| 摘要 |
1494536 Making electric heaters BOSCHSIEMENS HAUSGERATE GmbH 19 Nov 1975 [19 Dec 1974] 47686/75 Addition to 1427586 Heading B3A [Also in Divisions F4 and H5] A heat exchanger comprises a first tube 4 wherein a liquid (e.g. water) is heated, said tube being formed in one piece (e.g. by extrusion) with a second tube 10 of triangular cross-section and containing an electric resistance heater. In use, the upper surface 12 of the tube 10 is utilized as a hot-plate surface (e.g. in a coffeemaking machine), the tube unit being bent to U-shape in the plane of the surface 12. In an extruded tubular structure 4, 10 as initially formed, the tube 10 may be of circular, oval or multisided cross-section. After inserting the electric heater spiral or coiled filament 8 and surrounding it with a suitable electrically insulating material 6, the tube 10 is deformed to the triangular cross-section such as shown, to compress or compact the material 6.
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