Re: Ruby - How about a sight glass?

[Chris Wolcott]

If I remember my college days correctly, capillary action only occurs at 
the fluid/air interface.  If this is true, then only the size of the 
tube would really matter.  However I'm not sure what, if any, effect the 
higher pressure of the steam would have over the capillary action of the 
liquid.  I would think off hand that it would more than counter it, and 
the real problem with small sight glasses is the difficulty in seeing 
the clear water in such a small but clear tube.

> Geoff,
> I'd say Steve is hitting on the right question which is, does the effect of 
>capillary action occur primarily in the feed line, equally along the entire tube 
>path, or mostly at or near the surface?  My guess is that it occurs equally along 
>entire length of the water path