Cleaning and liquid contact with solids – Processes – Combined
Reexamination Certificate
1999-02-17
2002-10-15
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Processes
Combined
C134S025100, C134S025200, C134S05600D, C134S0570DL, C134S0580DL
Reexamination Certificate
active
06464798
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a method and a device for the treatment of dishes in dishwashers.
The purpose of treating dishes in dishwashers is to remove dirt and crud from the articles to be cleaned. A washing liquid is generally used for this purpose. The washing liquid is mixed with cleaning agents and is preferably sprayed under pressure and at an elevated temperature onto the articles to be cleaned. In the course of a washing program, the washing liquid absorbs the dirt to be removed. Thus the washing liquid becomes thicker and the cleaning-active substances of the cleaning agents are being used up. As a result, the cleaning effect of the washing liquid decreases. Furthermore, where aqueous washing liquids are concerned, the lime content or mineral content of the water also reduces the cleaning effect of the washing liquid due to a partial precipitation of cleaning-active substances.
In order to determine the properties or the state of the washing liquid more accurately, optical turbidity sensors have been proposed for dishwashers. Such sensors are known for instance from the German published patent applications DE 42 43 868 A1, corresponding to U.S. Pat. No. 5,818,063 to Wilhelmstatter et al., and DE 196 11 402 A1. These optical turbidity sensors use light that is sent through the washing liquid. An optical receiver receives the radiation quantity transmitted in a straight line through the washing liquid. These known sensors respond to the turbidity of the washing liquid. With these sensors it is however not possible to determine more precise characteristics of the washing liquid, in particular relating to the type and quantity of its dirt components and/or cleaning agent components, so that this information also cannot be taken into account in controlling the washing program.
A dishwasher having a sensor unit for dirt in a circulated washing liquid is also known from the U.S. Pat. No. 3,888,269. The sensor unit includes an element transmitting optical signals and an element receiving optical signals. The sensor unit is arranged under a transparent portion of a horizontal shoulder of a treatment vessel, the transparent portion being surrounded by an upstanding rim.
Despite the movement of the circulated washing liquid, deposits of dirt particles may accumulate on the horizontal shoulder of the treatment vessel. Particularly the upstanding rim of the transparent portion causes dirt particles to accumulate precisely in the region in which the sensor unit is measuring. The washing liquid remaining on the horizontal shoulder evaporates. Due to the high temperatures in the dishwasher during the washing program cycle, the evaporation is even advanced. Depending on the degree of hardness of the washing liquid used, a lime deposit occurs when the remaining washing liquid evaporates. Particularly the upstanding rim of the transparent portion described above leads, in the region in which the sensor unit is measuring, to accumulations of the washing liquid which leaves behind lime deposits in the measuring region of the sensor unit during evaporation. Deposits of lime and accumulations of dirt particles on the transparent portion lead to false measurement result of the sensor unit. On the horizontal shoulder of the treatment vessel described above, a proper exchange or circulating of the washing liquid does not take place, so that the degree of dirt actually present in the washing liquid is not detected. As a result, the sensor unit generates false measurements. Particularly the upstanding rim of the transparent portion described above leads, precisely in the region in which the sensor unit is measuring, to accumulations of washing liquid which, if they remain for a relatively long time, do not have the degree of dirt actually present in the washing liquid, thus leading to false measurement results of the sensor unit.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and a device for the treatment of dishes in dishwashers which overcomes the above-mentioned disadvantages of the heretofore-known methods and devices of this general type and, in which, by means of an optical method, more accurate data on the dirt components and/or cleaning agent components of the washing liquid can be determined and taken into account in the optimization or control of the washing program. With the foregoing and other objects in view there is provided, in accordance with the invention, a method for treating dishes in a dishwasher, which comprises: radiating a radiation into a washing liquid in a given direction; detecting a radiation quantity of a radiation emerging from the washing liquid at a given angle with respect to the given direction for at least a given wavelength range; determining data including at least one of a type, a concentration, and a prevailing size of at least one of a dirt component, a cleaning agent component, and suspended particles in the washing liquid on the basis of the detected radiation quantity of the emerging radiation; and optimizing a washing program with the determined data.
In accordance with a further feature of the invention, the given wavelength range is substantially a wavelength range of a single wavelength.
In accordance with a further feature of the invention, the step of detecting includes detecting the radiation quantity of the radiation emerging from the washing liquid substantially in the given direction, and the step of determining data is further based on a radiation quantity of the radiation radiated into the washing liquid.
In accordance with a further feature of the invention, the step of detecting includes detecting the radiation quantity of the radiation emerging as a scattered radiation from the washing liquid substantially perpendicular to the given direction, and the step of determining data is further based on a radiation quantity of the radiation radiated into the washing liquid.
In accordance with a further feature of the invention, the step of detecting includes detecting the radiation quantity of the radiation emerging as a backscattered radiation from the washing liquid substantially opposite to the given direction, and wherein the step of determining data is further based on a radiation quantity of the radiation radiated into the washing liquid.
In accordance with a further feature of the invention, the radiation radiated into the washing liquid includes at least the given wavelength range, and the radiation quantity of the radiation emerging from the washing liquid is determined by at least one broadband radiation receiver sensitive to a wide wavelength range including the given wavelength range.
In accordance with a further feature of the invention, the radiation radiated into the washing liquid is generated by a plurality of radiation sources, the given wavelength range including a plurality of partial wavelength ranges, and the given partial wavelength ranges is generated by a respective one radiation source of the plurality of radiation sources.
In accordance with a further feature of the invention, the radiation radiated into the washing liquid includes at least the given wavelength range, and the radiation quantity of the radiation emerging from the washing liquid is determined by at least one radiation receiver sensitive to the given wavelength range.
In accordance with a further feature of the invention, the radiation radiated into the washing liquid is generated by a broadband radiation source generating all wavelength ranges to be emitted.
In accordance with a further feature of the invention, the radiation radiated into the washing liquid is emitted in at least one wavelength range, in which the at least one of a dirt component, a cleaning agent component, and suspended particles in the washing liquid causes at least one of a pronounced attenuation and scattering of the radiation radiated into the washing liquid.
In accordance with a further feature of the invention, the step of radiating the radiation into the washing liquid includes sequent
Bruchmüller Hans-Georg
Hering Reinhard
Reiter Bruno
Rosenbauer Michael
BSH Bosch und Siemens Hausgeräte GmbH
Greenberg Laurence A.
Locher Ralph E.
Markoff Alexander
Stemer Werner H.
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