Patents by Inventor Robert B. Pratt

Robert B. Pratt 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).

  • Non-rotating stem valve
    Patent number: 4778150
    Abstract: A rising stem valve comprising a valve body, a two part valve stem and a stem guide washer. The valve body has a valve seat in a passage between an inlet and outlet port. The two part valve stem comprising a rotating stem and a non-rotating stem and the rotating stem has a threaded bore receiving a threaded end of the non-rotating stem. The non-rotating stem has a non-circular cross section external of the threaded bore and is adapted to carry a closure head to the valve seat. The stem guide washer has a bore positioned in mating relationship with the noncircular cross section of the non-rotating stem, whereby the stem guide washer prevents the stem from rotating when the upper stem is rotated.
    Type: Grant
    Filed: March 6, 1987
    Date of Patent: October 18, 1988
    Assignee: Autoclave Engineers, Inc.
    Inventors: Robert B. Pratt, Stephen G. Ratkowski, Donald J. Kalivoda