Hitachi, Ltd.

Hitachi Cable, Inc.

Japan Atomic Energy Research Institute

Kimio Kakizaki

Kunio Fujie

Wataru Nakayama

Takahiro Daikoku

Heikichi Kuwahara

Nobukatsu Arai

Hiromichi Yoshida

Tadakatsu Nakajima

Shigeki Hirasawa

Toshihiko Fukushima

Masataka Nishi

Akira Arai

Hisanao Ogata

Toshinari Ando

Susumu Shimamoto

Toshi Sasaki

Yoshihiko Nakayama

Kiyoshi Oizumi

Shigeho Fukuda

Takashi Suzumura

Ryozo Yamagishi

In a heat transfer wall having a number of fine and elongate tunnels adjacent to each other with a minute distance under the surface thereof being in contact with liquid on the heat transfer wall, and a number of fine openings for communicating the tunnels to the outside thereof defined on ceilings of the tunnels along the longitudinal directions thereof with each minute distance, a tongue-like projection is provided which protrudes from an edge of the opening or vicinity of the opening across the opening 1 whereby a flow of fluid passing through the openings provided with the projections is controlled so that heat transfer performance characteristics are improved.

Evaporating heat transfer wall

A novel composite superconductor includes a superconducting material and a normal conducting material. The composite superconductor has a number of closely spaced grooves on a surface being in contact with a refrigerant, and a number of ridges spaced apart from each other by the grooves and having acutely tapered ends. The surfaces of the grooves and the ridges are coated with a thin film of metal or its compound having higher heat resistance than that of the surface of the composite superconductor. Consequently, a high critical heat flux in film boiling and a high cooling capability can be provided, thereby making it possible to decrease the sectional area of the normal conducting material, to increase the effective current density and to miniaturize the size of a magnet.

Composite superconductors

A heat-transfer wall kept at a low temperature so that hot vapor brought into contact with its surface condenses thereon. The surface is grooved at a fine pitch, having thin and sharply tapering ridges in between, with shallower fine-pitch grooves or notches formed in the ridges. The wall may be that of a tube, the grooves may consist of a continuous root in the form of a helix, and the ridges may be bent into the grooves to form rounded crests. The wall contour is made by forming fine-pitch shallow grooves crosswise by knurling and then forming fine-pitch deep grooves by cutting and turning up the surfaces in a plowing manner, for example on a lathe. A grooved die may be used to deform and bend the edges of the ridges toward the deep grooves.

Heat-transfer wall for condensation and method of manufacturing the same

A method of manufacturing a heat-transfer wall for vapor condensation comprising the step of forming on the heat-transfer surface, a number of shallow grooves substantially in parallel at a fine pitch, and then forming, on the heat-transfer surface and in the direction across said shallow grooves, a number of grooves deeper than the shallow grooves at a fine pitch by cutting and turning up the heat-transfer surface in the plowing manner. Said method may further comprise a subsequent step of curling the edges of the ridges formed in the above-mentioned step into said deep grooves.

Method of manufacturing heat-transfer wall for vapor condensation

An apparatus for manufacturing heat transfer tubes for use in evaporators and coolers for freezers, air conditioning units, refrigerators, and the like, with close machining tolerances. It forms cavities, with small openings communicating them with the outside, on the inside of a tube, through three steps of forming a multiplicity of alternate grooves and ribs in parallel on the inner surface of the tube, forming cuts in the concentrically directed crests of the ribs, and then forcing the crests sidewise so that the crest of each rib is bent down onto an intermediate part of the adjacent rib to form a cavity in between.

Apparatus for manufacturing heat transfer tubes

A heat exchanging wall including a base member made of a material comprising graphite as its principal component and a resin as a binder, and a thin outer coat member made of similar material as the material for the base member and applied to one surface of the base member. The material for the base member is cast in a mold having a finely ribbed inner wall surface so that the base member may be formed in such one surface thereof with fine linear grooves. Portions of the thin outer coat member corresponding in position to the grooves in such one surface of the base member are formed with a multitude of small apertures. The heat exchanging wall constructed as aforementioned has high corrosion-resistant characteristics and high heat transfer capabilities, so that the wall is resistant to all corrosive fluids.

Heat exchanging wall and method for the production thereof

A condensing, a heat-transfer wall for liquefying vapor having a temperature higher than the wall by bringing the vapor in contact therewith. There are provided many parallel grooves in the basic surface of the heat-transfer wall, thereby defining ridge portions or build-up portions thereamong. These ridge portions have their tip portions tapered at sharp acute angle. Recessed or concave portions are provided in the tip portions of these ridge portions, and these recessed portions have their surfaces inclined to the basic surface of the heat-transfer wall. The width of the respective grooves ranges from 0.05 to 2.5 mm, and the depth thereof is not more than 10 mm. The thickness of the respective ridge portions ranges from 0.01 to 2.5 mm, and the height there of is not more than 10 mm. The depth of the recessed portions ranges from 0.02 to 0.8 times the depth of the grooves, and the pitch of recessed portion is not more than 2.0 mm. The width of the tip portions of the portions is 0.01 to 1.0 times the pitch of the recessed portions.

Vapor-condensing, heat-transfer wall

A heat transfer wall for boiling liquids having a multiplicity of minute tunnels parallelly extending and spaced a distance of not more than 1 mm under the metal wall surface in contact with liquid. Each tunnel is communicated with the outside by a multiplicity of tiny holes formed at regular intervals of not more than 1 mm along the tunnel. The wall surface portion is in one piece with the wall body. The holes combinedly account for from 2 to 50% of the total surface area of the wall. The regularly formed holes are substantially triangular shaped. The wall is made of either copper or aluminum.

Heat transfer wall for boiling liquids

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Hitachi, Japan

Kimio Kakizaki