dishwasher

Abstract

Dishwasher, in particular household dishwasher, with a washing container (2) providing a washing chamber (3) which serves to hold items (10) to be cleaned, with a spray device arranged in the washing container (2) for applying washing liquid (4) to items (10) to be cleaned, and with a sensor unit (7) which serves to detect turbidity of the washing liquid (4), characterized in that the sensor unit (7) has a camera (8) which at least partially detects the washing chamber (3) and a reference surface (12) arranged in the detection area (21) of the camera (8).

Description

[0001] The invention relates to a dishwasher, in particular a household dishwasher, with a washing container providing a washing chamber for receiving items to be cleaned, with a spray device arranged in the washing container for applying washing liquid to the items to be cleaned, and with a sensor unit for detecting turbidity in the washing liquid.

[0002] Dishwashers are fundamentally well known from the prior art, including in the special embodiment as program-controlled household dishwashers, so that a separate printed proof is not required at this point.

[0003] A dishwasher of this type has a wash tub, also called a drum, which provides a wash chamber. This chamber is accessible to the user via a loading opening, which can be sealed fluid-tight by means of a hinged wash chamber door. In normal use, the wash tub serves to hold items to be cleaned, such as dishes, cutlery, and / or the like.

[0004] To spray the items to be cleaned with cleaning fluid, the so-called wash liquor, the dishwasher has a spray system located inside the wash tub. This spray system provides rotatably mounted spray arms, typically two or three of which are provided. Under normal operating conditions, the items to be cleaned are sprayed with the wash liquor by means of rotating spray arms.

[0005] As a wash cycle progresses, the quality of the wash water deteriorates due to dirt particles detaching from the dishes being cleaned and accumulating in the water. This accumulation of dirt particles leads to cloudiness in the wash water. To enable the program to take appropriate measures when the wash water quality reaches a level that no longer guarantees the desired cleaning result, it is known in the art to equip dishwashers with a sensor unit for detecting the turbidity of the wash water. Known sensor units have a turbidity sensor that measures the turbidity of the wash water. Such a sensor is typically located in the sump and has a transmitting unit and a receiving unit, which are spaced apart from each other via an intermediate measuring section.The transmitter unit is, for example, an infrared LED, in which case the receiver unit is designed as a photodiode.

[0006] US patent 2007 / 0046942 A1 discloses a turbidity sensor for a dishwasher in which a light beam from a transmitting unit is directed through a liquid onto a reflective surface and the reflected beam is detected by a receiving unit.

[0007] EP 1 977 835 A1 discloses a surface cleaning device with an analysis device designed to acquire measured values ​​for image evaluation and the evaluation of color and / or brightness distributions.

[0008] Although turbidity measurement using established turbidity sensors has proven effective in everyday practical use, there are nevertheless disadvantages that should ideally be overcome. For example, placing a turbidity sensor in the collection tank is unfavorable because, during normal rinsing operation, air bubbles are created by flow turbulence, negatively impacting the quality of turbidity detection. Furthermore, the optical properties of a turbidity sensor are usually inadequate, as sufficient color resolution is not guaranteed. This means that different colored contaminants cannot be distinguished from one another. Since the receiving unit can only differentiate between transmitted and blocked signals from the transmitting unit, it is not possible to distinguish dirt particles in the rinsing solution according to type, size, shape, and / or other characteristics.Furthermore, it should be noted that the transmitting and receiving units are technically calibrated in such a way that only changes in the liquid within a specific wavelength range can be measured. All of this can lead to inaccuracies in the measurement results, which is why there is room for improvement.

[0009] Based on the foregoing, the object of the invention is therefore to propose a dishwasher of the type mentioned at the outset which enables improved turbidity measurement compared to the prior art, whereby misinterpretations of the measurement result are to be avoided in particular.

[0010] To solve this problem, the invention proposes a dishwasher of the type mentioned at the outset, which is characterized in that the sensor unit has a camera that at least partially detects the washing chamber and a reference surface arranged in the detection area of ​​the camera.

[0011] According to the invention, a sensor unit is used for turbidity measurement, rather than a turbidity sensor. This unit comprises a camera on one side and a corresponding reference surface on the other. This arrangement allows not only the detection of increasing turbidity in the wash liquor, but also the differentiation between individual dirt particles with regard to shape, size, color, and / or the like. This enables targeted adjustments to the wash program based on the detected contamination level. As a result of the wash liquor detection, an optimized wash program sequence can be achieved, which, in particular, ensures the desired cleaning result while simultaneously conserving resources.

[0012] The camera provided according to the invention, in its intended use, captures at least part of the washing chamber provided by the washing container. The reference surface interacting with the camera is arranged in the washing chamber, the relative positioning of the reference surface and the camera being selected such that the reference surface lies within the camera's field of view, and thus a photograph taken by the camera shows at least the reference surface.

[0013] In operation, not only the items being washed in the wash chamber but also the reference surface is exposed to the wash solution. The reference surface reacts to different levels and / or types of soiling by changing its optical properties, which are captured by the camera thanks to its position within the camera's field of view. These changes in the optical properties of the reference surface can occur due to chemical and / or biological reactions, or—preferably—due to changes in its reflective properties caused by substances that accumulate on or flow past the reference surface during the wash cycle.

[0014] The sensor unit provided according to the invention has a control unit or is connected to one via communication technology. In the intended application, this control unit enables demand-based control of, in particular, the camera, and possibly also any light sources. Depending on the detected level of contamination, the camera and / or any light sources can be readjusted.

[0015] The control unit has evaluation electronics. These are equipped with a comparison circuit, which analyzes and evaluates images taken by the camera, for example, by comparing them with reference images previously stored in the evaluation electronics. As a result of this evaluation, the operation of the dishwasher can then be adjusted programmatically if soiling is detected.

[0016] In the simplest case, the reference surface can be provided by the item being cleaned itself. This is particularly feasible if the item being cleaned has a uniform color. However, it is preferable to provide a reference surface separate from the item being cleaned within the washing container. According to a first embodiment of the invention, a plate is provided for this purpose, which is attached to a wall inside the washing container. Preferably, such a plate provides a white reference surface, thus enabling optimized contrast detection. Such a plate-provided reference surface can also be used in combination with a reference surface provided by the item being cleaned.

[0017] According to a further feature of the invention, the reference surface can be structured and / or colored. Accordingly, the reference surface provides a surface structure and / or a coloration, the advantage of which is to make dirt particles distinguishable from one another, particularly with regard to shape, size, color, and / or the like. For example, the coloration can serve to differentiate dirt particles by color, such as green dirt particles (spinach) from red dirt particles (tomato).

[0018] According to a further feature of the invention, the reference surface has sections that are structured differently and / or colored differently. An advantage of this design is that the detection spectrum is broadened, which allows for more detailed and therefore ultimately more meaningful dirt detection.

[0019] According to a further feature of the invention, the reference surface can be backlit. For example, the reference surface can be provided by a display. Designing the reference surface as a display has the particular advantage that the contrast and / or brightness of the reference surface can be adjusted, as well as, if necessary, color schemes and / or pattern representations, even during a washing program, and possibly also in a changing display.

[0020] The camera provided according to the invention can be a commercially available camera, for example a CCD or CMOS camera. A light source is required to illuminate the reference area captured by the camera. This light source is preferably one already installed in the washing chamber. Both the camera and the light source can be controlled by means of a control unit, which allows the light source to be switched on and off, being switched on when an image is being taken and off otherwise.

[0021] The camera can also be one that operates in the non-visible wavelength range, for example, an infrared camera. In this case, a light source with an adjustable spectral range is preferably used. This makes it possible to perform even more differentiated measurements by varying the wavelengths of the light emitted by the light source.

[0022] The light source is preferably equipped with an optical filter to minimize scattering and / or interference effects.

[0023] According to a further feature of the invention, the camera and the light source are designed as a single unit, which simplifies assembly or, in the case of repair, disassembly.

[0024] The design according to the invention makes it possible to determine the initial state of the dishwasher or the soiling level of the items to be cleaned, even during a cleaning cycle, thus enabling the monitoring of the washing or cleaning progress. This information, or a direct camera image, can be transmitted wirelessly, for example via WLAN, to a user, for instance using a mobile device such as a smartphone or tablet. Furthermore, the design according to the invention allows for the analysis of the washing process with regard to the type, shape, color, and size of the dirt particles and the optimization of program parameters accordingly, such as performing early changes of the wash water.

[0025] Further features and advantages of the invention will become apparent from the following description with reference to the figures. These show Fig. in schematic perspective view from the front of an opened dishwasher according to the invention; Fig. 2 in schematic view a reference surface according to the invention according to a first embodiment; Fig. 2b in lateral view the reference surface according to Fig. 2; Fig. 3 in schematic view a reference surface according to the invention according to a second embodiment; Fig. 3a in lateral view the reference surface according to Fig. 3; Fig. 4 in schematic view a reference surface according to the invention according to a third embodiment; Fig. 5a in schematic front view a dishwasher according to a first embodiment according to the invention; Fig. 5b schematic front view of a dishwasher according to a second embodiment of the invention; Fig. 5c in schematic front view a dishwasher according to a third embodiment of the invention; and Fig. Figure 6 shows a schematic side view of another embodiment of the invention.

[0026] Fig. Figure 1 shows a schematic perspective view of a dishwasher 1 according to the invention from the front with the dishwasher door 6 open.

[0027] The dishwasher 1 has, in a manner known per se, a wash container 2 which defines an interior space, the so-called wash chamber 3. This is accessible from the user via a loading opening 5, which can be closed in a fluid-tight manner by means of the rotatably mounted wash chamber door 6.

[0028] In its intended use, the wash chamber 3 serves to hold items 10 to be cleaned, which may include, for example, dishes, pots, cutlery, and / or the like. For the intended purpose of accommodating these items 10, the dishwasher 1 in the illustrated embodiment has two wash baskets 11.

[0029] To spray the items to be cleaned 10 with the cleaning solution 4, the dishwasher 1 has a spray device (not shown in detail in the figures). This spray device is fluidically connected to a circulation pump of the dishwasher 1 (not shown in detail), which supplies the spray device with the cleaning solution 4.

[0030] During a standard wash cycle, contaminants, particularly dirt particles, accumulate in the wash water 4 as they detach from the items being cleaned 10. In normal use, the wash water 4 thus becomes contaminated. As the wash water 4 becomes increasingly contaminated, its cleaning performance decreases. Therefore, it is desirable to be able to adjust or readjust the program control depending on the degree of contamination of the wash water 4. For this purpose, the dishwasher 1 according to the invention has a sensor unit 7 that serves to detect the turbidity, i.e., the contamination, of the wash water 4.

[0031] According to the invention, the sensor unit 7 has a camera 8 and a reference surface 12 arranged in the detection area 21 of the camera 8 in the intended use.

[0032] In the illustrated embodiment according to Fig. In the embodiment shown, the camera 8 is arranged on the inside of the wash chamber door 6, so that, when the door 6 is fluid-tight during operation, the camera 8 at least partially captures an image of the wash chamber 3. The reference surface 12 lies within the detection area 21 of the camera 8 and thus interacts with it. In the illustrated embodiment, the reference surface 12 is provided by the surface of a plate 13 arranged on the rear wall 14 of the container. The plate 13 could, for example, be a white plastic plate.

[0033] In its intended use, not only the items to be washed 10, but also the reference area 12 is supplied with washing solution 4. This is shown schematically in the following figures. Fig. 2 and Fig. 2a according to a first embodiment as well as the Fig. 3 and Fig. 3a shown according to a second embodiment.

[0034] The reference surface 12, which may be wetted with the potentially contaminated cleaning solution 4, is imaged using camera 8. In an evaluation unit, the image created by camera 8 can be compared, for example, with a reference image, and thus the degree of contamination of the cleaning solution 4 can be determined. Based on the image acquisition, contaminants present in the cleaning solution 4 can be distinguished according to size, type, shape, color, and / or similar characteristics, thus enabling detailed and specific contamination detection.

[0035] How the embodiments according to the Fig. 2, Fig. 2a, Fig. 3 and Fig. As shown in Figure 3a, the reference surface 12 is preferably subdivided into sections 15 with different structures and / or colors. This subdivision makes it possible to specifically identify different dirt particles based on their shape, color, size, and / or other characteristics.

[0036] According to the embodiment according to the Fig. 2 or 2a, the plate 13 providing the reference surface 12 is arranged directly on the rear wall 14 of the container, as shown in particular in the detailed illustration according to Fig. 2a can be seen. The plate 3 is tapered upwards with respect to the drawing plane, thus creating a chamfer that reduces the flow of the fleet 4. This allows for improved image acquisition by the camera 8.

[0037] According to a second embodiment, as described in the Fig. 3 and Fig. As shown in Figure 3a, the plate 13 providing the reference surface 12 is positioned at a distance from the rear wall 14 of the container, leaving a gap 16. In the intended use, the cleaning solution 4, which is to be imaged by the camera 8, flows through the gap 16 between the rear wall 14 of the container and the plate 13. For the purpose of image recording of the cleaning solution 4 by the camera 8, the plate 13 is transparent or semi-transparent according to this embodiment.

[0038] According to a first embodiment of the invention, the camera 8 used operates in the visible wavelength range. Therefore, a light source 9 is required for image acquisition, which can, for example, be housed in one of the container's side walls, as shown in the illustration. Fig. 1. Preferably, the light source 9 is a light source already provided by the dishwasher 1, which serves to illuminate the washing chamber 3 for the user when the dishwasher door 6 is open.

[0039] The light source 9 can be operated continuously or in pulsed mode. In particular, a stroboscopic operation of the light source 9 is conceivable, which, in combination with the camera 8, allows the determination of the flow velocities of the flushing solution 4, thus also enabling conclusions to be drawn about the type and extent of the flushing solution contamination.

[0040] Another embodiment allows Fig. 4. According to this variant, a display 17 is used as a backlit plate 13, providing the reference surface 12 on its front. The display 17 preferably has variable surface areas 15. Instead of a display 17, a color-changing surface, for example an LED light panel, can also be used. The display 17 can be changed with regard to color, brightness, and / or the like, even during a program sequence. In the intended use, the camera 8 records the water films flowing over the display 17 during the rinsing process, along with the dirt particles contained therein, and the evaluation unit can assign the recorded images to a specific type of dirt particle based on the determined size, shape, color, and / or color-changing properties.

[0041] The Fig. Figures 5a to 5c illustrate different configurations in the execution. Fig. Figure 5a shows an embodiment in which the dishwasher is equipped with a display 17 according to Fig. 4 is equipped. Fig. Figure 5b showed an embodiment in which the reference surface 12 is provided by a plate 13 which is of a single color, for example white. Individual dirt particles 18 are particularly easy to see against a single-color background.

[0042] Fig. 5c shows one to Fig. 5a modified embodiment. According to this embodiment, the reference surface 12 includes not only the surface of the plate 13, but also the surfaces of the items being washed 10 themselves. Including the items being washed 10 also makes it possible to determine the cleaning progress, i.e., not only to detect the development of soiling in the washing solution, but also to monitor the cleaning result. Furthermore, with the embodiment according to Fig. 5c provides that the plate 13 provides a reference surface 12 which is divided into individual sections 15, each of which provides different reflection properties, whether through different surface structuring and / or coloring.

[0043] Fig. Figure 6 reveals a further embodiment. According to this embodiment, a camera 8 is used in combination with light sources 19 that emit light in the wavelength range of, for example, 300 nm to 1000 nm. Such light sources 19 can, for example, be IR LEDs.

[0044] The light sources 19 are located in close proximity to the camera 8. A reference surface 12 located on the opposite side of the wash chamber 3 is tuned to this spectral range or is reactive by means of a corresponding optical filter 20. During the wash cycle, the light sources 19 are switched on. Several different spectral ranges can be emitted by the light sources 19. The camera 8 records images accordingly, with different color gradients appearing in the image depending on the level of soiling. The control unit evaluates this and assigns corresponding parameters to the further wash cycle based on the detected type of soiling.

[0045] Overall, the inventive design enables the detection of different types of dirt and dirt particles. The arrangement according to the invention is insensitive to air bubbles and significant changes in the turbidity of the cleaning solution. The detection of soiling on the items being cleaned 4 is possible during the cleaning process. This also allows for an assessment of the current cleaning success. The measurement results can be clearly displayed on a user-side receiving device, such as a smartphone, using a graphic, video sequence, or images taken by the camera 8. The ongoing cleaning cycle can also be streamed directly to such a mobile device upon request. Reference sign 1 dishwasher 2 washing containers 3. Dishwashing area 4. Rinsing water 5 Loading opening 6 door 7 Sensor unit 8 Camera 9 Light source 10 items to be washed 11 Dishwashing basket 12 Reference area 13 plate 14 Container wall Section 15 16 columns 17" Display 18 dirt particles 19 Light source 20 optical filters 21. Detection area

Claims

[1] Dishwasher, in particular a household dishwasher, with a washing container (2) providing a washing chamber (3) for receiving items (10) to be cleaned, with a spray device arranged in the washing container (2) for spraying items (10) to be cleaned with washing solution (4), and with a sensor unit (7) for detecting turbidity of the washing solution (4), characterized by , that the sensor unit (7) has a camera (8) that at least partially detects the washing chamber (3) and a reference surface (12) arranged in the detection area (21) of the camera (8). [2] Dishwasher according to claim 1, characterized by , that the reference surface (12) is a surface of an item to be cleaned (10). [3] Dishwasher according to claim 1, characterized by , that the reference surface (12) is provided by a surface of a plate (13) arranged in the rinsing tank (2). [4] Dishwasher according to any one of the preceding claims, characterized by , that the reference surface (12) is structured. [5] Dishwasher according to any one of the preceding claims, characterized by , that the reference surface (12) is colored. [6] Dishwasher according to any one of the preceding claims, characterized by , that the reference surface (12) has sections (15) which are structured differently and / or colored differently. [7] Dishwasher according to any one of the preceding claims, characterized by , that the reference surface (12) is backlit. [8] Dishwasher according to any one of the preceding claims, characterized by a light source (19) whose spectral range is adjustable. [9] Dishwasher according to claim 8, characterized by that the light source (19) is equipped with an optical filter (20). [10] Dishwasher according to claim 8 or 9, characterized by , that the camera (8) and the light source (19) form a single unit.

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