Dishwasher, method and control system for handling clogging condition

Abstract

A method for handling a clogging condition in a dishwasher may include detecting the clogging condition; upon detecting the clogging condition, interrupting a wash cycle of the dishwasher and executing a remedial operation to remove the clogging condition. The remedial operation may include executing a drain operation for a predetermined drain time during which a drain pump may be continuously or intermittently operated to drain water from a sump of the dishwasher; following the drain operation, executing a fill operation for a predetermined fill time during which a fill valve may be continuously or intermittently activated to add water to the dishwasher; and following the fill operation, executing a circulation operation during which a circulation pump may be continuously or intermittently operated to remove the clogging condition. A dishwasher and a control system for handling a clogging condition are also provided.

Claims

1. A method for handling a clogging condition in a dishwasher, the method comprising: detecting the clogging condition; upon detecting the clogging condition, interrupting a wash cycle of the dishwasher and executing a remedial operation to remove the clogging condition; wherein the remedial operation comprises: executing a drain operation for a predetermined drain time during which a drain pump is continuously or intermittently operated to drain water from a sump of the dishwasher; following the drain operation, executing a fill operation for a predetermined fill time during which a fill valve is continuously or intermittently activated to add water to the dishwasher; following the fill operation, executing a circulation operation during which a circulation pump is continuously or intermittently operated to remove the clogging condition; determining if the current position of the wash cycle is a predefined allowed position upon detection of the clogging condition; and interrupting the wash cycle and executing the remedial operation if the current position of the wash cycle is a predefined allowed position.

2. The method according to claim 1, wherein the clogging condition is a clogging condition of a filter in the dishwasher.

3. The method according to claim 1, wherein the fill time is based on historical data and/or a nominal value.

4. The method according to claim 1, wherein the circulation pump is operated according to a predefined circulation pattern and for a predefined circulation time during the circulation operation.

5. The method according to claim 4, wherein the circulation time is increased each time the circulation operation is executed during the wash cycle.

6. The method according to claim 1, further comprising limiting the number of executed remedial operations during the wash cycle.

7. The method according to claim 1, further comprising limiting the number of executed remedial operations during at least one wash segment of the wash cycle.

8. The method according to claim 1, wherein the method further comprises: determining a current position of the wash cycle being executed upon detecting the clogging condition; and resuming operation of the dishwasher based on the current position upon completion of the remedial operation.

9. The method according to claim 8, wherein the step of determining a current position of the wash cycle being executed comprises a step of registering a water temperature.

10. The method according to claim 9, wherein the step of resuming operation of the dishwasher based on the current position comprises resuming operation of the dishwasher from the water temperature.

11. The method according to claim 1, wherein the detection of the clogging condition is made continuously throughout the wash cycle.

12. The method according to claim 1, wherein the fill valve is continuously or intermittently activated to add water to a tub of the dishwasher during the fill operation.

13. A dishwasher configured to handle a clogging condition, the dishwasher comprising a control system configured to carry out the method according to claim 1.

14. A control system for handling a clogging condition in a dishwasher, the control system comprising a data processing device and a memory having a computer program stored thereon, the computer program comprising program code which, when executed by the data processing device, causes the data processing device to perform the steps of: detecting the clogging condition; upon detecting the clogging condition, interrupting a wash cycle of the dishwasher and executing a remedial operation to remove the clogging condition; wherein the remedial operation comprises: executing a drain operation for a predetermined drain time during which a drain pump is continuously or intermittently operated to drain water from a sump of the dishwasher; following the drain operation, executing a fill operation for a predetermined fill time during which a fill valve is continuously or intermittently activated to add water to the dishwasher; following the fill operation, executing a circulation operation during which a circulation pump is continuously or intermittently operated to remove the clogging condition; determining if the current position of the wash cycle is a predefined allowed position upon detection of the clogging condition; and interrupting the wash cycle and executing the remedial operation if the current position of the wash cycle is a predefined allowed position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details, advantages and aspects of the present disclosure will become apparent from the following embodiments taken in conjunction with the drawings, wherein:

(2) FIG. 1: schematically represents a perspective view of a dishwasher; and

(3) FIG. 2: schematically represents a cross sectional side view of the dishwasher.

DETAILED DESCRIPTION

(4) In the following, a method for handling a clogging condition in a dishwasher in which a remedial operation comprising a drain operation, a fill operation and a circulation operation is executed, a dishwasher configured to handle a clogging condition, and a control system for handling a clogging condition in a dishwasher, will be described. The same reference numerals will be used to denote the same or similar structural features.

(5) FIG. 1 schematically represents a perspective view of one example of a dishwasher 10 according to the present disclosure. The dishwasher 10 is configured to implement any of the methods according to the present disclosure.

(6) The dishwasher 10 comprises a tub 12 (partly broken away in FIG. 1 to show internal components of the dishwasher 10), a pivotable door 14 and a base portion 16. The tub 12 comprises a plurality of walls 18 for forming an enclosure in which dishes, utensils and other dishware may be placed for washing. The dishwasher 10 may also comprise slidable upper and lower racks (not shown) for holding the dishes, utensils and other dishware. Below the tub 12, a sump 20 is provided in which wash water or rinse water is collected, typically under the influence of gravity.

(7) The dishwasher 10 further comprises a circulation pump 22, an upper spray arm 24, an upper circulation conduit 26 for establishing a fluid communication between the circulation pump 22 and the upper spray arm 24, a lower spray arm 28 and a lower circulation conduit (not shown) for establishing a fluid communication between the circulation pump 22 and the lower spray arm 28.

(8) The dishwasher 10 further comprises a drain pump 30 for pumping water in the sump 20 to a drain hose 32. The drain hose 32 may be connected to a typical home drain plumbing system (not shown). FIG. 1 further shows a control system 34 arranged in the base portion 16. The control system 34 is used to control operation of the drain pump 30, a fill valve (not shown) and the circulation pump 22.

(9) FIG. 2 schematically represents a cross sectional side view of the dishwasher 10 in FIG. 1. As can be seen in FIG. 2, the drain pump 30 and the circulation pump 22 of the dishwasher 10 are arranged in immediate vicinity to the sump 20. However, alternative positions of the drain pump 30 and the circulation pump 22 are possible. FIG. 2 further shows the lower circulation conduit 36 that provides the fluid communication between the circulation pump 22 and the lower spray arm 28.

(10) The dishwasher 10 comprises a fill valve 38 for being activated (e.g. opened or partly opened) in order to add water 40 from an inlet hose 42 into the dishwasher 10 or deactivated to close communication between the inlet hose 42 and the interior of the dishwasher 10. The inlet hose 42 may be connected to a water supply (not shown).

(11) A filter 44 is provided between the tub 12 and the sump 20 to filter soils 46 from the water 40. The dishwasher 10 further comprises a detection device 48, here implemented as a pressure sensor, in order to detect a clogging condition of the filter 44. The detection device 48 is optional and parameters of the circulation pump 22 and or the drain pump 30 may alternatively be used to detect a clogging condition of the filter 44. The dishwasher 10 may also be configured to detect a clogging condition of components other than the filter 44.

(12) In FIG. 2, the fill valve 38 is arranged to add water 40 into the tub 12, i.e. upstream of the filter 44. However, the fill valve 38 may alternatively be arranged to add water 40 directly into the sump 20, i.e. downstream of the filter 44. Furthermore, the detection device 48 is arranged in the sump 20 in FIG. 2 but the detection device 48 may alternatively be arranged, for example, in the tub 12.

(13) The dishwasher 10 in FIG. 2 further comprises a circulation pump signal line 50 for signal communication between the control system 34 and the circulation pump 22, a drain pump signal line 52 for signal communication between the control system 34 and the drain pump 30, a fill valve signal line 54 for signal communication between the control system 34 and the fill valve 38 and a detection device signal line 56 for signal communication between the control system 34 and the detection device 48.

(14) As illustrated in FIG. 2, the sump 20, the detection device 48, the drain pump 30, the circulation pump 22 and the control system 34 are provided in the base portion 16 of the dishwasher 10. However, an alternative positioning within the dishwasher 10 of one or more of these components is possible.

(15) The dishwasher 10 may optionally comprise a chimney (not shown) to establish a fluid communication between the sump 20 and a height within the tub 12 close to an alarm level that indicates the occurrence a flooding condition of the dishwasher 10. The chimney may also be provided with a filter.

(16) The control system 34 comprises a data processing device (not shown) and a memory (not shown). The memory has a computer program stored thereon having program code which, when executed by the data processing device, causes the data processing device to perform the steps of any of the methods according to the present disclosure.

(17) During a typical wash cycle, the dishwasher 10 may provide water 40 through the circulation pump 22 to the upper and/or lower spray arms 24, 28 to cause water 40 to spray into the tub 12. The water 40 that is sprayed into the tub 12 falls, for example due to gravity, to the sump 20 and interacts with the filter 44. As the circulation pump 22 pumps the water 40, the water 40 may partially or fully pass through the filter 44 for soil collection. Although FIG. 2 only shows one filter 44, the dishwasher 10 may alternatively comprise several filters 44.

(18) During the wash cycle, soils 46 (or other particles) might can become stuck on the filter 44 causing a clogging condition that prevents or slows water 40 from passing through the filter 44 to the circulation pump 22. A lower water level within the sump 20 might cause the circulation pump 22 to suck in air, which may make the discharge flow of the circulation pump 22 become intermittent or even to stop as the circulation pump 22 loses its prime. This may damage the circulation pump 22.

(19) A clogging condition may be detected in various ways. In one example, a clogging condition of the filter 44 can be detected when the signals from the detection device 48 indicates that the water level in the sump 20 deviates from an expected value at a particular position of the wash cycle. Parameters of the drain pump 30 and/or the circulation pump 22 may also be used to detect a clogging condition, such as a clogging condition of the filter 44. A turbidity sensor (not shown) may also be provided in the dishwasher 10 to detect a clogging condition. The dishwasher 10 may be configured to continuously detect a clogging condition, e.g. a clogging condition of the filter 44, throughout the entire wash cycle.

(20) Once a clogging condition has been detected, the method according to the present disclosure provides for an interruption of the wash cycle of the dishwasher 10 and an execution of a remedial operation to remove the clogging condition of the filter 44. The wash cycle may be interrupted immediately upon detection of the clogging condition. Alternatively, the wash cycle may wait for a predefined allowed position of the wash cycle before executing the remedial operation.

(21) The remedial operation comprises a first step of executing a drain operation for a predefined drain time. During the drain operation, the drain pump 30 is driven continuously, for example at low speed, or intermittently, to pump water 40 from out from the sump 20 to the drain hose 32.

(22) Once the drain operation is completed, i.e. when the drain time has lapsed, it is assumed that the sump 20 is empty or substantially empty and the remedial operation switches from the drain operation to a fill operation. In the fill operation, the fill valve 38 is opened continuously or intermittently to let fresh water 40 from the inlet hose 42 enter into the interior of the dishwasher 10. In the example of FIG. 2, the water 40 enters directly into the tub 12. The fill operation is executed during a predefined fill time. As mentioned above, the fill time can be predefined based on historical data and/or based on a nominal value.

(23) Once the fill operation is completed, i.e. when the fill time has lapsed, it is assumed that the sump 20 contains a sufficient amount of water 40 to saturate the circulation pump 22 and the remedial operation switches from the drain operation to a circulation operation. In the circulation operation, the circulation pump 22 is driven (e.g. continuously and/or with pulses) to remove the clogging condition. Various modes of operations of the circulation pump 22 for removing clogging conditions are known. For example, the circulation pump 22 may be driven to spray water 40 onto the filter 44 via the lower spray arm 28 only.

(24) However, in contrast to prior art circulation operations, the circulation pump 22 may be operated in the circulation operation for a predefined circulation time and/or with a predefined circulation pattern. In other words, the operation of the circulation pump 22 can be defined in advance such that the circulation operation is executed without using any sensor inputs, e.g. from the detection device 48.

(25) The circulation time for the circulation operation may be increased each time the circulation operation is executed during the same wash cycle. If a clogging condition is detected and remedial operation (including a circulation operation) is executed a second time, this could be an indication that the previous circulation operation was not fully successful. For this reason, the circulation time can be increased each time the circulation operation is executed.

(26) Throughout the wash cycle, or throughout one or more wash segments of the wash cycle, the number of executed remedial operations can be limited. This may for example be realized by using a remedial operation counter. Thereby, it can be avoided that the wash cycle is stopped in an infinite loop due to misleading clogged sensors.

(27) Once a remedial operation has been executed, the wash cycle may be resumed based on the current position where the wash cycle was interrupted to execute the remedial operation. The dishwasher 10 may comprise a temperature sensor (not shown) to continuously register a water temperature, e.g. the temperature of the water 40 in the sump 20. Instead of resuming the wash cycle based on a target temperature of the current position where the wash cycle was interrupted, the actual temperature of the to water 40 can be used instead. This improves the cleaning performance of the dishwasher 10.

(28) While the present disclosure has been described with reference to exemplary embodiments, it will be appreciated that the present invention is not limited to what has been described above. For example, it will be appreciated that the dimensions of the parts may be varied as needed. Accordingly, it is intended that the present invention may be limited only by the scope of the claims appended hereto.