DETECTOR FOR JOINT POSITION OF BURIED CAST IRON PIPE

摘要

PURPOSE:To detect easily and surely the joint position of a pipe by moving a magnetic sensor along the pipe, comparing the pattern of a detection signal with a standard pattern, discriminating the presence or absence of the joint and calculating thereafter the joint position by arithmetic operation. CONSTITUTION:The magnetic sensor 1 is moved by a moving means 3 along the cast iron pipe 4 and the differential signal which is shifted in the phase is outputted therefrom. The pattern of the differential signal and the change pattern stored in a storage means 7 are compared and collated by a means 8 for calculating the joint position and whether the patterns coincide or not is discriminated. The means 8 calculates the position of the joint 9 by the arithmetic operation using the relation between the magnetic pole position and the end position of the pipe 4 if both patterns coincide and the joint 9 exists within the moving section of the sensor 1.