EP2052665A1 - Household device with an adjustable fluid distribution device and method for its control - Google Patents

Abstract

The household appliance has a liquid distribution device for adjusting the distribution of liquid within the household appliance. A detection device is provided for detecting a dependent condition of the liquid from the distribution of liquid. The detection device has a liquid level sensor arranged on the suction side of a circulation pump (6). The liquid level sensor measures the liquid level of a container at the ground area. The detection device has two flow sensors (30,32) for liquid flow. An independent claim is included for a method for detecting the function of an adjustable liquid distribution device.

Description

The invention relates to a domestic appliance, in particular a dishwasher, with an adjustable liquid distribution device for adjusting the liquid distribution within the domestic appliance, and a method for controlling the liquid distribution device.

From the EP 0 237 994 B1 and the WO 01/03568 A1 In each case a dishwasher with a switchable distributor valve is known. From the dishwasher sump of the dishwasher is sucked through a circulation pump rinsing liquid and fed through the distribution valve an upper and lower spray arm. In the distribution valve, a movable ball is arranged, which releases by temporal variation of the operation of the circulation pump, a first line to the upper spray arm, a second line to the lower spray arm or in an intermediate position both lines to two spray arms. If the circulation pump is out of operation, the switching element falls into a defined basic state within the distribution valve. The switching of the distribution valve allows the selection of the spray arm to be operated, so that, for example, with little items only one spray arm is operated to save water or the items to be washed is applied from only one spray with high Spülflüssigkeitsmenge.

The object of the invention is to provide a household appliance and to provide for this a method in which the secure reaching a switching position of a liquid distribution device is verifiable.

This object is achieved with the features of claim 1 and 11, respectively.

According to claim 1, the liquid is distributed within the household appliance in a household appliance during operation by an adjustable liquid distribution device. For example, in a dishwasher, the rinsing liquid circulated by a circulating pump is distributed by the liquid distribution device to different spray arms. The liquid distribution device can operate linearly, i. vary the liquid distribution continuously or switch the liquid distribution in stages. For this purpose, the liquid distribution device preferably has at least one adjusting element with which the distribution of the liquid within the device is set. It may happen that the actuator was not properly controlled or the desired position was not reached. As a result, after a switching process in the liquid distribution device, the actual distribution of the liquid may deviate from the desired liquid distribution. To detect such a deviation, a detection device is provided, with which the actual state of the liquid is detected within the household appliance. By detecting the actual state as a measure of the liquid distribution, a comparison with the desired state of the liquid distribution device is made possible. Regardless of the possible cause of the malfunction of the liquid distribution device thus the effect of the malfunction is detected. The liquid distribution or a change of the liquid distribution affects the liquid flow, the liquid level, the pressure of the liquid in different areas or the like.

The liquid distribution device can for example be hydraulically switched by the liquid flow, such as by means of the EP 0 237 994 B1 known ball valve. Or the liquid distribution device is adjusted by a coupled to a motor drive adjustment, such as a rotary valve, a valve disc or similar. The motor drive is, for example, a magnetic switch, an electric motor, a pneumatic or hydraulic device.

If the state of the liquid is detected with a liquid level sensor, then the individual switching states of the liquid distribution device can be detected on the basis of the differences in the liquid level. In doing so, e.g. depending on the switching position different amount of liquid circulated in liquid lines, distributed within the household appliance or the like, so that each sets a different liquid level for each switching position.

The liquid level can be advantageously measured with an analog pressure sensor, with a float switch, a pressure switch, an ultrasonic level gauge or the like. The measurement can be done discretely by detecting different level positions, or continuously, so that the most accurate level determination can be done. The liquid column above the pressure sensor can be detected with a pressure sensor.

In a particularly advantageous embodiment, the liquid level sensor is arranged on the suction side of a circulating pump. Since liquid is constantly present at this point, a liquid level measurement can be carried out independently of the distribution selected. In addition, at the beginning of a rinsing cycle, a washing cycle or the like, a measurement of the amount of liquid filled in the household appliance can be performed. Thus, only one component is required to detect the liquid filling amount of the household appliance and the actual position of the liquid distribution device. This is advantageously carried out in the bottom region of a container of the household appliance. For example, in the dishwasher sump in the washing of a dishwasher, since here the rinsing liquid moves comparatively slowly and an average of the liquid level is particularly easy to measure.

In addition to the level measurement, or alternatively, the condition of the liquid is detected with a liquid flow meter. The liquid measurement can be measured directly by a lever, which is deflected by the fluid pressure, by a measuring wheel or indirectly by a pressure sensor, which responds to the liquid accumulation pressure. For this purpose, one or more flow meters are provided in the line system of the household appliance, wherein at a known flow rate of a circulating pump of the household appliance, the flow rate of the liquid in the individual line sections depends on which switching state the liquid distribution device occupies. Advantageously, at least one flow sensor is arranged in the inlet and / or at least one outlet of the liquid distribution device.

The signal detected by the detection device about the state of the liquid is advantageously sent via a signal line to a control device. The further evaluation of the detection signal then takes place in the control device. Typically, the controller is the programmer control of the home appliance. For example, the washing program control of a dishwasher.

The control device is in turn connected via a control line to the liquid distribution device and / or a circulating pump. Depending on whether the liquid distribution device is switched by a motor drive or e.g. by the timing of the circulation pump, corresponding control signals are provided by the control device.

According to the method of claim 11, the function of an adjustable liquid distribution device of a domestic appliance is detected based on the state of the liquid actually taken after the liquid distribution device has been set.

Advantageously, the instantaneous state of the liquid is compared with a predetermined desired value. Depending on the number of switching states, a plurality of different, predetermined setpoints are advantageously provided, which should each be achieved from the instantaneous state of the liquid when the liquid distribution device is operating correctly. Preferably, each switching state is compared by means of a separate setpoint, so that an unambiguous assignment can take place.

In a particularly advantageous embodiment, the liquid distribution device is switched over an intermediate position again in the selected position when it was detected by a deviation of the current state of the liquid from the target value that the desired position has not been reached. Is e.g. an adjustment of the liquid distribution device jammed for a short time or not close tightly by an impurity in the liquid at an outlet opening, this state is brought about by an intermediate switching, preferably the idle state, and re-driving the desired position.

Preferably, the number of repetitions is limited, wherein when the number is exceeded and further malfunction of the liquid distribution device an error message is issued. Thus, the user of the household appliance is informed that maintenance must be performed. It can be provided that the household appliance continues to operate despite the malfunction.

In a particularly advantageous embodiment, the desired value for a predetermined position of the liquid distribution device is not fixed unchangeable, but is adapted based on other operating parameters of the household appliance. If, for example, more dishwashing liquid is needed in a dishwasher for a wash program than for another wash program, then the predetermined desired value is adapted in accordance with the amount of wash liquid. For example, it changes the liquid level in the bottom area of a container of the household appliance, depending on whether more or less total amount of liquid is used. Therefore, even during operation of the liquid distribution device in different positions, the absolute value of the predetermined setpoint (s) changes.

A normalization of the setpoint or values is advantageously carried out in a defined operating state of the dishwasher. By means of this normalization of the predetermined desired value, for example, a deviation in the filled-in total liquid quantity can be compensated. This is done e.g. in a dishwasher, a correction if more rinse liquid adheres to the items to be washed. Furthermore, operational wear phenomena, e.g. the circulation pump can be considered without much effort.

With reference to figures, embodiments of the invention will be explained.

• Fig. 1 eine schematische Darstellung eines Spülflüssigkeitskreislaufs in einer Geschirrspülmaschine und
• Fig. 2 verschiedene Spülflüssigkeitsniveaus im Spülmaschinensumpf bei unterschiedlichen Stellungen eines Ballswitch.

Show it:

• Fig. 1 a schematic representation of a Spülflüssigkeitskreislaufs in a dishwasher and
• Fig. 2 different rinsing fluid levels in the dishwasher sump at different positions of a ball switch.

Fig. 1 shows a schematic representation of the Spülflüssigkeitskreislaufs in a dishwasher. In a washing compartment 1 of the dishwasher, an upper spray arm 2, a lower spray arm 3 and an upper and lower dish rack 4 are arranged. By means of the spray arms 2, 3, the items to be washed stored in the dish racks 4 are treated with rinsing liquid, which then collects in the rinsing space 1 or rinsing container in the rinsing machine sump 5. By a circulation pump 6, the rinsing liquid is sucked from the dishwasher sump 5 and conveyed through a connecting line 7 to a switching valve 8 and ball switch. In the switching valve 8, the rinsing liquid from the circulating pump 6 is selectively passed through a first line 9 to the upper spray arm 2, through a second line 10 to the lower spray arm 3, 'or both the lower and upper spray arm 2, 3. A bypass line 11 leads from the valve body to the suction side of the circulation pump. 6

Within the valve body of the switching valve 8, a flow guide 18 is arranged, which deflects the liquid flow coming from the circulating pump 6 in a streamlined manner to the first and / or second line 9, 10. Furthermore, a ball 14 is movably mounted within the valve body, which in Fig. 1 can assume switching positions marked I, II and III. In the switching position I, the bypass line 11, in the switching position II, the first line 9 and in position III, the second line 10 is closed. In the position I, the ball 14 is held by the pressure difference between the inflowing into the switching valve 8 rinsing liquid and the inlet-side suction before the circulation pump 6. In addition, a flow around the ball 14 in the position I is prevented by the flow guide 18.

When the circulation pump 6 is not in operation, the ball 14 falls regardless of their previous position I, II or III back to a basic position, not shown, which due to the oblique course of the guide for the ball 14 within the switching valve 8 slightly below and left offset to position II (in the plan view of Fig. 1 ). The switching takes place in a similar way as in the EP 0 237 994 B1 or WO 01/03568 A1 , By starting the circulating pump 6, the ball 14 is first brought into the position II, where it closes the first line 9. In this case, a defined amount of leakage flows into the line 9. As soon as the circulation pump is turned off for a short time, the liquid from the first line 9 pushes the ball 14 in the direction of the ball III. If the circulating pump 6 is turned on again at this time, the ball 14 is held there and the line 10 is closed. If the circulation pump 6 at switched off the position III of the ball, it moves in the direction of position II or home position. On the way of the ball from position II to III or from position III to II or the basic position, the ball can be kept in the position I by switching on the circulation pump. In this case, both spray arms 2, 3 are supplied with rinsing liquid.

The liquid level of the rinsing liquid in the dishwasher sump 5 depends on whether the circulating pump 6 is in operation and which position the ball 14 occupies. Once the fresh water supply has been turned off and the circulation pump 6 is out of operation, the rinsing liquid from the lines 9 and 10 and the spray arms 2, 3 back or out and collects in the dishwasher sump 5. At this time, a maximum Spülflüssigkeitsniveau in the dishwasher sump 5 a as it is in Fig. 2 is marked with the level A.

If the ball assumes the position II after a switching operation, then only the lower spray arm 3 is supplied with rinsing liquid. Here, the second line 10 and the lower spray arm 3 are filled with rinsing liquid and a certain amount of rinsing liquid, which has been sprayed from the spray arm 3, has not yet run back into the dishwasher sump. Compared to the liquid level A, this additionally required amount of liquid causes a lowering of the liquid level A to level B. Was the ball 14 brought by a switching operation by means of the circulation pump 6 in the position III, the upper spray arm 2 is acted upon with rinsing liquid, wherein the first line and the spray arm 2 are filled with liquid. A certain amount of liquid has also not yet returned to the dishwasher sump 5, because this example adheres to items to be washed and on the walls of the washing and still run back from there. Due to the larger volume of the first line 9 relative to the second line 10 and the distribution of the rinsing liquid on the items to be washed in the upper and lower crockery basket 4, the liquid level C in this Condition against the liquid level B lowered even further, as in Fig. 2 shown.

Finally, when the ball 14 has been switched to the position I, both the upper and the lower spray arms 2, 3 are supplied with rinsing liquid. Both spray arms 2, 3 and the lines 9 and 10 are filled with rinsing liquid, and the rinsing liquid quantity distributed in the rinsing chamber 1 is the largest here. Therefore, in this switching position, the liquid level D is even lower. Thus, each position of the ball valve, a fluid level can be assigned, wherein in summary in the basic position of the ball 14, the level A is reached, in the position II, the level B, in the position III, the level C and in the position I, the level D.

For monitoring the liquid level, a pressure sensor 21 or ultrasonic level meter is arranged at the bottom of the dishwasher sump 5, which detects the average level of the rinsing liquid in the dishwasher sump 5. The corresponding signal is transmitted from the pressure sensor 21 via a signal line 22 to a control unit 20 of the dishwasher. The control unit 20 compares the signal from the pressure sensor 21 with a desired value and causes the circulating pump 6 in a deviation of the actual value of the setpoint to a renewed activation of the desired position of the ball 14 in the changeover valve 8. For this purpose, from the control unit 20, a control signal via the control line 25th sent to the drive unit 24 of the circulation pump 6.

As described above, for each of the positions I, II, III and the home position, there is a separate liquid level A, B, C and D, and correspondingly a separate setpoint for the respective position of the ball 14 in the changeover valve 8. At the beginning of a rinse cycle while advantageously set the desired value by normalization. For this purpose, the fresh water required for the wash program is introduced and circulated for a short time. After switching off the circulation pump 6 and a short waiting time Then, the target value for the base level A is set at which a certain amount of flushing liquid adheres to the dishes or was collected in this. With respect to this normalized base level A, now the levels B, C and D are set as relative setpoints. By means of this standardization, for example, fluctuations in the supply of fresh water or differences in the rinsing liquid adhering to the items to be washed are compensated.

In addition, it can be provided that the setpoints, which are compared with the actual values in the various positions, also depend on the selected speed of the circulating pump 6, since the amount of liquid in the lines 9, 10 and the spray arms 2, 3 and the momentarily in the washing compartment 1 distributed rinsing liquid depend on the liquid pressure and the pump speed.

If a deviation between the measured level and one of the desired positions I, II, III of the ball 14 is detected, the position of the ball 14 is attempted to be reached again by triggering the circulation pump 6. If e.g. after five times repeating this switching attempt, the desired position has not yet been reached or the corresponding liquid level is not detected, then an error message is displayed for the operator on the control panel and stopped the rinsing or continued with the malposition.

Alternatively, in the case of a deviation between the actual and the desired value of the fluid level, for example, the desired switching position is attempted three times by means of activation of the circulating pump 6. If this was not achieved after the third shift attempt, a new normalization of the fluid levels is carried out, for example, by switching off the circulation pump 6 and carrying out a normalization of the fluid level A when the circulation pump 6 is turned off. With the new standardized setpoint values, the desired switching position is then activated again and the setpoint value and the actual value are compared again. If, for example, the position is not reached again after three switching attempts, so also an error message is issued as above.

In a second embodiment, instead of or in addition to the pressure sensor 21 (or ultrasonic level gauge), flow sensors 30, 32 or pressure sensors are provided. In this case, the first flow sensor 30 is arranged on the first line 9 and the second flow sensor 32 on the second line 10. The flow meter 30, 32 have a driver 31 which projects into the line 9 and 10 and is actuated by the liquid flow. Thus, the flow of the liquid is detected by means of the driver 31 and it can be determined whether and through which of the lines 9, 10 rinsing liquid flows. In the basic position, i. when the circulating pump 6 is switched off, none of the flow sensors 30, 32 responds. If the ball 14 is in position II, then only the flow sensor 32 detects a signal which is passed to the control unit 20 via a signal line 33. In position III, only the flow sensor 30 detects a signal which is sent to the control unit 20 via a signal line 34. In position I, both the first and second flow sensors 30, 32 detect a signal.

In the control unit, a malposition of the switching valve 8 is detected by comparing the signals received from the flow sensors 30, 32 and the signals to be expected at the desired position. In case of misalignment, e.g. a renewed switching of the switching valve 8 by means of the circulation pump 6 is made, as described above to a detected deviation on the basis of the measured with the pressure sensor 21 liquid level.

If a pressure sensor is used instead of the flow sensors 30, 31, a pressure change can be detected on account of the dynamic pressure arising in the lines 9, 10, and thus also whether the lines 9, 10 are flushed with flushing liquid. A malposition of the switching valve 8 can then accordingly, as described for the flow sensors 30, 32 are detected.

LIST OF REFERENCE NUMBERS

1:

Wash cabinet

2:

upper spray arm

3:

lower spray arm

4:

dish rack

5:

Dishwasher swamp

6:

circulating pump

7:

connecting line

8th:

switching valve

9:

first line

10:

second line

11:

Bypass line

14:

Bullet

18:

flow guide

20:

control unit

21:

pressure sensor

22:

signal line

24:

drive unit

25:

control line

30:

first flow sensor

31:

takeaway

32:

second flow sensor

33:

signal line

34:

signal line

Claims (16)

Household appliance, in particular a dishwasher, with an adjustable liquid distribution device for adjusting the liquid distribution within the domestic appliance,
marked by
at least one detection device (20; 21, 30, 32) for detecting a liquid-dependent state (A - D) of the liquid. Domestic appliance according to claim 1, characterized in that the detection device (20; 21) comprises a liquid level sensor (21). Domestic appliance according to claim 2, characterized in that the liquid level sensor (21) on the suction side of a circulating pump (6) is arranged. Domestic appliance according to claim 2 or 3, characterized in that the liquid level sensor (21) measures the liquid level (A - D) in the bottom region (5) of a container. Domestic appliance according to one of the preceding claims, characterized in that the detection device (20; 30, 32) comprises a sensor (30, 32) for the liquid flow, preferably a flow sensor (30, 32) in an inlet (7) and / or at least one outlet (9, 10) of the liquid distribution device (8) is arranged. Domestic appliance according to one of the preceding claims, characterized by a control device (20) which is connected via a signal line (22, 33, 34) to a sensor (21, 30, 32) of the detection device (20, 21, 30, 32). Domestic appliance according to claim 6, characterized in that the control device (20; 21, 30, 32) is connected via a control line (25) to the liquid distribution device (8) and / or a circulating pump (6). Domestic appliance according to one of the preceding claims, characterized in that the adjustable liquid distribution device (8) has at least two outlets and a switching element (14) for releasing or closing the liquid flow through the outlets. Domestic appliance according to one of the preceding claims, characterized in that the liquid distribution device (8) supplies the liquid adjustably to a first and / or second liquid spraying device (2, 3). Method for detecting the function of an adjustable liquid distribution device (8) of a domestic appliance, wherein the instantaneous setting of the liquid distribution device (8) is detected based on the state of the liquid, preferably the detected state (A - D) of the liquid being a liquid flow and / or a liquid level is. Method according to Claim 10, in which the instantaneous state (A - D) of the liquid is compared with at least one predetermined desired value, which preferably depends on a selected position (I-III) of the liquid distribution device (8). The method of claim 11, wherein in a deviation between the desired value and the current state (A - D) of the liquid, the liquid distribution device (8) is again switched to the selected position (I - III). The method of claim 12, wherein the step of claim 15 is repeated n times, where n is a predetermined number. Method according to Claim 11, 12 or 13, in which an error message is output if the selected position (I-III) is not reached. Method according to one of claims 11 to 14, wherein the one or more predetermined set values depend on the operating parameters of the household appliance and / or depend on the amount of liquid in the household appliance and / or the selected program. Method according to one of claims 11 to 15, wherein the predetermined set value is determined by normalization in a defined state of the liquid.

Images