PURPOSE: To detect the metal passing through accurately by arranging one square coil on each of top and bottom surfaces surrounding a path and two square coils on each of right and left surface so that current flows in the opposite direction on the boundary of the top and bottom surfaces and right and left surfaces and in the same direction on the boundary of the top and bottom coils in the right and left surfaces.
CONSTITUTION: A total of six coils 1W6 are arranged on top and bottom surfaces and right and left surfaces (in total 4 surfaces) surrounding a path 10. Each one of coils 1 and 4 is disposed on the top and bottom surfaces and each two of coils 2, 3 and 5, 6 on the right and left surfaces. The coils 1W6 are all square coils wound on a square coil frame. Exciting current flows through the coils 1W 6 in the direction as illustrated so that the distribution of the magnetic field turns in various directions within the horizontal surface other than the central part, changing in a three-dimensional direction. Therefore, as metal passes, it is sequentially given a magnetic field from various directions thereby enabling the detection of the metal regardless of the attitude of a sheet-shaped metal. As the strength of the magnetic field enhances at the central part, the metal can be detected even if it is somewhat unfavorable in the shape and the attitude thereof.
KOTANI FUMIO
TAKAHASHI YOSHIMASA
YAMADA YASUHARU
SHIMADZU CORP
| JPS49104662A | 1974-10-03 |
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