Electricity: measuring and testing – Magnetic – With compensation for test variable
Patent
1997-03-17
1999-04-20
Snow, Walter E.
Electricity: measuring and testing
Magnetic
With compensation for test variable
324243, G01N 2772, G01R 3312
Patent
active
058960317
ABSTRACT:
A metal detector (1) having an oscillator coil (10) which radiates an electromagnetic field in the vicinity of an article to be tested. The field is detected by a primary set of receiver coils (15) which are in close proximity to the oscillator coil (10), as well as by a secondary set of receiver coils (18) located relatively more distant from the oscillator coil. Moving or vibrating metal external to the detector cavity (7) surrounded by the coils (15, 18) will produce a modulated waveform (48) in the primary coils (15) which is similar in period to the modulated waveform (56) produced by the secondary coils (18), while metal passing through the detector cavity (7) will produce a waveform (24) from the primary coils (15) which has a period which differs from the period of the waveform (31) produced by the secondary coils (18). By inverting the secondary coil output signal (42) and adding the inverted signal to the output signal (46) produced by the primary coils (15), a composite signal (68) is produced in which the effect of vibrating or moving metal external to the detector cavity (7) is reduced or eliminated.
REFERENCES:
patent: 4613815 (1986-09-01), Christel, Jr.
patent: 5572121 (1996-11-01), Beswick
Johnson David George
Snow Walter E.
Thermo Sentron, Inc.
LandOfFree
Quad coil vibration cancelling metal detector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Quad coil vibration cancelling metal detector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quad coil vibration cancelling metal detector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2250241