Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Kernforschungsanlage Julich

Peter Pflaum

Hartmut Luhleich

Hubertus Nickel

Francisco J Dias

Francesco Dias

Arno Schirbach

Aristides Nauomidis

Willi Hannen

A method of and an apparatus for the drying of articles, especially foodsfs, biological materials and other substances susceptible to cell damage with overheating, wherein the material is spread in a high-vacuum vessel directly adjacent a cooled condenser and is subjected to a vacuum by a pump capable of developing pressures as low as about 0.1 mbar. The chamber is evacuated until there is a noticeable formation of the condenser whereupon the connection between the pump and the chamber is closed and the product is heated to evaporate liquids but below a predetermined temperature (say a maximum of 50.degree. C.) while the condensate resulting from the evaporation is collected directly below the product and is discharged.

Vacuum-drying method and apparatus

In order to prevent a protective carbide layer on a graphitic molded arti from splitting off under thermal stress, an external carbide layer is provided on a graphitic molded article having a graded content of silicon or zirconium (in the carbide state) that increases from near zero at the interior boundary of the layer to about 50 atomic percent at the exterior. Such a layer is produced either by dipping the graphitic molded article into melted silicon, dipping it into a succession of suspensions of carbon and either silicon or zirconium, with a greater silicon or zirconium content in each successive dip, the suspensions also including a binder resin, or by applying layers of a paste of carbon and either silicon or zirconium, also with some resin, each successive layer having a higher silicon or zirconium content. In the case of the successive dipping into suspensions, the article is dried after each dip and then heated to harden the binder, and in the case of application of successive paste layers, the binder is likewise hardened each time. In each case, the treatment terminates with heating to a coking temperature, followed by a rapid rise of temperature to a value at which silicon carbide or zirconium carbide will be formed, followed by cooling to room temperature.

Graphitic molded article with corrosion-resistant surface layer stable

In order to prevent a protective carbide layer on a graphitic molded article from splitting off under thermal stress, an external carbide layer is provided on a graphitic molded article having a graded content of silicon or zirconium (in the carbide state) that increases from near zero at the interior boundary of the layer to about 50 atomic percent at the exterior. Such a layer is produced either by dipping the graphitic molded article into melted silicon, dipping it into a succession of suspensions of carbon and either silicon or zirconium, with a greater silicon or zirconium content in each successive dip, the suspensions also including a binder resin, or by applying layers of a paste of carbon and either silicon or zirconium, also with some resin, each successive layer having a higher silicon or zirconium content. In the case of the successive dipping into suspensions, the article is dried after each dip and then heated to harden the binder, and in the case of application of successive paste layers, the binder is likewise hardened each time. In each case, the treatment terminates with heating to a coking temperature, followed by a rapid rise of temperature to a value at which silicon carbide or zirconium carbide will be formed, followed by cooling to room temperature.

Making temperature-stable protectively coated graphite molded body

Carbonaceous material such as carbon powder is coated with a carbonizable nder in a continuous process in which the carbon particles and the binder, preferably together with a solvent, are introduced continuously into a vessel in which a continuous stream of a liquid vehicle in which the binder is insoluble is likewise introduced. The coated particles are then separated from the liquid phase by decantation or filtration.

Growing community of inventors

Julich, Germany

Peter Pflaum