Printed Coil Sensor for Metal Particle Detection
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Solution Overview
Problem
Conventional sensor apparatus for detecting metal particles in fluids, such as lubricating oil or grease, face challenges in reproducibility, cost-effectiveness, and sensitivity due to the use of mechanically wound solenoidal coils, which are time-consuming, labor-intensive, and prone to mechanical imperfections.
Innovation Solution
A sensor apparatus utilizing a printed coil on a printed circuit board (PCB) substrate, which is more reproducible, cost-effective, and mechanically stable, allowing for improved sensitivity and resolution, especially when detecting individual metal particles in dynamic samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanically wound solenoidal coils are used for metal particle detection, then the sensor can detect metal particles in fluids, but the manufacturing process becomes time-consuming, labor-intensive, and prone to mechanical imperfections
Solution Approach 1:
The patent replaces the mechanical winding process with a printed circuit board (PCB) technology. The coil is formed by printing conductive material patterns on a PCB substrate, eliminating the need for manual or automated mechanical winding. This substitution maintains the electromagnetic detection function while achieving precise geometric control, high reproducibility, and efficient manufacturing through standard PCB fabrication processes.
2Strength
If mechanically wound solenoidal coils are used, then the sensor structure can be formed, but mechanical imperfections and variations occur affecting sensitivity and resolution
Solution Approach 1:
The mechanical winding process is replaced with PCB printing technology, which uses photolithography and other precise manufacturing methods to deposit conductive material in exact patterns. This ensures uniform coil geometry, consistent turn spacing, and precise dimensional control that cannot be achieved through mechanical winding, thereby improving both structural integrity and geometric precision.
Solution Approach 2:
The patent changes the manufacturing parameters from mechanical processes to chemical and thermal processes used in PCB fabrication. The conductive traces are formed through controlled deposition, etching, and lamination processes that offer tighter process control and repeatability, resulting in more consistent coil parameters across production batches.
3Ease of manufacture
If conventional wound coils are used, then the sensor can be manufactured, but the process is costly and time-consuming
Solution Approach 1:
The time-intensive mechanical winding operation is replaced with PCB manufacturing processes that can produce multiple coils simultaneously in a single production run. The printed coil structure eliminates sequential winding steps and allows for parallel fabrication, dramatically reducing manufacturing cycle time while maintaining quality standards.
Solution Approach 2:
The PCB substrate serves multiple functions: it provides the structural base for the coil, acts as an electrical insulator, offers mounting surfaces for other components, and enables integration with electronic circuitry. This multi-functionality consolidates what would otherwise require separate components and assembly steps, reducing both time and cost.
4Reliability
If mechanically wound coils are used, then the sensor can detect metal particles, but labor intensity increases
Solution Approach 1:
The manual or automated mechanical winding operation is completely replaced with PCB printing processes that are performed by automated manufacturing equipment. The conductive patterns are deposited, etched, and cured through automated sequences, eliminating the need for operators to perform repetitive winding tasks, thereby reducing labor intensity while maintaining detection reliability.
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 printed coil sensor apparatus provides reliable and sensitive detection of metal particles, offering comparable or higher sensitivity than conventional wound coils, with improved manufacturing efficiency and reduced variation, making it suitable for monitoring metal wear debris in engines and gearboxes.
Implementation Method 1
An alternating magnetic field induces eddy currents in any conducting material, and will also be affected by the magnetic properties of the material. By detecting a resulting change in the magnetic field it is therefore possible to detect the presence of metals.
Implementation Method 2
The basic concept is that an alternating magnetic field induces eddy currents in any conducting material, and will also be affected by the magnetic properties of the material.
Implementation Method 3
metals having a spontaneous net magnetic moment, such as iron, nickel and cobalt, are classified as ferromagnetic. Ferromagnetic materials may in turn be classified as 'soft' or 'hard'. Soft ferromagnets have a low coercivity, i.e. the net magnetisation can easily be reversed e.g. by changing the direction of an applied magnetic field.
Data Source
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AI summary
A sensor apparatus 70 for use in determining a count of individual metal particles with respect to volume for a dynamic sample provided by a volume of fluid flowing through a sensing region of the apparatus between first and second times. The sensor apparatus comprises magnetic field generating means for generating a magnetic field for application to a sample in the sensing region and sensing means comprising one or more electrically conductive coils for sensing the result of interaction between the generated magnetic field and a dynamic sample provided by a volume of fluid flowing through the sensing region between first and second times. The sensor apparatus also includes a flow sensor 72 for determining data indicative of a rate of fluid flow through the sensing region. The sensed result of the interaction and the data indicative of the rate of fluid flow through the sensing region determined by the flow sensor are thus usable together in determining a count of individual metal particles with respect to volume for the dynamic sample. The sensor apparatus is configured such that the sensing region receives only a portion of the fluid flow of a system with respect to which the sensor apparatus is mounted to provide the dynamic sample in the region of the sensor apparatus.