Patents by Inventor Paul H. Whitney

Paul H. Whitney 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: 5202228
    Abstract: Silver sulfide is reversed in a process for regenerating a dissolved silver-containing spent bleach fixer solution. The process is particularly suited for treating the bleach fixer solution in a manner which enables recycling of the solution giving rise to considerable reduction in cost of bleach fixer solution and reduced environmental pollution. The process comprises introducing a hydrosulfide reagent into the bleach fixer solution, which contains silver, to precipitate silver sulfide while maintaining pH and thiosulfate levels in the bleach fixer to allow for reuse. The precipitate is isolated from the bleach fixer solution to remove silver thereby and hence enable recycling of the bleach fixer solution. It is preferred to adjust the pH and sulfite levels following silver removal to complete the regeneration process.
    Type: Grant
    Filed: August 9, 1991
    Date of Patent: April 13, 1993
    Assignee: Technology Transfer Barbados Inc.
    Inventors: Michael E. Dutka, Paul H. Whitney, Keith E. Malcolm