[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Avoiding Dumping CO2

>     To: Aquatic Plants Digest <Aquatic-Plants at actwin_com> 
>     Subject: Re: Avoiding Dumping CO2 
>     From: Wright Huntley <jwwiii at pacbell_net> 
>     Date: Thu, 23 May 2002 21:16:17 -0700 
> [snip] 
> Once flow is turbulent, the orifice is essentially a *flow-rate* 
> regulator with only minor sensitivity to inlet pressure. Trying to 
> adjust the flow with that inlet pressure is not a really good idea, 
> IMHO. Set the inlet pressure to the needle valve to be plenty high 
> enough to assure 100% turbulent flow (typically 10-30 psi), and set the 
> needle valve (now in full turbulent flow) to set the rate of CO2 
> injection into the tank.
> OK Bob, now that I have contributed my own "arrogant stupidity" I think 
> I'll put my:
> Flame Shield <UP>
> Wright

I only flamed TW because he was ridiculing Dave without having a clue what
he was talking about.
Thanks for the good explanation (although your mention of "Reynolds Number"
brought back memories from 15 to 20 years ago trying to implement complex
gas flow calculations on an 8-bit microprocessor in assembly language

IMHO, the important points for our application are 1) we are regulating the
*flow*, not the pressure  2) the metering valve should be operated with a
sufficient pressure drop that it is operating in its nonlinear range  --
relatively non sensitive to changes in input pressure.

Best regards,