At 05:37 PM 6/20/2011, Harry Veeder wrote:
We all know a humidity probe was use to estimated the steam quality.
The probe
tells you the density of water in the air. This can be used with the
temperature
to calculate the steam quality by mass OR volume. Since the steam quality was
not measured directly by volume or mass so I don't understand all
the fuss...or
am I missing something?
If it is telling you the density of water in air, it's not exactly
functioning as the literature on the device says.
What the literature shows is relative humidity, which is the
percentage of maximum water that the air can carry at the given
temperature. What I'd expect this thing to show is 100% relative
humidity. The specifications on the meter used by Essen and Kullander
was +/- 2%. I really don't know how they got their figures, they
might be perfectly correct, but ... I don't understand it.
Wet steam will have a relative humidity of 100%, plus there is some
liquid water present. Dry steam will have ... what? The same?
My mind is boggled.
Yes, if we have a direct measure of water density in the air, that
will tell us steam quality, at some temperature. the problem, though,
would be, I'd think, measuring that if the water is present in liquid
form. My guess is that the meter only measures the gas.
But that would make a humidity meter totally useless for measuring
steam quality. Someone 'splain this thing to me!
