Ultrasonic Hob Boiling Detection for Steam and Fill-Level Control
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Solution Overview
Problem
Existing boiling point detection methods in cooking systems are unreliable due to interference from operating and ambient noises, and are limited by punctiform temperature measurements that fail to differentiate between food and water heat sinks, leading to inaccurate results and complex, expensive constructions.
Innovation Solution
The method employs ultrasonic distance sensor devices positioned above the hob, emitting and receiving sound signals to measure steam development and fill levels, using signal transit time and form to detect boiling points, with the control device adjusting heating output accordingly, independent of noise and vessel type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If structure-borne sound measurement or noise evaluation is used to detect boiling point, then boiling detection can be performed, but measurement precision deteriorates due to interference from operating and ambient noises
Solution Approach 1:
The invention extracts the useful signal (steam generation sound) from the harmful background noise by using a frequency filter that specifically passes frequencies between 1 kHz and 4 kHz, where steam generation sounds are concentrated, while blocking other frequency ranges where operating and ambient noises occur
Solution Approach 2:
The invention applies different evaluation criteria to different frequency ranges, specifically evaluating only the 1-4 kHz frequency band where steam generation sounds are most prominent, rather than treating all frequencies equally, thereby improving measurement precision in the presence of noise
2Reliability
If temperature measurement at the pot base is used to detect boiling point, then temperature can be measured, but measurement precision deteriorates because it cannot differentiate between food and water heat sinks
Solution Approach 1:
The invention replaces the thermal measurement method (temperature sensing at pot base) with an acoustic measurement method (microphone-based sound analysis), allowing detection of boiling through steam generation sounds rather than temperature, thereby avoiding the heat sink differentiation problem
Solution Approach 2:
The invention introduces sound waves as an intermediary medium to detect boiling indirectly through steam generation sounds, rather than directly measuring temperature at the pot base, enabling differentiation between boiling states without being affected by heat sink variations
3Reliability
If ultrasonic measuring sections are arranged below the hob device to perform boiling point detection, then detection can be performed, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The invention makes the microphone serve multiple functions: it is used both for voice recognition/control and for steam generation sound analysis, eliminating the need for separate ultrasonic sensors below the hob and thereby reducing device complexity and manufacturing costs
Solution Approach 2:
The invention merges the voice recognition function and boiling detection function into a single microphone system, combining previously separate functions into one component, which simplifies the overall system construction and reduces costs
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 provides precise and noise-independent boiling point detection, allowing for efficient and accurate monitoring of steam and fill levels, reducing heating power when boiling is detected, and preventing over-boiling, with a simpler and less expensive system design.
Implementation Method 1
The ultrasonic distance sensor devices each comprise at least one sound source and at least one sound receiver. At least one sound signal, which is detected by the sound receivers, is output from the sound sources of the ultrasonic distance sensor devices.
Implementation Method 2
the sound source and sound receiver being positioned on opposite sides of the cooking vessel, in particular directly on or in the cooking vessel
Implementation Method 3
the evaluation device is suitable and designed to draw conclusions about the steam development and/or the fill level of a cooking vessel standing on the cooking zone via the duration of the sound signal and/or via the form of the received sound signal
Data Source
Figure 1
AI summary
Method for operating a cooking system (1) comprising an ultrasonic distance sensor device (100) with a sound source (101) and a sound receiver (102), an evaluation device (200) and a hob device (300) with a cooking zone (301) with a heating device ( 302) and with a control device (303) for controlling the heating device (302). The ultrasonic distance sensor device (100) is arranged in sections above the hob device (300) and is operatively connected to the control device (303) of the hob device (300) via the evaluation device (200). A sound signal (103) is emitted by the sound source (101) and is detected by the sound receiver (102), with the evaluation device (200) being suitable and designed to use the propagation time of the sound signal (103) and/or the form of the to draw conclusions about the steam development and/or the fill level of a cooking vessel (304) standing on the cooking zone (301) from the received sound signal. The control device (303) takes into account the evaluation of the sound signals (103) when controlling the heating device (302).