SpudFiles

Back in highschool chemistry we had these y fitting type things that drew a vacuum from the y part when water was run through the straight part. I was wondering if I got a plastic y fitting from the depot and ran a small air pump through the straight part would it be able to draw fumes from the y part?

The principle should apply. For suctioning things like gravel or mud people usually use some sort of venturi pump... also, steam can be used to draw vacuum as well.

c0rpse wrote:I was wondering if I got a plastic y fitting from the depot and ran a small air pump through the straight part would it be able to draw fumes from the y part?

Yes.

You can use an aspirator (which is what you are describing) with either water or air as the working fluid.

How well it works depends on the diameter of the straight tube, the size of the hole between the straight and the "Y" arm, the working fluid, amount of constriction in the straight part of the tube, and probably a couple other things.

A "T" fitting will work better than a "Y" fitting. The air is forced across the top of the T. Suction is created at the bottom of the "T".

How well this will work depends largely on what you mean by a "small air pump". A really small pump (like the one used in a fish tank) probably won't do much. A shop compressor should work pretty well. A vacuum cleaner (you pull air through the top of the T instead of pushing it) should work pretty well.

Of course, a vacuum cleaner could just be used directly.

Exactly what are you trying to do? Pull a serious vacuum or just remove flush small amounts of gas?

A decent water powered aspirator will pull down to about a pressure of 20 torr. That's 20/760 of an atmosphere final pressure. The actual limit pressure depends on the temperature of the water since the limit pressure is the vapor pressure of water at the water's temperature (roughly 20 torr at 60F).