Capillary pump ?

[Externet]

Hi.

What liquid in which diameter capillary tube of what material would rise the most ?

 

If the vertical rise for a given set is let's say 100mm; and at about 90mm of the capillary column the tube bends 180º downwards as siphon... ¿ will it drip ?

 

Miguel

[Dak]

Hi.

What liquid in which diameter capillary tube of what material would rise the most ?

the rise is caused by molecular interactions between the liquid and the tube -- as H₂O is the most polar molecule which springs to mind, id say that plain old water is your best bet for the liquid that would rise the most.

 

btw, the material of the tube is also inportant in determining how far the liquid rises, id immajine.

[Simpleton]

Don't realy know if 10 mm will do (as the drip may depend on the volume in the downward part of the tube) but dare to say that thirty or forty mm of downward tubing would have it drip for sure.

[Mr Skeptic]

The combination of tube and liquid with the strongest attraction between the tube and the liquid will rise the most. This should be the same as the liquid/solid that form the highest meniscus (with the edges upward).

 

The setup you described will only drip if the fluid level is above 80 mm (ie, the bottom of the tube outside the liquid lower than the level of the liquid).

[Newbies_Kid]

Suitable combination between liquid's viscosity and the column surface molecule create maximum surface tension and increase the crawling force (upwards). Since it is weight limited, it will rise higher in smaller tube.

[John Cuthber]

"If the vertical rise for a given set is let's say 100mm; and at about 90mm of the capillary column the tube bends 180º downwards as siphon... ¿ will it drip ? "

No, because, if it did, it would be a perpetual motion machine.