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39073Re: condensor

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  • Harry
    Apr 4, 2007
      --- In Distillers@yahoogroups.com, Trid <triddlywinks@...> wrote:

      with spacers in lieu of the expense of a reducing fitting.
      > Trid
      > -already putting my shopping list together for this rig

      Before you get too carried away, Trid. Your original answer was
      pretty solid, but you missed a couple of important points.
      Condensers efficiency has a few more quirks.

      5. Turbulence. Either or both of the fluids being turbulent is more
      efficient. Commonly it is accomplished by making sure there is
      something in the pathway of the vapour to force it to divert into
      the walls of the coolant carrier. It's automatic with coils as they
      are at rightangles to the vapour flowpath, and providing you put
      something in the centre space (like mesh) there's full turbulence.

      There's no such diversion in the proposed design, hence only the
      edges of the vapours contact the copper transfer walls, leaving the
      middle of the vapour to continue on (it's laminar flow, not
      turbulent). You 'may' get some turbulence with the descending
      condensate using the same path. You 'may' also get some hold-up of
      liquid in the condenser which could lead to problems. It's really
      a 'try it & see' situation (IOW, experiment). :)

      6. Flow direction. There's 3 basic types of condenser: Co-current
      (same direction of flow for both fluids), Counter-current (opposite
      directions, considered the most efficient of all) and Cross-current
      (fluids travel at rightangles to each other).

      In reality, most condensers are a combination of these. For
      instance the proposed design has both co-current and counter-
      current, therefore it's known as a multi-pass condenser (2 passes in
      this case).

      Coils are both crossflow (rightangles) and either co- or counter-
      current, depending on which way you feed the coolant, top or bottom

      Crossflows are most useful in high-volume and phase-change
      situations, like steam recovery and our little application.

      If you consider all of the above you will see why Liebig-style
      condensers need to be so big or long. No turbulence is the culprit.

      There's a paper in the Library that is useful to condenser designers.

      regards Harry
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