通常金属检测仪由
Usually metal detectors are made by
两部分组成，即金属检测仪与自动剔除装置，其中检测器为核心部分。检测器内部分布着三组线圈，即中央发射线圈和两个对等的接收线圈，通过中间的发射线圈所连接的振荡器来产生高频可变磁场，空闲状态时两侧接收线圈的感应电压在磁场未受干扰前相互抵消而达到平衡状态。
It consists of two parts, i. e. metal detector and automatic removal device, in which the detector is the core part. There are three groups of coils inside the detector, namely the central transmitting coil and two equivalent receiving coils. The high frequency variable magnetic field is generated by the oscillator connected by the middle transmitting coil. In idle state, the inductive voltage of the receiving coils on both sides cancels each other before the magnetic field is disturbed and reaches the equilibrium state.
一旦金属杂质进入磁场区域，磁场受到干扰，这种平衡就被打破，两个接收线圈的感应电压就无法抵消，未被抵消的感应电压经由控制系统放大处理，并产生报警信号（检测到金属杂质）。系统可以利用该报警信号驱动自动剔除装置等，从而把金属杂质排除生产线以外
Once the metal impurities enter the magnetic field area, the magnetic field is disturbed, the balance is broken, the inductive voltage of the two receiving coils can not be offset, the uncoupled inductive voltage is amplified by the control system, and an alarm signal is generated (metal impurities are detected). The system can use the alarm signal to drive the automatic eliminating device and so on, so as to exclude metal impurities from the production line.