Household Oven Humidity Control Using Indirect Sensor Placement
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Solution Overview
Problem
Existing household appliances, such as ovens, face challenges in efficiently controlling humidity levels during cooking processes, particularly due to the limitations of existing humidity measurement and control systems, which are often expensive, prone to pollution, and ineffective in high-temperature environments, leading to suboptimal cooking results and high energy usage.
Innovation Solution
A method and apparatus for controlling humidity in a household appliance using a relatively inexpensive humidity sensor and a temperature sensor, where the sensors' readings are correlated to a matrix to estimate the actual humidity level, allowing for closed-loop control of steam generation and ventilation to maintain desired humidity levels within the cooking cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a humidity sensor is placed directly within the cooking cavity to measure humidity, then measurement precision is improved, but the sensor is exposed to high temperatures and pollution from cooking fumes, grease, and vapors, reducing reliability and increasing cost
Solution Approach 1:
The patent introduces a cooling channel as an intermediary medium between the cooking cavity and the humidity sensor. This cooling channel carries cooling air that mixes with the cavity air, allowing the sensor to indirectly measure cavity humidity while being protected from direct exposure to high temperatures and pollutants. The cooling channel acts as a buffer zone that preserves measurement accuracy while shielding the sensor from harsh conditions.
2Measurement precision
If expensive specialized sensors are used to measure humidity in the cooking cavity, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a copied environment in the cooling channel that replicates the humidity conditions of the cooking cavity without replicating the harmful high-temperature environment. By measuring humidity in this copied, cooler air stream, the system obtains accurate cavity humidity data using simple, inexpensive sensors while avoiding the need for costly high-temperature resistant sensors.
3Reliability
If steam generation is continuously operated to maintain humidity, then humidity control is improved, but energy consumption increases
Solution Approach 1:
The patent implements a feedback control system where the humidity sensor continuously monitors the actual humidity level in the cooking cavity through the cooling channel. This measurement is fed back to the control unit, which compares it with the desired humidity setpoint and adjusts steam generation accordingly. This closed-loop feedback enables precise humidity control while minimizing energy consumption by operating the steam generator only when and to the extent needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient and cost-effective humidity control in household appliances, independent of direct humidity measurement within the cavity, improving cooking performance, reducing energy consumption, and enhancing user convenience by maintaining optimal humidity conditions during various cooking phases.
Implementation Method 1
said compartment comprises at least one mixing element (7) for mixing and/or diluting a fluid from the cavity (3) with air
Implementation Method 2
said compartment comprises at least one fan element (7) for ventilating a fluid from and/or into said cavity (3)
Data Source
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AI summary
Household appliance (1) for cooking and/or baking food stuffs or bakery ware (2) comprising a heatable cavity (3) for placing the food stuffs or bakery ware (2), an access door (4) for accessing the cavity (3), a compartment (5) located exterior of said cavity (3), said compartment being in fluid communication with said cavity (3) by at least one duct (6), a control unit (10), at least one first sensor (8) located in the compartment (5) and being connected to the control unit (10), and wherein the at least one first sensor (8) is capable of measuring a first input value in said compartment (5), and at least one second sensor (9) capable of measuring a second input value, wherein said second input value is a temperature value wherein said control unit comprises a matrix of humidity index values, said matrix being deposited in said control unit (10), and wherein said control unit (10) is capable of correlating said input value of said at least one first sensor (8) to a humidity index value from said matrix.