EP3538705B1 - Method for the improved control of a water-conducting domestic appliance, and domestic appliance which is suitable for carrying out the method - Google Patents

Description

The invention relates to a method for operating a water-bearing household appliance with a drum for receiving objects to be treated, which has at least one perimeter with at least one radiation passage, a control device, a spectrometer, which includes at least one radiation source, at least one radiation detector and a microcomputer, wherein Microcomputer and control device are set up to exchange information with each other, so that data can be exchanged between the spectrometer and control device. The invention also relates to a water-bearing household appliance suitable for carrying out this method.

Detergents and cleaning agents are usually used to clean objects in water-bearing household appliances. These detergents and cleaning agents generally have a complex composition since, in addition to washing-active substances, so-called surfactants, they often also contain enzymes, bleaching agents, water softeners and the like. However, the surfactants in particular are of particular importance in the cleaning process, since these compounds reduce the interfacial tension at the water/fat interface, and they therefore make a significant contribution to removing soiling from textiles, for example. In principle, a distinction is made between three types of surfactants, ionic, non-ionic and amphoteric surfactants. Anionic surfactants, mainly alkyl benzene sulfates, are used in detergents and cleaning agents.

Greasy soiling is generally removed by attaching surfactants to the soiling. The soils are surrounded by the surfactant molecules and form surfactant/soil micelles in an aqueous phase. The greasy dirt can thus dissolve in the form of a greasy/water emulsion and be carried away with the washing suds or the cleaning liquid.

It is normally not possible to predetermine the amount of detergent or cleaning agent required for an optimal cleaning process (hereinafter collectively referred to as treatment agent) because it depends on a number of parameters such as the type and degree of soiling, the load size or the material of the objects to be treated, for example the type of textile. As a rule, there is currently no precise determination of the amount actually required when using treatment agents in the household. Overestimating the degree of soiling or the load often results in overdosing. This increased consumption of treatment agents leads to an unnecessarily high environmental impact. Furthermore, after cleaning, undesired residues can remain on the objects in the event of an overdose and trigger allergies in people who come into contact with them.

It also happens that a user mistakenly mixes sensitive and non-sensitive textile types or is not aware of the correct care of the textiles. There is therefore a need to be able to observe and intervene in the course of a treatment process in a water-bearing household appliance.

In addition, odors can occur in water-bearing household appliances due to contamination with microorganisms or organic contamination. Other negative consequences are a deterioration in hygienic conditions. Such contamination often occurs in places on the household appliance that are difficult to access or not directly visible to a user. Identifying these hygienic impairments quickly and easily in order to initiate appropriate countermeasures is therefore an urgent need.

On the other hand, water-using household appliances that use volatile chemicals, such as propane, pose a relatively high safety risk and early detection of malfunctions or leaks is desirable in these cases.

Water-bearing household appliances with improved controls are already known.

The publication DE 10 2012 017 323 A1 describes a water-bearing household appliance, in particular a laundry treatment appliance for washing laundry, with a treatment area, a dosing pump, at least one Treatment agent container and a display device, wherein the treatment agent container serves to receive a quantity of a flowable treatment agent which is sufficient for several treatments in the treatment area. The amount of treatment agent delivered by the metering pump is displayed by the display device and/or a residual amount of treatment agent in the treatment agent container is displayed by the display device.

The publication DE 10 2010 039 611 A1 describes a dishwasher, in particular a household dishwasher, with a control device in which at least one wash program for executing a wash cycle comprising several partial wash cycles for cleaning and/or drying items to be washed is stored, and with an operating device for entering operating commands for the control device. At least one operating command for carrying out one or more adaptation measures to at least one of the washing programs can be entered on the operating device, by means of which the avoidance of stains on the items to be washed and/or the drying result on the items to be washed is improved when the wash cycle is carried out on the basis of the adapted washing program .

The use of radiation sensors, e.g. IR sensors, to detect the type of textile, the fill level and the amount of water in the drum of washing machines and tumble dryers is known.

The publication WO 2001/046509 A1 or. EP 1242665 B1 describes a device for treating textiles with a device for detecting properties of a textile, in particular a device with an evaluation circuit for detecting the type of textile and/or the moisture content of an item of laundry, the device having at least one transmitting element and at least one receiving element for transmitting or Receiving electromagnetic radiation and an evaluation circuit connected to the receiving element, wherein the radiation sent by the transmitting element and reflected and/or transmitted by the textile can be received by the receiving element and evaluated in the evaluation circuit. A method for detecting properties of a piece of textile, for example in a washing machine or in a tumble dryer, is also described.

The publication DE 10 2015 100 395 A1 describes a spectrometer, in particular for installation in a sensor module with a radiation source and the following components that define a beam path or are arranged along the beam path: a sample chamber for a fluid to be examined, a first lens, a diffraction element, a second lens, and a detector . A restriction aperture is provided between the sample space and the diffraction element to restrict the effective diameter of the beam impinging on the diffraction element.

The publication EP 0 816 551 B1 discloses infrared temperature sensing for a tumble dryer controller, particularly a dryer having a rotary drum for receiving and spinning moist articles to be dried, a heater for heating the articles, a blower unit for passing air over the articles in the drum, and an infrared sensing device that provides a control signal corresponding to the temperature of the articles in the drum. Also disclosed is a method of detecting the completion of a drying cycle in a dryer having a rotating drum and an infrared sensing device that provides a measurement of the temperature of the articles.

The publication JP H06 126099 A describes a method for operating a water-bearing household appliance with a drum for receiving objects to be treated, the drum having at least one perimeter with at least one radiation passage and the household appliance comprising a control device and an infrared sensor with a radiation detector. The infrared sensor detects the infrared radiation emitted by the objects to be treated through the radiation passage and determines the temperature of the objects to be treated as a function of the detected radiation.

That U.S. Patent No. 5,396,715 describes a microwave clothes dryer and a method with fire protection in which an IR sensor registers the temperature inside the drum and upon reaching a predetermined value indicative of burning clothes, the operation of the dryer is interrupted.

Proceeding from this state of the art, it was the object of the present invention to provide a method that enables improved control of a water-bearing household appliance with a spectrometer, with an improvement in the signal quality of a spectroscopic sensor preferably being enabled. Preferably, a more environmentally friendly and safer operation of the Household appliance are made possible. In addition, a household appliance suitable for carrying out this method is to be made available.

This object is achieved according to this invention by a method for operating a water-bearing household appliance and a household appliance suitable for carrying it out with the features of the corresponding independent patent claims. Preferred embodiments of the method according to the invention and of the household appliance according to the invention are set out in the respective dependent patent claims. Preferred embodiments of the method according to the invention correspond to preferred embodiments of the household appliance according to the invention and vice versa, even if this is not explicitly stated here.

1. (a) Rotieren der Trommel mit einer vorgegebenen Drehzahl Dz, wobei eine Frequenz f, bezogen auf die Anzahl von Umlaufzyklen von Strahlungsdurchlässen pro Zeiteinheit, als das Produkt der Drehzahl Dz mit der Anzahl von Strahlungsdurchlässen definiert wird;
2. (b) kontinuierliches Emittieren von Strahlung von der mindestens einen Strahlungsquelle des Spektrometers in einem Wellenlängenbereich λ₁ bis λ₂ durch den mindestens einen Strahlungsdurchlass der rotierenden Trommel, so dass eine mit der Frequenz f periodisch unterbrochene Strahlung innerhalb der Trommel erzeugt wird, und die Gegenstände in der rotierenden Trommel mit der Frequenz f periodisch unterbrochenen Strahlung beaufschlagt werden, und der mindestens eine Strahlungsdetektor derart angeordnet ist, dass die von den Gegenständen reflektierte Strahlung ohne den Strahlungsdurchlass zu passieren und somit ohne durch den Strahlungsdurchlass mit der Frequenz f unterbrochen zu werden, direkt als ein Messsignal registriert wird, und von der Steuereinrichtung eine nur vom Haushaltsgerät abhängige periodische Funktion mit der Periodenlänge 1/f, insbesondere eine Sinus- oder Rechteckfunktion, als Referenzsignal erzeugt wird, wobei das Referenzsignal im Wesentlichen von der Anzahl der Strahlungsdurchlässe, deren Geometrie, d.h. deren Größe und Form, und der Rotationsgeschwindigkeit der Trommel bestimmt ist;
3. (c) Übermitteln des Messsignals sowie des Referenzsignals an den Mikrocomputer, Auswerten des Messsignals und dessen Abgleich mit dem Referenzsignal mit einer im Mikrocomputer hinterlegten Auswerteroutine und Übermitteln des ausgewerteten Messsignals an die Steuereinrichtung; und
4. (d) Auswählen und/oder Anpassen eines Betriebsprogramms durch die Steuereinrichtung in Bezug auf das ausgewertete Messsignal, wobei die Schritte (b) bis (d) einmal oder mehrmals durchgeführt werden.

The subject matter of the invention is therefore a method for operating a water-bearing household appliance with a drum for receiving objects to be treated, which has at least one perimeter with at least one radiation passage, a control device, a spectrometer, which includes at least one radiation source, at least one radiation detector and a microcomputer , wherein the microcomputer and the control device are set up to exchange information with one another, so that data can be exchanged between the spectrometer and the control device, comprising the following steps:

1. (a) rotating the drum at a predetermined speed Dz, wherein a frequency f, related to the number of revolution cycles of radiant passages per unit time, is defined as the product of the speed Dz by the number of radiant passages;
2. (b) continuously emitting radiation from the at least one radiation source of the spectrometer in a wavelength range λ ₁ to λ ₂ through the at least one radiation passage of the rotating drum, so that a periodically interrupted radiation with the frequency f is generated inside the drum, and the objects in the rotating drum with the frequency f periodically interrupted radiation are applied, and the at least one radiation detector is arranged such that the radiation reflected from the objects without passing through the radiation passage and thus without being interrupted by the radiation passage with the frequency f, directly is registered as a measurement signal, and by the control device only from the household appliance dependent periodic function with the period length 1/f, in particular a sine or square-wave function, is generated as a reference signal, the reference signal being essentially determined by the number of radiation passages, their geometry, ie their size and shape, and the rotational speed of the drum;
3. (c) transmission of the measurement signal and the reference signal to the microcomputer, evaluation of the measurement signal and its comparison with the reference signal using an evaluation routine stored in the microcomputer and transmission of the evaluated measurement signal to the control device; and
4. (d) Selection and/or adjustment of an operating program by the control device in relation to the evaluated measurement signal, steps (b) to (d) being carried out once or several times.

The method according to the invention offers a number of advantages. Inexpensive, spectrally broadband illuminants, such as incandescent filaments, can be used as radiation sources. By using amplitude modulation, i.e. the periodic interruption of the illuminating light beam and the subsequent phase-sensitive signal rectification, the unfavorable signal-to-noise ratio that is generally obtained with conventional illuminants can be significantly reduced, which significantly increases the sensitivity of the measurements and even the smallest amounts of substances in the trace range can be detected. Furthermore, due to the possible efficient noise suppression, the more expensive narrow-band light sources required in the infrared range, such as switchable phosphorized LEDs, can be dispensed with. Furthermore, in the present invention, the rotating drum, with its typically defined radiation passages, can be used as a simple mechanical instrument for "chopping", i.e. periodically interrupting, the emitted radiation. A so-called "chopper wheel" which is usually used for this purpose and which is mechanically susceptible can be omitted, so that in this way the costs are further reduced and the reliability and accuracy of the spectroscopic measurements are also increased.

The terms "radiation transmission" or "radiation-transmissive" used herein are to be interpreted broadly. "Transmissive to radiation" within the meaning of the invention can mean the transparency to radiation in the entire spectral wavelength range or also refer to, for example, one or more defined wavelength ranges of the spectrum, such as infrared or UV radiation.

Furthermore, the design of the at least one radiation passage is not restricted according to the invention. This can be a material recess in the drum, i.e. a hole, or also, for example, an inlay made of a radiation-transmissive, i.e. transparent material, e.g. made of quartz glass or a plastic. According to the invention, the radiation passage is arranged on the front side, rear side or lateral surface of the drum.

In addition, the shape of the radiation passage is not restricted according to the invention. It can be, for example, a circular hole or an elliptical or rectangular recess. In addition, the size of the radiation passage is essentially only limited by the size that is sensible or permissible for a corresponding operation. In particular, the at least one radiation passage serves according to the invention to allow the radiation from a radiation source to enter the interior of the drum.

According to the invention, the drum rotates while the method is being carried out, with the at least one radiation passage passing through a position with a specific frequency f, depending on the speed Dz of the drum, which in step (b) of the method according to the invention enables the radiation to enter the interior of the drum . The same applies to reversing the drum. This position is referred to below as the corresponding position. In the case of several radiation passages, the frequency f results from the product of the speed Dz and the number of radiation passages.

In step (b) of the method according to the invention, it is provided that radiation from the at least one radiation source is emitted continuously in a wavelength range from λ ₁ to λ ₂ .

In this context, the term “continuously” means that the at least one radiation source of the spectrometer emits radiation without interruption while the method according to the invention is being carried out. What is achieved in this way is that when the drum rotates at frequency f, radiation is radiated into the interior of the drum when the at least one radiation passage is in the corresponding position.

According to the invention, there is no restriction as to whether, in step (b), the radiation is also emitted in the entire wavelength range from λ ₁ to λ ₂ and/or at a plurality of individual wavelengths and/or partial ranges within this wavelength range.

According to the invention, the radiation source generates radiation that is periodically interrupted with the frequency f inside the drum and impinges objects located therein with this radiation in at least one time period Δt. The length of the period Δt is not restricted in the method according to the invention, although it will depend on various parameters.

In particular, the length of the period Δt depends on the rotation speed of the drum. If the drum rotates at a speed Dz, so that the at least one radiation passage with a frequency f passes through the position which enables the radiation to enter the drum in step (b) of the method according to the invention, the length of the time period Δt depends on this frequency f . The length of Δt decreases with increasing speed Dz, i.e. higher frequency f.

In addition, the length of the time period Δt will increase with an increasing size of the at least one radiation passage. If the dimensions of the radiation passage are increased at a constant speed Dz, then Δt will increase since the objects inside the drum ("drum interior") are covered with radiation over a longer period of time.

The length of the at least one time period Δt is preferably in the range from 1 ms to 100 ms. The time interval Δt is particularly preferably in a range from 1 ms to 10 ms.

In addition to generating the radiation, which is periodically structured with the frequency f and which is applied to the objects inside the drum, a reference signal with the same frequency is also generated in parallel and sent to the microcomputer. The reference signal is a periodic function with the period length 1/f, a sine, cosine or square-wave function being preferred. The reference signal is one Periodic function with period length 1/f that is only dependent on the household appliance. The reference signal is essentially determined by the number of radiation passages, their geometry, ie their size and shape, and the rotational speed of the drum.

The radiation detector registers the radiation reflected from objects in the drum as a measurement signal over a steady, continuous period of time. This means that the reflected radiation from the objects impinges directly and immediately on the radiation detector without passing through the radiation passage again through which the periodically structured radiation was originally generated. Thus, in general, two different radiation paths can be distinguished. On the one hand the radiation path, which leads from the radiation source through the radiation passage in the drum wall into the interior of the drum in order to impinge on the objects inside the drum with radiation, on the other hand the radiation path of the reflected radiation, which leads directly from the reflecting objects to the radiation detector.

Due to the relatively long period of time that the detector has available for registering the reflected radiation, technically inferior and inexpensive radiation detectors can also be used, with high sensitivity and measurement accuracy still being achieved.

In addition to registering the radiation reflected from objects in the drum and thus determining their properties, it is generally also possible with the invention to measure properties of other fluid media, such as detergent or a gas phase in the water-bearing household appliance. Since part of the emitted radiation is reflected by the inner wall of the drum, this reflected radiation can be evaluated with regard to the components of the aqueous liquid or the gas phase.

With the method according to the invention, objects in the drum can be measured before, during and/or after treatment in the water-bearing household appliance. Within the meaning of the invention, measuring means impinging on Radiation from the at least one radiation source of the spectrometer and the registration of the measurement signal by the at least one radiation detector.

Items before treatment include items that have not yet undergone any treatment in the water-bearing household appliance. Thus, items to be treated are items that have one or more types of soiling or that require refreshment. Generally, items to be treated will be at least partially dry items. In the case of liquid soiling as a result of spilling drinks, there may also be residual moisture.

Objects during and/or after a treatment include all objects which are and/or have been subjected to at least one treatment in the household appliance. The term treatment is to be understood in a broad sense. According to the invention, a treatment is carried out in a controlled manner by the control device, including moistening with a defined amount of water W _F and carrying out a treatment program in part or in full. According to the invention, the type of objects is not restricted. The objects are preferably items of laundry.

Within the meaning of the invention, treatment programs are part of operating programs that can be carried out in a water-bearing household appliance. In this case, a treatment program can be a treatment program implemented at the factory in a water-conducting household appliance, one or more additional options or a user-defined treatment program. Thus, the concept of treatment program is to be interpreted broadly. Depending on the type and design of the water-bearing household appliance, a different number of treatment programs can be stored in the control device. In particular, a high-quality household appliance will have a larger number of treatment programs than an inexpensive one.

It is particularly advantageous if data on a wavelength-dependent reflection behavior of at least one type of textile, expediently of several types of textile, of the objects present in the drum are stored in the control device and/or in an external server, so that these can be used for measuring in Step b) and the evaluation and comparison in step c) of the method according to the invention can be used.

Polyester, linen, silk, cotton, acrylic or blended fabrics should be mentioned in particular as possible textile types. It is also possible with the method according to the invention to identify and allocate individual items of laundry present in the drum on the basis of the measurement signal(s) used.

It is expedient if the corresponding data on the wavelength-dependent reflection behavior is stored in such a way that the individual wavelengths and/or partial ranges within the wavelength range from λ ₁ to λ ₂ contain at least one wavelength in which no radiation is reflected. In particular, it is advantageous if the plurality of individual wavelengths and/or partial ranges within the wavelength range from λ ₁ to λ ₂ contain at least five wavelengths or wavelength ranges.

The method according to the invention has the significant advantage that the incidence of radiation via the openings in the rotating drum generally causes an amplitude modulation of the radiation impinging on the objects located in the drum. This amplitude modulation, which is available in functional form as a reference signal, is used to match the measurement signal to the reference signal with the aid of an evaluation routine executed in a microcomputer. As a result, the signal quality of the measurement signal can be significantly improved and interfering influences such as ambient light or scattered radiation can be eliminated. In this way it is generally possible to improve the signal-to-noise ratio by a factor of around 2 to 100.

A further advantage is that with the method according to the invention, inexpensive and spectrally broadband light sources, such as conventional light bulbs, can be used instead of expensive, switchable, phosphorized LEDs. Furthermore, the mechanically sensitive chopper wheel that is generally required for such an amplitude modulation and is usually used in combination with a broadband glow-wire source can be omitted.

In a particularly preferred embodiment of the method according to the invention, the microcomputer is designed as a lock-in amplifier or contains one.

With a lock-in amplifier, which acts as a phase-sensitive rectifier, the measurement signal can be compared with the reference signal and interfering noise effects can be filtered in a particularly efficient and optimized manner. In general, a lock-in amplifier contains the following elements: a signal input for the amplitude-modulated measurement signal, a signal input for the reference signal, a phase shifter for the adjustment between the measurement signal and the reference signal, a mixer that multiplies the measurement signal with the reference signal, and a low-pass filter, to perform a time averaging over several signal periods.

The lock-in amplifier calculates a cross-correlation between the measurement signal and the reference signal for a fixed phase shift by multiplying the measurement signal with the reference signal and subsequent integration in the low-pass filter. The cross-correlation for signals of different frequencies is zero. If the frequency of the measurement signal differs from that of the reference signal, the lock-in amplifier does not supply an output signal. The cross-correlation supplies a value not equal to zero and thus a contribution in the output signal of the lock-in amplifier only for identical frequencies. The corresponding component in the measurement signal can therefore be filtered out by selecting the frequency of the reference signal. The other frequencies, in particular high-frequency noise, mains hum or other interference signals, are filtered out by the low-pass filter. The frequency of the reference signal results from the speed of the drum and the number of radiation passages on the drum wall. The higher the frequency selected, the better the noise reduction achieved for the measured signal. The maximum frequency to be used must be selected taking into account the mechanical load capacity of the drum and the energy required. In particular, it is expedient to set the frequency using a spectrometer connected to the lock-in amplifier.

It is expedient if the wavelength range from λ ₁ to λ ₂ includes at least one absorption band of at least one type of textile and/or at least one absorption band of at least one typical contaminant. In addition, it is advantageous if in the control device and/or on an external server corresponding data on a wavelength-dependent reflection behavior of at least one type of textile at at least two moisture levels are available, so that these values can be used for the measurement in step b) and the evaluation in step c) of the method according to the invention.

In the event that the water-bearing domestic appliance is a washer-dryer, the drying process can be controlled quite precisely in this way in relation to a desired degree of residual moisture. In addition, it is possible to determine the degree of moisture before the start of the drying process in order to precisely adjust the corresponding drying program with regard to the type of fabric and degree of moisture.

Furthermore, it is advantageous to provide data on a wavelength-dependent reflection behavior of at least one treatment agent for the objects present in the drum in the control device and/or on an external server in order to use this data for the measurement in step (b) and the evaluation in step (c ) to use the method according to the invention.

The wavelength range from λ ₁ to λ ₂ particularly preferably includes at least two absorption bands of a treatment agent. In this way, a more precise determination of the content of treatment agent is made possible.

According to the present invention, the term "treating agent" is to be interpreted broadly. In particular, it includes any solid and/or liquid preparation that is suitable for bringing about a treatment result on objects to be treated in a water-bearing household appliance. Treatment agents thus include, in particular, cleaning or washing agents. As a rule, the proportion of surfactants, especially anionic surfactants such as alkyl benzene sulfates, in such preparations is relatively high, generally more than 80%. This allows the amount of treatment agent to be determined via the surfactant concentration.

The respective treating agents differ in their respective spectra, particularly absorption spectra, due to the intramolecular vibrations. The treatment agent used therefore generates a characteristic spectrum measured signals. It is preferred here if the reflection and absorption properties for at least one or preferably several treatment agents are stored in the control device and/or on an external database in order to be able to use these properties for the measurement in step (b) and the evaluation in step (c). to use.

In order to simplify the implementation of the method according to the invention, it is also possible, with regard to the invention, to limit oneself to typical treatment agents, in particular detergents, and to use them as a reference for the amount of treatment agent.

In particular, linear alkylbenzene sulfonates (LAS), which have a sulfone group bonded to the benzene ring, are widely used as surfactants. The wavelength range from λ ₁ to λ ₂ therefore preferably contains oscillation bands which are in the range of 1100 nm, 1400 nm, 1700 nm, 1900 nm, 2100 nm or in the range of 2300 to 2500 nm, particularly preferably two oscillation bands. This enables a reliable quantitative detection of these surfactants in particular.

It is also advantageous if data on a wavelength-dependent reflection behavior for at least one, preferably several standard contaminations are stored in the control device and/or on an external server, which are required for the measurement in step (b) and the evaluation in step (c) of the procedure can be used.

Within the meaning of the invention, these so-called standard soils are soils whose properties cover the entire range of possible soils on the objects to be treated. These include in particular fats or oils from leftovers, natural colorings, for example from tomatoes, carrots, red cabbage, red wine, blood, grass, proteinaceous impurities such as egg yolk and the like.

It is also particularly expedient if data on a wavelength-dependent reflection behavior for at least one, preferably several toxins and/or allergens are stored in the control device and/or on an external server Notifying the user of the presence of these substances, for example via a connected display device, and in step (d) of the method according to the invention the control device can adapt the treatment program accordingly, for example by including a further rinsing step in a washing machine.

Furthermore, it is advantageous to allow the user to use an operating unit to select the allergens or toxins to be detected in order to adapt the method according to the invention accordingly to his requirements.

In addition, it is advantageous if data on a wavelength-dependent reflection behavior for at least one, preferably several, volatile substances are stored in the control device and/or on an external server in order to be able to use these compounds for the measurement in step (b) and the evaluation in step ( c) to use the method according to the invention.

These volatile substances include, in particular, odor-causing compounds that are released by organic contaminants or microorganisms. For this purpose, in step (d) of the method according to the invention, a self-cleaning program can be selected by the control device and suitably adapted in order to remove these contaminants and to inform the user of his lack of hygiene.

In addition, the volatile substances can be gases, such as propane gas, which is used in heat pump clothes dryers. In step (d) of the method according to the invention, it is expedient in this case to interrupt the running program if necessary and to warn the user. This warning can be announced optically via a display device, in words and/or images and/or with the help of light signals, as well as a warning tone.

A corresponding security warning can also be communicated to the user via modern communication media as an app or an SMS if the household appliance according to the invention is connected to a wireless network. In addition, security services such as the fire brigade can be notified.

In step (d) of the method according to the invention, it is provided that the control device uses the measurement signal evaluated and transmitted in step (c) to select and/or adapt an operating program for the objects present in the drum in relation to the evaluated measurement signal.

In contrast to the aforementioned term "treatment program", the term "operating program" is to be understood in a broader sense. Operating programs include both treatment programs and program sequences that are implemented in addition to the treatment programs in the water-bearing household appliance. An operating program can therefore also be a self-cleaning program. The term “operating program” also includes the output of information to a user, for example via a display device, and the transmission of information, for example by means of a wireless data connection. Consequently, operating programs contain all of the operations to be carried out by the control device in a household appliance according to the invention.

If the water-bearing household appliance according to the invention is a washing machine, for example, and the user accidentally put a colored item of laundry in the drum together with only white items of laundry to be washed and has selected and already started the relevant treatment program for pure white laundry, the control device can in this case Adjust the treatment program with regard to the treatment of the colored laundry in order to prevent undesired staining on the pure white laundry. Corresponding damage avoidance can be achieved by adjusting the speed and/or rotation rhythm and/or temperature.

Furthermore, it is possible for the control unit to indicate to the user before the start that there is colored laundry and to propose a respective program for colored laundry. The user also has the option of removing the colored item of laundry from the drum.

There is also the option of placing a selected individual item of laundry in the drum if the care label is missing to determine the type of textile. In this In this case, the control device can also suggest the appropriate treatment program.

In step (c), the microcomputer generates at least one spectrum from the spectral measurement signals, optionally with the additional involvement of the lock-in amplifier, with the number of spectra generated not being limited according to the invention.

It is also advantageous if a calibration measurement is carried out with a rotating drum in a defined loading condition between steps (a) and (b) of the method according to the invention, in particular before the start of a treatment program. The term "loading condition" is to be understood broadly in this context, in that it also includes the moisture content of the objects, in particular items of laundry, in addition to a dry load quantity.

For the quantitative evaluation of a spectrum, the spectrum is usually normalized to a standard. This enables a recorded spectrum to be compared with a calibration spectrum. In addition, several recorded spectra can be compared with each other, for example to track the change in concentration of a specific substance.

If the wavelength range from λ ₁ to λ ₂ is in the infrared, Spectralon is preferably used as the standard.

It is particularly expedient if, before the method according to the invention is carried out, a baseline is recorded and a corresponding baseline correction is carried out. A more precise analysis is achieved by subtracting the baseline from the measured values, since contamination present in the area of the detector or emitter in particular can be taken into account. In addition, a general functional check of the spectrometer is carried out in this way. If the measurement of the baseline shows that the optics of the detector and/or emitter are heavily contaminated, an automatic cleaning program can be carried out and then the measurement of the baseline can be restarted.

In order to obtain an image of a plurality of objects in the drum that is as comprehensive and complete as possible, it is particularly advantageous in the case of a high load if the drum reverses briefly after each process run. This rotation reversal improves the mixing of the laundry items in the drum and optimizes the measurement results. The method is expediently repeated several times, in particular until there is no longer any noticeable change in the measured values.

In the case of a washing machine or a washer-dryer, suitably designed laundry drivers can be provided in the drum as a water-bearing domestic appliance in order to improve the mixing of the laundry items.

There are a number of evaluation routines for the qualitative and quantitative evaluation of the spectra that depend on the measurement signals received. The evaluation routines used are therefore not subject to any restrictions according to the invention. The evaluation is preferably carried out in good approximation on the basis of the Lambert-Beer law with the aid of a multivariate data analysis. A principal components analysis with a non-linear iterative partial least squares algorithm with subsequent partial least squares regression is suitable for this, for example, from which a response matrix can be obtained.

In a preferred embodiment, the control device is designed to store evaluated measurement signals. In this way, the control device can collect empirical values with which the operation of the water-bearing domestic appliance can be continuously optimized. Individual requirements of the user can therefore be taken into account and an environmentally friendly operation of the household appliance can be implemented.

The speed Dz of the drum in the process according to the invention is preferably 20 to 200 rpm. In this speed range there is a sufficiently high amplitude modulation of the radiation impinging on the objects located in the drum via radiation passages in order to achieve a significant improvement in the signal-to-noise ratio of the measured values obtained. Also can these speeds can be achieved with conventional motors and drive units without disproportionately high energy expenditure. Since the speed of the drum also determines the length of time of a light packet entering through the radiation passage and the time between successive packets, the absorption behavior of the substances to be detected, in particular their residence times in the excited states, also plays an important role in the selection of a suitable speed.

In a further preferred embodiment of the method according to the invention, the method additionally comprises a step (e), namely the cleaning of the spectrometer.

The type of cleaning of the optics of the spectrometer is not restricted according to the invention. If the household appliance according to the invention is a washing machine or a washer-dryer, cleaning can be carried out using an aqueous liquid in a treatment program. In addition, it is possible to rinse the spectrometer optics separately via a line with rinsing liquid. It is also possible to provide a sponge or a correspondingly suitable material at a selected point on the outside of the drum, with the spectrometer optics being cleaned by the sponge stroking over it as the drum rotates. It is also possible, by means of a suitable mechanical device which is connected to the door opening system, to actuate a cleaning unit when the door of the household appliance according to the invention is opened, which moves in front of the spectrometer and cleans its optics. Analogously, a calibration device could also be activated by opening and closing the device door, which performs a calibration and/or a baseline correction of the spectrometer.

1. (a) Rotieren der Trommel mit einer vorgegebenen Drehzahl Dz, wobei eine Frequenz f, bezogen auf die Anzahl von Umlaufzyklen von Strahlungsdurchlässen pro Zeiteinheit, als das Produkt der Drehzahl Dz mit der Anzahl von Strahlungsdurchlässen definiert wird;
2. (b) kontinuierliches Emittieren von Strahlung von der mindestens einen Strahlungsquelle des Spektrometers in einem Wellenlängenbereich λ₁ bis λ₂ durch den mindestens einen Strahlungsdurchlass der rotierenden Trommel, so dass eine mit der Frequenz f periodisch unterbrochene Strahlung im Inneren der Trommel erzeugt wird, und Gegenstände in der rotierenden Trommel mit der Frequenz f periodisch unterbrochenen Strahlung beaufschlagt werden, und der mindestens eine Strahlungsdetektor derart angeordnet ist, dass die von den Gegenständen reflektierte Strahlung ohne den Strahlungsdurchlass zu passieren und somit ohne durch den Strahlungsdurchlass mit der Frequenz f unterbrochen zu werden, direkt als ein Messsignal registriert wird, und von der Steuereinrichtung eine nur vom Haushaltsgerät abhängige periodische Funktion mit der Periodenlänge 1/f, insbesondere eine Sinus- oder Rechteckfunktion, als Referenzsignal erzeugt wird;
3. (c) Übermitteln des Messsignals sowie des Referenzsignals an den Mikrocomputer, Auswerten des Messsignals und dessen Abgleich mit dem Referenzsignal mit einer im Mikrocomputer hinterlegten Auswerteroutine und Übermitteln des ausgewerteten Messsignals an die Steuereinrichtung; und
4. (d) Auswählen und/oder Anpassen eines Betriebsprogramms durch die Steuereinrichtung in Bezug auf das ausgewertete Messsignal;

wobei die Schritte (b) bis (d) einmal oder mehrmals durchgeführt werden.In addition, the subject of the invention is a water-bearing household appliance with a drum for receiving objects to be treated, which has at least one perimeter with at least one radiation passage, a control device, a spectrometer, which includes at least one radiation source, at least one radiation detector and a microcomputer, the microcomputer and control device are set up to exchange information with each other, so that data between the spectrometer and control device can be exchanged, the control device being set up to carry out a method which comprises the following steps:

1. (a) rotating the drum at a predetermined speed Dz, wherein a frequency f, related to the number of revolution cycles of radiant passages per unit time, is defined as the product of the speed Dz by the number of radiant passages;
2. (b) continuously emitting radiation from the at least one radiation source of the spectrometer in a wavelength range λ ₁ to λ ₂ through the at least one radiation passage of the rotating drum, so that a periodically interrupted radiation with the frequency f is generated inside the drum, and objects in the rotating drum with the frequency f periodically interrupted radiation are applied, and the at least one radiation detector is arranged such that the radiation reflected from the objects without passing through the radiation passage and thus without being interrupted by the radiation passage with the frequency f, directly is registered as a measurement signal, and a periodic function which is dependent only on the household appliance and has a period length of 1/f, in particular a sine or square-wave function, is generated as a reference signal by the control device;
3. (c) Transmission of the measurement signal and the reference signal to the microcomputer, evaluation of the measurement signal and its comparison with the reference signal using an evaluation routine stored in the microcomputer and transmission of the evaluated measurement signal to the control device; and
4. (d) selection and/or adjustment of an operating program by the control device in relation to the evaluated measurement signal;

wherein steps (b) to (d) are performed one or more times.

According to the invention, the water-bearing domestic appliance is generally selected from the group comprising a washing machine, a washer-dryer and a tumble dryer. The water-bearing domestic appliance is preferably a washing machine or a washer-dryer. The water-bearing household appliance is particularly preferably a washing machine.

As a rule, the household appliance according to the invention has a treatment agent container and preferably also a dosing unit. The form and type of design of the dosing unit is not restricted according to the invention. Especially it can be a dosing unit for manual dosing of treatment agent or an automated dosing unit.

In a preferred embodiment, the water-bearing domestic appliance according to the invention has a treatment agent container and an automated metering unit for metering treatment agent, which is connected to the control device.

In a particularly preferred embodiment of the water-bearing household appliance according to the invention, the dosing unit is an automated dosing unit that is connected to the control device and can be controlled by it in order to dose the treatment agent, such as when the dosing quantity falls below an optimal level. The automated dosing system can preferably be combined with a modular system for the treatment agent in order to be able to provide the optimum dose and composition of treatment agent for the respective specific requirements in terms of type and degree of soiling, textile types and load.

It is also advantageous if the drum of the household appliance according to the invention has a predetermined start/stop position. The manner in which such a start/stop position of the drum is implemented in the water-bearing household appliance is not restricted according to the invention. Possible configurations are, for example, a mechanical design or storage of a selected drum position in the control device, which is activated before the method according to the invention is carried out.

In the water-bearing household appliance, the arrangement of the spectrometer is only restricted according to the invention to the extent that the emission of radiation in a wavelength range λ ₁ to λ ₂ through the at least one radiation passage and the detection of the radiation reflected by objects arranged in the drum is possible directly and unhindered, without the radiation having to pass through the at least one radiation aperture again in order to be interrupted. The arrangement can vary depending on the embodiment of the household appliance and are based in particular on the type and structure of the water-bearing household appliance.

In a preferred embodiment, the water-bearing domestic appliance is a washing machine or a washer-dryer with a tub and a drum for holding items of laundry. The spectrometer is then preferably arranged in a recess in the tub shell.

It is advantageous if the spectrometer can be pivoted and the alignment of the spectrometer can be controlled by the control device in such a way that, in particular, a plurality of perimeters of the drum, usually spaced apart perpendicularly to the perimeter, each preferably having a plurality of radiation passages, in particular holes , can be detected. In this case, holes are, in particular, those radiation passages which are characterized by the absence of a solid, radiation-transmissive material.

In a preferred embodiment of the household appliance, the at least one radiation passage is therefore a hole.

In an alternative embodiment of the household appliance, the at least one radiation passage is made of glass or transparent plastic. In a further preferred embodiment of the water-conducting household appliance according to the invention, the at least one radiation passage is a transparent plastic inlay or is made from quartz glass. According to the invention, the size and shape of the transparent plastic inlay or the quartz glass are not restricted. In particular, this can be an elongated ellipse or an elongated rectangle, with the respective longer side preferably extending in the perimeter direction. The plastic inlay can be designed as a plastic ring, for example. The plastic used for the inlay is preferably permeable to infrared radiation.

In the household appliance according to the invention, the at least one radiation passage is generally arranged on the front side, rear side or lateral surface of the drum.

According to the invention, the design of the at least one radiation passage is not restricted. It is particularly expedient if the at least one radiation passage of the water-conducting household appliance according to the invention has a circular shape. The diameter of the radiation passage, in particular a hole, along the outside of the drum, in particular along the lateral surface of the drum, is preferably 10 to 20 mm, with the diameter of the hole preferably tapering towards the inside of the drum. Excessively large diameters of the radiation passage when arranged on the drum shell should be avoided, as otherwise there is a risk that parts of laundry items will be pushed out of the passage openings, i.e. holes, and damaged by centrifugal forces during rotation of the drum. If, on the other hand, the passage openings are arranged on the front or rear side of the drum, larger openings are also possible without the risk of laundry items being pushed out or thrown out.

In another preferred embodiment of the water-conducting household appliance according to the invention, the at least one radiation passage has an elliptical shape.

The semimajor axis is preferably ≦10 mm long, in particular 2 to 5 mm, and the semimajor axis preferably has a length of ≦2 mm.

The drum may further include a plurality of holes along the at least one perimeter. In a preferred embodiment of the water-bearing household appliance according to the invention, the at least one perimeter is designed as a perforated ring. The drum preferably has a plurality of such perforated rings. The at least one perforated ring can be provided on the drum shell and on the front and/or rear of the drum.

In a particularly preferred embodiment of the water-bearing household appliance according to the invention, a bulge made of quartz glass or transparent plastic is arranged on the back of the drum instead of a ring of holes, the axis of symmetry of which lies in the axis of rotation of the drum. It is expedient if the recess has an axisymmetric shape, for example a teardrop or thorn shape. This bulge can have a more or less large recess in its interior.

In a preferred embodiment of the household appliance according to the invention, the at least one radiation passage is formed as an axially symmetrical, transparent bulge protruding from the rear of the drum into the interior of the drum, the axis of symmetry of the bulge lying on the axis of rotation of the drum, and the rear of the bulge facing away from the interior of the drum has a non-transparent layer, which has at least one radiation passage, in particular an opening, in a concentric arrangement to the axis of rotation of the drum, in order to allow radiation to fall through the radiation passage or the opening and the transparent bulge into the interior of the drum.

The "chopping" of the light beam emitted by the radiation source is produced here by the periodic incidence of radiation when this beam alternately hits the radiation-impermeable or reflective layer and the at least one transparent opening at the base of the recess. The emitted light beam is preferably formed by a laser beam which runs essentially parallel to the axis of rotation of the drum and is directed at a point on the concentric path of the at least one opening.

The bulge can thus be formed completely from the transparent material, so that the radiation entering through the opening propagates in the recess or the bulge and a diffuse incidence of radiation into the interior of the drum is brought about. In this way, the objects in the drum are evenly exposed to the radiation.

Alternatively, radiation guide channels, for example glass fibers, can be connected to the radiation passages or openings, which only guide the radiation within these radiation channels to a defined point on the surface of the recess, preferably at its tip, so that only from there does the radiation enter the inside the drum.

According to the invention, the arrangement of the at least one radiation source and the at least one radiation detector relative to one another is generally selected in such a way that the reflected radiation can be detected directly. It is expedient if the detector is arranged above the radiation source. Furthermore, an arrangement of the radiation source and detector is preferred which is as far down as possible, but above the maximum water level. It is essential that the detector has a clear field of view of the point illuminated by the radiation source. The focus or acceptance angle of the detector on the area to be examined is preferably adjusted and optimized by mirror and/or lens devices. The light emitted by the radiation source is also preferably focused by means of optical aids through the radiation inlet in order to illuminate a specific area inside the drum in a stroboscopic manner.

According to the invention, the radiation source is not restricted. In particular, radiation sources for the infrared (IR), ultraviolet (UV) or UV-VIS (ultraviolet and visible) range can be used.

The at least one radiation source can be a broadband source, in particular an incandescent filament preferably made of tungsten, a tunable radiation source or a narrow-band radiation source, such as an IR LED. Broadband radiation sources are advantageous for cost reasons, since the amplitude modulation technique used in the method according to the invention efficiently suppresses noise effects and achieves a good signal-to-noise ratio, so that expensive narrowband sources are not necessary. In addition, the radiation source can have optical aids, in particular focusing optics, filter plates, filter foils or filter coatings and a MOEMS Fabry-Perot frequency filter, which allow the wavelength range to be set. Several radiation sources, also of different designs, can be provided on the spectrometer.

In a particularly preferred embodiment of the water-conducting household appliance according to the invention, the at least one radiation source is a broadband source for emitting radiation in the infrared range.

The radiation source is particularly preferably used to emit radiation in the near-infrared range and is selected from the group comprising a tungsten-halogen lamp and a MOEMS black-body radiator.

Furthermore, the at least one radiation detector is not restricted. The radiation detector can be a broadband detector with at least one sensitive detector surface N, for example. In addition, the radiation detector can have a plurality of sensitive surfaces N or a linear arrangement of detector surfaces N, for example in the form of pixels. In addition, the detector can have optical tools such as a MOEMS Fabry-Perot frequency filter, narrow-band filters or a dispersive wedge. The material constituting the radiation detector is also not restricted according to the invention. The radiation detector preferably consists of at least one semiconducting material.

In an IR spectrometer, the radiation source can be a tungsten-halogen lamp with 5 filter plates for narrow-band excitation. In general, the radiation detector 5 has sensitive detector surfaces in order to detect the reflected radiation.

In addition, the radiation source in an IR spectrometer can contain narrow-band IR LEDs, 5 such LEDs with multiplexing preferably being provided. In this case, the radiation detector has N sensitive detector surfaces and consists at least partially of indium gallium arsenide.

A MOEMS blackbody radiator is also suitable as a radiation source for the spectrometer. In this case, the radiation detector consists of a sensitive detector surface N and has a MOEMS Fabry-Perot frequency filter. In this way, a narrowband frequency sweep through the wideband can be performed.

In addition, the radiation source can be a DFB laser and the radiation detector can have a sensitive detector surface N. In this case, the sensitive detector surface preferably consists at least partially of germanium, so that measurements can also be made as a function of time.

For a household with networked appliances, the water-bearing household appliance preferably also has an interface for wireless data transmission, with the control device and the microcomputer being set up for wireless information exchange with one another. In this case, the microcomputer can preferably be an external server or implemented on it. In this way, the water-bearing household appliance is also suitable for operation in a network and can be conveniently operated via an app using an external operating unit, such as a mobile phone and/or a tablet PC.

In this case, the water-bearing household appliance is particularly preferably integrated into a home network with at least one other household appliance. In this way, information for controlling operating programs can advantageously be transferred from one household appliance to another.

If the water-bearing domestic appliance is a washing machine, a determined residual moisture content of the washed items of laundry can be transmitted to a dryer in the home network and the drying program to be followed can be adjusted accordingly to the residual moisture content.

Household appliances usually have at least one display device that can be configured to output information as text, images and/or characters, in color and/or black and white, statically and/or animated. Warnings and/or other information can be communicated to a user via the display device. In a particularly preferred embodiment, the display device is an external display device, such as the touchscreen of a smartphone or a tablet PC.

The invention has numerous advantages. Up to now it has not been possible to measure objects in the drum of a water-bearing household appliance while the drum is rotating at a short distance with a spectrometer using amplitude modulation. This also allows the spectroscopic detection of substances that are only present in traces, since even small measurement signals can be registered due to the improved signal-to-noise ratio. The use of one for this The normally customary separate chopper wheel, which is prone to failure, is no longer necessary, since its function is fulfilled by the rotating drum. Furthermore, the invention enables a direct determination with only a small "sample to detector" distance. The current treatment program can thus be controlled individually and treatment agents can be saved by specifically adapting the amount of treatment agent in the dosing phase to the respective requirements and circumstances, ie to the degree of soiling of the laundry items and the load quantity. Experience has shown that the user tends to use excessive amounts, so that the treatment of objects in a water-bearing household appliance can be carried out in a more environmentally friendly manner with the invention.

In addition, the determination of textile types avoids damage to textiles in the event of incorrect loading by a user, for example if both colored and pure white items of laundry are to be washed accidentally. In addition, the safety for a user is increased since volatile compounds such as propane, which can be released when using a propane gas heat pump dryer, can be detected using the method according to the invention. Health risks, such as those caused by allergens or germs that cause other diseases, can be reduced by determining microbiologically relevant substances. A tailor-made implementation of washing and drying programs is made possible by determining the type and extent of soiling present and the moisture content after the washing process.

In Figur 1

ist eine nicht einschränkende Ausführungsform eines zur Durchführung des erfindungsgemäßen Verfahrens geeigneten wasserführenden Haushaltsgeräts in Form einer Waschmaschine, in der das Spektrometer im Laugenbehältermantel innerhalb einer Aussparung positioniert ist, gezeigt.

In Figur 2

ist in einer Ausführungsform eine schematische Darstellung des dem erfindungsgemäßen Verfahrens zugrundeliegenden Messprinzips gezeigt.

Further details of the invention emerge from the following description of non-limiting embodiments. Reference is made to the figures 1 and 2 .

In Figure 1

1 shows a non-limiting embodiment of a water-conducting domestic appliance suitable for carrying out the method according to the invention, in the form of a washing machine, in which the spectrometer is positioned in the tub shell within a recess.

In Figure 2

In one embodiment, a schematic representation of the measuring principle on which the method according to the invention is based is shown.

In figure 1 a water-carrying household appliance 1 designed as a washing machine and suitable for carrying out the method according to the invention is shown. The washing machine 1 has a housing 12 in which a tub 2 is arranged, a drum 3 for receiving items of laundry 22 being rotatably mounted therein about an axis perpendicular to the plane of the figure. The highest water level 25 that can be reached in the tub is shown schematically by a horizontal dashed line.

In the case of the embodiment shown here, a tub drain line 17 is connected to a drain opening 26 in a base of the tub 2 and leads to a suction side of a pump 14 via a lint separator 19 . In addition, a discharge line 13 is connected to a pressure side of the pump 14 . In this case, the pump 14 is drivingly connected to a speed-controlled drive motor 20 which can be designed, for example, as a permanently excited, multi-phase synchronous motor with a MOSFET component and a power detector 15 . Not shown here is the mouth of the drain line 13 outside the housing in a house sewage line or a floor drainage.

In addition, in figure 1 an automated dosing unit 8 for treatment agents is shown, which is connected to a dispensing bowl 11. Water can be supplied to the tub 2 via the flushing tray 11 from a fresh water line 10 . For this purpose, a check valve 9 is provided in the fresh water line 10, which is controlled by a control device 18 according to a treatment program sequence.

An IR spectrometer 21 is arranged in a recess 4, which is located in the shell of the tub 2. A broadband radiation source 5 is included in the IR spectrometer 21 which is capable of emitting IR radiation in the near infrared range and which in this non-limiting embodiment is embodied as a tungsten-halogen lamp. In this way, radiation in a continuous spectrum with a wavelength of 300 nm to 3 μm can be emitted by the IR spectrometer 21 .

In this embodiment, the absorption bands of polyester are to be excited in a broadband manner with the aid of the broadband IR source. In particular, polyester has characteristic absorption bands at the wavelengths 1180 nm, 1237 nm, 1266 nm, 1285 nm, 1322 nm, 1387 nm, 1410 nm, 1483 nm, 1514 nm, 1594 nm, 1661 nm, 1908 nm, 1953 nm, and 2083 nm 2136 nm. In these wavelength ranges, other types of textile also show corresponding typical absorption bands, which can also be excited in a broadband manner.

The absorption bands of sulfone groups are also in this range. In particular, the surfactant class of LAS (linear alkylbenzene sulfonates) contains the sulfone group, which shows two characteristic absorption bands, a first in the wavelength range from 1.03 µm to 1.17 µm and a second in the wavelength range from 1.14 µm to 1.37 µm. The measuring range from λ ₁ to λ ₂ extends from 0.90 µm to 1.70 µm. In parallel with the identification of textile types, the type and/or quantity of the treatment agent can thus also be determined in further embodiments.

In addition, it is possible in other embodiments to determine the degree of moisture from the superimposition of the water bands on the basis of the decreasing broadband intensity of the textile bands with increasing water content.

In addition, the IR spectrometer 21 includes, in front of the drum 3, a radiation detector 7 which, in this non-limiting embodiment, is an uncooled single-pixel indium gallium arsenide detector. In addition, a matrix detector, in particular a matrix sensor with a linear line array, can also be used. A MOEMS Fabry-Perot frequency filter (not shown) precedes the radiation detector 7 . In this way, the time-dependent broadband spectrum can be obtained in this embodiment by varying the spacing of the resonator plates.

Furthermore, in this embodiment it is provided that the drum 3 has a perforated ring 35 . The holes of the perforated ring 35 are arranged in a circle with a diameter of 2 mm on the outer wall 29 of the drum. The IR spectrometer 21 is arranged in such a way that IR radiation continuously emitted by the IR radiation source 5 enters the interior of the drum 3 through a respective hole in the ring of holes 35 in order to to cover the items of laundry 22 in the drum 3 with the emitted radiation. In the embodiment shown, the radiation detector 7 is arranged in front of the drum 3 and has a clear field of view of the area illuminated by the IR radiation source 5 . The radiation detector 7 can thus register the radiation reflected from this point in question directly and immediately as a measurement signal over a continuous period of time without the radiation path being interrupted by other objects, in particular the drum wall 29 . In this embodiment, the rotating speed of the drum 3 is 60 rpm with a direction of rotation indicated by the arrow 23 . The length of time Δt of a packet of emitted radiation, which penetrates through the radiation passage 30 into the interior of the drum 3, is 1 ms in this embodiment.

The microcomputer 6 receives the measurement signals registered by the radiation detector 7 as a sensor signal (reflection) as a function of time and the periodic reference signal defined by the speed of the drum 3 . The sensor signal is compared with the reference signal by multiplication and subsequent integration and converted into the broadband spectrum with an evaluation routine stored in the microcomputer 6 and evaluated. Spectrometer 21 and microcomputer 6 form a functional unit.

16 denotes an indicator; 24 means a laundry carrier.

In figure 2 a schematic representation of the measuring principle is shown, on which the method according to the invention is based. In particular, the measuring principle is based on a reflection measurement. A textile part 34 arranged in the drum 3 of a water-bearing domestic appliance is exposed to radiation from a radiation source S 27 . In this case, the radiation 31 is applied through a hole in the drum outer wall 29 as a radiation passage 30 with a diameter D _L , the direction of rotation of the drum 3 being indicated by the arrow 33 . It is advantageous if the hole 30 is irradiated through its center as far as possible. There is a diffuse back-reflection of radiation after the interaction with the laundry item 34, which is described by the Lambert-Beer law. The diffusely reflected back radiation 32 is detected by the radiation detector D 28 . In this embodiment, with a Dz of the drum 3, the period of time is Δt of an irradiated light packet D _L /U*Dz, where U denotes the circumference of the drum 3. The duration Δt of a radiation packet can therefore be changed by varying the speed Dz, the drum circumference U and the hole diameter D _L . In this way, the method according to the invention can be flexibly adapted to different types of spectrometers and water-bearing household appliances.

Reference sign

1

water-bearing household appliance; Washing machine

2

tub

3

drum

4

tub recess; Recess in the tub

5

broadband radiation source, IR radiation source

6

microcomputer

7

radiation detector

8th

(automated) dosing unit for treatment agents

9

check valve

10

fresh water line

11

dispenser bowl

12

Housing

13

drain line

14

pump

15

performance recorder

16

display device

17

tub drain line

18

control device

19

lint separator

20

speed-controlled drive motor

21

Spectrometer, IR spectrometer

22

laundry items

23

direction of movement of the drum

24

laundry carrier

25

water level

26

Drainage hole in the bottom of the tub

27

Radiation source, IR radiation source

28

radiation detector

29

drum (outer) wall

30

Radiation passage, hole in the drum shell (drum (outside) wall)

31

Emitted radiation, IR radiation

32

Detected reflected radiation

33

direction of movement of the drum

34

Item of laundry in the interior of the drum

35

perforated ring

Claims (15)

1. Method for operating a water-conducting household appliance (1) with a drum (3) for receiving items (22, 34) to be treated, which has at least one perimeter with at least a radiation passage (30, 35), a control facility (18), a spectrometer (21), which comprises at least one radiation source (5, 27), at least one radiation detector (7, 28) and a microcomputer (6), wherein microcomputer (6) and control facility (18) are designed to exchange information with one another so that data can be exchanged between spectrometer (21) and control facility (18), characterised in that it comprises the following steps:

   (a) rotating the drum (3) with a predetermined rotational speed Dz, wherein a frequency f, in respect of the number of rotation cycles of radiation passes (30, 35) per time unit, is defined as the product of the rotational speed Dz with the number of radiation passes (30, 35);

   (b) continuously emitting radiation (31) from the at least one radiation source (5, 27) of the spectrometer (21) in a wavelength range λ₁ tο λ₂ through the at least one radiation passage (30, 35) of the rotating drum (3), so that a radiation (31) interrupted periodically with the frequency f is produced within the drum (3), and the items (22, 34) in the rotating drum (3) are subjected periodically to interrupted radiation (31) with the frequency f and the at least one radiation detector (7, 28) is arranged such that the radiation (32) reflected by the items (22, 34) is registered directly as a measuring signal without passing through the radiation passage (30, 35) and without being interrupted by the frequency f through the radiation passage (30, 35) and a periodic function, with a period length 1/f, in particular a sinus or rectangular function, which is only dependent on the household appliance (1), is produced by the control facility (18) as a reference signal, wherein the reference signal is determined substantially by the number of radiation passages (30, 35), the geometry thereof, i.e. the size and shape thereof, and the rotational speed of the drum (3);

   (c) transmitting the measuring signal and the reference signal to the microcomputer (6), evaluating the measuring signal and its comparison with the reference signal with an evaluation routine stored in the microcomputer (6) and transmitting the evaluated measuring signal to the control facility (18); and

   (d) selecting and/or adjusting an operating program by means of the control facility (18) in relation to the evaluated measuring signal, wherein the steps (b) to (d) are carried out once or repeatedly.
2. Method according to one of the preceding claims, characterised in that the microcomputer (6) is embodied as a lock-in amplifier or contains one such.
3. Method according to one of the preceding claims, characterised in that the wavelength range λ₁tο λ₂ comprises at least one absorption band of at least one textile type and/or at least one absorption band of at least one typical contaminant.
4. Method according to one of the preceding claims, characterised in that between steps (a) and (b), in particular before the start of a treatment program, a calibration measurement with a rotating drum (3) is carried out in a defined loading state.
5. Method according to one of the preceding claims, characterised in that the rotational speed Dz amounts to 20 to 200 rpm.
6. Method according to one of the preceding claims, characterised in that it additionally comprises a step (e)
   (e) cleaning the spectrometer (21).
7. Water-conducting household appliance (1) with a drum (3) for receiving items (22, 34) to be treated, which has at least one perimeter with at least one radiation passage (30, 35), a control facility (18), a spectrometer (21), which comprises at least one radiation source (5, 27), at least one radiation detector (7, 28) and a microcomputer (6), wherein microcomputer (6) and control facility (18) are designed to exchange information with one another so that data can be exchanged between spectrometer (21) and control facility (18), characterised in that the control facility (18) is designed to carry out a method which comprises the following steps:

   (a) rotating the drum (3) with a predetermined rotational speed Dz, wherein a frequency f, in relation to the number of rotation cycles of radiation passages (30, 35) per time unit, is defined as the product of the rotational speed Dz with the number of radiation passages (30, 35);

   (b) continuously emitting radiation (31) from the at least one radiation source (5, 27) of the spectrometer (21) in a wavelength range λ₁ to λ₂ through the at least one radiation passage (30, 35) of the rotating drum (3), so that a radiation (31) interrupted periodically with the frequency f is produced within the drum (3), and the items (22, 34) in the rotating drum (3) are subjected periodically to interrupted radiation (31) with the frequency f and the at least one radiation detector (7, 28) is arranged such that the radiation (32) reflected by the items (22, 34) is to pass without the radiation passage (30, 35) and is thus to be interrupted without through the radiation passage (30, 35) with frequency f, is registered directly as a measuring signal and a periodic function, with a period length 1/f, in particular a sinus or rectangular function, which is only dependent on the household appliance (1), is produced by the control facility (18) as a reference signal, wherein the reference signal is determined substantially by the number of radiation passages (30, 35), the geometry thereof, i.e. the size and shape thereof, and the rotational speed of the drum (3);

   (c) transmitting the measuring signal and the reference signal to the microcomputer (6), evaluating the measuring signal and its comparison with the reference signal with an evaluation routine stored in the microcomputer (6) and transmitting the selected measuring signal to the control facility (18); and

   (d) selecting and/or adjusting an operating program by means of the control facility (18) in relation to the evaluated measuring signal, wherein the steps (b) to (d) are carried out once or repeatedly.
8. Household appliance (1) according to claim 7, characterised in that the household appliance (1) has a treatment agent container and an automated dosing unit (8) for dosing treatment agent, which is connected to the control facility (18).
9. Household appliance (1) according to claim 7 or 8, characterised in that the at least one radiation source (5, 27) is a broadband source for emitting radiation (31) in the infrared range, in particular a glow filament.
10. Household appliance (1) according to one of claims 7 to 9, characterised in that the household appliance (1) is a washing machine or a tumble dryer with a wash tub (2) and the radiation source (5, 27) is arranged in a cut-out (4) of the wash tub (2).
11. Household appliance (1) according to one of claims 7 to 10, characterised in that the drum (3) has a predetermined start/stop position.
12. Household appliance (1) according to one of claims 7 to 11, characterised in that the at least one radiation passage (30, 35) is a hole (30).
13. Household appliance (1) according to one of claims 7 to 11, characterised in that the at least one radiation passage (30, 35) is formed from glass or transparent plastic.
14. Household appliance (1) according to one of claims 7 to 13, characterised in that the at least one radiation passage (30, 35) is arranged on the end face, rear face, or lateral area of the drum (3).
15. Household appliance (1) according to one of claims 7 to 13, characterised in that the at least one radiation passage (30, 35) is formed as an axially symmetrical transparent protrusion which projects into the interior of the drum (3) from the rear side of the drum (3), wherein the axis of symmetry of the protrusion lies on the axis of rotation of the drum (3) and the rear side of the protrusion which faces away from the drum interior has a non-transparent layer which, in a concentric arrangement in respect of the axis of rotation of the drum (3), has at least one opening in order to permit incident radiation through the opening and the transparent protrusion into the drum interior.

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