Cleaning and liquid contact with solids – Processes – Combined
Reexamination Certificate
2001-03-12
2003-09-23
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
Combined
C134S025200, C134S0570DL
Reexamination Certificate
active
06623565
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention lies in the field of household appliances. The invention relates to a method for operating a household dishwasher and a household dishwasher for carrying out the method. The dishwasher includes a washing container filled through a fresh-water feedline provided with an inlet valve, a circulating pump connected on the suction side to the washing container and on the delivery side to at least one spray device, an emptying pump connected on the suction side to the washing container and on the delivery side to an outflow line, and a program control unit having control devices for controlling the pumps.
German Published, Non-Prosecuted Patent Application DE 20 13 716 A1 discloses a method and a household dishwasher. In the dishwasher, the delivery line of the circulating pump has in it a pressure measuring device that, while the circulating pump is in operation, opens the inlet valve and keeps it open as soon and as long as the pressure in the delivery line of the circulating pump falls below an intended pressure. The function serves for cleaning a sieve configuration that proceeds the circulating pump and, in the event of a deposit of dirt, causes a pressure drop in the delivery line of the circulating pump. As a result of the subsequent opening of the inlet valve, fresh water is delivered up to an upper predetermined level and, by operating the emptying pump, is then pumped away again down to a lower predetermined level. Should the pressure in the delivery line of the circulating pump still be lower than the predetermined pressure, the operation is repeated. The sieve configuration is flushed free as a result of the interaction.
German Published, Non-Prosecuted Patent Application DE 26 46 383 A1 discloses a further method and household dishwasher. The dishwasher likewise has in the delivery line of the circulating pump a pressure measuring device that, while the circulating pump is in operation, opens the inlet valve and keeps it open as soon and as long as the pressure in the delivery line of the circulating pump falls below an intended pressure. Thus, it matches the washing liquid quantity to the dirt quantity absorbed, that is to say, when the washing liquid becomes more viscous due to the absorption of dirt, the feed pressure of the circulating pump decreases, thus leading to further filling with liquid, i.e., dilution of the washing liquid. When a maximum level is reached, without the feed pressure of the circulating pump having reached the predetermined pressure, liquid is pumped away down to a minimum level by the emptying pump and the inlet valve is then kept open until the feed pressure of the circulating pump has reached the predetermined pressure.
Prior art methods and household dishwashers also include a prescribed partial exchange of the washing liquid in specific subprogram steps or between subprogram steps. Such a dishwasher can be found, for example, in German Published, Non-Prosecuted Patent Application DE 42 43 868 A1. That dishwasher unnecessary consumes water and energy due to the predetermined maximum and minimum levels because different subprogram steps are operated with different liquid quantities and the partial-exchange liquid quantity cannot be matched to these different liquid quantities.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method for operating a household dishwasher and household dishwasher for carrying out the method that overcomes the hereinafore-mentioned disadvantages of the heretofore-known methods and devices of this general type and that provides a possibility for carrying out a partial exchange of the washing liquid in a simple way without unnecessary water and energy consumption.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for operating a household dishwasher, including the steps of filling a washing container through a fresh-water feedline having an inlet valve, connecting a variable-speed circulating pump to the washing container on a suction side of the circulating pump and to at least one spray device on a delivery side of the circulating pump, connecting an emptying pump to the washing container on the suction side of the emptying pump and to an outflow line on a delivery side of the emptying pump, providing a program control unit having control devices for controlling the circulating and emptying pumps, operating both of the circulating and emptying pumps during a partial exchange of the washing liquid, and determining a washing liquid quantity to be pumped away and thereafter to be introduced again by a rotational speed of the circulating pump.
A partial exchange of the washing liquid is simply performed without unnecessary water and energy consumption by operating both pumps during a partial exchange of the washing liquid, and by determining the washing liquid quantity to be pumped away and thereafter to be introduced again by the rotational speed of the circulating pump, which has a variable rotational speed.
The method according to the invention is performed by providing a circulating pump with a rotational speed sensor and a variable rotational speed, and opening and/or closing the inlet valve and/or placing the emptying pump into operation or switching it off while the circulating pump is in operation based on the signals from the rotational speed sensor. During a partial exchange of the washing liquid, both pumps are operated. The washing liquid quantity to be pumped away and/or to be introduced is determined by the rotational speed of the circulating pump.
A low rotational speed of the circulating pump causes a high liquid level to prevail, that is to say, a large liquid quantity to accumulate, in the suction space of the washing container, also referred to as the pump bulb or bowl. A high rotational speed of the circulating pump correspondingly causes a low liquid level to prevail, that is to say, a small liquid quantity to accumulate, in the pump bowl. Because that partial quantity of the liquid quantity accumulated in the pump bowl that is to be pumped away and then filled up again during a partial exchange of the washing liquid is extracted and supplied again, in each subprogram step not only the overall liquid quantity can be set by the circulating pump of variable rotational speed and matched to the respective liquid quantity used in the individual subprogram steps, but also the partial-exchange quantity. During the emptying of the partial quantity, the liquid quantity falls. The fall causes the inlet valve to open and the emptying pump to be switched off so that new liquid can flow in until the circulating pump rotates again, that is to say, air is no longer drawn in. The rotational speed sensor signals the condition and the inlet valve is closed again. Thus, a liquid quantity matched to the subprogram step is extracted and supplied again only according to the rotational speed of the circulating pump. In a method for operating a household dishwasher and in a household dishwasher for carrying out the method according to the invention a possibility of carrying out a part exchange of the washing liquid without unnecessary water and energy consumption is afforded in a simple way.
In accordance with a mode of the invention, during a partial exchange of the washing liquid, the emptying pump, based on the signals from the rotational speed sensor, operated in addition to the circulating pump which is itself in operation, is switched off and the inlet valve is opened. And, the inlet valve is closed again based on the signals from the rotational speed sensor. During the emptying of the partial quantity, the liquid quantity falls until the circulating pump no longer rotates, that is to say, until air is also drawn in. The fall causes a variation in the rotational speed of the circulating pump that is signaled by the rotational speed sensor and that leads to the opening of the inlet valve and to the switching off of the emptying pump so that new liquid can fl
Hering Reinhard
Reiter Bruno
Rosenbauer Michael
BSH Bosch und Siemens Hausgeräte GmbH
Chaudhry Saeed
Greenberg Laurence A.
Gulakowski Randy
Maybeck Gregory L.
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