Metal detection system for use with medical waste container
A system for detecting disposal of metallic objects into an opening of a medical waste container, including: an indicator for indicating passage of metallic objects through the opening, a pair of receive coils and a transmit coil spaced therebetween shaped for receiving waste therethrough adjacent to the opening, and a controller in electrical communication with the coils. The controller generates and communicates a transmit signal to the transmit coil, which generates a magnetic field that induces voltage in each of the receive coils, which each generate a receive signal. The controller generates a waveform based on the receive signals with a baseline corresponding to absence of metallic objects, and analyzes the waveform with respect to opposite first and second thresholds. The controller activates the indicator in response to metallic objects passing through the coils when the waveform first exceeds the first threshold and then subsequently exceeds the second threshold.
1. A medical waste collection system for detecting disposal of metallic objects into an opening of a medical waste container, the medical waste collection system comprising:
a plurality of coils including a pair of receive coils and a transmit coil spaced between the receive coils, the plurality of coils being shaped for receiving waste therethrough adjacent to the opening of the medical waste container;
a coil support frame supporting each of the coils, wherein the coil support frame comprises an outer surface and an inner surface, the inner surface defining a passage through the coil support frame for receiving the waste, and the outer surface forming grooves for receiving the plurality of coils; and
a faraday shield wrapped around the coil support frame for shielding the pair of receive coils from external electrical fields.
2. The medical waste collection system of claim 1 , wherein the faraday shield comprises a first faraday arrangement and a second faraday arrangement each wrapped around the coil support frame, the first faraday arrangement having first and second ends and being wrapped around the coil support frame such that the first and second ends are spaced apart from one another, and the second faraday arrangement being insulated from the first faraday arrangement and wrapped around the coil support frame such that the second faraday arrangement encompasses the spaced apart first and second ends of the first faraday arrangement.
3. The medical waste collection system of claim 2 , wherein the first and second faraday arrangements each comprises a strip of non-magnetic electrically conductive material wrapped around the outer and inner surfaces of the coil support frame in an overlapping arrangement.
4. The medical waste collection system of claim 3 , wherein the strip of material is selected from the group consisting of copper and aluminum.
5. The medical waste collection system of claim 2 , wherein the faraday shield further comprises insulating tape wrapped around each of the spaced apart first and second ends for insulating the second faraday arrangement from the first faraday arrangement.
6. The medical waste collection system of claim 1 , further comprising a field shaping arrangement wrapped around the outer surface of the coil support frame such that the field shaping arrangement encompasses the transmit coil for focusing a magnetic field generated by the transmit coil towards the passage defined by the inner surface of the coil support frame.
7. The medical waste collection system of claim 6 , wherein the field shaping arrangement comprises a strip of magnetic field shaping material and a strip of insulating material each wrapped around the outer surface of the coil support frame adjacent the transmit coil.
8. The medical waste collection system of claim 6 , wherein the field shaping arrangement is wrapped around the outer surface of the coil support frame such that the field shaping arrangement is disposed between and vertically spaced from the receive coils.
9. A method of making a medical waste collection system for detecting disposal of metallic objects in an opening of a medical waste container, the method comprising:
providing a coil support frame including an outer surface and in inner surface, the inner surface defining a passage through the coil support frame for receiving waste therethrough, and the outer surface forming grooves;
disposing a plurality of coils including a pair of receive coils and a transmit coil into the grooves such that the transmit coil is spaced between the pair of receive coils; and
wrapping a faraday shield around the coil support frame for shielding the pair of receiving coils from external electrical fields.
10. The method of claim 9 , wherein wrapping the faraday shield around the coil support frame comprises:
wrapping a first faraday arrangement having first and second ends around the coil support frame such that the first and second ends are spaced apart from one another; and
after wrapping the first faraday arrangement, wrapping a second faraday arrangement around the coil support frame such that the second faraday arrangement is insulated from and encompasses the spaced apart first and second ends of the first faraday arrangement.
11. The method of claim 10 , wherein the first and second faraday arrangements each comprises a strip of non-magnetic electrically conductive material, and further comprising:
wrapping the strip of material of the first faraday arrangement around the outer and inner surfaces of the coil support frame in an overlapping arrangement; and
after wrapping the strip of material of the first faraday arrangement, wrapping the strip of material of the second faraday arrangement around the outer and inner surfaces of the coil support frame in an overlapping arrangement such that the strip of material insulated from and encompasses the spaced apart first and second ends of the first faraday arrangement.
12. The method of claim 10 , wherein wrapping the faraday shield around the coil support frame comprises, prior to wrapping the second faraday arrangement around the coil support frame, wrapping insulation tape around each of the spaced apart first and second ends of the first faraday arrangement.
13. The method of claim 9 , further comprising, after wrapping the faraday shield around the coil support frame, wrapping a field shaping arrangement around the outer surface of the coil support frame such that the field shaping arrangement encompasses the transmit coil for focusing a magnetic field generated by the transmit coil towards the passage defined by the inner surface of the coil support frame.
14. The method of claim 13 , wherein wrapping the field shaping arrangement around the outer surface of the coil support frame comprises wrapping a layer of insulation material and a layer of magnetic field shaping material around the outer surface of the coil support frame adjacent the transmit coil.
15. The method of claim 13 , wherein wrapping the field shaping arrangement around the outer surface of the coil support frame adjacent the transmit coil comprises wrapping the field shaping arrangement around the outer surface of the coil support frame such that the field shaping arrangement is disposed between and vertically spaced from the receive coils.
16. A medical waste collection system for detecting disposal of metallic objects into an opening of a medical waste container, the medical waste collection system comprising:
a plurality of coils including a pair of receive coils and a transmit coil spaced between the receive coils, the plurality of coils being shaped for receiving waste therethrough adjacent to the opening of the medical waste container;
a coil support frame supporting each of the coils; and
a faraday shield wrapped around the coil support frame for shielding the pair of receive coils from external electrical fields,
wherein the faraday shield comprises a first faraday arrangement and a second faraday arrangement each wrapped around the coil support frame, the first faraday arrangement having first and second ends and being wrapped around the coil support frame such that the first and second ends are spaced apart from one another, and the second faraday arrangement being insulated from the first faraday arrangement and wrapped around the coil support frame such that the second faraday arrangement encompasses the spaced apart first and second ends of the first faraday arrangement.
17. The medical waste collection system of claim 16 , wherein the coil support frame comprises an outer surface and an inner surface, the inner surface defining a passage through the coil support frame for receiving the waste therethrough, and the first and second faraday arrangements each comprises a strip of non-magnetic electrically conductive material wrapped around the outer and inner surfaces of the coil support frame in an overlapping arrangement.
18. The medical waste collection system of claim 16 , wherein the faraday shield further comprises insulating tape wrapped around each of the spaced apart first and second ends for insulating the second faraday arrangement from the first faraday arrangement.
19. A medical waste collection system for detecting disposal of metallic objects into an opening of a medical waste container, the medical waste collection system comprising:
a plurality of coils including a pair of receive coils and a transmit coil spaced between the receive coils, the plurality of coils being shaped for receiving waste therethrough adjacent to the opening of the medical waste container;
a coil support frame supporting each of the coils; and
a faraday shield wrapped around the coil support frame for shielding the pair of receive coils from external electrical fields,
wherein the coil support frame comprises an outer surface and an inner surface, the inner surface defining a passage through the coil support frame for receiving the waste therethrough, and further comprising a field shaping arrangement wrapped around the outer surface of the coil support frame such that the field shaping arrangement encompasses the transmit coil for focusing a magnetic field generated by the transmit coil towards the passage defined by the inner surface of the coil support frame.
20. The medical waste collection system of claim 19 , wherein the field shaping arrangement comprises a strip of magnetic field shaping material and a strip of insulating material each wrapped around the outer surface of the coil support frame adjacent the transmit coil.