EP2113603A1 - Laundry drying device and method for operating a drying procedure for the laundry drying device - Google Patents

Abstract

The dryer (W) has a control unit (C) for controlling a drying process based on sensor data of a magnetic field sensor unit and a three dimensional hall sensor (31), which is arranged at the dryer in a fixed manner. The magnetic field sensor unit is arranged at a shaft stub at a rear wall of a laundry drum (2) of the dryer. A permanent magnet is arranged at the laundry drum. The magnetic field sensor unit is arranged to sense deflection of a drum shaft (23). A drum housing (1), in which the laundry drum is rotatably supported for receiving clothes (3). An independent claim is also included for a method for controlling a drying process.

Description

The invention relates to a laundry drying device, in particular washer-dryer, and a method for controlling a drying process of a laundry drying device, in particular washer-dryer.

Prior art washer-dryers show the documents WO 2007/138019 A1 such as EP 0 636 732 B1 . DE 44 27 361 A1 and DE 195 22 307 C2 , The three last-mentioned documents primarily each describe a washer-dryer which has a water-cooled condenser for drying wet laundry by means of a circulating process air stream.

A sensor unit comprising magnetic field sensors in a machine for washing and / or drying laundry emerges from US Pat WO 2007/118512 A1 , This sensor unit can also be referred to as a "magnetic field sensor unit". It serves to determine load-relevant parameters or imbalance parameters of a laundry drum. For this purpose, these parameters are detected by the sensor unit and fed to a control unit of the machine, where control or regulation parameters for the operation of the machine, in particular in a spin process, are derived from these parameters. The sensor unit can be designed such that it can detect load-relevant parameters in three dimensions. It can then be called a "3D sensor". A method for controlling a spin cycle in a washing machine and a correspondingly improved washing machine are apparent from the WO 2008 / 006675A1 ,

In a simple washer-dryer or tumble dryer, a drying period is set directly by a user. An advanced washer-dryer determines and automatically sets the duration of the drying cycle. In a pure tumble dryer, conductivity measurement on the laundry being dried is the most widely used process. Occasionally, temperature measurements are also used to determine the moisture content of the laundry. Also known is the use of an air humidity sensor for measuring the humidity of the process air exiting the drum. However, the use of such a humidity sensor is expensive, if only because the production of such a sensor is expensive.

A modern washing machine can in particular according to WO 2007/118512 A1 be equipped with a working according to a magnetic principle sensor unit to monitor the system movements during spin and thereby avoid attacks of the vibration system on the housing and overloading of the system by imbalance. In addition, such a sensor is used to carry out a weighing of the filled laundry after loading the washing machine, also to warn him against overcharging the machine and to issue recommendations for the amount of detergent to be dispensed. The operating principle is that the suspension system suspended on springs changes its position as a function of the charged load. It sinks down by gravity. The degree of system lowering is a measure of the amount of filled laundry. The designed as a 3D sensor sensor unit detects this movement and the controller calculates from this with the help of the spring constant of the suspension, the load. The 3D sensor, which operates as a load sensor in this way, is mounted in the upper area on the rear wall of the oscillating system and designed as a 3D Hall sensor. On the movably suspended part of the oscillating system, a permanent magnet is attached. The 3D Hall sensor measures the direction and field strength of the magnetic field caused by the permanent magnet. The pairing of these values is clearly attributable to a relative position to the permanent magnet. As a result, the position of the magnet relative to the Hall sensor can be determined.

Also, to determine a loading weight of a washing machine, a one-dimensional displacement sensor is known, which is housed in a vibration damper and can also be used for said weighing.

It is the object of the present invention to provide a possibility for inexpensive and relatively inexpensive laundry moisture-dependent control of a drying process, in particular for determining a duration of the drying process.

This object is achieved according to the features of the respective independent claim. Preferred embodiments are in particular the dependent claims.

The object can be achieved by means of a method for controlling a drying process of a laundry drying apparatus equipped with a loading sensor, the method comprising at least the step of detecting a loading weight (a Weighing) by means of the loading sensor and the step and a determination of a moisture measure from the detected load weight.

In particular, a moisture quantity and / or a moisture or a moisture level can be understood as a moisture measure.

According to one embodiment, it may be preferred that the step of determining the moisture measure comprises at least the following sub-steps: (i) detecting a, in particular maximum, spin speed during a washing cycle preceding the drying process and from this determination of a residual moisture (only in the case of an embodiment of the laundry drying appliance) Washer-dryer) and (ii) determining an amount of moisture from the residual moisture and load weight.

The relationship between the achievable residual moisture as a function of the spin speed is typically dependent on device-specific parameters (eg construction, speed curve during spin, esp. Spin time) and is therefore preferably determined experimentally for each device type. The maximum spin speed has the greatest influence on the residual moisture achieved. It is preferably redetermined in each washing process, since it can be influenced by user settings or the occurrence of unbalance-dependent reductions in spin speed.

It may be preferred if the determination of the residual moisture from the spin speed includes calculating the residual moisture from a corresponding calculation function with the spin speed as a calculation parameter.

It may be preferred if the determination of the residual moisture comprises determining the residual moisture from the spin speed by means of a corresponding value table.

It is also preferred that the method further comprises the step of determining a time duration required for the drying process from the predetermined amount of moisture and a known drying rate.

It is preferred to account for changes in process variables when the method includes the step of determining an amount of energy required for the drying process from the previously determined amount of moisture and a known device effectiveness index.

Then, it is particularly preferable if the method further comprises the step of determining a time duration required for the drying process from the previously determined amount of energy and determining a cumulative amount of energy introduced into the process by a heater.

However, it may also be preferred if the method further comprises the step of determining a time duration required for the drying process from the previously determined amount of moisture and a weight decrease of the laundry measured by means of the loading sensor.

It is then preferred if the measurement of a weight of the laundry in the Reversierpausen when the laundry drum is stopped or when rotating the drum and calculating the average over several drum revolutions, z. B. as already stated above, especially if immediately before the detection of the load weight (before weighing) the accumulated condensation in the drum area is removed by the pumping device.

According to an embodiment, it may be preferred that the step of determining the moisture measure comprises at least the following sub-steps: (i) detecting a loading weight by means of the loading sensor, (ii) monitoring a decrease in the loading weight per unit time and (iii) determining a residual moisture, in particular one Residual moisture content of about 15%, from a reduction in the decrease in the loading weight per unit time.

From the predetermined residual moisture level, in particular of about 15%, then the drying process z. B. be continued by another method, for. B. as described above or z. On the basis of a conductance. Preferably, this time of reaching the predetermined residual moisture level is used directly to switch to the cooling phase, if the laundry should be slightly moist at the end (8-10%), eg for ironing ("ironing"). If a dryer laundry is desired, then a time-controlled further drying section will preferably follow, the duration of which may be constant or dependent on the time required up to that point in time (eg large load - long time up to 15% - long dry time; Loading - short time up to 15% - short drying time).

In general, the weighing can be carried out with the washing drum stopped, for example before the start of a drum rotation or during a reversing of the drum.

However, it is preferable to avoid an influence of stiction in a vibration damper when the weighing is performed on a rotating laundry drum.

For this purpose, the loading weight is advantageously measured by the loading sensor several times (i.e., at least twice) in succession and then averaged. Preferably, a time period of the chronologically successive sensing (measuring period) is a multiple of a time required for one revolution of the laundry drum, since the influence of a laundry-related imbalance in the drum is thus reduced.

The object is also achieved by means of a laundry drying device. The laundry drying apparatus, in particular a washer-dryer or a pure clothes dryer, is equipped with a loading sensor and a control unit for controlling a drying process, the control unit being adapted to carry out a method as described above.

The laundry drying device or its control unit can then control the drying process on the basis of sensor data of the loading sensor, in particular a magnetic field sensor unit, in particular a 3D sensor. The signal of the loading sensor is thus optionally used in addition to the known functions for monitoring and controlling the drying process. In this case, different measured values can be obtained and control information derived.

By using the signals of a 3D sensor known for monitoring the spin process in a washing machine now also for controlling a drying process, even a pure tumble dryer, in particular a directly dependent on the humidity of the laundry to be dried control especially for a washer-dryer without additional Realize sensor technology. Corresponding measurements can also be combined with other measuring methods (conductance measurement, temperature measurement) in order to increase the detection accuracy of the data of the laundry to be dried and to achieve the desired Endrestfeuchten each with improved accuracy as the goals of a drying process.

The loading sensor may be any type of loading sensor, e.g. B. a one-dimensional displacement sensor. However, it is preferred if the loading sensor comprises a magnetic field sensor unit, in particular a Hall sensor. The magnetic field sensor unit is flexible and can be used without major modifications and also wear-resistant and accurate.

It is preferred for particularly simple attachment, when the loading sensor comprises a Hall sensor, which is stationarily arranged on the laundry drying device, for. B. rearward to the laundry drum, in particular on a rear wall of the laundry drying apparatus, and a permanent magnet which is arranged on the laundry drum.

It may also be preferred if the magnetic field sensor unit is arranged and arranged to sense a deflection of a drum shaft.

Also for use on a simple clothes dryer according to the invention, the use of a magnetic field sensor unit is taught. Since there is usually no problem with imbalances as in a washing machine in the case of a spin process on a simple clothes dryer, the storage of a laundry drum in a tumble dryer is easier and without a complex oscillating system executable. In general, the laundry drum of a tumble dryer is mounted on a stub shaft on a rear wall of the laundry drum and additionally supported by rollers which run on a flanged edge of the filling opening of the laundry drum. In this case, a magnetic field sensor unit - in particular in a comparison with a 3D sensor simplified version - attached to the stub shaft and used for weighing the laundry item.

FIG 1

zeigt als Schnittdarstellung in Querschnittsansicht eine als Frontladerwaschmaschine ausgebildete Maschine zum Waschen und / oder Trocknen von Wäsche;

FIG 2

zeigt ein Ablaufdiagramm zur Bestimmung einer Trocknungsdauer gemäß einer ersten Ausführungsform;

FIG 3

zeigt ein Ablaufdiagramm zur Bestimmung einer Trocknungsdauer gemäß einer zweiten Ausführungsform;

FIG 4

zeigt ein Ablaufdiagramm zur Bestimmung einer Trocknungsdauer gemäß einer dritten Ausführungsform;

FIG 5

zeigt ein Ablaufdiagramm zur Bestimmung einer Trocknungsdauer gemäß einer vierten Ausführungsform;

FIG 6

zeigt eine schematische Schnittansicht durch die als Frontladerwaschmaschine ausgebildete Maschine zum Waschen und / oder Trocknen von Wäsche aus FIG 1 mit der über eine Trommelwelle angetriebene Wäschetrommel und mit einer im Bereich einer Lageranordnung der Trommelwelle angeordneten Magnetfeldsensoreinheit zur Ermittlung von belastungsrelevanten Kenngrößen bzw. einer Unwucht der Wäschetrommel bzw. der Trommelwelle;

FIG 7

zeigt eine weitere schematische Schnittansicht durch die Maschine gemäß FIG 6, wobei die Durchbiegung der Trommelwelle schematisch angedeutet ist, welche durch die gemeinsame, schwerkraftbedingte Gewichtskraft der Wäschetrommel und des Waschguts einerseits und der durch die Riemenspannung des Antriebsriemens erzeugten Riemenspannkraft andererseits erzeugt wird;

FIG 8

zeigt eine schematische Vorderansicht auf die Wäschetrommel der Maschine zum Waschen und / oder Trocknen von Wäsche gemäß den FIG 6 und 7, wobei die schematische Wirkung der Schwerkraft auf eine am Außenumfang der Wäschetrommel befindliche, durch die Ungleichverteilung des Waschguts hervorgerufene Masse schematisch angedeutet ist; und

FIG 9

zeigt eine schematische Vorderansicht auf die Wäschetrommel sowie eine schematische Schnittansicht durch die Maschine zum Waschen und/oder Trocknen von Wäsche gemäß den FIG 6 bis 8, wobei die Wirkung einer am Außenumfang der Wäschetrommel wirkenden, durch eine Unwuchtmasse hervorgerufenen Fliehkraft während eines dynamischen Waschprozesses schematisch angedeutet ist.

In the following figures, the invention will be described schematically with reference to exemplary embodiments. It can be provided with the same reference numerals for better clarity identical or equivalent elements.

FIG. 1

shows a sectional view in cross-sectional view designed as a front loader washing machine for washing and / or drying of laundry;

FIG. 2

shows a flowchart for determining a drying time according to a first embodiment;

FIG. 3

shows a flowchart for determining a drying time according to a second embodiment;

FIG. 4

shows a flowchart for determining a drying time according to a third embodiment;

FIG. 5

shows a flowchart for determining a drying time according to a fourth embodiment;

FIG. 6

shows a schematic sectional view through the machine designed as a front loader washing machine for washing and / or drying of laundry FIG. 1 with the laundry drum driven via a drum shaft and with a magnetic field sensor unit arranged in the region of a bearing arrangement of the drum shaft for determining load-relevant parameters or an imbalance of the laundry drum or drum shaft;

FIG. 7

shows a further schematic sectional view through the machine according to FIG. 6 wherein the deflection of the drum shaft is schematically indicated, which is generated by the common, gravitational weight of the laundry drum and the laundry on the one hand and the belt tension force generated by the belt tension of the drive belt on the other hand;

FIG. 8

shows a schematic front view of the laundry drum of the machine for washing and / or drying of laundry according to the FIG. 6 and 7 , wherein the schematic effect of gravity on a located on the outer circumference of the laundry drum, caused by the unequal distribution of the laundry mass is indicated schematically; and

FIG. 9

shows a schematic front view of the laundry drum and a schematic sectional view through the machine for washing and / or drying laundry according to the FIGS. 6 to 8 wherein the effect of acting on the outer circumference of the laundry drum, by an imbalance mass caused centrifugal force during a dynamic washing process is indicated schematically.

FIG. 1 shows components of a designed as a front load washer dryer W with air condensation cooling, which is in the state after a wash and before a drying cycle. The washer-dryer has a drum housing or tub 1, in which a laundry drum 2 (inner drum) for receiving laundry 3 is rotatably mounted. By means of a fresh water supply line 4, which opens into a dispenser 5, water with or without detergent additive to the drum housing 1 (outer drum, tub) supplied and forms there the free fleet 6. The aufwärmbare a heater 7 free liquor 6 can by means of a drain pump 8 by a drain channel 9 are discharged to the outside.

In addition, a circulating air or process air duct 10 for the process air is connected to the tub 1. The upper part 11 of the process air duct 10 is connected to the pressure side of a process air blower 12 and opens at its other end in the drum housing 1 above the filling opening (not shown here) of the laundry drum 2. The lower part 13 of the process air duct 10 is to the suction side of the process air blower 12 connected and opens in a lower portion in the drum housing 1. This orifice 14 is still above the level that is ever reached by the liquor during washing or rinsing. In the upper channel part 11, a heating device, not shown here, is typically also arranged for heating the process air. In the drying operation, the process air is blown by the fan 12 through the heater, heated there and then mixed in the laundry drum with the wet laundry. There, the heat energy is used to evaporate the water in the laundry. The air is then cooled in a condenser 15 and returned to the blower 12.

For this purpose, the condensation device 15 designed as a heat exchanger, which essentially has a cooler 16, is mounted in a lower part 13 of the process air channel 10. The cooler is cooled by fresh air, which is sucked from the environment of the washer dryer W by a cooling air blower 17 and fed to the cooler 16 via the cooling air inflow channel 18. After flowing through the radiator 16 and receiving heat energy from the process air, the cooling air is conducted via a cooling air outflow channel 19 to an exhaust air outlet 20. When cooling the process air in the condenser resulting condensate is discharged via a downpipe 21 from the radiator housing to the drum housing 1 and from there by means of a pumping device for the dirty water from time to time pumped into the sewage system. The downpipe 21 is designed here as part of the process air duct 10. During drying, therefore, there is a transport of water from the laundry 3 located in the drum 2 to the outside. This reduces the weight of the laundry 3 and thus also the force on the vibrating system. The programs of the washer-dryer W are controlled by means of a control unit C.

The washer-dryer W is further equipped with a magnetic load sensor 31 fixed at the rear, which is designed as a 3D Hall sensor, while a non-illustrated permanent magnet is attached to the movably suspended oscillating system. As is known in principle, the 3D Hall sensor 31 measures a magnetic field direction and a magnetic field strength. The pairing of these values is clearly attributable to a relative position to the permanent magnet. As a result, the position of the magnet with respect to the Hall sensor 311 can be determined, and thus the loading weight.

In the case of a pure tumble dryer, the only required for washing the laundry 3 elements, such as fresh water supply line 4 and 5 Einspülschale, not available.

FIG. 2 shows a flowchart for device-side determination of a drying time from a determination of the amount of water to be evaporated.

In this process, a loading of the machine with a laundry item to be dried is first carried out in a step S10.

This is followed in a step S11 by a weighing of the inserted laundry item, ie, that a loading weight of the laundry item is detected, by means of the loading sensor. This can be done in a variant in the state standing internal drum. In a further, alternative or additional variant, the weighing takes place with the inner drum rotating. As the drum rotates, multiple readings are taken over a predetermined period of time and then averaged. By averaging the measured values, the problem of possible static friction in the vibration dampers, to which, among other things, the tub is suspended, can be overcome. The predetermined period of time is preferably a multiple of the time required for a drum rotation. The determined weight is the sum of dry laundry and the water contained in the laundry.

In a subsequent step S12, a maximum spin speed achieved at the last preceding spin cycle (eg following the previous wash cycle) is reduced to the residual moisture reached during the last spin cycle, ie. the relative proportion of remaining in the wash water, closed. It is assumed that this batch of laundry, or part of it, should be dried.

The inference to the residual moisture from the spin speed is based on previously determined empirical values or preliminary tests. A correlation between spin speed and residual moisture can be done by means of a correspondingly formulated calculation function or a table with known value pairs of spin speed and time (characteristic).

In step S12 or a subsequent step S13, the amount of water to be removed is determined from the residual moisture and the known loading weight. If, furthermore, the drying rate in g of water removed per minute (which need not be constant) is taken into account, this will be used to calculate a period of time required for drying and then to control the drying program.

However, the drying rate may be variable due to external influences. So z. B. in an air condensation dryer, the condensation performance and thus the drying rate are influenced by the temperature in the installation room. A better control parameter is therefore the amount of energy spent in drying.

FIG. 3 shows a further flow chart for determining a device-side drying time from a determination of the amount of water to be evaporated.

In contrast to the expiration of FIG. 2 Now, after step S12, a step S21 of a determination of the amount of energy required for the drying follows. In this case, in the case of a known amount of water to be removed (step 12) and using the amount of energy known per device series, which is to be expended per g of water to be removed (device efficiency index Wh), the amount of energy required for the drying is calculated.

To determine the duration of the drying process in S22 now only needs during the drying program by monitoring the switching state of the heater using the known heating power of the heater to be summed up the amount of energy introduced by the heater in the process and compared with the pre-calculated amount of energy. Upon reaching the pre-calculated amount of energy, the drying process is terminated. The determination of the duration is thus not done at the beginning of a drying process, but is determined during the drying process in a timely manner. As a result, changes in the process parameters, such as a change in the ambient temperature, etc., are taken into account.

FIG. 4 shows a flowchart for determining a device-side drying time by measuring the amount of water removed. After step S12, in which now the weight of the dried laundry is calculated, in step S31 a new weighing is carried out regularly by means of the loading sensor, and indeed, as already described for step S11, standing in the state internal drum during a Reversierpause and / or at rotating inner drum. Subsequently, in step S32, the previously measured loading weight is compared with the weight of the dried laundry calculated in step S12. If the measured loading weight has decreased so far that it has reached the weight of the dried laundry, the drying process is terminated.

In order to prevent a measurement error due to condensed water collected in the drum system, the accumulated condensation water is removed by the pump-down device in step S33 immediately before weighing. For such a weighing, therefore, a synchronization of the sub-processes drum reversion, pumping down and measured value detection must be carried out.

FIG. 5 shows a flow chart for determining a device-side drying time by measuring the temporal change (the gradient) of the removed amount of water. In this process, no knowledge about a residual moisture of the invited laundry item is needed.

After the start of the program, the system waits until the system has heated up and a relatively constant process state is established (step 41). This initially leads to a constant drying rate, which is essentially limited by the dryer performance, and thus to a time uniform weight reduction. At the end of drying, the evaporation rate and thus also the amount of condensate per unit of time decrease. This allows a conclusion on the residual moisture of the laundry: in cotton textiles z. B. at about 15% residual moisture of the laundry water present on the surface of the fibers evaporates. The vaporization of the capillary water stored in the fibers takes more time and energy. The drying process slows down. This reduction of the condensate flow (the amount of condensate removed per unit of time) is thus an indicator of the attainment of a residual moisture content of about 15%. This is evident in a reduction in the gradient of the weight curve or a reduction in the gradient of weight reduction.

In the illustrated sequence, a weighing is performed at regular intervals in step 42. In step S43, a reduction in the weight reduction per unit time or the gradient of the weight reduction is observed. If the weight reduction per unit of time or the gradient of the weight reduction falls below a certain threshold value - relative or absolute - then the attainment of a residual moisture content of about 15% can be recognized and responded to on the control side. The weighing in step S42 is preferably done after the step of pumping out the accumulated water in step S44. In the FIG. 5 sketched method is suitable for both pure dryers and washer-dryers. When using a pure tumble dryer it is equipped with a loading sensor, eg. B. a 3D loading sensor whose attachment is particularly simple.

FIG. 6 shows in a sectional view of the tub or the drum housing 1, in which the laundry drum 2 is mounted on one side via a bearing assembly 22. The laundry drum 2 is connected via a drum shaft 23 with a pulley 24, which transmits the torque of a drive unit to the drum shaft 23 of the laundry drum 2 via a drive belt, not shown. The drum shaft 23 is held by two bearings 25 of the bearing assembly 22, which in turn are received within a bearing housing 26 at a distance from each other. In the present embodiment, the bearings 25 are formed as ball bearings. The bearing housing 26 is in turn firmly connected to the rear wall of the tub 1.

In a central region between the two bearings 25, a magnetic field sensor unit 30 is accommodated within the bearing housing 26, which comprises one or a plurality of magnetic field sensors. In addition to the preferred arrangement of the magnetic field sensor unit 30 provided here in the middle between the two bearings 25, it would of course also be conceivable to arrange them closer to one of the two bearings 25. The magnetic field sensor unit 30 detects the magnetic field of a magnetized area 27 moved with the drum shaft 23, this in turn being arranged in the area of the magnetic field sensor unit 30. In the present embodiment, this is the Drum shaft 23 itself at least partially made of a material with corresponding magnetic or magnetostrictive properties. However, in the context of the invention as encompassed with it is to be considered that a drum shaft 23 may be used, for example, even has no or only insufficient magnetic properties and includes a co-moving component, for example in the form of an externally arranged sleeve, which force, for example - And / or positively connected to the drum shaft 23. The magnetized portion 27 of the drum shaft 23 is preferably made of a ferromagnetic material having a high magnetostriction constant, for example, Steel No. 1.4057, so that an inexpensive magnetic field sensor unit 30 having a relatively low sensitivity can be used. Due to the magnetostrictive properties of the magnetized portion 27 moving with the drum shaft 23, the mechanical deformation of the drum shaft 23 is transformed into a change of the magnetic field formed by the magnetized portion 27. This change in the magnetic field is detected contactlessly by the magnetic field sensor unit 30.

und andererseits durch das Biegemoment M_R der Riemenspannkraft F_R über den Hebelarm I_r des an der Riemenscheibe 24 angeordneten Antriebsriemens nach der Gleichung $${\mathrm{M}}_{\mathrm{R}}\mathrm{=}{\mathrm{F}}_{\mathrm{R}}\mathrm{*}{\mathrm{I}}_{\mathrm{r}}$$

erzeugt. Die Wirkungsrichtungen der Riemenspannkraft und der durch die Gravitationskraft erzeugten Gewichtskräfte sind in diesem Beispiel vereinfachend als parallel angenommen. Da die Riemenspannkraft F_R des Antriebsriemens, die Gewichtskraft der Wäschetrommel F_T und die Hebelarme I_t und I_r für ein Gerät als konstant angesehen werden können, ist bei stehender Waschtrommel 2 die mit der Biegelinie 28 dargestellte Durchbiegung bzw. Biegespannung der Trommelwelle 23 nur noch von der Gewichtskraft F_W des in der Wäschetrommel 2 vorhandenen Waschguts abhängig. Die Richtung dieser Biegespannung ist konstant und unabhängig von der Drehwinkelstellung der Wäschetrommel 2. FIG. 7 shows in a further sectional view through the front loader washing machine according to FIG. 6 The deflection of the drum shaft 23 shown with the bending line 28 is schematically shown. The deflection is on the one hand by the bending moment M _{T of} the jointly acting weight forces F _{T of} the laundry drum 2 and F _{w of} the laundry on the lever arm I _t according to the equation $${\mathrm{M}}_{\mathrm{T}}\mathrm{=}\left({\mathrm{F}}_{\mathrm{T}}\mathrm{+}{\mathrm{F}}_{\mathrm{w}}\right)\mathrm{*}{\mathrm{I}}_{\mathrm{t}}$$

and on the other hand by the bending moment M _{R of} the belt tension F _R on the lever arm I _r of the arranged on the pulley 24 drive belt according to the equation $${\mathrm{M}}_{\mathrm{R}}\mathrm{=}{\mathrm{F}}_{\mathrm{R}}\mathrm{*}{\mathrm{I}}_{\mathrm{r}}$$

generated. The directions of action of the belt tensioning force and the weight forces generated by the gravitational force are assumed to be parallel in this example for simplicity. Since the belt tension F _{R of} the drive belt, the weight of the laundry drum F _T and the lever arms I _t and I _r can be considered as constant for a device, with standing washing drum 2, the deflection or bending stress of the drum shaft 23 shown with the bending line 28 only still dependent on the weight F _{W of} the present in the laundry drum 2 laundry. The direction of this Bending stress is constant and independent of the rotational angle position of the laundry drum. 2

An exact determination of the weight of the laundry is thus possible in a simple manner on the basis of the bending line 28 shown bending or bending stress of the drum shaft 23. The central arrangement of the magnetic field sensor unit 30 in the area of the maximum load or deflection of the drum shaft 23 and the correspondingly large changes in the magnetic field formed by the magnetized area due to the effect of the inverse magnetostriction thereby allow easy detectability by the magnetic field sensor unit 30. Accordingly, the use is less sensitive and therefore cost magnetic field sensors possible, whereby the relevant parameter for the treatment of imbalance effects - the torque, the torsional moment, the bending force, the mass of the laundry and the rotation angle of the laundry drum 2 - can be detected without contact and wear.

FIG. 8 shows a schematic front view of the laundry drum 2 of the machine for washing and / or drying of laundry according to the FIG. 6 and 7 , The following explains how torques can be determined which are transmitted from the pulley 24 via the drum shaft 23 to the laundry drum:

The driving torque, which is introduced via the pulley 24 in the drum shaft, while the following torques are opposite: moments of inertia during acceleration or deceleration of the rotary motion of the laundry drum 2, friction moments due to friction in the bearings 25 and between the laundry drum 2 and the surrounding air or Washing liquid, as well as with the rotation of the drum changing torques due to the acceleration of the washing drum located on the outer circumference of the laundry drum 2.

In FIG. 8 For this purpose, the unbalanced, acting on the outer circumference 29 of the rotating with a certain speed drum 2 weight F _{ug is} shown. Upon rotation of the laundry drum 2 with a certain speed or angular velocity ω above the application speed of the laundry can be formed by uneven mass distribution with the mass m _u a resulting imbalance. The application speed is to be understood as the speed at which a force acting on the laundry centrifugal force is equal to or greater than acting on the laundry gravity, so that the laundry is immobilized on the inner wall of the laundry drum. The imbalance mass m _u with the weight F _ug must be during a complete Rotation of the laundry drum 2 are raised in the upward movement against gravity. In the downward course of the rotation of the laundry drum 2, however, it is accelerated by gravity. Due to the cyclically changing lever arm h _t , a sinusoidal torque curve M _ug is produced on the drum shaft 23, which results in a torsional voltage changing with the drum shaft rotational speed or angular velocity ω whose amplitude depends on the magnitude of the resulting imbalance. Thus, the following equation results for the torque curve M _ug : $${\mathrm{M}}_{\mathrm{ug}}\mathrm{=}{\mathrm{F}}_{\mathrm{ug}}\mathrm{*}{\mathrm{H}}_{\mathrm{t}}\mathrm{*}\sin \left(\mathrm{.omega.t}\right)$$

Therefore, the position and size of the imbalance in the washing drum 2 can be determined exactly by the evaluation of the determined load-relevant parameters. By deriving appropriate control and / or regulation parameters, a targeted intervention in the washing process to reduce or even completely eliminate the imbalance effect is possible.

Finally, in FIG. 9 in a schematic front view of the laundry drum 2 and a schematic sectional view through the machine according to the Fig. 6 to 8 another load case of the washing machine and the recoverable parameter values or load-relevant parameters shown. In this case, in particular, a bending moment M _{UF can be determined} on the basis of a centrifugal force of the imbalance mass m _u acting on the outer circumference 29 of the washing drum 2. If, during a spin process with the drum shaft speed or angular velocity ω above the application speed of the laundry, an imbalance develops due to a mass misalignment, this generates a centrifugal force F _UF acting on the outer circumference 29 (radius r _t ) of the wash drum 2. This centrifugal force F _UF is formed by the equation: $${\mathrm{M}}_{\mathrm{UF}}\mathrm{=}{\mathrm{m}}_{\mathrm{u}}\mathrm{*}{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0001.png,imgf0006.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^{\mathrm{2}}\mathrm{*}{\mathrm{r}}_{\mathrm{t}}$$

This centrifugal force F _UF generates a bending moment M _UF via the lever arm I _u , which in turn causes a bending stress in the drum shaft 23. Since the direction of this voltage is constant with respect to the magnetized drum shaft 23, but rotates at the drum shaft speed ω, the magnetic field sensor unit 30 detects a signal circulating at the drum shaft speed ω, which depends on the size of the mass distribution error and axial position on the outer circumference 29 of the washing drum 2 depends. The bending moment M _UF is the cause of the actual drum shaft load.

On the basis of the load-relevant parameters or unbalance parameters determined by the magnetic field sensor unit 30, control and / or control parameters of the machine can be derived as a function of the determined values in a subsequent method step. The derivation of the control and / or regulation parameters of the machine takes place by means of a control device of the machine which is present anyway and which is present in any case. By way of the control device, which is connected to the drive of the machine, it is possible, for example, to change the rotational speed or the angular speed of the laundry drum as a function of the control and / or regulation parameters and thus to reduce or completely eliminate an imbalance due to an uneven distribution of the laundry , For this purpose, it is conceivable, for example, to change the rotational speed or the angular velocity of the laundry drum 2 abruptly and possibly only for a short period of time, which allows a more uniform distribution of the laundry to be realized.

In particular, from the characteristics of the magnetic field sensor unit 30, the weight F _{w of} the laundry can be determined and used to control the drying process, as already detailed by way of example with respect to FIG 1 to 5 described.

Of course, the present invention is not limited to the embodiments shown.

Thus, the processes and sub-processes shown in the above embodiments can be applied individually or combined to achieve higher reliability. These processes can also be combined with other methods for controlling a drying process, for. B. based on a conductivity measurement or temperature measurements. For example, the processes, in particular the process can be FIG. 5 , be combined with a determination of the drying progress, in particular the residual moisture, from the performance of the process air / cooling air heat exchanger. These processes can also be used for certain areas of the residual moisture or drying time and can be supplemented or replaced by other processes in sections. The degree of drying to be achieved can be chosen variably, z. B. ironed, cupboard dry, etc. and may depend on a selected textile.

In particular, the loading sensor can also be used in a pure tumble dryer, in particular to determine the drying process. It can be as in the above FIGS. 6 to 9 described loading sensor can be used, or any another load sensor, z. B. a one-dimensional displacement sensor. In this case, the invention makes use of the fact that the laundry introduced into the laundry drum of the tumble dryer loads and shifts the laundry drum and / or exerts a measurable bending moment on the drum shaft driving the laundry drum.

LIST OF REFERENCE NUMBERS

• 1 drum housing
• 2 laundry drum
• 3 laundry
• 4 fresh water supply
• 5 induction bowl
• 6 free fleet
• 7 heating
• 8 lye pump
• 9 drainage channel
• 10 process air duct
• 11 upper part of the process air duct
• 12 process air blowers
• 13 lower part of the process air duct
• 14 estuary
• 15 condensation device
• 16 coolers
• 17 cooling air blower
• 18 Cooling air inlet channel
• 19 Cooling air outlet channel
• 20 exhaust air outlet
• 21 downpipe
• 22 bearing arrangement
• 23 drum shaft
• 24 pulley
• 25 bearings
• 26 bearing housing
• 27 magnetized area
• 28 bending line
• 29 outer circumference
• 30 magnetic field sensor unit
• C control unit
• F _R Belt tension
• F _T Weight of the laundry drum
• F _UF centrifugal force
• F _ug weight
• F _w weight of the laundry
• I _t lever arm
• I _r lever
• I _u lever arm
• M _R bending moment
• M _UF bending moment
• M _ug torque curve
• r _t radius of the laundry drum
• S10-S54 process steps
• W tumble dryer
• ω angular velocity

Claims (15)

Method for controlling a drying process of a laundry drying device (W) equipped with a loading sensor (30; 31), characterized in that the method comprises at least the following steps: - Detecting a loading weight (F _W ) by means of the loading sensor (30; 31) (S11) and - Determining a moisture measure from the detected load weight (F _W ). A method according to claim 1, characterized in that the step of determining the moisture measure comprises at least the following sub-steps: - Detecting a, in particular maximum, spin speed during a preceding the drying process wash cycle and therefrom determining a residual moisture and - Determining an amount of moisture from the residual moisture and the loading weight (F _W ) (S12). A method according to claim 2, characterized in that the method further comprises the following step: Determining a time required for the drying process from the previously determined amount of moisture and a known drying rate (S13). Method according to one of claims 2 or 3, characterized in that the method further comprises the following steps: Determining a quantity of energy required for the drying process from the previously determined amount of moisture and a known device effectiveness index (S21); - Determining a time required for the drying process time from the previously determined amount of energy and determining a by a heater (7) introduced into the process cumulative amount of energy (S22). Method according to one of claims 2 to 4, characterized in that the method further comprises the following step: - Determining a time required for the drying process time from the previously determined amount of moisture and a by means of the load sensor (30) measured weight loss of the laundry (S31, S32). A method according to claim 5, characterized in that immediately before the detection of the loading weight (F _W ) accumulated condensate is removed by the pumping device (8) (S33, S44). Method according to one of the preceding claims, characterized in that the step of determining the moisture measure comprises at least the following sub-steps: Detecting a loading weight (F _W ) by means of the loading sensor (S11), - monitoring a decrease in the loading weight (F _W ) per unit time (S42); and - Determining a residual moisture, in particular a residual moisture content of about 15%, from a reduction in the decrease of the load weight (F _W ) per unit time (S43). Method according to one of the preceding claims, characterized in that the step of detecting the loading weight (F _W ) by means of the loading sensor (S11) in a standing laundry drum (2) is performed. Method according to one of claims 1 to 7, characterized in that the step of detecting the loading weight (F _W ) by means of the loading sensor (S11) in a rotating laundry drum (2) is performed, wherein the detection of the loading weight (S11) a temporally successive sensing and subsequent averaging of a plurality of load weight measurements (F _W ). A method according to claim 9, characterized in that a period of time successive sensing of the plurality of measured values is a multiple of a time required for one revolution of the laundry drum (2). A laundry drying apparatus (W) comprising a control unit (C) for controlling a drying operation and a loading sensor (30; 31), characterized in that the control unit (C) is adapted to carry out a method comprising at least the following steps: - Detecting a loading weight (F _W ) by means of the loading sensor (30; 31) (S11) and - Determining a moisture measure from the detected load weight (F _W ). Laundry drying apparatus (W) according to claim 11, characterized in that the loading sensor comprises a Hall sensor (31) which is arranged stationarily on the laundry drying apparatus (W), and a permanent magnet which is arranged on the laundry drum (2). Laundry drying apparatus (W) according to claim 11, characterized in that the loading sensor comprises a magnetic field sensor unit (30; 31), in particular a Hall sensor (31), wherein the magnetic field sensor unit (30) is arranged and arranged to deflect a drum shaft (23). sense. Laundry drying apparatus (W) according to any one of claims 11 to 13, characterized in that the laundry drying device (W) is a clothes dryer. Laundry drying apparatus (W) according to any one of claims 12 or 13 in combination with claim 14, characterized in that the magnetic field sensor unit (30) is arranged on a stub shaft on a rear wall of a laundry drum of the clothes dryer.

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