Patents by Inventor William H. Lawford

William H. Lawford 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).

  • Patent number: 4211605
    Abstract: An improved, three-stage process for producing high yield chemimechanical pulps from wood or other lignocellulosic materials, such as chips, whereby, in the first stage, the wood or other lignocellulosic material is treated with sulfur dioxide gas or aqueous solution of sulfur dioxide, whereby sufficient sulfur dioxide is present to provide an amount of at least about 1 percent by weight based on weight of wood or other lignocellulosic material; in the second stage, said wood is sulfonated in an aqueous solution of sodium sulfite at a temperature of between about 100.degree. C. and 150.degree. C. for between about 10 and 90 minutes, said aqueous solution having a pH of between about 6 and 8.5 at the end of said sulfonating, without reducing the pulp yield to below about 90 percent; and, in the third stage, subjecting the resulting sulfonated wood to mechanical defibration.
    Type: Grant
    Filed: August 3, 1978
    Date of Patent: July 8, 1980
    Assignee: Canadian International Paper Company
    Inventors: William R. Saxton, William H. Lawford
  • Patent number: 4013506
    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.
    Type: Grant
    Filed: July 22, 1974
    Date of Patent: March 22, 1977
    Assignee: Canadian International Paper Company
    Inventors: John A. Histed, William H. Lawford, Murray J. McLeod