Varta Batterie Aktiengesellschaft

Hoechst Ceramtec Aktiengesellschaft

Stefan Schindler

Heinrich Schelter

Axel Krauth

Ulrich Von Alpen

Juergen Heinrich

Process and apparatus for manufacturing heat exchangers from ceramic sheets, wherein different flow channels are stamped from or pressed into the sheets, and the formed sheets are joined together with a laminating agent. The stacking of the individual sheets is effected using apparatus in which the sheets are transported to the forming means, applicator means and laminating means by horizontally and vertically displaceable, rotatable and pivotable suction plates. The organic component of the ceramic sheets is expelled from the heat exchanger block obtained in two heating steps with an intermediate forming operation to bring the heat exchanger block to its final dimensions, and the block then fired between 1,200.degree. to 1,700.degree. C. The actual sintering temperature depends on the particular ceramic used, which may comprise Si.sub.3 N.sub.4, SiC, cordierite and/or semiconductive barium titanate compounds.

Process for manufacturing heat exchangers from ceramic sheets

By use of new ion conducting but non-electron conducting mixed crystal compounds of the type sodium zirconium phosphatosilicate as the ceramic board material for electronic circuitry it is possible to provide full integration of electronic, electro-chemical and optical components, because the boards simultaneously constitute the solid electrolyte for the miniaturized batteries serving as energy source, and for an electrochromic display system. An illustrative practical embodiment involves housing within a ceramic multi-layer structure a battery with positive electrode and negative electrode for a quartz driving circuit and an electrochromic (ECD) display controlled by an microprocessor. For the flow of current through the ECD there is used a secondary element formed of a WO.sub.3 electrode and a Na-tungstenate electrode as the counter electrode, the WO.sub.3 segments assuming a blue color due to diffusion of Na.sup.+ ions.

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Selb, Germany

Stefan Schindler