Target Micro Scan metal detectors use a balanced, three-coil, system to detect small particles of non-ferrous and stainless steel. The coils are wound on a non-metallic frame, each parallel with the other. The center coil is connected to a high frequency radio transmit¬ter. Coils on either side of the transmitter coil are receivers. As these two coils are identical and placed the same distance fro
m the transmitter, they receive the same signal and produce an identical output voltage. When the coils are connected in opposition, the output is cancelled, resulting in a zero value. A schematic of the coil configuration is shown in figure 1. When a particle of metal passes through the coils of a metal detector, the high frequency field is disturbed under one coil, chang¬ing the voltage by a few micro volts. The state of balance is lost and the output from the coils is no longer zero. It is this phenomenon that is used to detect metal. What can be detected in Target Metal Detectors
Target Micro Scan Metal Detectors are able to detects all types of metals ferrous, nonferrous or stainless steel contaminations. The ease of detection will depend on their magnetic permeability and electrical conductivity. The size, shape and orientation (with respect to the detector coils) of the metal particle also is important. Since size, shape and orientation of metal contaminants is not possible to control, it is best to operate a metal detector at the highest possible sensitivity setting. Most Micro Scan Metal detection Systems are fitted or integrated with a food graded PU, or plastic conveyor belt running through the metal detecting head to carry product through the metal detector. Often Target Micro Scan metal detectors with conveyors are designed with a mechanism to reject or discharge products or packages in which metal has been detected.
