Tokyo Gas Company Limited

Cxr Co., Ltd.

Cxr Corporation

Osaka Gas Company Limited

Toho Gas Co., Ltd.

Toshihide Kawabe

Yasuharu Hosohara

Shigeru Fujiwara

Kiwamu Suzuki

Kiichi Suyama

Masanori Akita

Takashi Sumi

Seiji Mizukami

Yoshikazu Chiba

Yoshio Ido

Akira Kinoshita

A running apparatus within a pipe runs such that a center axis of a main body of the running apparatus is automatically coincided with a center axis of the pipe during running, and smoothly runs within a curved pipe. The running apparatus comprises two pairs of wheel supporting arms (3a, 3a', 3b, 3b') having an end rotatably fixed to an end portion of the main body (1) of the running apparatus, a wheel for driving the running (5) fixed to each of the other ends of two pairs of wheel supporting arms and rotated by a drive mechanism (a motor), an interlocking mechanism (a slider and a link) provided with a spring for urging two pairs of wheel supporting arms to which the wheels for driving the running are fixed in such a manner as to open around the one end of the main body of the running apparatus, a rotational potentiometer for measuring an angle of incline of each of two pairs of wheel supporting arms so as to output a data of an angle of incline and an attitude control portion (20) for returning an attitude of the main body of the running apparatus to a normal attitude state by controlling the drive mechanism on the basis of the data of the angle of incline with respect to each of two pairs of wheel supporting arms output from the rotational potentiometer.

Self-propelled vehicle within pipe

A flaw sensor for a metal pipe has an exciting coil for generating remote field eddy currents in the pipe. First and second groups of receiving coils are spaced from the exciting coil by respective distances along the axis of the pipe in a region of the generated remote field eddy currents. The first and second groups have respective pluralities of receiving coils with axes perpendicular to the pipe axis and disposed circumferentially about the pipe axis at predetermined angular increments wherein the receiving coils of the second group are staggered relative to the receiving coils of the first group. A third receiving coil is disposed coaxially with the pipe at still another distance from the exciting coil along the pipe axis but also in the region of the generated remote field eddy currents. When a defect in the thickness of the metal pipe is encountered, a magnetic field caused by the defect to be perpendicular to the axis of the pipe is detected by one or more of the receiving coils of the first and/or second group. The third receiving coil detects phase changes to the magnetic field generated parallel to the pipe by the eddy currents. A ratio of phase changes produced by a standard thickness of a reference pipe and a sample subject pipe is used as a correction factor for detected phase changes in a defective pipe to accurately calculate the defective wall thickness.

Remote field flaw sensor including an energizing coil, first and second

The present invention relates to a flaw detector for metal material for maintaining and managing pipelines using a remote field eddy current sensor. An AC signal having constant level and shifted by predetermined phase angle is added to signals received in receiving coils of the remote field eddy current sensor to obtain accurate phase detection in a normal, nonflawed portion of the pipeline to be tested (e.g. uniform thickness, no holes, etc.). By preventing generation of abnormal flaw data, precise diagnosis of the pipeline can be performed. An AGC circuit may be used to maintain at a constant level of received signal. Two sets of spaced apart receiving coils are spaced from an exciting coil a distance greater than a predetermined distance (about two times the pipeline diameter). The set of receiving coils closest to the exciting coil has a greater number of coil turns than the other set. This coil configuration generates sensed coil differential signals having sufficient signal amplitude to permit stabilized and accurate phase detection and comparison for nonflawed and gradually flawed regions in the pipe.

Remote field eddy current sensor for detecting flaws in metal material

The present invention relates to a flaw detector for metal material for maintaining and managing pipelines using a remote field eddy current sensor. An AC signal having a constant level and shifted by predetermined phase angle is added to signals received in receiving coils of the remote field eddy current sensor to obtain accurate phase detection in a normal, nonflawed portion of the pipeline to be tested (e.g. uniform thickness, no holes, etc.). By preventing generation of abnormal flaw data, precise diagnosis of the pipeline can be performed. An AGC circuit may be used to maintain at a constant level of received signal. Two sets of spaced apart receiving coils are spaced from an exciting coil a distance greater than a predetermined distance (about two time the pipeline diameter). The set of receiving coils closest to the exciting coil has a greater number of coil turns than the other set. This coil configuration generates sensed coil differential signals having sufficient signal amplitude to permit stabilized and accurate phase detection and comparison for nonflawed and gradually flawed regions in the pipe.

Remote field eddy current flaw detector for metal material including

The present invention relates to a flaw detector for metal material for maintaining and managing pipelines using a remote field eddy current sensor. An AC signal having a constant level and shifted by predetermined phase angle is added to signals received in receiving coils of the remote field eddy current sensor to obtain accurate phase detection in a normal, nonflawed portion of the pipeline to be tested (e.g. uniform thickness, no holes, etc.). By preventing generation of abnormal flaw data, precise diagnosis of the pipeline can be performed. An AGC circuit may be used to maintain at a constant level of received signal. Two sets of spaced apart receiving coils are spaced from an exciting coil a distance greater than a predetermined distance (about two times the pipeline diameter). The set of receiving coils closest to the exciting coil has a greater number of coil turns than the other set. This coil configuration generates sensed coil differential signals having sufficient signal amplitude to permit stabilized and accurate phase detection and comparison for nonflawed and gradually flawed regions in the pipe.

Remote field eddy current flaw detector for metal pipes having a pair of

Growing community of inventors

Kure, Japan

Toshihide Kawabe