Dishwasher comprising a sensor unit for determining a rotation movement of a spray arm

Abstract

The invention proposes a dishwasher comprising a working chamber, comprising at least one spray arm which is arranged in a rotatable manner in the working chamber, and comprising a metering apparatus for supplying and metering a substance, such as detergent, rinse aid etc., into the working chamber, which metering apparatus is designed as an insert part comprising a housing for insertion into a recess in an inner wall of the working chamber, for example in the door of the working chamber, and comprising a sensor unit for identifying a spray arm movement in the working chamber of the dishwasher, which sensor unit is arranged at least partially in a housing of the metering apparatus, wherein the sensor unit 11 comprises at least one infrared transmitter 12 and/or one infrared receiver 13.

Claims

1. A dishwasher comprising a working chamber, comprising at least one spray arm which is arranged in a rotatable manner in the working chamber, and comprising a metering apparatus for supplying and metering a substance, such as detergent, rinse aid etc., into the working chamber, which metering apparatus is designed as an insert part comprising a housing for insertion into a recess in an inner wall of the working chamber, for example in the door of the working chamber, and comprising a sensor unit for identifying a spray arm movement in the working chamber of the dishwasher, which sensor unit is arranged at least partially in a housing of the metering apparatus, characterized in that the sensor unit 11 comprises at least one infrared transmitter 12 and/or one infrared receiver 13.

2. The dishwasher according to claim 1, characterized in that the spray arm 5, 6 and/or a jet of water or washing solution from a spray nozzle crosses the beam path of the infrared transmitter 12 and/or infrared receiver 13 during the rotation of the spray arm.

3. The dishwasher according to claim 1 wherein the spray arm 5, 6 comprises a reflector for infrared light.

4. The dishwasher according to claim 1 wherein the housing 19 of the metering apparatus 9 is of water-tight design.

5. The dishwasher according to claim 3 wherein the housing 19 of the metering apparatus 9 has guide elements 20 in order to keep the beam path of the infrared light at least partially free of water running off from the housing.

6. The dishwasher according to claim 5 wherein the guide elements are designed as a roof 20 over an infrared-permeable passage in the housing 19 of the metering apparatus 9.

7. The dishwasher according to claim 1 wherein the inner wall of the working chamber has guide elements in order to keep water which is running off away from the beam path of the infrared light.

8. The dishwasher according to claim 1 wherein the sensor unit 11 is arranged such that it is not situated directly in a jet of water from a spray arm nozzle.

9. The dishwasher according to claim 3 wherein a time sequence of the sensor signal is detected and an evaluation unit is provided in order to detect the periodicity or frequency of the sensor signal which is induced by the rotating spray arm.

10. The dishwasher according to claim 1 further comprising an analog evaluation circuit.

11. A metering apparatus for supplying and metering a substance, such as detergent, rinse aid etc., into the working chamber of a dishwasher according to one of the preceding claims, which metering apparatus is designed as an insert part comprising a housing for insertion into a recess in an inner wall of the working chamber, for example in the door of the working chamber, and comprises a sensor unit for identifying a spray arm movement in the working chamber of the dishwasher, which sensor unit is arranged at least partially in the housing, characterized in that the sensor unit comprises at least one infrared transmitter and/or one infrared receiver.

Description

[0031] An exemplary embodiment of the invention is illustrated in the drawing and will be explained in more detail below with reference to the figures.

[0032] Specifically:

[0033] FIG. 1 shows a schematic cross section through a warewasher comprising a spray arm,

[0034] FIG. 2 shows a plan view of the inside of the door of a 8 warewasher,

[0035] FIG. 3 is an illustration of a metering apparatus, and

[0036] FIG. 4 shows an example of a sensor signal which can be measured by means of an infrared transmitter and/or infrared receiver.

[0037] FIG. 1 schematically illustrates the warewasher 1 comprising a dishwashing chamber 2 in section. With dish racks 3, 4 are located in the dishwashing chamber 2, a spray arm 5, 6 being arranged in a rotatable manner beneath each of said dish racks.

[0038] A warewasher door 7 is fitted to the front side in a rotatable manner, as is indicated by a rotation axis 8. A metering apparatus 9 for adding dishwashing agent is located in the warewasher door 7.

[0039] A sump container 10 is located in the base of the warewasher 1, said sump container containing, for example, the customary filters and the water outlet.

[0040] FIG. 2 shows the arrangement of an infrared sensor unit 11 in the metering apparatus 9, which infrared sensor unit comprises an infrared transmitter 12 and an infrared receiver 13. The metering apparatus 9 is inserted into the warewasher door 7, as already described with reference to FIG. 1. The metering apparatus 9 comprises, in a customary manner, a flap 14 for closing a dishwashing agent chamber, an outflow opening 15 for metering rinse aid, and an inspection window 16 and a refilling opening 17 for the rinse aid.

[0041] The evaluation and control unit can also be arranged in the interior of the warewasher door, as indicated in FIG. 1. At the location of the evaluation and control unit 18 indicated in FIG. 1, said evaluation and control unit can be connected directly to the displays, buttons and other operator control elements required to operate the machine.

[0042] FIG. 3 illustrates a metering apparatus for installation into a warewasher door according to the invention, wherein a storage means 1 for receiving detergent is provided. This detergent is supplied to the cleaning chamber for the dishes in a controlled manner during the cleaning phase of the dishwasher. In the process, a cover 2 is opened, so that the detergent can run out or be washed out of the storage means 1. A roof-like projection 20 serves as a guide element in order to deflect water or washing solution which is running down.

[0043] The infrared sensor unit 11 is installed, for example, at the edge of the housing 19 of the metering apparatus

[0044] FIG. 4 illustrates, by way of example, a time sequence of an infrared sensor signal. The horizontal axis of the graph shows the time t, while the vertical axis illustrates the intensity I. The sensor signal S exhibits different peaks P1 to P5 which are each arranged periodically as a function of time. The respective time points t1 to t5 are marked by corresponding arrows.

[0045] The graph according to FIG. 4 shows, by way of example, two further peaks S1 and S2 which constitute interference signals which can be caused, for example, by undesired reflections at dripping water or the like.

[0046] These interference peaks S1 and S2 can be identified and eliminated by suitable evaluation by means of the evaluation unit 18. This evaluation can be configured, for example, in such a way that only periodically recurring signals P1 to P5 are perceived as real sensor signals, non-periodic signals however being perceived as interference signals. Another way of identifying the interference signals involves, for example, integrating the corresponding signal peaks with respect to time, as a result of which the area which is covered by the peaks is mathematically determined. Since an integral value is to be expected within a specific interval given regular sensor signals, other signals, such as the linear interference signals S1 and S2 for example, can be identified and ruled out in this way.

[0047] These exemplary methods of else further methods for identifying interference signals, for example by means of threshold values in respect of the intensity or the like, can be used on their own or else in combination with one another.

[0048] If a malfunction, for example a stationary spray arm or a spray arm which is rotating too slowly, is identified on the basis of the sensor signal, thio can be displayed to the operator in a display.

[0049] The warewasher according to the invention can also be controlled depending on the sensor signal. For example, the quantity of water and/or the pump pressure can be varied. Nozzles which are controllable in respect of the orientation of the jet and/or shape of the jet are also optionally conceivable.

LIST OF REFERENCE SYMBOLS

[0050] 1 Warewasher [0051] 2 Dishwashing chamber [0052] 3 Dish rack [0053] 4 Dish rack [0054] 5 Spray arm [0055] 6 Spray arm [0056] 7 Warewasher door [0057] 8 Rotation axis [0058] 9 Metering apparatus [0059] 10 Sump container [0060] 11 Infrared sensor unit [0061] 12 Infrared transmitter [0062] 13 Infrared receiver [0063] 14 Flap [0064] 15 Outflow opening [0065] 16 Inspection window [0066] 17 Refilling opening [0067] 18 Evaluation and control unit [0068] 19 Housing [0069] 20 Roof-like projection [0070] T Time [0071] I Intensity [0072] P1 Peak [0073] P2 Peak [0074] P3 Peak [0075] P4 Peak [0076] P5 Peak [0077] T1 Time point [0078] T2 Time point [0079] T3 Time point [0080] T4 Time point [0081] T5 Time point [0082] S1 Interference peak [0083] S2 Interference peak