Patents Assigned to Gypsum Industries Limited
  • Gypsum products
    Patent number: 4140536
    Abstract: This invention relates to a method of making a gypsum product wherein a hot homogeneous mixture of pitch and a suitable organic material are mixed with gypsum and water to form a slurry. This slurry is then formed, allowed to set and then heated to a temperature above the melting points of both constituents of the mixture but below the temperature at which there is any significant deterioration of the product.
    Type: Grant
    Filed: March 1, 1978
    Date of Patent: February 20, 1979
    Assignee: Gypsum Industries Limited
    Inventors: Simbert W. Maier, Adriaan J. H. Lamprecht
  • Method and apparatus for treating sewage
    Patent number: 3939067
    Abstract: A method and means for treating sewage using the activated sludge process. Sewage in a circular aeration chamber is given a spiral motion about the chamber centre and this motion is used to cause liquid-borne sludge to flow from the chamber along a canal around the chamber. Part of the sludge is returned from the canal to the chamber under the influence of gravity for recirculation.
    Type: Grant
    Filed: October 30, 1973
    Date of Patent: February 17, 1976
    Assignee: Gypsum Industries Limited
    Inventor: Peter H. Huisman