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Re: Auto Feed Control

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  • abbababbaccc
    The mash doesn t boil away. When the boiling event starts at the bottom the pipe, the pipe will burp out mash to the top of the packing. This means that
    Message 1 of 9 , Nov 9, 2008
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      The mash doesn't boil away. When the boiling event starts at the
      bottom the pipe, the pipe will "burp" out mash to the top of the
      packing. This means that there will be some room left in the pipe and
      cold mash will flow in and the boiling ceases. It gets heated,
      another burp and the cycle continues. This will result a continuous
      feed of mash to the top of the packing as long as the temperature at
      the lower parts of the column is adequate. When the bottom of the
      column cools down the cycle will stop, which is a good thing as
      otherwise you'd be getting alcohol out from the boiler overflow. When
      the cycle stops the column bottom starts to warm again and on we go
      with burping :)

      You could experiment with preheating of course but it is not
      necessary for this setup and could actually alter this burping
      behaviour.

      If you have trouble understanding this burping thing get a piece of
      pipe with closed bottom, fill it with water and apply some heat to
      the bottom. When the boiling starts it will spill out a considerable
      amount of liquid.

      Cheers, Riku

      --- In Distillers@yahoogroups.com, "Rob Macrobert" <macrobert@...>
      wrote:
      >
      >
      > Morning folks, I've been looking at Riku's description of AFC, as
      well as some of the rigs on the forum, and I must admit to being
      completely baffled on a couple of points.
      > If I am understanding the process correctly on a VM rig,
      > -The feed tube fills with wash
      > -As the feed tube heats up, the alcohol boils off and the vapors
      cycle in the column until the ABV hits ~40-45% where it can "fall"
      out the take off tube.
      >
      > But, how does the tube refill with fresh wash? It looks to me, that
      we have to wait for what remains in the tube to boil off before the
      fresh charge can enter, and that would give us what Harry and the
      other knowledgeable ones have been saying is a VERY BAD THING, surge
      boiling.
      > Based on that, if the wash is preheated to 40-50C before
      introduction, would that smooth out the surges and be an improvement?
      Or is this the type of thing where you use an undesirable to prevent
      worse things from happening? Such as choking or overloading.
      >
      > Or is my understanding of the process completely wrong and I'm
      making it out to be more complicated than it needs to be?
      >
      > If someone could explain this one to me, it would be greatly
      appreciated.
      >
      > Robbie Mac
      >
      >
      >
      >
      >
      >
      >
      >
      >
      >
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    • Rob Macrobert
      Thanks Riku, it makes more sense now, As I haven t seen any recommended sizing for the feed pipe -vs- wattage supplied, I would have to think that the cycle
      Message 2 of 9 , Nov 9, 2008
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        Thanks Riku, it makes more sense now,

        As I haven't seen any recommended sizing for the feed pipe -vs- wattage supplied, I would have to think that the cycle between burps is a variable that might be improved on by preheating.
        Or would it be likely to result in overloading the packing with more liquid than could be dealt with, with out more heat applied, bringing us full circle?
        Any thoughts?

        I have an air cooled, VM continuous, stripping column operating now, without AFC, and stopping it from choking is a bit of a chore at times. So I am very interested in figuring out if AFC will give me the control I'm looking for, without sacrificing output.

        BTW, love your book, but there are a couple of areas that seem to be lacking some of the in depth background information that is in other areas, such as sizing for air cooling, and how AFC works. <GR>

        Cheers,
        Robbie Mac



        ----- Original Message -----
        From: abbababbaccc
        To: Distillers@yahoogroups.com
        Subject: [Distillers] Re: Auto Feed Control
        Date: Sun, 09 Nov 2008 16:12:22 -0000





        The mash doesn't boil away. When the boiling event starts at the
        bottom the pipe, the pipe will "burp" out mash to the top of the
        packing. This means that there will be some room left in the pipe and
        cold mash will flow in and the boiling ceases. It gets heated,
        another burp and the cycle continues. This will result a continuous
        feed of mash to the top of the packing as long as the temperature at
        the lower parts of the column is adequate. When the bottom of the
        column cools down the cycle will stop, which is a good thing as
        otherwise you'd be getting alcohol out from the boiler overflow. When
        the cycle stops the column bottom starts to warm again and on we go
        with burping :)

        You could experiment with preheating of course but it is not
        necessary for this setup and could actually alter this burping
        behaviour.

        If you have trouble understanding this burping thing get a piece of
        pipe with closed bottom, fill it with water and apply some heat to
        the bottom. When the boiling starts it will spill out a considerable
        amount of liquid.

        Cheers, Riku






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      • abbababbaccc
        AFC is not my invention and I haven t tried one yet so I didn t write about it either. However, the concept is tested by Nykter and it works very well. IIRC
        Message 3 of 9 , Nov 9, 2008
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          AFC is not my invention and I haven't tried one yet so I didn't write
          about it either. However, the concept is tested by Nykter and it
          works very well. IIRC nykter had 8mm or 10mm feed pipe and 1kW
          heating element in a 2" continuous stripper.

          Preheating should indeed work as long as it's not getting heated too
          close to boiling point. Once you are very close to boiling the
          boiling event may start in too large area and cause burping back to
          reservoir and slow down the refilling of the tube. Just a theory but
          I'd be cautious.

          Aircooling, for copper pipe you can calculate the ambient cooling
          based on values that match real life examples. For convector pipes
          that get's really complicated and when you start using fans the math
          is IMO too complicated to present real life with any accuracy. Thus I
          took few examples one could use for most common still sizes. Granted
          I could have used more examples but I didn't have that many of them
          available :(

          If you are worried about AFC you could always use a solenoid valve
          for feed control and apply the principles presented in E-ARC chapter
          for control. Only this time you want to keep the temperature at the
          bottom of the column at 100C.

          Cheers, Riku


          --- In Distillers@yahoogroups.com, "Rob Macrobert" <macrobert@...>
          wrote:
          >
          > Thanks Riku, it makes more sense now,
          >
          > As I haven't seen any recommended sizing for the feed pipe -vs-
          wattage supplied, I would have to think that the cycle between burps
          is a variable that might be improved on by preheating.
          > Or would it be likely to result in overloading the packing with
          more liquid than could be dealt with, with out more heat applied,
          bringing us full circle?
          > Any thoughts?
          >
          > I have an air cooled, VM continuous, stripping column operating
          now, without AFC, and stopping it from choking is a bit of a chore at
          times. So I am very interested in figuring out if AFC will give me
          the control I'm looking for, without sacrificing output.
          >
          > BTW, love your book, but there are a couple of areas that seem to
          be lacking some of the in depth background information that is in
          other areas, such as sizing for air cooling, and how AFC works. <GR>
          >
          > Cheers,
          > Robbie Mac
          >
          >
          >
          > ----- Original Message -----
          > From: abbababbaccc
          > To: Distillers@yahoogroups.com
          > Subject: [Distillers] Re: Auto Feed Control
          > Date: Sun, 09 Nov 2008 16:12:22 -0000
          >
          >
          >
          >
          >
          > The mash doesn't boil away. When the boiling event starts at the
          > bottom the pipe, the pipe will "burp" out mash to the top of the
          > packing. This means that there will be some room left in the pipe
          and
          > cold mash will flow in and the boiling ceases. It gets heated,
          > another burp and the cycle continues. This will result a continuous
          > feed of mash to the top of the packing as long as the temperature
          at
          > the lower parts of the column is adequate. When the bottom of the
          > column cools down the cycle will stop, which is a good thing as
          > otherwise you'd be getting alcohol out from the boiler overflow.
          When
          > the cycle stops the column bottom starts to warm again and on we go
          > with burping :)
          >
          > You could experiment with preheating of course but it is not
          > necessary for this setup and could actually alter this burping
          > behaviour.
          >
          > If you have trouble understanding this burping thing get a piece of
          > pipe with closed bottom, fill it with water and apply some heat to
          > the bottom. When the boiling starts it will spill out a
          considerable
          > amount of liquid.
          >
          > Cheers, Riku
          >
          >
          >
          >
          >
          >
          > --
          > Be Yourself @ mail.com!
          > Choose From 200+ Email Addresses
          > Get a Free Account at www.mail.com
          >
        • mavnkaf
          ... well as some of the rigs on the forum, and I must admit to being completely baffled on a couple of points. ... cycle in the column until the ABV hits
          Message 4 of 9 , Nov 9, 2008
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            --- In Distillers@yahoogroups.com, "Rob Macrobert" <macrobert@...>
            wrote:
            >
            >
            > Morning folks, I've been looking at Riku's description of AFC, as
            well as some of the rigs on the forum, and I must admit to being
            completely baffled on a couple of points.
            > If I am understanding the process correctly on a VM rig,
            > -The feed tube fills with wash
            > -As the feed tube heats up, the alcohol boils off and the vapors
            cycle in the column until the ABV hits ~40-45% where it can "fall"
            out the take off tube.
            >
            > But, how does the tube refill with fresh wash? It looks to me, that
            we have to wait for what remains in the tube to boil off before the
            fresh charge can enter, and that would give us what Harry and the
            other knowledgeable ones have been saying is a VERY BAD THING, surge
            boiling.
            > Based on that, if the wash is preheated to 40-50C before
            introduction, would that smooth out the surges and be an improvement?
            Or is this the type of thing where you use an undesirable to prevent
            worse things from happening? Such as choking or overloading.
            >
            > Or is my understanding of the process completely wrong and I'm
            making it out to be more complicated than it needs to be?
            >
            > If someone could explain this one to me, it would be greatly
            appreciated.
            >
            > Robbie Mac
            >
            ......................................................


            --- In Distillers@yahoogroups.com, "Rob Macrobert" <macrobert@...>
            wrote:
            >
            >
            > Morning folks, I've been looking at Riku's description of AFC, as
            well as some of the rigs on the forum, and I must admit to being
            completely baffled on a couple of points.
            > If I am understanding the process correctly on a VM rig,
            > -The feed tube fills with wash
            > -As the feed tube heats up, the alcohol boils off and the vapors
            cycle in the column until the ABV hits ~40-45% where it can "fall"
            out the take off tube.
            >
            > But, how does the tube refill with fresh wash? It looks to me, that
            we have to wait for what remains in the tube to boil off before the
            fresh charge can enter, and that would give us what Harry and the
            other knowledgeable ones have been saying is a VERY BAD THING, surge
            boiling.
            > Based on that, if the wash is preheated to 40-50C before
            introduction, would that smooth out the surges and be an improvement?
            Or is this the type of thing where you use an undesirable to prevent
            worse things from happening? Such as choking or overloading.
            >
            > Or is my understanding of the process completely wrong and I'm
            making it out to be more complicated than it needs to be?
            >
            > If someone could explain this one to me, it would be greatly
            appreciated.
            >
            Robbie Mac



            Hi Robbie,

            I made a AFC pot still a little while ago using Riku's advice, it
            worked first go with no real problems, it made a constant 50%
            distillate which is what I was aiming for. I used it as a stripping
            still for making rum.

            Preheating the wash will speed things up, but I have not tried it; my
            wash was at shed temp 25-30 C.

            Where you asked, "how does the tube refill with fresh wash?" The AFC
            external tube gets feed by the lower tank, as the heated wash "burps"
            or over flows into the copper packing new wash is introduced from the
            feeder tank, it's a continuous process. By using an inline valve you
            can control how fast (limited), or how slow you want the process to
            happen.

            I constantly checked the temp gauge at the bottom of the column to
            see if I'm going too fast, in my case, the optimum wash flow/
            distillate flow/bottom temp was 99.4 C but I can't remember the
            atmospheric pressure at the time but I was doing this @ 262 ft above
            sea level.

            To further answer the question about feeding the AFC tube, I used a
            two-tier tank setup, one tank higher than the other; the top tank
            feeds the lower tank via a float valve. That way the lower tank wash
            level remains constant thus pressure is constant, so the inline valve
            to control the wash flow rate would not change too much.

            My prototype AFC stripping still, using Riku's advice was not fast or
            really efficient but it did work how I thought it should or how I
            wanted it. When tested it I put 50 liters though it, which took
            about 8 hours from start up to finish, (I fiddle too much). It would
            have taken 5 hours if knew the optimum setting also I was using an
            1100 watt element too!!

            I know people would say I was not really stripping the wash, but on a
            test run I had to take it easy. Now I know how works I can see the
            time to strip a 50 liter wash down to 3 hours max, using a 2400 watt
            element. I hope my convoluted dribble helps. I think any words on
            the topic will help, as it will be recorded, right or wrong.

            Cheers
            Marc

            Btw sorry if have gone over what Riku had said or bad grammar and
            every thing else. Check the pictures out; they may explain what I
            was going on about. Look at the 5 pictures, if you need construction
            pic's let me know.

            http://tinyurl.com/555rkl
          • Rob Macrobert
            Thanks Riku, When I selected my convection tubes, I used the chart for a product called Slant Fin, which gave me 1Kw/m @ 180F vapor temp with a 20C ambient.
            Message 5 of 9 , Nov 10, 2008
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              Thanks Riku,
              When I selected my convection tubes, I used the chart for a product called Slant Fin, which gave me 1Kw/m @ 180F vapor temp with a 20C ambient.
              Considering I'm using a pair of 1.3 meter tubes on a 1Kw boiler @ 4-9C ambient, I'm good there.

              I'll give it a try with the preheat, as it's a cheap trial (thrift shop coffee maker) and see what happens if it doesn't work, it will be simple to remove.

              Cheers,



              ----- Original Message -----
              From: abbababbaccc
              To: Distillers@yahoogroups.com
              Subject: [Distillers] Re: Auto Feed Control
              Date: Mon, 10 Nov 2008 05:25:17 -0000





              AFC is not my invention and I haven't tried one yet so I didn't write
              about it either. However, the concept is tested by Nykter and it
              works very well. IIRC nykter had 8mm or 10mm feed pipe and 1kW
              heating element in a 2" continuous stripper.

              Preheating should indeed work as long as it's not getting heated too
              close to boiling point. Once you are very close to boiling the
              boiling event may start in too large area and cause burping back to
              reservoir and slow down the refilling of the tube. Just a theory but
              I'd be cautious.

              Aircooling, for copper pipe you can calculate the ambient cooling
              based on values that match real life examples. For convector pipes
              that get's really complicated and when you start using fans the math
              is IMO too complicated to present real life with any accuracy. Thus I
              took few examples one could use for most common still sizes. Granted
              I could have used more examples but I didn't have that many of them
              available :(

              If you are worried about AFC you could always use a solenoid valve
              for feed control and apply the principles presented in E-ARC chapter
              for control. Only this time you want to keep the temperature at the
              bottom of the column at 100C.

              Cheers, Riku



              --
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              Choose From 200+ Email Addresses
              Get a Free Account at www.mail.com
            • Rob Macrobert
              Sounds good Marc, right now I m running a constant feed that does 30L in about 3-4 hours, but with the occasional choking issue leaving it alone even long
              Message 6 of 9 , Nov 10, 2008
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                Sounds good Marc, right now I'm running a constant feed that does 30L in about 3-4 hours, but with the occasional choking issue leaving it alone even long enough to have a leak is not a good idea.
                I'm going to give AFC a try with a preheated wash and see what happens.
                BTW, what size feed tube and column are you running?
                Cheers,


                Robbie Mac
                Sometime tinkerer and sometimes it even works....

                ----- Original Message -----
                From: mavnkaf
                To: Distillers@yahoogroups.com
                Subject: [Distillers] Re: Auto Feed Control
                Date: Mon, 10 Nov 2008 07:31:06 -0000






                Hi Robbie,

                I made a AFC pot still a little while ago using Riku's advice, it
                worked first go with no real problems, it made a constant 50%
                distillate which is what I was aiming for. I used it as a stripping
                still for making rum.

                Preheating the wash will speed things up, but I have not tried it; my
                wash was at shed temp 25-30 C.

                Where you asked, "how does the tube refill with fresh wash?" The AFC
                external tube gets feed by the lower tank, as the heated wash "burps"
                or over flows into the copper packing new wash is introduced from the
                feeder tank, it's a continuous process. By using an inline valve you
                can control how fast (limited), or how slow you want the process to
                happen.

                I constantly checked the temp gauge at the bottom of the column to
                see if I'm going too fast, in my case, the optimum wash flow/
                distillate flow/bottom temp was 99.4 C but I can't remember the
                atmospheric pressure at the time but I was doing this @ 262 ft above
                sea level.

                To further answer the question about feeding the AFC tube, I used a
                two-tier tank setup, one tank higher than the other; the top tank
                feeds the lower tank via a float valve. That way the lower tank wash
                level remains constant thus pressure is constant, so the inline valve
                to control the wash flow rate would not change too much.

                My prototype AFC stripping still, using Riku's advice was not fast or
                really efficient but it did work how I thought it should or how I
                wanted it. When tested it I put 50 liters though it, which took
                about 8 hours from start up to finish, (I fiddle too much). It would
                have taken 5 hours if knew the optimum setting also I was using an
                1100 watt element too!!

                I know people would say I was not really stripping the wash, but on a
                test run I had to take it easy. Now I know how works I can see the
                time to strip a 50 liter wash down to 3 hours max, using a 2400 watt
                element. I hope my convoluted dribble helps. I think any words on
                the topic will help, as it will be recorded, right or wrong.

                Cheers
                Marc

                Btw sorry if have gone over what Riku had said or bad grammar and
                every thing else. Check the pictures out; they may explain what I
                was going on about. Look at the 5 pictures, if you need construction
                pic's let me know.

                http://tinyurl.com/555rkl


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                Choose From 200+ Email Addresses
                Get a Free Account at www.mail.com
              • mavnkaf
                ... 30L in about 3-4 hours, but with the occasional choking issue leaving it alone even long enough to have a leak is not a good idea. ... happens. ... Ruki
                Message 7 of 9 , Nov 10, 2008
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                  --- In Distillers@yahoogroups.com, "Rob Macrobert" <macrobert@...>
                  wrote:
                  >
                  > Sounds good Marc, right now I'm running a constant feed that does
                  30L in about 3-4 hours, but with the occasional choking issue leaving
                  it alone even long enough to have a leak is not a good idea.
                  > I'm going to give AFC a try with a preheated wash and see what
                  happens.
                  > BTW, what size feed tube and column are you running?
                  > Cheers,
                  >
                  >

                  Ruki suggested 8 mm or 10 mm, I went with the 8 mm feed tube with no
                  problems, the column is 50 mm x 110 cm, fully packed with copper
                  mesh. As you saw in my pictures I used a 20 litre coffee urn which
                  really lent it self to the job.

                  Cheers
                  Marc

                  btw, I'll add some construction pics later
                • mavnkaf
                  Ooppps, sorry Riku, I just mispelt your name. Cheers Marc
                  Message 8 of 9 , Nov 10, 2008
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                    Ooppps, sorry Riku, I just mispelt your name.

                    Cheers
                    Marc

                    > Ruki suggested 8 mm or 10 mm, I went with the 8 mm feed tube with no
                    > problems
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