Fills

[JamesK]

What are your thoughts on the proper way to fill? Some people preach that you should put the bottles in a water tank, some say no way! Others say it depends on the mix they are filling. I know that their are pros and cons to each, I would just like to know what you think.

I am trying to get an idea of what the general concensus of the board is. Ecspecially from those of you who do your own filling/blending.

Thanks.

[WYDT]

Originally posted by JamesK
What are your thoughts on the proper way to fill? Some people preach that you should put the bottles in a water tank, some say no way! Others say it depends on the mix they are filling. I know that their are pros and cons to each, I would just like to know what you think.

I am trying to get an idea of what the general concensus of the board is. Ecspecially from those of you who do your own filling/blending.


If you're doing straight fills (either air or premixed) I don't think it would matter one way or the other... if mixing, especially with Trimix it's a different story...

If you do your own you (usually) have the luxury of time and can do them very slowly so the heat issue is a moot point. Therefore most homebrewers I know don't use water. Not to mention water is messy in the garage. :) O2 should be filled very slowly in any event. Most shops that use water do it because of time constraints.

I've heard (but don't know it as fact) that it stresses the tanks more to use water but I think (if true) it's not very much and unless you plan to keep your tanks 200yrs it wouldn't make a difference.

DSAO!

[WreckWriter]

I vastly prefer water, not only for the cooling but also as a (small) safety factor just in case.

Sure, if you fill slowly enough you can get a decent fill dry, it's easier wet.

I don't have my own fill station but the one personal station that I'm familiar with (a complex trimix station with Haskell) uses a water tank. On the other hand, my LDS fills dry for all mixes.

Tom

[scuba_guy]

we fill at 600psi/min and for O2 we slow it done to 60psi/min we don't fill in water. with steel tanks we let them sit a few hours and then top them up again

[100days-a-year]

We fill 100psi/min+ - ,this is especially critical in 02(can you say abdiatic)no water and top-offs are when tanks are cool to touch.We fill 8-30 tanks a week air,nitrox,deco gasses and mix.Hot filling lp steels doesn't hurt but I'm in no hurry .Haskell & booster pump generate serious heat so slow is good.In my next life I'll get omar to design me a Rix continous blend station.gotta get a He tester 1st tho .PP is simple with just an o2 analyzer.

[DiveTub]

We fill all our tanks in water, in the long run it is better for the tanks as they are not subjected to so much heat.

Also I cant see a customer waiting round the store for an hour to get his steely topped off.

Cheers
Chris
PADI MSDT
http://homepage.mac.com/sydney_diver

[reefraff]

Filling Cylinders In Water- Time to Review (http://www.psicylinders.com/news.html)

Bill High runs P.S.I. and has presents pretty decent credentials as an authority on the subject. He has written a fairly comprehensive and balanced short piece about this subject - anyone with an interest should give it a read.

The wet-fill article is about halfway down the linked page...

Steven

[WYDT]

Originally posted by reefraff
Filling Cylinders In Water- Time to Review (http://www.psicylinders.com/news.html)

Bill High runs P.S.I. and has presents pretty decent credentials as an authority on the subject. He has written a fairly comprehensive and balanced short piece about this subject - anyone with an interest should give it a read.

The wet-fill article is about halfway down the linked page...

Steven

This article looks more like a "CYA" (cover your arse) to me. Many mentions of "the Law" etc.

Also I found this to be interesting... "A cylinder is full when an accurate gauge shows the marked service pressure at a temperature of 70 degrees F. "

So when will that cylinder be at 70 degrees in Florida in the summer time?? Not till it's been in the water at a N FL cave for several minutes! So if they don't want you to fill in water and they don't want you to overfill (to allow for cooling)... how are you going to get a full tank??

I'm neither for nor against wet fills as I really don't think it makes much difference (other than to speed up the process) but this article sure doesn't sway me away from wet fills. In fact it may do just the opposite....

Just my opinion... :eek:

[JamesK]

I have to agree with you there Rob. That article looks like they are simply trying to cover all their bases. I don't blame them at all for doing that either.

[WYDT]

Originally posted by JamesK
I have to agree with you there Rob. That article looks like they are simply trying to cover all their bases. I don't blame them at all for doing that either.

No, I don't blame them either. They have to keep their ducks in a row with regards to liability.

I'd really like to see an independent analysis but don't think it makes enough difference for someone to spend the time on it. I think most of the stuff you hear is just someone's opinion or conjecture that's been around so long it's become fact in some peoples minds. I've sure never seen any real evidence either way... other than when I need a fill and don't have an hour to wait for it... :D

[MikeFerrara]

Water getting in the tank is a valid concern. But...ever have your din valve/tank refilled after diving. Did the fill station slap the whip on and fill without blowing the valve threads dry. Water is in the tank. You often start the fill process with water in the valve threads.

Overfilling is a valid concern. They refered to a chilled bath. Where do you get one of those? Ours is room temperature. The bath helps keep the tank closer to room temperature, not below. Even very slow fills generate enough heat for the presure to drop enough to piss off customers unless you overfill to compensate. For my own fills I never woried about being 300 pounds under full, but everyone else sure pitches a *****. Before installing our bank system we filled streight from the compressor which only pumps about 4 cfm. This is a slow fill (20 minutes for an empty al 80. If filled to 3000 the tank would be warm to the touch and still cool to 2700 or so. A HP 100 would get hot and drop significantly in presure.

A room temp. water bath and a reasonable fill rate does a great job of letting you get a full tank WITHOUT having to overfill.