Patents by Inventor Raul Calderon De Palacio

Raul Calderon De Palacio 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).

  • Level indicators for liquids
    Patent number: 4059995
    Abstract: A liquid level indicator comprises a mercury-filled U-tube having a plurality of branches and calibrating rods for insertion into the branches. One arm of the U-tube is subject to the hydrostatic pressure in the receptacle holding the liquid whose level is to be indicated, and the level of mercury in the other arm indicates the liquid level via a colored liquid.
    Type: Grant
    Filed: July 28, 1976
    Date of Patent: November 29, 1977
    Inventor: Raul Calderon De Palacio