Mitsubishi Hitachi Power Systems, Ltd.

Hitachi-ge Nuclear Energy, Ltd.

Soushi Narishige

Isao Yoshida

Tetsuya Matsui

Akira Nishimizu

Masahiro Miki

Masahiro Tooma

Toshiyuki Hiraoka

To realize an object of providing an eddy current inspection device which is able to control a sensitivity decrease, and is able to reliably detect a defect. An eddy current inspection device of the present invention is provided with an orthogonal detection mode which measures an electromotive force signal using a coil pair which is configured by two coils within the first row coil group, a first intersection detection mode which measures the electromotive force signal using the first coil pair which is configured by the two coils within the first row and second row coil groups that are lined up in a direction which intersects with the scanning direction, and a second intersection detection mode which measures the electromotive force signal using the second coil pair which is configured by the two coils within the first row and second coil groups that are lined up in a direction in which a direction which intersects with the scanning direction is on the same side as the direction through which the first coil pair intersects and has a larger coil pair intersection angle than the coil pair intersection angle of the first coil pair.

Eddy current inspection device

An object of this invention is to sense a transient displacement of the blade position to thereby detect abnormalities early. The invention includes: one or more first sensors mounted so as to be removable from an outer surface of a casing opposed to blade tips; a second sensor for acquiring a signal from a fixed point on a rotor shaft of the blades; a section configured to extract data groups from an output signal of the first sensor on the basis of information acquired by the second sensor; a section configured to average the data groups; a section configured to determine thresholds from averaged data obtained under a healthy condition; and an assessing section configured to compare magnitude of the thresholds and sensor signals obtained during blade status monitoring. Since a transient displacement of blade position can be sensed, abnormalities can be detected early in this invention. This early detection, in turn, enables a rotation to be stopped during an initial phase of blade damage. The invention is therefore advantageous in minimizing impacts on other devices.

Method and device for monitoring status of turbine blades

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Tokyo, Japan

Soushi Narishige