Non-Mechanical Flow Sensor for Leak Detection in Household Appliances
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Solution Overview
Problem
Existing anti-flooding safety devices for liquid-conducting household appliances face challenges with precision and reliability, particularly due to sticking issues with impeller flow sensors caused by water impurities and inevitable wear, which affects detection accuracy and sensitivity, especially for minor leaks.
Innovation Solution
A safety device incorporating a non-mechanical flow sensor with electrical detection elements and a leakage sensor, utilizing electromagnetic-induction principles to measure flow-rate and detect leaks without moving parts, enhancing precision and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an impeller flow sensor is used to measure flow-rate, then the device can detect water flow, but the sensor suffers from sticking issues due to water impurities and wear, reducing reliability
Solution Approach 1:
The patent replaces the mechanical impeller flow sensor with a magnetic field-based flow sensor that has no moving parts. The new sensor uses a magnet mounted on a rotating element (such as a float or turbine) that rotates with water flow, and this rotation is detected by a stationary magnetic sensor (such as a Hall effect sensor or reed switch). This substitution eliminates mechanical wear and sticking issues while maintaining flow measurement capability, directly resolving the reliability-precision contradiction.
2Reliability
If a mechanical valve arrangement is used to close the duct, then the valve can stop water flow, but the mechanical components are subject to wear and failure over time
Solution Approach 1:
The patent replaces the mechanical valve arrangement with an electromagnetic valve (solenoid valve) that uses an electromagnetic field to control water flow. The electromagnetic valve has no moving parts that contact each other during operation, eliminating mechanical wear while maintaining the ability to open and close the water duct. This resolves the contradiction between reliability and ease of operation by providing a simple electrical control interface with enhanced durability.
3Loss of information
If the gap between inner and outer pipes is open at the distal end to allow leakage collection, then leakage water can be detected, but it is impossible to know immediately whether the leakage is from the safety device or the appliance
Solution Approach 1:
The patent segments the detection system into two separate detection zones: one for detecting leakage within the safety device (using the gap between inner and outer pipes) and another for detecting leakage from the appliance (using a separate sensor in the collection tray). By providing separate detection pathways and signals for each zone, the system can identify the source of leakage without requiring complex analysis, resolving the contradiction between information completeness and system simplicity.
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
The solution provides improved detection accuracy and reliability for flow-rates and leaks, including minor ones, allowing for quicker identification of leak sources within appliances or the safety device itself, reducing false positives and improving long-term performance.
Implementation Method 1
utilizing electromagnetic-induction principles to measure flow-rate
Implementation Method 2
with electrical detection elements... detecting any possible leakage water that flows into the gap between the two pipes
Data Source
AI summary
A safety device against leaks of liquid for a liquid-conducting household appliance comprises a valve arrangement that can be electrically switched between a closing position and an opening position, to prevent or enable, respectively, a flow of liquid from a liquid-supply source to the household appliance. The device further comprises:—a first pipe (13) impermeable to liquid, for the flow of liquid,—at least one hydraulic unit (12), having a duct for the liquid (30),—a flow sensor in the at least one hydraulic unit (12). The first pipe (13) is connected in fluid communication with the duct (30) and extends longitudinally at least in part within a second pipe (14) that is impermeable to liquid, in such a way that defined between at least part of the first pipe (13) and of the second pipe (14) is a gap (G) having a proximal end and a distal end. The at least one hydraulic unit (12) has a respective hydraulic body (16) that defines the duct (30). The flow sensor is a non-mechanical flow sensor that includes at least two electrical detection elements (42) within the duct (30).