At 12:14 AM 6/23/2011, Mark Iverson wrote:
Abd wrote:
"One page 6, the list of humidity probes begins. The "robust" probe,
part number 0628 0021, is rated
to 180 C. The measurement range extends from 0 to 100% RH. However,
the accuracy is not rated above
98%. Basically, the accuracy is 2%, from 2 to 98% RH."
Abd, give me a link to what you're reading because on the webpage
that Galantini provided a link to
on NET website in his response to Krivits visit, here are the specs
for humidity accuracy:
+-2.5%RH (10...90% RH)
+-3.5%RH remaining range
And the usable temperature range is "-40C...+150C" and the usable RH
range is "0...100% RH"
I believe that I gave the link. There is more than one meter that has
been referenced, and they have different specifications, leading to
lots of confusion. I don't have time to look back right now. When I
referred to page 6, I believe that this was after having given the
specific reference.
What Mark wrote is not really different, though. The "usable range"
does go up to 100% RH, as I wrote. The problem is?
Wet steam is, in terms of g/m^3, above 100% RH. The meter does not go
above 100%, apparently. Don't you see that?
Abd wrote:
"But the meter has no capacity to measure that excess water, it
would simply peg at 100%, it seems.
I see no sign, anywhere, of any expert opinion that RH meters have
any application to the
measurement of steam quality."
Yes, as I've been trying to explain all along, once you get to
100%RH, all remaining water will be
in the form of liquid water because at the given temperature and
pressure it is now saturated and
can no longer support further water molecules as vapor.
Right.
I've already answered your question as to HOW one can calculate that
portion that is liquid water...
As I recall, you left out a critical factor. The value provided by
the RH meter is useless, once we know that we have steam at the
boiling point, it will give us no information at all on the
percentage that is liquid water. All steam, wet or dry, will show the
same temperature and RH.
