Pressure Sensor for Flow Bench

[garfield at pilgrimhouse.com]

On Fri, 8 May 1998 05:44:46 -0400 (EDT), Alain Toussaint
<alaint at boisfrancs.qc.ca> wrote:

>> BUT,
>> just about all the blower motors all them FlowBench guys use now are
>> AC/DC motors that can be easily thyristor controlled
>
>i think a word must be said about efficiency of the fan used there

But, but , but it's already being done. This is how all the Quadrant
Scientific flow benches work, already. Since you are controlling the
motors in closed-loop, with diff. pressure drop across the DUT as your
set point, as long as the blower motors don't LARGELY go to pot, you
don't really care if the efficiency isn't completely constant over the
range you're varying the rpm. The other thing to observe is that these
blower-motors aren't like single stage rotary or squirrel-cage fans;
they're actually more like lil 2-stage turbines inside.

Maybe it's like EGOR and ION, they may seem like hard problems if we
were approaching them for the first time, and starting from first
principles, but an existence proof is worth a ton of speculation, and
once there's proof that it's been done, and that cheaply and
practically, then we can dispense with worrying about the "order" of
certain effects and issues, and just go DO IT. Thas eXactly why I
mentioned the Quadrant Sci stuff.

Not tryna say that the issue of blower efficiency isn't REAL, just that
given commercial implementations built around varying the blowers under
thyristor control, it just can't be a show-stopper. Unless them guys use
a special sauce the recipe for which is currently a trade secret, ala
Kernel Sanders. [BTW, I don't ever recall hearing of anyone successfully
reverse-engineering his chicken, have you? Now THERE'S an example of an
effective and well kept trade secret. Whew! Humbling, idn't it?; to
think that what stuff we're doing here is easier than tryna duplicate
someone's cooking yer fond of. Heh].

Garfield
(confirmed birdatarian; if you know the Kernel's recipe', lemme know! I
gotta great zuccini-bread recipe' I'll trade ya. B)