Patents by Inventor Ping-Sun R. Cheung

Ping-Sun R. Cheung 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).

  • Fluid loss additives for cementing compositions
    Patent number: 5217531
    Abstract: Disclosed are cementing compositions and methods of using wherein the cementing compositions comprise: (a) aqueous solution, (b) hydraulic cement, (c) a N-vinylpyrrolidone-acrylamide random copolymer, and (d) a sulfonate containing cement dispersant. The copolymer is present in the composition in an amount of from 0.05 to 5.0 weight percent based on the weight of dry cement. Use of the present invention as a fluid loss additive will result in significant reductions in water loss rate.
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: June 8, 1993
    Assignee: The Western Company of North America
    Inventor: Ping-Sun R. Cheung