Patents by Inventor David A. Ritchie

David A. Ritchie 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).

  • Patent number: 5596948
    Abstract: A system and method of using the system are provided for collecting and analyzing urine from an animal. A cage with a fluid pervious floor is provided for holding an animal. Urine from the animal flows through the cage floor into a hydrostatic column. An analyzing device is engaged with or positioned proximate to the column in position to analyze the urine entering the column. The column is structured to discharge a volume of liquid equivalent to the volume of urine that enters the column. The discharged liquid is received in a container which is located on a scale that weighs the received liquid. Data from the analyzing device and the scale is automatically stored by a data processing system. A rinse container with a liquid rinse is provided to rinse the column. Preferably the data processing system automatically controls valves to automatically rinse the column after each animal urination or after a predetermined period of time has elapsed.
    Type: Grant
    Filed: June 19, 1995
    Date of Patent: January 28, 1997
    Assignee: Ralston Purina Company
    Inventor: David A. Ritchie
  • Patent number: 4216831
    Abstract: A rake head for attachment to a handle such as a golf club shaft has a mounting bracket that removably and replaceably seats on the club shaft and which carries a pair of rake blades. The rake blades are rotatable between an in-line, deployed position and a folded, collapsed position. Abutments limit the rotation of the rake blades, and a holding structure maintains the rake blades in the deployed position.
    Type: Grant
    Filed: March 23, 1979
    Date of Patent: August 12, 1980
    Inventor: David A. Ritchie
  • Patent number: 4141222
    Abstract: An energy recovery system for heating water with by-product heat from a refrigeration system wherein a heat exchanger within a refrigerant compressor hot gas conduit may selectively heat water within a storage tank. The flow of water through the storage tank and heat exchanger is controlled by a pump operating during operation of the compressor, preferably, only when the heat exchanger is sufficiently heated, and a temperature sensing diverting valve causes pumped water to by-pass the heat exchanger when the water temperature within the tank reaches a predetermined maximum value.
    Type: Grant
    Filed: March 29, 1978
    Date of Patent: February 27, 1979
    Assignee: WeatherKing, Inc.
    Inventor: David A. Ritchie