Engineers from Carrier have developed range hoods that can monitor their own weight, and use the information to determine whether they are due for a cleaning.
The Florida-based home appliances manufacturer’s patent application mentions how kitchen hoods can become caked with grease as they extract smoke emitted during cooking. Spot-check sensors serve as a common maintenance tool, but Carrier notes that these tools cannot indicate grease levels across a whole ventilation hood system.
This imprecise method can be an inconvenience for restaurants that schedule range hood cleanings: too frequent means greater financial costs and time consumption—an average cleaning job can charge around several hundred dollars. Meanwhile, scheduling cleanings too infrequently can lead to poorer air quality and reduced sanitation in a kitchen.
Carrier’s filing suggested a ventilation hood design composed of the appliance body through which cooking vapors pass, a support system affixed to the body and a weight sensing system operably coupled to the support system. The apparatus may also include duct sidewalls enclosing the interior or a screen for cooking vapors. Legs that may be connected to the support system may alternatively be configured to sense a portion of the hood body’s entire weight.
Illustrations of a ventilation hood system in clean [left] and dirty [right] conditions. See the extended legs  due to grease buildup in the appliance.
For kitchen hoods without support legs, the support system would come equipped with weight sensors consisting of at least one load cell and strain gauge. Data gathered over time can be compared to a range hood’s baseline weight when it was clean. A fixed or portable computing device can process the information to determine when grease buildup has exceeded a predefined level. Carrier says this threshold may be manually or automatically adjustable over time.
The patent application says that by adding a weight-sensing feature, cleaning vent hoods don’t have to be scheduled based on time but only when it’s needed. This monitoring method can lead to cost savings for large kitchens, and a better environment for those working in them.
The featured patent application, “Exhaust Hood Weight Sensor”, was filed with the USPTO on May 13, 2019 and published thereafter on July 15, 2021. The listed applicant is Carrier Corporation. The listed inventors are Thomas Carl Kjellman and Melissa B. Avila.