Inductively Coupled Sensor Circuit for Sanitary Inflow Detection
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Solution Overview
Problem
Existing sanitary appliances face challenges in accurately sensing the electrical conductivity of aqueous solutions, particularly at locations remote from the flow surface, and distinguishing between liquid and solid matter inflows, due to sensitivity issues and contamination by dirt.
Innovation Solution
A sensor circuit comprising a resonant tank circuit with a primary circuit and a secondary circuit, using inductive coupling and capacitive sensing, which amplifies resonance to distinguish between liquid and solid matter based on conductivity variations, with electrodes positioned to avoid direct contact with the aqueous solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitive sensor is used to sense inflow of urine in a siphon, then the sensing becomes less sensitive to dirt and contamination, but the sensor has limited suitability for locations remote from the flow surface and dirt may still adhere to surfaces causing capacitance shifts
Solution Approach 1:
The patent replaces direct contact capacitive sensing with inductive coupling between primary and secondary circuits. The secondary circuit includes capacitive sensors that sense conductivity variations in the aqueous solution without requiring direct contact, thereby eliminating dirt adhesion issues while maintaining measurement precision through inductive signal transmission.
Solution Approach 2:
The patent introduces an intermediate inductive coupling mechanism between the primary control circuit and the secondary sensing circuit. This intermediary allows the capacitive sensors to be positioned remote from the flow surface while still accurately sensing conductivity variations through the magnetic field coupling, resolving both the reliability and precision requirements.
2Reliability
If electrodes are positioned to avoid direct contact with the aqueous solution, then interference from dirt and contamination is reduced, but the sensing of conductivity variations becomes more challenging
Solution Approach 1:
The patent replaces direct electrical contact measurement with inductive coupling measurement. The primary circuit generates a magnetic field that couples with the secondary circuit containing capacitive sensors, allowing conductivity detection through field interaction rather than direct electrode contact, thus maintaining reliability while enabling indirect measurement.
Solution Approach 2:
The patent changes the measurement parameter from direct capacitive coupling to inductive coupling with capacitive sensing. By using the relationship between inductance, capacitance, and conductivity in the secondary circuit, the system can detect conductivity variations through changes in the resonant frequency or impedance of the coupled circuits without requiring direct electrode contact.
3Reliability
If a resonant circuit is used to sense inflow of urine at the flow surface, then the sensing becomes less sensitive to dirt and contamination, but the sensor is not suitable for locations remote from the receptacle
Solution Approach 1:
The patent uses inductive coupling as an intermediary to extend the sensing capability from the flow surface to remote locations. The primary circuit can be positioned at the flow surface where it is less affected by dirt, while the secondary circuit with capacitive sensors can be positioned remotely in the siphon or other locations, with both circuits communicating through magnetic field coupling.
Solution Approach 2:
The patent divides the sensing system into two separate circuits: a primary circuit that can be positioned at the flow surface and a secondary circuit that can be positioned remotely. This segmentation allows each circuit to be optimized for its specific location while maintaining functional connectivity through inductive coupling, thereby achieving both reliability and location adaptability.
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 sensor circuit provides reliable and accurate sensing of conductivity and inflow type, reducing interference from dirt and contamination, enabling effective control of flushing and cleaning protocols in sanitary appliances.
Implementation Method 1
A sensor circuit comprising a resonant tank circuit with a primary circuit and a secondary circuit, using inductive coupling and capacitive sensing
Implementation Method 2
which amplifies resonance to distinguish between liquid and solid matter based on conductivity variations
Implementation Method 3
The sensor circuit provides reliable and accurate sensing of conductivity and inflow type
Implementation Method 4
for sensing of an electrical conductivity of an aqueous solution or variation thereof
Data Source
Figure 1~2
Figure 3~5
Figure 4a~4c
AI summary
The sanitary appliance (400) comprises a receptacle (410) and a tube (420) provided with a tube wall (401, 402) and configured to contain - in use -an aqueous solution (1000) and a sensor circuit (105) for sensing inflow of matter into the sanitary appliance (400), wherein the sensor circuit (105) comprises a primary circuit and a secondary circuit that are mutually inductively coupled, wherein the inductively coupled secondary circuit includes a capacitive sensor comprising a first and a second electrode (101, 102), each of which are configured to be in use at least partially (101, 192) in contact with the aqueous solution (1000), which constitutes a medium of the capacitive sensor.