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Plastic jacketed condensers

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  • Trid
    My first condensers (Liebig style) were 1/2 copper tubing jacketed with 1 PVC. I capped the PVC tube and drilled/tapped holes in the side of each cap for
    Message 1 of 8 , Jul 3, 2007
      My first condensers (Liebig style) were 1/2" copper tubing jacketed with 1"
      PVC. I capped the PVC tube and drilled/tapped holes in the side of each cap
      for the inlet/outlet in order to use a barb fitting for coolant. I drilled a
      5/8" (the OD of the copper) hole in the end of each cap and sealed it with JB
      Weld (a metallic epoxy if you're not familiar). It sealed up very well and
      held pressure famously.

      However...
      When I fired up the rig, the heat of the vapors that it was designed to
      condense caused thermal expansion in the copper but not the PVC as the copper
      was in direct contact with the heat prior to reaching the coolant. This caused
      the JB Weld to crack and leaks to occur. I had attempted a stopgap fix by
      using silicone RTV, but as previously mentioned, the soft seal failed in the
      heat...more leaks.

      Plan B: All copper. That worked flawlessly, albeit expensively. Still, no
      worries about expansion due to mechanical strength of the sweat joints. Also,
      no danger of bumping or dropping it to crack the epoxy seals. But it was
      heavy, too.

      Plan C: My current favorite so far. I acquired some 3/8" (7/16" OD) copper
      tubing. I figured an arrangement of 7/16" holes to fit within the OD of a 2"
      copper cap...it worked out to be 14, in rows of 3,4,4, and 3 respectively,
      evenly spaced. I cut 14 sections of the 1/4" tubing 1 foot long, fit the ends
      into the holes in the cap and soldered from the inside of the cap. Repeat for
      the other side. From the side, it kinda looks like ]=====[ (but more rows
      than just two). I put a short nipple of 2" pipe on one side and a 45 degree
      elbow on the other side. I happened to have 4" ABS pipe on hand (though 3"
      would be just as good) and here's where the fun happened. Using two rubber
      reducers (4" to 2", of course) that attach with hose clamps, I attached the
      plastic shell to the copper tube bundle...voila! Instant shell and tube
      condenser. Repeat the drill/tap for coolant fittings. The beauty of the
      rubber reducers is that they flex with the thermal expansion of the copper and
      the hose clamp keeps a positive seal on both the copper *and* it allows for
      disassembly for whatever reason. Almost one year of service and it's not leaked
      a drop. Also, the tubes make for a huge improvement in surface area for
      condensation so the length can be much shorter than a single tube Liebig style
      condenser.

      If it's all confusing, I'll discombobulate it and take photos.

      Trid
      Hope this helps
    • mstehelin
      Is this similar to the coiless condenser in the photo section posted by whammo57? Please post a picture Cheers M ... with 1 ... each cap ... drilled a ... it
      Message 2 of 8 , Jul 3, 2007
        Is this similar to the coiless condenser in the photo section posted
        by whammo57?
        Please post a picture
        Cheers
        M

        --- In new_distillers@yahoogroups.com, Trid <triddlywinks@...> wrote:
        >
        > My first condensers (Liebig style) were 1/2" copper tubing jacketed
        with 1"
        > PVC. I capped the PVC tube and drilled/tapped holes in the side of
        each cap
        > for the inlet/outlet in order to use a barb fitting for coolant. I
        drilled a
        > 5/8" (the OD of the copper) hole in the end of each cap and sealed
        it with JB
        > Weld (a metallic epoxy if you're not familiar). It sealed up very
        well and
        > held pressure famously.
        >
        > However...
        > When I fired up the rig, the heat of the vapors that it was designed to
        > condense caused thermal expansion in the copper but not the PVC as
        the copper
        > was in direct contact with the heat prior to reaching the coolant.
        This caused
        > the JB Weld to crack and leaks to occur. I had attempted a stopgap
        fix by
        > using silicone RTV, but as previously mentioned, the soft seal
        failed in the
        > heat...more leaks.
        >
        > Plan B: All copper. That worked flawlessly, albeit expensively.
        Still, no
        > worries about expansion due to mechanical strength of the sweat
        joints. Also,
        > no danger of bumping or dropping it to crack the epoxy seals. But
        it was
        > heavy, too.
        >
        > Plan C: My current favorite so far. I acquired some 3/8" (7/16"
        OD) copper
        > tubing. I figured an arrangement of 7/16" holes to fit within the
        OD of a 2"
        > copper cap...it worked out to be 14, in rows of 3,4,4, and 3
        respectively,
        > evenly spaced. I cut 14 sections of the 1/4" tubing 1 foot long,
        fit the ends
        > into the holes in the cap and soldered from the inside of the cap.
        Repeat for
        > the other side. From the side, it kinda looks like ]=====[ (but
        more rows
        > than just two). I put a short nipple of 2" pipe on one side and a
        45 degree
        > elbow on the other side. I happened to have 4" ABS pipe on hand
        (though 3"
        > would be just as good) and here's where the fun happened. Using two
        rubber
        > reducers (4" to 2", of course) that attach with hose clamps, I
        attached the
        > plastic shell to the copper tube bundle...voila! Instant shell and tube
        > condenser. Repeat the drill/tap for coolant fittings. The beauty
        of the
        > rubber reducers is that they flex with the thermal expansion of the
        copper and
        > the hose clamp keeps a positive seal on both the copper *and* it
        allows for
        > disassembly for whatever reason. Almost one year of service and it's
        not leaked
        > a drop. Also, the tubes make for a huge improvement in surface area for
        > condensation so the length can be much shorter than a single tube
        Liebig style
        > condenser.
        >
        > If it's all confusing, I'll discombobulate it and take photos.
        >
        > Trid
        > Hope this helps
        >
      • dearknarl
        Hey Trid, Do you use it as a reflux condenser, or as a pot still/product condenser? In which case, is that what the 45 degree elbow is for? and what is the 2
        Message 3 of 8 , Jul 4, 2007
          Hey Trid,

          Do you use it as a reflux condenser, or as a pot still/product
          condenser? In which case, is that what the 45 degree elbow is for?
          and what is the 2" nipple for? If it was a reflux condenser, it would
          just slot right on top of a 2" column instead of a coil right?

          I was thinking of doing very similar, but using 21 6mm (~1/4") OD
          tubes instead of 14 larger ones like you. Does anyone know if I'd get
          any flooding at about 1.3kW if it was vertically mounted as a reflux
          condenser?

          Cheers,
          knarl.

          ------>snip<-------
          > Plan C: My current favorite so far. I acquired some 3/8" (7/16"
          OD) copper
          > tubing. I figured an arrangement of 7/16" holes to fit within the
          OD of a 2"
          > copper cap
          ------>snip<---------
          > than just two). I put a short nipple of 2" pipe on one side and a
          45 degree
          > elbow on the other side. I happened to have 4" ABS pipe on hand
          (though 3"
          > would be just as good) and here's where the fun happened. Using
          two rubber
          > reducers (4" to 2", of course) that attach with hose clamps, I
          attached the
          > plastic shell to the copper tube bundle...voila! Instant shell and
          tube
          > condenser.
        • Trid
          ... The simple answer is yes. I can use it as both. ... Yes again :) But wait, there s more... The 45 elbow allows it to connect to the 2 tee at the top
          Message 4 of 8 , Jul 5, 2007
            --- In new_distillers@yahoogroups.com, "dearknarl" <dearknarl@...> wrote:
            >
            > Hey Trid,
            >
            > Do you use it as a reflux condenser, or as a pot still/product
            > condenser?

            The simple answer is "yes." I can use it as both.

            > In which case, is that what the 45 degree elbow is for?
            > and what is the 2" nipple for? If it was a reflux condenser, it would
            > just slot right on top of a 2" column instead of a coil right?

            Yes again :) But wait, there's more...
            The 45 elbow allows it to connect to the 2" tee at the top of my pot
            still column. The tee sits sideways so the openings are
            top/bottom/side. The top is capped for my thermometer port, the side
            is effectively my lyne arm (only about 2" long) and the bottom fits
            into my column. The 45 at the end of my condenser slides on to the
            "lyne arm" and gravity holds it in place. Saran Wrap and other cling
            films are designed to withstand >=212F so I'm ok with using it to keep
            drips from happening at that joint. The 2" nipple at the other end is
            where I slide my reducing fitting on which ends in a 1/2" union which
            allows me to put any arrangement of elbows and tubing sections to
            reach my collection vessel...it's all modular so I can experiment with
            different physical configurations.

            However, as a reflux condenser, the nipple does exactly as you
            deduced...it fits into the top of the column. It's multi-functional :)

            I will try to get around to the photos I previously threatened to post
            earlier...hopefully tonight.

            > I was thinking of doing very similar, but using 21 6mm (~1/4") OD
            > tubes instead of 14 larger ones like you. Does anyone know if I'd
            > get
            > any flooding at about 1.3kW if it was vertically mounted as a reflux
            > condenser?

            I'd almost put money on the fact that it wouldn't get flooded at only
            1.3 kw. If you know the ID, figure the total area inside the tubes
            and compare that to that of other sized pipes...1/2", 3/4" etc.
            Remember also that with flooding you're considering the condensed
            liquid clogging things up. There's also the consideration of
            incomplete condensation...where you'd have vapor exiting your
            condenser. I would pretty much guarantee that with 21 tubes, if your
            length is 12" or greater you have no risk of that as long as coolant
            is flowing through the jacket.

            Trid
            -must remember to take photos
          • Harry
            ... , Trid wrote: I would pretty much guarantee that with 21 tubes, if your ... I ll vouch for
            Message 5 of 8 , Jul 5, 2007


              --- In new_distillers@yahoogroups.com, "Trid" <triddlywinks@...> wrote:
               I would pretty much guarantee that with 21 tubes, if your
              > length is 12" or greater you have no risk of that as long as coolant
              > is flowing through the jacket.
              >
              > Trid

               

              I'll vouch for that.  I use a crossflow (multi-tube) condenser as a reflux total condenser on top of the column.  It's got 19 tubes @ 6mm x 140mm ( 1/4" x 5 1/2" ) and it can handle 2000w with ease, at a 6 litre/minute water flow.

              The same configuration with the water & vapour reversed as in gatling gun style (which is what you're referring to) would handle similar but slightly less power input, due to laminar non-turbulent vapour flow in the tubes as opposed to rightangle impinging (it's an efficiency thing, way too complicated to easily explain).

              Double the overall length to 12" as Trid suggests and it would potentially handle about 3 to 3.5kW, depending on water flow rate.  The harder the power push, the more margin for inefficiencies you have to design in.  Suffice to say, 21 tubes @ 6mm x 300mm ( 1/4" x 12" ) in a gatling gun or multi-tube liebig configuration will condense just about anything you can produce from a 2" or even 3" column.

              This is the type of final product condenser used in modern eau-de-vie stills such as Christian Carl & Holstein.  The black arrow indicates the final condenser below...

               


              Slainte!
              regards Harry

            • dearknarl
              Thanks Trid and Harry, I already figured that the condensing power was plenty with that many pipes, and the summated cross sectional area is equivalent to at
              Message 6 of 8 , Jul 5, 2007
                Thanks Trid and Harry,

                I already figured that the condensing power was plenty with that many
                pipes, and the summated cross sectional area is equivalent to at least
                a 20mm ID pipe which wouldn't flood, but I was actually concerned
                about the surface tention of the liquid causing flooding or
                spluttering becasue of the smaller diameter pipes. What is the typical
                tube size that people use for shotgun/gattling gun condensers?

                Cheers,
                knarl.

                On 7/6/07, Harry <gnikomson2000@...> wrote:
                >
                >
                > --- In new_distillers@yahoogroups.com
                > <mailto:new_distillers@yahoogroups.com> , "Trid" <triddlywinks@...>
                > wrote:
                > I would pretty much guarantee that with 21 tubes, if your
                > > length is 12" or greater you have no risk of that as long as coolant
                > > is flowing through the jacket.
                > >
                > > Trid
                >
                >
                >
                > I'll vouch for that. I use a crossflow (multi-tube) condenser as a
                > reflux total condenser on top of the column. It's got 19 tubes @ 6mm x
                > 140mm ( 1/4" x 5 1/2" ) and it can handle 2000w with ease, at a 6
                > litre/minute water flow.
                >
                > The same configuration with the water & vapour reversed as in gatling
                > gun style (which is what you're referring to) would handle similar but
                > slightly less power input, due to laminar non-turbulent vapour flow in
                > the tubes as opposed to rightangle impinging (it's an efficiency thing,
                > way too complicated to easily explain).
                >
                > Double the overall length to 12" as Trid suggests and it would
                > potentially handle about 3 to 3.5kW, depending on water flow rate. The
                > harder the power push, the more margin for inefficiencies you have to
                > design in. Suffice to say, 21 tubes @ 6mm x 300mm ( 1/4" x 12" ) in a
                > gatling gun or multi-tube liebig configuration will condense just about
                > anything you can produce from a 2" or even 3" column.
                >
                > This is the type of final product condenser used in modern eau-de-vie
                > stills such as Christian Carl & Holstein. The black arrow indicates the
                > final condenser below...
                >
                >
                >
                >
                >
                >
                > Slainte!
                > regards Harry
                >
                >
              • Harry
                ... , dearknarl ... Well I don t know what the typical size is that people use, but I can tell you the
                Message 7 of 8 , Jul 5, 2007

                  --- In new_distillers@yahoogroups.com, dearknarl <dearknarl@...> wrote:

                  >
                  > Thanks Trid and Harry,
                  >
                  > I already figured that the condensing power was plenty with that many
                  > pipes, and the summated cross sectional area is equivalent to at least
                  > a 20mm ID pipe which wouldn't flood, but I was actually concerned
                  > about the surface tention of the liquid causing flooding or
                  > spluttering becasue of the smaller diameter pipes. What is the typical
                  > tube size that people use for shotgun/gattling gun condensers?
                  >
                  > Cheers,
                  > knarl.

                   

                  Well I don't know what the typical size is that people use, but I can tell you the correct size...6mm OD tube.

                  Reasons?  6mm tube is actually 6.35mm OD and 4.53mm ID with a 0.91mm wall thickness.  This 4.53mm inner diameter is the perfect size for liquid droplets to form and travel.  If you go much larger in bore size, you risk getting 'blow-by' of uncondensed vapours because the cooling effect reduces rapidly once you get past 2mm from the condensing surface ( the tube wall ).  Thus a 4.53mm bore is right for bigger (relatively) liquid droplets and almost perfect to eradicate blow-by. 

                  There won't be (or shouldn't be) any vapour pressure forcing the liquid out of the tubes because as you have already discovered, the combined area of 21 tubes is quite large.

                  Area of a circle is Pi times radius squared ( ð r² ).

                  3.1416 x (½ x 4.53)² = 16 sq.mm

                  By 21 tubes = 16 x 21 = 336 sq.mm

                  That's about equal to a single 22mm OD tube with a 0.91 wall.

                  Because the condenser is in a vertical or 45° downward configuration, gravity should take care of any surface tension of the liquid in the tube bores.  If in doubt, test it with a cup of water poured in the top end vapour side.  You'll see it readily runs through.

                  Slainte!
                  regards Harry

                • dearknarl
                  Harry, The more I think about it, the less I think the tubes would get flooded. Even at 80ml per min condensate, that s less than 4ml per min for each tube,
                  Message 8 of 8 , Jul 5, 2007
                    Harry,

                    The more I think about it, the less I think the tubes would get
                    flooded. Even at 80ml per min condensate, that's less than 4ml per min
                    for each tube, and at a guess that's one or two drips per second,
                    which would only be a trickle on the inside of the tubes - nothing
                    that's going to stop rising vapor.

                    Cheers,
                    knarl.

                    On 7/6/07, Harry <gnikomson2000@...> wrote:
                    >
                    > --- In new_distillers@yahoogroups.com
                    > <mailto:new_distillers@yahoogroups.com> , dearknarl <dearknarl@...>
                    > wrote:
                    > >
                    > > Thanks Trid and Harry,
                    > >
                    > > I already figured that the condensing power was plenty with that many
                    > > pipes, and the summated cross sectional area is equivalent to at least
                    > > a 20mm ID pipe which wouldn't flood, but I was actually concerned
                    > > about the surface tention of the liquid causing flooding or
                    > > spluttering becasue of the smaller diameter pipes. What is the typical
                    > > tube size that people use for shotgun/gattling gun condensers?
                    > >
                    > > Cheers,
                    > > knarl.
                    >
                    >
                    >
                    > Well I don't know what the typical size is that people use, but I can
                    > tell you the correct size...6mm OD tube.
                    >
                    > Reasons? 6mm tube is actually 6.35mm OD and 4.53mm ID with a 0.91mm
                    > wall thickness. This 4.53mm inner diameter is the perfect size for
                    > liquid droplets to form and travel. If you go much larger in bore size,
                    > you risk getting 'blow-by' of uncondensed vapours because the cooling
                    > effect reduces rapidly once you get past 2mm from the condensing surface
                    > ( the tube wall ). Thus a 4.53mm bore is right for bigger (relatively)
                    > liquid droplets and almost perfect to eradicate blow-by.
                    >
                    > There won't be (or shouldn't be) any vapour pressure forcing the liquid
                    > out of the tubes because as you have already discovered, the combined
                    > area of 21 tubes is quite large.
                    >
                    > Area of a circle is Pi times radius squared ( ð r² ).
                    >
                    > 3.1416 x (½ x 4.53)² = 16 sq.mm
                    >
                    > By 21 tubes = 16 x 21 = 336 sq.mm
                    >
                    > That's about equal to a single 22mm OD tube with a 0.91 wall.
                    >
                    > Because the condenser is in a vertical or 45° downward configuration,
                    > gravity should take care of any surface tension of the liquid in the
                    > tube bores. If in doubt, test it with a cup of water poured in the top
                    > end vapour side. You'll see it readily runs through.
                    >
                    > Slainte!
                    > regards Harry
                    >
                    >
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