greenyppols
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need a special coolant pump??
Ive seen lots of discussion on vacuum pumps, coolers and such, and I searched around a bit here or may not know how to phrase the search....but after
reading a procedure that called for "the bottom condenser to be cooled with methanol, which is cooled with dry ice," it occured me that my standard
aquarium mag-drive water pump I currently use would probably quickly bite the dust. now that I think of it, I could just dunk the pump into some
methanol and see what happens to it, (probably nothing 'cause its just alcohol), but I'd rather see what anyone here has done or used. Do they freeze
up? or get clogged easy from chips of ice? explode from fumes?
so what do you more experienced folk use for such a thing? is it a standard "chemical pump" or what?
Thanks
[Edited on 1-4-2006 by greenyppols]
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runlabrun
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give it a whirl with a small amount in a controlled, safe environment (ie outside with fire extinguisher at the ready) and see if it works... wheres
your sense of adventure!!!
Dry ice wont easily form chips unless you smash it, its solid CO2, it sublimes. So just use large blocks of dry ice dumped in MeOH and your pump, once
again, give it a whirl where if it screws up you wont get hurt or hurt anyone or anything (apart from the poor pump, but hey, its inanimate!!)... if
you want, put the pump in a raised position above the dry ice but still submerged in the MeOH...
-rlr
[Edited on 4-4-2006 by runlabrun]
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greenyppols
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hahahaha @ sense of adventure. I hear what your saying, but I've learned that I do not heal as fast as I once did. Bruises last longer and a small
acid burn on the back of my calf (how the F**K it got there is beyond me!) bothered the hell out of me for a month. hehehe.
fire extinguisher?? wheres YOUR sense of adventure? 
(I know, I know..adventure, not stupidity. but I couldnt resist)
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runlabrun
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haha... nice...
Yeh well adventure with a pump and some methanol isnt to bad under the proviso of fire risks... i dont see anything wrong with true experimentation so
long as you have covered your ass (literally!)...
So as for your pump just use a small amount of dry ice and methanol (say no more than 2-3L??) and your pump out the back yard with nothing around that
can catch fire (or cant be easily extinguished) and stand back, switch it on and leave it go for an hour or whatever it will be used for and then turn
it off and see if the pump has sustained any injury... you might want to check also the heat generated from the pump doesnt evaporate the MeOH, but
with the dry ice there i dont think this would be a major deal... just use a rough check on volume (line on the external side of the container where
the initial level is) pre and post experiment to determine if you need a condensing system to prevent loss during operation...
all good?
and yeah, back of your calf? i have one just under my armpit.... try explaining that one...
-rlr
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Magpie
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Here's a couple suggestions:
Take a look at Little Giant Pump's on-line catalog.
JC Whitney offers a solid-state fuel pump for $35. You could call to find out it's minimum operating temperature.
The single most important condition for a successful synthesis is good mixing - Nicodem
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greenyppols
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Magpie - Actually, I have couple of those Little Giant pumps and hadnt considered using them as I thought them too damn big..but hey, it doesnt cost
me nuthin' to buy what I already have...
When I was messin' with distilling Nitric using Methylene Chloride using a procedure from Kings Chemistry, I dumped a few mls of into the plastic
bucket I using as a reservoir for the small aquarium pump I was using..I noticed how it sank in little bubbly clumps pretty damn fast and it looked
like they attached to the pump at the bottom (hard to tell looking thru the water at to the bottom)
After I was done and cleaning up, I noticed the pump was partially melted up. Was this the methylene chloride (which I have to assume would melt the
plastic given it dissolves PVC) or the nitric or both? That's what kinda prompted my question on pumps to use.
Thanks.
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Magpie
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I'm still assuming you need a pump for low temperature methanol (like -80C or some such).
Even if the pump is compatible with methanol at room temperature that doesn't mean it will give reliable long-term operation at this low temperature.
When I looked for pumps that were used at very low temperatures they were specialized (read expensive)cryogenic pumps.
All I'm saying is that if you want to go cheap you'll likely just have to try it and see. And you may ruin the pump finding out. 
Edit: Little Giant makes submersibles as well as regular centrifugal pumps with shaft seals. I would think twice about using a Little Giant
submersible in a flammable liquid. Or pumping a flammable in any ordinary pump for that matter. That's why I suggested the fuel pump.
[Edited on 22-5-2006 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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DrP
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Just a thought if your worried about the methanol (which is harmfull anyway) - can't you try a slightly more viscose oil or even IPA (flash point
is higher I think and at the very cold temp of dry ice it prob wont ignite anyway)
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