EP1116471A2 - Method and device for determining the amount of dirt on tableware - Google Patents

Abstract

A dishwasher (1) with a rinsing container (2) for cleaning a good (30) to be cleaned has transmitting elements (31) and receiving elements (32) in order to radiate electromagnetic radiation onto the good (30) and to receive reflected / transmitted radiation, to get information about the type and strength of impurities. <IMAGE>

Description

The invention relates to a method for determining the pollution of a Good to be cleaned using electromagnetic radiation, in which the radiation Contains wavelengths caused by contaminants on the surface of the surface to be cleaned Guts are absorbed, in which those reflected and / or transmitted by the dishes Radiation is measured, and in which from the reflected or the transmitted Radiation on the type and / or the amount of contaminants on the dishes is closed.

The invention also relates to a dishwasher for cleaning one to be cleaned Guts or a testing device for testing one to be cleaned or one cleaned Guts with a device for detecting contamination on the to be cleaned or the cleaned good.

The aim of treating dishes in a dishwasher is to remove contaminants from them to remove the goods to be cleaned. For this purpose, a liquid washing liquor is generally used used, which is mixed with cleaning agents and especially at elevated temperatures is sprayed onto the items to be cleaned under pressure.

It is already known, for example from DE 198 06 559 A1, optical turbidity sensors use for dishwashers where electromagnetic radiation is in a Rinsing liquor is blasted in, preferably for at least one wavelength range a wavelength, the amount of radiation under each predetermined Angle emerging radiation is determined, from which the Art and the concentration of contaminants and / or detergent components in the wash liquor are determined and the wash program based on these determined data is optimized.

The parameters of the radiation emerging again are, for example, the Radiation amount or intensity, color or wavelength, polarization or that Spectrum of the scattered radiation determined. The one that comes out again Radiation amount or intensity depending on the amount of radiation radiated into it be determined and so standardized, in particular one for further evaluation easy to handle size.

A disadvantage of the known method is that the dishes are not soiled is detected. The increasing pollution of the washing liquor is only an indirect indication on cleaning. It can be seen that in the course of the rinsing process Rinsing liquor is increasingly contaminated, which also causes The cleaning effect of the washing liquor decreases, but it cannot be determined whether the dishes is actually cleaned of all contaminants, or whether contamination is on have remained on its surface.

It is the object of the invention to provide a method by which the contamination of the dishes can be determined precisely. This object is, as in claim 1 specified, solved.

It is also the object of the invention to set up a method according to this method Dishwasher and a test device for determining the soiling of dishes to accomplish. This object is, as stated in claim 3, solved.

A particular advantage of the invention is that the use of electromagnetic Radiation and by directly irradiating the dishes themselves precise information about the type and strength of the contaminants on the surface of the Dishes can win. Any kind of pollution, such as margarine, egg yolk, Spinach, oatmeal, minced meat, milk and tea exhibit when irradiated with light, for example with infrared light, characteristic absorption lines on, so that in the reflection spectrum at these wavelengths attenuations in the intensity of the reflected Signal result, the weakening is a measure of the strength of the pollution.

Thus, from the signal intensity of the reflected light to the initial or deduce the remaining amount of each type of dirt.

If so, for example at the beginning of the washing process in a dishwasher, first through Irradiation of the dishes in a wavelength range in which the absorption of certain Wavelengths due to the contamination can be expected, light on the dishes is radiated and reflected light is measured, can be repeated recognize this measurement process during the rinsing process, like the cleaning process is advanced. In particular, it can also be based on the reflection spectrum Start of the rinsing process, set how much detergent the Rinse liquor must be added to the one hand based on the type of soiling and on the other hand, based on the amount of the respective soiling, the amount to optimize the detergent. In addition, according to the type and Intensity of contamination also optimize the temperature at which the washing liquor acts on the goods to be cleaned. It is also possible with the help of pollution of the dishes obtained, the rotational speed of the Spray arm and the amount of water it sprayed onto the dishes, d. H. the mechanical Treatment, control or regulate.

According to the invention, both a method for determining the pollution as well as a method of washing dishes in a dishwasher as well a device for determining the pollution and one with such Device equipped dishwasher created.

Further advantages result from the subclaims in connection with the description.

Any transmission element is suitable for emitting the electromagnetic radiation radiation in the wavelength range relevant for the detection of pollution emits, for example an incandescent lamp, a halogen lamp, a mercury vapor lamp, a light emitting diode, a laser diode, a gas laser or the like. Especially suitable are transmitters which emit a narrow-band spectrum, or transmitters that produce monochromatic light. These are monochromatic or narrowband Suitable transmitters in connection with one or more receivers, these can be broadband, provided that they only the bandwidth of the transmitter or the Transmitters include radiation emitted. Alternatively, broadband radiators can be used and use assigned wavelength-selective receivers. Instead of wavelength selective Broadband transmitters and / or receivers can also be used, if narrowband filters are assigned to either the transmitters or the receivers are.

A plurality of transmitter elements is preferably also used, these being either different spectra or monochromatic light of different wavelengths produce. The receiving elements are correspondingly adapted to the transmitting elements. Photodiodes or phototransistors are particularly suitable as receiving elements. If the transmitting element emits radiation in several wavelengths, it is preferred a plurality of receiving elements, in particular photodiodes, for example used with an upstream filter or grid, or a photodiode array or CCD's (Charged Coupled Devices) that absorb light and corresponding electrical Generate signals, which are preferably amplified and fed to an evaluation circuit become.

Essentially, the dishes are reflected to determine the level of contamination Radiation exploited, but also the use of transmitted radiation is not excluded, provided the dishes are transparent to the radiation, for example in the infrared or ultraviolet range.

An evaluation circuit obtains information for an operator from the measurement signals or customer service. When testing in a test device, the information for Check of a rinsing process used.

In an advantageous development of the invention is a movably arranged receiving device provided with which the goods to be cleaned in the manner of a scanner is driven. This also allows location information about the soiling receive. The movable arrangement is, for example, by means of a movable prism or mirror realized. The receiving element on the spray arm is advantageous appropriate.

If a plurality of receiving elements are present, the radiation that is reflected integrally over the space, and, for example, over the measured one Integrated solid angle, evaluate.

Transmitting and receiving elements are preferably used in connection with optical devices, in particular focusing lenses, optical fibers and optical and / or electrical arrangements used to amplify optical or electrical signals.

Filters are also advantageously used to separate out narrow spectral ranges. Diffraction gratings are suitable for this, for example, at different angles different wavelengths are transmissive, prisms, holographic filters, gratings and the like. Optical fibers are preferably also used, which allow Transmitting and receiving elements on a low thermal and / or mechanical Place exposed to loads within the dishwasher or testing device arrange and the electromagnetic radiation in the area where the dishes is cleaned, via an optical fiber coupling and / or out of this area to lead to the receiving element via an optical waveguide.

The use of optical fibers has the further advantage that high temperatures, which are often be used when washing dishes, the optical elements such. B. the broadcast and receiving elements themselves and the optical means assigned to them, not influence, so that no measures are necessary to temperature fluctuations to compensate for or compensate for the transmitting and / or receiving elements.

Another advantage of this is that there are inexpensive transmitting and / or receiving elements can be used that have lower requirements for temperature stability and therefore have to be less stable against the influences as they occur within a rinsing container to rule. A protective glass can preferably also be provided, the transmission and / or Shields receiving elements from the rinsing container and preferably can be removed by the user so that it can be cleaned.

There is also preferably an automatic comparison between a transmission signal and a received signal in the absence of the dishes to be cleaned, so that Errors resulting from contamination, such as on the transmitting and / or receiving element or remain on the shielding protective glass, with a subsequent one Measurement on the dishes as difference signals from the signals then measured in Deduction can be brought. The transmitting and / or receiving elements can be for example, calibrate each time the device is switched on.

Various properties of the spectra are suitable for evaluating the spectra, for example, their slope, the height of the peaks, the height ratio of different ones Peaks, derivation functions from the spectra, as quantities obtained from the spectra. A factor analysis of the spectra is preferably also carried out. Everyone there The data obtained can be stored in the storage unit and are then available Comparison with later measurement results available. This is in the evaluation circuit also recognized the amount of pollution present to the amount of the detergent to be dosed accordingly. If the evaluation circuit also determines which dirt is mainly present on the items to be cleaned and if there are several cleaning agents suitable for different types of dirt Are available, the evaluation circuit also determines the amount in each case the detergent suitable for the pollution must be dosed.

In a particularly preferred embodiment of the invention, the evaluation unit comprises a fuzzy logic or a neural network in which different spectra or parts of spectra for the detection of permanent properties of contaminants are. Spectra are preferably for different types of soiling on the dishes in a storage unit before or during operation of the tester or the dishwasher is successively stored so that it can then be used when checking the cleaning status of dishes or when cleaning Cleaning dishes in the dishwasher must be taken into account.

In the following, the invention is illustrated in an exemplary embodiment with reference to the single figure explained in more detail.

This shows a dishwasher in cross section.

A dishwasher 1 according to the invention (FIG. 1) has a washing container 2, in the dishes to be cleaned 30, d. H. to be cleaned in the dishwasher 1 Good, for example in the form of plates, pots, cutlery, etc., usually in baskets 3, 4 is filled. Two spray devices 5, 6 are arranged in the washing container 2, to apply liquid to the material 30 to be cleaned. This liquid, Usually called rinsing liquor, is in a liquid pump by means of a circulation pump 7 8, 9 transported to the spray devices 5, 6.

The liquid conveyed in dishwashers 1 is usually at least in a sub-program section of a washing program heated, for which a water heater 10 serves. The pumped liquid is from the circulation pump 7 to an inlet connection 11 of the instantaneous water heater 10 and passed through the instantaneous water heater 10. This has at least two outlet ports 12, 13, of which the liquid via the Liquid feed lines 8, 9 are fed to the respective spray devices 5, 6. In the heater 10 is arranged a heater, not shown here.

In order to measure the contamination of the dishes 30, inside the wash cabinet 2 Transmitting elements 31 and receiving elements 32 are arranged. From the sending elements 31 electromagnetic radiation is radiated onto and from the dishes 30 reflected on the receiving elements 32. The transmitting and receiving elements 31, 32 are each connected via lines 33 and 34 to an evaluation circuit 35 in which a Comparison between the transmitted and the received spectra is made. Based the pollution-specific absorption of electromagnetic radiation can be based on the type of impurities and the intensity of the absorption deduce the amount of the respective impurities.

Since preferably a plurality of transmission elements 31 are located on the inside of the washing compartment 2 delimiting walls 15, 16 are distributed, can be at least a part of in the dishwasher 1 Detect inserted dishes 30. Based on the whole irradiated surface of the dishes 30 can then the evaluation circuit 35 by Contamination covered area of the dishes 30, based on the total area of crockery parts 30. The reflected radiation can also be transmitted through the receiving elements Split 32 upstream filters, in particular optical gratings, that the individual receiving elements 32 each have different spectral components of the reflected radiation, wherein the receiving elements 32 are preferably from Diodes, for example silicon or InGaAs diodes, are formed.

The method described above can also be used in a test device by means of its washing and washing processes in different dishwashers compared become. This allows objective information about the quality of washing processes to reach. In the test device, either that is already from a dishwasher cleaned good then examined whether it already had the required degree of cleaning to thereby evaluate the cleaning result of the dishwasher, or the dishes to be cleaned are examined.

The invention can be used both before the start of a rinsing process to control the amount of the cleaning agent, the temperature, the amount of cleaning liquid to be used, adjust the rotational speed of the spray arms 5, 6, as well as during the rinsing process to make a comparison between the initial contamination and the current pollution, in order to make a statement about the further duration of the Rinsing process or other measures still to be taken during the rinsing process to get to the desired cleaning result.

Claims (13)

Method for determining the contamination of a good to be cleaned (30) using electromagnetic radiation at which the radiation has wavelengths contains, due to contamination on the surface of the goods to be cleaned (30) are absorbed, in which the reflected from the items to be cleaned and / or transmitted radiation is measured and in which the reflected or the transmitted radiation on the type and amount of impurities on the estate (30) is closed. Method according to claim 1, characterized in that the material to be cleaned before a rinsing process and / or during a rinsing process with electromagnetic Radiation is irradiated and that from the material to be cleaned (39) reflected and / or transmitted radiation for the presence of contaminants on the estate (30) is concluded and that the duration or the remaining duration of the rinsing process, the temperature to be used, the amount of detergent to be added and the type of mechanical treatment is determined. Dishwasher (1) for cleaning a good or test device to be cleaned for checking a good to be cleaned or a cleaned good (30) with a device to detect contaminants on the to be cleaned or cleaned good (30), the device at least one transmitting (31) and at least a receiving element (32) for transmitting or receiving electromagnetic Radiation and an evaluation circuit connected to the receiving element (32) (35), the one transmitted by the transmitting element (10) and reflected and / or transmitted from the good (30) to be cleaned or cleaned Radiation can be received by the receiving element (32) and in the evaluation circuit (15) can be evaluated. Dishwasher (1) or testing device according to claim 3, characterized in that that the transmitting element (31) is a broadband radiator, in particular a Light bulb, a halogen lamp or a light emitting diode. Dishwasher (1) or testing device according to claim 3 or 4, characterized in that that the receiving element (32) is a narrowband receiver, is in particular a photodiode or a phototransistor. Dishwasher (1) or testing device according to one of claims 3 to 5, characterized characterized in that the receiving element (32) as an array of a plurality is formed by receiving components. Dishwasher (1) or testing device according to one of claims 3 to 5, characterized characterized in that the receiving element (32) consists of a plurality of Charged Coupled Devices (CCD's) exist. Dishwasher (1) or testing device according to one of claims 3 to 7, characterized characterized in that the transmitting element (31) and / or the receiving element (32) with a coupling in or out coupling the electromagnetic radiation optical component, in particular a focusing lens is. Dishwasher (1) or testing device according to one of claims 3 to 8, characterized characterized in that the receiving element (32) with an optical filter, a diffraction grating or a prism for spectral decomposition of the incident electromagnetic radiation is equipped. Dishwasher (1) or testing device according to one of claims 3 to 9, characterized characterized in that the transmitting element (31) or the receiving element (32) with an optical waveguide for decoupling or for coupling the electromagnetic Radiation is equipped. Dishwasher (1) or testing device according to one of claims 3 to 10, characterized characterized in that the evaluation circuit (34) with a memory (35) for saving specified spectra for calibration purposes or for saving measured spectra is connected. Dishwasher (1) or testing device according to one of claims 3 to 11, characterized characterized in that the evaluation circuit (34) a fuzzy logic and / or a neural network. Dishwasher (1) or testing device according to one of claims 3 to 11, characterized characterized in that the receiving element (32) is movably arranged and the goods to be cleaned or cleaned (30) by the receiving element (32) is scannable.

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