TECHNICAL FIELD

The present disclosure relates to a washing appliance comprising a drain conduit and a drain pump configured to drain a liquid container via the drain conduit. The present disclosure further relates to a method of detecting an operational error in a washing appliance, a computer program, a computer-readable medium, and a control arrangement for a washing appliance.

BACKGROUND

Washing appliances are apparatuses capable of washing items. They have been developed as a way to reduce the manual labour spent. Washing appliances include dishwashers and washing machines. A dishwasher is an apparatus for washing items such as dishware and cutlery. A dishwasher comprises a washing chamber where the items are positioned, usually in racks, and dishwashers typically comprise one or more spray arms spraying washing liquid, e.g. a mixture of water and detergent, onto the items to clean them. The washing liquid is collected in a sump at a bottom of the washing chamber. A circulation pump of the dishwasher is fluidly connected to the sump and pumps washing liquid from the sump to the spray arms during a wash cycle. In order to improve the cleaning efficiency and the final cleaning result, the washing liquid is heated to a high temperature, typically between 45 and 75 °C, by one or more heating elements of the dishwasher.

A washing machine is an apparatus for washing items, such as laundry. Washing machines are sometimes referred to as laundry machine, clothes washer, or simply washer. Most often, a washing machine comprises a perforated wash drum arranged in a drum compartment of the washing machine. The drum compartment comprises a sump at a bottom thereof. During operation, the drum compartment is filled with washing liquid, e.g. a mixture of water and detergent, and the wash drum is driven to rotate in the drum compartment. In this manner, the items in the wash drum are cleaned due to the movement of the items inside the drum. In order to improve the washing efficiency and the final washing result, the washing liquid is heated to a high temperature, typically between 30 and 90 °C, by one or more heating elements of the washing machine.

Most often, a washing appliance comprises a drain conduit and a drain pump configured to drain the sump via the drain conduit. Drain conduits of washing appliances are usually installed and connected to a drain by a user or an installer before the first use of the washing l appliance. The sump may for example be drained via the drain conduit at an end of a washing program and/or between washing cycles of a washing program. Moreover, washing appliances comprise a control arrangement configured to control the operation of the washing appliance. The control arrangement may for example control operation of a circulation pump, the drain pump, one or more heating elements, one or more valves, a motor for rotating the wash drum, and the like. The operation of a washing appliance is associated with several operational aspects. Examples are temperature, intensity of operation, duration of operation, load quantity of items, amount of washing liquid, and the like.

A problem associated with washing appliances is that operational errors can occur in the operation of the washing appliance. Operational errors may for example be caused by a wrongly installed drain conduit. Operational errors may lead to several wrong decisions in control logics of the washing appliance with potential subsequent problems such as overheating, increased risk of fire, component damages, flooding, and the like.

Operational errors can be hard to detect but the occurrences thereof could be lowered by providing the washing appliance with advanced control systems and arrangements.

However, such systems and arrangements usually add cost and complexity to the washing appliance, and generally, on today’s consumer market, it is an advantage if products, such as washing appliances, have conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

SUMMARY

It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by a washing appliance comprising a liquid container configured to accommodate a liquid, a liquid level indicator unit configured to provide data indicative of a liquid level in the liquid container, a drain conduit, and a drain pump configured to drain the liquid container via the drain conduit. The washing appliance further comprises a control arrangement configured to operate the drain pump during a first time period, control the drain pump to a standstill during a second time period following the first time period, and monitor a change of the liquid level during the second time period using data from the liquid level indicator unit. As mentioned above, drain conduits of washing appliances are usually installed and connected to a drain by a user or an installer before first use of the washing appliance. A siphon effect can occur in the drain conduit when the drain conduit is filled with liquid causing liquid to be drawn from the liquid container in an unexpected manner also when the drain pump is inactive. A siphon effect in the drain conduit may be caused by the fact that the drain conduit is installed at too low height and/or if the connection of the drain conduit to the drain seals without any free path between the drain conduit and ambient air for pressure equalization.

In some cases, a siphon effect in the drain conduit may be caused by the fact that the drain conduit has become loose from the drain connection. If so, large amounts of liquid may be drained inside/under cabinets and floors/walls. Moreover, a siphon effect in the drain conduit may lead to several wrong decisions in control logics of the washing appliance, with potential subsequent problems such as overheating, increased risk of fire, component damages, flooding, and the like.

Since the control arrangement of the washing appliance according to the present disclosure is configured to monitor the change of the liquid level during the second time period, a washing appliance is provided capable of detecting presence of a siphon effect in the drain conduit in a simple and efficient manner. Furthermore, a washing appliance is provided capable of detecting whether liquid is leaving the liquid container for some other reason, such as for example as a result of a leakage.

Moreover, a washing appliance is provided capable of detecting whether liquid is leaving the liquid container in an unexpected manner while the washing appliance has conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. This because such an operational error can be detected using a simple and low cost liquid level indicator unit.

As a further result thereof, conditions are provided for improving the operational safety of the washing appliance, for example by performing one or more appropriate actions if the monitored change of the liquid level deviates from an expected change of the liquid level.

In this manner, the operational safety of the washing appliance can be improved, and wrong decisions in control logics of the washing appliance can be avoided, thereby also avoiding potential subsequent problems such as overheating, risk of fire, component damages, flooding, and the like. Accordingly, a washing appliance is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the liquid is a washing liquid used in a washing process in the washing appliance. Thereby, a washing appliance is provided capable of detecting whether washing liquid is leaving the liquid container in an unexpected way in a simple and cost-efficient manner.

Optionally, at least part of the drain conduit is routed via a point located higher than the liquid container. Thereby, a washing appliance is provided capable of detecting a siphon effect in the drain conduit in a simple and cost-efficient manner.

Optionally, the control arrangement is configured to monitor the change of the liquid level so as to detect the presence of a siphon effect in the drain conduit. Thereby, a washing appliance is provided capable of detecting a siphon effect in the drain conduit in a simple and cost-efficient manner. As a further result thereof, the operational safety of the washing appliance can be improved, and wrong decisions in control logics of the washing appliance can be avoided, thereby also avoiding potential subsequent problems such as overheating, risk of fire, component damages, flooding, and the like.

Optionally, the washing appliance comprises a circulation pump, and wherein the control arrangement is configured to monitor the change of the liquid level by operating the circulation pump and monitor one or more electrical quantities of the circulation pump. Thereby, a washing appliance is provided in which the circulation pump is utilized as a liquid level indicator unit. In this manner, the need for a separate sensor or arrangement is circumvented for sensing the liquid level in the liquid container. Accordingly, due to these features, a washing appliance is provided having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Optionally, the control arrangement is configured to monitor the change of the liquid level by detecting the liquid level at two or more points in time and comparing the detected liquid levels at the respective two or more points in time. Thereby, a simple and efficient monitoring of the change of the liquid level is provided. Accordingly, due to these features, a washing appliance is provided having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. Optionally, the control arrangement is configured to perform at least one of a corrective measure and a safety measure if the monitored change of the liquid level deviates from an expected change of the liquid level. Thereby, the operational safety of the washing appliance can be improved thereby reducing the risk of problems such as overheating, fire, component damages, flooding, and the like.

Optionally, the washing appliance comprises an output unit, and wherein the control arrangement is configured to output a notification via the output unit if the monitored change of the liquid level deviates from an expected change of the liquid level. Thereby, a washing appliance is provided capable of notifying a user about a detection of an operational error of the washing appliance. In this manner, the operational safety of the washing appliance can be improved by a user performing appropriate actions, and the risk of subsequent problems such as overheating, fire, component damages, flooding, and the like, can thereby be reduced.

Optionally, the control arrangement is configured to perform a corrective measure if the monitored change of the liquid level deviates from an expected change of the liquid level, and wherein the corrective measure comprises at least one of: changing an operational time of a wash cycle of the washing appliance, delaying an operational step of a wash cycle of the washing appliance, and changing an amount of liquid filled into the liquid container.

Thereby, the operational safety of the washing appliance can be improved and the risk of problems such as overheating, fire, component damages, flooding, and the like, can be reduced.

Optionally, the control arrangement is configured to perform an at least partial restriction of further operation of the washing appliance if the monitored change of the liquid level deviates from an expected change of the liquid level. Thereby, the operational safety of the washing appliance can be improved and the risk of problems such as overheating, fire, component damages, flooding, and the like, can be reduced.

According to a second aspect of the invention, the object is achieved by a method of detecting an operational error in a washing appliance, wherein the washing appliance comprises a liquid container configured to accommodate a liquid, a liquid level indicator unit configured to provide data indicative of a liquid level in the liquid container, a drain conduit, and a drain pump configured to drain the liquid container via the drain conduit, and wherein the method comprises the steps of: operating the drain pump during a first time period, controlling the drain pump to a standstill during a second time period following the first time period, and monitoring a change of the liquid level during the second time period using data from the liquid level indicator unit.

Since the method comprises the step of monitoring the change of the liquid level during the second time period, a method is provided capable of detecting presence of a siphon effect in the drain conduit in a simple and efficient manner. Furthermore, a method is provided capable of detecting whether liquid is leaving the liquid container for some other reason, such as for example as a result of a leakage.

Moreover, a method is provided capable of detecting whether liquid is leaving the liquid container in an unexpected manner while the washing appliance has conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. This because such an operational error can be detected using a simple and low cost liquid level indicator unit.

As a further result thereof, conditions are provided for improving the operational safety of the washing appliance, for example by performing one or more appropriate actions if the monitored change of the liquid level deviates from an expected change of the liquid level.

In this manner, the operational safety of the washing appliance can be improved, and wrong decisions in control logics of the washing appliance can be avoided, thereby also avoiding potential subsequent problems such as overheating, risk of fire, component damages, flooding, and the like.

Accordingly, a method is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the step of monitoring the change of the liquid level comprises the step of: monitoring the change of the liquid level so as to detect the presence of a siphon effect in the drain conduit. Thereby, a method is provided capable of detecting a siphon effect in the drain conduit in a simple and cost-efficient manner. As a further result thereof, the operational safety of the washing appliance can be improved, and wrong decisions in control logics of the washing appliance can be avoided, thereby also avoiding potential subsequent problems such as overheating, risk of fire, component damages, flooding, and the like.

Optionally, the washing appliance comprises a circulation pump, and wherein the step of monitoring the change of the liquid level comprises the steps of: activating operation of the circulation pump, and monitoring one or more electrical quantities of the circulation pump.

Thereby, a method is provided in which the circulation pump is utilized as a liquid level indicator unit. In this manner, the need for a separate sensor or arrangement is circumvented for sensing the liquid level in the liquid container. Accordingly, due to these features, the method allows the washing appliance to have conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Optionally, the step of monitoring the change of the liquid level comprises the steps of: detecting the liquid level at two or more points in time, and comparing the liquid levels detected at the two or more points in time.

Thereby, a simple and efficient monitoring of the change of the liquid level is provided. Accordingly, due to these features, the method allows the washing appliance to have conditions and characteristics suitable for being manufactured and assembled in a cost- efficient manner.

Optionally, the method further comprises: performing at least one of a corrective measure and a safety measure if the monitored change of the liquid level deviates from an expected change of the liquid level.

Thereby, the operational safety of the washing appliance can be improved thereby reducing the risk of problems such as overheating, fire, component damages, flooding, and the like.

Optionally, the washing appliance comprises an output unit, and wherein the method comprises the step of: outputting a notification via the output unit if the monitored change of the liquid level deviates from an expected change of the liquid level.

Thereby, a method is provided capable of notifying a user about a detection of an operational error of the washing appliance. In this manner, the operational safety of the washing appliance can be improved by a user performing appropriate actions, and the risk of subsequent problems such as overheating, fire, component damages, flooding, and the like, can thereby be reduced.

Optionally, the method further comprises: performing a corrective measure if the monitored change of the liquid level deviates from an expected change of the liquid level, and wherein the corrective measure comprises at least one of: changing an operational time of a wash cycle of the washing appliance, delaying an operational step of a wash cycle of the washing appliance, and changing an amount of liquid filled into the liquid container.

Thereby, the operational safety of the washing appliance can be improved and the risk of problems such as overheating, fire, component damages, flooding, and the like, can be reduced.

Optionally, the method further comprises: at least partial restricting further operation of the washing appliance if the monitored change of the liquid level deviates from an expected change of the liquid level.

Thereby, the operational safety of the washing appliance can be improved and the risk of problems such as overheating, fire, component damages, flooding, and the like, can be reduced.

According to a third aspect of the invention, the object is achieved by a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to some embodiments of the present disclosure. Since the computer program comprises instructions which, when the program is executed by a computer, cause the computer to carry out the method according to some embodiments, a computer program is provided which provides conditions for overcoming, or at least alleviating, at least some of the above-mentioned drawbacks. According to a fourth aspect of the invention, the object is achieved by a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to some embodiments of the present disclosure. Since the computer-readable medium comprises instructions which, when the program is executed by a computer, cause the computer to carry out the method according to some embodiments, a computer-readable medium is provided which provides conditions for overcoming, or at least alleviating, at least some of the above-mentioned drawbacks.

According to a fifth aspect of the invention, the object is achieved by a control arrangement for a washing appliance, wherein the washing appliance comprises a liquid container configured to accommodate a liquid, a liquid level indicator unit configured to provide data indicative of a liquid level in the liquid container, a drain conduit, and a drain pump configured to drain the liquid container via the drain conduit, and wherein the control arrangement is configured to: operate the drain pump during a first time period, control the drain pump to a standstill during a second time period following the first time period, and monitor a change of the liquid level during the second time period using data from the liquid level indicator unit.

Since the control arrangement is configured to monitor the change of the liquid level during the second time period, a control arrangement is provided capable of detecting presence of a siphon effect in the drain conduit in a simple and efficient manner. Furthermore, a control arrangement is provided capable of detecting whether liquid is leaving the liquid container for some other reason, such as for example as a result of a leakage.

Moreover, a control arrangement is provided capable of detecting whether liquid is leaving the liquid container in an unexpected manner while the washing appliance has conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. This because such an operational error can be detected using a simple and low cost liquid level indicator unit.

As a further result thereof, conditions are provided for improving the operational safety of the washing appliance, for example by performing one or more appropriate actions if the monitored change of the liquid level deviates from an expected change of the liquid level. In this manner, the operational safety of the washing appliance can be improved, and wrong decisions in control logics of the washing appliance can be avoided, thereby also avoiding potential subsequent problems such as overheating, risk of fire, component damages, flooding, and the like.

Accordingly, a control arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

Fig. 1 schematically illustrates a washing appliance according to some embodiments,

Fig. 2 illustrates a method of detecting an operational error in a washing appliance according to some embodiments, and

Fig. 3 illustrates a computer-readable medium according to some embodiments.

DETAILED DESCRIPTION

Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 schematically illustrates a washing appliance 1 according to some embodiments of the present disclosure. According to the illustrated embodiments, the washing appliance 1 is a dishwasher 1. According to further embodiments, the washing appliance 1 as referred to herein, may be another type of washing appliance 1 , such as a washing machine. The washing appliance 1 comprises a washing chamber 2 configured to accommodate items to be washed. According to the illustrated embodiments, the washing appliance 1 comprises a washing chamber 2 configured to accommodate items such as dishware, cutlery, and the like. Moreover, according to the illustrated embodiments, the washing appliance 1 comprises a set of racks 4 each configured to accommodate the items to be washed in the washing chamber 2. According to the illustrated embodiments, the washing appliance 1 comprises three racks 4. According to further embodiments, the washing appliance 1 may comprise another number of racks 4, such as one or two racks 4.

The washing appliance 1 comprises a number of spray devices 6, which according to the illustrated embodiments are spray arms 6. According to the illustrated embodiments, the washing appliance 1 comprises three spray devices 6. According to further embodiments, the washing appliance 1 may comprise another number of spray devices, such as one, two, four, five, or the like. The washing appliance 1 further comprises a sump 3 at a bottom of the washing chamber 2. The sump 3 is configured to accommodate washing liquid used in a washing process in the washing appliance 1, such as a mixture of water and detergent. Therefore, the sump 3 is referred to as a liquid container 3 herein. Moreover, the washing appliance 1 comprises a door 8 arranged to provide a closure of the washing chamber 2. In Fig. 1, the door 8 is illustrated in a closed position. However, the door 8 can be opened to an open position to provide access to the washing chamber 2.

The washing appliance 1 further comprises a circulation pump 7. The circulation pump 7 is configured to pump washing liquid from the liquid container 3 to the spray devices 6 via a hydraulic circuit 10 during a wash cycle of the dishwasher 1. The liquid is sprayed from the spray devices 6 onto the items to clean the items. Due to gravity, the liquid is collected in the liquid container 3 where it is pumped again by the circulation pump 7 to the spray devices 6.

The washing appliance 1 further comprises a liquid level indicator unit 5, 7 configured to provide data indicative of a liquid level 8 in the liquid container 3. According to some embodiments, the liquid level indicator unit 5 may comprise a sensor 5 configured to sense the liquid level 8 in the liquid container. Such a sensor may for example comprise a pressure switch, a float, a weight measuring device, or the like. As an alternative, or in addition, the circulation pump 7 may be utilized as a liquid level indicator unit 7 to provide data indicative of a liquid level 8 in the liquid container 3. According to such embodiments, data indicative of the liquid level 8 in the liquid container 3 can be obtained by operating the circulation pump 7 and monitoring one or more electrical quantities of the circulation pump 7, such as electric current or electrical voltage. As a still further alternative, or in addition to the above described, the liquid level indicator unit may comprise one or more flow sensors in the hydraulic circuit 10.

The washing appliance 1 further comprises a drain conduit 15 and a drain pump 13. The drain pump 13 is configured to drain the liquid container 3 via the drain conduit 15. The drain conduit 15 is configured to be connected to a drain 16 upon installation of the washing appliance 1. The drain conduit 15 comprises a flexible hose 17 intended to be installed such that at least part of the drain conduit 15 is routed via a point located higher than the liquid container 3.

The washing appliance 1 further comprises a control arrangement 9. The control arrangement 9 is configured to control operation of the circulation pump 7 and the drain pump 13. Moreover, the control arrangement 9 may be configured to control the operation of further arrangements, systems, and/or subsystems of the washing appliance 1 , such as one ore more heat elements, one or more valve arrangements, or the like.

According to embodiments herein, the control arrangement 9 of the washing appliance 1 is configured to: operate the drain pump 13 during a first time period, control the drain pump 13 to a standstill lasting during a second time period following the first time period, and monitor a change of the liquid level 8 during the second time period using data from the liquid level indicator unit 5, 7.

Since the control arrangement 9 is configured to monitor the change of the liquid level 8 during the second time period, the change of the liquid level 8 is monitored in a time period, i.e. the second time period, in which the drain pump 13 does not operate. Moreover, since the second time period follows the first time period, the change of the liquid level 8 is monitored in a time period, i.e. the second time period, in which the drain pump 13 recently has operated. Therefore, the drain pathways, such as the drain conduit 15, is filled with liquid when the second time period starts. As a result thereof, a washing appliance 1 is provided in which the control arrangement 9 can monitor the change of the liquid level 8 so as to detect the presence of a siphon effect in the drain conduit 15, as is further explained herein. In the above described control procedure performed by the control arrangement 9, the second time period may start when the drain pump 13 reaches a standstill. Moreover, the second time period may immediately follow the first time period. Since the drain pump 13 is inactive during the second time period, the second time period may also be referred to as a pause period of the drain pump 13.

A siphon effect can occur in the drain conduit 15 when the drain conduit 15 is filled with liquid causing liquid to be drawn from the liquid container in an unexpected manner also when the drain pump 13 is inactive. A siphon effect in the drain conduit 15 may be caused by the fact that the drain conduit 15 is installed at too low height relative to the liquid container 3 and/or if the connection of the drain conduit 15 to the drain 16 seals without any free path between the drain conduit 15 and ambient air for pressure equalization.

In some cases, a siphon effect in the drain conduit 15 may be caused by the fact that the drain conduit 15 has become loose from the drain connection. If so, large amounts of liquid may be drained inside/under cabinets and floors/walls. Moreover, a siphon effect in the drain conduit 15 may lead to several wrong decisions in control logics of the washing appliance, with potential subsequent problems such as overheating, increased risk of fire, component damages, flooding, and the like.

Since the control arrangement 9 of the washing appliance 1 according to the present disclosure is configured to monitor the change of the liquid level 8 during the second time period, a washing appliance 1 is provided capable of detecting presence of a siphon effect in the drain conduit 15. Furthermore, a washing appliance 1 is provided capable of detecting whether liquid is leaving the liquid container 3 for some other reason, such as for example as a result of a leakage.

According to some embodiments, the control arrangement 9 is configured to monitor the change of the liquid level 8 by detecting the liquid level 8 at two or more points in time within the second time period and comparing the detected liquid levels 8 at the respective two or more points in time. According to further embodiments, the control arrangement 9 may be configured to continuously monitoring the change of the liquid level 8.

As indicated above, according to the illustrated embodiments, the control arrangement 9 may be configured to monitor the change of the liquid level 8 by operating the circulation pump 7 and monitor one or more electrical quantities of the circulation pump 7. The electrical quantities of the circulation pump 7 is indicative of the liquid level 8 because a higher liquid level increases the pumping resistance, and the duration in which a higher pumping resistance is obtained, which in turn affects the electrical quantities of the circulation pump 7.

The control arrangement 9 may be configured to compare the monitored change of the liquid level 8 with an expected change of the liquid level 8. As is further explained herein, the control arrangement 9 may be configured to perform at least one of a corrective measure and a safety measure if the monitored change of the liquid level 8 deviates from the expected change of the liquid level 8. According to the illustrated embodiments, the washing appliance 1 comprises an output unit 11. The output unit 11 may comprise one or more of a display, a speaker, a communication module 1 T, or the like. The control arrangement 9 may be configured to output a notification via the output unit 11 if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8. The output of a notification can be seen as a safety measure. According to the illustrated embodiments, the output unit 11 comprises communication module 1T configured to communicate wirelessly with an external communication unit 22. The communication module 1T may be configured to wirelessly transmit data to, and/or receive data from, a remote wireless network router 22, for example a Wi-Fi router. The wireless communication may for example be performed over a wireless connection such as the internet, or a wireless local area network (WLAN), or a wireless connection for exchanging data over short distances using short-wavelength, i.e. ultra-high frequency (UHF) radio waves in the industrial, scientific and medical (ISM) band from 2.4 to 2.485 GHz.

Moreover, according to some embodiments of the present disclosure, the control arrangement 9 may be configured to output a notification wirelessly via the output unit 11 to an external user device 26, such as a computer, a computer tablet, or a mobile phone 26, if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8. Such wireless communication may be performed via a mobile communication network, a wireless network router 22, a wireless local area network (WLAN), or a wireless connection for exchanging data over short distances using short-wavelength, i.e. ultra-high frequency (UHF) radio waves in the industrial, scientific and medical (ISM) band from 2.4 to 2.485 GHz. Moreover, according to some embodiments of the present disclosure, the control arrangement 9 may be configured to output a notification wirelessly via the output unit 11 to an external service centre or service centre personnel.

According to some embodiments, the control arrangement 9 may be configured to perform a corrective measure if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8, and wherein the corrective measure comprises at least one of: changing an operational time of a wash cycle of the washing appliance 1 , delaying an operational step of a wash cycle of the washing appliance 1 , and changing an amount of liquid filled into the liquid container 3.

As an alternative, or in addition, the control arrangement 9 may be configured to perform an at least partial restriction of further operation of the washing appliance 1 if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8. According to some embodiments, the control arrangement 9 may be configured to separate between changes of the liquid level 8 caused by a siphon effect and changes of the liquid level 8 caused by another reason. According to such embodiments, the control arrangement 9 may be configured to select an appropriate measure based on the cause of the change of the liquid level 8.

The following is an example of possible control performed by the control arrangement 9. In the example, the liquid container 3 is to be drained and refilled between a first and a second washing cycle of a washing program. Purely as an example, the liquid level is 4 litres at the end of the first washing cycle. The control arrangement 9 operates the drain pump 13 during a first time period and cancels operation of the drain pump 13 when the expected pumped volume of liquid is 1.5 litres, which is enough to fill the drain pathways and the drain conduit 15 with liquid. The control arrangement 9 then monitors the change of the liquid level 8 during the second time period, using data from the liquid level indicator unit 5, 7. As mentioned above, the second time period starts when the drain pump 13 is at standstill. In this example, the expected liquid level in the liquid container 3 is 2.5 litres and the expected change of the liquid level 8 is zero, at least when some time has elapsed from the beginning of the second time period. At the beginning of the second time period, the liquid level in the liquid container 3 is expected to increase. This because it is expected that liquid being pumped during the first time period will flow backwards from the drain pathways and the drain conduit 15 through the drain pump 13 into the liquid container 3. If no such increase is detected when monitoring the change of the liquid level 8 using data from the liquid level indicator unit 5, 7, a siphon effect in the drain conduit 15 can be expected to occur.

Moreover, if the liquid level indicator unit 5, 7 provides data indicating that the liquid level 8 in the liquid container 3 is well below 2.5 litres when some time has elapsed from the beginning of the second time period, a siphon effect in the drain conduit 15 can be expected to have occurred.

If more liquid is emptied from the liquid container 3 than expected, and the cause thereof is expected to be a siphon effect in the drain conduit 15, the control arrangement 9 may perform a pause until the siphon effect is expected to end, and then perform a full fill of liquid into the liquid container 3 instead of a partial fill of liquid into the liquid container 3. The control arrangement 3 may fill the liquid container 3 by opening a valve provided in a water inlet conduit. The valve and the water inlet conduit are not illustrated in Fig. 1 for the reason of brevity and clarity. The control arrangement 9 may then continue the washing program by initiating the second washing cycle and notify a user, a service centre, and/or service centre personnel, via the output unit 11 that the installation of the drain conduit 15 should be checked. Fig. 2 illustrates a method 100 of detecting an operational error in a washing appliance. The method 100 may be performed on a washing appliance 1 according to the embodiments illustrated in Fig. 1. Therefore, below, simultaneous reference is made to Fig. 1 and Fig. 2. The method illustrated in Fig. 2 is a method 100 of detecting an operational error in a washing appliance 1, wherein the washing appliance 1 comprises a liquid container 3 configured to accommodate a liquid, a liquid level indicator unit 5, 7 configured to provide data indicative of a liquid level 8 in the liquid container 3, a drain conduit 15, and a drain pump 13 configured to drain the liquid container 3 via the drain conduit 15, and wherein the method 100 comprises the steps of: operating 110 the drain pump 13 during a first time period, controlling 120 the drain pump 13 to a standstill lasting during a second time period following the first time period, and monitoring 130 a change of the liquid level 8 during the second time period using data from the liquid level indicator unit 5, 7.

As indicated in Fig. 2, the step of monitoring 130 the change of the liquid level 8 may comprise the step of: monitoring 131 the change of the liquid level 8 so as to detect the presence of a siphon effect in the drain conduit 15.

According to some embodiments, the washing appliance 1 comprises a circulation pump 7, and as indicated in Fig. 2, the step of monitoring 130 the change of the liquid level 8 may comprise the steps of: activating 132 operation of the circulation pump 7, and monitoring 133 one or more electrical quantities of the circulation pump 7.

Moreover, as indicated in Fig. 2, the step of monitoring 130 the change of the liquid level 8 may comprise the steps of: detecting 134 the liquid level 8 at two or more points in time, and comparing 135 the liquid levels 8 detected at the two or more points in time.

Moreover, as indicated in Fig. 2, the method 100 may further comprise the step of: performing 140 at least one of a corrective measure and a safety measure if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8. According to some embodiments, the washing appliance 1 comprises an output unit 11, and as indicated in Fig. 2, the method 100 may comprise the step of: outputting 150 a notification via the output unit 11 if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8.

Moreover, as indicated in Fig. 2, the method may further comprise the steps of: performing 141 a corrective measure if the monitored change of the liquid level

8 deviates from an expected change of the liquid level 8, and wherein the corrective measure comprises at least one of: changing 142 an operational time of a wash cycle of the washing appliance 1 , delaying 143 an operational step of a wash cycle of the washing appliance 1 , and changing 144 an amount of liquid filled into the liquid container 3.

Furthermore, as indicated in Fig. 2, the method may further comprise the step of: at least partial restricting 145 further operation of the washing appliance 1 if the monitored change of the liquid level 8 deviates from an expected change of the liquid level 8.

It will be appreciated that the various embodiments described for the method 100 are all combinable with the control arrangement 9 as described herein. That is, the control arrangement 9 may be configured to perform any one of the method steps 110, 120, 130,

131, 132, 133, 134, 135, 140, 141, 142, 143, 144, 145, and 150 of the method 100.

Fig. 3 illustrates a computer-readable medium 200 comprising instructions which, when executed by a computer, cause the computer to carry out the method 100 according to some embodiments of the present disclosure.

According to some embodiments, the computer-readable medium 200 comprises a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method 100 according to some embodiments.

One skilled in the art will appreciate that the method 100 of detecting an operational error in a washing appliance 1 may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in the control arrangement 9, ensures that the control arrangement 9 carries out the desired control, such as the method steps 110, 120, 130, 131, 132, 133, 134, 135, 140, 141, 142, 143, 144, 145, and 150 described herein. The computer program is usually part of a computer program product 200 which comprises a suitable digital storage medium on which the computer program is stored.

The control arrangement 9 may comprise a calculation unit which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

The control arrangement 9 may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e. , sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

The control arrangement 9 is connected to components of the washing appliance 1 for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement 9. These signals may then be supplied to the calculation unit. One or more output signal sending devices may be arranged to convert calculation results from the calculation unit to output signals for conveying to other parts of the control system of the washing appliance 1 and/or the component or components for which the signals are intended. Each of the connections to the respective components of the washing appliance 1 for receiving and sending input and output signals may take the form of one or more from among a cable, a wireless connection, or the like. In the embodiments illustrated, the washing appliance 1 comprises a control arrangement 9 but might alternatively be implemented wholly or partly in two or more control arrangements or two or more control units.

The computer program product 200 may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the method steps 110, 120, 130, 131, 132, 133, 134, 135, 140, 141, 142, 143, 144, 145, and 150 according to some embodiments when being loaded into one or more calculation units of the control arrangement 9. The data carrier may be, e.g. a CD ROM disc, as is illustrated in Fig. 3, or a ROM (read-only memory), a PROM (programable read-only memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. The computer program product may furthermore be provided as computer program code on a server and may be downloaded to the control arrangement 9 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems.

As indicated above, according to the illustrated embodiments, the washing appliance 1 comprises a liquid container 3 in the form of a sump 3. Therefore, throughout this disclosure, the wording “liquid container” may be replaced by the wording “sump”.

It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions, or groups thereof.