Hitachi, Ltd.

Tasuku Shimizu

Shinji Sakata

Makoto Hayashi

Kunio Enomoto

Masahiro Otaka

Kazuo Takaku

Kunio Hasegawa

Yuichi Ishikawa

Nobuyoshi Hosaka

Toshihiko Yoshimura

Tsukasa Ikegami

Asao Nishimura

Hideo Miura

Satoshi Kanno

Ryoichi Kaneko

Kozo Tamura

Masatoshi Tanabe

Shigeo Hattori

Tetsuo Horiuchi

Nobuo Shimizu

Yasuhiko Otawara

Wataru Sagawa

Hirotsugu Fujimoto

Naoaki Shibashita

Isao Sugihara

Kiyoshi Shimomura

Kenzo Mikada

Yuko Koguchi

Hirakazu Yokota

Hisao Ito

Terunobu Koike

A fluxmeter includes an application unit for applying a magnetic field, a superconducting quantum interference element and a flux transmitting circuit. The flux transmitting circuit includes a pickup coil formed of a superconducting print coil and a core for the pickup coil. The core is formed of a soft magnetic material. The core serves to suppress the leakage of magnetic flux to magnetically couple the pickup coil and the superconducting quantum interference element efficiently to improve the sensitivity and resolution of the fluxmeter. The pickup coil may be manufactured by photolithography, sputtering, laser beam deposition, MBE deposition, MOCVD or spray pyrolysis.

Fluxmeter including squid and pickup coil with flux guiding core and

On the basis of a finding that a magnetic hysteresis of a metal material, among magnetization characteristics changing with secular degradation of the metal material, shows a clear correspondence with the degree of degradation of the metal material, a change in such a magnetization characteristic is measured to estimate the degree of secular degradation of the metal material. In a typical embodiment, a superconducting quantum interference device is used to detect the magnetization characteristic of a measuring object. According to the present invention, the degree of embrittlement of a metal material used in an environment of high temperatures can be quickly detected in a non-destructive fashion so that the danger of brittle fracture of the metal material can be reliably prevented.

Apparatus for magnetically detecting degradation of metal material using

A method and apparatus for inspecting the change in a water quality in terms of the change in a corrosion rate by detecting the capacity change between opposed electrodes due to the corrosion of electrode surfaces. As a result, the water quality can be continuously monitored over a long time while leaving the electrodes in the water to be inspected. Thus, the method and apparatus are suited for controlling the water quality especially in an atomic reactor vessel.

Water quality inspection method and apparatus therefor

On the basis of a finding that a magnetic hysteresis of a metal material, among magnetization characteristics changing with secular degradation of the metal material, shows a clear correspondence with the degree of degradation of the metal material, a change in such a magnetization characteristic is measured to estimate the degree of secular degradation of the metal material, In a typical embodiment, a superconducting quantum interference device is used to detect the magnetization characteristic of a measuring object. According to the present invention, the degree of embrittlement of a metal material used in an environment of high temperatures can be quickly detected in a non-destructive fashion so that the danger of brittle fracture of the metal material can be reliably prevented.

Method and apparatus utilizing a magnetic field for detecting

Measurement of a physical property such as coercive force of a member to be inspected is performed at a plurality of locations in one region of the member. Similar measurement is performed in a plurality of different regions of the member and a maximum or minimum value (extreme value) is determined for each of the regions. On the basis of the extreme values thus determined, a recurrence period is determined in accordance with an extreme value statistic theory with the aid of a computer, whereon an estimated maximum value of the physical property of the member as a whole is determined from the recurrence period. On the basis of the estimated maximum value, the degree of deterioration of the member is predicted by the computer by consulting the data indicating the previously determined relation between the physical property and the degree of deterioration.

Method and apparatus for predicting deterioration of a member

A method for improving residual stress in a circumferential weld zone of a piping and the like which includes preventing deformation of the weld zone, and causing a local expansion or contraction of a portion of the piping axially spaced from the weld zone thereby effecting a plastic working so as to increase or decrease the diameter of piping. The method can effectively be applied to apparatus and pipe system which are used in a corrosive environment and under action of a static or dynamic outer load.

Method of improving residual stress in circumferential weld zone

A method system for assessing the safety of a rotor of a shrinkage fitted type wherein an opening displacement of a crack is determined an elastic-plastic fracture method and a reduction in shrinkage fitting force is calculated based on the crack opening displacement. The safety of the rotor is assessed based on the reduction in shrinkage fitting force caused to occur by the opening of the crack.

Method of and system for assessing the safety of shrinkage fitted type

The invention scans potential measurement terminals on the surface of a structural member to measure a potential distribution on the surface, detects the direction of a crack from the potential distribution and determining a detailed potential distribution in the direction of the crack thus detected. This potential distribution is compared with master curves of the potential distributions of cracks of various shapes, that have been obtained by analysis in advance, in order to detect the shape of the crack. The present invention can detect accurately a crack shape.

Method and apparatus for detecting cracks

A method of subjecting a welded structure to heat treatment in which a tensile yield is produced on an inner surface of the welded structure and a compressive yield is produced on an outer surface of the welded structure by the steps of placing a cooling medium in the interior of the welded structure and heating the outer surface of the welded structure to cause a difference in temperature to exist between the inner surface and other surface of the welded structure. The method further includes the step of locally heating a weld by means of a heating member to improve residual stress in a localized area of the weld and repeating the improvement of the residual stress regarding another localized area of the weld.

Method of subjecting welded structure to heat treatment

Piping of a nuclear reactor containment vessel comprises pipes passing through the containment vessel and, extending to the outside of the containment vessel, outer shut-off valves each provided at a portion of the pipe which is located at the outside of the containment vessel for closing the pipe and isolating vessels for covering at least outer surfaces of welded portions of the pipes each being located between an outer wall surface of the containment vessel and a portion including the outer shut-off valve and for isolating the covered portions of the pipes from atmosphere.

Piping of nuclear reactor containment vessel

A water purifier has a deodorization tank for removing ions and odorants by adsorption from running water and a mesh filter for removing dust. The mesh filter is arranged at a water entrance of the deodorization tank. The deodorization tank contains an anti-bacterial membrane having a function of imparting an antibacterial activity to the water by supplying mineral ions to the running water and thereby alkalifying the water. The deodorization tank also has a water exit which is associated with a mineral supply filter for supplying a mineral component to the running water. The mineral supply filter is prepared by molding a powder obtained by adhering a material such as soda glass to the surface of heat-decomposed calcium carbonate.

Water purifier

An anti-corrosive sealing tape comprising a first layer which exhibits conductivity and is prepared by adding fine zinc powder, magnesium oxide and graphite powder to a rubber base; e.g., a butyl rubber containing curing agents and a second layer which plays a role of reinforcing the first layer with imparting waterproofing or thermal insulating properties thereto. This tape will protect metal pipes or structural members against corrosion when wrapped around them.

Anti-corrosive sealing tape

Herein disclosed are a method of heat-treating a weld zone of a piping system, in which the outer wall of a pipe is heated by means of a heating coil, while a coolant is present in said pipe, to establish a temperature difference between the inner and outer walls of said pipe thereby to prevent the weld zone of said pipe from corroding and cracking due to stress, and a heating coil therefor. The aforementioned heating coil is wound on the parent tube and the pipe welding desk generally concentrically thereof thereby to heat substantially uniformly all over the region of said weld zone.

Heat-treating method of weld portion of piping system and heating coil

The X-ray diffraction apparatus of the invention includes means capable of detecting the position and intensity distribution of the diffracted X-ray with respect to a thin bundle X-ray and means for moving the former means to a position at which the former means is capable of detecting the diffracted X-ray, and makes it possible to reliably and easily carry out rough detection of the position of the diffracted X-ray and fine detection of the intensity distribution of the diffracted X-ray without increasing the size of the diffracted X-ray detecting means.

X-Ray diffraction apparatus

Provided is a method for foreseeing the residual life of a structural member, making use of an X-ray, comprising: preparing a plurality of test pieces made of the same material and subjected to the same working and heat-treating conditions as the structural member to be examined of which the fatigue strength is in question; executing fatigue tests with said test pieces till failure under a plurality of different stress conditions; obtaining for each stress the relationship between the residual life of said test piece and the halfvalue width ratio of X-ray diffraction profile; determining, from the above-mentioned relationships, a first relationship region between the halfvalue width ratio and the residual life that is independent of the level of the stress; measuring the halfvalue width ratio of said structural member; and determining the residual life of said structural member from the measured halfvalue width ratio in accordance with said first relationship region.

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Hitachi, Japan

Tasuku Shimizu