Patents by Inventor Johannes van Leeuwen

Johannes van Leeuwen 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).

  • Apparatus for scraping sludge from the surface of a body of liquid
    Patent number: 4390430
    Abstract: Sludge floating on the surface of liquid protrudes upwardly through a stabilization grid and is removed by scraping means into a gutter. In order to prevent the scraping means pushing the sludge back downwardly through the grid, the scraping means is provided with a knife which is driven in a forward movement towards the gutter and a return movement away from the gutter. In the forward movement the knife is tilted downwardly towards its free edge so as to cut the sludge and push it into the gutter. During the return movement, the free edge is raised above the grid.
    Type: Grant
    Filed: February 25, 1981
    Date of Patent: June 28, 1983
    Assignee: Esmil B.V.
    Inventor: Johannes van Leeuwen