Emulsion Scaling

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Photo Engineer, Aug 25, 2006.

  1. Photo Engineer

    Photo Engineer Subscriber

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    Well, here is where the rubber hits the road.

    If you make an emulsion in your lab, and you add 1 liter in 1 minute (1 liter / minute), of silver and salt, and then scale up from 10 liters to 1000 liters what must you do?

    It requires the addition of 100 liters / minute of salt and silver.

    Can you imagine the pump speed and mixer speed?

    This was my specialty for about 15 years!

    And the answer is......

    Well, I'm in a mood to just leave this one hanging and let you think about it.

    PE
     
    Last edited by a moderator: Aug 26, 2006
  2. Aggie

    Aggie Member

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    aww just get a larger industrial size stop cock buret don't trust my spelling of the afore mentioned) and do several at once in various spots over what I would use is an industrial sized (thinking of Mrs. Fields type) Kitchenaid mixer. turn them on adjust the flow of the stuff going into the big mixer, and let er rip. Sorry just drinking my morning protein and I couldn't resist this.
     
  3. Photo Engineer

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    Aggie;

    Your solution does not work with modern emulsions, but might work with old fashioned emulsions as described in the other thread.

    Two things to consider though...

    Mixing and Enthalpy. Remember those?

    PE
     
  4. Aggie

    Aggie Member

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    OK how about a closed system where the liquid is injected, keping the temps constant? You could have a series of inlets from various containers to the main mixing chamber that is rotated to mix it all?
     
  5. Photo Engineer

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    That is pretty close to the key patent by Wey and Whiteley.

    It can work, but requires an exit port big enough to handle the outflow. In addition, it will only work for the first step. The hardware has to be entirely different for the rest of the steps.

    Basically, it is easier and less expensive to redesign the emulsion in many cases. But again, back to W&W, there are key emulsions that cannot be made any other way.

    Therefore, equipment can be huge and complex.

    BTW, temps cannot be 'constant'. Each ingredient must have a given temp or a ramped temp due to enthalpy. Otherwise the pot boileth over! And boiled gelatin sure does make a mess.

    PE
     
  6. Aggie

    Aggie Member

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    Why not several pressuried exits, that then could cool or be heated to the next stage for the chemical mixing? I'm just seat of my pants guessing about all of this. I'm no engineer and only made it through 400 level chemistry college classes. I never went on to seek masters or further in it. Seems a combo of endothermic and exothermic mixing chambers would help to solve many of the problems. Then if you are not mixing the big batches this could all be scaled down to a smaller operation. Again pure speculation.
     
  7. Photo Engineer

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    I'm sure that all of what you describe will work as it is similar to the main and ancillary patented methods.

    PE
     
  8. Neanderman

    Neanderman Member

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    Can you share patent numbers?
     
  9. Photo Engineer

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    It would be useless to try it, unless you have a large facility with process control computers. You can surely look it up yourself though if you are that interested. It is under the authors and assigned to Kodak.

    Since I know both of them personally and worked on the project, I don't need to keep a copy handy here. Sorry.

    PE