Patents by Inventor Douglas W. Northcut

Douglas W. Northcut 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: 6521124
    Abstract: The present invention provides a multi-element filtering system assuring serial filtration of a liquid through multiple filter cartridges while enabling flushing without requiring removal of the filter cartridges. Both conventional and reverse osmosis filtration is performed, sequentially, within the system. After filtration, the water is subjected to ultraviolet irradiation for purification. The filter cartridges are held within a canister which is pressed against the cap and constrained against rotation with the cap. The canister is divided into chambers, and has passages in its floor arranged to enable serial transfer of liquid from one chamber to the next. Flushing employs liquid introduced under normal pressure. Passages leading to the flush liquid outlet enable flushing to proceed when the flush liquid outlet is opened. At other times, filtered liquid will pass through passages leading to the filtered liquid outlet.
    Type: Grant
    Filed: June 26, 2002
    Date of Patent: February 18, 2003
    Inventors: Donald A. Northcut, Douglas W. Northcut
  • Publication number: 20020158001
    Abstract: The present invention provides a multi-element filtering system assuring serial filtration of a liquid through multiple filter cartridges while enabling flushing without requiring removal of the filter cartridges. Both conventional and reverse osmosis filtration is performed, sequentially, within the system. After filtration, the water is subjected to ultraviolet irradiation for purification. The filter cartridges are held within a canister which is pressed against the cap and constrained against rotation with the cap. The canister is divided into chambers, and has passages in its floor arranged to enable serial transfer of liquid from one chamber to the next. Flushing employs liquid introduced under normal pressure. Passages leading to the flush liquid outlet enable flushing to proceed when the flush liquid outlet is opened. At other times, filtered liquid will pass through passages leading to the filtered liquid outlet.
    Type: Application
    Filed: June 26, 2002
    Publication date: October 31, 2002
    Inventors: Donald A. Northcut, Douglas W. Northcut
  • Patent number: 6423223
    Abstract: The present invention provides a multi-element filtering system assuring serial filtration of a liquid through multiple filter cartridges while enabling flushing without requiring removal of the filter cartridges. Both conventional and reverse osmosis filtration is performed, sequentially, within the system. The filter cartridges are held within a canister which is pressed against the cap and constrained against rotation with the cap. The canister is divided into chambers, and has passages in its floor arranged to enable serial transfer of liquid from one chamber to the next. Flushing employs liquid introduced under normal pressure. Passages leading to the flush liquid outlet enable flushing to proceed when the flush liquid outlet is opened. At other times, filtered liquid will pass through passages leading to the filtered liquid outlet. Liquid is circulated to assure filtration even when flushing, so that contamination of filtered liquid is precluded.
    Type: Grant
    Filed: February 21, 2001
    Date of Patent: July 23, 2002
    Inventors: Donald A. Northcut, Douglas W. Northcut
  • Publication number: 20020023865
    Abstract: The present invention provides a multi-element filtering system assuring serial filtration of a liquid through multiple filter cartridges while enabling flushing without requiring removal of the filter cartridges. Both conventional and reverse osmosis filtration is performed, sequentially, within the system. The filter cartridges are held within a canister which is pressed against the cap and constrained against rotation with the cap. The canister is divided into chambers, and has passages in its floor arranged to enable serial transfer of liquid from one chamber to the next. Flushing employs liquid introduced under normal pressure. Passages leading to the flush liquid outlet enable flushing to proceed when the flush liquid outlet is opened. At other times, filtered liquid will pass through passages leading to the filtered liquid outlet. Liquid is circulated to assure filtration even when flushing, so that contamination of filtered liquid is precluded.
    Type: Application
    Filed: February 21, 2001
    Publication date: February 28, 2002
    Inventors: Donald A. Northcut, Douglas W. Northcut
  • Patent number: 6027647
    Abstract: A filter housing assuring serial filtration of a liquid through plural filter cartridges and enabling flushing without requiring removal of the filter cartridges. The filter housing has a cap including a liquid inlet, a filtered liquid outlet, a flush liquid outlet, and internal passages. The filter cartridges are held within a canister which is pressed against the cap and constrained against rotation with the cap. A retaining member surrounding and bearing against the canister threads to the cap. The canister is divided into chambers, and has passages in its floor arranged to enable serial transfer of liquid from one chamber to the next. Flushing employs liquid introduced under normal pressure. Passages leading to the flush liquid outlet enable flushing to proceed when the flush liquid outlet is opened. At other times, filtered liquid will pass through passages leading to the filtered liquid outlet.
    Type: Grant
    Filed: May 20, 1998
    Date of Patent: February 22, 2000
    Inventors: Donald A. Northcut, Douglas W. Northcut