The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 22, 1977
Filed:
Jul. 22, 1974
Canadian International Paper Company, Montreal, CA;
Abstract
A method and apparatus are provided for automatically and simultaneously controlling the solution viscosity and degree of brightness of a pulp during a bleaching process which employs a sequence of chlorination, hypochlorite and chlorine dioxide bleaching reagents. The pulp is monitored during the bleaching sequence by employing an optical device utilizing reflected light of one or two wavebands. The optical monitoring device electronically feeds a control signal to a regulator or computer which regulates the input of one or more of the bleaching reagents. The amounts of reagents added are based upon and made possible by relationships which have now been determined between the light reflectance values of the pulp at various stages of the process and desired viscosity and brightness values. The viscosity is controlled by controlling the hypochlorite addition and the brightness of the fully bleached pulp is controlled by chlorine dioxide addition.