Patents by Inventor Per K. Christensen

Per K. Christensen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Delignification and bleaching of cellulose pulp
    Patent number: 4132589
    Abstract: Cellulose pulp is mixed with a base consisting of magnesium oxide, magnesium hydroxide or magnesium peroxide, and treated with oxygen gas at an elevated pressure, at a temperature in the range of 90.degree.-160.degree. C, preferably 120.degree.-140.degree. C for 0.5-6 hours in the absence of alkali metal hydroxide.
    Type: Grant
    Filed: April 14, 1975
    Date of Patent: January 2, 1979
    Inventor: Per K. Christensen