Lawrence B Friar from Yorklyn, DE

Recovery Of Silver From Photographic Processor Effluents
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US Patent:

42796440, Jul 21, 1981
Filed:

Jun 6, 1980
Appl. No.:

6/157456
Inventors:

Lawrence B. Friar - Yorklyn DE
Kenneth M. Smith - Newark DE
Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE
International Classification:

C22B 1104
US Classification:

75118P
Abstract:

Wash-off effluent from a photographic film processor is desilvered by a continuous process, employing the following sequence of steps: 1. Addition of anti-foaming agent. 2. Acidification. 3. Chemical reduction of ionic silver to metallic silver by sodium borohydride in alkaline solution. 4. Addition of one of more fluocculants. 5. Passage through hold-up tank to allow time for flow formation. 6. Filtration through automatic gravity filtration device or its equivalent. An apparatus for the treatment process is also provided.

Film Processor
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US Patent:

43279872, May 4, 1982
Filed:

Oct 22, 1980
Appl. No.:

6/196342
Inventors:

Lawrence B. Friar - Yorklyn DE
Noel H. Kuhrt - Wilmington DE
Joel L. Vanover - Elkton MD
Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE
International Classification:

G03D 504
US Classification:

354317
Abstract:

An apparatus for processing exposed photosensitive film sheets. A liquid used to develop the images on an exposed element as it is transported through the apparatus flows from a trough located above the path of transport. The liquid passes through a screen as it is introduced to and as it flows from the trough.