MAGNETIC BODY DETECTOR

• Main Author: MASUBUCHI SHINICHI
• Format: Patent
• Language: English; Japanese
• Published: 16.02.2015
• Subjects: DETECTING MASSES OR OBJECTS; GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; MEASURING; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To provide a gate-type magnetic body detector that issues a warning of increase of change in magnetic flux density, as means for detecting and reporting entry of a magnetic body into an MRI examination room in order to prevent the magnetic body from being attracted by a strong magnet of an MRI diagnostic apparatus.SOLUTION: In a magnetic body detector 21, a plurality of magnetic sensor sets 1 are installed around a passage 13 of a gate. Each of the magnetic sensor sets 1 is composed of two or three magnetic sensors 2, 3, 4, and respective detection axes 5, 6, 7 of the sensors are arranged at angles of 90±30° including an orthogonal angle to each other. A change in magnetic flux density caused by movements of magnetic bodies 22, 23 is detected by the magnetic sensor sets 1; a scalar and angle of a vector of the change in magnetic flux density is calculated; and if any of the values in the calculation result is greater than a predetermined threshold 17 and if it is detected that the movement is in the direction of entering the room, a warning by sound, light or the like is issued to the user thereby to prevent the magnetic bodies 22, 23 from entering the room. 【課題】 ＭＲＩ診断装置の強力な磁石に磁性体が吸着されないように、ＭＲＩ診断室への磁性体の入室を検知して告知する手段として、磁束密度の変化が大きくなったことを警告するゲート型の磁性体検知機の提供を図る。【解決手段】 検知軸5(6)(7)を相互に直交を含む９０?３０?の角度で配置させた２又は３個の磁気センサ2(3)(4)からなる磁気センサ組1を、複数組ゲートの通過部13周囲に配置する。磁性体22(23)が移動することによって発生する磁束密度の変化を磁気センサ組1で検知し、磁束密度の変化のベクトルのスカラと角度 を演算し、その演算結果が設定した閾値17より大きく、かつ、ゲートを入室方向に移動することを検知した時に、音声や光などによって使用者に告知を行ない、磁性体22(23)の入室を阻止する形態の磁性体検知機21とした。【選択図】図１