Jump to content
ADI Forums

meerkat

Members
  • Content Count

    143
  • Joined

  • Last visited

  • Days Won

    4

meerkat last won the day on September 18

meerkat had the most liked content!

Community Reputation

15 Neutral

About meerkat

  • Rank
    Active Contributor

Contact Methods

  • Website URL
    http://www.katmarsoftware.com/alcodens.htm

Profile Information

  • Gender
    Male
  • Location
    South Africa

Recent Profile Visitors

2,957 profile views
  1. I haven't done it this way, but that is not to say you can't make it work. It seems unnecessarily complicated and I always prefer the KISS approach. Hopefully you will get a comment from someone who has tried it.
  2. The problem is not that the return line discharges above the level in the pot. The problem is that there is nothing to stop the vapors flowing up the return line. If the discharge is above the liquid level then there must be an external liquid seal in the return line to block the vapors. There are pro's and con's for internal and external liquid seals, but both can work perfectly well. A similar situation exists with the downcomer on a bubble cap tray. If the lower end of the downcomer does not have a liquid seal - either with an inverted cap or by extending the downcomer to below the liquid level on the tray below, then the vapor will flow up the downcomer rather than through the bubble caps.
  3. It is very important that vapor be prevented from going up the return line. As you said, the vapor will "fight" with the liquid because they are going in different directions. The way to stop the vapor going back up the return line is to install a liquid seal. This seal can either be inside the pot (by having the return line extend to below the liquid surface) or external to the pot by installing a U or P, but not an S, trap. I have seen vapor locking occur with an internal seal, ie one that enters the pot above the liquid level but extends down below the surface. This is because it is quite tricky to get the sizing of the line just right to be able to flush any incondensible gases down the seal leg. However, this is easily fixed by drilling a small hole (approx 1/8") in the elbow inside the pot above the liquid level. This is big enough to allow the small quantity of trapped gases to escape into the pot, but small enough to limit vapors from the pot entering the return line and causing problems.
  4. meerkat

    steady take off rate

    You can verify this during the next run by holding a sheet of paper over your burp tube to see if a vacuum is being developed at any stage.
  5. meerkat

    steady take off rate

    @Southernhighlander I have no doubt that you can build a complete bain marie-based system. The problem in this situation could be mismatched components. Is the column being used the same diameter that you would install on this boiler? Are the plates the same design? Are the power and positioning of the agitator as per your design? Is the heating power what you would use? @adamOVD It would be useful if you could find some other parameter that is cycling at the same frequency as the product flow, as this could indicate the cause. For example, can you measure the amps to the agitator? If the agitator is causing a vortex the entrained vapor might be interfering with the heat transfer from the shell and causing the cycling. Does the temperature in the jacket vary? Can you measure the pressure in the boiler? Does it cycle? I am pulling things out of the air here, but you need to measure whatever you can and try to find something that is cycling in sync with the production rate.
  6. meerkat

    steady take off rate

    @Southernhighlander and @adamOVD - I agree 100% on the need for the "burp tube". I always install them, although I always include a 3 or 4 ft vertical riser from the elbow. But even with the riser I have seen liquid gushing from the vent. The venting of uncondensible gases is critical and I have seen operators on continuous plants using the smell from these vents as an indication of the operation of the column. I would be very careful about blanking it off. PeteB's concern about sucking air into the condenser is valid, but I have found this to only happen when the condenser is significantly oversized or the water is unusually cold. In my experience this cycling of the product rate is caused by either bad piping design around the condenser, or by cycling of the heat input in the boiler. I suppose it could be caused by the plates but I have never seen that and it seems to be happening here whether the plates are installed or not. Most of the cycling cases I have come across have been caused by condenser piping design and that was the motivation for my questions. @vsaks had exactly this problem last year. But from the photo you have supplied and the answers to the questions I think in this case the problem is not around the condenser. Unfortunately most of my experience on the heating side has been with thermosiphon reboilers and I have never used a bain marie boiler. Cycling can definitely occur with an oversized thermosiphon reboiler so in view of the elimination of the condenser piping and the plates as suspected causes I would concentrate on the heating side.
  7. meerkat

    steady take off rate

    Below the tapered section at the bottom of the condenser there is a tee with a 90 degree elbow on it. Is this a vent that is always open? If it is a vent and the surging is significant I would expect liquid to come out here during the surges - or is the flow during the surges not that much more than during the slow times? Any feel for the ratio between the maximum and minimum flows? Are the surges enough to cause the parrot to overflow? Does the flow out of the parrot ever stop completely during the slow part of the cycle? Do you see bubbles coming to the surface of the parrot during the surges?
  8. meerkat

    TTB stopped our production due to high proof

    @Patio29Dadio - I agree with you. I have assumed that these density variations are "worst case" examples and that they therefore give the largest error possible in the proof reading. I only wanted to give a better feel for what these accuracies meant. The real interpretation of the accuracy is a bit more complicated. For example, Anton Paar give the accuracy of the 1001 as 0.0001 g/cm3 and the repeatability as 0.00005 g/cm3 (expressed as a standard deviation). This means that if you ran the same sample 1000 times then 680 of the readings would be within 0.00005 g/cm3 (1 std deviation) of some average density and 997 would be within 0.0001 g/cm3 (two std deviations) of that average. I suspect that the difference between this average and the true density is what they call the accuracy. If someone from Anton Paar is reading this it would be great to have your input. Very few labs interpret their results as rigorously as this.
  9. meerkat

    TTB stopped our production due to high proof

    These allowable errors do sound very small, but I find that to appreciate what they really mean it helps to turn the density variations into proof variations. The effect of a density change on the apparent proof depends on what the actual proof is, so to keep it realistic I will take an 80 proof product as the example (tax-wise this is probably where the TTB is most interested!) From TTB Table 6 we can get the SG in vacuum and this is very close to the density in g/cm3. For 80 proof this is 0.95178. If we add the density variations given by Patio29Dadio above to this value we can see what impact the density has on the apparent proof DMA 501 density error 0.001 SG = 0.95178 + 0.001 = 0.95278 and proof = 78.71 DMA 1001 density error 0.0001 SG = 0.95178 + 0.0001 = 0.95188 and proof = 79.88 DMA 4500 density error 0.00001 SG = 0.98178 + 0.00001 = 0.95179 and proof = 79.99 Based on this it looks to me as though the DMA 501 is not good enough for commercial proofing, the DMA 1001 is probably similar to what most distillers will achieve with a good hydrometer and with the DMA 4500 if you are shooting for the man in the moon you will hit him right on the nose.
  10. meerkat

    Cane sugar

    The convention for expressing concentrations in mass per volume terms is to use the mass of the solute (in this case, sugar) and the volume of the solution. The solution is the mixture of the solute (sugar) and the solvent (water or spirit). That is why I stated the concentration as "855 gram per liter of syrup". Note that a concentration given in mass/vol terms must always include a reference temperature because the volume changes with temperature, although of course the mass does not. I have seen data where the concentration is expressed as grams of solute per liter of solvent, but this is rare and would always be specifically stated as such because of the general acceptance of the convention described above. So, to make up a syrup of 400 gram per liter at 20°C you would put 400 grams of sugar in a 1 liter container and then add water until the combined volume reaches 1 liter, all the while carefully maintaining the temperature at 20°C. An easier and more accurate way to get to 400 gram per liter at 20°C would be to use a conversion table (or even better, AlcoDens LQ😉) to determine that this concentration is equivalent to 34.8 mass % and simply weigh out the 749.4 grams (= (400 / 34.8) x 65.2) of water and add it to the 400 grams of sugar. In this way you do not have to worry about the temperature.
  11. meerkat

    Heads and tails when using NGS

    @Roger , I'm sure you were just trying to have a bit of fun but you need to see your comments from the perspective of the person who is asking the question. If a person who has openly labelled themself as a newbie gets a very specific reply from a member with a high reputational ranking, such as yourself, then the OP is going to take that reply seriously and will not see it as the facetious comment it is intended to be. The OP may not have been following the "GNS Cost and Availability" thread and would not necessarily see your reply in that context. Also, for someone in the future reading this thread it will mislead and confuse them. To anybody else who is confused by Roger's and my comments, please read the "GNS Cost and Availability" thread for context.
  12. meerkat

    Cane sugar

    Yes, the solubility of sucrose decreases as the alcohol content increases. At 20°C the saturation solubility of sucrose in pure water is about 65 mass% or 855 gram per liter of syrup. If you are making a 100 proof liqueur the solubility limit of sucrose drops to 28 mass% or 285 gram/liter. In the cold winter temperatures of Canada the solubility will be a bit less. I don't have the experience to say whether crystallization will occur in the neck or base of the bottle, but I suppose either would be unacceptable.
  13. meerkat

    Cane sugar

    Jen, unless you have very high sugar loading or very high proof, there should not be a problem with crystallization. Invert sugar is more soluble than sucrose, so that would help if you are aiming for very sweet products. When making up a 1:1 (or any other ratio, for that matter) sucrose syrup it is important to measure the parts by weight rather than by volume. It is very hard to get consistent quantities of granular sugar when measuring volumetrically because the bulk density will vary from bag to bag and from batch to batch. If you want consistent taste and proofing it helps enormously to have consistent quality syrup.
  14. I have added Column L to your spreadsheet and attached it here. A value that has an equal number of occurrences above and below it is called the median (the midpoint of the frequency distribution in stats-speak). Cell L2 initially contained my guess for the median. I have set the values in Column L to be +1 if the actual net fill value in Column H is more than my guessed value for the median, or to -1 if the actual value is less than the guessed median. The total of all the + and - ones in Column L should be zero if there are an equal number of aboves and belows. Excel's Goal Seek function makes it easy to find the actual median using its internal trial and error functions. The median turns out to be 701.6. It is useful to compare this with the mean (the usual understanding of "average") which I have shown in Cell H27. The fact that the mean (701.7) is so close to the median (701.6) is an indication that your data points are normally distributed (i.e. follow the typical bell curve) and this is a "good thing" (tm). Because the median is 4.6 grams lower than your target fill of 706.2 and the median and mean are so similar, I suspect that if you simply increase the target to 710.8 (=706.2+4.6) then you will get a mean value very close to 706.2 and your overs and unders will be roughly equal. 898089352_ExpressfillFillerAudit - mod by HCW.xlsx
  15. meerkat

    Checking Fill Level (27 CFR 19.356)

    @indyspirits, Yes there is. The icon with the ruler next to the beaker calls up the Volume Correction Calculator (which also converts between mass and volume). The calculation below shows that 750 ml at 60°F becomes 756.4 ml at 80°F. Note that the mass remains 706.1 grams and this is why almost everyone prefers to bottle by mass.
×