Mitsubishi Jukogyo Kabushiki Kaisha

Dainichi-nippon Cables, Ltd.

Shoichi Hamada

Takashi Ishide

Isao Shirasu

Tadashi Nagashima

Atsushi Utsumi

Takashi Akaba

Yoshiaki Kondo

Yoshio Hashimoto

Yasumi Nagura

Shuhei Kuri

Hideyuki Kurokawa

Takao Kuroiwa

Masaru Tomeoka

Yasumi Nakura

Junji Nakayama

Toshiyuki Nakajima

Takuya Kitera

Makoto Ohta

Sunao Oshibe

Masatoshi Takamatsu

Kohei Morisaki

Michito Sakamoto

Masatoshi Sato

Seiichi Kawaguchi

Shoichi Urushibata

Naruo Sakamoto

Takuya Kidera

Masahiko Meka

The known reflecting mirror for a laser beam conisting of a mirror base member and a high-reflectivity metal coating layer formed on the mirror base member for reflecting a laser beam, is improved so as to maintain a high mirror reflectivity without necessitating a cooling facility. The improvements reside in that a coating layer having a small diffusion coefficient is provided on the back surface side of the high-reflectivity metal coating layer, and/or in that at least one layer of dielectric coating layer or layers are provided on the surface of the high reflectivity metal coating layer. Also, an improved laser beam welding apparatus for an inner circumferential surface of a tube is provided by employing the aforementioned improved reflection mirror as a reflecting mirror in an optical condensing system included in a laser beam welding apparatus for an inner circumferential surface of a tube, which apparatus comprises a flexible tube including an optical fiber extended therethrough for transmitting a welding laser beam, said flexible tube being insertable into a work tube, a position detector for detecting a relative position of the flexible tube with respect to the work tube and fixing means of internally expansible type for fixing the flexible tube within the work tube, respectively provided at the front end portion of the flexible tube, a rotary cylinder rotatably supported from the flexible tube, guide support means mounted to the rotary cylinder in a relatively rotatable manner and being able to be held in contact with the inner wall surface of the work tube for holding the rotary cylinder concentrically with the work tube, rotary drive means having its output shaft disposed coaxially with said rotary cylinder for rotationally driving the rotary cylinder, an optical condensing system disposed within said rotary cylinder for leading the welding laser beam emanating from the front end of the optical fiber to the inner wall surface of the work tube in a condensed state, gas scavenging means for discharging metal vapor produced upon welding of the work tube, and gas cooling means for cooling the optical condensing system.

Reflecting mirror for a laser beam and laser beam welding apparatus,

An improved laser beam welding apparatus for an inner circumferential surface of a tube is disclosed herein, which apparatus comprises an elongated flexible tube containing an optical fiber extended along the length thereof so as to transmit a laser beam, position detecting means disposed in the vicinity of the top end of the flexible tube to determine relative positioning thereof with respect to a work tube in which the flexible tube is inserted, holding means provided with an expander and disposed adjacent to the position detecting means for holding the tip end of the flexible tube in the work tube, rotary drive means disposed closer to the tip end of the flexible tube than the holding means, a rotary cylinder connected to the rotary drive means to be rotated with respect to the flexible tube, guide means mounted on the rotary cylinder in a relatively rotatable manner with respect to the rotary cylinder and held in contact with the inner surface of the work tube for supporting the rotary cylinder in a concentric relation to the work tube, and an optical train arranged with the rotary cylinder for receiving a laser beam emitted from the optical fiber and focusing a reflected laser beam onto the inner surface of the work tube.

Laser beam welding apparatus for an inner circumferential surface of a

A plug removal apparatus for removing a mechanical plug fixed in an end of each heat exchange tube of a heat exchanger includes a plug removing mechanism which engages with and pulls out a cylindrical member of the mechanical plug. The plug removing mechanism includes a mandrel insertable into and threadedly engageable with the cylindrical member, a push rod coaxially extending through the mandrel for pushing a cone member of the mechanical plug, an actuating means for selectively moving the mandrel and the push rod towards and from the mechanical plug, and a drive means for selectively rotating the mandrel into engagement with the cylindrical member.

Plug removal apparatus

A fiber scope of the side-viewing type includes an image guide and two light guides disposed on both sides thereof in an objective part. The fiber scope is suitable for the observation of the surface of long articles assembled with narrow gaps therebetween as in an assembly of nuclear fuel rods in a nuclear reactor and a wide field of view can be secured even if an object to be observed stands within a point-blank range of an objective part. Also a plurality of long articles can be simultaneously observed by the fiber scope or the observation can be carried out while moving the fiber scope in the scanning direction. If the fiber scope is used in a radioactive environment, highly radiation resistant optical fibers are used.

Fiber scope

Growing community of inventors

Kobe, Japan

Shoichi Hamada