| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an economical needle detector detecting a needle mingled with an object to be detected in food/sewn products. SOLUTION: Search coils 20 consists of a pair of two pairs of so-called opposedly arranged transmission and reception search coils whose magnetic paths of detecting excitation magnetic flux inside a tunnel passage 4 cross the conveying direction inside the tunnel 4 at right angles and transmission and reception coaxial arrangement type search soils whose magnetic paths are coaxial with the conveying direction, or consists of a pair of vertical type search coils formed by combining respective pairs of the different search coil. These search coils are arranged in the truncated chevron shape or inverted truncated chevron shape at fixed inclinations to a conveying machine passing though and using the tunnel passage. When the arrangement attitude of the pair of search coils is changed, the detecting excitation magnetic flux inside the tunnel is relatively complemented or changed, so that problems often occurring in a conventional machine such as unevenness of detection sensitivity, detection impossibility in an extreme case, to a migrated attitude of a needle type object to be detected in a tested body can be solved in this needle detector.</p> |
