CN107407034A - For running the method and washing machine of the washing machine with electrochemical sensor - Google Patents

Abstract

The present invention relates to a kind of method for being used to run washing machine (1), with electrochemical sensor (9), the control device (8) for being used to measure electrochemical signals related to container (2) waterborne liquid (7) composition in container (2), the roller (3) for receiving washings (4), roller (3) drive motor (5), container (2), (a) provides in container (2) contains detergent waterborne liquid (7)；(b) roller (3) rotary motion is made according to predetermined movement program；(c) terminate roller (3) rotary motion and make containing detergent waterborne liquid (7) steadily until presetting plateau containing detergent waterborne liquid (7)；(d) by using control device (8) between electrochemical signals and detergent concentration correlation receive analysis electrochemical sensor (9) electrochemical signals, measuring process (a) waterborne liquid (7) detergent concentration c_ten.The present invention relates to a kind of washing machine (1) for being adapted for carrying out methods described.

Description

Method for operating a washing machine with electrochemical sensors and washing machine

technical field

The invention relates to a method for operating a washing machine with an electrochemical sensor and a washing machine suitable therefor. The invention relates in particular to a method for operating a washing machine having a container, a drum for receiving laundry, a drive motor for the drum, a water-based liquid in the container for determining and in the container ( Flüssigkeit) electrochemical sensors for composition-dependent electrochemical signals, and control devices, and to a washing machine suitable for carrying out the method.

Background technique

In washing machines, the laundry is usually treated in a washing phase for cleaning with a washing lye containing detergent. Furthermore, after a rinsing phase with water in which washing lye and/or contaminants are removed in or on the laundry, the laundry is usually treated with a softener. Here, for reasons of cost and environmental protection, it makes sense to use optimal amounts of laundry treatment agents (especially detergents and softeners). Overdosing should be avoided but at the same time underdosing should be avoided. In particular, bubbling over (overdosing) or poor wash performance (underdosing) can result due to incorrect dosing of detergent. In order for this not to happen, it is desirable to monitor and optimally adjust the detergent concentration.

Therefore, a washing machine has been proposed which finds an optimal amount of e.g. detergent and can provide a dosing recommendation to the user of the washing machine on a display screen with accurate data on e.g. the amount of detergent to be used .

WO 03/029550 A1 describes a process-controlled domestic refrigerating appliance with a microcomputer and a display for text, in which there is also an Indication area for the amount of necessary additives (eg detergent). The household appliance has a device by means of which, for example, additives can be supplied to the washing process, the dosing of which has to be carried out by the operator.

In order to save detergent, it is expedient to distribute the detergent dosage according to the type and intensity of soiling of the laundry to be washed. In addition to saving energy and water, optimally matching the dosing of detergent to a batch of laundry also results in a lower load of waste water, among other things.

DE 29 17 859 describes a method for monitoring and controlling programs, in particular water injection and/or detergent addition or rinse agent addition, in automatic washing machines and dishwashing machines, wherein the washing machine is set in the machine Sensors that respond to the surface tension and/or water hardness and/or conductivity of the liquid are embedded in the program flow through the control circuit and control the dosing of water filling, water changes and/or detergent addition or rinse agent addition .

EP 2 533 035 A1 describes a device for detecting material properties of a medium, said device having a measuring device comprising a sensor device in connection with the medium, and said device having a device for determining by a predetermined The signal of the frequency range regulates the control device of the sensor device, and the device has a control device for controlling the operation of the measuring device and predefining the predetermined frequency range, wherein the control device is provided for determining the impedance Z of the medium corresponding According to the change curve of the frequency range predetermined according to the frequency and for outputting the detection signal, and the control device is set for analyzing and processing the detection signal of the control device and determining the change curve of the impedance Z. points (P1 to P4) and generate a resulting signal about the properties of the medium. Thus, for example, it should be possible to determine whether the washing lye requires further addition of detergent.

EP 2 767 825 A1 describes a method and an apparatus for determining the micelle formation concentration (Mizellbildungskonzentration). The method is carried out in a washing device having the necessary water quantity for carrying out the washing process, the method having the steps of:

- supplying part of the quantity of detergent to the quantity of water to constitute the washing lye (step 1),

- detection of the magnitude Z and phase angle of the impedance of the washing lye for a predetermined number of frequencies of the control signal and generate corresponding quantities of corresponding measured values (step 2),

- finding the slope from the individual measurements of the phase angle (step 3),

- calculation of the corresponding measured value from the amount of slope and the magnitude of the impedance (step 4),

- determining the product MBP from the mean value of the slope and the mean value of the magnitude of the impedance (step 5B),

- comparing the determined product with a predetermined threshold (step 6B), and

- Repeat steps 1 to 6B until the product is determined to be equal to or greater than the threshold (XB) (step 7).

To monitor the concentration of detergent or other additives in the aqueous liquid in the lye container, optical or electrochemical sensors are usually used, for example turbidity sensors, impedance sensors. It must be taken into account here that, in order to form the washing lye for cleaning the laundry, the detergent comprises in particular a surfactant as a surface-active substance, wherein the surfactant reduces the amount of water in the formed aqueous solution (washing lye). The surface tension of the water in , since the surfactant preferably adsorbs on the surface and at the same time adsorbs on the contact surface. That is to monitor especially the surfactant concentration in the aqueous liquid in the lye container.

The signal of the sensor can be distorted and, when the aqueous liquid to be measured is not sufficiently smooth and/or there is too much foam in the aqueous liquid, the signal of the sensor can only be poorly or generally not recognized. Analytical processing. Especially when the impedance sensor is used as an electrochemical sensor, this can lead to no analytically manageable results.

EP 0 383 218 B1 describes a method for controlling the rinsing of a program-controlled washing machine, which carries out a plurality of rinsing programs following a washing process, wherein the conductivity of the rinsing water is measured and, when measured The rinsing is terminated when the difference between the conductance and the reference conductance falls below a predetermined value, wherein the conductance measurement is carried out in the section of the discharge pipe in which, after emptying the washing machine chamber, there is still liquid, and, after completion of the rinsing process, a conductometric measurement is carried out on the rinsing water located in the section, and a decision is made on the basis of the result of the conductometric measurement whether to carry out a further rinsing process. Here, the conductivity measurement is preferably carried out in a smooth pump sump.

Contents of the invention

Against this background, the object of the present invention is to provide a method for operating a washing machine which is improved with regard to the measurement of electrochemical signals, in particular impedance signals of an impedance sensor. In this case, it is preferred that the monitoring of the washing program be as simple and/or accurate as possible. Furthermore, the object of the invention is to provide a washing machine which is suitable for carrying out such a method.

According to the invention, this object is solved by a method and a washing machine according to the independent claims. Preferred configurations of the invention are set out in the corresponding subclaims. Preferred configurations of the method correspond to preferred configurations of the washing machine, even if they are not individually indicated here.

Accordingly, the present invention relates to a method for operating a washing machine having a container, a drum for receiving laundry, a drive motor for the drum, a device in the container for measuring and a water property in the container. Electrochemical, and control device for electrochemical signals related to the composition of liquids, wherein the following steps are performed:

(a) providing an aqueous liquid containing detergent in a container;

(b) rotating the drum according to a predetermined program of motion;

(c) ending the rotary motion of the drum and stabilizing (Ruhenlassen) the aqueous detergent-containing liquid until a predetermined stationary state (beruhigter Zustand) of the aqueous detergent-containing liquid is reached; and

(d) measuring the electrochemical signal provided in step (a) by receiving and analyzing the electrochemical signal of the electrochemical sensor using the correlation between the electrochemical signal and the detergent concentration stored in the control device The concentration c _ten of the detergent in the detergent-containing aqueous liquid.

Here, the term "aqueous liquid containing detergent" is to be interpreted broadly. Here, detergent means detergent itself, including its ingredients surfactants, enzymes, bleaching agents, etc., and softening agents. Furthermore, the detergent-containing aqueous liquid can also be referred to as washing lye, eg free rinse liquid or rinse liquid, depending on the phase in the washing program in which the detergent-containing aqueous liquid accumulates.

Furthermore, within the meaning of the present invention, a container is understood to be an lye container, a part of a container or a component part in which or next to which the aqueous liquid is supplied during operation of the washing machine flow through. Thus, the impedance sensor can be arranged in the lye container of the washing machine and in the measuring container or in the liquid line, which is connected in communication with the lye container, through which the aqueous liquid passes during the operation of the washing machine. Liquid pipeline flow. This can be particularly advantageous when the washing machine has a circulating pump system which removes the aqueous liquid from the lye container and supplies it again to the lye container during the operation of the washing machine.

As a measure of the predetermined plateau, for example, the contribution of convection to the transport process in the aqueous liquid can be taken into account.

In order to determine a sufficiently stationary state of an aqueous liquid, one can consider the case where various electrochemical measurement methods generate an electrochemical signal in the quiescent state of the aqueous liquid, the Faradaic electrolysis part of the electrochemical signal being passed through the electroactive The diffusion (Diffusion) of the grain species (elektroaktiven Spezies) is determined. If the aqueous liquid is not at rest, the transport of electroactive species to the electrodes is no longer caused solely by diffusion, but also by convection. This usually results in a characteristic change in the electrochemical signal, where the change is a measure of the contribution to the flow. Thus, by analytically processing the electrochemical signal it is possible to infer a convective contribution and thus an aqueous liquid which may not be sufficiently stationary. Suitable electrochemical signals can be measured, for example, by means of voltammetric methods. Such electrochemical signals can be obtained, for example, by using cyclic voltammetry, amperometry or double pulse amperometry, but also by impedance spectroscopy.

In cyclic voltammetry, starting from the starting voltage, the voltage at the working electrode of the electrochemical sensor is changed at a generally constant rate up to the so-called reversal voltage U _λ (the so-called "forward sweep (Hinsweep)"), which The reversal voltage is sufficient for oxidation or reduction processes. Subsequently, the direction of the voltage change is reversed and the voltage is changed again towards the starting voltage (“sweep back”). The current occurring here generally increases to the peak value I _p during the forward scan, and then falls to the value I _{λ up to the reversal potential U λ .} In this context, the proportionality I _p /I _λ is usually the characteristic variable I _p /I _λ ^theor in the case of diffusion control of the electrode operating process. If the solution to be examined by voltammetry is in motion, this means that convection currents are present, which generally lead to a decrease in I _p /I _λ . Consequently, the then measured value I _p /I _λ ^real or the difference ΔI = I _p /I _λ ^theor - I _p /I _λ ^real can generally be used as a measure of the contribution of convection and thus of the steady state of the aqueous liquid considered and used.

In amperometry, a voltage step is usually carried out to a suitable voltage, which is sufficient for oxidation and reduction processes, and the current reduction is then measured and evaluated as a function of time. In this case, the contribution of the convection usually leads to an attenuation of the current reduction. In double-pulse amperometry, a jump is then made to the starting voltage and at the starting process voltage the current reduction is again measured and evaluated as a function of time.

Therefore, in a preferred embodiment of the method according to the invention, the current-voltage curve is plotted in step (c) as a measure of the plateau and not the current fraction caused by the diffusion to the electrochemical sensor for analytical processing.

Particularly advantageously, for this purpose, a cyclic voltammogram (Cyclovoltammogramm) is plotted and, with respect to the current fraction not caused by diffusion to the electrochemical sensor, the peak current when scanning forward to the reversal potential U _λ I _p as well as the current I _λ at the reversal potential U _λ are analyzed.

Alternatively or in addition to this, a potential step can be carried out using an electrochemical sensor and the current-time curve obtained here can be evaluated with respect to the fraction not caused by diffusion as a stationary state for the aqueous liquid (i.e. lack of stationary) measure. Here, a potential step is carried out, in particular to a potential at which constituents in the aqueous liquid are reversibly or irreversibly oxidized or reduced.

If the potential change at the electrochemical sensor is mentioned here, it means in particular the potential change at the working electrode of the electrochemical sensor forming the electrochemical sensor. Correspondingly, refers to: diffusion and convection with reference to the transport of species to the working electrode.

In a particularly preferred embodiment of the method according to the invention, the detergent-containing aqueous liquid is stabilized for a predetermined period of time Δt _set in step (c). Here, the amount of aqueous liquid, the load of laundry and/or the motion program executed in step (b) is preferably taken into account for determining Δt _set , wherein the time period Δt _set already stored in the control device is taken into account , the amount of aqueous liquid, the amount of laundry and/or the correlation between the exercise program performed in step (b).

The amount of aqueous liquid can be ascertained, for example, by measuring the amount of water introduced into the container by means of a water quantity counter, wherein the portion of the introduced water absorbed by the washing can be taken into account, and when, for example, a hydrostatic pressure is arranged in the container When using a pressure sensor for measuring the hydrostatic pressure as a measure for the free rinsing fluid, a so-called free rinsing fluid can be ascertained.

The laundry load can be adjusted by the user, or can however preferably be determined automatically in the washing machine. Here, the determination of the load can be carried out by measuring the weight increase of the drum due to the load of the laundry, or however also by analyzing the suction properties of the water by adding water to the dry laundry During the above period, the change of the hydrostatic pressure is analyzed. For this purpose, a hydrostatic sensor is advantageously provided in a washing machine according to the invention. Particularly advantageously, a water quantity counter is also provided, ie a measuring device for ascertaining the quantity of water or lye supplied. Thus, for example, the hydrostatic pressure p measured by means of the hydrostatic sensor can be compared with the filled water quantity. The laundry in the drum absorbs water. The absorbed water may not contribute to the increase in hydrostatic pressure. By comparing the measured hydrostatic pressure p and the injected water quantity - both in absolute value and its change over time - with the corresponding values stored in the washing machine's control unit for the saturation of the laundry, it is possible to find The load of the laundry and, if necessary, its degree of saturation (wetness) can be determined.

In another preferred embodiment, in order to stabilize the aqueous detergent-containing liquid until a predetermined plateau of the aqueous detergent-containing liquid is reached, the effect of the electrochemical signal on the existing amount of foam or concentration dependence. In this case, the presence and amount of foam can be ascertained in different ways.

For example, the detection of suds in a washing machine can be carried out by conductometric measurement using two electrodes in the lower region of the container. In addition, foam detection can be carried out during drum centrifugation by means of the evaluation of the setpoint/actual rotational speed difference. Here, use is made of the fact that the foam can brake the rotating drum, resulting in a difference between the setpoint speed and the actual speed. In this case, the association between the determined foam concentration and the target/actual rotational speed difference is usually stored in the control unit of the washing machine. Usually, the presence of foam (liquid-air mixture) is detected by the pressure build-up during washing or spinning or by a strongly reduced pressure drop during pumping.

Usually, in order to detect the formation of foam, the pressure of the hydrostatic pressure in the container is measured by means of sensors. For this purpose, pressure sensors, in particular hydrostatic pressure sensors, are usually used which, as explained above, are also suitable for determining the water level in the container. Here, by pretending to be False pressure rises leading to measurement errors. The presence of foam is indicated by the appearance of pressure peaks, even if no foam is present. This is attributable to fluctuations in the pressure measurement by means of the sensor, errors in signal reception, signal conversion or signal processing also being dependent on whether a digital or analog controller is used. Because the occasional negative value will not be detected by the sensor, the true average value cannot be obtained (if the negative part can be detected, the true average value may be obtained), and the value of the oscillating water volume can be obtained. Increased pressure. Furthermore, the signal measured by the pressure sensor increases with the rotational speed, so that the pressure threshold predetermined for detecting foam is exceeded prematurely. Thus, advantageously, suds in a washing machine can be detected by measuring the signal _Sn by a sensor for determining the signal of liquid located in the container and possibly containing suds during the rotation of the drum at a high rotational speed _Un and by It is compared with the value W _n corresponding to this rotational speed U _n stored in the program control device, wherein the value pair U _n and W _n (n≧1) is stored for at least two rotational speeds in the control device, Also, the presence of foam is recorded when the value W _n is reached or exceeded (ie when the condition S _n ≥ W _n is satisfied). Here, however, the sensor can be an optical measuring system, a measuring system for measuring conductivity or a measuring system for capacitance. Preferably a hydrostatic pressure sensor, in which the hydrostatic pressure p and/or the negative gradient of the hydrostatic pressure over time (dp/dt) are preferably measured as a signal, the container The preferred hydrostatic pressure p of the liquid-air mixture in . The signal S _n and the corresponding value W _n are especially pressure values.

Therefore, in a preferred embodiment of the method according to the invention, the presence of foam in the aqueous liquid is ascertained with a hydrostatic pressure sensor and taken into account for determining the steady state of the aqueous liquid.

In addition, the presence of foam is also manifested in the electrochemical signal. That is, if the foam is in front of the electrodes, the measured current typically decreases. Therefore, the amount and duration of this sudden current reduction can be taken into account as a measure for the presence of foam, wherein the time interval Δt (also called "reversing pause" or "roller pause") for smoothing can be extended appropriately. stage") until the foam density returns to acceptable values.

The method used to detect suds usually depends on: at which stage of the washing program (i.e. especially in the soaking, washing, rinsing or softening phase) should it be ensured that the aqueous solution is sufficiently stable to be able to receive effective electrochemical signal.

If a pressure sensor (especially a hydrostatic pressure sensor) is present in the washing machine used, the pressure increase measured during the plateau phase (i.e. the drum standstill phase) due to aqueous liquid dripping from the laundry can also be taken into account as A stable measure for aqueous liquids. That is, as time increases, the amount of dripped liquid decreases.

According to the invention, when a predetermined time period Δt _set is specified, it can advantageously be provided to check with the aid of the electrochemical sensor whether a sufficient stabilization of the aqueous liquid actually takes place. This can be done, as mentioned above, by ascertaining the convective-induced fraction of the mass transport to the working electrode. If this is not the case, the predetermined time period Δt _set can be adjusted and in particular extended. In this case, it can advantageously be provided that a maximum time period Δt _set ^max is not exceeded. When Δt _set ^max is reached or exceeded, the movement program of the drum is advantageously adjusted and in particular the introduction of mechanical energy is reduced. This makes it possible to achieve that no too long periods of time are required for the rotation pauses of the drum.

The introduction of mechanical energy takes place by means of a suitable movement program of the drum. The movement program in step (b) of the method according to the invention includes in particular the switch-on time [in %], the duration of the reversing cycle [in seconds] and the rotational speed of the drum [rev/min]. The switch-on time is the portion of time of a phase of the washing program during which the drum rotates. This on-time is preferably 60% to 70%, for example in the first rinsing step. A reversing cycle is generally a period of time that results from a period of time when the drum rotates in one direction, the drum is stationary, the drum rotates in the opposite direction, and the drum is stationary.

For a sufficiently smooth determination and especially a confirmation of the predetermined time period Δt _set , it is also advantageous to consider the type of electrochemical measurement method used in step (d), because the electrochemical measurement method may require an aqueous liquid Different measurement times and resting states.

The reception of electrochemical signals is particularly accurate when relatively little contamination and/or foam is present in the aqueous liquid to be examined. This is especially the case during the wetting phase and during the rinsing phase. Accordingly, in a preferred embodiment of the method according to the invention, steps (c) and (d) are carried out in the wetting phase and/or in the rinsing phase.

Here, the soaking phase is understood to be the phase in the washing program in which the laundry to be cleaned and in particular to be washed with washing lye is moistened with the washing lye used for this, usually until the washing until the substance is saturated with washing lye. Here, the laundry usually moves only slightly or not at all. Therefore, usually only a small separation of the pollutants from the laundry to be washed takes place in the wetting phase. In particular, the laundry drum preferably does not rotate at more than 25 revolutions per minute during the wetting phase. Here, "washing lye" and "aqueous liquid containing surfactant" generally have the same meaning. The term "surfactant" as used herein denotes a single surfactant as well as mixtures of different surfactants.

The degree to which the aqueous liquid is moved by the movement program and thus the subsequent drum standstill phase is necessary also depends on the presence and shape of the laundry carriers in the drum. If the shape of the laundry carrier is asymmetrical, its contribution to the movement of the aqueous liquid depends on the direction of rotation at a predetermined rotational speed of the drum. Thus, in the case of an asymmetrical shape of the laundry carrier used in the drum, at least the direction of rotation of the drum before the drum standstill phase is taken into account.

According to the invention, step (c) and/or step (d) are preferably carried out taking into account the type and/or amount of contamination of the laundry, wherein in the control device different types of contamination and/or The amount of contamination stores the correlation between the electrochemical signal and the detergent concentration.

For example, in the case of contamination by oil, it can result that especially nonionic surfactants can dissolve more or less significantly in the oil and can no longer be detected when measuring the detergent concentration. On the other hand, ionic surfactants can be intercepted (ie, consumed) by ion-containing contaminants to such an extent that they are no longer detected when measuring electrochemical signals.

The type of soiling and/or the amount of soiling can be adjusted and set by the user of the washing machine, or can however be measured by suitable sensors. Electrochemical sensors provided according to the invention, for example impedance sensors, are also particularly suitable for this. In addition, other sensors such as, for example, turbidity sensors can of course also be used in addition.

Electrochemical sensors are generally electrode systems consisting of at least two electrodes. The potential at the working electrode, which is responsible for receiving the electrochemical signal here, can be adjusted particularly precisely using a three-electrode arrangement consisting of a working electrode, a counter electrode and a reference electrode.

In any case, according to the invention, a single electrode system can be used for receiving different electrochemical signals, i.e. for example for cyclic voltammetry or impedance spectroscopy in which the electrical Chemical sensors are also called impedance sensors. According to the invention, electrochemical sensors are preferably used in step (d) as impedance sensors. Here, the impedance sensor receives the impedance signal as an electrochemical signal.

In the method according to the invention, the reception and evaluation of the impedance signal is generally carried out by loading the impedance sensor with an alternating voltage with a varying frequency and determining the phase angle of the impedance The impedance signal is analyzed and processed quantitatively. The phase angle of the process impedance can then be analyzed in terms of the detergent, especially the type, amount and concentration of the surfactant and also the micellar concentration and magnitude.

For the measurement, an impedance spectrum is usually taken by using a suitable electrode system as an impedance sensor. Here, the impedance of the electrochemical system is checked as a function of the frequency of the alternating voltage at the working electrode. For illustration, the person skilled in the art knows various diagrams, such as for example a Nyquist diagram, in which the real or imaginary part of the impedance is shown depending on the frequency of the alternating voltage used. When examining washing lye, usually several characteristic points are suitable for characterizing the impedance spectrum (compare EP 2 767 825 A1), for example the point with the imaginary part at the maximum value in the lower frequency range or the imaginary part at The point on the minimum in the upper frequency range. For aqueous liquids containing detergents, typical parameters can usually be derived from impedance and frequency values at characteristic points. For example, the conductivity of the liquid can be determined from the real part of the point. In general, by evaluating the impedance at this point and the frequency at another point, the capacitance of a so-called conductivity measuring cell formed by the impedance sensor and the washing lye can be determined. Another variable relevant to the properties of the washing lye is the smoothness of the semicircle in the Nyquist diagram, which can be determined via the ratio of the height of the semicircle to its width. Analytical processing is performed by using formulas known to those skilled in the art.

In a particularly preferred embodiment of the invention, the impedance signal is evaluated with respect to the conductance as a measure of the water hardness of the aqueous liquid.

Therefore, according to the invention, the impedance signal is preferably received by an impedance sensor, wherein the acquisition and evaluation of the impedance signal is carried out by loading the impedance sensor with an alternating voltage with a varying frequency and determining the phase angle of the impedance The impedance signal is analyzed and processed in terms of magnitude and magnitude. Here, it is particularly preferred that the acquisition of the impedance signal is carried out at a predetermined frequency of the alternating voltage.

The washing phase is usually followed by the wetting phase. Usually, if the washing program signals that there is sufficient wetting of the laundry, for example, by reaching a predetermined threshold value p ₁ for the hydrostatic pressure p and a predetermined pressure p for the hydrostatic pressure At the threshold of the gradient in time (Δp/Δt) ₁ , the washing phase begins. Especially during the washing phase, it is of interest to monitor the detergent concentration with electrochemical sensors. From this, the consumption of detergent and thus a possible need for additional dosing of laundry can be determined. Furthermore, the washing program can be optimally adapted to the determined detergent concentration.

Furthermore, the object of the present invention is a washing machine with a container, a drum for receiving laundry, a drive motor for the drum, an electric sensor in the container for measuring the composition of the aqueous liquid in the container. An electrochemical sensor for a chemical signal, and a control device, wherein the control device is configured to perform a method comprising the following steps:

(a) providing an aqueous liquid containing detergent in a container;

(b) rotating the drum according to a predetermined program of motion;

(c) ending the rotary motion of the drum and stabilizing the detergent-containing aqueous liquid until a predetermined plateau of the detergent-containing aqueous liquid is reached; and

(d) measuring the electrochemical signal provided in step (a) by receiving and analyzing the electrochemical signal of the electrochemical sensor using the correlation between the electrochemical signal and the detergent concentration stored in the control device The concentration c _ten of the detergent in the detergent-containing aqueous liquid.

According to the invention, a washing machine is preferred, in which a temperature sensor is arranged in the container and electrochemical signals (for example impedance signals) and washing Interrelationships between dose concentrations.

According to the washing machine realization of the present invention, the turbidity sensor usually present in the washing machine is omitted. Of course, in some embodiments of the washing machine according to the invention, a turbidity sensor can additionally also be provided.

Usually, the washing machines used here also have a heating device and a lye discharge system arranged on the floor of the lye container with a lye pump. Furthermore, the washing machines used here usually also have a laundry carrier and/or a suction device

Finally, the washing machine according to the invention may be a washing machine itself or a washing-drying machine (ie an appliance having the functions of a dryer and a washing machine).

Preferably, the washing machine according to the invention has an acoustic and/or optical display device for displaying one or more operating states. The optical display means can be, for example, a liquid crystal display on which certain requests or instructions are indicated. Additionally or alternatively, the light emitting diodes can flash in one or more colors. For example, it can be indicated on the basis of the color-coded diagram whether the washing phase was run with an optimal detergent concentration. Furthermore, it can also be indicated whether the measurement is carried out by means of an electrochemical sensor in a sufficiently stationary aqueous liquid.

In the case of insufficient detergent dosage, a reminder can be given to the user of the washing machine: to increase the dosage of detergent, wherein the quantity regulation can also be carried out here. In this case, the display of the dosage recommendation takes place on the display itself or on its display field (here generally referred to as “display”).

The dosage recommendation can be shown in text and/or symbolic form on the display. A suitable text could be, for example, the direct request "Please dose "Green"", wherein "Green" is a reminder for the dosing aid. It is also possible to list other colors or to give other hints in text form. As an alternative or in addition to this, colors or symbols can be displayed as symbols, for example circles, which can be filled in each case to different degrees in order to distinguish individual detergent quantities.

Knowing the amount of water or water lye flowing into the container is significant in embodiments of the present invention. Therefore, preferably in the washing machine according to the invention there is a measuring device for ascertaining the filled water quantity, for example a time measuring device for determining the opening period of the filling valve for water or for measuring the filled water quantity liquid volume measuring equipment.

The present invention has numerous advantages. A method is provided for operating a washing machine, in which method the concentration of detergent, for example in a washing lye, is monitored particularly accurately by means of an electrochemical sensor, in particular an impedance sensor. According to the invention, this is achieved in such a way that it is taken into account that if the solution is not sufficiently stationary at the time of the measurement, it may disturb the electrochemical measurement and in particular the measurement of the impedance signal by means of the impedance sensor and thus the measured Impedance signal is distorted. The invention achieves, inter alia, by adapting the intervals when the drum is reversed during wetting, washing and rinsing, mainly by impedance measurements and cycles with the aid of electrochemical sensors in aqueous liquids containing detergents, especially surfactants. Voltammetry accurately determines surfactant concentration and water hardness and avoids erroneous measurements due to air bubbles, foam and flow contained in aqueous liquids.

Through the more accurate ascertainment of the actual detergent concentration and the associated measures during the washing program, an overdosing or underdosing of detergent can be influenced in good time. On the one hand, it can prevent the washing machine from bubbling and overflowing The bubbling overflow may be associated with water damage in a residence. On the other hand, excessive use of rinse water, which may be necessary if excess detergent has to be removed from the laundry, can be avoided. It also allows, for example, to more accurately determine the concentration of ionic surfactants and to adjust and maintain the concentration range for ionic surfactants more precisely.

Description of drawings

The invention is explained below with reference to a non-limiting embodiment for a washing machine according to the invention shown in the single drawing. A schematic representation of a first embodiment of a washing machine according to the invention, in which the method according to the invention can be carried out, is shown in a schematic illustration of the essential parts of the invention.

detailed description

The washing machine 1 of the drawing has a lye container 2 in which a drum 3 is rotatably mounted and can be driven by a drive motor 5 . In order to achieve improved ergonomics, the axis of rotation 19 of the drum 3 is oriented upwardly and frontally at a small angle (eg 13°) from the horizontal, so that the user of the washing machine 1 can reach and see inside the drum 3 more easily. In addition, this arrangement also achieves a counter-use of the washing lye in cooperation with the laundry carrier 14 on the inner surface of the drum shell and the suction device 17 for the aqueous liquid containing detergent, for example the washing lye 7 . 7 Intensification of soaked laundry 4. In the embodiment shown here, the laundry carrier 14 is asymmetrical, so that for the two possible directions of rotation of the drum 3 the lye container 2 is The aqueous liquid 7 in moves with different ranges of action (Ausmaβ). This influence is taken into account in the control unit 8 so that the method according to the invention can be carried out even more precisely.

Impedance sensor 10 is arranged in plunger housing 12 as an electrochemical sensor, usually an electrode system consisting of a plurality of electrodes, for example two capacitor plates or a three-electrode arrangement. The detergent present in the rinsing housing 12 or the aqueous liquid containing it can be analyzed by means of the impedance sensor 10 in order to obtain information about the detergent and at the same time about the design of the washing program.

Furthermore, the washing machine 1 has a lye filling system comprising a water connection for the domestic water network 20, an electrically controllable valve 21 and a supply line 13 to the lye container 2, which is optionally It is also possible to lead through the detergent rinsing housing 12 , from which the water to be injected can transport a portion of the detergent into the lye container 2 . Furthermore, a heating device 16 for heating the water or washing lye 7 is located in the lye container 2 . The valve 21 as well as the heating device 16 can be controlled by the control device 8 according to a program schedule, which can be combined with a time program and/or to achieve e.g. the level of lye inside the washing machine 1, the temperature of the lye, the rotational speed of the drum And so on in combination with certain measured values of such parameters.

6 denotes a pressure sensor in the lye container 2 , ie a sensor for measuring the hydrostatic pressure. The hydrostatic pressure p results from the level of free rinsing liquid 7 formed in the lye container 2 . Furthermore, the washing machine 1 comprises a measuring device 15 for ascertaining the quantity of filled water, for example a water quantity counter or a flow meter. In the case of a flow meter, the inflowing water quantity is calculated in conjunction with the detected filling time. The flow rate can also be determined by measuring the time until a predetermined level is reached, which corresponds to the determined fixed water quantity. 18 represents the lye pump for pumping out washing lye 7.

In the drawing, 9 denotes an electrochemical sensor in the lye container 2 , by means of which various electrochemical measurements, such as voltammetry or impedance measurements, can be carried out. The electrochemical sensor is preferably used as an impedance sensor, wherein the structure of the sensor consisting of electrodes and the execution and evaluation of the impedance signal measured by the impedance sensor are not shown in detail here. In order to implement the method according to the invention, the electrochemical signals of the electrochemical sensor 9 and possibly the impedance sensor 10 as well as the rotational speed of the drum 2, the loading of the laundry 4, the pressure of the hydrostatic pressure etc. and the measured values of the measuring device 15 are provided to the control unit 8.

Here, execution according to the method of the present invention comprises the following steps:

(a) providing an aqueous liquid 7 containing detergent in the lye container 2;

(b) Rotate the drum 3 according to a predetermined motion program, which may include different reversing steps and centrifugal dehydration steps in the case of different rotation speeds of the drum 3 according to the soaking phase, washing phase or rinsing phase wait;

(c) ending the rotary motion of the drum 3 and making the detergent-containing aqueous liquid 7 stable until a predetermined steady state of the detergent-containing aqueous liquid 7 is reached; and

(d) by receiving and analyzing the electrochemical signal of the electrochemical sensor 9 using the correlation between the electrochemical signal and the detergent concentration already stored in the control device 8, thereby measuring the The concentration c _ten of the detergent in the detergent-containing aqueous liquid 7 provided in .

In step (c), the stabilization of the detergent-containing liquid 7 is preferably monitored by means of an electrochemical sensor 9, wherein, in order to determine the predetermined steady state of the aqueous liquid 7, preferably by means of cyclic voltammetry, amperometry Or impedance spectroscopy performs the measurement.

In step (d), in the embodiment shown here, the concentration c _ten of the detergent in the detergent-containing aqueous liquid 7 is measured by receiving and analyzing an electrochemical sensor acting as an impedance sensor 9 9, wherein the correlation between the impedance signal and the detergent concentration already stored in the control device 8 is used.

11 denotes a display device, by means of which method parameters can be displayed, especially in the case of optimal use of detergent (for example, can be shown by a green light-emitting diode) or in the case of non-optimal use of detergent (for example The progress of the washing program can be shown by the red LED). In particular, dosage recommendations can also be displayed to the user of the washing machine.

List of reference signs

1 washing machine

2 lye containers

3 rollers

4 laundry

5 drive motor

6 pressure sensor

7 Aqueous liquids, free rinses, washing lye

8 Controls

9 Electrochemical sensors in lye tanks, e.g. impedance sensors; electrode arrangement for measuring impedance

10 Impedance sensor in flush housing; electrode arrangement assembly for measuring impedance

11 display device

12 (detergent) flush into case

13 Inlet to lye container

14 laundry carrier

15 Measuring device for determining the quantity of water charged

16 heating device

17 Extraction device

18 pumps, lye pumps

19 Axis of rotation

20 Water inlet pipe, domestic water network, water supply device

21 (electrically controllable) valves

22 temperature sensor

Claims (15)

1. one kind is used for the method for running washing machine (1), the washing machine has：

- container (2),

- be used to receive the rollers (3) of washings (4),

- the drive motor (5) for the roller (3),

Electrochemical sensor (9) in-container (2), the electrochemical sensor are used to measure and the water in the container (2) Property liquid (7) the related electrochemical signals of composition, and

- control device (8),

Characterized in that, perform following steps：

(a) waterborne liquid (7) containing detergent is provided in the container (2)；

(b) according to predetermined motor program, rotate the roller (3)；

(c) terminate the rotary motion of the roller (3), and make the waterborne liquid (7) containing detergent steadily, until reaching Contain the previously given plateau of the waterborne liquid (7) of detergent to this；With

(d) concentration c of the detergent in the waterborne liquid (7) containing detergent provided in the step (a) is measured_ten, its Mode is, using the correlation being stored between in the control device (8), electrochemical signals and detergent concentration In the case of, the electrochemical signals of the electrochemical sensor (9) are received and analyzed and processed.

2. according to the method for claim 1,

Characterized in that,

As the measurement to plateau, in the step (c), electric current electricity is received by the electrochemical sensor (9) Buckle line, also,

To the i-v curve on not being by diffusing to the electric current share side caused by the electrochemical sensor (9) Face is analyzed and processed.

3. according to the method for claim 2,

Characterized in that,

A cyclic voltammetry curve figure is received, also,

To in scanning forward to reverse potential U_λWhen and reverse potential U_λThe peak point current I at place_pOn not being by diffusing to Analyzed and processed in terms of electric current share caused by the electrochemical sensor (9).

4. according to the method in any one of claims 1 to 3,

Characterized in that,

In the case of using the electrochemical sensor (9), potential step is performed, and

The current-time curvel obtained at this is analyzed and processed in terms of not being the share as caused by diffusion, as right The shortage of the waterborne liquid is smoothly measured.

5. method according to any one of claim 1 to 4,

Characterized in that,

In the step (c), with predetermined period Δ t_setMake the waterborne liquid (7) containing detergent steady.

6. according to the method for claim 5,

Characterized in that,

In order to determine period Δ t_set, it is contemplated that：

- waterborne liquid (7) is measured,

- washings (4) is measured, and/or

Performed motor program in the-step (b),

Wherein, it is contemplated that the correlation being stored between the following parameter in the control device (8)：

- period Δ t_set,

- waterborne liquid (7) is measured,

- washings (4) is measured, and/or

Performed motor program in the-step (b).

7. method according to any one of claim 1 to 6,

Characterized in that,

For making the waterborne liquid containing detergent steadily until reaching the advance of the waterborne liquid (7) for containing detergent Given plateau, accounted for according to existing foam volume or consistency of foam.

8. according to the method for claim 7,

Characterized in that,

The presence of foam in waterborne liquid (7) is asked for by hydrostatic pressure sensor (6), and is directed to waterborne liquid (7) determination of plateau and account for.

9. method according to any one of claim 1 to 8,

Characterized in that,

The step (c) and (d) are performed in wetting phase and/or rinse stage.

10. method according to any one of claim 1 to 9,

Characterized in that,

In the case that washings carrying piece (14) employed in the roller (3) has asymmetrical shape, institute is at least considered State direction of rotation of the roller (3) before roller idle periods.

11. method according to any one of claim 1 to 10,

Characterized in that,

In the case where considering the pollution type of the washings (4) and/or contaminant capacity, step (c) and/or step (d) are performed,

Wherein, for the different pollution types and/or contaminant capacity of the washings (4), stored in the control device (8) There is the correlation between electrochemical signals and detergent concentration.

12. the method according to any one of claim 1 to 11,

Characterized in that,

The electrochemical sensor (9) is used in the step (d) as impedance transducer.

13. according to the method for claim 12,

Characterized in that,

Impedance signal is received by the impedance transducer (9), wherein, the reception to the impedance signal and analyzing and processing are performed, Its mode is that the impedance transducer (9) is loaded with the alternating voltage with change frequency, and the impedance is believed Phase angle number on impedanceAnalyzed and processed with terms of value.

14. according to the method for claim 13,

Characterized in that,

In the case where the frequency of the alternating voltage is previously given, the reception to the impedance signal is performed.

15. washing machine (1), the washing machine have：

- container (2),

- be used to receive the rollers (3) of washings (4),

- the drive motor (5) for the roller (3),

Electrochemical sensor (6, the 9) in-container (2), the electrochemical sensor be used to measuring with the container (2) The related electrochemical signals of the composition of waterborne liquid (7), and

- control device (8),

Characterized in that,

The control device (8) is arranged for carrying out a kind of method, the described method comprises the following steps：

(a) waterborne liquid (7) containing detergent is provided in the container (2)；

(b) according to predetermined motor program, rotate the roller (3)；

(c) terminate the rotary motion of the roller (3), and make the waterborne liquid (7) containing detergent steadily, until reaching Contain the previously given plateau of the waterborne liquid (7) of detergent to this；With

(d) concentration c of the detergent in the waterborne liquid (7) containing detergent provided in the step (a) is measured_ten, its Mode is, using the correlation being stored between in the control device (8), electrochemical signals and detergent concentration In the case of, receive and analyze and process the electrochemical signals of the electrochemical sensor (9).