Metal detector coil configuration to eliminate orientation effect
A system for metal detection comprises a single aperture comprising two or more sets of detection coils that surround the perimeter of the aperture. A flow path of materials passes through the aperture. Each set of detection coils comprises a transmitter and two receiver coils, with the transmitter coil located between the two receiver coils. Each set of detection coils is at a different angle relative to the flow path.
1. A system for metal detection comprising:
a single aperture comprising two or more sets of detection coils that surround the perimeter of said aperture wherein each said detection coil defines a detection plane within the aperture;
a flow path of materials that passes through said aperture;
each said set of detection coils comprises a transmitter coil and two receiver coils, with said transmitter coil located between said two receiver coils; and
each set of said detection coils is at a different angle relative to said flow path such that said flow path is subjected to each of said detection planes simultaneously.
2. The system for metal detection of claim 1 wherein one set of detection coils is at an angle of 45 degrees relative to said flow path.
3. The system for metal detection of claim 1 wherein one set of detection coils is at an angle of 135 degrees relative to said flow path.
4. The system for metal detection of claim 1 further comprising said flow path is one of a conveyor belt, a liquid line, or free-falling material.
5. The system for metal detection of claim 1 wherein said aperture is circular or a polygon.
6. The system for metal detection of claim 1 wherein said aperture comprises three sets of said detection coils that surround the perimeter of said aperture.
7. The system for metal detection of claim 1 wherein said detection coils operate in the range of 1 kHz to 1 MHz.
8. The system for metal detection of claim 1 wherein each said set of detection coils operates in a different detection frequency.
9. The system for metal detection of claim 1 wherein each said set of detection coils operates in the same detection frequency.