Electromagnetic sensor with buffered power supply and flowmeter comprising this sensor
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Solution Overview
Problem
Existing flow meters in home appliances like dishwashers and washing machines face issues with mechanical wear and contact bounce in reed contacts, which require additional filtering and processing, and cannot be easily replaced by Hall sensor chips due to power supply limitations.
Innovation Solution
A magneto-sensitive electronic unit with three terminals, including a power supply terminal, is integrated into the flow meter, allowing for interchangeable operation with reed contacts without modifying the evaluation circuit, using a magnetic sensor element and electronic switching element to generate digital signals based on magnetic field strength, and a buffered power supply to maintain stable voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If reed contacts are used in flow meters, then the device can be simple and cost-effective, but mechanical wear and contact bounce occur leading to reduced reliability
Solution Approach 1:
The patent replaces the mechanical reed contact system with an electronic Hall sensor system. The Hall sensor (magnetic field sensor) detects the position of the impeller magnetically without mechanical contact, eliminating wear and contact bounce while maintaining the flow measurement function. The electronic switching element (transistor) replaces the mechanical switching action of the reed contact.
2Reliability
If Hall sensor chips are used to replace reed contacts, then mechanical wear is eliminated, but additional power supply terminals and circuit modifications are required
Solution Approach 1:
The patent designs the Hall sensor module to be universally compatible with existing reed contact interfaces. The module uses a single digital input terminal that can directly replace reed contacts in existing circuits without modification. The power supply is integrated into the module itself, allowing it to function as both a sensor and a power source for the electronic switching element.
Solution Approach 2:
The patent combines multiple functions into a single integrated module: the Hall sensor, the electronic switching element (transistor), and the power supply buffer are merged into one component that replaces the reed contact. This integration eliminates the need for separate power supply terminals and circuit modifications, as the module interfaces with the existing single digital input terminal.
3Reliability
If electronic switching elements are used instead of reed contacts, then contact bounce is eliminated, but power supply stability becomes critical
Solution Approach 1:
The patent implements a power supply buffer (capacitor) that is pre-charged during periods when the impeller is not blocking the magnetic field. This preliminary energy storage ensures that when the impeller blocks the field and the transistor switches on, the power supply remains stable and continuous, preventing voltage drops that could cause unreliable switching.
Solution Approach 2:
The power supply buffer acts as an energy cushion that compensates for power supply interruptions or voltage drops. By storing energy in advance, the buffer ensures continuous and stable power supply to the electronic switching element, protecting against power supply instability and ensuring reliable operation of the digital signal output.
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 solution provides a reliable and cost-effective replacement for reed contacts, eliminating mechanical wear and contact bounce issues, and enabling seamless integration with existing control units without additional complexity or cost, ensuring accurate fluid flow measurement.
Implementation Method 1
a magnetic sensor element (120) having three terminals, namely two output terminals (126, 127) as well as a power supply terminal (128), and an electronic switching element (124) connected to the two output terminals (126, 127)
Implementation Method 2
a buffered power supply unit (130) which has a first terminal (132) connected to the reference terminal (116) and a second terminal (134) connected to the signal terminal (114) of the magneto-sensitive unit (100), as well as a third terminal (136) connected to the power supply terminal (128) of the magnetic sensor element (120), wherein the buffered power supply unit (130) is configured to generate a continuous (buffered) auxiliary voltage (Va) from the digital voltage signal (Vd)
Data Source
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AI summary
A flow meter for a home appliance, in particular a dishwasher or a washing machine, the flow meter comprising a control unit (10) having a first power supply terminal (16), a second power supply terminal (18) and a digital input terminal (14) which is connected to the second power supply terminal (18) via a limiting element (12), wherein the digital input terminal (14) is configured to receive digital voltage signals; a movable element which is moved by a flow of a fluid and which comprises at least one movable magnetic element; and a magneto-sensitive unit (100) which is arranged to detect a magnetic field or flux applied by the movable magnetic element, and which comprises a signal terminal (114) configured to be connected to the digital input terminal (14) of the control unit (10) and a reference terminal (116) configured to be connected to the first power supply terminal (16) of the control unit (10); wherein the magneto-sensitive unit (100) comprises a magnetic sensor element (120) having two output terminals (126, 127) connected to the signal terminal (114) and the reference terminal (116), respectively, of the magneto-sensitive unit (100) and a power supply terminal (128); and a buffered power supply unit (130) connected to the signal terminal (114) and the reference terminal (116) of the magneto-sensitive unit (100), and configured to provide a continuous auxiliary voltage (Va) at the power supply terminal (128) of the magnetic sensor element (120).