# US 10,244,919 B2 · Detecting operational state of a dishwasher > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,244,919 B2 - Document ID: US10244919B2 - Status: Granted - Kind: B2 - Application number: 14/439,351 - Filed: 2012-11-08 - Published: 2015-10-29 - Granted: 2019-04-02 - Earliest claimed: 2012-11-08 - Assignees: Electrolux Home Products, Inc. - Applicants: Electrolux Home Products Corporation N. V. - Inventors: Per-Erik Pers; Petter Svanbom - Web page: https://patentgrep.com/patent/US10244919B2 ## CPC - A47L 15/4244: {Water-level measuring or regulating arrangements} - A47L 15/0023: {Water filling (A47L15/4244 takes precedence)} - A47L 15/0049: {Detection or prevention of malfunction, including accident prevention (arrangements to prevent clogging of filters A47L15/4208; safety arrangements for preventing water damage A47L15/421)} - A47L 15/4289: {Spray-pressure measuring or regulating arrangements (nozzles A47L15/4278)} - A47L 2301/04: Operation mode, e.g. delicate washing, economy washing, reduced time, sterilizing, water softener regenerating, odor eliminating or service - A47L 2401/03: Operation mode, e.g. delicate washing, economy washing, reduced time, sterilizing, water softener regenerating, odor eliminating or service - A47L 2401/08: Drain or recirculation pump parameters, e.g. pump rotational speed or current absorbed by the motor - A47L 2501/05: Drain or recirculation pump, e.g. regulation of the pump rotational speed or flow direction - A47L 2501/26: Indication or alarm to the controlling device or to the user - A47L 2501/30: Regulation of machine operational steps within the washing process, e.g. performing an additional rinsing phase, shortening or stopping of the drying phase, washing at decreased noise operation conditions - A47L 2501/34: Change machine operation from normal operational mode into special mode, e.g. service mode, resin regeneration mode, sterilizing mode, steam mode, odour eliminating mode or special cleaning mode to clean the hydraulic circuit - A47L: DOMESTIC WASHING OR CLEANING (brushes A46B; cleaning quantities of bottles or of other hollow articles of one kind B08B9/00; laundry D06F); SUCTION CLEANERS IN GENERAL (cleaning in general B08) ## Abstract The present invention relates to a method of and a device (40) for, detecting an operational state of a dishwasher (10), in particular activation of extra wash zones and overfill situations. The device (40) is arranged to operate a motor (22) driving a dishwasher circulation pump (21) at at least one rotational speed differing from a nominal rotational speed and measure operating current of the motor (22) driving the dishwasher circulation pump (21). Further, the device is arranged to determine whether the dishwasher (10) operates in an operational state differing from a nominal operational state based on the measured circulation pump motor operating current. ## Claims ### Claim 1 A method of detecting an operational state of a dishwasher, the dishwasher comprising a dishwasher circulation pump, the dishwasher being configured to operate at least a first washing cycle, wherein (a) during the first washing cycle the circulation pump is caused to be operated at a first rotational speed and (b) the first washing cycle corresponds to a first operational state, the method comprising the steps of: causing operation of a motor driving the dishwasher circulation pump to operate the dishwasher circulation pump at a second rotational speed, the second rotational speed differing from the first rotational speed; measuring operating current of the motor driving the dishwasher circulation pump in response to causing operation of the motor driving the dishwasher circulation pump at the second rotational speed; determining whether the dishwasher operates in a second operational state differing from the first operational state based on the measured circulation pump motor operating current at the second rotational speed, wherein the second rotational speed is selected based on a change in operating current of the motor being more easily detected at the second rotational speed than at the first rotational speed. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of operating a motor driving a dishwasher circulation pump comprises: operating the motor driving the dishwasher circulation pump at the second rotational speed, wherein the second rotational speed is lower than the first rotational speed; and the step of determining operational state comprises: determining whether an extra wash zone has been activated based on a measured increase in the circulation pump motor operating current. ### Claim 3 (depends on 2) The method of claim 2, said motor driving the dishwasher circulation pump being operated at the second rotational speed for a predetermined time period at a beginning of a washing program. ### Claim 4 (depends on 3) The method of claim 3, further comprising the step of: increasing the rotational speed of the motor driving the dishwasher circulation pump to the first rotational speed in response to (a) detecting that the extra wash zone has been activated or (b) after the predetermined time period elapses and activation of the extra wash zone has not been detected. ### Claim 5 (depends on 2) The method of claim 2 wherein the step of determining whether an extra wash zone has been activated based on the measured increase in circulation pump motor operating current comprises: comparing the measured circulation pump motor operating current to a first predetermined current threshold value, wherein the extra wash zone is considered to be activated if the measured current exceeds the first predetermined current threshold value. ### Claim 6 (depends on 2) The method of claim 2, further comprising the step of: initiating, if activation of an extra wash zone is detected, an action selected based on a washing program selected by the user. ### Claim 7 (depends on 1) The method of claim 1, wherein the step of operating a motor driving a dishwasher circulation pump comprises: operating the motor driving the dishwasher circulation pump at the second rotational speed being higher than the first rotational speed; and the step of determining operational state comprises: determining whether the dishwasher is overfilled based on a measured increase in the circulation pump motor operating current, wherein the dishwasher is overfilled when the amount of processing water within a washing compartment of the dishwasher is in excess of an amount of processing water within the washing compartment during a normal washing cycle. ### Claim 8 (depends on 7) The method of claim 7, further comprising the step of: decreasing the rotational speed of the motor driving the dishwasher circulation pump to the first rotational speed if it is determined that the dishwasher is not overfilled. ### Claim 9 (depends on 7) The method of claim 7, wherein the step of determining whether the dishwasher is overfilled based on a measured increase in circulation pump motor operating current comprises: comparing the measured circulation pump motor operating current to a second predetermined current threshold value, wherein the dishwasher is considered to be overfilled if the measured current exceeds the second predetermined current threshold value. ### Claim 10 (depends on 7) The method of claim 7, further comprising the step of: draining the dishwasher of an appropriate amount of excess process water if it is determined that the dishwasher is overfilled. ### Claim 11 (depends on 10) The method of claim 10, further comprising the step of: after draining the appropriate amount of excess process water, determining if the dishwasher is overfilled; and terminating a current washing cycle if it is determined that the dishwasher is overfilled after draining the dishwasher of the appropriate amount of excess process water. ### Claim 12 (depends on 7) The method of claim 7, further comprising the step of: signaling, via an indicator of the dishwasher, that the dishwasher is overfilled if it is determined that the dishwasher is overfilled.