1281371269
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Kipp's Apparatus
Thought people might be interested to know that Rapidonline.com (an educational supplier) have started selling HDPE Kipp's apparatuses for between
£11.99-£16.99 depending on capacity. Certainly much cheaper than buying a glass one, and probably just as useful.
http://www.rapidonline.com/Educational-Products/Science/Labo...
I'm planning on ordering myself one and I'll report back when I've had a chance to test it, but they look good, even if the people who write the
descriptions don't quite understand how they work.
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mr.crow
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Looks like a Hookah 
That actually looks very useful in the lab. I would never use a glass one, too large and expensive.
They actually mention using it for H2S, doesn't sound too safe
Double, double toil and trouble; Fire burn, and caldron bubble
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not_important
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That was the traditional use, producing H2S for the inorganic analytical lab/classes. Hydrogn and CO2 were the other common gases, but less common
than H2S.
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crazyboy
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That looks poorly designed, what would prevent H2S or whatever gas you are producing from simply bubbling up the thistle tube when the stopcock is
closed? Those little bubbles? No way, the second it starts getting pressure the gas will escape out the top.
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not_important
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That's an old design, been in use for a century and a half or so. The increasing gas pressure forces the acid back up into the upper bulb, removing
it from contact with the sulfide.
A quick Web search would have shown you that, plenty of sites explain the operation - say here http://en.wikipedia.org/wiki/Kipp%27s_apparatus
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The WiZard is In
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Quote: Originally posted by not_important  | That was the traditional use, producing H2S for the inorganic analytical lab/classes. Hydrogn and CO2 were the other common gases, but less common
than H2S.
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Ah memories of when you could smell the college chem building
two blocks away.
Found memories of bubbling H2S into ones unknown
white precipitate - brown precipitate - black precipitate - yellow precipitate
— mud.
Precip the sulphates - dissolve out the carbonates (HCl).....
classic wet chemistry.
djh
----
The Chymists are a strange Class of Mortals, impelled
by an incomprehensible Impulse to take their Pleasure
amid Smoke and Vapour, Fume and Flame, Poison and
Poverty - Yet among all these Evils, I seem to live so
sweetly that may I die if I would change places with the
Persian King!
Johann Beccher
Physica Subterranea, 1703
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digitalemu
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| Quote: Originally posted by Mossydie | Thought people might be interested to know that Rapidonline.com (an educational supplier) have started selling HDPE Kipp's apparatuses for between
£11.99-£16.99 depending on capacity. Certainly much cheaper than buying a glass one, and probably just as useful.
http://www.rapidonline.com/Educational-Products/Science/Labo...
I'm planning on ordering myself one and I'll report back when I've had a chance to test it, but they look good, even if the people who write the
descriptions don't quite understand how they work. |
That place seems to have some other. nice educational items aside from the Kipps apparatus
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digitalemu
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| Quote: Originally posted by crazyboy | | That looks poorly designed, what would prevent H2S or whatever gas you are producing from simply bubbling up the thistle tube when the stopcock is
closed? Those little bubbles? No way, the second it starts getting pressure the gas will escape out the top. |
Probably does not create enough pressure to get through the trap directly attached to the thistle tube (that bendy part right under the funnel). Keep
in mind that these are not industrial items and are not designed to produce large or dangerous amounts of H2S or other gasses. The trap can only hold
back so much pressure and the thing is not designed to hold gasses for long periods of time though I imagine a small amount would be contained for a
while.
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1281371269
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The apparatus has arrived!
I haven't yet had a chance to properly test it, but I already have one concern. The apparatus should have some kind of fitting between the middle and
bottom domes, to stop the base falling into the bottom dome. My version doesn't. This rather defeats the point - if the base can fall through into the
lower layer, gas production won't stop at increased pressure. I've emailed Rapid to ask if a part is missing, but I think it might be a design flaw.
Can't help thinking that this might be to my advantage, however. It won't be particularly tricky to make my own fitting, and Rapid might give me
compensation. Ah, the joys of ordering things online!
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Renaissance Man
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Sorry to bump a 6 month old thread, but I am thinking of getting one of these. I was just wondering how your problem turned out. I couldn't quite get
a picture of exactly what was wrong with it from your description. Did the generator work? If not were you able to get reimbursed/fashion a
replacement part very easily?
And lastly, how well do you think this would stand up to Chlorine gas, is the plastic tough enough? There is a nice looking glass one up on ebay right
now for 110 USD but given the prices on rapid I can't justify glass. The only advantages I see about getting glass over plastic is chemical resistance
and the ability to see what is going on and how much reagent is left. While It may be a bit superficial plastic looks ugly, the glass versions are
much more sexy. 
Hmmmm, "Greener synthesis of acetylsalicylic acid kit" ages 11 and up. It comes with 50 ml acetic anhydride for 73 pounds, interesting but diffidently
not economical.
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1281371269
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It's made of HDPE and the stopcock is PTFE, so both of those should be fine. There might be some difficulties with the plastic tube, but you could
easily replace that with a PTFE one from ebay.
The problem is that there is no fitting between the middle and bottom spheres, just a hole. That means that powders can simply slide down into the
acid reservoir, defeating the entire point of the apparatus (because gas production would not be stopped by an increase in pressure). I have managed
to semi fix that by wrapping a large amount of PTFE tape around the middle (liquid delivery) tube at the point where it goes from the middle to the
bottom sphere, filling up the gap to the extent that liquids can get past but larger solids particles can't. The only issue with the fix is that you
need reagents in chip form rather than in powder form. I've never seen KMnO4 chips, so you might be better with a glass apparatus if you want Cl2. On
the other hand for CO2 or H2 it should be fine.
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peach
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I clicked this about to say 'nah... you want a funnel and a flask', but for £12.... darn! They'd definitely be worth it.
I have quite a few gas flasks, heads and equalizing funnels (which have run my bank account overdrawn and are super fragile), but that still looks
good. Particularly given the price and that it should be far harder to damage.
Might not be as brilliant as glass, but £12.... that's about three beers and a bag of peanuts in London town
HDPE is the most chemically resistant plastic you'll routinely get before fluoropolymers - and I expect that'd cost about a grand if it were moulded
out of PTFE (seriously, moulded PTFE bottles are about a hundred pounds each).
I might get one despite all the glass. For the same price as the glass, you could have a line of these set up and grab each gas on demand.
Edit: Keep in mind that for the gas to get to the trap at the top, it has to push all the acid in the bottom chamber back up the thistle funnel, into
the top chamber, then bubble through that to the trap. The big chamber at the bottom is there for that reason.
A quick check of the chemical resistance says HDPE has little to no damage over 30 days exposure to 10% dry chlorine and 'some effect' over 7 days if
the gas is damp. I doubt it'd be too happy with a concentrated volume that is also damp, but these guides always depend on duration as well.
John
[Edited on 14-1-2011 by peach]
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not_important
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| Quote: Originally posted by Mossydie | ...
The problem is that there is no fitting between the middle and bottom spheres, just a hole. That means that powders can simply slide down into the
acid reservoir, defeating the entire point of the apparatus (because gas production would not be stopped by an increase in pressure). ...
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Kipp's usually used iron sulfide lumps, marble chips, mossy zinc, or similar lumpy solids - thus little problem with solids slipping down into the
reaction bulb. Sometimes a loose wrap of asbestos or glass wool was used around the liquid delivery tube, similar to your use of PTFE tape; it was
really rather open, not packed into place.
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1281371269
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Mossy zinc? Sounds good to me!
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peach
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I used to go to a school called Mosslands.
They built a gigantic girls secondary school over it when I left, affectionately known by my brother as 'the pussy farm'.
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not_important
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At one time lab supply places would carry a mixture of bleaching powder (sort of calcium hypochlorite) and Plaster of Paris formed into rough cubes,
intended for use in Kipp's apparatus for chlorine production. Solved the problem of retaining the powder that bleaching lime normally appears as, the
plaster content kept most of the reacted stuff up top and that which fell had already given up ts CL2.
Another if rarer item was a similar composition of calcium sulfite and plaster, for SO2 production.
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Mush
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| Quote: Originally posted by not_important | At one time lab supply places would carry a mixture of bleaching powder (sort of calcium hypochlorite) and Plaster of Paris formed into rough cubes,
intended for use in Kipp's apparatus for chlorine production. Solved the problem of retaining the powder that bleaching lime normally appears as, the
plaster content kept most of the reacted stuff up top and that which fell had already given up ts CL2.
Another if rarer item was a similar composition of calcium sulfite and plaster, for SO2 production.
|
Great suggestion! I managed to find the original paper for its preparation.
J. Chem. Soc., Abstr., 1887,52, 442-450
10.1039/CA8875200442
Method for Obtaining Chlorine from Chloride of Lime, using Kipp's Apparatus. By C. WINKLER (Ber., 20,184-185).
Dry chloride of lime is intimately mixed with burnt gypsum, and moistened to such a degree that it can only with difficulty be rolled into balls
between the fingers. It is made homogeneous by powdering with an iron mortar, and beaten into an iron frame 10 to 12 mm. high by means of an iron
mallet. It is then covered with a piece of oil- cloth, and submitted to great pressure. The plate of chloride of lime is then cut into cubes whilst
still in the frame, taken out whole, and dried as quickly as possible at 20 C. The cubes are then preserved in well-closed vessels. It is used in a
Kipp's apparatus with hydrochloric acid (sp. gr. 1.124) diluted with an equal volume of water. The acid must be free from sulphuric acid. N. H. M.
I am planning to buy a Kipp's apparatus from aliexpress. The problem is that the side joints ungrounded. Is there a way to sand it without a pro
kit?
https://www.aliexpress.com/wholesale?catId=0&initiative_...
This is the pro way to do it.
GROUND GLASS JOINT GRINDERS
https://www.abrimagery.com/store/index.php/ground-glass-join...
Female Joint Grinding Bit Set
https://www.abrimagery.com/store/product_info.php/female-joi...
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