WO2008074581A1 - Method and device for drying laundry by means of an air current, and household appliance containing such a device - Google Patents

Abstract

When laundry (1) is dried in a drum by means of an air current guided through the drum, the air current is guided through a filter (8) which catches the fluffing (9) carried therewith. A scraper (17) carrying out a movement for scraping fluffing (9) caught in the filter and a collecting region comprising an opening for receiving the scraped fluffing (9) are associated with said filter. The scraper (17) is monitored during the movement thereof to ensure that it reaches a certain pre-determined position.

Description

 Method and apparatus for drying laundry by means of an air flow and household appliance containing such a device

The present invention relates to a method and apparatus for drying laundry by means of an air flow, comprising a drum for receiving the laundry and a duct system for guiding the air flow, the duct system having a downstream side of the drum portion, in which the air flow in a descending direction is guided and in which a sieve arranged to catch fluff from the air flow and the sieve a movement exporting scrapers for stripping trapped lint and a collecting space are associated with an opening for receiving stripped lint. The invention further relates to a device containing a device of the type mentioned above household appliance.

It is already a household clothes dryer with a movable device, which is inevitably operated by an operator at the end of a drying process, and with a arranged in an exhaust duct lint filter known (DE 44 03 183 C2). In this case, a scraper movable in the direction of an opening of a collecting space is arranged above the sieve surface of the lint filter and is operatively connected to the movable device of the tumble dryer. The relevant mobile device is either a loading door of the household clothes dryer, at the opening of the scraper is moved by means of a gear-rack gear on the lint filter, or an electric motor whose rotation is converted via a corresponding gear in a translational movement. By means of this translatory movement, the abovementioned scraper pushes lint removed from the lint filter into the aforementioned collecting space. However, a monitoring of the movement of the scraper is not provided in the relevant known household laundry dryer meanwhile. Thus, a faulty operation of the scraper can not be readily recognized. However, there is a desire to recognize such a disturbed operation of the relevant scraper and to be able to take appropriate countermeasures.

Furthermore, a method for operating a household laundry drier with a flow filter for a dry air flow and a device controlled by a monitoring and control device of the household laundry drier for cleaning the lint filter is known (DE 199 24 297 A1). In this known method, the cleaning device of the lint filter is controlled so that during the predominant operating time the lint filter is covered with a lint, which itself has filtering effect. The relevant additional lint felt improves the filter effect and is in particular able to retain even small ultrafines, so that the drying air duct and in particular a condenser in the dry air flow have become less fluffy and less likely to be cleaned. For this purpose, in particular a constant thickness of the lint felt during operation is sought. For example, for this purpose, the cleaning device only remove a part of the accumulated lint, so that constantly a lint layer of a certain thickness remains on the filter.

The above-mentioned cleaning device is formed by a filter associated with the lint collector with a drive which is controlled by a monitoring and control device of the household laundry dryer. The lint collector moves parallel to the filter surface, collecting lint that has settled on the filter as it moves, and delivering it to a lint collector, from which it can be removed by an operator as needed. In order to determine the effectiveness of the lint filter, the pressure drop on the lint filter is additionally monitored. In this way, although a proper work of the lint filter can be largely recognized, but it can not be determined easily whether the mentioned lint collector his movement parallel to the filter surface also performs properly or is disturbed in its movement. However, such a finding is highly desirable for smooth cleaning of the lint filter.

There is also known a lint filter device for an air flow in a household laundry drier with an endless circulating element (EP 1 050 619 B1). The trajectory of this endless circulation element is crossed at a first location by the air flow. In addition, the circulating element in question has a filter element which is arranged in a process phase in which there is a need for filtering, at the location of the first intersection of the air flow with the movement path and which in a cleaning phase by means of a circulating air movement of the circulation element to a device for removing of lint from the surface of the filter element is vorbeiführbar. The circulating element in question also has a second section, which is located in the process phase at the location of a second intersection of the air flow with the trajectory of the circulating element in the direction of the air flow behind the location of the first intersection and which is formed großmaschig. As a result, little or no lint can get caught on it. Even with this known lint filter device, no measures are met to monitor a proper discharge and collection of lint or to determine a disturbed operation in the removal and collection of lint.

Finally, an apparatus for drying laundry by means of an air flow has also been proposed (DE 10 2005 054 683.8), comprising a drum for receiving the laundry and a duct system for guiding the air flow, the duct system having a section arranged downstream of the drum, in which the air flow is guided in a descending direction and in which a screen for catching lint from the air flow is arranged and the screen is associated with a scraper in the form of a scraper for stripping trapped lint and a memory with an opening for receiving stripped lint. The doctor is preferably driven by an electric motor. Although in this proposed device a structurally quite compact constructed and effective lint scraper device is provided, yet no measures for monitoring the proper operation or to determine an optionally present disturbed operation of the scraper or the squeegee are taken. However, as stated above, such monitoring is highly desirable.

A faulty operation of a scraper can have different causes. Thus, the scraper may be blocked in his leadership before the sieve or lint filter, on the sieve or behind the sieve. In the case of blocking the scraper in front of the sieve this is thus not cleaned; in case of blockage of the scraper on the screen, a defective screen may be present and lint may not be filtered. In the case of a blockage of the scraper after the sieve but before the plenum lint are not discharged into the respective collection space, and the guide of the scraper can clog. Moreover, the reason for blocking the scraper may be a failure of the scraper drive. If such errors or images are not recognized, it can lead to follow-on errors that can put at least a proper operation of a washer or dryer in question.

The invention is therefore based on the object to show a way, as in a method and apparatus of the type mentioned, the cleaning process of serving for catching lint from an air stream sieve to relatively simple and effectively monitor its proper operation and report an incident.

The above object is achieved in a method of the type mentioned in the present invention, characterized in that in the course of said movement of the scraper, the achievement of at least a certain, fixed movement position is monitored.

The invention has the advantage that it can be monitored in a relatively simple, yet effective manner, whether said scraper performs any movement with respect to said lint collecting screen and thus its Flusenabstreiffunkti- on. For this purpose, the movement of the stripper in question is monitored at least one specific fixed movement position. If the scraper concerned reaches this movement position or overflows it, this is considered to be a proper work of the relevant scraper. If, on the other hand, the at least one specific fixed movement position is not reached or overrun by the scraper in question, this is regarded as an error case which can be reported or displayed by issuing an alarm signal, for example after a certain period of time has elapsed since the time at which the alarm was triggered Move. Then, necessary measures can be initiated, such as, for example, the stopping of further operation and / or the calling-in of service personnel in response to the mentioned message or indication signal.

Preferably, a sensor signal is emitted by the scraper on reaching the at least one specific fixed movement position. This brings with it the advantage of a particularly simple possibility of being able to easily monitor the achievement of the at least one specific, fixed movement position of the scraper.

Advantageously, in addition, a proper accommodation of a lint collection container is monitored in said collection space. Namely, this combined monitoring of reaching at least a certain fixed movement position by said scraper and the proper placement of the FIus senungsammelbehälters in the collecting space can ensure a safe lint collecting. Due to the additional monitoring of the proper placement of the lint collector in said collection space can be for on the other hand, an undesirable distribution of lint removed by the wiper due to the monitoring involved can be avoided. If said lint collecting container is not properly accommodated in the collecting space, this is determined by the mentioned monitoring, and a corresponding reporting signal can be given which can be used to stop the operation and / or call service personnel.

The above-mentioned proper housing of the lint collector in the collecting space is expediently monitored by evaluating at least one sensor signal triggered by the relevant storage. This results in the advantage of a particularly simple possibility of monitoring the proper placement of the lint collector in said collection space.

Preferably, upon detection of improper operation of the wiper in the course of said monitoring, a report signal is issued. This has the advantage that measures required in a simple manner by the relevant message signal can be initiated, such as the already mentioned stopping of further operation and / or the calling of service personnel.

On the other hand, the object underlying the invention in a device of the type mentioned in the present invention is achieved in that a movement of the scraper with respect to at least one specific fixed movement position by means of a sensor arrangement can be monitored.

This results in the advantage of a particularly low design effort to determine a movement of the scraper with respect to at least one particular fixed movement position and thus to monitor.

Preferably, a proper housing of a provided for collecting collected from the scraper lint fluff collection container in the said collection space can be monitored. This has the advantage that proper collection of the lint removed from the wire by means of the wiper can be monitored. Namely, such collecting is ensured only when the lint collecting container is properly accommodated in the collecting space. Advantageously, the proper placement of the lint collector in the said collection space can be monitored by means of a sensor arrangement. This makes it possible to monitor in a particularly simple manner the proper placement of the lint collector in said collection space.

In a particularly advantageous manner, these just mentioned sensor arrangement and the above-mentioned sensor arrangement, with which a movement of the scraper with respect to at least one specific fixed movement position can be monitored, combined or formed by one and the same sensor arrangement. This has the advantage that can be done with a particularly low design effort for the two monitors.

Conveniently, the respective sensor arrangement is formed by a tactile or non-contact sensor. This has the advantage that in each case a structurally simple, yet safe sensor arrangement can be used. The use of contactless sensors over tactile sensors also has the advantage that the so-called process air duct - through which the above-mentioned air flow possibly passes with lint - need not be partially opened. In this way, otherwise possibly occurring leakage losses of the air flow and malfunction due to exiting moist air (corrosion phenomena, circuit uncertainties) can be avoided in a simple manner. In part, such partial openings could indeed be sealed, however, the areas for such openings are difficult to make reliable and mean a significant, undesirable overhead.

It is also advantageous to provide a switch or limit switch or a piezo element as a tactile sensor. In this way, particularly simple and relatively small sensors can be used.

On the other hand, at least one light barrier, a Hall sensor, a light coupler, in particular an IR coupler or an inductive sensor can be advantageously provided as non-contact sensor. This has the advantage that it provides non-contact sensors which can be used in a device environment which is less well suited for tactile sensors. According to a further expedient embodiment of the invention, when using a Hall sensor for monitoring the at least one specific fixed movement position, in particular an end position of the scraper attached to this a magnetic field emitting magnetic part, which acts with its magnetic field on the Hall sensor, and the Hall sensor is arranged stationary relative to the relevant magnetic part in the region of said specific fixed movement position of the scraper. By these measures, there is the advantage of a particularly simple and effective monitoring of the reaching or overflow of at least one specific fixed movement position of the scraper by the scraper by means of a single Hall sensor.

Preferably, with the aforementioned a Hall sensor for monitoring a certain fixed movement position, in particular the end position of the scraper additionally a proper recording of the lint collection container in the said collection chamber monitored. The lint collector in question also has a magnetic field emitting magnetic part, whose magnetic field acts on the Hall sensor. By this measure, there is the advantage that the relevant one Hall sensor can be exploited for simultaneous monitoring, namely, on the one hand for the monitoring of the achievement of said certain fixed movement position, in particular the final position by the scraper and on the other for a proper recording of the lint collector in the collection room. Namely, the magnetic fields of the two mentioned magnetic parts will act in combination to assist the Hall sensor and cause the latter to emit a Hall voltage indicative of the proper operation of the device.

Conveniently, according to the present invention, a device as previously specified is contained in a domestic appliance, particularly in a washer or dryer. Such a dryer is thus particularly safe to operate in terms of fluff removal in an advantageous manner.

With reference to drawings, the invention will be explained in more detail below on some embodiments. In the drawings show 1 schematically shows a cross section through a laundry dryer to which the present invention can be applied,

2 shows in a schematic representation and partly in section a device according to a first embodiment of the invention with a first sensor arrangement,

3 shows in a schematic representation and partly in section a device according to a second embodiment of the invention with a second sensor arrangement,

Fig. 4 in a fragmentary schematic representation and partly in

FIG. 2 shows a section through a device according to a third embodiment of the invention with a third sensor arrangement, FIG.

Fig. 5 in a fragmentary schematic representation and partly in

FIG. 2 shows a section through a device according to a fourth embodiment of the invention with a fourth sensor arrangement, FIG.

6 shows schematically in a fragmentary schematic representation and partly in section a device according to a fifth embodiment of the invention with a fifth sensor arrangement,

7 is a simplified schematic representation of a sixth sensor arrangement which can be used instead of the sensor arrangements provided in the apparatuses according to FIGS. 2 to 6, and

8 shows, in a simplified schematic illustration, a seventh sensor arrangement which can be used there instead of the sensor arrangements provided in the devices according to FIGS. 2 to 6.

Before going into detail about the individual drawings, it should be noted that in the various drawings, the same elements or parts are denoted by the same reference numerals. Incidentally, in connection with the individual drawings, only those elements or parts with which the devices shown in the respective drawings differ from those described above with reference to the drawings will be described in more detail.

In the washing or tumble dryer schematically shown in Fig. 1, in which the present invention is applicable, laundry 1 is dried by means of an air flow in a drum 2, which is provided for receiving the laundry 1. The drum 2 is rotatable about an axis 3 to shake the laundry 1 in the air flow. Of the Air flow is led away in a channel system 4, 5, 6 of the drum 2 and this fed back. The channel system 4, 5, 6 comprises a falling section 4, which passes partly through a bearing plate 7 for loading the drum 2, a horizontal portion 5 below the drum 2 and a rising portion 6, through which the air flow back to the drum 2 , The falling section 4 contains a sieve 8, which is arranged in the bearing plate 7 and from which the lint 9, which entraises the air flow of the laundry 1, traps. By means of one of the devices shown in FIGS. 2 to 8, collected lint 9 from the screen 8 - which thus represents a lint filter - are stripped to ensure the lowest possible flow resistance of the wire 8.

In the following on the falling section 4 horizontal section 5, a heat exchanger 10 is provided, in which the air flow is cooled to condense entrained water vapor. Condensed water is separated and disposed of by known per se and not shown in Fig. 1 facilities from the air stream. In the following on the horizontal portion 5 rising portion 6, a fan 1 1, which causes the air flow through the drum 2 and the channel system 4, 5, 6, and a heater 12 is arranged, through which the air flow before entering the drum. 2 is heated again. The heat exchanger 10 and the heating device 12 may optionally be wholly or partly associated with a recuperative heat transport system, in particular to a heat pump. The bearing plate 7 forms on the one hand a support structure for a front side of the device and a front support for the drum 2, and on the other hand it carries a door 13 for closing the drum second

In the illustration according to FIG. 2, which shows schematically and partly in section a device according to the first embodiment of the invention with a first sensor arrangement, the screen 8 provided in the washer / dryer according to FIG. 1 is considered to be in a tunnel-shaped hollow body 14 containing shown. The hollow body 14 extends in the direction of the width of the washer / dryer shown in Fig. 1, and it has, for example, a round cross-section. The respective tunnel-shaped hollow body 14 preferably carries the screen 8 only in that area which adjoins an entry area for the air stream emerging from the drum 2 according to FIG. 1. Based on the illustration in FIG. 2, this means that, for example, the illustrated upper region of the tunnel-shaped hollow body 14 serves as the entry region, and thus the sieve 8 only following this entry region in the lower region is received by the respective hollow body 14. The mentioned air flow thus flows as shown in FIG. 2 from top to bottom through the hollow body 14 and through the sieve 8, which traps lint 9 entrained by the air flow in question.

The tunnel-shaped hollow body 14 has in its longitudinal direction on two opposite end portions 15, 16, between which a scraper 17 preferably only in the longitudinal direction of the respective hollow body 14 back and forth, as illustrated by an indicated in Fig. 2 double arrow 18, and optionally is additionally rotatable about its central axis during its longitudinal movement. The end region 15 is here preferably a closed end region, and the end region 16 is an open end region. The scraper 17 may, for example, be constructed such that it has scraper elements projecting from a carrier plate, for example plastic bristles, which point to the left in the illustration according to FIG. 2 and with which the scraper 17 moves from the right side to the left side in FIG Fig. 2 lint 9 stripped from the screen 8 permits. This lint 9 moves the scraper 17 into a lint collector 19 attached to its open end region 16, which is received by a collecting space provided there (not shown) in such a way that it sealingly adjoins the open end region 16 of the tunnel-shaped hollow body 14 with its access opening ,

The above-mentioned reciprocating motion of the scraper 17 in the tunnel-shaped hollow body 14 and thus along the screen 8 causes here, for example, an electric drive, the one in Fig. 2 only schematically indicated by the monitoring and control device 22 to a separate operation in operation settable electric motor 20 and a drive spindle 21 includes. This drive spindle 21 cooperates, for example, with a nut part, which is firmly connected to the wiper 17. The relevant electric motor 20 is controlled by a monitoring and control device 22, which is supplied to an input terminal 23, a corresponding control signal, for example, by a at a certain potential U, such as. + 5V or ground potential switch 24.

The monitoring and control device 22, which may be, for example, a microcontroller with its own software is shown in FIG. 2 input side connected to the outputs of at least one with respect to the tunnel-shaped hollow body 14 fixedly arranged Hall sensor 25, with the Reaching or overflowing one certain fixed movement position of the scraper 17 is monitored. This movement position of the scraper 17 is here its end position during its movement in the tunnel-shaped hollow body. In particular, the Hall sensor 25 in question may be a HaII-IC, which may contain in addition to a Hall element nor a processing circuit, such as a Schmitt trigger circuit, which is controlled by the respective Hall voltage of the Hall element and which at a given amplitude of this Hall voltage outputs a fixed output signal, for example a binary signal "1" corresponding output signal (eg + 5V).

In Fig. 2, a second Hall sensor 26 is additionally shown in dashed lines in a likewise determined fixed movement position of the scraper 17. This movement position is the starting or starting position of the scraper 17 in the tunnel-shaped hollow body 14. The relevant second Hall sensor 26 is also connected to the monitoring and control device 22 on the output side.

While the Hall sensor 25 is located at a certain first distance above the opening portion 16 of the tunnel-shaped hollow body 14, the aforementioned second Hall sensor 26 is arranged in a comparatively smaller second distance near the other, closed end portion 15 of the tunnel-shaped hollow body 14. This situation will be discussed in more detail below.

In order to let the two provided in the embodiment of FIG. 2 Hall sensors or HaII ICs 25 and 26 each have a specific evaluable Hall voltage, magnetic fields are required. Such a magnetic field is generated by a magnetic member 27 in the form of a permanent magnet, which is supported by the scraper 17. Another magnetic field is caused in the embodiment of FIG. 2 by a magnetic member 28 in the form of a permanent magnet or a magnetic sheet, which is mounted in or on the lint collector 19. 2, the Hall sensor 25 then delivers the mentioned specific evaluable Hall voltage to the monitoring and control device 22 when, on the one hand, the scraper 17 with its magnetic part 27 moves into a certain movement position, in the present case, this is its left end position - has been moved and when, on the other hand, the lint collector 19 has been properly inserted with its magnetic part 28 in the mentioned collection space, so that the relevant lint collector 19 sealingly abuts the end region 16 of the tunnel-shaped hollow body 14 with its receiving opening. In this case, the magnetic part 28 effectively causes a base magnetic signal in the Hall sensor, and the magnetic part 27 provides an additive magnetic signal. Thus, here is a combined monitoring, namely on the one hand to reach a certain fixed movement position (this is the end position) of the scraper 17 and on the other the proper insertion of the lint collector 19 in the space provided for its collection space.

At the end region 15 of the tunnel-shaped hollow body 14 shown on the right in FIG. 2, the Hall sensor 26, which is likewise stationary with respect to the tunnel-shaped hollow body 14, merely determines the reaching of this position by the scraper 17 with its magnetic part 27 Assuming that the two Hall sensors 25 and 26 have approximately the same magnetic sensitivity, the Hall sensor 26 according to FIG. 2 is arranged closer to the tunnel-shaped hollow body 14 than the Hall sensor 25, since the relevant Hall sensor 26 there only a single magnetic field - namely only that of the magnetic part 27 - for delivering a corresponding evaluable Hall voltage acts as it is otherwise discharged from the Hall sensor 25, if on this according to FIG. 2, the magnetic fields of the two magnetic parts 27, 28 act. It should be appreciated that when using a Hall sensor 26 with a magnetic sensitivity increased over the magnetic sensitivity of the Hall sensor 25, this Hall sensor 26 may be located farther away from the tunnel-shaped hollow body 14 than shown in FIG is, for example, at the same distance from the tunnel-shaped hollow body 14 as the Hall sensor 25th

For the position of the Hall sensor 25 shown in FIG. 2, the following should be added. The Hall sensor 25 or the HaII-IC containing the same can, as explained above, be arranged relative to the tunnel-shaped hollow body 14 and the lint collector 19 in such a way that it supplies the mentioned specific evaluable Hall voltage only then, when the scraper 17 is brought into its left end position in the tunnel-shaped hollow body 14 in FIG. 2 and if at the same time the lint collecting container 19 is properly inserted into its collecting space. However, it is also possible to arrange the Hall sensor 25 or the HaII-IC containing the same with respect to the tunnel-shaped hollow body 14 and the lint collector 19, in that the determined Hall voltage or a first edge of an evaluation voltage is output by the relevant Hall sensor 25 to the end region 16 when the fluid collecting container 19 is inserted into the aforementioned collecting space and when the stripper 17 approaches its magnetic part 27 the particular Hall voltage is delivered again or a second edge of the relevant evaluation voltage is still present, when the scraper 17 is moved with its magnetic part 27 further to the end portion 16, for example, in its actual end position. Depending on the components used, the distance between the determination of the two specific evaluable Hall or evaluation voltages can be, for example, between 3 and 6 mm. The distance in question depends, it should be noted here, on the remanence of the magnetic parts or permanent magnets 27, 28 used, on the focusing of the magnetic field lines of these magnetic parts or permanent magnets 27, 28 and on the magnetic sensitivity of the Hall sensor or HaII-IC 25 from. By evaluating the mentioned specific Hall voltage at two different locations of the movement path of the scraper 17 or the mentioned first and second edges of the evaluation voltage of the Hall sensor can thus resolve the movement of the scraper in a particularly advantageous manner.

By the above-described construction of the first embodiment of a device according to the invention shown in FIG. 2, then not only - as explained in the above-considered case - by means of the monitoring and control device 22 reaching at least a certain fixed movement position - in Fig. 2 this two movement positions - are detected by the scraper 17, but it can also be monitored the movement of the scraper 17 in the region of the end portion 16. Such monitoring of the course of movement of the scraper 17 could also by the Hall sensor 26 and optionally provided further, arranged between the end portions 15 and 16 of the tunnel-shaped hollow body 14 Hall sensors - ie by all or at least some provided Hall sensors - along the movement distance of the scraper 17 done.

If the at least one specific fixed movement position is not reached by the scraper 17 in the course of its movement, this is evaluated as an accident, for example after a certain period of time has elapsed since the relevant movement was initiated, and for example by a message issued by the monitoring and control device 22 - and / or display signal signals. In FIG. 3, a device according to the second embodiment of the invention with a second sensor arrangement is illustrated in a schematic representation as in FIG. 2 and partly in section. The relevant second sensor arrangement differs from the first sensor arrangement provided in FIG. 2 in that, instead of the Hall sensor 25, only two schematically indicated reed contacts 29, 30 are provided here, which are connected to the monitoring and control device 22 and the with the mentioned in connection with the description of the device shown in Fig. 2 mentioned magnetic parts or permanent magnets 26 and 27 cooperate. Furthermore, in the embodiment of the device according to the invention shown in FIG. 3, a further reed contact 31 is arranged near the end region 15 of the hollow body 14 shown in FIG. 3. This instead of the Hall sensor 26 in the apparatus of FIG. 2 provided here reed contact 31 is also connected to the monitoring and control device 22 and actuated by means of the scraper 17 carried by the magnetic member or permanent magnet 27 when the scraper 17 is in its starting position shown in Fig. 3 right.

In contrast to the conditions prevailing in the device according to FIG. 2, in the device according to FIG. 3 the movement positions of the scraper 17 moved by the motor 20 by means of the drive spindle 21 and the proper placement of the lint collector 19 in its collecting space are independent of each other in the monitoring - and control device 22 monitors. Incidentally, the reed contacts corresponding to the reed contacts 30, 31 could additionally be arranged along the movement path of the scraper 17 in a definable number and be connected to the monitoring and control device 22. As a result, the course of motion of the scraper 17 between the two end regions 15 and 16 of the tunnel-shaped hollow body 14 could then be additionally monitored.

With regard to the basic monitoring functions, the device shown in FIG. 3 corresponds to the device shown in FIG.

4 shows, in a schematic illustration as in FIGS. 1 and 2 and partly in section, a device according to a third embodiment of the present invention with a third sensor arrangement. With this third sensor arrangement, the movement of the scraper 17 in at least one specific fixed movement position - which is also in In the present case may be the final position of the scraper 17 - monitored. According to FIG. 4, the wiper 17 as wiping elements 32 contains those with a piezoelectric property. This means that the respective stripping elements 32 deliver a specific piezoelectric voltage at their deflection from the electrical connections provided on them. Preferably, all stripping elements 32 are formed by a coherent piezoelectric film. If the scraper 17 thus formed reaches the movement end position shown in FIG. 4 on the left in FIG. 4 in the end region 16, then the respective stripping elements 32 will spring open and therewith an evaluable piezo voltage at connections A1 and A2 of the scraper 17 submit. These terminals A1 and A2 of the scraper 17 are connected to the monitoring and control device 22. In the course of the movement of the respective scraper 17 through the tunnelför- shaped hollow body 14, the mentioned stripping elements 32 are indeed already a bias; However, this does not yet have the magnitude of the voltage which occurs at the terminals A1 and A2 of the scraper 17, when this has reached its movement (end) position in the end region 16.

With regard to the forwarding of the voltage occurring at the terminals A1 and A2 of the scraper 17 to the monitoring and control device 22, it should be noted here that this forwarding in FIG. 4 is indicated only schematically. In practice, the forwarding in question can take place using the electrically conductive drive device of the scraper 17 and an electrically conductive sliding contact arrangement with the monitoring and control device 22.

Although not shown in detail in FIG. 4, the monitoring and control device 22 can be connected to at least one further sensor which detects the correct positioning of the collecting container 19 in its collecting space, as shown for example in FIG. 3. Furthermore, the relevant monitoring and control device 22 may be connected to at least one further sensor, which is arranged along the movement path of the scraper 17. For this purpose, for example, an actuatable by the wiper 17 mechanical switch, such as a micro-switch in question. In addition, the relevant monitoring and control device 22 is also connected in the apparatus of FIG. 4 as in the apparatus of FIGS. 2 and 3 with the drive means 20 for driving the scraper 17. Thus, the device shown in Fig. 4 can operate in principle the same way as the device shown in Fig. 2. 5 shows a schematic representation of a further, fourth embodiment of the device according to the present invention with a fourth sensor arrangement. The fourth sensor arrangement in question, with which the movement of the scraper 17 in the movement end position in the end region 16 of the tunnel-shaped hollow body 14 is determined here, is formed according to FIG. 5 in that at least one scraper element 33 of the scraper 17 has or even has an electrically conductive surface consists entirely of an electrically conductive material, preferably of an electrically conductive metal leaf spring and that relative to the respective stripping element 33, a contact arrangement with two electrically conductive contacts 34, 35 is provided in the end region 16. The two contacts 34, 35 of this contact arrangement, for example, at a distance of 0.5 to 1, 5mm apart. This contact arrangement 34, 35 is here touched by, for example, two electrically conductive and interconnected stripping elements 33 corresponding to the closing of a switch, when the scraper 17 is in its movement end position shown in Fig. 5. For this purpose, the respective stripping elements 33, which consist for example of a material, as it is used for flexible interconnects, carry a thin strip-like metallization. The mentioned electrically conductive contacts 33, 34 are connected to the monitoring and control device 22 explained with reference to FIG. 2, by means of which a monitoring of the reaching of the mentioned movement end position by the scraper 17 is made possible.

In order to monitor the correct insertion of the collecting container 19 into its collecting space, a single microswitch 36 is provided in the embodiment according to FIG. 5, which is also connected with its connections to the mentioned monitoring and control device 22.

In addition, further sensors can be arranged along the path of movement of the scraper 17 and be actuated by it in the course of its movement. All such sensors are also connected to the monitoring and control device 22.

Thus, the device according to FIG. 5 can also work in basically the same way as the device shown in FIG. 2. 6 shows a schematic representation of a further, fifth embodiment of the device according to the present invention with a fifth sensor arrangement. In contrast to the embodiment of the device according to the present invention shown in FIG. 5, in the embodiment of the device according to the present invention shown in FIG. 6, the monitoring of at least one specific fixed movement position of the scraper 17 takes place here in its end position lying at the end region 16 by means of a microswitch 37. The actuator of the relevant microswitch 37 can be actuated by a web portion 38 connected to the wiper 17, with which the microswitch 37 can be closed. The relevant microswitch 37 is connected with its terminals to the monitoring and control device 22 already described in FIG. 2, which monitors the monitoring of the at least one fixed movement position of the scraper 17. The microswitch 37 corresponding microswitches may be provided along the movement path of the scraper 17 of FIG. 6, but at least at a point in the end region 15 of the tunnel-shaped hollow body 14. Thus, here also the course of movement of the scraper 17 can be monitored. In principle, the device according to FIG. 6 works in the same way as the device according to FIG. 2.

7 illustrates in a simplified schematic representation a sixth sensor arrangement by means of which the movement of the scraper 17 can be monitored with respect to at least one specific fixed movement position with a sixth sensor arrangement. This sixth sensor arrangement that can be used in each of the devices according to FIGS. 2 to 6 here consists of a light barrier with a light source 39, which may be, in particular, an infrared (IR) light source, and a light receiver 40 in which it In particular, it may be an infrared (IR) transistor. Between the light source or the light-emitting element 39 and the light receiver 40 is shown in FIG. 7 a the aforementioned scraper 17 moving conveyor belt 41. This example of a flexible material, such as plastic or steel, especially spring steel, existing conveyor belt 41, which by means of in the embodiments according to FIGS. 2 to 6 can be wound up and unwound by means of the motor 20 and thus allows the scraper 17 indicated in FIG. 7 to be moved along its movement path, preferably has passages 42 arranged equidistantly in the longitudinal direction of the conveyor belt. through which the light emitted by the light source 39 can reach the light receiver 40. With the light receiver or phototransistor 40, for example, a counter 43 Be connected on the input side, which can be counted by the phototransistor 40 detected light signals or pulses for monitoring and evaluation. Incidentally, this counter 43 may be included in the monitoring and control device 22, as shown in FIGS. 2 to 6 and with which it is ultimately monitored whether the conveyor belt 41 moves the scraper 17 into at least one specific, fixed movement position or has moved.

In the monitoring and control device 22, the respectively achieved counter position of the counter 43 can be monitored and evaluated. The relevant counter position of the counter 43 can be achieved in that the light barrier consisting of the mentioned light source 39 and the light receiver 40 is arranged at a position remote from the movement end position of the scraper 17 position, in particular at the movement starting position of the respective scraper 17 and then the number of detected by the passage openings 42 in the conveyor belt 41 by the light receiver 40 light signals corresponding to the distance between the respective light barrier and the movement end position of the scraper 17 are counted and compared with a predetermined reference count. This reference count indicates the number of count signals to be counted by the transport belt 41 by passing between the mentioned light barrier passage openings 42 in the conveyor belt 41 during proper transport of the scraper 17. If the counter reading reached by the mentioned counter 43 during the movement of the mentioned conveyor belt 41 into the abovementioned movement end position of the scraper 17 corresponds to the reference count value, this is considered to mean that the scraper 17 is moved by the conveyor belt 41 into the defined, determined movement position. in the present case in a movement end position - has been moved. If a difference between the count of the counter 43 and the relevant reference count is detected - for example, after a certain period of time since the movement of the conveyor belt 41, so this is considered with respect to the transport of the scraper 17 as an error case, which may be to stop the operation and / or can be used to request service personnel.

In a departure from the conditions considered above, the conveyor belt 41 can optionally also be provided with only a single passage opening 42, which is contained in the conveyor belt 41 at a very specific distance from the scraper 17. In this case, the aforementioned photocell consisting of the light source 39 and the light receiver 40 along the trajectory of the scraper 17 may be arranged at a position which is at the same distance as the just mentioned distance from the movement end position of the scraper 17. The determination or the non-detection of the respective one passage opening 42 in the conveyor belt 41 by means of the mentioned light barrier can then be considered to the effect that the scraper 17 has been properly or not properly transported by the conveyor belt 41. In this case as well, as in the case considered above, corresponding display or message signals can be emitted.

FIG. 8 shows in a simplified schematic representation a seventh sensor arrangement according to a modification of the device shown in FIG. 7. In this seventh sensor arrangement, which is also applicable to each of the devices according to FIGS. 2 to 6, has the conveyor belt 41, which is connected to the scraper 17 and which can be wound or unwound by a corresponding drive device, as described in connection with FIG 7, in contrast to FIG. 7, light reflection regions 44 arranged in its longitudinal direction, which are preferably arranged equidistantly, are arranged. Each such reflection region 44 thus allows light emitted by the light-emitting element 39 to reach the light receiver 40 and trigger a corresponding output signal there. This output signal can then be counted by the counter 43 and thus evaluated by the monitoring and control device 22, as has been explained in connection with FIG. 7. Incidentally, in the sensor arrangement according to FIG. 8, the same aspects with regard to the conveyor belt 41 and the monitoring of at least one specific fixed movement position of the scraper 17 moved by means of the conveyor belt 41 may come to bear, as have been explained in connection with FIG. It should be noted that instead of the light barrier used in Fig. 7, a light reflection arrangement is provided, consisting of the light emitting element 39, the light receiver 40 and at least one light reflection region 44 of the conveyor belt 41 shown in FIG.

Finally, it should be noted that the present invention is not limited to devices with the sensor arrangements considered and explained above. Rather, instead of the specified sensor arrangements, other sensor arrangements not considered here can also be used, such as acoustic or capacitive sensor arrangements. Incidentally, in the case of the embodiments explained above, Example provided sensor arrangements other than in the figures described above may be used in a variety of combinations.

LIST OF REFERENCE NUMBERS

Laundry

drum

axis

Channel system, falling section

Canal system, horizontal section

Canal system, rising section

end shield

scree

Fluff 0 Heat exchanger 1 Blower 2 Heating device 3 Door 4 tunnel-shaped hollow body 5 End area 6 End area 7 Scraper 8 Double arrow 9 Collecting tank 0 Electric motor 1 Drive spindle 2 Monitoring and control device 3 Input connection 4 Switch 5 Hall sensor 6 Hall sensor 7 Magnetic part 27, permanent magnet 8 magnetic part 27, permanent magnet 9 reed contact 0 reed contact 1 reed contact Scraper elements Scraper element electrically conductive contacts Microswitch Microswitch Bridge section Light source, light-emitting element Light receiver, Phototransistor Conveyor belt Passages Counter Light reflection range, reflection range

Claims

claims A method of drying laundry by means of an air flow comprising a drum for receiving the laundry and a duct system for guiding the air flow, the duct system having a downstream side of the drum portion in which the air flow is guided in a falling direction and in which arranged a sieve for catching lint from the air flow and the sieve a movement exporting scrapers for stripping trapped lint, and a collecting space are associated with an opening for receiving stripped lint, d ad u rch nich net that in the course of said movement of the scraper (17) monitoring the achievement of at least one specific, fixed movement position. 2. Method according to claim 1, characterized in that when the at least one determined fixed movement position is reached by the scraper (17) a sensor signal is emitted. 3. The method of claim 1 or 2, d ad u rch eken nzei ch n et that in addition a proper placement of a lint collection container (19) is monitored in the collecting space. 4. The method as claimed in claim 3, wherein the proper housing of the lint collector in the collecting space is monitored by evaluating at least one sensor signal triggered by the relevant storage. 5. The method according to any one of claims 1 to 4, dad u rch geken nzeich net that upon detection of improper operation of the scraper (17) in the course of said monitoring, a message signal is issued. 6. Apparatus for carrying out the method according to one of claims 1 to 5, for drying laundry by means of an air flow, comprising a drum for receiving the laundry and a duct system for guiding the air flow, wherein the duct system has a downstream side of the drum portion, in which of the air Ström is guided in a descending direction and in which a sieve arranged to catch fluff from the air flow and the sieve a movement exporting scrapers for stripping trapped lint and a plenum are associated with an opening for receiving stripped lint, dadu rch geken characterized that a movement of the scraper (17) with respect to at least one specific fixed movement position by means of a sensor arrangement (25, 26, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40) can be monitored. 7. Device according to claim 6, characterized in that a proper housing of a lint collecting container (19) provided for collecting lint to be removed by the scraper (17) can be monitored in the collecting space. 8. The device according to claim 7, characterized in that the proper housing of the lint collector (19) in the collecting space can be monitored by means of a separate sensor arrangement (28, 25, 27, 29, 36) , 9. Device according to one of claims 6 to 8, dad u rch gekennzeich net, that the respective sensor arrangement by a tactile or non-contact sensor (32, 33, 3435, 37, 38, 25, 26, 27, 28, 39, 40, 42, 39, 40, 44) is formed. 10. The device according to claim 9, dad urch gekennzeich net, that as a tactile sensor, a switch or limit switch (33, 34, 35) or a piezoelectric element (32) is provided. 11. The device according to claim 9, dadu rch geken nzeich net that at least one Hall sensor (25, 26), a light barrier (39, 30, 42) or an inductive sensor are provided as non-contact sensors. 12. The apparatus of claim 11, dad u rch geken nzeich net that when using a Hall sensor (25) for monitoring the at least one specific fixed movement position of the scraper (17) on this a magnetic field releasing magnetic part (27) is mounted and that the Hall sensor (25) is arranged stationary relative to the relevant magnetic part (27). 13. Device according to claims 12 and 7, characterized in that with said one Hall sensor (25) for monitoring a certain fixed movement position, in particular an end position of the scraper (17) in addition a proper recording of the lint collector (19) in the Collecting space can be monitored by the fact that the lint collector (19) has a magnetic field releasing magnetic part (28) whose magnetic field also acts on the Hall sensor (25). 14. Domestic appliance, in particular washing or tumble dryer with a device according to one of claims 6 to 13.