Patents by Inventor Helmut Hirschfelder

Helmut Hirschfelder 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).

  • Cellular drum filter for the dewatering of fiber suspensions
    Patent number: 4333836
    Abstract: A cellular drum filter for dewatering suspensions is disclosed, comprising trough means and a filter drum mounted to rotate partially submerged in a liquid suspension in the trough means. Vacuum suction is applied to the surface of the drum from the interior thereof via radial passages communicating preferably with respective axial channels leading to a control head. Each radial passage and each channel has a cross-section whose shape is an arcuate sector of an annulus.
    Type: Grant
    Filed: April 29, 1980
    Date of Patent: June 8, 1982
    Assignee: Voith S.A.
    Inventors: Fritz Peroutka, Helmut Hirschfelder