Sciencemadness Discussion Board

Rubber Bellows

bfesser - 28-7-2009 at 11:02

Does anyone know where one can purchase bellows, such as those shown in the following video:

http://www.youtube.com/watch?v=B-Y7MlTk2k8

I've been unable to find them anywhere.

Mr. Wizard - 28-7-2009 at 12:05

It looks like a blood pressure cuff bulb. You can buy one at a medical supply store.


Here is a link for some from as cheap as $3.
http://www1.shopping.com/xDN-health_aids--blood_pressure_mon...



28933082-100x100-0-0_Blood_Pressure_Baumanometer_Inflation_Bulb_Valve_P.jpg - 1kB

bfesser - 28-7-2009 at 12:14

Yes, the lower part is much like one of those bulbs, but it pumps air into the upper inflatable chamber, to keep pressure on the column.

Mr. Wizard - 29-7-2009 at 09:52

Quote: Originally posted by bfesser  
Yes, the lower part is much like one of those bulbs, but it pumps air into the upper inflatable chamber, to keep pressure on the column.


Put a T fitting on the line and put a balloon on it or a PET plastic bottle and a cork. The pressure buffering isn't really needed, as you will store pressure in the compressed gas above the column. It's more eyewash than anything else. A rubber hose would do just as well. I'll bet it's main function is to keep the pressure from going too high, rather than too low.

bfesser - 29-7-2009 at 10:03

Good suggestions, thanks. Still would be nice to find one...

smuv - 30-7-2009 at 03:58

I am not sure how I feel about the technique of that video. First usually it is a good idea to layer the column cotton/sand/silica/sand. The bottom layer of sand is so that there is no silica in the taper at the bottom of the column which can mess up bands (though less important for very narrow columns). The top layer of sand is very important (IMO) it makes it so the solvent above the silica doesn't dissolve some of what is loaded onto the top layer of silica (as well as protecting the top layer of silica from being disturbed during the addition of eluent). The top sand layer gives cleaner separations and less streaking/tails.

[Edited on 7-30-2009 by smuv]

bfesser - 30-7-2009 at 09:19

Yeah, the technique in that video are horrible. I'm just interested in the bellows idea.