Abstract: In a process for fabricating an injection-molded tube sheet of thermoplastic material, for use in an apparatus for transferring heat and/or mass, with at least 25 through-holes for taking up tube ends, a melt is first distributed in the injection mold over the entire cross-sectional area before being pressed into the region of the mold where the tube sheet proper is formed. The injection mold has a needle disposed therein for each hole of the tube sheet being fabricated. After cooling, the portion of the thermoplastic melt without through holes, that is that overlaying the needles, is removed to produce the tube sheet.

Abstract: In an injection-molded tube sheet of thermoplastic material for apparatus for transferring heat and/or mass with at least 25 through-holes for taking up tube ends, the holes have a hydraulic diameter of at most 3 mm and the minimum web width between neighboring holes is at most 0.4 mm. The thickness of the tube sheet ranges from 3 to 10 mm. Such a tube sheet is particularly suitable for the compact arrangement of tube ends and is therefore used for producing apparatus for transferring heat and/or mass. It is fabricated by an injection-molding process in which the melt is first distributed in the injection mold over the cross-sectional area before being pressed into the region of the tube sheet proper.

Abstract: An apparatus for transferring mass and/or heat comprising a casing, at least two tube sheets and a plurality of tubes. The tubes are connected with the tube sheets and the tube sheets are formed such that they are arranged partly in openings provided in the casing and partly outside the casing, overlapping the casing openings. A seal is disposed between sheets and casing inside and outside the casing openings and the tube sheet has been fabricated by casting onto the casing.

Abstract: A heat exchanger comprises at least one group of tubes of thermoplastic synthetic material, the tube ends of a group being packed closely together and the tube ends of adjacent tubes being fused to one another on their end face. Preferably, the tube ends are arranged in a sleeve enclosing the group of tubes, the external tube ends being fused with the sleeve. The heat exchangers are made in such a way that the tube ends are assembled together and inserted into a sleeve. The tubes are placed in vertical position, with their ends essentially upward. Heat is then supplied to the tube ends from above, causing the tube ends to expand and occasionally to fuse with the sleeve.

Abstract: Heat and/or transferring apparatus which comprises at least one group of tubes from synthetic thermoplastic material, in which each tube end is surrounded by a sleeve from synthetic thermoplastic material having no porosity or a prosity of an more than 20% of the wall volume. All tube ends with sleeves of one group are surrounded by a second sleeve, whereby the sleeves of the tube ends have substantially the same length as the second sleeve. On the end face the tube ends are each fused with the sleeve end surrounding the same, adjacent sleeve ends are fused with one another, and external sleeve ends are fused with the second sleeve.

Abstract: Process for permanently fastening the end or ends of at least one rod, made at least partially of a thermoplastic material and having at least one continuous cavity, in at least one opening of a support plate. The opening surrounds at least one rod, with each rod - in order to be fastened - positioned in its designated opening in the support plate. Each rod cavity exhibits a hydraulic diameter which corresponds to at least 10% of the minimum outside cross-sectional dimension of the rod, and the rod walls may exhibit pores which take up a maximum of 20% of the wall volume.