Method and apparatus for recovering silver and plastic from used film
AssigneeKenmartin Development, Inc.
InventorKenneth M. Grout
Life of this patent
Estimating the term…
Abstract
A method and machine for recovering silver and polyester from exposed photographic X-ray film of the type having a polyester base coated with a sheath of polyvinyladine chloride and a photosensitive silver emulsion. Sheets of the film are fed through baths of hot caustic which successively remove the silver emulsion and deposit it as a sludge from which the silver is recovered and remove the polyvinyladine coating to permit the polyester to be recovered in a commercially acceptable pure form. Where the film sheets may include some acetate based film, the apparatus will distinguish between the polyester and acetate and discard the acetate bases as scrap, after the silver emulsion has been removed.
Claims10
The method of recovering silver and polyester from photographic film of the type comprising a polyester base having a surface coating which provides adhesion for a silver emulsion layer on said surface coating, said method comprising:
- (a) passing the film through a bath of a material which will attack the silver emulsion layer until it separates from the film and deposits as a sludge in said bath;
- (b) removing said sludge from said bath;
- (c) separating the solid silver containing particles of said sludge from the liquid portion of said sludge,
- (d) passing the film, cleansed of said silver emulsion, through a second bath of a material which will attack and remove said surface coating from said polyester base;
- (e) restraining said film from having any portion of its surface coming into contact with any other film surface throughout its travel through said baths, whereby any agglomeration of film is avoided;
- and
- (f) removing said cleansed polyester from said second bath;
- (g) whereby said silver containing particles and said cleansed polyester constitute the desired valuable recovery products.
An apparatus for recovering silver and polyester from a photographic film of the type having a polyester base having a surface coating which provides adhesion for a silver emulsion layer on said surface coating, comprising:
- (a) a bath of a material which will attack and remove the silver emulsion layer from said film,
- (b) means for feeding said film into said bath;
- (c) means for guiding said film through said bath along a path of sufficient length so that the time of travel through said bath is sufficient to cause said bath to substantially completely remove said emulsion from said film and deposit it as a sludge in said tank;
- (d) means for removing said sludge from said tank and for separating the solid silver containing particles of said sludge from its liquid portion, whereby said separated solid particles may be used as a valuable recovery product;
- (e) a second bath of a material which will attack and remove said surface coating from said polyester base;
- (f) means for feeding said film, cleansed of said silver emulsion, into said second bath;
- (g) means for guiding said film through said second bath along a path of sufficient length to cause said bath to substantially completely remove said surface coating from said polyester base;
- (h) means for leading said polyester base, cleansed of said surface coating, out of said second bath as a second valuable recovery product;
- (i) each of said guiding means being constructed and adapted to restrain said film from coming into contact with any other film surface, whereby agglomeration of said film is prevented.
Dependencies are inferred from the claim text.