Dishwashing Machine With Heating Control

Abstract

A dishwashing machine for commercial use to clean items cyclically has at least one tank for holding a dishwashing liquid, as well as at least one heating apparatus for heating the dishwashing liquid, and at least one temperature sensor for detecting the temperature of the dishwashing liquid. The dishwashing machine also has a controller being designed in order to control heating of the dishwashing liquid in at least one program step in a dishwashing program, with the heating being carried out at least until a predetermined intended temperature is reached. In this case, before or during an initial heating phase, a start temperature of the dishwashing liquid is detected, the minimum heating duration being determined from the start temperature. The heating process is then carried out accordingly with this minimum duration.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is based on German Patent Application No. 10 2007 005 834.0 filed 1 Feb. 2007, upon which priority is claimed, and on Provisional Application 60 / 907,302 filed on Mar. 28, 2007.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a dishwashing machine for commercial use, and to a method for controlling a dishwashing machine for commercial use.[0004]2. Prior Art[0005]Commercial dishwashing machines are used in various areas in which relatively large amounts of items to be cleaned have to be cleaned within a short time. These items to be cleaned may, in particular, be in the form of glasses, flatware, plates and dishes, containers, trays, saucepans and cooking pans, kitchen utensils or similar other objects. It is also feasible to clean other types of items to be cleaned, in particular including items from other areas than the area of large kitchens. However, in particular, machines such a...

AI Technical Summary

Benefits of technology

[0011]The object of the present invention is therefore to propose a dishwashing machine as well as a method for controlling this dishwashing machine, which avoid the disadvantages described above of the prior art, and which is designed in order to achieve cycle times which are as short as possible and at the same time to minimize the use of heating energy.

[0023]The described dishwashing machine and the described program in one of the described refinements has the advantage over the dishwashing machines and methods know from the prior art that a predetermined intended temperature can be reached reliably and quickly. This makes it possible, for example, to safely comply with hygiene parameters in accordance with the relevant Standards and Regulations. Examples of Standards such as these are: DIN 10511: Foodstuffs hygiene, commercial dishwashers with glass washing machines; DIN 10512 Commercial dishwashers with single-tank dishwashing machines; DIN 10522: Foodstuff hygiene, commercial machine washing of multiple-use boxes and multiple-use containers for unpackaged foodstuffs; EN ISO 15883-1: Cleaning and disinfection appliances; NSF / ANSI Standard 3: Commercial Warewashing Equipment (USA), hygiene test with thermo-label. Furthermore, overall, the proposed dishwashing machine makes it possible to greatly improve, and therefore optimize, the washing and final washing result. During the process, the items to be cleaned are dealt with carefully.

[0024]As described above, the dishwashing machine can advantageously in particular have at least one washing tank and one circulation device for initial cleaning of the items to be cleaned, as well as at least one final washing tank for final washing of the items to be cleaned. As mentioned initially, this has the advantage that (in contrast to domestic appliances), heating processes can be carried out in parallel.

[0026]Use in the final washing tank has the advantage, for example, that the best final washing result is achieved at a high temperature. Furthermore, subsequent drying of the items to be cleaned is greatly improved. In addition, the final washing water is in many case introduced into the washing tank after use, this avoids the washing tank being cooled down by excessively cold final washing water. A further advantage is that the final washing liquid in many cases has additives mixed with it which, for example, allow the items to be cleaned to be wetted better. However, the effect on these additives is temperature-dependent. If the temperature of the final washing liquid is chosen to be too low, then this results in poorer wetting of the items to be cleaned, and possibly in the formation of foam.

[0027]The application of the described principle to the heating of the washing tank has the advantage that it is possible to optimize the washing effect and the washing result, which is generally ensured only at the correct temperature. In particular, the washing liquid at least has cleaners added to it. The effect of these cleaners is, however, once again dependent on the temperature, and, for example, the cleaners may saponify if the temperature is too low, with a corresponding deterioration of the cleaning result. Effects such as these can be effectively avoided by the described method and the proposed dishwashing machine.

[0028]By way of example, at least one program step in the described two-tank or multiple-tank dishwashing machine may comprise a circulation step, in which case the controller may be designed such that the dishwashing liquid being circulated is heated at least until the predetermined intended temperature is reached in the washing tank. During this circulation mode, it has been found to be particularly advantageous to detect the start temperature after a predetermined start delay rather than immediately at the start of the circulation step. The start temperature is preferably measured after a start delay of 5 to 60 seconds, in particular between 10 and 20 seconds. This advantageously makes it possible for the dishwashing liquid to be thoroughly mixed first of all in the washing tank in which, for example, there may initially be a temperature gradient from top to bottom, in order to result in an average temperature. In addition, the temperature of the items to be cleaned can be matched to the tank water temperature within the start delay, which means, overall, that the start delay makes it possible to measure an equilibrium temperature instead of a local non-equilibrium temperature. This greatly improves the method and the accuracy.

Problems solved by technology

In many cases, the result of a method such as this is unsatisfactory, however.

If this preset time is inappropriate, then, for example, heating power may be wasted thus in turn lengthening the washing cycle or, on the other hand and in the worst case, regular temperature monitoring can be started shortly after the start of the circulation step which, in the final analysis, represents nothing more than temperature monitoring from the start of this circulation step.

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