Abstract: 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.

Abstract: A method of producing a heat transfer wall, including a plurality of minute tunnels parallelly extending and spaced a minuscule distance from each other under an outer surface of the wall in contact with liquid, and a plurality of tiny hole portions formed at the outer surface of the wall above the tunnels and located at regular intervals along the tunnels to maintain same in communication with the outside. Each hole portion includes a projection located in the hole portion including a hole itself and extending from the vicinity of the hole portion into the hole portion in a manner to traverse same, so that a flow of liquid into the tunnels and a flow of vapor out of the tunnels can be optimally regulated by the projections to enable the heat transfer wall to exhibit a high heat transfer performance.

Abstract: An apparatus for producing a foamed plastic insulating coating in a wire. A gaseous foaming agent is mixed with a resin and passed through a high pressure narrow passage and then through a lower pressure wide passage.The release of pressure, when the resin enters the wide passage, results in a foaming of the resin. The foamed resin is thereafter extruded through an orifice onto a wire. In one embodiment a chemical is added to serve as a nuclei for the gas bubbles formed during foaming. In a second embodiment, a second chemical is added to provide a smoother extruded surface. In still a further embodiment, the pressure in the wide passage is automatically controlled to remain at a predetermined preferred pressure.

Abstract: A method for producing a foamed plastic insulating coating in a wire. A gaseous foaming agent is mix with a resin and passed through a high pressure narrow passage and then through a lower pressure wide passage.The release of pressure, when the resin enters the wide passage, results in a foaming of the resin. The foamed resin is thereafter extruded through an orifice onto a wire. In one embodiment a chemical is added to serve as a nuclei for the gas bubbles formed during foaming. In a second embodiment, a second chemical is added to provide a smoother extruded surface. In still a further embodiment, the pressure in the wide passage is automatically controlled to remain at a predetermined preferred pressure.