Method for inspecting the elements of piping systems by electromagnetic waves
AssigneeTokyo Gas Co., Ltd.
InventorsKiichi Suyama, Takashi Imaoka
Life of this patent
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AssigneeTokyo Gas Co., Ltd.
InventorsKiichi Suyama, Takashi Imaoka
Estimating the term…
Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection. When either the transmitting antenna or the receiving antenna is moved, the frequency of electromagnetic waves can be a frequency propagated in the pipe or can also be lower than the cut-off frequency. On the other hand, the antenna can be made long and kept in the pipe, to use a frequency lower than the cut-off frequency without moving the antenna
A method for detecting and locating faults and leaks in an existing underground piping system using electromagnetic waves, consisting essentially of moving a transmitting antenna of a transmitter outside the underground piping system along the direction of the pipe to be inspected, to transmit electromagnetic waves from outside the piping system;
A method for detecting and locating faults and leaks in an existing underground piping system using electromagnetic waves, consisting essentially of the steps of moving a transmitting antenna of a transmitter along the pipe to be inspected outside the piping system, while transmitting electromagnetic waves having a frequency lower than the cut-off frequency for the pipe used as a wave guiding channel of electromagnetic waves, from outside the piping system;
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