Patents by Inventor Masahiro Otaka
Masahiro Otaka has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5897062Abstract: A fluid jet nozzle has a water chamber accommodating therein pressurized fluid, an orifice communicating with the water chamber and contracting the fluid from the water chamber, a throat communicating with the orifice and through which the fluid from the orifice passes, a multiplication chamber communicating with the throat and receiving the fluid from the throat for multiplying cavitation, and a diffusion chamber receiving the fluid from the multiplication chamber for diffusing the fluid.Type: GrantFiled: October 18, 1996Date of Patent: April 27, 1999Assignees: Hitachi, Ltd., Babcock-Hitachi Kabushiki KaisyaInventors: Kunio Enomoto, Katsuhiko Hirano, Masahiro Otaka, Kazuo Amano, Eisaku Hayashi, Sadato Shimizu, Ren Morinaka, Kazunori Sato
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Patent number: 5793203Abstract: A measurement system for measuring material deterioration in accordance with a magnetic field of the material in the presence of radiation. The measurement system includes a detection circuit which detects a magnetic field of the material and generates a signal indicative thereof which signal includes noise due to the radiation, a signal processing circuit including semiconductor devices to process the signal generated from the detection circuit and a noise reducing circuit for at least reducing noise in the generated signal which is due to the radiation. The signal processing circuit is installed at a place where a dose equivalent of radiation is equal to or smaller than that of a place where the detection circuit is installed.Type: GrantFiled: December 5, 1995Date of Patent: August 11, 1998Assignee: Hitachi, Ltd.Inventors: Eriko Takeda, Toshikazu Nishino, Masahiro Otaka, Ren Morinaka, Fuminobu Takahashi
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Patent number: 5749384Abstract: An apparatus preventive maintenance having a driving mechanism capable of driving a jet nozzle 24 to cause it to travel upward-and-downward, to rotate and to swing is settled on the top of a housing in the bottom portion of a reactor pressure vessel and on a hole for a fuel support piece, water pumped by a high pressure pump is spouted from a jet nozzle, and cavitation bubbles generated during the spouting are supplied to the positions to be treated for preventive maintenance, such as housings in the bottom portion of the reactor pressure vessel. Therewith, the residual tensile stress in the position to be treated is improved in a releasing direction by the energy generated by the collapsing of the cavitation bubbles.Type: GrantFiled: March 24, 1995Date of Patent: May 12, 1998Assignees: Hitachi, Ltd., Babcock-Hitachi Kabushiki Kaisha, Hitachi Nuclear Engineering Co., Ltd., Hitachi Kiso Co., Ltd.Inventors: Eisaku Hayashi, Koichi Kurosawa, Fujio Yoshikubo, Hideyasu Furukawa, Ren Morinaka, Kunio Enomoto, Masahiro Otaka, Noboru Chiba, Kazunori Sato
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Patent number: 5553106Abstract: Low temperature water in a low temperature water tank 12 installed outside a reactor pressure vessel 9 is pumped by a high pressure pump 15 and supplied through a conductor 17 under pressure. The supplied water is ejected, as a stream of cold water jet 8, from a nozzle 14 connected to the conductor 17 and introduced into the reactor pressure vessel 9 by a driving mechanism. The stream of cold water jet 8 ejected from the nozzle 14 is directed to impinge against a predetermined position of a core shroud 13 in reactor water 11 filled in the reactor pressure vessel 9 and being at temperature higher than the low temperature water. Then, while continuing to eject the cold water jet 8 from the nozzle 14, the nozzle 14 is moved away from the predetermined position, or the ejection of the cold water jet 8 from the nozzle 14 is stopped, allowing the predetermined position to be heated again with the temperature of the reactor water 11.Type: GrantFiled: June 14, 1995Date of Patent: September 3, 1996Assignees: Hitachi, Ltd., Babcock-Hitachi Kabushiki KaishaInventors: Kunio Enomoto, Masahiro Otaka, Kazuo Amano, Koichi Kurosawa, Eisaku Hayashi, Ren Morinaka, Shigeo Hattori, Kasunori Sato
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Patent number: 5537037Abstract: A nondestructive inspecting apparatus is arranged to have an exciting magnet for applying an ac magnetic field to a sample and a SQUID for converting change of a magnetic characteristic of the sample occurring when the ac magnetic field is applied to the sample into an electric signal. The exciting magnet is a cancelled coil assembly composed of plural coils having respective polarities.Type: GrantFiled: March 15, 1994Date of Patent: July 16, 1996Assignee: Hitachi, Ltd.Inventors: Masahiro Otaka, Sadato Shimizu, Kazuo Takaku, Shinji Sakata
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Patent number: 5414356Abstract: 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.Type: GrantFiled: July 30, 1991Date of Patent: May 9, 1995Assignee: Hitachi, Ltd.Inventors: Toshihiko Yoshimura, Tasuku Shimizu, Yuichi Ishikawa, Masahiro Otaka, Yuko Koguchi, Kunio Enomoto, Kunio Hasegawa, Makoto Hayashi, Kazuo Takaku
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Patent number: 5331278Abstract: A non-destructive inspection apparatus includes a magnetic field applying device and a magnetic sensor. The magnetic field applying device is adapted to apply DC and AC magnetic fields to an object to be inspected. Degradation/damage of the object is detected by measuring a magnetic characteristic of the object in a state in which the DC and AC magnetic fields are applied. Also, a non-destructive inspection apparatus includes as a magnetic sensor a plurality of pickup coils and a SQUID(s) connected to the pickup coils and decides the form of a defect of an object to be inspected by producing a difference between outputs of the pickup coils or SQUIDs.Type: GrantFiled: September 11, 1991Date of Patent: July 19, 1994Assignee: Hitachi, Ltd.Inventors: Stephen Evanson, Satoshi Kanno, Masahiro Otaka, Toshihiko Yoshimura, Kunio Hasegawa, Kazuo Takaku
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Patent number: 5329099Abstract: A method of maintaining the housing of a reactor pressure vessel having: a reactor pressure vessel into which cooling water is introduced; a cylindrical housing which penetrates an end bracket of the reactor pressure vessel; and a circumferential weld for securing the intermediate portion of the housing to the reactor pressure vessel by welding, the method of maintaining a housing of a reactor pressure vessel comprising the steps of: remaining the cooling water in the reactor pressure vessel; preventing leakage of the cooling water in the reactor pressure vessel through the housing by sealing the housing; making the inside portion of the housing lower than the seal to be a hollow space of a gas atmosphere; heating a heat affected zone due to welding by using a heating device inserted into the hollow space from a lower portion so as to compressive-yield the inner surface of the housing in the heat affected portion upper than the circumferential weld and tensile-yield the outer surface; and cooling heated portiType: GrantFiled: May 22, 1991Date of Patent: July 12, 1994Assignee: Hitachi, Ltd.Inventors: Kunio Enomoto, Masahiro Otaka, Kunio Hasegawa, Makoto Hayashi, Shinji Sakata, Hideyo Saito, Koichi Kurosawa, Takashi Saito, Yoshinori Karatsu, Motoya Ito
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Patent number: 5305361Abstract: A water jet peening method in which a pressurized water jet flow containing cavities is jetted through a nozzle having a velocity increasing orifice portion and a horn-like jetting hole formed continuously with the velocity increasing orifice portion to impinge against a surface of a metallic material immersed in water and to cause the cavities to collapse at the surface of the metallic member, and a tensile plastic deformation is caused in a surface layer of the metallic material by a local high pressure generated by the impingement and the collapse so that a residual tensile stress in the surface of the metallic member is reduced. In this method, the nozzle is vibrated so that vibration-induced cavities are formed in the vicinity of a nozzle wall surface, and the vibration-induced cavities are caused to impinge against the surface of the metallic member by the pressurized water jet flow containing cavities.Type: GrantFiled: January 25, 1993Date of Patent: April 19, 1994Assignee: Hitachi, Ltd.Inventors: Kunio Enomoto, Masahiro Otaka, Koichi Kurosawa, Hideyo Saito, Hiroshi Tsujimura, Yasumasa Tamai, Keiichi Uraki, Masahito Mochizuki
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Patent number: 5134368Abstract: 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.Type: GrantFiled: November 8, 1990Date of Patent: July 28, 1992Assignee: Hitachi, Ltd.Inventors: Masahiro Otaka, Kunio Enomoto, Kunio Hasegawa, Makoto Hayashi, Tasuku Shimizu, Kazuo Takaku
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Patent number: 5059903Abstract: 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.Type: GrantFiled: September 21, 1988Date of Patent: October 22, 1991Assignee: Hitachi, Ltd.Inventors: Masahiro Otaka, Kunio Enomoto, Kunio Hasegawa, Makoto Hayashi, Tasuku Shimizu, Kazuo Takaku
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Patent number: 4987367Abstract: 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.Type: GrantFiled: September 12, 1989Date of Patent: January 22, 1991Assignee: Hitachi, LtdInventors: Yuichi Ishikawa, Toshihiko Yoshimura, Tasuku Shimizu, Masahiro Otaka, Kazuo Takaku
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Patent number: 4764970Abstract: 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.Type: GrantFiled: April 15, 1986Date of Patent: August 16, 1988Assignee: Hitachi, Ltd.Inventors: Makoto Hayashi, Masahiro Otaka, Tasuku Shimizu, Shinji Sakata
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Patent number: 4510608Abstract: A laser tube including an anode and a hollow cathode and adapted to obtain laser oscillation by utilizing a negative glow generated in a space within the hollow cathode. The laser tube has an elongate cylindrical member in which the anode and the hollow cathode are disposed opposite to each other, and the hollow cathode has formed therein a plurality of holes for communication between its internal space and the space outside thereof. The laser tube may further include a conducting grid provided in proximity to the anode and a conducting grid provided in a cathode dark space.Type: GrantFiled: February 22, 1982Date of Patent: April 9, 1985Assignee: Mita Industrial Co., Ltd.Inventors: Kanichi Fujii, Masahiro Otaka