Patents by Inventor James A. Erhardt

James A. Erhardt 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).

  • Electronic flow controller for hydronic heating systems
    Patent number: 4863100
    Abstract: This invention relates to an electronic flow control circuit for use in the low voltage section of an existing control arrangement of a hydronic heating system that utilizes motorized zone valves, to provide a means for controlling fluid flow through the system in order to eliminate hydrostatic shock (water hammer) associated with fast closing motorized zone valves.
    Type: Grant
    Filed: April 4, 1988
    Date of Patent: September 5, 1989
    Inventors: James A. Erhardt, Bruce E. Richardson