry dryer according to any one of claims 1 to 3, wherein the frame (2) comprises an integrated magnet.The filter device (1) for a laundry dryer according to any one of claims 1 to 4, wherein the filter element (3) is formed of a foam material.The filter device (1) for a laundry dryer according to claim 5, wherein the foam material is flexible.Laundry dryer (7) having a drum rotatably mounted in a housing (8), a charging opening closable by a door (9), a wall (10) and a fan and a heating device for generating a process air flow in a flow channel, wherein the process air flow flows via a heat exchanger, upstream of which is arranged a filter insert (11) in the flow channel, said filter insert being accessible from the outside via a inspection flap (12) arranged in particular in the wall (10) of the housing (8), wherein the filter insert (11) contains a filter device (1) according to one of claims 1 to 6.Laundry dryer (7) according to claim 7, wherein the laundry dryer comprises a means for detecting the presence of the filtering means (1).

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