Pressure Sensors & ION Eyes

[garfield at pilgrimhouse.com]

On Mon, 11 May 1998 20:07:05 -0700, goflo at pacbell.net wrote:

>I'll be taking you up on the speed controller assistance. Thanks.
>Need to decide whether to go with what I've got or just build a 
>bench from scratch. I'm taken with this Paxton blower notion -
>Really sounds like a winner. A/C motor controls are outside my
>hack so I'm all ears for your scheme.

Well, don't look now, but I've read some on the present "tek" on AC
motor speed controllers, and it makes me wonder if I'm really an EE. I
think I've got a pretty decent learning curve aheadOme.

>Lemme run this by you: Re pitot tubes - How 'bout sensing "static"
>pressure in a duct of known dimension and velocity with a pitot 
>tube. If you know both then flow is straightforward computation.
>High quality pitot tubes are relatively cheap (Dwyer). A range of 
>duct diameters is possible if necessary. Comment?

Well, yeah, that's what I always thot was the point of them Dwyer
two-piece pitot tubes, one to measure static, the other dynamic, but
again, you HAVE to assume the velocity profile of the plumbing you're
using, in order to get FLOW, don'tcha?

>Not to beat accuracy/repeatability to death, but I've found in 
>component testing that what you've got hung on the piece under test 
>(manifold, air straightener, whatever) makes way more than a couple
>of per cent difference - I doubt it'll surprise you that a lot of the
>"big" numbers you hear about are obtained with very "unrealistic" test 
>set-ups, to put it kindly.

Yeah, well you ARE way ahead of me on knowing the practicalities of this
game, as I have only played with a SF-300 on one single head (4 ports) I
was working on. That's why I said probably +-5% is gonna do it. But I've
also had the crappy experience of sending the piece to someone else that
also had a SF-300, and having them tell me my numbers were way off!!

>I once had the honor of being abused by Ken Sperrling (AFR)
<bozo story snipped> Ahhh, that's all goin under the heading of
politics/and-or those that deserve most of all the single-finger salute.
Geez, understanding and keepin yerself from foolin yerself is hard
enough, without these bozos coming along and saying they're fully
clothed and beautiful, when any damned fool can see they're stark naked.

I dunno, at my age I start thinking what caliber of ordnance would be
necessary to expunge the dildo from the scene. I've come to the
conclusion that fakes and charlatans are a natural percentage of the
population, and should be treated as such, just like any OTHER criminal
element. But, then again, I am kinda a curmudeon.

Gar