초록 ▼

The invention comprises a method and apparatus wherein an insert, preferably made of plastic and preferably allowing a melt-on bonding with the tubes and whose floor has a traversing opening for each tube, is inserted into the first part of the injection mold (top mold or bottom mold) as a positioni

The invention comprises a method and apparatus wherein an insert, preferably made of plastic and preferably allowing a melt-on bonding with the tubes and whose floor has a traversing opening for each tube, is inserted into the first part of the injection mold (top mold or bottom mold) as a positioning element for the tubes in such a manner that the insert is at least partially locked or secured into the first part of the injection mold. A tube is then placed in each opening of the insert. A mandrel is then placed in each tube, whereupon the injection mold is locked in such a manner that, if necessary, the mandrels are locked into the second part of the injection mold (bottom mold or top mold). A molten thermoplastic material is then injected, via a sprue provided in the injection mold, into a cavity formed by the injection mold, the insert and the tube ends. The parts of the injection mold are separated after cooling of the thermoplastic material, which is maintained under pressure during the cooling at least initially. The mandrels are then removed and the tubes bonded to the insert by the thermoplastic material are removed from the first part of the injection mold and, if appropriate, the free ends of the tubes are also bonded to a second insert by means of the injection mold.

대표청구항 ▼

A method for the production of heat and/or fluid exchangers comprising a plurality of tubes firmly bonded to an insert by injection molding of a plastic material by means of an injection mold comprising at least a first part and a second part and further comprising mandrels which are adapted to be i

A method for the production of heat and/or fluid exchangers comprising a plurality of tubes firmly bonded to an insert by injection molding of a plastic material by means of an injection mold comprising at least a first part and a second part and further comprising mandrels which are adapted to be insertable into the tubes, said method comprising: inserting and securing a tube positioning insert into said first part of said injection mold, said insert including a floor containing a traversing opening for each tube; inserting a said tube into each opening of the insert, said tubes being made of nonporous plastic material or porous plastic material with a pore volume of up to 90%, each tube having a hydraulic diameter dh of from 0.5 to 25 mm and a wall thickness at the thinnest point of from about 5 to 25% of said hydraulic diameter dh; inserting a mandrel into each tube in such a manner that the mandrels ensure support for the tubes over the total length to be embedded in a tube base; closing said injection mold; attaching said first and second parts of said injection mold to each other; heating the tubes to a temperature Tc that is below the melting point temperature Tm of the tube material, and heating the plastic material to a temperature Ti that is higher than Tm, the temperature differentials Ti-Tm and Tm-Tc being chosen so that when the molten plastic material is injected, the tubes are temporarily heated to a high enough temperature to be firmly fused to the insert in the area of the insert openings at least over a distance equal to the thickness of the tube walls; injecting a molten plastic material under high pressure through a sprue provided in the injection mold and into a cavity formed by the injection mold, the insert and the tube ends, said insert, said tubes, and said plastic material all comprising thermoplastic polymer of the same basic structure where said insert and said tube are firmly bonded by said plastic material; cooling the plastic material while said plastic material is maintained under pressure; separating said first and second parts of said injection mold, removing said mandrels, and removing said tubes which are now firmly bonded to said insert by said plastic material from said first part of the injection mold.