NEEDLE DETECTOR FOR FOODS, CHARGE PAYING DEVICE THEREOF AND ITS USAGE

摘要

PROBLEM TO BE SOLVED: To obtain a needle detector with simpler structure than conventional needle meters and low cost and detectable of needle and the like having a height of 110 mm or more from a magnetic pole face of a pole piece and mixed in foods to be detected. SOLUTION: A needle detector 30 using U-shape permanent magnets 48 and search coils 50 and 51 wound around the magnetic poles N and S at their both ends has alarm means 40 and 42 operating alarm when detecting an object to be detected such as needles of a magnetic body mixed in foods to be detected and a sensitivity control means 46 for controlling the sensitivity by controlling the amplification of detecting current. The needle detector 30 is arranged facing the back of the vertical detection plane 30a where the pole face 48a and 48b at the tip ends of the magnetic poles N and S on both ends of the U-shape permanent magnets 48 and sets the pitch gap of the magnetic poles N and S on both ends of the U-shape permanent magnet 48 to 100 mm or longer.