StillDragon® Community Forum

Welcome!

Be part of our community & join our international next generation forum now!

In this Discussion

Temperature Sensor Locations?

Hello All,

I am about to buy a Dash2, but I am trying to get all the extras I may need accounted for.
Long time all grain HomeBrewer started that Hobby in 1999 and have large shop building devoted to brewing.
I love Arduinos and have built many projects with them including Open Sprinkler and BrewPi.

I have built a power output controller for my boiler with an Arduino and some SSR, but I also got a nice big 128x64 LCD to show me power output and temp sensor info.

So after all that here is the question: How many temp sensors would you have on your rig?

I plan on using these DS18B20 Digital temperature sensor
I use these on my BrewPI

They are very accurate (12bit) and only use one input and can be daisy chained 100 deep if you wanted.

So if you could have as many temp sensors as you want and a snazzy screen showing them all, how many and where would you have them?

I was thinking : the boiler , just above the dephlegmator, just below the shotgun and output side of the condensers water fitting?

Thank you for the advice, I don't know what I am doing but insist on building this stuff now even though I am sure it will change as I grow.

«134

Comments

  • Well I am still building mine but if you are asking for a wish list here goes.

    1 in the boiler liquid for power management during warm up - especially if you distill on solids.

    1 in the boiler headspace if you use vapour temperature to start your coolant pump.

    1 in each chamber - either in vapour or liquid - personal choice.

    1 to monitor the product vapour temperature above the dephlegmator. Used to monitor quality and also to switch off the coolant pump.

    1 to monitor the coolant temperature inside the dephlegmator or on the coolant output line for convenience.

    1 on either the product condenser coolant output or inside the parrot, to monitor product temperature.

    1 in the boiler headspace if you use vapour temperature to switch off the power to the boiler at the end of the run. Especially with double boilers if you are completing the run on stored residual heat in a thermal transfer fluid like glycol.

  • Sure, put them everywhere that you can imagine to monitor the still and record everything.

    But...

    Put ONE in the dephegmator to control the still. Call it A
    Put ONE in the parrot to control the product temperature. Call it B
    C can be the vapor temp between the two.

    A is more important than B by a magnitude. C is just information that the parrot already reads.

    All else is fluff.

    I have lots of fluff. Only A is critical.

    But I love info so I have more fluff than necessary. If you are a control freak, like I am, then by all means put sensors everywhere. Just my 2 cents on what is priority and necessary.

  • @Lloyd so you are saying "in the deflag" as in water temp around the pipes type of thing, rather than the traditional vapour temp to use semi auto control? I thought most of the recent discussions on builds/panels was geared towards vapor temps either just above the deflag or even just below ? Have I missed a few posts lately perhaps ?, I know I've not been around for a while, been sidetracked.

    @DemBones welcome, and I'd be keen to see how you go with the projects. We love pics and vids, wiring and hints are also handy.

    I'm still using the "el-cheapo" temp meters, main one I watch is above deflag.

    Fadge

  • I would love to see the dephlegmator shipped with another 1/2 or 3/8 npt fitting in the middle to accept a short RTD probe with direct contact. Omega and others make stubby stainless RTDs that would be absolutely perfect, no thermowell needed.

  • I think the middle would not be good... if one or two people in the US wanted such a thing to experiment with and report back to the community, I would be happy to weld one or two for free if you shipped it to me and paid shipping both ways, but I think you will find that measuring on the outlet is better in all situations where there is the slightest coolant flow... I personally think that vapor temp above the dephleg may be even better, ans that is wht you actually are trying to control... (no one says "I make great neutral by having water come out at 45C", but it is feasible to say that you keep it at azeotrope, and that is direct reflection of the vapor above the dephleg... and monitoring output temp of the dephleg is useful to see how 'used' your cooling water is and if you can cut back if there is no vapor above the dephleg... think of the vapor first starting to go through the dephleg, some of it will cool on the walls of the tube and heat the metal tubes and then the water, but some made it through, and that will show on the temperature probe above the dephleg way quicker than one immersed in water surrounding the tube..

  • You could just screw a tee into the outlet of the reflux condensor (i hate the dephlag word) before the QC.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • if you weld the thermowell fitting to the existing 3/8" FPT fitting on the Reflux Condenser, I think you get the most accurate temp, and the quickest reaction time. I use something like this, but machine down the weld part to be narrower to fit closer to the body of the RC.

    Stainless Instrumentation Butt Weld Connector 1/4" ref Swagelok SS-400-1-4W @ eBay

    Here one is on the Product Condenser:

    image

  • I guess I don't understand why you would want to use the water as the means of controlling the product you are taking off. This could change from one run to the next depending on the temp of the water and flow. Wouldn't you always be playing with your setpoint? Vapor temp tells us what is being pulled so why wouldn't you just monitor that? Maybe I am missing something?

  • I agree with you @Wallybox , and agree 100%, but a lot of people seem to dial in the system each time so that does not matter.. I dial my system in by vapor temp, and use the water outlet temp on the RC to judge water conservation.

    FYI - here is the fitting I used, I machined the threads off, but in a pinch, you could drill and tap the 1/8" NPT hole and use this as is....

    Tylok SS-4-DMC-2 ,1/4 tube x 1/8 NPT swagelok cross ref.SS-400-1-2 ,several @ eBay

  • edited May 2014

    Great Responses Guys! thanks I am going to get some pizza and a beer and digest your replies and my dinner :-?

  • @Wallybox said: I guess I don't understand why you would want to use the water as the means of controlling the product you are taking off. This could change from one run to the next depending on the temp of the water and flow. Wouldn't you always be playing with your setpoint? Vapor temp tells us what is being pulled so why wouldn't you just monitor that? Maybe I am missing something?

    There is a direct relationship between the discharge water temp of the dephleg and the head (vapor) temp with regard to optimal performance/collection speed/desired purity.

    Even though reservoir water temps may rise through the course of a run...it is still possible to maintain an optimal discharge water temp at the dephlegmator (depending on some other variables ).

    Even with fluctuating /seasonal fresh water temps it is no problem to control discharge water temps by governing the flow rate of the water.

    All data is useful.

    StillDragon North America - Your StillDragon® Distributor for North America

  • Agreed, all data is useful and is why I have so many sensors sprinkled over my still.
    My earlier remark about the sensor being in the dephleg is still experimental, at least for me. I was controlling the water input valve via the PID controller using the vapor temp as the control. Olddog suggested to change that so that the sensor leading to the PID was actually in the water inside the dephlem instead. It added stability and the vapor temp remained rock solid instead of having little swings up and down.

  • Bear in mind as well that to increase the sensitivity and degree of control of the dephlegmator, many folks supply it with warm water. If you supply it with cold water there is a risk that you can over cool the reflux condensate. This is just a waste of energy and it upsets the stability of the column by excessively cooling the top plate.

    For this reason some folks monitor the dephlegmator temperature to ensure it is not TOO cold.

  • edited May 2014

    Thanks for the replies.
    So as it stands does the Dash 2 have places to add temp probes ?

    Here is what I was thinking for probes. Using the Stainless Instrumentation Butt Weld Connector 1/4" as linked by @CothermanDistilling.

    And then use these Thermowell 6mm x 1.96'', Stainless Temperature Probe End to insert into the compression fitting.

    With the sensors I am using DS18B20, most come mocked up with a stainless probe end and water tight pig tale, like in the link in my first post. I have a bunch of bulk raw DS18B20 and i was thinking it would be cool to, use that weld fitting + the 6mm probe ends with my sensors and a little 3 wire connector on the end of each probe tube, so it would add very little bulk to the still part its welded to, and with the wire connector soldered - hot glued - shrink tubed, you can unhook the wires and really just pretend its not there for cleaning moving ECT.

    But that seems like a lot of Welding

    What do you all think?

  • Mine is kind of simple.

    image

    I use a 4" super dephlem (it has 4 couplings).
    1. is sensor
    2. is electric valve that's controlled by an Olddog controller
    3. is a push connect plug for quick and easy draining
    4. is the exhaust water or water out

    Pretty sure the electric valve could be in position 4 as well.

    4in super.jpg
    293 x 258 - 21K
  • There are many places a sensor can be added to the Dash 2 or comes standard with it. The thermowells are all setup for our 4mm probes though and i don't think the are drillable all the way to 6mm.

    There are 2 thermotees to measure water temp from the condensors included standard with the Dash series. They are also included seperately, so can be added anywhere you want to monitor water temp.

    We have tee's that include a thermowell http://www.stilldragon.com.au/stainless-4-x-4-x-3-bubbletee-with-thermoport/ that can be substituted for any standard tee to measure vapour temp anywhere in the plated section.

    We also have two ways to measure vapour temp above the reflux condensor in the reducer. You could use a torpedo reducer with thermowell or use a plain torpedo reducer with a 2" thermowell endcap.

    We have 180 or 90 degree bends that have thermowells built in, some of these also have 3/8th or 1/2" threaded branches that can hold a compression fitting to suit the larger probes.

    We also have weld in thermowells that can be included anywhere you can imagine.

    All this without you having to order custom parts which are also achievable. :-?

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • @Smaug said: There is a direct relationship between the discharge water temp of the dephleg and the head (vapor) temp with regard to optimal performance/collection speed/desired purity.

    I believe there is a relationship between the two. But to me that's like trying to figure out how fast my car is by measuring the airflow passing by. There are too many other variables to factor in when I only care about rpm's of the wheels.

    So I am only speaking from my setup and this is probably different from everyone else. Because there is a very "direct relationship" between vapor temp and ABV I choose to measure here. Then I only have to punch in this setpoint on my PLC and not have to worry about if the water flow is different today or if it is warmer or colder. The PID settings I use in the PLC take care it.

    Again I am not saying this is the only way to do it, but for my setup is the most logical and efficient.

  • Agreed, that is logical and is exactly how I set mine up in the beginning - by putting the sensor in the vapor path between the dephlem and the product condenser.
    I had minor swings in vapor temperature as the PID tried to keep it steady.
    By relocating the sensor to the water path inside the dephlem the vapor temp was rock steady - no swing at all. The swing was in the dephlem instead of the vapor temp.

  • I agree with you mostly, @Lloyd, but Wally has a the point I was trying to make... if you use the P-I-D paramters correctly, you should be able to get much finer control... but then again, you may be right, it may be easier to monitor the much more stable water temperature... hmmmm.... this requires thought...... it is not really like the speed of a regular car with the airflow, but one with a throttle stop on it that is always applying a certain amount of power to the wheels, and you have slowly changing wind speed... now, you can measure wheel speed (very accurate, but you do not get the predictive ability of knowing what is coming next) with measuring the wind, you sense the speed of the wind change before it has the ability to overcome the inertia of the car, basically, you can predict what the car is going to do.... Bottom line is that I believe either can work if properly tuned.... damn control theory class... I only got a C in that class back in 1993 or so, but it was so interesting..... would be a good paper for a mechanical engineer doing thermodynamics..

  • I have thermo wells above/below the reflux condenser, in the reflux condenser and other places on my column, after trying them all for the best result, I informed Lloyd who concurred with me that the best result and most stable control was with the sensor in the dephlegmater.

  • @olddog said: I have thermo wells above/below the reflux condenser, in the reflux condenser and other places on my column, after trying them all for the best result, I informed Lloyd who concurred with me that the best result and most stable control was with the sensor in the dephlegmater.

    What setpoint did you set the controller at for this olddog?

  • @Mickiboi said: What setpoint did you set the controller at for this olddog?

    The setpoint will be different for everyone. This was my point. It could be a different each run for the same person. It would all depend on the temp of the incoming water and flow rate. I can see how this would be the more stable place to monitor. There is more of a buffer with all the water. However this buffer would also decrease sensitivity and reaction time.

  • edited May 2014

    @Mickiboi for my 5" I had good luck with these settings (all in degrees C):
    Fores 43
    Heads 45 or 46
    Hearts 57 to 60

    My 4" super dephlegmator responded well with:
    Fores 60 to 62
    Heads 70 to 72
    Hearts 75

    I'm sure with successive runs I could fine tune that a bit.
    And @Wallybox is right, there are variables to be concerned about like power input, water flow and its temperature, etc... but if I'd run the same boiler charge and power level I could probably nail the settings and get very repeatable results.

    Note that my PID probe is inside the dephlegmator.

    Edit: Your mileage WILL vary.

    I inched up the PID a little at a time to find those numbers.

  • Thanks Lloyd. I thought the temps would have been lower than that, very interesting. Is your sensor mounted right at the top of the dephleg? Have you posted a picture of it anywhere?

  • @Mickiboi said: Is your sensor mounted right at the top of the dephleg? Have you posted a picture of it anywhere?

    Yes, scroll up about 7 posts on this very page.

  • Dohhhhh. I did see it but my mind has been else where lately. Sorry.

  • No problem, I also looked through 2 or 3 threads before I spotted it here =))

  • edited May 2014

    @Lloyd your flow is in the bottom and your return is at the top of the dephleg?

    Edit just looked at your pic again.

    Is this to stop air locks or does it just work better this way?

  • edited May 2014

    Stops air lock. Works great for me and countless others.
    At least one guy has disagreed and installed a bypass(?) of some sort but I've found it unnecessary. Maybe I should do the expense, install the bypass valve thing to prove him right or wrong but cannot find his thread now, sorry. His name is Swede on ArtisanDistiller. Not sure really if he is friend or foe. Really not sure.

  • @Mickiboi said: Lloyd your flow is in the bottom and your return is at the top of the dephleg?

    Edit just looked at your pic again.

    Is this to stop air locks or does it just work better this way?

    Yes. It is to minimize any air bubbles and also to mitigate potential siphoning. Counter flow is just not that critical as the dephlegmator has plenty of knock down power.

    Or you could install your own perge solution and plumb it for counter flow.

    StillDragon North America - Your StillDragon® Distributor for North America

Sign In or Register to comment.