EP2579760B1 - Method for controlling a dosing appliance for a flowable detergent or washing agent - Google Patents

Description

The invention relates to a method for controlling a metering device of a self-sufficient metering system for flowable detergents or cleaners, preferably for use in a dishwasher with the features of the preamble of claim 1. The invention is also a metering device, with which this method can be performed.

One of the major goals of the machine cleanser manufacturers is to improve the cleaning performance of these agents, with a recent focus on cleaning performance in low temperature or reduced water consumption cleaning cycles. For this purpose, the cleaning agents were preferably added to new ingredients, for example, more effective surfactants, polymers, enzymes or bleach. However, since new ingredients are available only to a limited extent and the amount of ingredients used for each cleaning cycle can not be increased to any extent for ecological and economic reasons, this approach has natural limits.

In this context, in particular, devices for the multiple dosing of detergents and cleaners have recently come into the field of vision of the product developers. In these devices, it is possible to distinguish between dosing chambers integrated in the dishwasher or textile washing machine on the one hand and independent devices which are independent of the dishwasher or textile washing machine on the other hand. By means of these devices, which contain a multiple of the amount of detergent necessary for carrying out a cleaning process, detergent or detergent portions are dosed into the interior of the cleaning machine in an automatic or semi-automatic manner in the course of several successive cleaning processes. For the consumer eliminates the need for manual dosing with each cleaning or washing cycle.

The starting point for the teaching of the present invention is a metering system according to the WO 2010/006761 A2 ,

The following statements relate primarily to the example of a dishwasher, because the method according to the invention and the metering device according to the invention can also be used particularly expediently in a dishwashing machine. However, the statements are generally to be understood that they also apply to other devices in which pose similar problems, especially textile washing machines, which is also working with multiple rinses within a cleaning cycle.

In the known method, from which the invention proceeds ( WO 2010/006761 A2 ), the dosing unit of the dosing system initially has a sensor which is intended and suitable for detecting the water temperature in the dishwasher.

The control of the process of the process is largely on the determined water temperature. Thus, in particular the beginning of the rinse cycle of the dishwasher is detected by the fact that there is a higher water temperature than the normal cleaning rinse or intermediate rinse.

In addition to a temperature sensor, the metering device of the known metering system has a sensor for detecting the conductivity, which is open to the environment of the metering device, in other words, is accessible to the water that is in the dishwasher. In the known dosing device, the conductivity sensor at the bottom of the dosing device on two open towards the environment contacts, which are preferably designed as protruding down from the ground contact pins. One contact is connected as an anode contact, the other contact is connected as a cathode contact with respect to the energy source. These contacts may each be covered with an electrically conductive silicone to less easily corrode. The spacing of the contacts is typically between 2 and 25 mm.

By means of the control unit, the track resistance of the route between the two contacts can be determined, which can be converted into the conductivity of the medium wetting the contacts, in particular the cleaning liquid in the dishwasher. If there is no liquid bridge between the contacts, the conductivity is very low, it is close to zero. If there is water in the dishwasher, that is, if a rinse is taking place, the conductivity sensor which is open to the surroundings in the dishwasher is subjected to cleaning liquid, a liquid bridge is created between the contacts, and the conductivity has become significantly higher. In the above-described prior art, it is only determined by means of the control unit with the aid of the conductivity sensor whether water is present in the dishwasher or whether it is dry. The actual control of the dosing over the course of rinses - cleaning rinse, intermediate rinse, rinse - away, however, takes place by the control unit based on the measurement signals of the temperature sensor.

The teaching is now based on the problem of making the control of the dosing more practical and sensitive.

The aforementioned problem is solved in a method having the features of the preamble of claim 1 by the features of the characterizing part of claim 1.

The essential idea of the method according to the invention is not to control the course of the process via the rinses of the cleaning cycle, cleaning rinse, intermediate rinse or intermediate rinses, rinse cycle, or at least not only by means of the temperature sensor, but also or primarily the conductivity sensor and its conductivity measurements consulted.

It should be repeated again that the representation of the invention takes place here with reference to the preferred example of a dishwasher. However, the application to other facilities with similar issues, in particular a textile washing machine, is expressly implied.

The teaching of the invention is based on the fundamental knowledge that the electrical conductivity in the cleaning liquid depends on the concentration of the electrolyte in the cleaning liquid. As the electrolyte concentration increases, the conductivity increases. The electrolyte concentration increases when detergent is added to the water and / or when the dirt slowly dissolves in the cleaning liquid. The conductivity reaches its maximum during the Reinigungsspülganges as soon as the detergent is completely dosed into it and dissolved and also the entire dirt has detached and passed into the cleaning liquid.

In the course of the further rinsing process, the conductivity changes only slightly by increasing or decreasing the temperature of the cleaning liquid or by dilution processes, for example, when fresh water is added.

Only when at least a partial change of water, the conductivity changes significantly. This situation is exploited according to the invention in order to control the course of the process. A significant change in conductivity usually means a change from one rinse to the next rinse. In particular, this initially applies to the transition from the first, the Reinigungsspülgang, in the second, the intermediate rinse cycle.

Thus, according to the invention, the course of the conductivity over time during the course of the rinse cycles is determined by the control unit with the aid of the conductivity sensor. In addition, the gradient of the course of the conductivity measured values is evaluated. A change from rinse cycle to rinse cycle is only detected if not only the maximum conductivity value determined in the first rinse cycle is exceeded, but only if, in addition, the conductivity drops at a certain minimum speed, ie a certain gradient.

The second criterion provides a high certainty that the change in conductivity actually takes place due to a complete water change and not only due to the addition of smaller amounts of fresh water.

With the method according to the invention, the control of the self-sufficient dosing system is independent of which temperature boundary conditions exist during the course of the dishwashing program. This takes into account the fact that modern dishwashing products manage with lower temperatures than formerly usual. The temperature curves over a dishwashing cycle are therefore no longer always to the extent clearly attributable to the different types of rinses. The same applies to modern detergents, rinse aids and fabric softeners for textile washing machines.

Of particular importance is the doctrine of the invention as to where in the rinse cycle no renewed heating of the cleaning liquid. Particularly affected are those dishwashers in which no more heat energy has to be supplied for the drying following the rinse cycle. There, the dehumidification is usually done rather by adsorption or absorption. The hitherto typical high temperature in the rinse cycle can not be detected here, the temperature sensor is not helpful in this respect.

For particular, the determination of the rinse cycle apply the other versions of the dependent claims, the claims 2 to 6 in particular.

Further preferred embodiments and further developments of the method according to the invention are then the subject matter of claims 7 and 8. According to claim 9, the inventive method is executed with the program control of a program-controlled electronic control unit or causes the corresponding method steps.

In a dosing device according to the invention, the control unit is thus programmed in such a way that, during operation in a dishwasher, it is capable of exerting the previously explained method steps.

Fig. 1

in schematischer Ansicht ein Großgerät, hier dargestellt als Geschirrspülmaschine, mit einem in einer Schublade angeordneten erfindungsgemäßen Dosiersystem,

Fig. 2

das Dosiersystem aus Fig.1 einmal mit vom Dosiergerät gelöster Kartusche, zum anderen mit am Dosiergerät angekoppelter Kartusche,

Fig. 3

ein konkretes Ausführungsbeispiel eines erfindungsgemäßen Dosiersystems mit vom Dosiergerät noch gelöster Kartusche,

Fig. 4

ein Ablaufdiagramm eines Geschirrspülzyklus bezogen auf den Verlauf der Leitfähigkeits-Messwerte in der Reinigungsflüssigkeit.

In the following, the invention will now be explained in more detail with reference to a drawing illustrating only preferred embodiments. In the drawing shows

Fig. 1

a schematic view of a large appliance, shown here as a dishwasher, with a arranged in a drawer according to the invention dosing,

Fig. 2

the dosing system off Fig.1 once with the cartridge dissolved by the dosing device, on the other hand with the dosing device coupled to the cartridge,

Fig. 3

A concrete embodiment of a metering system according to the invention with the dispenser still dissolved cartridge,

Fig. 4

a flowchart of a dishwashing cycle based on the course of the conductivity measurements in the cleaning liquid.

Fig. 1 shows first a large household appliance, here in the form of a dishwasher 1 with an interior, which is accessible in this illustration because of the folded down to the outside front door 2. In the interior there is a drawer 3, shown as a dish rack, in which a metering system 4 is according to the invention. It can be seen that the metering system 4 can in principle be positioned anywhere within the drawer 3 of the dishwasher 1. It is advantageous to have a similar to a plate shaped metering system 4, so that it can be set in a corresponding plate receptacle of the drawer 3.

In Fig. 1 is indicated on the front door 2 of the dishwasher 1, a metering chamber into which a detergent tablet or the like. can be entered. But is that the case? Dosing system 4 according to the invention inside the dishwasher 1, a use of the metering chamber is not required, since the delivery of the detergent or cleaning agent is realized in the interior of the dishwasher by the metering 4.

The basic principle of the dosing system 4 can be found in Fig. 2 ,

The dosing system 4 shown there shows below a dosing device 5 with a housing 6. In Fig. 2 is indicated by dashed lines in the housing 6 to the right an energy source 7, typically a battery or a rechargeable battery, and left next to an electronic control unit 8, typically equipped with a microprocessor or a microcontroller and other conventional components of such a control unit. At the front of the housing 6 are indicated display and / or controls 9, which indicate the operating state of the dosing device 5 and / or can act on this.

At the top of the housing 6 of the dosing device 5 you can see a, designed here as a peripheral edge connecting portion 10 for releasably coupling a cartridge 11 shown above the dosing device 5. This cartridge 11 is thus shown here solved by the dosing device 5. The cartridge 11 has at least one cartridge chamber 12. In the illustrated and preferred embodiment, the cartridge 11 has two cartridge chambers 12, so that two different flowable detergents or cleaning agents can be stored.

The WO 2010/006761 A2 explains very extensively what these laundry detergents or cleaners typically are and what the compositions are. Also in this respect may be made to the state of the art.

On the underside of the cartridge 11 can be found at the two cartridge chambers 12 each outlet 13 of the cartridge chambers 12th

To the outlet openings 13 of the cartridge chambers 12 of the cartridge 11 Dosierkammereinlässe 14 correspond to the top of the housing 6 of the dosing device 5. The Dosierkammereinlässe 14 further comprise means for the attachment / coupling of the cartridge 11 to the housing 6 of the dosing device 5, an opening of the outlet openings 13 effect, so that in the coupled state of the cartridge 11 and dosing device 5, the interior of the cartridge chambers 12 communicating with the Dosierkammereinlässen 14 is connected.

Fig. 2 shows on the right the situation that exists when the cartridge 11 is coupled to the dosing device 5. Here the dosing system 4 is complete and ready for use.

One of the practice closer execution of a dosing system 4 shows Fig. 3 , There you can also see more detailed details of the various cartridge chambers 12 of the cartridge 11, the outlet openings 13 and the Dosierkammereinlässe 14. In particular, one recognizes in Fig. 3 in the dosing device 5 below the Dosierkammereinlässe 14, the metering chambers 15 with associated actuators 16 and closure elements 17. All this is in detail in the WO 2010/006761 A2 described and requires in this respect no further detailed explanation.

In Fig. 3 can be seen in the left half of the housing 6 of the dosing device 5, the control unit 8 with the power source 7, all shown schematically.

In Fig. 3 can be seen at the bottom of the housing 6 of the dosing device 5 indicated a conductivity sensor 18. In this conductivity sensor 18 are outwardly guided contacts, which are wrapped according to preferred teaching of the invention with an electrically conductive silicone to be protected against corrosion. Towards the inside, these contacts are connected in terms of circuitry to the energy source 7 and the control unit 8, so that the corresponding conductivity measurement can be carried out via the contacts of the conductivity sensor 18 in the cleaning liquid in the dishwasher.

The basic construction of the conductivity measurement in the metering device 5 according to the invention is known from the prior art described above and requires no further explanation here. Rather, so far on the WO 2010/006761 A2 to get expelled.

This is about the process by which the dosing device of the dosing system 4 is controlled during use in a dishwasher during a rinsing cycle. This control is performed by the control unit 8.

In accordance with the method according to the invention, it is provided that, during the course of a cleaning cycle, in this case a dishwashing cycle, the conductivity measuring value L currently being ascertained by the conductivity sensor 18 is determined continuously or discontinuously by the control unit 8 with at least two different rinse cycles S ₁ , S ₂ . in that the control unit 8 determines the sequence of determined conductivity readings L with regard to the course of the absolute value of the conductivity and with respect to the gradient of the gradient dL / dt of the conductivity is evaluated and that when the currently measured conductivity measured value L _falls below a determined in the first rinse S ₁ maximum conductivity value L _max and the gradient of the curve dL / dt the Leitfähigskeits- measured values exceeds certain limit value D, this is evaluated by the control unit 8 as a water change and the beginning of the next wash cycle S ₂ .

The typical course of the conductivity L in the cleaning liquid in a dishwasher during a dishwashing cycle shows Fig. 4 ,

At the beginning, no water has yet flowed into the interior of the dishwasher 1, the conductivity sensor 18 is dry, and the conductivity reading is as good as zero. This is because the track resistance between the contacts of the conductivity sensor 18 is extremely high, it is practically only an air gap.

Now fresh water flows into the interior of the dishwasher 1. The dishwashing arms of the dishwasher begin to rotate, and the conductivity sensor 18 is supplied with cleaning liquid, which is still substantially clean water. The conductivity increases abruptly to the typical conductivity for fresh water.

The control unit 8 has therefore first determined by means of the conductivity sensor that the dishwasher is now in operation. Therefore, a timer function of the control unit 8 can be executed, so that the timing at which the first detergent must be dosed into the cleaning liquid can be adjusted. In parallel, it is determined by the temperature sensor, not mentioned here, whether the cleaning liquid in the dishwasher 1 has already reached the correct temperature for optimum cleaning by means of the first cleaning agent.

If the first cleaning agent is metered into the cleaning liquid - point R -, this leads to an abruptly increasing electrolyte concentration. The conductivity, which is measured via the conductivity sensor 18, increases abruptly. You can see that in Fig. 4 very good at this point.

During the further cleaning cycle, dirt dissolves, the temperature conditions change a little and the conductivity readings (L) change slightly. This can be seen by the relatively even, flat course of the curve of the conductivity measurements (L) in Fig. 4 ,

At the end of the cleaning cycle, the dirty cleaning liquid is pumped out. The conductivity measurement value L determined via the conductivity sensor crashes, decreases with a gradient dL / dt which is considerably greater than a previously defined limit value D. This is evaluated by the control unit 8 as the end of the cleaning wash cycle. The dosing device 5 "knows" now that it enters the next rinse S ₂ , the intermediate rinse cycle.

In Fig. 4 can be seen right at the end of the last rinse S ₃ , the rinse cycle that now the rinse aid mixed with rinse aid has been finally pumped out of the dishwasher 1. The conductivity sensor 18 is dry again, the conductivity reading L has dropped to virtually zero. The metering device 5 recognizes after a certain time, which is to be defined over a predetermined time window, that the entire dishwashing cycle has now been completed.

According to the invention, it is further provided in accordance with a preferred teaching that when the second control unit 8 starts the second wash cycle S ₂ again determines that the gradient of the curve dL / dt of the conductivity (L) the limit value D or another, for the second Rinse S ₂ stored limit value D ', this is evaluated by the control unit 8 as a water change and the beginning of the next rinse cycle S ₃ . Since in the intermediate rinse cycle, even if one should again add a cleaning agent, in all likelihood will not set conductivity readings L which is as high as in the cleaning rinse cycle, one will possibly also work with a different limit value D 'for the gradient, to determine the next change to the third rinse.

In some cleaning cycles, there is not only an intermediate rinse, but several intermediate rinses. In order to distinguish a further intermediate rinse from the last rinse, the rinse cycle, can be considered in the context of the method according to the invention further criteria.

In the rinse cycle, it is necessary to trigger the dosage of a further cleaning agent, in this case the drying and rinse aid. According to a further preferred teaching, for this particular situation, a minimum conductivity measured value L _{min is} predetermined in the control unit 8 or determined and stored by the control unit 8 and that it is evaluated by the control unit 8 as the beginning of the last wash cycle S ₃ , the rinse cycle, only if in addition also the minimum conductivity measured value L _{min is} undershot. A first possibility for determining a suitable minimum conductivity measured value L _min is to determine and store it at the beginning of the cleaning cycle, ie with clear fresh water in the dishwasher. Another possibility is to determine and store the minimum conductivity measured value L _min when changing from the first rinse cycle S ₁ to the second rinse cycle S ₂ . The latter has the advantage of usually even lower error rate of the control process.

Thus, if the control unit 8 of the dosing device 5 has determined that there was a cleaning rinse and now also the intermediate rinse has been completed, the dosing device 5 can now dose the rinse aid and / or inside the dishwasher 1 independently of the temperature. or desiccant. In this case, the minimum conductivity measured value L _min in the control unit 8 can be predefined from the outset or can result from the minimum conductivity measured value determined during the transition from the cleaning rinse cycle to the intermediate rinse cycle and stored by the control unit 8. Which of the variants one chooses will depend on the practical test.

To be sure that now really the last, the rinse cycle has begun, it may be advisable to introduce yet another criterion, namely to provide that it is evaluated by the control unit 8 as the beginning of the last wash cycle S ₃ , the rinse cycle, only then If the minimum conductivity measured value L _{min is} undershot and is exceeded again within a predetermined time window after _falling below the minimum conductivity measured value L _min from the current conductivity measured value (L). This prevents accidental metering of the rinse aid and / or desiccant from the dosing device 5 if the dishwashing cycle is prematurely or intentionally terminated.

In principle, it is possible to determine the conductivity measured values L in different ways with the conductivity sensor 18. The conductivity measured values L are preferably determined by a discrete, discontinuous measurement at the conductivity sensor 18 by the control unit 8. Experience has shown that it is expedient if at least 100, preferably at least 200, conductivity measurements or resistance measurements per second by the control unit 8 are made by means of the conductivity sensor 18.

In order to avoid polarization effects, it is further recommended that, after each conductivity measurement or any particular number of conductivity measurements on the conductivity sensor 18, a polarity reversal takes place.

The above explanations have already made it clear that one has to assume in the first place of a program-controlled electronic control unit 8, which corresponds to today's state of modern development and will regularly include a microprocessor or microcontroller. Of course, the control unit 8 also has corresponding other modules, in particular electronic data storage.

According to the invention, it is therefore recommended that it is a program-controlled electronic control unit 8 and that the method steps are executed or initiated by the program of the control unit 8.

As has already been stated above, the subject of the invention is also a dosing device 5 as such, whose control unit 8 is programmed so that the method steps described above can be carried out.

Claims (10)

1. A method for controlling a dispensing device (5) of a stand-alone dispensing system for flowable detergents or cleaning agents preferably for use in a dishwasher,
   whereby the dispensing system (4) consists of the dispenser (5) and a storage container for at least one detergent or cleaning agent, especially embodied as a cartridge (11) coupled removably to the dispenser (5),
   whereby the dispenser (5) has a housing (6), in the housing (6) has at least one energy source (7), at least one actuator (16) for carrying out a dispensing, and an electronic control unit (8) for controlling at least one actuator (16), and on the housing (6) has a conductivity sensor (18), which is connected to the control unit (8) in terms of circuity and is outwardly open to the surroundings of the dispenser (5),
   characterized in that
   during the running of a cleaning cycle with at least two different rinse stages (S₁, S₂), the measured conductivity value (L), currently detected by the conductivity sensor (18), is determined continuously or discontinuously by the control unit (8),
   the sequence of determined measured conductivity values (L) is evaluated by the control unit (8) with respect to the course of the absolute value of the conductivity (L) and with respect to the gradient of the course (dL/dt) of the conductivity, and
   when the currently measured conductivity value (L) falls below a maximum measured conductivity value (L_max) determined in the first rinse stage (S₁) and the gradient of the course (dL/dt) of the measured conductivity values exceeds a certain threshold (D), this is evaluated by the control unit (8) as a water change and the start of the next rinse stage (S₂).
2. The method according to claim 1, characterized in that
   when after the start of a second rinse stage (S₂), it is again detected by the control unit (8) that the gradient of the course (dL/dt) of the conductivity exceeds the threshold (D) or another threshold (D') stored for the second rinse stage (S₂), this is evaluated by the control unit (8) as a water change and the start of the next rinse stage (S₃).
3. The method according to claim 2, characterized in that
   a minimum measured conductivity value (L_min) is predefined in the control unit (8) or determined and stored by the control unit (8) and
   it is evaluated by the control unit (8) as the start of the last rinse stage (S₃), the final rinse stage, only when in addition the minimum measured conductivity value (L_min) is undershot.
4. The method according to claim 3, characterized in that
   the minimum measured conductivity value (L_min) is determined and stored by the control unit (8) at the start of the first rinse stage (S₁) of the cleaning cycle.
5. The method according to claim 3, characterized in that
   the minimum measured conductivity value (L_min) is determined and stored by the control unit (8) during the change from the first rinse stage (S₁) to the second rinse stage (S₂) of the cleaning cycle.
6. The method according to one of claims 3 to 5, characterized in that it is evaluated by the control unit (8) as the start of the last rinse stage (S₃), the final rinse stage, only when the minimum measured conductivity value (L_min) is undershot and is again exceeded by the currently measured conductivity value (L) within a predefined time window after the undershooting of the minimum measured conductivity value (L_min).
7. The method according to one of the preceding claims, characterized in that at least 100, preferably at least 200, conductivity measurements or resistance measurements are made per second by the control unit (8) by means of the conductivity sensor (18).
8. The method according to one of the preceding claims, characterized in that a polarity reversal occurs at the conductivity sensor (18) after each conductivity measurement or each specific number of conductivity measurements.
9. The method according to one of the preceding claims, characterized in that the control unit is a program-controlled electronic control unit (8) and the process steps are executed or initiated by the program of the control unit (8).
10. A dispenser for a stand-alone dispensing system (4) for a flowable detergent or cleaning agent, preferably for use in a dishwasher,
    having a housing (6), in the housing (6) at least one energy source (7), at least one actuator (16) for carrying out a dispensing, and an electronic control unit (8) for controlling at least one actuator (16), and on the housing (6) a conductivity sensor (18), which is connected to the control unit (8) in terms of circuity and is outwardly open to the surroundings of the dispenser (5),
    characterized in that
    the control unit (8) of the dispenser (5) is programmed so that during operation of the dispenser (5) it executes or initiates the process steps of a method according to one of claims 1 to 9.

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