Patents by Inventor Dale V. Ludwig

Dale V. Ludwig 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: 5269148
    Abstract: A refrigerant recovery unit for large refrigerant systems has a suction compressor which withdraws vapor and a liquid pump which withdraws liquid refrigerant. The compressor and liquid pump pass the fluids to a heat exchanger and a condenser, both located within a bath of chilled liquid. The vapor condenses into a liquid and combines with the liquid refrigerant. The liquid passes to a storage tank. A feedback compressor withdraws vapor from the upper portion of the tank if the pressure is above a selected level and passes it to the condenser for further condensation. A bypass line directs refrigerant vapor to the inlet of the feedback compressor if the tank vapor pressure is below the selected level. A drawdown line allows the feedback compressor to draw all of the refrigerant from the recovery unit after the recovery unit has recovered the refrigerant from the refrigeration system.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: December 14, 1993
    Assignees: Hans E. Brandt, James D. Ludwig
    Inventor: Dale V. Ludwig