METAL RECOVERY UNIT

• US 3,616,412 A
• Filed: 09/25/1968
• Issued: 10/26/1971
• Est. Priority Date: 09/25/1968
• Status: Expired due to Term

• Current Assignee: Oliver W. Gnage
• Original Assignee: Oliver W. Gnage
• Inventors: Gnage, Oliver W.
• Primary Examiner(s): Mack, John H.
• Assistant Examiner(s): Valentine, D. R.
• Application Number:
  US04/762,386
• Time in Patent Office: 1,126 Days
• Field of Search: 204/228,275,195,231,109
• US Class Current: 204/402
• CPC Class Codes: G01N 27/42 Measuring deposition or liberation of materials from an electrolyte; Coulometry, i.e. measuring coulomb-equivalent of material in an electrolyte

Abstract

A coulometric device which may be used to determine the concentration of silver in solutions used in photography is disclosed. The device may be made an in-line part of a system for the recovery of such silver. The device is of simple rugged construction and utilizes for silver-determining purposes three electrically conductive probes which are housed within a chamber, such chamber having inlet and outlet orifices. One probe is situated near the inlet orifice; the other two probes are near each other, and near the outlet orifice. The first probe, and the second and third probes, are periodically reverse excited. Silver periodically builds up on the second and third probes, causing the resistance therebetween to lower periodically. The duration necessary to lower such resistance to a certain threshold level is proportional to silver concentration.

Claims

2. The device of claim 1 wherein said second and third eLectrically conductive means are spacially aligned with respect to each other.

3. The device of claim 2 wherein the part of at least one of said second and third electrically conductive means which is proximate the other of said means is tapered.

4. Apparatus responsive as a function of the concentration of silver in a solution, which apparatus is useful in combination with a system for the recovery of such silver, and which system includes, at least in part, means for conveying such solution from a source thereof to a silver recovery cell, comprising a. means disposed to receive at its input end said solution, and to convey said solution to said recovery cell from its output end, b. a first electrode disposed near the input end of said means, c. a second electrode electrically insulated from said first electrode and disposed near said output end of said means, d. an electrically conductive member which is electrically insulated from both said electrodes, said member being disposed proximate, but spaced apart from, said second electrode to form a gap between said electrode and said member, said gap having a predetermined nominal reference size, whereby when said first and second electrodes are respectively positively and negatively excited electrically, the gap between said second electrode and said member is diminished, with respect to its said nominal reference size by the deposition of silver on said second electrode, said deposition being at a rate that is proportional to the concentration of said silver within said fixing solution, e. means for simultaneously electrically exciting periodically said first electrode positively and said second electrode negatively for a predetermined duration, and for periodically reversing the polarities of said excitations, and f. means responsive, while said first and second electrodes are respectively positively and negatively excited, to changes in the electrical resistance which obtains between said second electrode and said conductive member for detecting the time that it takes for the deposition of silver on said second electrode to cause the resistance between said second electrode and said member to fall below a certain predetermined level, said time being proportional to the concentration of silver in said solution.

5. The apparatus of claim 4 wherein said member is an electrode which is also negatively excited when said first electrode is positively excited.

6. The apparatus of claim 5 wherein said second electrode and said member are both elongated and spacially disposed substantially end to end with respect to each other.