Resonance Sensor for Urine Flow Detection in Sanitary Appliances
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Solution Overview
Problem
Existing sanitary appliances with capacitive sensors face challenges in accurately distinguishing urine flow from background capacitance due to adherence of urine constituents to the receptacle surface, leading to reduced sensitivity and difficulty in identifying dirt layers.
Innovation Solution
The use of sensors that measure the quality factor, rather than capacitance, to detect urine flow and dirt layers by applying an excitation frequency close to the resonance frequency, allowing for differential sensing and identification of changes in resonance frequency due to dirt or urine presence, with multiple sensors providing enhanced accuracy and application in both urine detection and film detection modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive sensor is used to detect urine flow, then urine flow can be detected, but the sensor sensitivity is reduced due to adherence of urine constituents to the receptacle surface forming a background capacitance
Solution Approach 1:
The patent applies dynamic sensing by measuring the change in capacitance over time rather than a static capacitance value. The sensor detects urine flow by identifying transient changes in capacitance background, allowing differentiation between temporary urine flow events and persistent background capacitance formed by adhered urine constituents.
Solution Approach 2:
The system performs preliminary measurements to establish a baseline capacitance background before detecting urine flow. By continuously monitoring and updating the background capacitance profile, the system prepares reference data that enables accurate detection of urine flow events against the established background, compensating for adhered residues.
2Reliability
If cleaning liquid is frequently applied to remove dirt layers, then hygiene is maintained, but water consumption increases
Solution Approach 1:
The sensor provides continuous feedback on the actual state of the receptacle surface by detecting capacitance changes associated with dirt layer formation. This feedback enables the cleaning system to operate only when necessary, triggering cleaning operations based on real-time contamination detection rather than following fixed schedules, thereby optimizing water consumption while maintaining hygiene standards.
Solution Approach 2:
The system enables self-monitoring of the receptacle condition through the capacitive sensor, which automatically detects when dirt layers require removal. This self-service capability allows the system to autonomously determine cleaning needs without manual intervention or predetermined schedules, activating cleaning only when the sensor detects contamination levels that require attention.
3Measurement precision
If multiple sensors are used to improve detection accuracy, then measurement precision increases, but device complexity increases
Solution Approach 1:
The detection system is segmented into functional components: a capacitive sensor element, a signal processing unit, and a control unit. This segmentation allows the complex detection task to be divided into manageable parts, where the sensor captures raw capacitance data, the processing unit analyzes changes against background levels, and the control unit executes appropriate responses, reducing overall system complexity through modular functional division.
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 enables reliable detection of urine flow and dirt layers, optimizing flushing schedules and cleaning operations while minimizing water consumption and maintaining hygiene standards, with potential applications beyond urinals to other appliances.
Implementation Method 1
by sensing in the area of resonance, a relative difference in sensed voltage between air and other media such as urine and water, remains unaltered to a significant extent
Implementation Method 2
The capacitive sensor is located on a rear side of the receptacle. Flow of urine in the receptacle at a location approximately opposite to the capacitive sensor may be detected as a change in capacitance
Implementation Method 3
The receptacle typically is a body of ceramic, dielectric material. The urine flow thus constitutes only an addition to the background capacitance
Data Source
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AI summary
The sanitary appliance comprising a receptacle provided with a flow surface and further comprising at least one sensor for sensing flow of urine (a physiological solution) located at a distance from the flow surface of the receptacle, characterised in that the sensor comprises a resonance circuit. Urine flow may be identified at the flow surface in that: (1) a first voltage is provided to a resonance circuit to be modified into a second voltage; (2) the second voltage is sensed and (3) the second voltage is compared with a reference value for identification of urine flow. Furthermore a dirt layer with a thickness at the flow surface may be identified.