pH control / titration curve

[trotski]

I've thinkin' a lot about a smart regulation of an actuated valve related to the titration curve os an acid/base equilibrium but without success.

My procees requirementes are to remain the pH in an SP value and vary the ammount of acid... Can anybody give me a suggestion?

 

[itsmoked]

Well you have your work cut out for you... PH is possibly THE hardest thing to control. I have been thrashed by it myself.

Check Omega's offerings and their technical dissertation on the subject. Note that a controller that would cost $150 to do all kinds of temperatures costs $800 to do pH.

http://www.omega.com/toc_asp/subsectionSC.asp?subsection=DD02&book=Green

http://www.omega.com/techref/ph.html

pH Control: A Magical Mystery Tour

http://www.omega.com/techref/phtour.html

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Ashereng]

Also, pH is on a logarithmic scale, while most controllers are not. That would also add to the complexity?

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[danw2]

ISA published a book, aptly entitled "pH control", by Greg McMillan, in the mid 1980's. Used copies are available from half.com and used book vendors.

ISBN I have for the book is 0876647255

Dan