Sciencemadness Discussion Board

interesting sep. funnel adaptation

Pyro - 12-10-2012 at 09:21

last week some of my new toys arrived :)
a 50 cm vigreux column and a few sep. funnels.
the interesting thing is that the sep. funnels have a small horizontal groove in the ground glass top, just deep enough to make a small opening, end the stoppers have a vertical groove from the bottom to the middle. it took me a while to figure out what they were, but then when i was washing them it cane to me! if you align the two cuts they form a small opening so that air can get in the body of the sep. funnel so that the liquid inside can drain out. and if you want to invert it you turn the stopper so that the cuts are not aligned and it's water/chemical proof.

Has anybody come across this before?

sep funnel 1.jpg - 183kBsep funnel 2.jpg - 185kBsep funnel 3.jpg - 178kB

Ephesian - 12-10-2012 at 09:32

Pretty cool euh? Sep funnels have come a long way :)

Hexavalent - 12-10-2012 at 09:32

Yea, I once had a few density bottles that had them. I only noticed it until the iodine I had in one of them started coming out of the opening!

Dave Angel - 12-10-2012 at 09:44

I wonder if the intended purpose of the adaptation is to prevent pressure build up from volatile solvents and gas-evolving reactions during shaking. An adaptation to save one the effort of taking the stopper out seems a little excessive!

Pyro - 12-10-2012 at 12:04

nope dave angel. whatever you are using would leak out. I think it is so you can let something drain out without taking out the stopper. for something like, say:Br2

kristofvagyok - 13-10-2012 at 11:24

Yep, we got a few like that in the lab, but I never liked to work with them.... If you work fast and you miss the right position then your reaction could easily end on you.

Pyro - 13-10-2012 at 11:45

odd. seems an eastern european thing. i got these from poland. nobody else seems to have heard of them!

mr.crow - 13-10-2012 at 20:24

I kind of like it. Don't have to take the stopper off while separating. But then again there are two things to screw up instead of one (the stopcock being open).

That cut in the glass looks really nasty and would weaken the joint. Don't want the top snapping off while using it!

My 1L crummy Bomex funnel was advertised as having something like that but didn't. Maybe the ebay store changed their supplier.

Dr.Bob - 19-10-2012 at 07:31

Cute, I have seen similar things a few times before, but not often, and mostly on custom made items. But this one is different that what I have seen, which is usually two holes that have to line up. A few glass stopcocks I have seen have those types of holes drilled into the stopcock itself, I guess to make a 3 way from a 2 way or such.

Pyro - 19-10-2012 at 07:39

True Mr crow. But luckily you don't put the joint of a sep funnel under extreme conditions like you would a distillation joint, so i hope i will be fine.
but i am quite pissed off at the seller for selling these as new, but it was less than 10$ for two so even if I lose them I will be ok.

Salmo - 24-10-2012 at 23:48

Useless, gas is evacuated from the main valve just bringing the funnel upside down.

Pyro - 26-10-2012 at 07:34

we (at least I did) meant when it's right way up you can open the stopcock without taking off the stopper. normally it would build up a vacuum and flow very slowly and unevenly or even stop