Hitachi, Ltd.

Yoichi Wakabayashi

Izumi Ochiai

Hiroshi Kurosawa

Keiichi Nakamura

Hiroshi Asao

Masahiro Miyagi

Kenichi Okada

Yoshio Asahino

A parabolic antenna dish has a circumferential reinforcement flange portion defined by a ridge line which is devoid of air holes and a mesh plate portion integrally connected to the inner periphery of the reinforcement flange portion, the mesh plate portion having as many air holes as possible formed in a region which is not smaller than 80% in terms of the radius of the radiowave reflecting surface.

Parabolic antenna dish

A fluid pressure reducing device having a core provided with a peripheral spiral groove and a pipe receiving the core. The portion of the pipe receiving the core is radially contracted so that the ridges of the spiral groove of the core intrude into the inner peripheral surface of the pipe, thereby to form a spiral passage between the pipe and the core. The pressure of a fluid is reduced as the latter flows through the spiral passage. This fluid pressure reducing device is easy to produce and permits an easy fine adjustment of the flow resistance.

Method of producing a fluid pressure reducing device

An internal groove forming apparatus for heat exchanging pipes, having a cylindrical holder adapted to be loosely fitted in a heat exchanging pipe in concentric relationship, and a plurality of groove forming rolling tools arranged on the holder in a plurality of axially spaced, circumferentially oriented rows and rotatably supported on the holder in such a manner that the rolling tools of one of the two adjacent rows are disposed in staggered relationship with respect to those of the other and an imaginary circle circumscribing the rolling tools is interposed between an outer peripheral surface and an inner peripheral surface of the heat exchanging pipe. Axial relative movements of the heat exchanging pipe and the holder enable the rolling tools to form a number of substantially axially oriented grooves on the inner peripheral surface of the heat exchanging pipe.

Internally groove forming apparatus for heat exchanging pipes

Growing community of inventors

Sano, Japan

Yoichi Wakabayashi