Patents by Inventor Douglas S. Chisholm

Douglas S. Chisholm 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).

  • Atomization of molten metals
    Patent number: 4238427
    Abstract: A stream of molten metal from a supply is impinged upon an electrode while an electrical potential is impressed between the supply and the electrode. The zone of impingement becomes a stable electric arc in which the stream is atomized. A carrier gas intersects the spray and removes heat from the metal particles.
    Type: Grant
    Filed: April 5, 1979
    Date of Patent: December 9, 1980
    Inventor: Douglas S. Chisholm
  • Centrifugal extrusion apparatus which heat plastifies material by mechanical shearing action
    Patent number: 4050874
    Abstract: A centrifugal extruder is provided with a friction generating element within a hollow rotor of the extruder. The material to be extruded is heated by shear generated by differential rotation between the extruder rotor and a shear generating element. Heat plastification is obtained adjacent the periphery of the rotor and a very short heat history is added to material treated in the apparatus.
    Type: Grant
    Filed: February 25, 1976
    Date of Patent: September 27, 1977
    Assignee: The Dow Chemical Company
    Inventors: Douglas S. Chisholm, David H. Dawson
  • Process for scrapless forming of plastic articles
    Patent number: 4014965
    Abstract: Plastic articles without foam spots are produced by an improved powder forming process wherein a powder of normally solid, thermoplastic polymer is compacted by means of vibratory energy into briquettes which are subsequently forged and formed into articles of fused polymer.
    Type: Grant
    Filed: November 24, 1972
    Date of Patent: March 29, 1977
    Assignee: The Dow Chemical Company
    Inventors: Steven H. Stube, Douglas S. Chisholm
  • Method for the preparation of plastic lined pipe
    Patent number: 3959424
    Abstract: Plastic lined pipe and fittings are prepared by forming a liner of a plastic material having a diameter greater than the inside diameter of the pipe or fitting to be lined, reducing the diameter of the liner by hydrostatically swaging the liner and inserting the swaged liner into the pipe or fitting and permitting the plastic memory of the liner to cause expansion and form an interference fit of the liner with the pipe.
    Type: Grant
    Filed: December 7, 1973
    Date of Patent: May 25, 1976
    Assignee: The Dow Chemical Company
    Inventors: David H. Dawson, Douglas S. Chisholm