Flowmeter comprising an electronic magnetic sensor with buffered power supply
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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 complex filtering and can lead to failure over time, and replacing them with Hall sensors is not straightforward due to power supply and signal level compatibility.
Innovation Solution
A flow meter design incorporating a two-lead magneto-sensitive unit with a magnetic sensor element and electronic switching element, such as a Hall effect sensor or magneto-resistive sensor, connected to a buffered power supply unit, allowing it to generate digital signals without additional complexity to the control unit, and optionally including adapting units to maintain stable states or oscillations for fluid flow detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reed contact is used in the flow meter, then the device complexity is low and manufacturing is simple, but mechanical wear and contact bounce occur leading to reduced reliability
Solution Approach 1:
The patent replaces the mechanical reed contact with an electronic Hall effect sensor that detects magnetic field changes electronically. This substitution eliminates mechanical wear and contact bounce while maintaining the flow detection function, directly resolving the contradiction between reliability and device complexity.
2Reliability
If a Hall sensor is used to replace the reed contact, then mechanical wear is eliminated, but additional power supply terminals and signal level adaptation are required increasing device complexity
Solution Approach 1:
The Hall sensor is designed to operate with a single power supply terminal that serves multiple functions: providing power to the sensor and establishing the digital signal level. This multi-functionality approach eliminates the need for separate power supply terminals and signal level adaptation circuits, reducing device complexity while maintaining reliability.
Solution Approach 2:
The patent combines the power supply function and digital signal output function into a single terminal connection. By merging these functions, the design eliminates additional terminals and adaptation circuits that would otherwise be required, thereby reducing device complexity while maintaining the reliability benefits of the Hall sensor.
3Adaptability or versatility
If a reed contact is used, then compatibility with existing control units is maintained, but contact bounce generates false pulses requiring filtering
Solution Approach 1:
The electronic Hall sensor replaces the mechanical reed contact, eliminating contact bounce entirely. The Hall sensor provides clean digital signals without the mechanical vibrations that cause false pulses, thereby improving measurement precision while maintaining compatibility with existing control units through the same digital output interface.
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, reducing mechanical wear and contact bounce, while maintaining compatibility with existing control units and allowing for interchangeable components, thus enhancing the longevity and accuracy of fluid flow measurement.
Implementation Method 1
A two-lead magneto-sensitive unit 100... comprises a magnetic sensor element 120... which is arranged to detect a magnetic field or flux applied by the movable magnetic element
Implementation Method 2
such as a Hall effect sensor or magneto-resistive sensor
Implementation Method 3
a buffered power supply unit 130... configured to generate a continuous auxiliary voltage from the signal terminal and the reference terminal of the magneto-sensitive unit and to provide the continuous auxiliary voltage at the power supply terminal of the magnetic sensor element
Data Source
AI summary
A flow meter for a home appliance, in particular a dishwasher or a washing machine, the flow meter comprising a control unit having a first power supply terminal, a second power supply terminal and a digital input terminal which is connected to the second power supply terminal via a limiting element; a movable element which is moved by a flow of a fluid and which comprises at least one movable magnetic element; and a two-lead magneto-sensitive unit which comprises a signal terminal connected to the digital input terminal of the control unit and a reference terminal connected to the first power supply terminal of the control unit; wherein the magneto-sensitive unit comprises a magnetic sensor element having two output terminals connected to the signal terminal and the reference terminal, and a power supply terminal; and a buffered power supply unit configured to generate a continuous auxiliary voltage from the signal terminal and the reference terminal of the magneto-sensitive unit and to provide the continuous auxiliary voltage at the power supply terminal of the magnetic sensor element.