Magnetic Field Detector for Automatic Kitchen Extractor Switching
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Solution Overview
Problem
Existing methods for operating extractor devices in kitchens require complex electrical connections and specialist knowledge, as they need to detect current flow in hob electrical cables, which is challenging due to twisted conductors canceling out magnetic fields.
Innovation Solution
A three-axis magnetic field sensor is positioned around the electrical cable to detect stray fields when current flows, transmitting signals to the extractor device's control for automatic switching on and off, allowing for simple installation without altering the electrical installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a detector is installed around the electrical cable to detect current flow, then the extractor device can automatically switch on and off, but the twisted conductors cancel out magnetic fields making detection difficult
Solution Approach 1:
The patent positions the magnetic field sensor at a specific location where stray magnetic fields are detectable despite the twisted conductor configuration. The sensor is placed in proximity to the cable insulation layer, allowing detection of local magnetic field variations caused by current flow changes, while the twisted conductors' fields cancel out at greater distances.
Solution Approach 2:
The patent uses the cable insulation layer as an intermediary medium to position the sensor. The sensor is mounted on the insulation layer, which provides a stable mounting surface while maintaining close proximity to the conductors for effective magnetic field detection, bridging the gap between the conductors and the sensor.
2Ease of operation
If electrical connections are made to detect current flow in hob electrical cables, then switching control is achieved, but complex electrical connections and specialist knowledge are required
Solution Approach 1:
The patent replaces the need for electrical connections and circuit modifications with a magnetic field detection approach. Instead of mechanically connecting to electrical conductors, the system uses a non-contact magnetic field sensor that detects current flow through the magnetic field generated by the current, eliminating the need for electrical installation modifications.
Solution Approach 2:
The detector automatically detects current flow changes in the electrical cable without requiring manual intervention or specialist knowledge for installation. The system self-configures by detecting the magnetic field signature of the cable, automatically establishing the linkage between hob operation and extractor hood control.
3Use of energy by moving object
If the extractor device switches off immediately with the hob, then energy consumption is reduced, but residual cooking odors remain
Solution Approach 1:
The system performs preliminary action by detecting current flow changes and anticipating the end of cooking activity. When the hob is switched off, the detector recognizes the current drop and triggers the extractor hood to continue running for a predetermined delay period, proactively addressing residual odors before they become problematic.
Solution Approach 2:
The system uses feedback from the magnetic field sensor to monitor hob operation status. The sensor continuously detects current flow, and when current drops indicating hob shutdown, this feedback triggers the delayed shutdown sequence of the extractor hood, creating a closed-loop control system that responds to actual cooking activity.
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
Enables easy, non-specialist installation of extractor devices that automatically sync with hob switching, including delayed switching off to eliminate residual cooking odors, with low energy consumption and reliable detection of current flow.
Implementation Method 1
the detector comprises a three-axis magnetic field sensor, which is designed such that, in the mounted state, it is positioned at least partially around the electrical cable of the kitchen appliance
Data Source
Figure 1
AI summary
In a method for operating a ventilation system for a kitchen appliance, preferably for a cooktop with multiple heating elements, the heating element of the kitchen appliance is supplied with electricity via an electrical cable (11) connected to it. At least one detector (15) is installed on the electrical cable (11) of the kitchen appliance in such a way that the detector (15) can detect when a current flow in the electrical cable (11) of the kitchen appliance is switched on and/or off. This is transmitted by the detector (15) to the control unit of the ventilation system, which can be switched on and/or off depending on the detected current flow in the electrical cable (11). This can be achieved with a very simple installation without any expert intervention, even retrofitted to kitchen appliances that are already installed and in operation.