Multi-Frequency Metal Detector Coil with Dual Receiving Coils
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Solution Overview
Problem
Existing multi-frequency metal detectors face challenges in achieving high sensitivity for small metal targets while maintaining optimal depth for large targets, especially when operating with large coils on heavy or moist soils, due to parasitic signals from the soil and electromagnetic fields.
Innovation Solution
A search coil design featuring a main receiving coil and an additional smaller receiving coil, both in inductive balance with a transmission coil, allows simultaneous operation at high and low frequencies, enhancing sensitivity for small targets and depth for large targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large search coil is used for low frequency operation to detect large metal targets at depth, then detection depth is improved, but sensitivity to small metal targets deteriorates
Solution Approach 1:
The search coil system is segmented into multiple receiving coils of different sizes (first receiving coil and second receiving coil). The second receiving coil is specifically designed with smaller dimensions to detect small metal targets, while the first receiving coil handles large metal targets. This segmentation allows each coil to be optimized for its specific detection task, resolving the contradiction between coil size and sensitivity to small targets.
2Measurement precision
If a small search coil is used for high frequency operation to detect small metal targets with high sensitivity, then sensitivity to small metal targets is improved, but detection depth for large metal targets deteriorates
Solution Approach 1:
The system segments the receiving function into multiple coils with different size characteristics. The first receiving coil, being larger, is optimized for deep detection of large metal targets at high frequencies, while the second receiving coil, being smaller, provides high sensitivity for small metal targets. This segmentation resolves the contradiction between coil size and detection depth.
3Device complexity
If a single receiving coil is used to receive all frequencies from the transmitting coil, then device complexity is reduced, but detection performance across different frequencies deteriorates
Solution Approach 1:
The system implements multi-functionality by equipping the search coil with multiple receiving coils that can handle different frequency ranges and detection requirements simultaneously. The first receiving coil and second receiving coil work together to provide universal detection capability across both low and high frequencies, for both small and large metal targets, resolving the contradiction between simplicity and versatility.
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 dual-coil design effectively combines the advantages of small and large coils, providing high sensitivity and optimal depth detection for both small and large metal objects.
Implementation Method 1
The coil is a component of a device for detecting metal objects-metal detector... consisting of a housing in which one transmitter and one receiver coil are placed... inductive balance between the transmitting and the receiving coil
Data Source
AI summary
The invention relates to a coil for multi-frequency metal detector, which is used to detect metal objects, located deep in the ground or other places, and has applications in the fields of archaeology, geology, construction, military and police practice, etc. The coil works equally effectively at both high and low frequencies, in the range of 500 Hz-100 KHz. As a result of the joint action of the three coils housed in one housing, the coil multi-frequency detector has a high sensitivity to small metal targets and optimal depth operation for the detection of large metal targets. It consists of housing (1), in which mutually balanced transmitter (2), main receiver (3) and additional receiver (4) coils are placed. The transmitting coil (2) and the main receiving coil (3), which are made in the shape of the Latin letter D, with the radius of curvature identical to the outer surface of the housing (1).