Rudi W Schleinkofer

US Patent:

41284542, Dec 5, 1978

Filed:

Dec 7, 1977

Appl. No.:

5/858265

Inventors:

Rudi W. Schleinkofer - Nashua NH

Assignee:

Ingersoll-Rand Co. - Woodcliff Lake NJ

International Classification:

D21C 914
D21C 1106

US Classification:

162 49

Abstract:

Wood pulp is bleached with chlorine dioxide gas. The gas is obtained by feeding a chlorine dioxide solution to a stripper. Shredded or fluffed pulp is exposed to a controlled amount of chlorine dioxide gas for a time period sufficient to obtain the required pulp brightness. The amount of unused chlorine dioxide gas is continuously monitored. The controlled amount of chlorine dioxide gas fed to the bleaching system is automatically adjusted by controlling the amount of chlorine dioxide solution fed to the stripper in response to changes in the amount of unused chlorine doxide gas leaving the bleaching system. Unreacted gases are recycled back to the stripper in response to the concentration of chlorine dioxide gas conducted from the stripper to the reaction area.