ScubaKris:
:lol: :lol: Holy Crap! :lol: :lol: I'll have to remeber that. I've got a couple 72's from 1955 that just passed hydro again. Get looks from other shops and people when I go to get em filled.
Dry Fill?
- Thread starter MrBill_FTL
- Start date
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:lol: :lol: Holy Crap! :lol: :lol: I'll have to remeber that. I've got a couple 72's from 1955 that just passed hydro again. Get looks from other shops and people when I go to get em filled.
I don't understand the thing about being seen. If you are that concerned buy some neon yellow fins like I have. No problems getting seen. Unless I don't want to be. Then I wear all black. But with all black the gray of the tank stands out like a sore thumb anyway.MrBill_FTL:
cinder4320
Contributor
You asked about the price to fill the 100HP steel vs. an AL80. It should be the same. We dive with the exact tank you have and pay the same to fill our 80's and our HP steel 100's. Its just air after all and most of the cost is occured with equipment, training, etc. so putting a little more air in your tank doesn't cost them more. We fill all of our tanks with the same discount card (100 fills $200) regardless of size.
Miranda
Miranda
"Nemrod, I remember someone commenting on a quick informal study they did regarding a water bath.
IIRC, the conclusion was that the final tank psi was the same whether filling in a water bath or not when filling to the same psi.
Sure, the tank *feels* cooler when it comes out of the water bath, but apparently it doesn't actually change the internal *air* temperature any significant amount.
Did you ever do any direct comparisons such as this? What were your findings?"
No, I did not do a statistacal study, I did fill enough tanks to see that a circulating water bath of cool water helps prevent some of the heating, speeds up the cooling interval thus allowing an overall fill time to be reduced. People have studies that come to weired or non-conclusions all the time to support their belief system, so be it, water absorbs heat and lot's of it and physics is generally not altered by belief systems.
"I understand what you're saying about a production environment. I've only seen this type of demand in N. Florida,"
Or Friday afternoon before everybody wants their tanks or the Tuesday and Thursday afternoon before scuba class back in the day classes ran for weeks and had fifteen to thirty students (pre PadI saturation) and instructors dropped off piles of tanks. N
IIRC, the conclusion was that the final tank psi was the same whether filling in a water bath or not when filling to the same psi.
Sure, the tank *feels* cooler when it comes out of the water bath, but apparently it doesn't actually change the internal *air* temperature any significant amount.
Did you ever do any direct comparisons such as this? What were your findings?"
No, I did not do a statistacal study, I did fill enough tanks to see that a circulating water bath of cool water helps prevent some of the heating, speeds up the cooling interval thus allowing an overall fill time to be reduced. People have studies that come to weired or non-conclusions all the time to support their belief system, so be it, water absorbs heat and lot's of it and physics is generally not altered by belief systems.
"I understand what you're saying about a production environment. I've only seen this type of demand in N. Florida,"
Or Friday afternoon before everybody wants their tanks or the Tuesday and Thursday afternoon before scuba class back in the day classes ran for weeks and had fifteen to thirty students (pre PadI saturation) and instructors dropped off piles of tanks. N
We don't need statistics to gain a basic understanding of thermodynamics.
Water conducts heat faster than air. We get cold faster in water than in air and so do tanks. Similarly it will take more energy to heat an object in that water bath than it will in air because the heat is being conducted away faster. It's a pretty simple concept.
Water conducts heat faster than air. We get cold faster in water than in air and so do tanks. Similarly it will take more energy to heat an object in that water bath than it will in air because the heat is being conducted away faster. It's a pretty simple concept.
Correct... however, unless you are circulating water that is significantly cooler than than the tank being filled, you will not see any real advantage in a water bath. Lets be honest here, a large majority of the fill stations that have a water bath are just a tub that is filled with water at room temperature. With out that temperature differential and/or water circulation there is no conduction of heat out of the tank.MikeFerrara:
On wet fills - http://www.psicylinders.com/library/Current/wetfills.htm
The author is Bill High, The guy who wrote the book, standards, and procedures that visual inspectors use.
DM
The author is Bill High, The guy who wrote the book, standards, and procedures that visual inspectors use.
DM
fishb0y:
Our bath was not cooled or circulated (other than the water movement caused my putting tanks in and out) and there was still a huge difference. Even if the water is room temp it conducts heat away from the tank about 20 times faster than room temp air. That's not going to change until you heat the water tank and we never filled enough tanks in a short enough period of time to significanty heat the water bath. there was a lot of water in that tank.
If you fill slow enough that you don't significan't raise the temp of the outside of the tankt hen you won't see much of a difference unless the water bath is cooled but that's an awfull slow fill. Even a very slow fill will warm the outside of the tank if you're putting very much air in.
captain
Contributor
akscubainst:
Sounds like another rule/procedure written to address the lowest common denominator.
Translation, lets not educate people to do it correctly, lets just write something to meet the level of the dumbest rock in the pile.
Sideband
Guest
I would be really impressed if the shop even had the ability to fill a tank to 5000psi. Most shops can't even hit 4000psi.
Joe
Joe
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