EP1734167A1

EP1734167A1 - Method for wetting laundry and washing machine

Info

Publication number: EP1734167A1
Application number: EP05013071A
Authority: EP
Inventors: Roland Siedentopf; Hildegard Kraft; Dieter Schmidt; Michael Wolf
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2005-06-17
Filing date: 2005-06-17
Publication date: 2006-12-20
Anticipated expiration: 2025-06-17
Also published as: DE602005002642D1; ATE374273T1; DE602005002642T2; ES2293424T3; PL1734167T3; EP1734167B1

Abstract

The invention relates to a method for wetting laundry in a washing machine having a washing drum, the method comprising the steps of starting (100) a wetting program sequence; monitoring (112) at least one physical value related to the rotation of the washing drum and/or detecting (114) the weight of the laundry loaded in the washing drum; and modifying (132-140) the wetting program sequence in dependency of the at least one monitored physical value and/or the laundry weight. A washing machine is provided with a control unit adapted to modify a wetting sequence in dependency of detected physical value and/or weight signals.

Description

The present invention relates to a method for wetting the laundry loaded into a washing drum of a washing machine and a washing machine controlling the wetting process.
For a conventional washing machine it is normally recommended to use the maximum load capacity for laundry to be loaded into the washing drum due to environmental and budgetary considerations. Depending on the type of fabrics, the volume of dry laundry may vary considerably. For example 6 kg of toweling.have much more volume than 6 kg of jeans trousers. Thus, voluminous but low weight laundry is sometimes compressed into the drum and the porthole door is closed with force. Especially in the start phase excessive friction may occur between the compressed laundry and the porthole door and in particular between the laundry and the rubber gasket. This may result in increased wear of the gasket and in an overload of the motor driving the drum, which may affect the washing machine's lifetime. Also the laundry within the drum could be damaged by excessive friction or by jamming the laundry between the drum and the gasket.
It is an object of the invention to provide a method for wetting laundry and a washing machine which provide an optimized wetting procedure.
The invention is defined in claims 1, 2 and 12, respectively.
Particular embodiments are set out in the depended claims.
According to claim 1, a method for wetting laundry in a washing machine is provided in which the wetting program sequence is monitored to detect whether the rotation conditions for rotating a washing drum are in an acceptable operating condition or not. If the monitoring results in the determination that there is any deviation from desired conditions, the wetting program sequence is modified.
In an alternate embodiment, a method for wetting laundry in a washing machine comprises the detection of or request for the weight of the laundry loaded in the washing drum. A laundry weight detector is provided in the washing machine or the user.of the washing machine can for example input the weight of the laundry at an input device of the washing machine. Then, in dependency of the laundry weight the wetting program sequence is modified.
In a standard wetting program sequence it is to be observed that the originally voluminous dry laundry shrinks in its volume by increasingly soaking the loaded laundry. In the completely soaked state, the laundry occupies much less volume within the drum than in the dry state. Therefore, in the soaked state it can be assumed that the laundry, which has initially to be compressed when closing the porthole door and which rubs during the first rotations of the drum against the door and the gasket, has a reduced volume and loosely contacts the door and the gasket.
The modification of the wetting program sequence in dependency of the at least one monitored physical value and/or in dependency of the laundry weight is in particular useful in the starting phase of the wetting program sequence when the laundry is still dry or only minimally wetted. By the modification the friction of the laundry is decreased by increasing the wetting degree of the laundry and/or adapting the rotation conditions of the drum.
According to a preferred embodiment, at least one drum rotation parameter and/or at least one parameter of the liquid supply to the washing drum are/is modified as compared to the standard wetting program sequence executed without modification.
In particular embodiments the drum rotation speed is modified, for example the drum rotation is lowered which results in a lower energy consumption for rotating the drum and at the same time to a lower wear of the gasket and the laundry when rubbing along the gasket or the door. Or the drum rotation is reversed, such that by reorientation of the laundry within the drum the friction is reduced. Also by a modification of the duration and/or start times of rotation intervals the twisting of the laundry within the drum is minimized. Also laundry portions which are wound between the drum and the gasket can be drawn back into the drum. Of course, one or more of these drum rotation modification parameters can be combined to any extent with one another to optimize the friction relief effect. Also the program rotation parameters can be combined with anyone of the liquid supply parameters as explained in the following.
According to a preferred embodiment, the at least one liquid supply parameter includes the liquid flow rate or the liquid total amount supplied into the washing tub. For example, the flow rate of fresh water taken from the house supply is increased to shorten the time up to a complete wetting of the laundry. Or the flow rate and flow time in the initial phase of the wetting program sequence is increased, such that a shrinking is obtained in the starting phase of the wetting program sequence. Another example is to modify the liquid supply intervals, for example when a high friction value as an physical value is detected, the rotation is stopped and a predefined amount of liquid is supplied into the washing tub before the further rotation is started for a very fast soaking process. Modification of the liquid supply parameter may also include changing the liquid supply channel for supplying the liquid to the laundry, for example the fresh water liquid maybe sprayed from a spray nozzle arranged at the porthole directly onto the laundry. Or a recirculation process can be started in which a circulation pump pumps the liquid from the bottom of the tub into the drum. Of course, all liquid supply parameters can be used as individual measure or in combination with a modification of the other parameters (liquid supply and rotation parameter) in an adjustable way.
It is also to be understood that the modification includes a timely varying modification, for example the modification can take place at the starting phase of the wetting program sequence, while at the end phase of the wetting program sequence the program returns to the standard wetting program sequence. It is also to be understood that the monitoring and the modification can take place once in the wetting program sequence, repeatedly during the wetting program sequence or continuously.
In an embodiment the monitored physical value related to the drum rotation is the torque for rotating the drum which is for example detected by a torque meter. Or the parameter is the rotation speed of the drum which can be taken for example by a tachometer connected to the drum or the motor or any other rotation sensor. Or the parameter is any parameter of the motor which is driving the drum. Of course, one or more of these parameters can be combined. Motor parameters include the motor current or power consumption, which are indirect measures for the drum friction, or a control value which is used in a feedback loop for controlling the drum rotation to have a predefined constant rotation speed.
In a preferred embodiment the monitored at least one physical value and/or laundry weight are processed and then the processing result is used for modifying the wetting program sequence. Such a processing includes comparing the detected or monitored physical value and/or the laundry weight with values in a look-up-table, which will result in a value or action to be taken for modifying the wetting program sequence. Or one or more of these parameters are input into a neural network or a fuzzy logic which are trained with optimum correction measures and output one or more parameters to be modified during the wetting program sequence. Or processing includes simple comparisons with threshold values to stepwise modify the wetting program sequence. Of course, all the processing may be done under consideration of the advance of the wetting program sequence, e.g. the degree of wetting already obtained, or any other time varying parameter. For example a modification is done only after an integration of the monitored value, such that peak deviations are averaged. A time variant processing is also done in that it is taken in consideration that the torque or power consumption is increased when the drum is accelerated from the stand to a predefined rotation speed. For example in a memory of a control unit of the washing machine time-dependent normal parameters are stored which are used to compare them to the current monitored physical value.
In another embodiment the complete washing program is terminated, if the monitored physical value and/or the laundry weight exceed/s a predefined value, in particular if the monitor physical value exceeds a predefined value for a predefined period or if it exceeds a critical value. In the latter case it can be detected that the counter measures to reduce the friction have little effect and it is decided to stop the washing machine to prevent serious damage to the laundry and/or the washing machine.
Reference is made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings, which show:

Fig. 1: a schematic block diagram of some units of a washing machine,
Fig. 2: a flow diagram for controlling a wetting program sequence of the washing machine shown in Fig. 1, and
Fig. 3a to 3d: the drum rotation speed and friction force in dependency of time in a standard wetting modus and in modified modi.

Fig. 1 shows a schematic overview of some elements of a washing machine 1. A washing drum 4 is arranged within a washing tub 2 wherein the drum 4 is rotated by a motor 6. A belt 8 connects a wheel on the shaft of the drum to a wheel on the shaft of the motor 6. The motor 6 is energized by a power controller 10 which controls the rotation speed of motor 6 in a feedback loop arrangement such that the actual rotation speed is adjusted to a presently predefined rotation speed. The value for the predefined rotation speed is sent from a control unit 16 controlling the operation of the washing machine 1 to the power controller 10. Due to the transmission ratio between the two shaft wheels of the drum 4 and motor 6 there is a fixed relation between the motor rotation speed and the drum rotation speed. Thereby the drum rotation is controlled in a known relation by controlling the motor. The power controller 10 sends a power consumption value to the control unit 16.
A further motor parameter is monitored by temperature sensor 12. The temperature sensor 12 sends a continuous temperature signal to the control unit 16 for further processing. The temperature sensor 12 works in addition to or in combination with the overload temperature sensor as it is normally provided for each motor to prevent temperature damage to the motor. The temperature sensor 12 senses temperature changes well below the temperature destruction threshold normally used for motors.
A weight sensor 14 is arranged within the washing machine 1 which detects the dry weight of the laundry stored in the drum 4 before supplying any liquid to the washing machine. In an alternate embodiment or in addition to detecting the dry weight of the laundry by weight sensor 14, the dry weight estimated by a user of the washing machine 1 is input by an input/monitor panel 18. Panel 18 is also used to select a washing program convenient for the laundry. Further, the input/monitor panel 18 is adapted to indicate selected parameters as well as the state of the washing program by acoustic and/or optical elements as for example an LCD monitor.
Fig. 1 shows a particular embodiment of a washing machine 1 in which a recirculation system is provided, comprising a recirculation pump 20 controlled by control unit 16 and a fluid line 22 connecting the recirculation pump 20 to a nozzle 23 being arranged adjacent to the porthole of the tub 2 and spraying the recirculated fluid into the drum 4. By operating the recirculation pump 20 the liquid is sprayed directly onto the laundry, which for example results in a much more homogeneous wetting of the laundry while rotating the drum 4.
Fresh water is supplied from the home water supply via a valve 24 controlled by control unit 16. A fresh water line 26 connects valve 24 to the inside of the tub 2. As not shown herein, the fresh water line 26 may be connected to a washing detergent unit to provide the washing detergent together with the fresh water into the tub 2. The detergent unit may include one or more fluid or solid detergent compartments, including for example a prewash detergent, a main wash detergent and so on. In an alternate embodiment, the fresh water may directly be supplied into the washing tub 2 bypassing the detergent compartments.
Fig. 2 shows an exemplary method for controlling the wetting program sequence using the program code run on the control unit 16. In step 100 the washing program is started after the user has selected a washing program. Normally there is a plurality of washing programs to be selected by the user depending on the type of fabrics to be washed and the degree of soiling. Then the control unit 16 selects and starts 110 a wetting program sequence which is optimized for standard conditions for the selected washing program. When in step 110 the wetting program sequence is started, the motor is monitored in step 112. Alternatively or in addition to step 112 the weight of the loaded laundry is monitored in step 114.
It is to be noted that for a modification of the wetting program sequence the signals from monitoring the motor 112 or from monitoring the laundry weight 114 are used for further processing and calculating the modification parameters for the wetting program sequence. Both signals maybe used in combination as well. Of course, the dry weight detection step 114 is only performed at the beginning of the wetting program sequence and a modification is then made for the residual process. Or the initial weight value is used as an additional parameter unchanged from the beginning of the wetting program sequence to be combined with the values monitored in step 112. Thus a continuous modification of the wetting program sequence in progress can be done including the initial dry weight.
In step 116 the weight data from step 114 and/or the motor data from step 112 are processed in the control unit 16 and the processing result is used in step 118 to decide whether the wetting program sequence is to be continued with standard wetting program sequence parameters as shown in step 120, or the process has to be continued with modified wetting program sequence parameters such that the program continues with step 130. In step 130 it is decided whether the processing result from step 116 indicates an abnormal or excess state, which may result in a permanent damage of the washing machine or the laundry, and the program proceeds from step 130 to step 300.
In step 300, the abnormal state of the washing machine is indicated to the user by an acoustic and/or visual signal' for example at the panel 18, and the program proceeds to step 302 where the washing program is terminated. When the washing program is terminated a training pump (not shown) drains the washing tub 2, the fresh water valve 24 is closed and no further action is taken.
If in step 130 it is decided that no abnormal or critical state is detected, the program proceeds to step 132 for a parameter processing wherein the type and degree of modification of the wetting programs sequence is calculated in dependency of the motor value monitored in step 112 and/or the dry weight data retrieved in step 114. According to the parameter processing, one or more of the modification steps 134 to 140 are selected which replace the standard wetting program sequence step 120 and are described in more detail below.
In step 122 it is decided whether the wetting program sequence is finished or not. If the wetting program sequence is finished, the program proceeds to step 200 where the next washing program step is started. If in step 122 it is determined that the wetting program sequence is not finished, the program repeats the sequence from steps 112 onward. As mentioned above, step 114 is only used in the starting phase, i.e. the first time passing the flow diagram at this point. By repeating the sequence from step 112 this particular embodiment of the method for wetting laundry results in a repeated adaptation of the modified wetting program sequence, and when it is determined in steps 112, 116 and 118 that the wetting progress results for example in a decreased friction, then the standard wetting program sequence can be resumed in step 120. In this case, the modification takes only place in a limited period during the wetting program sequence as long as the friction value is high.
In an alternate embodiment or as mentioned in connection with the dry weight detection step 114, the modified wetting program sequence can permanently be used until the end of the wetting program sequence.
The modified program steps 134 to 140 result in a modification of the sequence as follows:
In step 134 the drum rotation is immediately stopped while fresh water is supplied into the tub 2 through fresh water line 26. This hold time is continued for a predetermined time (compare Fig. 3b) and after the predetermined hold time or pause the program is continued at step 122.
In step 136 (compare Fig. 3c) the rhythm of drum rotation as compared to the standard wetting program sequence is changed. In this case the rotation duration to the left and right directions are shorter than in the standard rotation cycles while different hold times (times without rotations) between the rotation sequences are used. Additionally or alternatively the rotation speed is modified for the left and/or right rotation as compared to the standard rotation speed.
In step 138 the rotation is immediately stopped and a rotation to the other direction is initiated immediately or after a hold time (see Fig. 3d) as soon as the friction or power consumption of the motor 6 exceeds a threshold value.
In step 140 the wetting of the laundry in the drum is accelerated in that the fresh water is supplied directly onto the laundry using nozzle 23 or by starting the recirculation system and spraying the liquid from the bottom of the tub 2 onto the laundry using nozzle 23. This can be done during a rotation of the drum or a hold period.
Fig. 3a shows the friction F of the drum 4 over time and the rotation speed n of the drum in an arbitrary scale after starting the wetting program sequence. The bold line schematically shows the rotation speed n of the drum 4 with clockwise and counter clockwise rotations. The fine line shows the detected friction F which is for example detected according to Fig. 1 by the power controller 10 which sends the power consumption signal to control unit 16 for processing this signal. From the time of starting the wetting program sequence (t = 0) to time t_E the standard wetting program sequence is executed by control unit 16 according the selected washing program. At time t_E the friction value F exceeds the maximum allowable friction threshold which is indicated in Fig. 3a by the horizontal dotted line. From t_E onward the standard wetting program sequence is stopped and a modified wetting program sequence (Fig. 3b to Fig. 3d) is started.
After a period of modified wetting program sequence the standard wetting program sequence can be resumed as also shown in Fig. 3b to 3d. Resuming may also include a phase shift of the standard wetting program sequence as compared to the sequence from the starting time t = 0 onward.
In Fig. 3b (compare step 134) at time t_E the rotation of the drum is stopped and an additional pause is inserted into the program sequence before the sequence continues with the standard wetting program sequence.
In Fig. 3c (compare step 136) the drum rotation is also stopped and after a pause a reversed rotation with a reduced rotation speed is started. The wetting sequence from time t_E to t_R is a period in which the drum rotation intervals are shorter than in the standard wetting sequence and also the drum rotation speed is reduced. After the time t_R the standard program sequence is resumed.
In Fig. 3d the drum rotation direction is immediately reversed at time t_E and after this rotation inversion the standard wetting program sequence is also resumed.
As mentioned above, the different measures in steps 134 to 140 maybe combined in any possible composition and each measure maybe applied in full or partial degree. For example, the immediate inversion of the rotation direction as shown in Fig. 3d at time t_E may be initiated and a period of alternated rotation duration and rotation speeds as shown in Fig. 3c may follow. Or the immediate inversion of the rotation direction may be accompanied by a water supply directly onto the laundry as described in connection with step 140.

Reference Numerals List

1: washing machine
2: washing tub
4: drum
6: motor
8: belt
10: power controller
12: temperature sensor
14: weight sensor
16: control unit
18: input/monitor panel
20: recirculation pump
22: fluid line
23: nozzle
24: valve
26: fresh water line
100: start washing program
110: start wetting procedure
112: motor monitoring
114: weight detection
116: processing

118: decision on parameter
120: normal wetting procedure
122: control of wetting time
130: decision on abnormal state
132: parameter processing
134: stop drum movement/wetting
136: shorter reversing interval
138: increase wetting speed
140: immediate rotation change
200: next washing program sequence
300: warning
302: termination of washing program

Claims

Method for wetting laundry in a washing machine (1) having a washing drum (4), the method comprising the steps of:
starting (100) a wetting program sequence;

monitoring (112) at least one physical value (F) related to the rotation of the washing drum; and

modifying (132-140) the wetting program sequence in dependency of the at least one monitored physical value (F).
Method for wetting laundry in a washing machine (1) having a washing drum (4), in particular the method according to claim 1, the method comprising the steps of:
detecting (114) or requesting the weight of the laundry loaded in the washing drum (4); and

modifying (132-140) the wetting program sequence in dependency of the laundry weight.
Method according to claim 1 or 2, wherein modifying (132-140) the wetting program sequence comprises modifying at least one drum rotation parameter (n) and/or at least one parameter of the liquid supply to the washing drum (4).
Method according to claim 3, wherein the at least one drum rotation parameter (n) includes at least one of the drum rotation speed, the direction of rotation, the duration and/or start times of rotation intervals and/or stop intervals.
Method according to claim 3 or 4, wherein the at least one liquid supply parameter includes at least one of the liquid flow rate, the liquid total amount, the liquid supply interval, and the liquid supply channel (22, 23).
Method according to any of the previous claims, wherein the physical value (F) related to the drum rotation is the torque for rotating the drum, the rotation speed, and at least one parameter of the motor driving the drum (4).
Method according to claim 6, wherein the motor parameter includes at least one of a motor current, a power consumption, a motor temperature, and a control value for controlling the drum rotation.
Method according to any of the previous claims, wherein the monitoring (114) of at least one physical value (F) and modifying (132-140) the wetting program sequence comprises:
detecting the at least one physical value (F);

processing (132) the at least one detected physical value; and

modifying (140) the wetting program sequence in dependency of the processing result.
Method according claim 8, wherein
the processing (132) comprises comparing the at least one detected physical value (F) with at least one threshold value; and
the wetting program sequence is modified, if the detected physical value (F) exceeds or corresponds to the threshold value.
Method according to any of the previous claims, wherein a signal indicates the user of the washing machine (1) an abnormal state and/or that the washing program is terminated, if the monitored physical value (F) and/or laundry weight exceeds a predefined value for a preset time and/or exceeds a critical value.
Method according to any of the previous claims, wherein the wetting program sequence is modified in dependency of a selected washing program in addition to the at least one monitored physical value (F) and/or the laundry weight.
Washing machine comprising:
a washing drum (4) arranged in a washing tub (2);

a control unit (16) adapted to control a plurality of program sequences;

a detection unit (10, 12) adapted to detect at least one physical value (F) related to the rotation of the washing drum (4) and/or a weight unit (14, 18) adapted to provide weight data of the laundry loaded into the drum (4); and

at least one connection line connecting the detection unit (10, 12) and/or weight unit (14, 18) and the control unit (16), adapted to transmit a physical value signal and/or the weight data to the control unit;
wherein the control unit (16) is adapted to modify a wetting program sequence in dependency of the physical value signal and/or the weight data.
Washing machine according to claim 12, wherein the detection unit (10, 12) comprises a torque meter adapted to detect the torque acting to rotate the drum (4).
Washing machine according to claim 12 or 13, wherein the detection unit (10, 12) comprises a motor detector adapted to detect at least one of the motor current, the motor power consumption, a motor temperature, and a motor control value.
Washing machine according to claim 12, 13 or 14, wherein the detection unit (10, 12) comprises a rotation speed detector adapted to detect the motor and/or drum rotation speed.
Washing machine according to any of claims 12 to 15, wherein the weight unit (14, 18) comprises an input panel (18) arranged to input the laundry weight by the user of the washing machine.
Washing machine according to any of claims 12 or 16, wherein the weight unit (14, 18) comprises a weight sensor (14) adapted to sense the weight of the laundry loaded into the drum (4).