Just out of curosity what is the reasoning against "flash filling"?

[MANN]

I would like someone to explain this to me. Please use math/science/physics/thermodynamics/fluid dynamics in your explanation, and not "because when it cools my tank only says 3500psi"

I already know that a fire/explosion requires 3 elements: heat (ignition), oxygen, & fuel. I know there is a fear that your tank will explode, but there should be no fuel in your tank. If there is you are already doing it wrong.

Does the sudden expansion hurt the aluminum interior/carbon fiber exterior of the tank? I can sorta see it hurting the alum, but the CF I would think would be strong enough to resist the sudden shock of the expansion.

Citing your source would be nice too.

[Sweet Tooth]

Whenever I go to a certain field that flash fills, my fill nipple o rings seems to blow out. I go to a different field that uses a HPA booster, this never happens with the booster. This happens quite frequently with the field that flash fills the tanks. Not just mine, but my friend's tanks, too.

[leloup]

What is flash filling? I assume just jerking down the fill control and filling the hpa tank? If so....oops.

[MANN]

Whenever I go to a certain field that flash fills, my fill nipple o rings seems to blow out. I go to a different field that uses a HPA booster, this never happens with the booster. This happens quite frequently with the field that flash fills the tanks. Not just mine, but my friend's tanks, too.

There are quite a few different designs of fill nipples. I know PE ones are horrible to do what you are talking about. Better ones have never given me problems.

Edit:
None the less that is no reason to not flash fill.

[MANN]

What is flash filling? I assume just jerking down the fill control and filling the hpa tank? If so....oops.

yep....dont worry your not alone.

[maniacmechanic]

Aren't you an Enginering student ?
This is all of the cuff , " flash filling " is putting a large amount of Air psi / volume through an orifice fast , generating heat , I don't know how much heat it takes to expand a closed container , if said container does expand and it is done over & over & over , I would think it would over time fatigue the container , no matter what it is made of , over time
All metals fatigue over time & work , I work on heavy equipment , I've seen large thick pieces of steel , that one would never think would break , ending up broke & twisted

[y0da900]

When flash filling, you are compressing the air so rapidly that there is a (intense sometimes) build up of heat. That heat, combined with the oxygen rich environment of compressed air, is 2/3 of the ingredients for a single stroke single cycle diesel engine (i.e. tank goes boom). If you have volatile vapors in your tank (caused by using inappropriate lubricants), then it could be very very bad. The less dangerous, but more annoying on a daily basis problem, is that as the tank comes back down to ambient temperature, the pressure drops as well. You can flash fill to 4,500 psi and be left with 3,500 psi in the tank after cooling (with no leaks).

[sjrtk]

Simple explanation I use is the high speed of the flash fill compresses the air in the tank quickly. Causing heat build up and a "false" pressure reading. Then when the tank, and relating compressed air cool to ambient temperature the pressure drops to an actual "accurate" reading. Filling the tank slower reduces the heat build up and the resulting pressure loss. But also as maniac stated it would be less shock load on the material of the tank. The latter possibly (I have no idea how much) reduce the service life of the tank. Best answer i have for you.

[Beemer]

Aren't you an Engineering student ?
This is all of the cuff , " flash filling " is putting a large amount of Air psi / volume through an orifice fast , generating heat , I don't know how much heat it takes to expand a closed container , if said container does expand and it is done over & over & over , I would think it would over time fatigue the container , no matter what it is made of , over time
All metals fatigue over time & work , I work on heavy equipment , I've seen large thick pieces of steel , that one would never think would break , ending up broke & twisted

^^^^^^THIS...................but here is some more for you.

http://www.nrgnair.com/MPT/02AIR/01air.htm

Ask anyone who has filled scuba tanks about the concern for big temperature change. Dangerous temperature change. Temperature change caused just by moving compressed air, at ambient temperature, from a big tank into a smaller tank at ambient temperature. If the procedure is performed too quickly, there is a very real danger that the smaller tank could explode like a bomb, putting life and limb in great jeopardy.

The question to ponder is, "Where does the energy come from to explode the scuba tank if the max air pressure in the storage tank does not exceed the scuba tank safety test pressure?"

Exploding compressed air tanks constitutes an argument against the "conventional" air car like the MDI which stops to fill its tanks about every 30 miles. Yes, filling can take place in a minute or less, but you would be prudent to be hiding around the corner.

The reason for this dangerous circumstance is based upon the characteristics of suddenly compressing air. Sudden compression of air generates an enormous amount of heat.

http://www.ukpsf.com/documents/hpa.pdf

Make sure that the source of air that you use to fill your bottle is set to deliver air slowly. Bottle fires
require heat to occur, the slower the bottle fills, the less likelihood there is for heat to be generated.regulator was thread locked on when you bought it, and for some reason you have removed the regulator from the bottle, maybe to fly to another country, the chances are that you have damaged the threads in the bottle and it could be useless. If this is the case, please contact the manufacturer of the bottle and ask them to give you the details for the person who can measure the threads for you to make sure they are still in tolerance.
NEVER be screwed in hand tight to the bottle. All regulators ; again these will be available from the manufacture.


More for you to read in these threads.

http://automags.org/forums/showthrea...ht=flash+fills

http://automags.org/forums/showthrea...ht=flash+fills

http://automags.org/forums/showthrea...ht=flash+fills

http://automags.org/forums/showthrea...ht=flash+fills




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[DeuceSV]

When I own my own venue I'm going to have flash-filling... but with strippers filling your tanks.

[sjrtk]

but with strippers filling your tanks.

Well that solves all my moral problems with it.

[leloup]

When I own my own venue I'm going to have flash-filling... but with strippers filling your tanks.

That is still not safe. What about the old men? Let's see - bombs or heart attacks...

[Beemer]

LOL you funny guys..........Keep it on topic. Dont make me remove your useless posts so you can hate on me for removing your useless posts.

This post could self distruct.

[DevilMan]

This post could self distruct.

If only the post'r would do the same...

oh and its dEstruct...

DM

[MANN]

Aren't you an Enginering student ?
This is all of the cuff , " flash filling " is putting a large amount of Air psi / volume through an orifice fast , generating heat , I don't know how much heat it takes to expand a closed container , if said container does expand and it is done over & over & over , I would think it would over time fatigue the container , no matter what it is made of , over time

haha. Yep at least for another year.

I understand 100% of why the heat occurs. I was just thinking what kind of impact it has on our bottles. Most of the info that I have read is geared toward flash filling scuba tanks. Carbon fiber wrapped tanks are not the same, and IMO should not be treated the same.

I wonder if anyone has actually calculated the heat transferred during a fill. I would think that the smallest diameter of the filling process is the fill nipple. So in theory we should be able to calculate the temperature inside the tank assuming an instantaneous fill (which would be worst case scenario because we cannot do so). I kinda doubt that it is that outrageous. I would guess @ 200F. That does not seem to me like that can cause catastrophic failure, and that if it did slightly damage your tank that it would be caught on the next hydro cycle.

I guess I am just not 100% convinced that flash filling is going to "blow up your tank". It seems that there are too many tanks that get flash filled repeatedly and then rehydro just fine.