Hi Sarah,

I'd have to agree with Mark 110%.
We had two manual valves until the ammonia gas ran out one weekend and the
etch solution back filled the gas line.
Nothing like blue crystals in the gas line.

We use a Walchem W-150 pH Controller.
They have a newer model: W-320, quoted me around $1000 but, I have to go
through a local rep.

Here's their contact info:

Walchem Corporation
Five Boynton Road
Hopping Brook Park
Holliston, MA 01746
(508) 429 - 1110 Tel.
(508) 429 - 7433 Fax

Hans

Air Force Material Command - We keep them flying!
~~~~~~~~
Hans M. Hinners                                 WR-ALC/LYPME Bldg. 640
Materials Engineer                                      380 Second Street,
Suite 104
Manufacturing Eng. Sec.                         Robins AFB GA 31098-1638
912-926-1970 (Voice) 468 - 1970 (DSN)   912-926-7974 (Fax)
[log in to unmask]


> Hello everybody
> I would like to add a pH control system to my ammoniacal copper etcher
> that would open and close a vent based on the pH of the bath.  Does anyone
> know of a company that supply me with something like that?
> Thanks
>
>
> Sarah Boutwell
> Manufacturing Engineer
> Johnson Matthey Advanced Circuits
> [log in to unmask]
> 612-684-5079
>

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