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:
Sep. 19, 1978
Filed:
May. 08, 1974
Frey Viking Sundman, Karhula, FI;
A. Ahlstrom Osakeyhtio, , FI;
Abstract
A process for bleaching cellulose pulp with molecular oxygen under alkaline conditions and at an elevated temperature in a bleaching zone is disclosed in which oxygen gas is dispersed into an alkaline bleaching solution under an increased pressure, the oxygen-containing, alkaline bleaching solution is heated to at least the elevated bleaching temperature, the pressure of the hot, oxygen-containing, alkaline bleaching solution is lowered to the pressure prevailing in the bleaching zone, and the hot, oxygen-containing, alkaline bleaching solution is brought, in the bleaching zone, into contact with the cellulose pulp to bleach the latter with the oxygen gas released from the bleaching solution.