Patents by Inventor Raymond F. Earl

Raymond F. Earl 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).

  • Air admittance valve for use in drainage systems
    Patent number: 4867802
    Abstract: An air admittance valve for use in drainage systems comprising a housing with an opening therein through which air passes into the drainage system, and a pivoted closure member adapted to close the opening and openable on a pressure difference between the system and the exterior.
    Type: Grant
    Filed: June 23, 1988
    Date of Patent: September 19, 1989
    Inventor: Raymond F. Earl