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Re:Temperature Controlers

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  • Firefox
    You will need an infinitely variable power controller. It sounds like the model you quote has a relay. If this is the case this unit will not give a constant
    Message 1 of 23 , Mar 3, 2008
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      You will need an infinitely variable power controller. It sounds like the model you quote has a relay. If this is the case this unit will not give a constant flow of vapour.

      Bob.

    • Caleb Dunstan
      Hi, I m a newbie, and have not actually built my still yet, but why not just use a simple PID controller and a K-type thermocouple for control, and hook that
      Message 2 of 23 , Mar 3, 2008
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        Hi,

         

        I'm a newbie, and have not actually built my still yet, but why not just use a simple PID controller and a K-type thermocouple for control, and hook that up to an SSR which is feeding your heating element. That would give you the range and sensitivity, and most of the PID's I've seen will give you control to about 0.1 of a deg C.  That's what we put on our espresso machine, and it works a treat.

         

         

         

         



        ----- Original Message ----
        From: Firefox <foxyfoxy50@...>
        To: Distillers@yahoogroups.com
        Sent: Monday, March 3, 2008 11:02:52 PM
        Subject: [Distillers] Re:Temperature Controlers

        You will need an infinitely variable power controller. It sounds like the model you quote has a relay. If this is the case this unit will not give a constant flow of vapour.

        Bob.




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      • Harry
        ... just use a simple PID controller and a K-type thermocouple for control, and hook that up to an SSR which is feeding your heating element. That would give
        Message 3 of 23 , Mar 3, 2008
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          --- In Distillers@yahoogroups.com, Caleb Dunstan <phantompower@...>
          wrote:
          >
          > Hi,
          >
          > I'm a newbie, and have not actually built my still yet, but why not
          just use a simple PID controller and a K-type thermocouple for
          control, and hook that up to an SSR which is feeding your heating
          element. That would give you the range and sensitivity, and most of
          the PID's I've seen will give you control to about 0.1 of a deg C.
          That's what we put on our espresso machine, and it works a treat.



          You're missing the point. You're wasting your time using head vapour
          temperature as the trigger because you don't want it fluctuating AT
          ALL in distillation. We're not simmering coffee here. Temperature
          does NOT need to be controlled. The composition of the vapour at the
          head will automatically decide the temperature recordable there. It
          is POWER INPUT that needs to be controlled. This is done with a
          burst-fire zero-switching controller. Slow on-off-on switches like
          stove controllers will only cause surge boiling, as will your setup.
          This destroys the two-way distilling action in the column.

          Do not confuse the two terms 'temperature' and 'power'. Temperature
          is the result of work done. Power is the work units applied.

          Slainte!
          regards Harry
          http://distillers.tastylime.net/library/
        • Trid
          ... On the surface, this sounds good, even with keeping within 0.1 C tolerance. In the case of coffee, hot water boilers, ovens, and the like, it s a really
          Message 4 of 23 , Mar 3, 2008
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            > --- In Distillers@yahoogroups.com, Caleb Dunstan <phantompower@...>
            > > I'm a newbie, and have not actually built my still yet, but why not
            > just use a simple PID controller and a K-type thermocouple for
            > control, and hook that up to an SSR which is feeding your heating
            > element. That would give you the range and sensitivity, and most of
            > the PID's I've seen will give you control to about 0.1 of a deg C.
            > That's what we put on our espresso machine, and it works a treat.

            On the surface, this sounds good, even with keeping within 0.1 C tolerance. In
            the case of coffee, hot water boilers, ovens, and the like, it's a really
            precise, well controlled situation. For what we're doing, not so much.

            Actually, the only flaw in how this operates is your solid state relay (SSR).
            Not that it doesn't hold temperature well, but because it holds it by turning
            the heat on and off (for people less familiar, a relay is just a switch that's
            operated electrically instead of by hand). Even on such a small scale as
            needed to maintain 0.1 degree stability, it's still a matter of on/off...just
            more rapid.

            --- Harry <gnikomson2000@...> wrote:
            > You're missing the point. You're wasting your time using head vapour
            > temperature as the trigger because you don't want it fluctuating AT
            > ALL in distillation. We're not simmering coffee here. Temperature
            > does NOT need to be controlled. The composition of the vapour at the
            > head will automatically decide the temperature recordable there. It
            > is POWER INPUT that needs to be controlled. This is done with a
            > burst-fire zero-switching controller. Slow on-off-on switches like
            > stove controllers will only cause surge boiling, as will your setup.
            > This destroys the two-way distilling action in the column.

            Where this is a more frequently seen application, such as stovetops and such,
            this is still the principle that you're working against (not with) when
            utilizing either infinite switches (such as stovetops) or SSRs (PID controlled
            or not) or any other on/off switching device.

            Controlling a reflux rig is actually much simpler than something that would
            demand a PID controller, although one could make it complicated enough to apply
            it. You need a steady input of power, or heat. It needs to be variable in the
            sense that you can adjust the steady input up or down...but when it goes up or
            down, it needs to be steady at the new higher or lower level. Think gas
            stove...more or less flame, but whatever setting you give it, it stays right
            there. This can also be done electrically, which is where you hear of
            burst-fire controllers (also called triac controllers) or variacs. Your triac
            clips part of the power going to your heater...you can adjust how much is
            clipped by adjusting a variable resistor. When you set it, it stays constant
            at the new power level. A variac is a variable transformer that lets you
            adjust the voltage to your heater...less voltage, less heat and vice versa.

            In a home rig, all you need to do is find the ideal heat input, set it and
            forget it. The remaining adjustments are based upon what your product is. A
            valve tweak here for a slower drip, a cooling adjustment there because your
            condensing water is warmer today than it was last week, and so forth.

            Trid
            -I'll try to explain PID control, and how it works and may or may not apply
            iffn's anybody is interested (in English, not engineer-ese).
          • Caleb Dunstan
            On the surface, this sounds good, even with keeping within 0.1 C tolerance. In ... But don¢t you need to keep the mash and the gradient of the drop in temp
            Message 5 of 23 , Mar 3, 2008
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              On the surface, this sounds good, even with keeping within 0.1 C tolerance. In

              > the case of coffee, hot water boilers, ovens, and the like, it's a really
              > precise, well controlled situation. For what we're doing, not so much.

               

              But don’t you need to keep the mash and the gradient of the drop in temp along the column fairly constant to get the best results?

               

              > Actually, the only flaw in how this operates is your solid state relay (SSR).
              > Not that it doesn't hold temperature well, but because it holds it by turning
              > the heat on and off (for people less familiar, a relay is just a switch that's
              > operated electrically instead of by hand). Even on such a small scale as
              > needed to maintain 0.1 degree stability, it's still a matter of on/off...just
              > more rapid.



              Yes, the SSR switches the current to the heating element on and off, but you can set it so it does this very fast - a couple of times a second.  This 'spikes' the element with current - but I don't think these spikes are reflected as the actual temperature fluctuation at the surface of the element - there is quite a lot of metal to heat up.

               

              > You're missing the point. You're wasting your time using head vapour
              > temperature as the trigger because you don't want it fluctuating AT
              > ALL in distillation. We're not simmering coffee here. Temperature
              > does NOT need to be controlled.

               

              I’m thinking mash temp controlling power input.  I don't quite follow what you're saying about head vapour temp - you don't want it fluctuating, but don't want to control it?  I don't quite follow.

               

              The composition of the vapour at the

              > head will automatically decide the temperature recordable there.

               

              Really?

               

              It

              > is POWER INPUT that needs to be controlled. This is done with a
              > burst-fire zero-switching controller. Slow on-off-on switches like
              > stove controllers will only cause surge boiling, as will your setup.
              > This destroys the two-way distilling action in the column.

               

              It's not slow.  Each cycle is like 250ms. I don't think it would cause surge boiling.

               

              Trid
              -I'll try to explain PID control, and how it works and may or may not apply
              iffn's anybody is interested (in English, not engineer-ese) .

               

              A PID is a smart little computer controller which looks at one or several input temperature probes (thermocouples) and it’s memory of what it’s done recently and controls how much heat you want to put out to bring something up to and keep at a set temperature. 


               

               

              ----- Original Message ----
              From: Trid <triddlywinks@...>
              To: Distillers@yahoogroups.com
              Sent: Tuesday, March 4, 2008 10:25:30 AM
              Subject: Re: [Distillers] Re:Temperature Controlers

              > --- In Distillers@yahoogro ups.com, Caleb Dunstan <phantompower@ ...>
              > > I'm a newbie, and have not actually built my still yet, but why not
              > just use a simple PID controller and a K-type thermocouple for
              > control, and hook that up to an SSR which is feeding your heating
              > element. That would give you the range and sensitivity, and most of
              > the PID's I've seen will give you control to about 0.1 of a deg C.
              > That's what we put on our espresso machine, and it works a treat.

              On the surface, this sounds good, even with keeping within 0.1 C tolerance. In
              the case of coffee, hot water boilers, ovens, and the like, it's a really
              precise, well controlled situation. For what we're doing, not so much.

              Actually, the only flaw in how this operates is your solid state relay (SSR).
              Not that it doesn't hold temperature well, but because it holds it by turning
              the heat on and off (for people less familiar, a relay is just a switch that's
              operated electrically instead of by hand). Even on such a small scale as
              needed to maintain 0.1 degree stability, it's still a matter of on/off...just
              more rapid.

              --- Harry <gnikomson2000@ yahoo.com> wrote:
              > You're missing the point. You're wasting your time using head vapour
              > temperature as the trigger because you don't want it fluctuating AT
              > ALL in distillation. We're not simmering coffee here. Temperature
              > does NOT need to be controlled. The composition of the vapour at the
              > head will automatically decide the temperature recordable there. It
              > is POWER INPUT that needs to be controlled.
              This is done with a
              > burst-fire zero-switching controller. Slow on-off-on switches like
              > stove controllers will only cause surge boiling, as will your setup.
              > This destroys the two-way distilling action in the column.

              Where this is a more frequently seen application, such as stovetops and such,
              this is still the principle that you're working against (not with) when
              utilizing either infinite switches (such as stovetops) or SSRs (PID controlled
              or not) or any other on/off switching device.

              Controlling a reflux rig is actually much simpler than something that would
              demand a PID controller, although one could make it complicated enough to apply
              it. You need a steady input of power, or heat. It needs to be variable in the
              sense that you can adjust the steady input up or down...but when it goes up or
              down, it needs to be steady at the new higher or lower level. Think gas
              stove...more or less flame, but whatever setting you give it, it stays right
              there. This can also be done electrically, which is where you hear of
              burst-fire controllers (also called triac controllers) or variacs. Your triac
              clips part of the power going to your heater...you can adjust how much is
              clipped by adjusting a variable resistor. When you set it, it stays constant
              at the new power level. A variac is a variable transformer that lets you
              adjust the voltage to your heater...less voltage, less heat and vice versa.

              In a home rig, all you need to do is find the ideal heat input, set it and
              forget it. The remaining adjustments are based upon what your product is. A
              valve tweak here for a slower drip, a cooling adjustment there because your
              condensing water is warmer today than it was last week, and so forth.

              Trid
              -I'll try to explain PID control, and how it works and may or may not apply
              iffn's anybody is interested (in English, not engineer-ese) .



              Never miss a thing. Make Yahoo your homepage.
            • abbababbaccc
              You need to keep the mash boiling in order to generate vapor that you can condense. The boiling point (i.e. temperature) increases as alcohol from the mash is
              Message 6 of 23 , Mar 3, 2008
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                You need to keep the mash boiling in order to generate vapor that you
                can condense. The boiling point (i.e. temperature) increases as
                alcohol from the mash is exhausted (see the boiling point curve Harry
                posted). It begins at around 88C and ends at 100C when all alcohol is
                gone. This is really more of a new_distillers stuff but just so you
                get it, YOU CAN NOT CONTROL MASH TEMPERATURE if you want to generate
                that vapor you need to condense in order to make distillate.

                Cheers, Riku

                --- In Distillers@yahoogroups.com, Caleb Dunstan <phantompower@...> wrote:
                >
                > On the surface, this sounds good, even with keeping within 0.1 C
                tolerance. In
                > > the case of coffee, hot water boilers, ovens, and the like, it's a
                really
                > > precise, well controlled situation. For what we're doing, not so much.
                >
                > But don¢t you need to keep the mash and the gradient of the drop in
                temp along the column fairly constant to get the best results?
                >
                >
              • Trid
                ... No. You have no control over the gradient, only the top end, the head. You have no control over what your boiler is doing because its composition
                Message 7 of 23 , Mar 3, 2008
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                  --- Caleb Dunstan <phantompower@...> wrote:
                  > But don¢t you need to keep the mash and the gradient of the drop in temp
                  > along the column fairly constant to get the best results?

                  No. You have no control over the gradient, only the top end, the head. You
                  have no control over what your boiler is doing because its composition controls
                  it, not you. When it's boiling, it's at the saturation temperature for the
                  combination of all liquids in it. As the concentration of ethanol is reduced,
                  the boiling temperature rises proportionately (but not linearly).

                  > Yes, the SSR switches the current to the heating element on and off, but you
                  > can set it so it does this very fast - a couple of times a second. This
                  > 'spikes' the element with current - but I don't think these spikes are
                  > reflected as the actual temperature fluctuation at the surface of the element
                  > - there is quite a lot of metal to heat up.

                  This is true...there is a lot of metal to heat up. Carry that one step further
                  to the scale of a still versus a coffee or cappuccino machine. There's a lot
                  more liquid to heat up as well (considering your boiler will be quite a bit
                  larger in volume than a coffee machine). As such, you'll suffer greater
                  temperature swings due to this. Remember also, your heating elements will draw
                  much more power in the boiler. SSRs or even mechanical relays will wear out
                  much quicker under this higher load...unless you're prepared to drop a lot of
                  money on some industrial grade relays that are rated to switch that much
                  current that frequently for that long on a regular basis.

                  > I¢m thinking mash temp controlling power input. I don't quite follow what
                  > you're saying about head vapour temp - you don't want it fluctuating, but
                  > don't want to control it? I don't quite follow.

                  Mash temp is not relevant to power input. The rate at which it boils is a
                  result of the power input (and thus vapor speed) but not temperature. The
                  temperature will always be at the saturation temperature of the liquids in the
                  mash. Any lower and you're no longer boiling...just hot.

                  > The composition of the vapour at the
                  > > head will automatically decide the temperature recordable there.
                  >
                  > Really?

                  Really.
                  The vapor temperature will be at the saturation temperature of whatever
                  combination of ethanol and water is present. If you have poor reflux, and your
                  ethanol portion is less than 96.5% of the vapor, then the temperature will show
                  this...it will be higher. More reflux will reduce your head temperature and
                  the product will show this by being higher % of ethanol.

                  > It
                  > > is POWER INPUT that needs to be controlled. This is done with a
                  > > burst-fire zero-switching controller. Slow on-off-on switches like
                  > > stove controllers will only cause surge boiling, as will your setup.
                  > > This destroys the two-way distilling action in the column.
                  >
                  > It's not slow. Each cycle is like 250ms. I don't think it would cause surge
                  > boiling.

                  On the scale you're presently working with, perhaps not, but you're also not
                  controlling boiling rate, you're controlling temperature. In the context of a
                  still, it needs to be boiling...otherwise, you're not going to get an
                  appreciable takeoff rate and you'll be waiting forever for the lower boiling
                  point volatiles (the nasty, solvent odors you're catching) to evaporate.

                  The bottom line is that one doesn't control the boiler temperature. The heat
                  input is adjusted to tweak the boiling rate and therefore the vapor speed.
                  Them's just the physics of it. Don't think you're the first to think of
                  controlling the boiler temperature to get JUST ethanol...nor was I when I
                  considered it back when I was starting out.

                  > -I'll try to explain PID control, and how it works and may or may not apply
                  > iffn's anybody is interested (in English, not engineer-ese) .
                  >
                  > A PID is a smart little computer controller which looks at one or several
                  > input temperature probes (thermocouples) and it¢s memory of what it¢s done
                  > recently and controls how much heat you want to put out to bring something up
                  > to and keep at a set temperature.

                  That's the condensed version...and you're dead on regarding temperature. I'm
                  talking about HOW it accomplishes it.
                  PID is the means by which the smart little controller works, not what it is.
                  It stands for "Proportional Integral Derivative." It compares an input (or
                  multiple like you mentioned) which is the PV (process variable). This is what
                  you have. Then there's the setpoint, what you want. It compares what you have
                  to what you want. The difference is called the "error." The "proportional"
                  component of your PID is a span...it's the magnitude of your error which will
                  cause it produce the full output of your control variable (CV). This would be
                  your SSR being on constantly, or a valve to be turned completely on (or off)
                  depending on what the desired position is. Next is the Integral (or sometimes
                  referred to as "integration"). This is a repetitive reevaluation of the error.
                  It's like the little kid in the back seat saying "are we there yet?" If after
                  a period of time (seconds, minutes, milliseconds...whatever is programmed)
                  there is still an error, the integration adds some to the output of the
                  calculation. The smaller the error, the less it adds, and vice versa. The
                  Derivative function further fine tunes this response to ensure the PV is
                  exactly on its setpoint at all costs...this translates to rapidly changing the
                  CV in order to react to the slightest variance. Derivative is actually very
                  rarely used because its rapid and constant readjustment leads to premature
                  failure of equipment and components due to fatigue.

                  Now, in the context of the SSRs that maintain temperature, the output of the
                  PID calculation then has to translate into pulses of on/off. It can be done
                  with either a predetermined value and just pulse that amount more or less
                  frequently (the output of the PID then being the frequency of the pulses) or it
                  can be adaptive where it records the rate at which the PV changes when the CV
                  is on (or off) and thus decides the length of time the CV is on in order to
                  affect that magnitude of change.

                  That being said (and I think I may have failed a bit in the English-ness of
                  it), because we're not in need of controlling heat input for the sake of
                  temperature control, that becomes irrelevant for the boiler heaters. Where it
                  becomes potentially useful is in controlling your reflux rate. The process
                  variable would be your head temperature, the control variable would be your
                  takeoff valve, and your setpoint would be that of the ethanol/water azeotrope
                  (I can never remember that exact number because it's never be relevant to
                  me...I happily pot still). However, this has already been covered by ARC
                  (automatic reflux control) which is a mechanical means of controlling your
                  reflux ratio based on the head temperature. Not quite as dead-nuts accurate as
                  PID, but plenty adequate for our little hobby.

                  Don't get me wrong, I'm not at all trying to discourage tinkering and tweaking
                  on one's rig...this *is* a hobby, after all, and we're free to futz about with
                  the mechanics of our rigs in the name of fun. But just as a back yard mechanic
                  wouldn't try to install nitrous in is his cooling system, it's about the
                  context and knowing what portion needs control, why, and how...and what
                  doesn't.

                  Trid
                  -way too late to "make a long story short"
                • Trid
                  ... ...or you could say it that way. Geez, I need to work on my brevity. Trid -pedantic tonight
                  Message 8 of 23 , Mar 3, 2008
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                    --- abbababbaccc <abbababbaccc@...> wrote:

                    > You need to keep the mash boiling in order to generate vapor that you
                    > can condense. The boiling point (i.e. temperature) increases as
                    > alcohol from the mash is exhausted (see the boiling point curve Harry
                    > posted). It begins at around 88C and ends at 100C when all alcohol is
                    > gone. This is really more of a new_distillers stuff but just so you
                    > get it, YOU CAN NOT CONTROL MASH TEMPERATURE if you want to generate
                    > that vapor you need to condense in order to make distillate.

                    ...or you could say it that way.

                    Geez, I need to work on my brevity.

                    Trid
                    -pedantic tonight
                  • Harry
                    ... Nothing wrong with the way you said it, Trid. Or you Riku. With all the variables, the complex processes and actions/reactions going on in distillation,
                    Message 9 of 23 , Mar 3, 2008
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                      --- In Distillers@yahoogroups.com, Trid <triddlywinks@...> wrote:
                      > ...or you could say it that way.
                      >
                      > Geez, I need to work on my brevity.
                      >
                      > Trid
                      > -pedantic tonight
                      >


                      Nothing wrong with the way you said it, Trid. Or you Riku. With all
                      the variables, the complex processes and actions/reactions going on
                      in distillation, I'm constantly amazed that we manage to explain it
                      at all!

                      Some things can be related in a few words, some things require
                      detailed dissection before the light goes on. Where would we be
                      without the ability to communicate?
                      (I shudder at the thought of the struggle my nearly illiterate text-
                      shorthand-messaging kids will have in the future, trying to get their
                      heads around things).


                      Slainte!
                      regards Harry
                      http://distillers.tastylime.net/library/
                    • whynda
                      ... YOU CAN NOT CONTROL MASH TEMPERATURE if you want to generate ... but nothing works either :(
                      Message 10 of 23 , Mar 3, 2008
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                        --- In Distillers@yahoogroups.com, "abbababbaccc" <abbababbaccc@...>
                        wrote:
                        >
                        >Snip >>>>
                        YOU CAN NOT CONTROL MASH TEMPERATURE if you want to generate
                        > that vapor you need to condense in order to make distillate.
                        >
                        > Cheers, Riku
                        >


                        >Ummmm .... I control my MASH TEMPERATURE, says he smerquing.

                        but nothing works either :(
                      • abbababbaccc
                        ... To what purpose, what do you achieve with that? If you want vapor you need to boil the mash and boiling temperature depends on mash composition which
                        Message 11 of 23 , Mar 3, 2008
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                          --- In Distillers@yahoogroups.com, "whynda" <hstuiber@...> wrote:
                          >
                          > >
                          >
                          > >Ummmm .... I control my MASH TEMPERATURE, says he smerquing.
                          >
                          > but nothing works either :(
                          >

                          To what purpose, what do you achieve with that? If you want vapor you
                          need to boil the mash and boiling temperature depends on mash
                          composition which changes over time.

                          Of course if you mean mash temperature during fermentation that's
                          another thing but we were talking about distillation here.

                          Cheers, Riku
                        • whynda
                          ... you ... Sorry Riku, It was an attempt at sad humour directed at the people that will insist on trying to control mash temperature. Harry (the other one)
                          Message 12 of 23 , Mar 4, 2008
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                            --- In Distillers@yahoogroups.com, "abbababbaccc" <abbababbaccc@...>
                            wrote:
                            >
                            > --- In Distillers@yahoogroups.com, "whynda" <hstuiber@> wrote:
                            > >
                            > > >
                            > >
                            > > >Ummmm .... I control my MASH TEMPERATURE, says he smerquing.
                            > >
                            > > but nothing works either :(
                            > >
                            >
                            > To what purpose, what do you achieve with that? If you want vapor
                            you
                            > need to boil the mash and boiling temperature depends on mash
                            > composition which changes over time.
                            >
                            > Of course if you mean mash temperature during fermentation that's
                            > another thing but we were talking about distillation here.
                            >
                            > Cheers, Riku



                            Sorry Riku, It was an attempt at sad humour directed at the people
                            that will insist on trying to control mash temperature.

                            Harry (the other one)
                            >
                          • ArnieW
                            I was thinking an analogy might help here. If you are set for a romantic night and want to dim the light in your lounge room, then you adjust the light-dimmer
                            Message 13 of 23 , Mar 4, 2008
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                              I was thinking an analogy might help here.

                              If you are set for a romantic night and want to dim the light in your
                              lounge room, then you adjust the light-dimmer control to set the
                              ambient light. At this point all that is important is setting the
                              right amount of light to give the desired effect. The temperature of
                              the light globe is irrelevant - the only important thing is the
                              lighting effect. The temperature of the globe will be higher if it is
                              a hot night. The temperature of the globe will be lower if it is
                              mid-winter and there is a cold breeze coming in through the window.
                              But this does not matter as long as the light level is right.

                              When distilling, the power in the boiler is all that matters because
                              this determines how much vapour will evaporate. The temperature of the
                              vapour in the head is not determined by the power in the boiler. It
                              will be higher if reflux is poor, lower if in full reflux. Increasing
                              the power will choke the column because of excessive vapour.

                              I use PID control to regulate mash temperatures in my brewing system -
                              and there it is great. The boiler requirements for distilling are so
                              simple that a single heating element of the right power (say 1000W)
                              will be near enough to be perfect without any fancy power control at all.

                              cheers all
                            • morganfield1
                              Last I knew, Bob the Borg was the Keeper of the Secret Knowledge of controlling the boiling point temperature! I wonder how he s doing, anyway. Tip one,
                              Message 14 of 23 , Mar 4, 2008
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                                Last I knew, Bob the Borg was the "Keeper of the Secret Knowledge" of
                                controlling the boiling point temperature! I wonder how he's doing,
                                anyway.

                                Tip one, Morgan

                                > >
                                >
                                >
                                > >Ummmm .... I control my MASH TEMPERATURE, says he smerquing.
                                >
                                > but nothing works either :(
                                >
                              • mstehelin
                                I have been looking for low power elements but have not found any. All the elements that I pull out of the kettles (that I pull out of the dumpster/recycling)
                                Message 15 of 23 , Mar 4, 2008
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                                  I have been looking for low power elements but have not found any. All
                                  the elements that I pull out of the kettles (that I pull out of the
                                  dumpster/recycling) are 1500W. Any suggestions on where to source
                                  1000 W or lower would be appreciated
                                  Cheers
                                  M


                                  --- In Distillers@yahoogroups.com, "ArnieW" <arniew@...> wrote:
                                  >
                                  > I was thinking an analogy might help here.
                                  >
                                  > If you are set for a romantic night and want to dim the light in your
                                  > lounge room, then you adjust the light-dimmer control to set the
                                  > ambient light. At this point all that is important is setting the
                                  > right amount of light to give the desired effect. The temperature of
                                  > the light globe is irrelevant - the only important thing is the
                                  > lighting effect. The temperature of the globe will be higher if it is
                                  > a hot night. The temperature of the globe will be lower if it is
                                  > mid-winter and there is a cold breeze coming in through the window.
                                  > But this does not matter as long as the light level is right.
                                  >
                                  > When distilling, the power in the boiler is all that matters because
                                  > this determines how much vapour will evaporate. The temperature of the
                                  > vapour in the head is not determined by the power in the boiler. It
                                  > will be higher if reflux is poor, lower if in full reflux. Increasing
                                  > the power will choke the column because of excessive vapour.
                                  >
                                  > I use PID control to regulate mash temperatures in my brewing system -
                                  > and there it is great. The boiler requirements for distilling are so
                                  > simple that a single heating element of the right power (say 1000W)
                                  > will be near enough to be perfect without any fancy power control at
                                  all.
                                  >
                                  > cheers all
                                  >
                                • martin martins
                                  Mobile kettles, the type that are designed for heating a couple of cups of water in hotel rooms. If hotel kettles go missing I am not liable. Oh, they run off
                                  Message 16 of 23 , Mar 4, 2008
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                                    Mobile kettles, the type that are designed for heating a couple of cups of water in hotel rooms.

                                    If hotel kettles go missing I am not liable. Oh, they run off the mains as well :) Try your pound store.

                                    ----- Original Message ----
                                    From: mstehelin <mstehelin@...>
                                    To: Distillers@yahoogroups.com
                                    Sent: Tuesday, March 4, 2008 10:53:16 PM
                                    Subject: [Distillers] Re:Temperature Controlers

                                    I have been looking for low power elements but have not found any. All
                                    the elements that I pull out of the kettles (that I pull out of the
                                    dumpster/recycling) are 1500W. Any suggestions on where to source
                                    1000 W or lower would be appreciated
                                    Cheers
                                    M




                                    Never miss a thing. Make Yahoo your homepage.
                                  • Trid
                                    ... Failing that, you can always find one that s rated for 240V and for 4 times the power that you need. Then just put 120V on it instead and you have exactly
                                    Message 17 of 23 , Mar 4, 2008
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                                      --- mstehelin <mstehelin@...> wrote:

                                      > I have been looking for low power elements but have not found any. All
                                      > the elements that I pull out of the kettles (that I pull out of the
                                      > dumpster/recycling) are 1500W. Any suggestions on where to source
                                      > 1000 W or lower would be appreciated
                                      > Cheers
                                      > M

                                      Failing that, you can always find one that's rated for 240V and for 4 times the
                                      power that you need. Then just put 120V on it instead and you have exactly the
                                      power you were seeking.

                                      For example, if you want a 600W heater, find a 240V 2400W heating element and
                                      just apply 120V instead. Since Power = Voltage ^2 / Resistance and your
                                      resistance stays the same... if you cut the voltage in half, your power is
                                      (1/2)^2 or 1/4 the original value.

                                      Then again, I don't remember if you are in the US or not and even have this
                                      option.

                                      Trid
                                      -but the theory still holds :)
                                    • mstehelin
                                      I think that your average North American hot water tank heater would fit those requirements. Great! Now I can put Riku s spiral still to the test! Cheers M
                                      Message 18 of 23 , Mar 4, 2008
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                                        I think that your average North American hot water tank heater would
                                        fit those requirements. Great! Now I can put Riku's spiral still to
                                        the test!
                                        Cheers
                                        M


                                        --- In Distillers@yahoogroups.com, Trid <triddlywinks@...> wrote:
                                        >
                                        > --- mstehelin <mstehelin@...> wrote:
                                        >
                                        > > I have been looking for low power elements but have not found any. All
                                        > > the elements that I pull out of the kettles (that I pull out of the
                                        > > dumpster/recycling) are 1500W. Any suggestions on where to source
                                        > > 1000 W or lower would be appreciated
                                        > > Cheers
                                        > > M
                                        >
                                        > Failing that, you can always find one that's rated for 240V and for
                                        4 times the
                                        > power that you need. Then just put 120V on it instead and you have
                                        exactly the
                                        > power you were seeking.
                                        >
                                        > For example, if you want a 600W heater, find a 240V 2400W heating
                                        element and
                                        > just apply 120V instead. Since Power = Voltage ^2 / Resistance and your
                                        > resistance stays the same... if you cut the voltage in half, your
                                        power is
                                        > (1/2)^2 or 1/4 the original value.
                                        >
                                        > Then again, I don't remember if you are in the US or not and even
                                        have this
                                        > option.
                                        >
                                        > Trid
                                        > -but the theory still holds :)
                                        >
                                      • mavnkaf
                                        Hi mstehelin, I found this on the net for $50 AUD, I m not sure what a sink heat is but it might be ok? product No.90704 750w 1 BSP Sink Heater
                                        Message 19 of 23 , Mar 4, 2008
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                                          Hi mstehelin, I found this on the net for $50 AUD, I'm not sure what
                                          a sink heat is but it might be ok?

                                          product No.90704 750w 1'' BSP Sink Heater

                                          http://tinyurl.com/yslbrv

                                          Cheers
                                          Marc



                                          --- In Distillers@yahoogroups.com, "mstehelin" <mstehelin@...> wrote:
                                          >
                                          > I have been looking for low power elements but have not found any.
                                          All
                                          > the elements that I pull out of the kettles (that I pull out of the
                                          > dumpster/recycling) are 1500W. Any suggestions on where to source
                                          > 1000 W or lower would be appreciated
                                          > Cheers
                                          > M
                                          >
                                        • Robert Hubble
                                          Trid, you said it just fine. That from an old broken-down retired EE who use to write theory-of-operations crap about embedded systems for a living. It s been
                                          Message 20 of 23 , Mar 4, 2008
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                                            Trid, you said it just fine. That from an old broken-down retired EE who use to write theory-of-operations crap about embedded systems for a living.
                                             
                                            It's been a long time since I took a control-circuit class, but I don't think we ever studied anything as sophisticated as what you describe, even with discrete components. That differentiation on the end sounds really clever. I guess I'm going to have to go to Digi-key and look up PIDs.
                                             
                                            For all the kibbitzing and tutorials I've done for designing embedded syatems, I've never actually started one from scratch, and a buddy of mine sent me a USB-dongle that's a development system for TI's MSP430 controller. We had talked about my need for several thermometer readouts for my new (possible water-bath) still. I found a single-wire bus digital thermometer, so you can string them all on one wire like Christmas-tree bulbs, kinda, but they have to be polled by a processor, and the 430 looks like the cheapest, easiest to develop thing I've seen.
                                             
                                            I'm an awful procrastinator, but I'm planning on building this sucker anyway, and maybe dump all the temps to a logfile on a PC, as well as a bank of LED displays. That would be cool.
                                             
                                            Anyway, thanks for the great explanation, and screw brevity.
                                             
                                            Man, I like this group.

                                            Zymurgy Bob, a simple potstiller



                                            To: Distillers@yahoogroups.com
                                            From: triddlywinks@...
                                            Date: Mon, 3 Mar 2008 22:21:49 -0800
                                            Subject: Re: [Distillers] Re:Temperature Controlers

                                            --- abbababbaccc <abbababbaccc@ yahoo.com> wrote:

                                            > You need to keep the mash boiling in order to generate vapor that you
                                            > can condense. The boiling point (i.e. temperature) increases as
                                            > alcohol from the mash is exhausted (see the boiling point curve Harry
                                            > posted). It begins at around 88C and ends at 100C when all alcohol is
                                            > gone. This is really more of a new_distillers stuff but just so you
                                            > get it, YOU CAN NOT CONTROL MASH TEMPERATURE if you want to generate
                                            > that vapor you need to condense in order to make distillate.

                                            ...or you could say it that way.

                                            Geez, I need to work on my brevity.

                                            Trid
                                            -pedantic tonight



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