Cavatica
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Stirrer/hot plate temperature probe question
Hi guys, I was looking at this hot plate magnetic stirrer (looking to purchase one), and it says in the manual that the temperature probe must be
connected and submerged in the liquid in order for the hot plate to work. This strikes me as weird, as unless you are simply boiling a solution in an
open beaker, you would need a boiling flask with a side arm for the probe, which would increase the risk of leakage and contamination. Then again, I'm
new to these stirrer units, and have no idea whether this is commonplace, and you just go with the side-arm solution, or if there is som kind of
work-around that everyone knows about. I would be grateful for any feedback on this potentially stupid question!
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CHRIS25
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Don't buy it. This set up is the most ridiculous of all apparatus ever designed, trust me.
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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Cavatica
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Thanks CHRIS25, good call!
Btw, any suggestions as to a good stirrer/hot plate?
[Edited on 13-2-2015 by Cavatica]
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gdflp
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Depends on your budget, but I would go for a used name brand rather than a new Chinese one. IKA, Corning, Fischer Scientific, and VWR are all good
brands. Personally, I have a 10in.x10in. Fischer Isotemp that works great as my main hot plate, but it was expensive at around $250USD. I also have
a rather "used" Corning PC-351 and Thermolyne Nuova II that I use when I need more than one for an experimental setup. All of them work fine, but I
find the Nuova II to be a little weaker during both heating and stirring. I love the PC-351, the previous owner just didn't show as much TLC so it's
a little beaten up.
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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I have a Bibby quartz halogen stir/hot plate. It cost about $240.00 new over 10 years back, and I have never regretted buying. Quartz halogen heat
lamp is quick responding, prefer it for quick changes in heating (kind of like difference between cooking with an electric or a gas range!).
Has a plug in back for using a PID or other temperature control-
http://www.triadsci.com/?site=preowned&item=4583&men...
[Edited on 13-2-2015 by Bert]
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Zombie
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Am I correct in assuming the PID can control the temp of the plate?
In essence bypassing the surface Temp. sensor, and using the PID / thermocouple as the primary Temp. control.
[Edited on 14-2-2015 by Zombie]
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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PID (and possibly a high current relay) can cycle the heat on and off, you place the thermocouple at whatever part of your apparatus you wish to
control (water bath, still head, reaction mixture) and the PID learns response time of system, anticipates when to switch heating on/off.
http://castboolits.gunloads.com/showthread.php?181319-Pid-Co...
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Zombie
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I have several PID's set up on different projects. I'm a HUGE fan of "fuzzy logic". (probably already guessed that).
I was just curious as to why the plate would have a PID in/out? vs a built in thermocouple port.
Either way I love the quartz plate idea. It's one I have not come across till now.
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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Cavatica
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Great, guys, thanks a lot for the input!
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