DE102006060256A1 - Method for controlling a washing machine - Google Patents

Abstract

A washing machine (11) is designed by means of a special controller (26) and a conductivity sensor (24) in the tub (17) to detect a water level (25) or to detect whether a certain water level (25) exceeded or fallen below becomes. For example, the controller (26) may control operation of the pump (20), as well as the addition of fresh water to remove too much foam in the tub (17) or in the drum (13). It can also stop the drum (13) to drain off disturbing foam.

Description

The The invention relates to a method for controlling the operation of a Washing machine, being in a tub of the washing machine Conductance sensor is arranged.

It is for example for controlling the operation of a washing machine from the DE 10 2005 007 935 A1 or the EP 633 342 A1 known to provide a conductivity sensor inside, for example, in the lower region of the tub. The measured values of the conductivity sensor are recorded and evaluated by a controller of the washing machine. However, the possibilities described therein of further processing or utilizing these measured values are limited.

Task and solution

Of the Invention is based on the object, an aforementioned method to create with the functionality of a washing process or operating method a washing machine or the evaluation of an aforementioned Leitwertsensors improved can be.

Is solved this object by a method having the features of the claim 1, claim 3, claim 5, claim 6, claim 9 or claim 12. Advantageous and preferred embodiments The invention is the subject of the further claims and will become hereafter explained in more detail. It is above all also possible several of the aspects of the invention combine. The wording of the claims is expressed by express Reference made to the content of the description.

at a first fundamental Embodiment of the invention is provided that by the conductivity sensor the water level is recorded and, if the water level drops lower is stopped as the arrangement of the conductivity sensor, emptying the tub is, in particular a pumping with a pump. To this One way is to drain the pump when completely depleted tub be prevented, which on the one hand avoids unnecessary energy consumption and on the other hand, especially in those phases in which the drum not spinning, unpleasant audible Sounds avoids.

In front all if for emptying the tub an aforementioned pump is provided, it is advantageous when switching off the pump after the fall of the water level below the conductivity sensor only with some Seconds delay takes place. Such a delay In particular, it can be adjusted to ensure that the water level is at normal pumping power even further below the conductivity sensor is lowered, however, an idling of the pump or a suction of air at the pump is avoided. This will ensure that an operation of the pump close to an optimal area to be considered takes place, ie emptying the tub or lowering the water level until just above the pump. However, this does not necessarily have to be the case The pump can also be switched off when the water level is below it located. It is important that it can be determined where the Water level relative to the pump is possibly too noisy avoid.

According to one further basic Embodiment of the invention, the conductivity sensor is designed to to recognize when washing, whether it is surrounded by foam. Especially this can not only be detected by the conductivity sensor itself, but also in cooperation with the control of the washing machine or a controller for the conductivity sensor. As a countermeasure Fresh water is added to reduce or eliminate the foam. So the foam or the liquor are at least diluted and Foam as possible away. A detection of foam on the conductivity sensor is so within the scope of the invention with good security possible. Especially with capacitive Conductance sensors have measured values for this foam state on Conductance sensor between those for air and such in case that the conductivity sensor is surrounded by water.

Here is it still possible, as a countermeasure Add as much or as long as fresh water to foam, until too while the washing process or during turning the drum of the conductivity sensor predominantly or, especially advantageous, always surrounded by water. So can the negative effects to avoid too much foam during washing.

According to a further basic embodiment of the invention, the surface tension of liquor in the drum or in the liquor can be detected by the conductivity sensor by detecting the ion concentration in the liquor. Based on this, it can be determined whether a certain surface tension has been exceeded and rinsing of the laundry can be ended. It can in fact be detected in this way, so to speak, whether the detergent has already been rinsed sufficiently from the laundry. For example, depending on the detected ion concentration, the length and / or the number of rinses can be adjusted. In particular, this is done until the ion concentration or the surface tension has exceeded a certain predetermined value and there with the laundry as sufficiently rinsed applies.

According to one further basic Embodiment of the invention, it is possible during the spinning process, especially with constantly running pump, the spin speed only to increase so long until the conductance sensor essentially without interruptions or even constantly surrounded by water. This means that with slow spin speeds is started, because then still very wet laundry sufficient water from the Laundry is thrown out, so that the water level exceeds the conductivity sensor. As a rule, the pump capacity is limited or the pump always running at maximum power, It does not make much sense to do the laundry even faster to hurl and throw out even more water, though this then by the pump not timely or fast enough transported away can be. Furthermore, then the laundry in the drum again and again be twisted through the water in the bottom of the tub and wet again, what should be avoided.

Advantageous is it additional possible, to increase the spin speed only when the conductivity sensor after a longer one Time, especially after a few minutes, during which he is constantly or quite predominantly was surrounded by water, then no longer or mostly no longer of water is surrounded. This means that then keep the pump with the coming out of the wash water can or can remove it and thus be flung again stronger or faster can. The spin speed can then be particularly slow increased so long until the conductivity sensor is again mostly or always water is surrounded. This can be repeated several times or the spin speed can be increased more and more. By this slow Increasing the spin speed unnecessarily early or fast spin the drum with the associated energy consumption and bearing wear avoided.

It can be advantageously provided via the conductivity sensor or its measured values to control the operation of the pump. It is possible, for example, at Reaching a maximum spin speed then turn off the pump if the conductivity sensor is no longer or predominantly out of water is surrounded. Advantageously, it will be switched on again only then, if the conductivity sensor is always or predominantly surrounded by water. So it is possible that the pump does not run constantly at maximum spin speed. The The above-described emptying of the pump with suction of air is indeed in terms of noise nuisance during the Skidding, especially at high speeds, not critical, because it is much quieter than the skidding. However, it can be an unnecessary energy consumption and wear on the pump can be reduced.

Especially advantageous it is possible that between a state change at the conductivity sensor, ie between the state of the predominantly of Surrounded by water and the condition of the predominantly exposed conductivity sensor, and turning the pump on or off for a period of time Seconds is waited, as already described above has been. This time span can be, for example, in the range between 5 and 30 seconds, in particular between 10 and 20 seconds. As already described above, this short time span is also here provided that further pumped out water while the pump continues until shortly before the pump runs dry. With the pump stopped and rising water is waited until the water level over the Conductance sensor has risen, but not yet reached the wash again Has. This is how the switching frequency becomes reduced at the pump.

According to one further basic Embodiment of the invention, as stated above, on Conductance sensor can be determined whether it is from water, foam or air is surrounded. Thus, in a spin operation, a speed of the Drum can be reduced if foam is detected on the conductivity sensor becomes. Reducing the speed of the drum is a countermeasure to Reduction of foaming, since the foam then less or not further pitched by the passing through him drum becomes. For example, reducing the speed may be up to 10% 30%. In particular, the speed can be slow or in stages be lowered until the conductivity sensor is no longer surrounded by foam is. It may be even possible that the drum is completely stopped if the conductivity sensor always is still surrounded by foam. It is particularly advantageous, after Stopping the drum to wait a few minutes, for example until to five Minutes. If the conductivity sensor is still surrounded by foam then or he recognizes foam, so can as a further countermeasure fresh water let in to flush away the foam. After admitting the Fresh water with a certain amount or for a certain time checked again, whether the conductivity sensor is surrounded by foam. Is that the case, Fresh water can be added again until the foam is removed is. As another test measure can the pump will be started. Running they namely empty, which for example by measuring the power consumption of the Pump can be easily detected, and this takes a few seconds to a few minutes, that is indeed foam is still present at the conductivity sensor.

According to one yet another fundamental Embodiment of the invention, it is possible in a method for the operation of an aforementioned conductivity sensor or during the measurement the conductivity in the tub or in the fleet a washing or rinsing process, in particular also a spin process, interrupting briefly to carry out the Conductance measurement. In particular, in the event of an interruption or for the Conductivity measurement the drum stopped until it stops and then the conductivity measurement is carried out with the drum stationary. Thereby it is avoided that the fleet pitched by the drum movement in the tub or struck until foaming becomes. Furthermore, then the water in the tub can calm down, which also provides a better and safer evaluation of the conductivity sensor allows.

Farther is it possible within the scope of the invention that one of normally two mandatory safety circuits for the Heating is not required, there with the conductivity sensor in the context of the above-described water level measurement It can be determined whether the heater is in the water. This allows a simpler structure of a washing machine.

These and other features go out the claims also from the description and the drawings, wherein the individual features each for alone or in the form of subcombinations an embodiment of the Invention and other fields be realized and advantageous also for protectable versions can represent for the protection is claimed here. The subdivision of the application into individual Sections and intermediate headings restrict the not in its generality among these statements.

Brief description of the drawings

embodiments The invention are shown schematically in the drawings and will be closer in the following explained. Hereby show:

1 a schematic interior view of a washing machine according to the invention and

2 to 4 various diagrams to illustrate the relationships between surfactant concentration, surface tension and conductance.

Detailed description the embodiments

In 1 a washing machine according to an embodiment of the invention is shown with a drum 13 in which is laundry 14 located. The drum is driven 13 through the engine 15 with a belt drive. A tub 17 is below the drum 13 provided or surrounds it and has an outflow 18 on. This drain 18 leads to a pump 20 which water from the tub 17 via a drain hose 21 from the washing machine 11 promoted. In the tub 17 a heater protrudes 23 to warm up water or liquor in it. Not shown in 1 a feed for fresh water as well as for the detergent added water. However, this, as well as the washing machine described up to this point, may be designed as in the prior art.

A conductivity sensor 24 protrudes into the tub 17 , In the illustrated embodiment, near the heater 23 as for example from the DE 10 2005 007 935 is known. The conductivity sensor 24 defines a dashed level, so to speak 25 which marks the height to which he can recognize water or foam. This will be discussed in more detail below. Furthermore, the conductivity sensor 24 with a controller 26 connected, which also with the pump 20 and / or the heating 23 may be connected, in particular for their control or for the evaluation of the operating state. Likewise, the engine can 15 with the controller 26 be connected, both driven by this and in addition or alternatively to detect its operating condition as described above.

As described above, the conductance sensor 24 For example, determine if water or foam is above or below the level 25 or whether he himself is immersed in water. This may be decisive, in particular, for the pumping operation described above. In this context, it should also be noted that the conductivity sensor 24 with the level 25 a whole piece below the lowest point of the drum 13 sitting. Thus, a water level can be the conductivity sensor 24 or the level 25 a good deal, without losing the drum 13 as well as the laundry contained therein 14 to get to them and make them wet again. This height difference is to be considered in the previously described, a hysteresis curve similar possibility, when the water over the level 25 the pump 20 only after a certain time to turn on, in any case, but in time, before the water to the drum 13 arrives. The same applies to the drop in water below the level 25 before the pump 20 Dry when pumping.

Since the various possible methods have already been described at the outset, there is no need to go back even further here to discuss them in connection with the 1 but even clearer.

In 2 is shown how to increase the surface tension of the liquor, in which the contents of the drum 13 especially the laundry 14 , based on the surfactant concentration, can measure. Namely, there is a fixed relationship between these, from the particular control 26 can draw the above conclusions.

Similarly, the conductance and the surfactant concentration are related to each other as shown in FIG 3 is shown.

Finally, you can also according 4 the conductance in relation to the surface tension in the liquor in the drum 13 or in the tub 17 put. Then one obtains for different surfactants and different Tensidkonzentrationsbereiche each nearly linear relationships, namely the in 4 ranges shown 1 to 4. Is now the range of surfactant concentration known, for. B. a very high surfactant concentration during the washing process, it can be concluded from the conductivity of the liquor based on the conductance on the surfactant concentration. Is the surfactant concentration rather low, for example when rinsing laundry 14 in the drum 13 , the conductance can also be determined from the fixed context. Because the controller 26 advantageous the entire control for the washing machine 11 she knows the program flow and, of course, knows whether a washing process or a rinsing process is currently taking place. The exact nature of the particular surfactant present need not necessarily be known since, starting from a starting value for any desired surfactant, the change in concentration can be recognized. This is sufficient for the aforementioned optimization of the washing and rinsing operations. In particular, different courses can be used accordingly 4 in the controller 26 be stored and used for detection.

Claims (12)

Method for controlling the operation of a washing machine ( 11 ), wherein in a lower region of the tub ( 17 ) a conductivity sensor ( 24 ) and measured values of the conductivity sensor ( 24 ) and sent to a controller ( 26 ) of the washing machine ( 11 ), characterized in that it is detected when the water level has dropped lower than the arrangement ( 25 ) of the conductivity sensor ( 24 ) and then emptying the tub ( 17 ) is stopped. A method according to claim 1, characterized in that for emptying the tub ( 17 ) a pump ( 20 ) is provided and switching off the pump ( 20 ) takes place with a delay of a few seconds, wherein preferably the delay is coordinated with the water level even further below the conductivity sensor ( 17 ) without lowering the pump ( 20 ) or to cause an intake of air. Method according to the preamble of claim 1, characterized in that the conductivity sensor ( 24 ) when washing detects whether it is surrounded by foam, and fresh water is added as a countermeasure to the foam or the liquor in the washing machine ( 11 ) to dilute. A method according to claim 3, characterized in that as much fresh water is added until even during the washing process or during rotation of the drum ( 13 ) the conductivity sensor ( 24 ) is predominantly or preferably always surrounded by water. Method according to the preamble of claim 1, characterized in that the conductivity sensor ( 24 ) the surface tension of water or alkali in the drum ( 13 ) or detected in the liquor on detection of the ion concentration in the liquor, wherein it is determined on the basis of whether a certain surface tension is exceeded to complete the rinsing of the laundry ( 14 ), wherein depending on the ion concentration, the length and / or the number of rinses are adjusted. Method according to the preamble of claim 1, characterized in that during the spinning process, in particular when the pump is always running ( 20 ), the spin speed is only increased until the conductivity sensor ( 24 ) is constantly surrounded by water. A method according to claim 6, characterized in that the spin speed is increased only when, after a longer time, in particular a few minutes, during which the conductivity sensor ( 24 ) was surrounded by water, the conductivity sensor ( 24 ) is then no longer surrounded by water, wherein preferably the spin speed is increased slowly until the conductivity sensor ( 24 ) is again predominantly or always surrounded by water. Method according to claim 6 or 7, characterized in that via the conductivity sensor ( 24 ) or whose measured values the pump operation is controlled, wherein preferably when a maximum spin speed is reached, the pump ( 20 ) is switched off when the conductivity sensor ( 24 ) is not surrounded by water and is only switched on again when the conductivity sensor ( 24 ) is surrounded by water, wherein preferably between a state change at the conductivity sensor ( 24 ) and switching on / off the pump ( 20 ) a time span of a few seconds, in particular 5 to 20 seconds. Method according to the preamble of claim 1, characterized in that via the conductivity sensor ( 24 ), it is determined whether it is surrounded by water, foam or air, wherein in particular during the spinning process on detection of foam, a rotational speed of the drum ( 13 ) is reduced as a countermeasure or to reduce foaming. Method according to claim 9, characterized in that by the conductance sensor ( 24 ) it can be recognized whether the foam has already been adequately reduced or whether it has passed the conductivity sensor ( 24 ) no longer surrounds and, if this is not already the case, the drum ( 13 ) is stopped altogether. A method according to claim 9 or 10, characterized in that in the event that even after stopping the drum ( 13 ) still foam from the conductivity sensor ( 24 ) is recognized, especially after waiting a certain time of a few minutes, fresh water is introduced to wash away the foam. Method according to the preamble of claim 1, characterized in that a washing or rinsing process is briefly interrupted for carrying out the conductance measurement, wherein in particular for interrupting the drum ( 13 ) is stopped and then with the drum stopped ( 13 ) Conductance measurement is performed.