| 摘要 |
A noble metal catalyst is deposited as a firmly-attached thin layer onto a metallic, electrically-conductive wire-, strip-, grid-, fabric- or tubular substrate. Alternatively it is fired onto the metal substrate. In a further alternative, the metal substrate is first coated with a largely porous mass, which is anchored-on by firing and impregnated with noble metal catalysts. The metal substrate is heated to the required oxidation temperature using AC or DC current. Variation of electrical resistance effects temperature control. Gas leaving the converter is employed to pre-heat gas flowing to it. Preferred Features: The substrate is made of alloys used for electrical heating. The total electrical resistance of the foil-like substrate is adjusted by side incisions and/or perforations, or by cutting a configuration with bridging sections, to allow the required oxidation temperature to be reached and held, from a 220 V supply. Using a mixed fabric, connections adjusting heating are made such that only two ends are brought out for heating, using DC or AC current. The heated substrate is coated with a noble metal substrate, also called a wash coat, to a thickness of 10-100 microns m and is fired onto the substrate with or without electrically-insulating mica sheet, and then loaded with noble metal.
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