# US 2021/0277587 A1 · Laundry dryer and method for controlling the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0277587 A1 - Document ID: US20210277587A1 - Status: Published application - Kind: A1 - Application number: 17/191,147 - Filed: 2021-03-03 - Published: 2021-09-09 - Earliest claimed: 2020-03-04 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Juhan YOON; Manseok LEE; Hyojin JOO - Web page: https://patentgrep.com/patent/US20210277587A1 ## CPC - D06F 58/44: of conditioning or finishing, e.g. for smoothing or removing creases - D06F 58/203: {Laundry conditioning arrangements} - D06F 33/30: Control of washing machines characterised by the purpose or target of the control (controlling processes of washer-dryers D06F33/50) - D06F 34/14: Arrangements for detecting or measuring specific parameters - D06F 39/085: {Arrangements or adaptations of pumps} - D06F 39/40: Steam generating arrangements - D06F 58/04: Details (controlling or regulating devices D06F34/00) - D06F 2103/62: related to systems for water or steam used for conditioning or finishing - D06F 2105/40: using water or steam - D06F 2105/58: Indications or alarms to the control system or to the user - D06F 2105/60: Audible signals - D06F 2105/62: Stopping or disabling machine operation - D06F: LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES ## Abstract A laundry dryer performs a method for drying laundry with steam or hot air and notifying a user of water shortage. The laundry dryer includes a cabinet, a drum, a steam unit, a storage tank, a supply pump, and a steam controller. The steam controller operates the steam unit upon receiving a steam supply command to supply steam to the drum. When a water level of water stored in at least one of the steam unit or the storage tank is equal to or less than a predetermined water level, the steam controller provides a water shortage notification message for user recognition. The laundry dryer provides the water shortage notification message when a minimum amount of residual water is stored in the storage tank. The number of times to refill the storage tank can be minimized, resulting in an increase in user convenience. ## Claims ### Claim 1 A laundry dryer comprising: a cabinet; a drum disposed in the cabinet and configured to receive hot air or steam or both; a steam unit disposed in the cabinet and configured to generate the steam; a storage tank disposed in the cabinet and configured to store water; a supply pump disposed between the steam unit and the storage tank, the supply pump being configured to supply the water stored in the storage tank to the steam unit; and a steam controller configured to: operate the steam unit based on receiving a steam supply command for supplying the steam to the drum, determine a water level of water the steam unit or the storage tank, and based on the water level of water in the steam unit or the storage tank being less than or equal to a predetermined water level, output a water shortage notification. ### Claim 2 (depends on 1) The laundry dryer according to claim 1, wherein the steam controller is configured to: based on completion of supply of steam into the drum, operate the supply pump to thereby supply water to the steam unit to a predetermined target water level of the steam unit. ### Claim 3 (depends on 2) The laundry dryer according to claim 2, wherein the steam controller is configured to: determine the water level in the steam unit after supplying water to the steam unit for a predetermined time from an operation start time of the supply pump; and determine a water shortage state of the storage tank based on the water level in the steam unit being less than the predetermined target water level after supplying the water to the steam unit for the predetermined time from the operation start time of the supply pump. ### Claim 4 (depends on 3) The laundry dryer according to claim 3, wherein the steam controller is configured to: output the water shortage notification based on determining the water shortage state of the storage tank or based on receiving a subsequent steam supply command after determining the water shortage state of the storage tank. ### Claim 5 (depends on 2) The laundry dryer according to claim 2, wherein the steam unit comprises: a steam generator configured to store water supplied from the storage tank and to generate the steam; a spray nozzle configured to spray the steam generated by the steam generator into the drum; a water supply pipe that connects the supply pump to the steam unit and is configured to supply water from the storage tank to the steam generator; and a steam discharge pipe that connects the steam generator to the spray nozzle and is configured to supply the steam generated by the steam generator to the spray nozzle. ### Claim 6 (depends on 5) The laundry dryer according to claim 5, wherein the steam generator comprises: a steam housing configured to receive water from the storage tank; a heater configured to heat water in the steam housing; and a water level sensor configured to sense a water level of water in the steam housing. ### Claim 7 (depends on 6) The laundry dryer according to claim 6, wherein the water level sensor comprises: a low water level sensor configured to detect whether the water level of water stored in the steam housing is greater than or equal to a minimum water level that is predetermined to maintain the heater in the water stored in the steam housing; and a high water level sensor configured to detect whether the water level of water stored in the steam housing corresponds to a target water level that is predetermined for steam generation. ### Claim 8 (depends on 7) The laundry dryer according to claim 7, wherein the low water level sensor comprises a low water level electrode disposed at a position corresponding to the minimum water level, wherein the high water level sensor comprises a high water level electrode disposed at a position corresponding to the target water level, and wherein the water level sensor further comprises a common electrode disposed at a position vertically lower than or equal to the position of the low water level electrode, the common electrode being electrically connected to at least one of the low water level electrode or the high water level electrode through the water stored in the steam housing and configured to detect the water level of water stored in the steam housing. ### Claim 9 (depends on 7) The laundry dryer according to claim 7, wherein the steam controller is configured to: determine the water level of water stored in the steam housing after supplying water to the steam unit for a predetermined time from an operation start time of the supply pump; and output the water shortage notification based on the water level of water stored in the steam housing being less than the target water level after supplying the water to the steam unit for the predetermined time from the operation start time of the supply pump. ### Claim 10 (depends on 7) The laundry dryer according to claim 7, wherein the steam controller is configured to: based on the water level of water stored in the steam housing being less than the minimum water level, operate the supply pump to thereby supply water to the steam housing to a level greater than or equal to the minimum water level. ### Claim 11 (depends on 1) The laundry dryer according to claim 1, wherein the steam controller is configured to output the water shortage notification through at least one of a display panel or a speaker. ### Claim 12 A method for controlling a laundry dryer including a drum configured to receive laundry therein, a steam unit configured to generate steam, a storage tank configured to store water, and a supply pump configured to supply the water stored in the storage tank to the steam unit, the method comprising: performing a drying process, the drying process comprising supplying at least one of hot air or steam to the drum; supplying the steam to the drum; based on completion of supply of steam to the drum, supplying water stored in the storage tank to the steam unit by operating the supply pump; after completion of supply of water to the steam unit, determining a water level of water in the steam unit or in the storage tank; based on the water level of water in the steam unit or the storage tank being less than or equal to a predetermined water level, determining a water shortage state; and outputting a water shortage notification that indicates the water shortage state. ### Claim 13 (depends on 12) The method according to claim 12, wherein supplying the water stored in the storage tank to the steam unit comprises: operating the supply pump at an operation start time of the supply pump to thereby supply water to the steam unit until the water level of water in the steam unit corresponds to a predetermined target water level; and stopping operation of the supply pump based on the water level of water in the steam unit corresponding to the predetermined target water level or based on an elapse of a predetermined time from the operation start time of the supply pump. ### Claim 14 (depends on 12) The method according to claim 12, wherein supplying the water stored in the storage tank to the steam unit comprises: stopping operation of the supply pump based on an elapse of a predetermined time from a specific time in which an electric current applied to the supply pump is maintained at a constant level or load is not applied to the supply pump. ### Claim 15 (depends on 13) The method according to claim 13, wherein determining the water shortage state comprises: determining the water level of water in the steam unit after supplying water to the steam unit for the predetermined time from the operation start time of the supply pump; and determining the water shortage state based on the water level of water in the steam unit being less than the predetermined target water level after the elapse of the predetermined time from the operation start time of the supply pump. ### Claim 16 (depends on 15) The method according to claim 15, wherein outputting the water shortage notification comprises: outputting the water shortage notification based on determining the water shortage state. ### Claim 17 (depends on 15) The method according to claim 15, wherein outputting the water shortage notification comprises: outputting the water shortage notification based on receiving a subsequent steam supply command after determining the water shortage state. ### Claim 18 (depends on 12) The method according to claim 12, wherein determining the water shortage state comprises: sensing the water level of water stored in the storage tank; sensing the water level of water stored in the steam unit; and determining the water shortage state based on (i) the water level of water stored in the storage tank being less than or equal to the predetermined water level and (ii) the water level of water stored in the steam unit being less than a predetermined target water level. ### Claim 19 (depends on 12) The method according to claim 12, wherein outputting the water shortage notification comprises: outputting the water shortage notification through at least one of a display panel or a speaker. ### Claim 20 (depends on 12) The method according to claim 12, further comprising: based on receiving a drying process command after outputting the water shortage notification, determining whether the water level of water stored in the steam unit corresponds to a predetermined target water level; and based on determining that the water level of water stored in the steam unit corresponds to the predetermined target water level, supplying the hot air to the drum.