DE29520466U1 - Water-bearing, program-controlled household appliance - Google Patents

Description

Bosch-Siemens Household Appliances* ^# 6rfifcii ··· *§l669>*küabhen, 10.11.1995

Hochstrasse 17

ZRP95P310 Ws/hü

Water-conducting, program-controlled household appliance

The invention relates to a water-conducting, program-controlled household appliance with a water supply system, consisting of an inlet hose connected to a water tap, with a safety device consisting of two electrovalves arranged between the water tap and the inlet hose, whereby the electrovalves are controlled separately by the program control device and are operated alternately during at least one program section without water supply.

Water-conducting, program-controlled household appliances, e.g. household dishwashers or washing machines with a safety device between the tap of the public fresh water network and the inlet hose of the household appliance, which stops the water supply to the household appliance if a leak is detected in the inlet hose, have been known for a long time. These safety devices have the disadvantage that a fault in this safety device due to wear or jamming

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zen of a valve cannot be detected and the household appliance then continues to operate without the safety function.

From DE-OS 44 02 977' a water-carrying, program-controlled household appliance of the type mentioned at the beginning is known, with which a check of the safety device takes place in that the electromagnetic valves are controlled separately by the program control device and are operated alternately without water supply during at least one program section. For this purpose, a separate container is provided in the household appliance according to DE-OS 44 02 975, which is connected during the check via a branch of the water supply system switched with an additional valve and in which a level sensor is arranged which, when water flows into the separate container, indicates a malfunction of one of the electromagnetic valves of the safety device, interrupts the power supply to the household appliance and/or switches on a warning lamp. The arrangement of an additional valve, an additional container with a level sensor (e.g. a float with a switch) is complex and requires additional control effort for the switching of the additional valve.

The invention is therefore based on the object of creating a water-conducting, program-controlled household appliance in a simple manner in which the safety device can be checked cost-effectively.

This object is achieved according to the invention in that a pressure sensor is arranged in the water supply system, the switch of which in the event that the pressure sensor in the alternating

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If the solenoid valves, which are controlled separately by the program control unit, detect water inflow during a program section without water inflow, the program control unit switches off.

The use of a pressure sensor that switches off the program control device in the event of a fault and that can be arranged anywhere in the water supply system is significantly more cost-effective than the arrangement according to the state of the art described above. The invention has thus succeeded in creating a water-carrying, program-controlled household appliance in a simple manner in which the safety device can be checked inexpensively.

According to an advantageous embodiment of the invention, the separately controlled solenoid valves are operated alternately during a "drying" sub-program step and emptying does not take place during the "drying" sub-program step. As a result, in the event of an error in the "drying" sub-program step, in which there is usually no water in a treatment room, e.g. a household dishwasher, water is introduced so that the user is made aware of the error without additional measures, such as the installation of a warning lamp, in the previously discussed state of the art. With this measure, further cost savings are possible when checking the safety device.

The invention is explained below with reference to the embodiments shown in the drawing.

Fig. 1 is a circuit diagram of the arrangement according to the invention,

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Fig. 2 is a flow chart for a preferred embodiment of the invention and

Fig. 3 is a flow chart for a further advantageous embodiment of the invention.

The invention is explained using the embodiments used in a household dishwasher that are not explained in more detail. The household dishwasher according to the embodiments is connected to the public water supply network with a water tap 1 that is shown schematically in Figure 1 and an inlet hose 2. The household dishwasher has a safety device 3 that is arranged between the water tap 1 and the inlet hose 2 and consists of two solenoid valves 5, 6 arranged one behind the other in the direction of water flow (indicated by arrows 4). These solenoid valves 5, 6 are controlled separately by a program control device 7 via associated switches 8, 9 of the program control device 7. A float switch 11 of a float arranged, for example, in a leakage water tray is also arranged in the power supply line, which interrupts the power supply line if leakage water occurs in the leakage water tray.

According to the invention, a pressure sensor is arranged in the water supply system, which can switch off the program control device 7. The switch 10 of the pressure sensor is arranged in the power supply line. The circuit diagram described above and shown in Figure 1 can be used for both embodiments shown below.

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In Fig. 2, a valve flow diagram is shown for the preferred embodiment of the invention, whereby the alternating operation of the solenoid valves 5, 6 according to the invention takes place in a partial program "rinse", after the end of the usual program water supply and in a subsequent partial program section "drying". In the flow diagram in Fig. 2, the relevant time period of the partial program section "rinse" is designated by K and the relevant time period of the partial program "drying" by T, as well as a further time period following the partial program step "drying", in which the filled items to be washed are completely dried over a standing time, is designated by St. As can be seen from Fig. 2, after filling has been completed, this time being indicated by a dot-dash vertical line, in the partial program step "rinse" K, the first solenoid valve 5 is closed, whereas the second solenoid valve 6 is opened. In the "drying" sub-program step, the first solenoid valve 5 is open without interruption for the entire duration and the second solenoid valve 6 is closed for the entire duration. During the idle time St, both valves are closed. S indicates the parts of the rinsing program that lie before the "rinse" sub-program section in general and the valve movements in these sub-program steps.

The first solenoid valve 5 is checked in the last part of the time period of the partial program step "Rinse" K, in which it is permanently closed. If the pressure sensor in the water supply system detects a pressure in this phase, the solenoid valve is

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solenoid valve 5 is not clearly closed and switch 10 of the pressure sensor interrupts the supply line to the program control unit 7. If no error occurs during this test, the second solenoid valve 6 is then checked by keeping the first solenoid valve 5 constantly open and the solenoid valve 6 constantly closed in the sub-program step "drying". If the pressure sensor detects water pressure in the water supply system during the sub-program step "drying", the solenoid valve 6 is not closed or not completely closed and switch 10 of the pressure sensor switches off the supply line to the program control unit 7.

The interruption of the current washing program of the household dishwasher explained always alerts the user of the household dishwasher to a fault in the safety device 3 of the household dishwasher, so that he can take appropriate measures, which usually means calling customer service.

An even clearer indication of a fault in the safety device 3 of the household dishwasher is generated according to a further advantageous embodiment of the invention with the flow chart shown in Figure 3. The check of both solenoid valves 5, 6 takes place in the "drying" sub-program section T of a running washing program of the household dishwasher, with the first solenoid valve 5 being permanently open and the second solenoid valve 6 being closed in a first time period. If the pressure sensor detects a pressure in the water supply system during this phase

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of the household dishwasher, the second solenoid valve 6 is not closed or not completely closed. The switch 10 of the pressure sensor interrupts the power supply to the program control unit 7. If this fault does not occur, in the following phase the first solenoid valve 5 is closed and the second solenoid valve 6 is opened. If the pressure sensor in the water supply system of the household dishwasher detects water pressure in this phase, the first solenoid valve 5 is not closed or not closed correctly and the switch 10 of the pressure sensor interrupts the power supply to the program control device 7. Since the washing container of the household dishwasher is usually operated without liquid during the "drying" sub-program step and emptying does not take place according to the invention, the user not only notices that there is water in the washing container but also notices in a particularly obvious way that there is a fault in the safety device 3 of the household dishwasher and can take appropriate measures, e.g. call customer service.

Claims (2)

i * —J 1 4S * &idigr;&idigr;&idigr;&idigr;». ZRP95P310 PROTECTION CLAIM 1. Water-carrying, program-controlled household appliance with a water supply system, consisting of an inlet hose connected to a faucet, with a safety device, consisting of two solenoid valves arranged between the faucet and the inlet hose, whereby the solenoid valves are controlled separately by the program control device and are operated alternately during at least one program section without water supply, characterized in that a pressure sensor is arranged in the water supply system, the switch (10) of which switches off the program control device (7) in the event that the pressure sensor detects a water supply during the alternate operation of the solenoid valves (5, 6) controlled separately by the program control device (7) during a program section without water supply. 2. Water-conducting, program-controlled household appliance according to claim 1, characterized in that the separately controlled electromagnetic valves (5, 6) are operated alternately during a "drying" sub-program step and emptying does not take place during the "drying" sub-program step.