apps engr at supplier asking back
whats the line dia and nominal velocity
001(780)465-9762
Fax/Msg(780)465-9762
-----Original Message-----
From: Steve McKenzie [mailto:mechproj@xtra.co.nz]
Sent: Monday, April 26, 2004 3:09 AM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] Flowmeter for hot Fluosilicic Acid
Hi Al
the magflow I mentioned is an electromagnetic flowmeter, and it requires
electrodes in contact with the fluid to make the circuit. It is these
electrodes that fail. Hastelloy C(4) is around 60% nickel 16% each of moly
and chrome, 3% iron and it fails in this application. Havent seen any signs
of SCC; just the rippled surface of corrosion erosion.
I was wondering about carbon as an electrode, or perhaps someone makes a
high frequency non-contact model using capacitive coupling across a plastic
membrane; not even sure if this is technically feasible.
No idea where to start with coupon tests; everything seems to fail.
Had wondered about using a peristaltic pump and computing flow from revs X
swept volume, but the manufacturers cannot find a suitable tube material.
The search continues:
Thanks
Steve
-----Original Message-----
From: Al [mailto:alwynk@shaw.ca]
Sent: Monday, April 26, 2004 7:53 PM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] Flowmeter for hot Fluosilicic Acid
geez thats a really tough one steve.
I'd be looking for an IRON CHROMIUM NICKEL alloy with >50% nickel content.
nothings gonna be cheap and I cant give you a good and quick answer.
My guess is the mechanisms gonna be SCC and the problems and answers are going be similar to the solutions for polythionic acid materials selection. Do you have some time to do some coupon tests? what about electromagnetic flowmeter.. wont be in the nasties.
Altecheng@shaw.ca
001(780)465-9762
Fax/Msg(780)465-9762
-----Original Message-----
From: Steve McKenzie [mailto:mechproj@xtra.co.nz]
Sent: Sunday, April 25, 2004 11:45 PM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] Flowmeter for hot Fluosilicic Acid
Hi there
I am having trouble finding a reliable flowmeter for HFA pH about 1, around 90 deg C, lots of solids. Its a killer brew - seems to attack anything hard and migrate through anything soft except vinyl ester and virgin teflon. Installation is at a Superphosphate manufacture plant.
Magflows have the Hastelloy C electrodes eaten away. Am dubious about ultrasonic - suspect inevitable solids deposits on the pipe wall will cause problems. Same for calometric. Mass flowmeters are a bit dear and the guts would rot out.
System is under pressure so I cant use a weir and level transmitter.
Was wondering about a bend meter with flushed DP tappings.
Any bright ideas out there?
Also pumps for same. Have tried Durco Hastelloy C (corrosion/erosion failure, Ash elastomer lined (migration of fluoride to shell). currently using Coro FRP - chemically OK but it will abrade/fatigue away
Cheers
Steve
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