Patents by Inventor David R. Haldeman

David R. Haldeman 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).

  • Use of very high charge cationic polymers in biological sludge dewatering
    Patent number: 4396513
    Abstract: A method of dewatering bio-sludge is disclosed. This method comprises adding to the sludge, an effective amount for the purpose of an acrylamide/dimethylaminoethylmethacrylate methylchloride copolymer having a cationic charge density of 90%.
    Type: Grant
    Filed: September 8, 1981
    Date of Patent: August 2, 1983
    Assignee: Betz Laboratories, Inc.
    Inventor: David R. Haldeman