Abstract: To provide a method and device for detecting buried metal, whereby it is possible to radio (wirelessly) transmit a synchronizing signal, and, when the frequency band of the transmission signal is restricted, to problem synchronous detection using a reference signal having a frequency equal to or greater than the frequency band.

Abstract: A detection method and detection device of buried metal which are capable of detecting singular points, in horizontal and vertical directions, of metal tubes, telecommunication cables, and electric power cables, or the like buried in the ground. A magnetic field component of the direction of 3 axes of a XYZ axis is detected by two or more magnetic sensors installed in the detectable direction, and detects a magnetic field induced to buried metal. While carrying out synchronous detection of these magnetic field components and calculating for each amplitude and each phase of a magnetic field component of the direction of 3 axes, image processing is carried out and it is outputted to a display. While calculating for the position of a singular point, a singular point distinguishes whether it is an over-crossing state, it is an under-crossing state, or it is a branched state from these image data.

Abstract: The present invention provides a leakage detector enabling accurate and stable detection for occurrence and a position of leakage in a buried fluid pipe line and also making it possible for even those not so skilled in the leakage detection work to use the detector. The leakage detector 1 according to the present invention comprises a vibration detector 2 having a pickup 6 incorporating a piezoelectric element; a main body 4 of the detector incorporating voltage amplifiers 31, 37 for voltage-amplifying an output signal and a plurality types of noise removing units 33, 34, 35 for removing noises from the output signal, and a headphone 5. The main body 4 of the detector has a display unit 15 for displaying data for detected vibration sounds on a predefined screen.

Abstract: The present invention provides a leakage detector enabling accurate and stable detection for occurrence and a position of leakage in a buried fluid pipe line and also making it possible for even those not so skilled in the leakage detection work to use the detector. The leakage detector 1 according to the present invention comprises a vibration detector 2 having a pickup 6 incorporating a piezoelectric element; a main body 4 of the detector incorporating voltage amplifiers 31, 37 for voltage-amplifying an output signal and a plurality types of noise removing units 33, 34, 35 for removing noises from the output signal, and a headphone 5. The main body 4 of the detector has a display unit 15 for displaying data for detected vibration sounds on a predefined screen.

Abstract: The vibration detecting apparatus comprises a pickup 2 encasing a piezoelectric element 8 therein, a cord 3 for transmitting an electric signal output by said piezoelectric element 8, and a noise absorbent member 4 in the form of a lump made of rubber, and formed therein with a cord insert path having at least one direction-changing portion 14a, said noise absorbent member being mounted at a suitable position of said cord. The noise absorbent member is preferably made of low repulsion elastic rubber and is preferably spherical. The cord inser path 14 is preferably in the shape of substantially U. According to the aforementioned construction, noises such as a wind-cut sound and a frictional sound generated at the cord can be effectively removed.

Abstract: A leakage-sound detecting apparatus is provided for efficiently detecting water leakage in a plastic pipe by increasing sensitivity to a low frequency sound component and efficiently reducing stray noise, as well as protecting a piezoelectric element. To this end a detection portion and a pedestal portion are connected through a mechanical resonant member formed of a soft material. A low frequency sound component is amplified by the resonant member, and high frequency components are substantially attenuated. In an alternative arrangement a detection portion and a mechanical resonant member mounted on a pedestal portion are connected through a buffer portion having a buffer member arranged therein. When a shock is applied to the bottom of the pedestal portion, due to the apparatus being dropped for example, the buffer member is compressed, and no overload is applied to a piezoelectric element.