# US 12,111,094 B2 · Refrigerated device with door open sensor fault identification > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,094 B2 - Document ID: US12111094B2 - Status: Granted - Kind: B2 - Application number: 17/479,450 - Filed: 2021-09-20 - Published: 2022-03-31 - Granted: 2024-10-08 - Earliest claimed: 2020-09-28 - Assignees: Illinois Tool Works Inc. - Applicants: Illinois Tool Works Inc. - Inventors: Steven T. Jackson - Web page: https://patentgrep.com/patent/US12111094B2 ## CPC - F25D 21/14: Collecting or removing condensed and defrost water; Drip trays - F25D 21/02: Detecting the presence of frost or condensate - F25D 29/00: Arrangement or mounting of control or safety devices - F25D 2321/143: characterised by means to fix, clamp, or connect water pipes or evaporation trays - F25D 2321/1441: inside a refrigerator - F25D 2400/04: Refrigerators with a horizontal mullion - F25D 2500/04: Calculation of parameters - F25D 2700/02: Sensors detecting door opening - F25D 2700/12: Sensors measuring the inside temperature - F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B) ## Abstract A refrigerated device includes a compartment including an access door. A refrigeration circuit for cooling the compartment includes an evaporator coil with an associated evaporator fan and a condenser with an associated condenser fan. A temperature sensor is provided for indicating a compartment temperature within the compartment. A controller is configured to: (i) monitor the compartment temperature in order to approximate a number of door openings, (ii) compare the approximated number of door openings to a data point and (iii) take a control action based upon a certain result of the comparison. ## Claims ### Claim 1 A refrigerated device, comprising: a compartment including an access door; a refrigeration circuit for cooling the compartment, the refrigeration circuit including an evaporator coil with an associated evaporator fan and a condenser with an associated condenser fan; a door sensor positioned for identifying an open condition of the access door; a temperature sensor for indicating a compartment temperature within the compartment; a controller configured to: (i) monitor the compartment temperature indicated by the temperature sensor, (ii) repeatedly calculate a first derivative of the compartment temperature and increment an expected door open count if the first derivative of the compartment temperature rises, (iii) monitor the door sensor to maintain a door sensor based door open count, (iv) compare the expected door open count to the door sensor based door open count, (v) determine that the door open sensor is malfunctioning based on a discrepancy between the door sensor based door open count and the expected door open count, and (vi) take a control action based upon the discrepancy. ### Claim 2 (depends on 1) The refrigerated device of claim 1, wherein the controller is configured to take the control action if the discrepancy is above a set threshold. ### Claim 3 (depends on 1) The refrigerated device of claim 1, wherein the discrepancy is the expected door open count being greater than the door sensor-based door open count by a set number. ### Claim 4 (depends on 3) The refrigerated device of claim 3, wherein the control action is changing a logic used for establishing when to initiate a defrost operation. ### Claim 5 (depends on 3) The refrigerated device of claim 3, wherein the control action is setting a duration for running a condensate pan heater. ### Claim 6 (depends on 1) The refrigerated device of claim 1, wherein the controller is configured to compare the expected door open count to the door sensor based door open count by (i) determining a difference between the expected door open count and the door sensor based door open count or (ii) determining a ratio between the expected door open count and the door sensor based door open count. ### Claim 7 A refrigerated device, comprising: a compartment including an access door; a refrigeration circuit for cooling the compartment; a door sensor positioned for identifying an open condition of the access door; a controller configured to: (i) monitor the compartment temperature indicated by a temperature sensor, (ii) repeatedly calculate a first derivative of the compartment temperature and increment an expected door open count if the first derivative of the compartment temperature rises above a set threshold, (iii) monitor the door sensor to maintain a door sensor based door open count, (iv) compare the expected door open count to the door sensor based door open count, (v) determine that the door open sensor is malfunctioning based on a discrepancy between the door sensor based door open count and the expected door open count, and (vi) take a control action based upon the discrepancy. ### Claim 8 (depends on 1) The refrigerated device of claim 1, wherein the controller is configured to increment the expected door open count if the first derivative of the compartment temperature rises above a set threshold. ### Claim 9 (depends on 7) The refrigerated device of claim 7, wherein the controller is further configured to compare the expected door open count to a data point. ### Claim 10 (depends on 9) The refrigerated device of claim 9, wherein the controller is further configured to take the control action for the refrigerated device based upon a certain result of the comparison. ### Claim 11 (depends on 9) The refrigerated device of claim 9, wherein the controller is configured to compare the expected door open count to the data point by (i) determining a difference between the expected door open count and the data point or (ii) determining a ratio between the expected door open count and the data point. ### Claim 12 (depends on 8) The refrigerated device of claim 8, wherein the controller is configured such that the expected door open count is reset to zero after a defrosting operation of the refrigeration circuit. ### Claim 13 A method of controlling a refrigerated device that includes a compartment including an access door, a refrigeration circuit for cooling the compartment, a door sensor positioned for identifying an open condition of the access door, a temperature sensor for indicating a compartment temperature within the compartment, and a controller, the method comprising: monitoring the compartment temperature; repeatedly calculating a first derivative of the compartment temperature and incrementing an expected door open count if the first derivative of the compartment temperature rises above a set threshold; monitoring the door sensor to maintain a door sensor based door open count; comparing the expected door open count to the door sensor based door open count; determining that the door open sensor is malfunctioning based on a discrepancy between the door sensor based door open count and the expected door open count; and taking a control action based upon the discrepancy. ### Claim 14 (depends on 13) The method of claim 13, further comprising: implementing the control action for the refrigerated device based, at least in part, upon the expected door open count. ### Claim 15 (depends on 13) The method of claim 13, further comprising, comparing the expected door open count to the data point by (i) determining a difference between the expected door open count and the data point or (ii) determining a ratio between the expected door open count and the data point. ### Claim 16 (depends on 14) The method of claim 14, wherein based upon a certain result of the comparing step, initiating the control action of the refrigerated device. ### Claim 17 (depends on 7) The refrigerated device of claim 7, wherein based upon a certain result of the comparing step, the control action of the refrigerated device is initiated.