Bob,
It is simple to locate a flow meter low enough that it is never just
partly filled. I find it significant that we are not told where it was
located. Also, the stories of stain levels by an electronics expert
don't mean much. Jed suggested a world level stain expert had been hired...
On 8/8/2016 1:17 PM, Bob Higgins wrote:
Well, upon further investigation, I find that this flow meter has
"internal float level regulation" and is designed for measurement in
horizontal or vertical orientations. So, the issue with water level
may be moot because it appears this flow meter is designed to
compensate for water level (not sure if it compensates by changing an
orifice or what).
The meter is designed specifically for reading cold and hot liquid
water flow.
The flow meter is readable to nearest 0.5 liters of accumulated flow.
The lowest spec flow rate for this meter appears to be 1.6 m^3 per
hour (1600 l/h) to be within its specified maximum error of 5%.
So, the accuracy doesn't seem to be as bad as you suggest, but it is
fishy that the readings came out to 36000 kg of water every day when
the meter was readable in increments of essentially 0.5 liter (kg).
On Mon, Aug 8, 2016 at 9:32 AM, Bob Higgins <[email protected]
<mailto:[email protected]>> wrote:
The flow meter from that URL has nothing to do with heat
measurement - it is a standard turbine type flow meter. It has a
mechanical (gear ratio) calculation of flow from the rotor speed.
What I said still applys - it measures essentially the same water
speed whether the flow tube is half full or totally full.
It should be mounted vertically to insure a full flow tube and
hence accurate mechanical calculation of the flow.
An interesting observation is that this flow meter may actually
subtract any reverse flow from the accumulated total (reverse flow
measurement having been an issue with DGT). Whether it does this
or not would be determined by whether or not there is a mechanical
racheting mechanism in the gear train (probably not).
On Mon, Aug 8, 2016 at 9:04 AM, Jed Rothwell
<[email protected] <mailto:[email protected]>> wrote:
Bob Higgins <[email protected]
<mailto:[email protected]>> wrote:
What I meant is that the flow axis (also the turbine
propeller axis) should be vertical to insure that the flow
tube (housing the turbine) is fully filled.
I believe such turbines have a rotor (like a propeller)
with an axis coaxial with the flow tube and low blockage
spider supports . . .
Someone told me this is a brochure for this flow meter:
http://www.apator.com/uploads/files/Produkty/Przetworniki_przeplywu_do_cieplomierzy/MWN130-NC_MP130-NC/karta-mwn-nc130.pdf
<http://www.apator.com/uploads/files/Produkty/Przetworniki_przeplywu_do_cieplomierzy/MWN130-NC_MP130-NC/karta-mwn-nc130.pdf>
It is in Polish, so I can't be sure it is the right one. You
can Google translate the text. The first paragraph, for
example, comes out:
"The heat flow transducer with a horizontal rotor axis,
parallel to the water pipes with a low starting threshold.
Thanks to modern structural solutions - technology It
provides credibility indications and enables the
development of atypical systems in intermediate positions
without affecting its performance metrology. . . ."
Anyway, this shows an exploded view of the instrument, etc.
Perhaps this answers some of your questions.
- Jed
