Abstract:
A heat transfer tube having surface enhancements so as to improve the thermal performance and increase the heat transfer capacity. The heat transfer tube has an inner surface having a layer of sintered, soldered or brazed metal powder thereon.
Abstract:
The invention relates to a method for improving the liquid flow properties, such as its wettability and capillary flow, of a heat transfer surface prepared on a piece made of a metal, ceramic, polymeric or composite material or a combination thereof, or on a metal piece advantageously made of copper, a copper alloy, aluminum, an aluminum alloy or steel or a combination of these metals. The piece with a heat transfer surface is subjected to oxidation by heating the same under an oxygen-rich atmosphere or using at least one chemical oxidizer. The invention also relates to the use of a heat transfer surface prepared with the help of the method.
Abstract:
The purpose of the method developed is to form on top of a heat transfer surface a porous surface layer, which is to be fixed to the surface below it at a temperature and time applicable for industrial production. The heat transfer surface is copper or copper alloy. The powder forming a porous surface is fine-grained copper oxide powder, which is reduced to metallic copper on the heat transfer surface during heat treatment. The invention also relates to the heat transfer surface of copper or copper alloy, on which a porous layer has been formed from metallic copper, which is manufactured by reducing copper oxide powder and is attached using brazing solder.
Abstract:
A heat transfer tube having surface enhancements so as to improve the thermal performance and increase the heat transfer capacity. The heat transfer tube has an inner surface having a layer of sintered, soldered or brazed metal powder thereon.
Abstract:
The invention relates to a method for joining a metal piece of aluminum or aluminum alloy to a metal piece of copper or copper alloy or to another piece of aluminum or aluminum alloy by soldering. Soldering is carried out using at least one metal powder comprising zinc and tin and that the pieces to be joined are subjected to a heat treatment step carried out at a temperature of 250 - 310 °C. The invention further relates to a solder suited for use in soldering and the use of a solder.
Abstract:
The purpose of the method developed is to form on top of a heat transfer surface a porous layer, which is to be fixed strongly to the surface below it at a temperature and time applicable for industrial production. The heat transfer surface is copper or copper alloy, preferably oxygen-free or deoxidised high phosphorous copper. The powder forming a porous surface is fine-grained copper powder or copper alloy powder. In the method according to the invention, a brazing solder containing preferably nickel, tin and phosphorous alloyed with copper, is brought to the heat transfer surface. The invention also relates to the heat transfer surface onto which a porous surface is formed by means of a powder of copper or copper alloy and the brazing solder described.
Abstract:
A method and apparatus for fabricating an oxygen-free copper product (P), such as oxygen-free copper wire, tube or rod, from copper oxide powder. The method comprises the reduction and melting of copper powder, and casting of molten oxygen-free copper into a copper product (P). Copper oxide is melted in an induction crucible furnace (1) and the oxygen-containing melt is reduced by bringing it into contact with a carbon-containing material (c). The apparatus includes an induction crucible furnace (1), which is arranged to function as a melting and reduction furnace for melting copper oxide into an oxygen-containing melt and reducing the oxygen-containing melt.