Patents by Inventor Mark Andrew Hannah

Mark Andrew Hannah 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).

  • Two-stage oxygen pulping
    Patent number: 4080248
    Abstract: The pulping of lignocellulosic material in the presence of oxygen gas and an alkaline liquid is improved by carrying out the process in two stages. In the first stage, the alkaline liquid is trickled over the material as the oxygen is passed up through the material. In the second stage, the material is submerged in oxygenated alkaline liquid which flows through the material.
    Type: Grant
    Filed: June 28, 1976
    Date of Patent: March 21, 1978
    Assignee: Crown Zellerbach Corporation
    Inventor: Mark Andrew Hannah