Ideas to purge/dry fluid from reservoir system.

[CanosSSCS]

Hello,

I am having issues with completely purging my system after use. Residual fluid seems to settle along crevices in the tank, lines, fittings. I am currently using CDA to purge but there always appears to be extra fluid left behind. For sizing, the tank holds about 300 ml, with 1/4" ID, all in all about 400 ml in the entire system when full.

Any advice as to how I could approach this problem? tips on how to dislodge residual fluid from the tank/lines? Much appreciate it.

 

[btrueblood]

How dry is dry? To get rid of the last drops after the first purge, you might need to pull vacuum then purge, repeat. This assumes a liquid (like water) that will boil at room temperature and low absolute pressure. Might need to apply heat to the air purge to help. The vacuum causes fluid in crevices to vaporize, tending to draw that liquid out of the crevices. But when the system returns to atmospheric pressure, the liquid will re-condense; purging then removes the now exposed fluid by physically pushing it out or by drying it on the surface. It's possible that during vacuum application, the boiling fluid will pull heat from the walls of the system, and some of the crevices could actually see temperature drop to the freezing point of the fluid or below - if that can happen, having a way to apply heat to the walls or purging with heated air can help.

 

[1503-44]

What fluid?

It isnt easy purging crevices, as you can't develop a pressure differential.

 

[CanosSSCS]

The working fluid is water, sometimes koolance

 

[Compositepro]

CDA: Child Development Association? I think not. Using undefined acronyms is very irritating and unprofessional.

Baking your system at 250F is the fastest and most reliable way to dry it. Pulling vacuum to below the boiling point of water at ambient temperature does the same thing. If the vacuum does not cause boiling it is not very effective at removing water from crevices.

 

[Latexman]

Cold Dry Air?

Good Luck,
Latexman

 

[LittleInch]

Flush it with mono ethylene glycol (MEG)

Try hot dry air?

At 300ml just buy another new tank? come on that's less than a small can of coke.

Is the residual that much of an issue?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[CanosSSCS]

CDA: clean dry air

residual fluid has been an issue during shipping, when the system might be exposed to "extreme" temperatures. Tanks are custom and can't be picked off a shelf.

 

[LittleInch]

Stick a bag of desiccant crystals in it?

You either flush it with some sort of hygroscopic liquid which hopefully then evaporates better than water (methanol works really well but is a bit nasty and can explode or catch fire) or you blow super dry warm / hot air through the thing until it doesn't have any fluid left. This can take quite a long time.

Or pull a high level (20mbara) vacuum to the extent that the water boils and escapes through the vacuum pump. This can also take quite a long time.

Or stick it in an oven at > 100C for about 15 minutes.

How long have you been doing the cold dry (how dry?) air for?

How long have you got to get the water out?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MikeHalloran]

I was peripherally involved with a bio-measurement system that used 'dry plumbing', where aqueous liquid was introduced at the start of a cycle and drained at the end.
It worked great, for customers who kept it cycling 24/7/365.
For customers who used it occasionally, it basically needed an overhaul after a couple hours of idle time.

I was also involved in generally similar units that were never drained or seriously flushed, and they gave less trouble from idle time,
and tended to run more consistently once the interior was coated with some sort of naturally occurring bio-film,
which appeared despite nasty anti-bio additives in the reagents.

I was also peripherally involved with units that were internally flushed with ethanol after every cycle.
They were reported to be pretty decent units, except for the flammable waste ethanol flow, which became a regulatory concern in some locales.

We could possibly offer more help if we understood more about what your system is intended to do.
E.g., for some economic situations, discarding an entire 400ml system may be cheaper than cleaning it for reuse.









Mike Halloran
Corinth, NY, USA

 

[itsmoked]

Wrap it with a small flexible heater and heat it up as warm as circumstances allows.

Simultaneously blow only enough air thru it to turn over the air in it about twice a minute.

Keith Cress
kcress -

http://www.flaminsystems.com