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Time & Temperature Sensor

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Mitch Newton, Feb 6, 2013.

  1. Mitch Newton

    Mitch Newton Member

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    Is this available? A sensor that sits on the stove that registers elapsed time and temperature. I'm thinking of a unit that could then be plugged into the computer to then plot a graph of time and temperature so that you would know exactly how your stove is running thru-out the day or night when you might be sleeping or away from home. Something like what the insurance companies are providing to measure your driving performance. My son is a high tech computer expert and I am thinking this could be developed pretty easily. Would there be a demand for this?

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  2. Joful

    Joful Minister of Fire

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    Yes. Google "thermocouple meter logging", and you'll find hits for dozens (hundreds?) of inexpensive thermocouple meters with various logging functions. Some can just be viewed on the meter (like mine), others can be plugged into a PC via USB or RS-232 (old skool!) to download the data. Most of the latter dump the data into a .csv file, which can be opened in Excel. Price range: $30 to $600'ish, but you should find something good enough for homeowner use around $100.

    It may pay to read up a little on thermocouples, if you're not familiar. Omega.com has the best intro literature. In short, you need to match your thermocouple type to the meter you're buying, or vice versa. Type-K is a pretty common all-purpose type, for stuff like this. You need all of your wiring, connectors, and meter to be of the same type, since you're measuring temperature by measuring the small galvanic voltage generated where the two wires (dissimilar metals) are welded together. Any other dissimilar metal introduced to the system generates errors, sometimes very large errors.
    Jon1270 likes this.
  3. TradEddie

    TradEddie Minister of Fire

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    It will be important to keep the logger part away from the heat of the stove, especially when using less expensive loggers. Not just that you would fry the electronics, but accuracy will be very poor if the logger is not at moderate temperatures. You can even get wireless loggers now that communicate directly with a PC.

    Things have come a long way from the first temperature data logger I used, it had a battery-powered motor that slowly dragged a roll of carbon-paper under a needle mounted on a bi-metallic strip.

    TE
  4. Mitch Newton

    Mitch Newton Member

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    Do you actually use one on your stove? What measurements do you get? Did it help you?
  5. Mitch Newton

    Mitch Newton Member

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    You are right Google comes up with hundreds. I am trying to figure out which ones would be best for a wood stove. Is there an internal flue probe that would stand up to the kind of heat in the flue? Reasonable cost?
  6. begreen

    begreen Mooderator Staff Member

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  7. WES999

    WES999 Minister of Fire

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    I have a Omega wireless thermocouple data logger to monitor the stove top and ambient temp.
    Here is a plot I saved from last year.

    http://www.omega.com/ppt/pptsc.asp?ref=OM-CP-RFTC4000A&ttID=OM-CP-RFTC4000A&Nav=

    You need a receiver as well.

    It can measure stove top temp or flue temp, you just need the correct thermocouple.
    I have a flue temp thermocouple that is rated to 2000::F.
    Reasonable cost? Um, not so much.

    burn time1.JPG
  8. Joful

    Joful Minister of Fire

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    Yep... I tried those. Burned out two in three months, using as catalyst temperature probes (admittedly hotter than flue temps). The plastic junction between the probe and the wiring is reported to be the weak spot, according to Omega tech support. If you go this route, order the probe way long, and bend it to your required length. The extra length puts more of the probe outside the hot space, allowing the plastic bit to stay cooler.

    I've had much better luck (so far) with this one: http://www.mcmaster.com/#39095K96
  9. ddahlgren

    ddahlgren Feeling the Heat

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    In your graph are those flue or stove temps? It might be interesting to have 2 channels and you could end up with an efficiency and get a good idea of when to reload.
  10. WES999

    WES999 Minister of Fire

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    The top curve is stove top temp, the bottom curve is ambient room temp.
    This data logger has one external thermocouple input (stove top) and one internal thermocouple to measure ambient temp.
  11. Mitch Newton

    Mitch Newton Member

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    WES999, The graph is pretty cool. Can you post pictures of the unit on the stovetop? Is it wireless?
  12. Joful

    Joful Minister of Fire

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    Umm... scratch that. Found one of these dead this morning. ;lol

    Three thermocouple probes ($35/ea.) in about four months... I need to find a better solution!
  13. ddahlgren

    ddahlgren Feeling the Heat

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    Try EGT.com they make them for serious race cars that can not only burn them up but shake them apart as well..
  14. Gabby12

    Gabby12 New Member

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    Not to rob this threads intent - and if doing so I can start another thread.

    I am new to using/burning a stove with only 1 week under my belt but one thing that has been on my mind (expecially with not knowing the stove that well) is a way to monitor the stove temp. with more of an intent to be able to have an alarm point set at a point where I would have time to shut down the air so to not let the stove over fire.

    I am sure in tiem I will have a better feel for what kind of wood/air ratio will come up to a certain temp. but without being in room with stove while burning I think there is a lot of room for error and getting the stove too hot or on the other hand not having it hot enough to burn cleanly.

    At work we use an automation system tomonitor everything and having these high/low temp. alarms is a huge factor to us knowing something is wrong and giving us a heads up before things get too bad.

    I would think a digital read out would be more neccesary and handy for my intentions as opposed to the downloadable trend in which to see the temps.

    I would think just monitoring the stove top for low and high would be my need - at this point.
  15. Mitch Newton

    Mitch Newton Member

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    Not robbing the thread at all. I think all that is relevant to my post.
  16. Gabby12

    Gabby12 New Member

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    Saw this
    Which seems to fit the bill but not real keen on wire and senor tubes running all over the place.
    I'm sure there are othter option.

    Question - Is it better to monitor flue temp or stove top temp if only doing one?
  17. Gabby12

    Gabby12 New Member

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  18. Joful

    Joful Minister of Fire

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    Seems EGT.com loads as some sort of Asian Entertainment site. I assume "EGT" is an acronym for Exhaust Gas Temperature? Maybe a good idea, if they make 1/16" to 3/16" probe diameters at least 3.5" long. I suspect most EGT's are threaded fittings, though.

    edit: Just found TheSensorConnection, which seems to have a lot of their stuff.
  19. TradEddie

    TradEddie Minister of Fire

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    The cost of something reliable enough to depend on would be prohibitive, so consider yourself the first line of protection, and the alarm as a backup. It's hard to accidentally overfire a stove unless you get distracted by something else, so my backup is that I set the microwave timer for 10 minutes whenever I reload. At work, I
    use monitoring and datalogging equipment costing up to 6 figures, but at home I use a $20 stovetop thermometer with a paperclip to show the maximum temperature.

    TE
  20. WES999

    WES999 Minister of Fire

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    Picture 170.jpg Picture 170.jpg
    Have you looked at this one? Good to 2000::F and made from Inconel 600 alloy.
    http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=22
    How hot does the cat probe get?

    I put together a monitor/alarm for stove top an flue temp.

    This company also has a monitor /alarm all ready to go.
    http://www.auberins.com/index.php?main_page=product_info&cPath=17&products_id=292

    I disagree,I think $100-$150 is not unreasonable.

    Yes stoves take some time to overfire but...
    You can over fire your flue in about 3-4 minutes.:ZZZ
    View attachment 92602

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