Mini Induction heating help

Discussion in 'The Projects Forum' started by Chris15, Oct 26, 2011.

  1. Chris15

    Thread Starter Active Member

    Apr 15, 2009
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    Hello

    So i want to build a mini induction heater, liker really mini. Its for a tobacco vaporizer so it does not have to be hot at all. I know the basics of induction heating like the item to be heated must me magnetic or watever. (iron bar)

    Ive seen many induction heaters with copper coils and water running through them and tons and tons of circuitry. Can anyone explain to me in the simplest of terms how these things work and how i can build a very simple small one.

    I assumed i could get a transformer from a wall outlet and wire it up in step-up to a coil and it would work, but no.

    Also, i dont understand this part. When you short out (touch negative and pos) together it makes sparks, not good right. Why does a coil not explode batteries and stuff if its just a long circular short out.

    Thanks boiz
     
  2. Chris15

    Thread Starter Active Member

    Apr 15, 2009
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  3. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Induction heating only works when the thing being heated is metallic. It is the 'eddy currents' in the metal that causes the heat.
     
  4. wayneh

    Expert

    Sep 9, 2010
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    That circuit would indeed generate a strong and pulsating magnetic field (assuming the oscillator oscillates). The "receiver" - a piece of metal as noted - isn't shown and is an important part of the plan. Note that even the whopping 10A at 18V is "only" 180 watts, much less than a stove top.
     
  5. BMorse

    Senior Member

    Sep 26, 2009
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    To vaporize "Tobacco", it needs some pretty high temperatures, 300 to 350 degrees Fahrenheit would produce lighter, less dense vapor, above 400 degrees Fahrenheit tends to generate some tars with lots of active ingredients, so slightly below 400 F would be the optimum vaporization temp to produce a balance of pleasurable flavors along with a satisfying amount of active ingredients with a minimum amount of tars and unwanted compounds.....
     
  6. crutschow

    Expert

    Mar 14, 2008
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    Why use an induction heater? They are normally used to heat metals for various fabrication and heat treating processes. It will not heat tobacco.

    Just use a resistive heater. It's 100% efficient, easy to power and easy to control the heat level.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    I wonder if anyone actually puts tobacco into a "tobacco" vaporizer. Doubt it.
     
    Chris15, shortbus and BMorse like this.
  8. BMorse

    Senior Member

    Sep 26, 2009
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    The OP wants to use an induction heater to heat some metal that will in turn heat the "tobacco" :rolleyes:
     
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    You just made me dig out the Fluke IR Therm.

    Cigarette "at rest" (lit but no airflow) is about 375 degrees, when taking a pull, temp goes up to 610 degrees.

    I just posted that to add to everybody's "kind of useful trivia" knowledge bucket.
     
  10. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    That is Celsius.


    The vaporiser I built uses just resistors to heat the chamber. It is much simpler from the point of temperature regulation and build complexity than induction heating (you don´t want to use a thermistor inside the inductor´s field). Is there any reason why it has to be inductive?
    Also the enclosure should be non-metalic to keep the heat where you want it, which might be a problem at 200°C where the tobbaco vaporises.
     
  11. BMorse

    Senior Member

    Sep 26, 2009
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    1 AA NimH rechargable battery, some Stainless steel screen, and a couple of pieces of solid conductor (14ga) copper wire.... and a little ingenuity with a piece of hardwood and you have yourself a small, portable pocket vap that really works and compact.....:cool:
    VAP.jpg
    VAP2.jpg
    VAP3.jpg
     
    Last edited: Oct 27, 2011
  12. BMorse

    Senior Member

    Sep 26, 2009
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    the "at rest" temp is usually the temp you would want it to be near, at the 600+ degrees you are definitely sucking in a lot of tar and other compounds :eek:....
     
  13. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    That´s super cool :D
    So the air gets inside through that slot on top right and the screen is the heater?
    How long does the battery last?
     
  14. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    The vaporizer I have says to set temperature to around 288* F. and adjust from there. The electrical parts including the heater look like a temp controlled soldering station.:) But I never inhaled.
     
  15. BMorse

    Senior Member

    Sep 26, 2009
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    Yes, the air is drawn through that thin slot. The Screen is the heater, the copper wires are the battery connections, (Had to use large conductors to prevent them from heating up instead of the screen :rolleyes:)

    The "heater" gets pretty hot, really quick, and you only need to run it for about 5 to 10 secs per hit when the battery is fully charged, and you get about 4 to 6 uses out of each battery charge.... but then depending on the quality of the tobacco, who needs more than that??:cool:

    AA Rechargeable Nimh batteries are the best to use, since they can handle the large current draws, (plus Radio Shack usually has them on sale with a quick charger, that comes with a car adapter for maximum portability >> http://www.radioshack.com/product/index.jsp?productId=3899661&clickid=prod_cs )

    and for those who don't want to fuss around, here is one commercially available >> http://magic-flight.com/
     
  16. BMorse

    Senior Member

    Sep 26, 2009
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    The starting temp is usually low, and it also depends on the type of "tobacco" you use, some strains require more heat than others..... and yes, most of the commercially available ones that plug into AC outlets are nothing but soldering stations with adjustable temp settings that have been modified to be used for this purpose, I have made a couple of "weller" vaporizer myself for others. ;) and currently working on a "better" design built around a digital soldering station with a cool digital display, and utilizing blown glass tubes for the heat transfer:cool:

    speaking of which, anyone looking to buy a new soldering station should check these out, just got a couple of them and they are great for the price (44% off!!), they seem to have them on backorder now though... http://www.mcmelectronics.com/product/21-10115
     
  17. Chris15

    Thread Starter Active Member

    Apr 15, 2009
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    0
    So your just connecting the battery terminals to a screen, and this shorting heats it up??

    It does not HAVE to be induction heater to heat my "tobacco" i just was researching them and thought they were pretty cool, and thought of this.

    what other ways is there to thermoelectrically generate small amounts of heat. It does not have to be portable, i have wall adapters that i could use. i have a 19V 3.42A laptop charger that i can use. (i dont want to play around making my own 240VAC 15A input just yet :S )

    But for the induction part anyway, are they just a copper coil with AC current passed into it? then the magnetic field from that pulsing current gets the eddy currents into ur item (iron nail)

    so off the top of my head, if i make a 555 timer oscillator, connected to a MOSFET which then switches current (which is now AC) onto a small coil i have already wound will this create eddy current in my iron nail?

    the coil i have is 1mm thick solid copper wire. could a current to be passed through this be made from an old wall outlet transformer i have? i remember learning about stepping transformers, step up voltage lower current, and step down voltage and increase current. How do i wire a transformer to step down volts and up current with a 9V battery???


    Thanks, Chris
     
    Last edited: Oct 28, 2011
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