MANUFACTURE OF IMPREGNANT FOR IMPREGNATED TYPE CATHODE

• Main Authors: TANABE SHOJI, TOYODA TSUTOMU
• Format: Patent
• Language: English
• Published: 20.10.1995
• Edition: 6
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

PURPOSE:To manufacture an impregnant for providing an impregnated type cathode showing a good emission characteristic by supplying the carbonate of a binary or higher system of alkaline earth metals containing Ba or the like as well as the powder of oxide to organic acid for formation into fine droplets, and splashing and instantaneously drying the droplets in the dry air. CONSTITUTION:Powder composed of BaCO3, CaCO3 and Al2O3 having a particle size approximately equal to 5mum or less and mixed at the preset mole ratio, is supplied to the water solution of organic acid (preferably formic acid) for dissolving BaCO3 and CaCO3. A spray dryer is charged with the water solution, while Al2O3 being well dispersed therein, and this solution is sprayed into the dry air at a temperature approximately between 100 deg.C and 200 deg.C for formation into fine droplets. Then, the droplets are splashed into the dry air and instantaneously dried. As a result, an impregnant for an impregnated type cathode having a good emission characteristic can be provided at a simple process.