Low density fluids

[Katharina]

Hello All,

I am looking for fluids with densities much lower than the density of water. I have got the idea to measure very small differential pressures in an u-tube with them.

Many thanks in advance,
Katharina

 

[btrueblood]

Oils (vegetable and mineral), paraffins (heptane, hexane, gasoline, kerosene), alcohols (ethanol, methanol), acetone.

 

[StoneCold]

There is a device out there that does this already. The tube is on an angle so small pressure changes are exagerated. I can't remember the name of the device.

 

[25362]

They are called inclined-tube manometers. Frequently used to measure draft in fired heaters, and very small pressure differences. A google search would show numerous sites.

 

[quark]

Manometer (inclined manometer) oil used in HVAC systems has a specific gravity of 0.83. With the advent of magnehelic technology and also evaporation of this oil during fumigation of areas, inclined manometers are becoming obsolete atleast in pharma industry.

 

[25362]

http://www.dwyer-inst.com/htdocs/pressure/ManometerIntroduction2.cfm

 

[JStephen]

I think you'll find that it's hard to get liquids that are a LOT different from water, or at least enough to make a significant difference in a manometer.

I believe you could rig up a manometer with two fluids where the difference in densities did the measuring, which would be more sensitive (and more complicated).