Patents by Inventor David A. Picco

David A. Picco 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: 5840158
    Abstract: A method for the manufacture of paper comprising the steps of:a) forming an aqueous cellulosic papermaking slurry;b) adding an effective coagulating amount of a coagulant and a flocculant to said cellulosic papermaking slurry, wherein said coagulant is prepared by blendingi) an effective coagulating amount of an aqueous conditioned colloidal silica sol with an average particle size within the range of from 1 to 150 nm and wherein the aqueous colloidal silica sol is conditioned by contacting said sol with a strong acid cation exchange resin, andii) an effective coagulating amount of a cationically-charged water-soluble polymeric coagulant;c) draining said cellulosic suspension to form a sheet; and,d) drying said sheet.The components of the invention are blended together so that addition is simultaneous. The colloidal silica is conditioned by passing over a cationic exchange resin prior to addition of cationic polymer.
    Type: Grant
    Filed: April 7, 1997
    Date of Patent: November 24, 1998
    Assignee: Nalco Chemical Company
    Inventors: Pek Lee Choo, Bruce A. Keiser, Michio Kobayashi, Maureen B. Nunn, David A. Picco, Kristine S. Salmen
  • Patent number: 5667697
    Abstract: This invention relates to the clarification of natural waters containing turbidity-causing components. This method comprises the addition of a stable colloidal silica suspension and water based polymeric coagulant to the turbid water. The components of the invention may be added independently, or blended together so that addition is simultaneous. The colloidal silica may also be conditioned by passing over a cationic exchange resin prior to addition of cationic polymer.
    Type: Grant
    Filed: August 21, 1996
    Date of Patent: September 16, 1997
    Assignee: Nalco Chemical Company
    Inventors: Kristine S. Salmen, Pek Lee Choo, David A. Picco, Michio Kobayashi
  • Patent number: 5620629
    Abstract: This invention relates to a composition of matter of a silica sol/water soluble cationic polymer mixture. The colloidal silica may also be conditioned by passing over a cationic exchange resin prior to addition of cationic polymer.
    Type: Grant
    Filed: November 26, 1995
    Date of Patent: April 15, 1997
    Assignee: Nalco Chemical Company
    Inventors: Kristine S. Salmen, Pek L. Choo, David A. Picco, Michio Kobayashi
  • Patent number: 5554298
    Abstract: The invention comprises a method of preventing deposition of oil on steel mill scale particles comprising adding from about 1 part per million to about 500 parts per million of an amine acrylate/acrylic acid copolymer to mill flume water. Once the copolymer is added, deposition of oil onto scale particles is prevented. The recovered mill scale has less than 2% oil by weight on the scale, making it suitable for recycle to the steelmaking process. Oil and water are subsequently separated with a greater percentage of oil being recovered.
    Type: Grant
    Filed: January 20, 1995
    Date of Patent: September 10, 1996
    Assignee: Nalco Chemical Company
    Inventors: Ronald D. Kochik, David A. Picco, Michael L. Braden, Kristine S. Salmen