WO2008003577A1

WO2008003577A1 - Method for treating laundry as well as a program-controlled washing machine suitable for this purpose

Info

Publication number: WO2008003577A1
Application number: PCT/EP2007/055963
Authority: WO
Inventors: Thorsten Schiegl; Cornelia Witt
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2006-07-04
Filing date: 2007-06-15
Publication date: 2008-01-10
Also published as: PL2044252T3; EP2044252B1; DE102006030891A1; EP2044252A1

Abstract

A method for treating laundry in a program-controlled washing machine with a sensor (15) for determining the height of a liquid in the liquor container (1), the sensor signal of which is recorded during the method, and a drum (2), characterized in that, in a wetting phase a) while the drum (2) is rotating, water is filled in until a specified threshold value (p1, p2, p3) is reached for the hydrostatic pressure p and until a specified threshold value ((p/t)1, (p/t)2, (p/t)3) is reached for the temporal gradient of the hydrostatic pressure p, and/or b), at a specified time (t1, t2, t3) in the method, the rotation of the drum (2) is stopped and the filling-in of water is ended, and the change in the hydrostatic pressure p because of the water running back is evaluated for determining a loading amount; as well as a washing machine suitable for carrying out the method.

Description

Process for the treatment of laundry as well as suitable program-controlled washing machine

The invention relates to a method for treating laundry in a program-controlled washing machine and to a washing machine which is particularly suitable for carrying out this method. In particular, the invention relates to a method for treating laundry with a wetting phase, in which the addition of water can be controlled by comparing measured values with predetermined threshold values.

When adjusting the amount of water required for washing in program-controlled washing machines especially the wetting phase should be optimized so that each batch of laundry is wetted completely and evenly with a coordinated amount of water in the tub before the actual washing process in the shortest possible time.

DE 10 2004 039 662 A1 describes a program-controlled washing machine with a wetting process, which can be adapted to the amount of laundry in a laundry drum rotatably mounted in a tub about a non-vertical axis by means of a water supply system and a control device, by which the supply of water is temporally controllable in the tub, wherein the wetting process in as many phases (Ph1 to Ph3) is divided, as quantity levels (small, medium, large) are provided for the laundry to be treated.

However, the previously known wetting processes or phases can be further optimized. For example, the known wetting processes still take into account too little different amounts of laundry, so that in the case of very large items of laundry (ie laundry items near the loading limit), no complete wetting takes place. In contrast, the wetting phase for small items of laundry often takes too long, measured by their wetting success. In addition, in the known wetting processes, the uniformity of wetting can be further improved. The object of the invention was therefore to provide a method for treating laundry in a program-controlled washing machine, in which the wetting phase can be controlled so that a laundry item is detected quickly and accurately.

It was also an object to show a suitable washing machine for carrying out this method.

According to the invention, these objects are achieved by a method having the features of claim 1 and by a washing machine having the features of claim 8. Advantageous embodiments of the invention are listed in the subclaims.

The invention thus relates to a method for treating laundry in a program-controlled washing machine with a sensor for determining a level of the liquid in the tub (i.e., the hydrostatic pressure p) whose sensor signal is recorded during the process and a drum, in a wetting phase

a) during the rotation of the drum water is filled until reaching a predetermined threshold for the hydrostatic pressure p and until reaching a predetermined threshold for the temporal gradient (.DELTA.p / .DELTA.t) of the hydrostatic pressure p in the tub, and / or

b) at a predetermined time in the process, the rotation of the drum and the filling of water is stopped and the change of the hydrostatic pressure p is evaluated due to returning water to determine a loading amount.

In method step a), the hydrostatic pressure p measured with the aid of the sensor can be compared with the filled-in amount of water q. The laundry in the drum absorbs water, which therefore does not increase the hydrostatic pressure can contribute. By comparing the measured hydrostatic pressure and the accumulated amount of water - the absolute values p, q and their temporal change (.DELTA.p / .DELTA.t), (.DELTA.q / .DELTA.t) - with corresponding values stored in the program control of a washing machine for the moistening of laundry can be determine the amount of laundry in terms of its quantity, its pumping speed and its degree of moisture penetration (degree of wetting). As a result, the duration of the wetting phase and the amount of water required for wetting can be tailored very precisely to the given amount of laundry.

According to the invention, it is essential in process step a) that water is introduced until a predetermined threshold value pi for the hydrostatic pressure p and a predetermined threshold value (Δp / Δt) i for the temporal gradient of the hydrostatic pressure p is reached. This will generally signal to the program a sufficient wetting of the laundry cost, so that the actual washing can begin.

If, in process step a), the hydrostatic pressure p and / or a predetermined amount for the process step a) has reached a predetermined value, but the gradient (.DELTA.p / .DELTA.t) i not, the filling of water is stopped and it can continue in the Water is introduced into the tub via a pre-set hysteresis, preferably via a small hysteresis. For the purpose of the invention, "hysteresis" is the pressure difference between the pressure at the upper switching point for the water supply and the pressure at the lower switching point for the water supply According to the invention, it is preferable for this pressure difference (hysteresis) to be in the range from 10 to 150 Pa, more preferably from 20 to 100 Pa and most preferably in the range from 30 to 70 Pa.

When using method step b), the predetermined point in time ti is generally based on specific points that are to be classified as critical with regard to the distinctness of the laundry loadings. Such a point in time is reached, for example, when, in a method for treating laundry, the one actually intended for a particular loading stage (amount of laundry) Amount of water qπ _m jt is reached. Accordingly, in embodiments of the invention, provision may be made for method step b) to be carried out at a plurality of points in time (ti, t ₂ , -3, etc.).

The method step b) is based on the fact that with increasing saturation of the laundry with water more relatively free water is present, which can run back relatively quickly due to gravity from the laundry in the tub. Thus, when the drum is at a standstill, by tracking the time change of the hydrostatic pressure p, it is possible to detect the load of laundry and its wetting or to correct an already recognized load. This can be done for example by comparing the present after a certain time hydrostatic pressure p with a predetermined value. The hydrostatic pressure p determined in this way can preferably be used to vary or adapt the further load-dependent parameters of the wetting phase and / or of the further program sequence. If the comparison of the hydrostatic pressure p present in step b) after a certain time with a predetermined value indicates insufficient wetting of the laundry, in particular further predetermined threshold values p ₂ , P3, etc. for the hydrostatic pressure p and further predetermined threshold values (Δp / Δt) ₂ , (Δp / Δt) ₃ , etc. for a process step a) following the process step b) or another time t ₂ , t ₃ , etc. for a next critical point of a next larger loading stage or to be selected.

In the case of carrying out process step b), with the result that the predetermined value for a certain hydrostatic pressure is not reached, it is preferred according to the invention that the drum is rotated for a few seconds to minutes, preferably at a speed, before the re-water inlet from 10 to 50 revolutions per minute. As a result, the freed water is re-entered into the laundry.

In a preferred embodiment of the method according to the invention, only method step a) is carried out. In an alternative embodiment of the method according to the invention, however, only the method step b) is performed.

According to the invention, however, it is preferred if both process steps a) and b) are carried out. In such a case, even in method step a), the amount of water q filled is measured, and step a) ends when, for the treatment of laundry, the quantity qiimit actually provided for a particular loading stage (amount of laundry) is reached. According to the invention, the water retention capacity of the laundry is therefore preferably used in addition to the suction capacity of the laundry for the determination of criteria for controlling the network phase.

In the method according to the invention, the drum is preferably rotated in a certain direction.

If, in the process according to the invention, water has been introduced until the conditions according to the invention according to steps a) and b) are present, it is generally assumed that the laundry to be treated is thoroughly moistened.

If water has been added until the conditions specified for process step a) and / or b) are present, the wetting phase will generally be completed and a washing process started. However, other method steps, for example, a soaking of the laundry for a predetermined period of time without drum movement done, are performed, which then usually followed by a conventional washing process.

In particular, it can be decided according to a further embodiment of the invention on the basis of the size of the optionally determined in the process steps a) and / or b) laundry costs that further special wetting steps or other treatment steps, possibly with reversing drum movement. In this case, if necessary, the water supply can also be interrupted.

In an advantageous embodiment of the invention, the direction of rotation of the laundry drum corresponds to the direction of the effectiveness of a scooping device. Here, the laundry is thoroughly moistened, so that the amount of the accumulated water can be determined more accurately.

For the determination of the filled amount of water q may be a measuring device may be present, for example, a timing device for determining the opening period of a feed valve for the water or a liquid amount measuring device for measuring the amount of liquid filled.

The invention also relates to a washing machine with a program control for controlling the program flow, a rotatably mounted in a tub drum, a drive motor for the drum, a sensor for determining the height of the liquid in the tub and switching means for rotating and stopping the drum the switching means and the sensor can perform the method of the invention.

In particular, the program control comprises storage means in which the threshold value or the threshold values p _x , the threshold value or the threshold values (Δp / Δt) _x for the time gradient of the hydrostatic pressure p and the predetermined amounts of water for the respective loading stages are stored. Particularly advantageously, the values can be stored in tabular form, wherein a threshold value p _x for the hydrostatic pressure p and a threshold value (Δp / Δt) _x for the time gradient of the hydrostatic pressure p are assigned to a given amount of water. Advantageously, these values are sorted in an ascending order relative to values of the given amount of water. Thus, the thresholds during a filling operation with a steadily increasing amount of water can be easily read from the table sequentially. In addition, the Program control via at least one comparison device which a measured hydrostatic pressure p, the temporal change (.DELTA.p / .DELTA.t) and / or a supplied amount of water q with one of the variables associated limits p _x , (.DELTA.p / .DELTA.t) _x and q ι _{imit x} compare can and which can generate a signal when exceeded. With such a signal, the switching means for controlling the wetting phase can be influenced. The index x denotes a particular value from a selection of several possible values.

Furthermore, the washing machine in a preferred embodiment comprises at least one of the above-mentioned measuring devices for determining the amount of water q filled.

The invention is illustrated in more detail below with reference to the figures, in which:

Figure 1: a schematic representation of the relevant parts of the invention for a washing machine, Figure 2 is a schematic diagram of a timing of the

Drum speed n (line 18) and the amount of water q (line

19) of a wetting phase according to the invention comprising a plurality

Process steps a) and b), Figure 3: a schematic representation of temporal courses of the hydrostatic

Pressure p for wetting phases of different amounts of laundry and Figure 4: a schematic representation of a time course of the hydrostatic pressure p (solid line) and its temporal

Change (dashed line) during a process step a).

Figure 1 is a schematic representation of the relevant parts of the invention for a washing machine in which a method according to the invention can be carried out. Other embodiments are conceivable. The washing machine of the embodiment shown in Figure 1 comprises a tub 1, in which a drum 2 rotatably mounted and can be operated by the drive motor 14. According to recent findings for ergonomics in dealing with such Washing machines is the axis of rotation 3 of the drum 2 from the horizontal by a small angle (eg 13 °) directed forwardly upwards so that you have easier access and insight into the interior of the drum 2. By this arrangement, in conjunction with specially shaped Wäschemitnehmern 4 and 5 Schöpfeinrichtungen for the wash liquor 6 on the inner surface of the drum shell also also an intensification of the flow of the laundry 7 with wash liquor and a reduction of the free liquor reached, ie the amount of wash liquor in the tub which can not be absorbed by the saturated laundry (substantially below the lowest point of the drum 2). The invention is not limited to a washing machine with such an inclined drum axis, but can also be used in other washing machines with a rotatable in a tub, in particular about a substantially horizontal axis rotatably arranged drum.

The washing machine also has a liquor inlet system comprising a water connection fitting for the domestic water network 8, an electrically controllable valve 9 and a supply line 10 to the tub 1, which may optionally also be guided via a Waschmitteleinspüleinrichtung ("Einspülschale") 11, from which the feed water In addition, a heating device 13 is located in the tub 1. The valve 9 as well as the heating device 13 can be controlled by a control device ("program control") 12 in accordance with a program flowchart which corresponds to a time program and / or or to the attainment of certain measured values of parameters such as liquor level, liquor temperature, speed of the laundry drum, etc., within the washing machine, in particular to the threshold values predetermined in process steps a) and / or b). 15 means a sensor for the measurement of the hydrostatic pressure p in the tub 1. The hydrostatic pressure p results from the level height H of forming in the tub 1 free fleet. In addition, the washing machine comprises a measuring device 16 for determining the amount of water q filled. You can, for example, as a water meter or as a Be formed flow meter. In the case of a flowmeter, the amount of water q is calculated in conjunction with a detected filling time. It is also conceivable to determine the flow by measuring the time to reach a predetermined level height, which corresponds to a certain fixed amount of water. The signal of the measuring device 16 is supplied to the control device 12.

The invention has numerous advantages. With the method according to the invention, it is possible to estimate the amount of laundry to be treated in a simple and reliable manner in order to adapt the further course of the wetting phase to it. In particular, it is easy to differentiate between different loadings or loading stages.

In one embodiment, as shown in Figure 2, at the beginning of a wetting phase A, the process step a) (phase B) during a continuous rotation of the drum 2 at a speed n1, preferably at a speed of 10 to 50 revolutions per minute, water the tub 1 supplied. The direction of rotation of the drum 2 is in an optimal direction for the scooping device 5 17, whereby the present in the tub water 6 is returned to the drum 2. During the phase B, the detected values for hydrostatic pressure p, their temporal change (Δp / Δt) and the supplied amount of water q are measured and each associated limit values pi, (Δp / Δt) i and q ümit 1, which for one for small load of normal absorbency apply, compared. For such a comparison, the control device 12 comprises a comparator 121 to which the measured values and the limit values are supplied. If one or more limit values are exceeded, the comparator 121 can generate a signal which is used to further control the method and / or the further program sequence.

In an alternative embodiment, the rotation of the drum 2 is reversing. Such a design is used in particular for washing machines that have no scooping device 5. During the filling of the water, the hydrostatic pressure p increases depending on the laundry load 7 and its pumping speed. Depending on the actual laundry load 7, its pumping speed and the geometrical dimensions of the tub 1 and the drum 2, the time change (Δp / Δt) of the hydrostatic pressure p varies. An example is shown in FIG. Only at the time t _(Δp / Δt) 1, both the hydrostatic pressure p exceed the threshold value pi and the time change (Δp / Δt) of the hydrostatic pressure p exceed the threshold value (ApZAt) ₁ . If these two threshold values are reached before the water quantity q π given by 1 for wetting the small loading stage has reached 1, then the process step a) or the phase A is ended, since the achievement of the two threshold values indicates that the laundry charge 7 is sufficiently wetted , A washing phase D can now be connected directly to phase A. Such a process occurs when in fact a small load of laundry 7 has been introduced into the drum 2.

If the laundry load 7 is more absorbent than assumed or if there is a larger laundry load 7, the filled amount of water q previously reaches the limit q ümit 1, which was set for a small loading quantity, ie it is a first critical point for the distinctness, the time ti, reached. Thus, process step b) (phase C) begins. Turning the drum 2 and filling the water are stopped. Now, when the drum 2 is at a standstill, the hydrostatic pressure p or its temporal change (Δp / Δt) is tracked. The comparison of the present after a certain time hydrostatic pressure p with a predetermined value checked on the one hand in the process step a) determined wetting degree of the laundry 7 and on the other hand, a previously determined amount of laundry charge and / or their pumping speed can be determined more accurately. If the comparison reveals that sufficient wetting of the laundry 7 has not yet taken place, the drum 2 is again rotated in order to return the water 6 released to the laundry charge 7. Preferably, the drum 2 is driven with the suitable speed for scooping n1 in continuous rotation in the direction of the arrow 17. After a short period of time, a process step a) (phase B ') is followed again and the wetting phase is prolonged. The extended wetting phases 'denotes or A ". For the phase B' in Figure 2 A are the limits P2 (Ap / At) ₂ and q π _m j _{t 2,} which are valid for a normal for an average load amount absorbency , fixed, ie a second criticality point reached at time t ₂ , is selected The phase B operation described above repeats itself correspondingly in phase B '.

If in the phase B 'of the set for an average wash load limit value q _l i _m i _{t 2,} is reached first or if) (Phase C) determined in a subsequent process step b a larger or more absorbent laundry load than for medium normally absorbent laundry load can, further process steps b) and a), for example, phase B ", in which the limits P ₃ , (.DELTA.p / .DELTA.t) ₃ and predetermined for a given amount of water a limit q ι _imit 3, which is normal for one for a large load Absorbency apply.

In order to avoid an overfilling of water, the measured amount of water is compared with a maximum predetermined amount of water q πmit max, which must not be exceeded during the wetting phase. When the maximum amount of water q πwith max during the wetting phase is reached, the filling of water and the active wetting phase are ended. This is followed by the normal washing phase D. In the washing phase D, as shown in FIG. 2, the drum 2 can be operated at a speed n ₂ suitable for washing, which is higher than the speed ni of the wetting phase. During the washing phase D, further filling of water may be provided via a preset hysteresis.

An example of a time course of the hydrostatic pressure p is shown in FIG. The course corresponds to the courses of the wetting phases A, A 'and A "shown in Fig. 2. Shown in Fig. 3 are respective courses for a small (1 kg), a medium (3 kg) and a large (6 kg) loading stage , With the method according to the invention, the wetting phase can be automatically adapted to the amount of laundry of a laundry item, so that with uniform wetting the laundry is wetted before the actual washing process with the optimum amount of water or alkali.

The inventive method for wetting laundry is equally suitable for wetting of dry laundry at the beginning of a wash cycle as well as for wetting wet laundry at the beginning of a rinse cycle. Deviating limit values or threshold values may be specified for the latter case.

Claims

claims

A method for treating laundry in a program-controlled washing machine with a sensor (15) for determining a level of the liquid in the tub (1), the sensor signal is recorded during the process, and a drum (2), characterized in that a wetting phase

a) during the rotation of the drum (2) water until reaching a predetermined threshold value (pi, P2, P3) for the hydrostatic pressure p and until reaching a predetermined threshold value ((Δp / Δt) i (Δp / Δt) ₂ , (Δp / Δt) ₃ ) is filled for the temporal gradient of the hydrostatic pressure p, and / or

b) at a given time (ti t ₂ , t ₃ ) in the process of turning the drum (2) and the filling of water is stopped and the change of the hydrostatic pressure p is evaluated due to returning water to determine a loading amount.

2. The method according to claim 1, characterized in that method step a) and not method step b) is performed.

3. The method according to claim 1, characterized in that method step b) and not method step a) is performed.

4. The method according to claim 1, characterized in that method step a) and process step b) are performed.

5. The method of claim 1, 3 or 4, characterized in that for the step b) the time (ti t ₂ , t ₃ ) is reached when the filled water predetermined for a given loading level amount (q ι _imi t , q Nmit2, q Mwith 3).

6. The method of claim 1, 3 or 4, characterized in that the drum (2) is rotated in front of a renewed water inlet for a few seconds or minutes at a speed of 10 to 50 revolutions per minute.

7. The method according to any one of claims 2 to 6, characterized in that the method step a) and / or the method step b) are repeated.

8. Washing machine with a program control (12) for controlling the program sequence, a in a tub (1) rotatably mounted drum (2), a drive motor (14) for the drum, a sensor (15) for determining the height (H) of in the tub (1) located liquid (6) and switching means (9, 12, 14) for rotating and stopping the drum (2), characterized in that the switching means (9, 12, 14) and the sensor (15) a method can carry out according to one of claims 1 to 6.