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

[nerobro]

Get a small transmitting thermometer and put it inside of the tank... put on reg and do your fills. Have it transmitting from the get go. Keep an external one as well and keep them sync'd and see what you come up with.

Because you know finding an itty bitty thermometer that can transmit and all as well as fit through a 3/4" hole as well as withstand 4500PSI atmospheric pressure is just as easy as going to Home Depot or Lowes or Radio Shack...

DM

PIC 12 series, thermistor, four resistors, and a couple n size batteries. .... and pray it can transmit out of the bottle.

More importantly, running any sort of thermocouple into the tank isn't that hard. You'd need to drill two holes in an existing reg, and epoxy the darned thing shut.

Fill nipples should have a "standard orifice" to restrict fill rates.

[MANN]

regardless of what the heat is tho an ice bath would fix any potential problem. A bag of ice is only a couple bucks. A field would not loose that much by providing a cooler filled with ice water to the players.

[BigEvil]

One of my Dynaflows always blows an on/off oring when it gets flash filled to quickly. I have also seen both a Flateline 4500 and Crossfire 4500 reg seat let go from the same thing. I gotta figure High Pressure + Fast + Heat = bad no matter what. Thats why I love places that let you fill your own tanks.

[nerobro]

regardless of what the heat is tho an ice bath would fix any potential problem. A bag of ice is only a couple bucks. A field would not loose that much by providing a cooler filled with ice water to the players.

With fiber wrapped tanks, I do not believe a bath is the solution. Epoxy and carbon are a blanket over the aluminum bottle. They do not transfer heat well. Beyond that, shocking the tank with ice water isn't going to help the condition of the epoxy or how well the bottle is bonded to the wrapping.

I am also thinking you're underestimating how much ice would be necessary to maintain a cold water bath.

[Spider-TW]

I am also thinking you're underestimating how much ice would be necessary to maintain a cold water bath.

We would be filling often taking a lot of what hasn't melted with us.

Like BigEvil said, doing your own fills is really nice for the fill rate. I don't like open tables that much though. Anyone that has read any part of this thread would not be one of them, but some people really have no respect for any part of HPA equipment. When you find a bulging and kinked hose at one station, you have to wonder what the next person over is using and what they are doing.

If everybody argued about fill rates and macro lines I would be satisfied. It's the people that don't ask that we have to watch out for.

[nerobro]

And those push button fill rigs have no way of limiting fill speed. :-(

[vf-xx]

I have yet to see any evidence that it is dangerous/bad to flash fill.

-So my tank only has 3900 psi. Who cares I shoot a viking I can still almost get a case.

-Its dangerous because some people put oil in their reg. That sounds like a personal problem. I bet they only do it once.

-The heat will hurt the epoxy? That kinda seems odd. I dont even think that the epoxy matters in carbon fiber. Its the fibers that provide the strength. Correct? ( I am not very knowledgeable w/ CF ) Even if not will the temperature really get that high to hurt the epoxy. Remember firefighters also use carbon fiber air tanks.

It kinda sounds like "you have to wait 30 min after you eat to swim".

Ok, I'll admit that I haven't read the whole thread, so if I'm repeating something, well, it could use repeating.

Next: I did take a graduate level composite material design course, as well as a design through failure analysis course. I haven't run the math, but here are my concerns:

Presurizing and de-pressurizing the tank puts it through a load/unload cycle. This can cause inherent flaws in your pressure vesel to grow. These flaws are microscopic and it may take thousands or millions of cycles for a failure to occur from this. However this only holds true while you're under a set load limit. Exceed this limit and the cycles to failure drops dramatically.

Flash filling may cause localized pressures within the tank to exceed the standard load limits. Yes the bottle is designed with a significant safety margin (hydro to 1.5 MAWP, probably designed to 2.0 or higher). But as stated before, once you exceed a certian load level, you start eating into the expected life of the structure.

The epoxy is CRITICAL in design of a composite material. If you're in ME or something similar I'm sure you've studied stress/strain limits and modulus of elasticity and the like. For homogenous materials (typically metals) these properties are uniform in every direction. For composite materials they are not. You have one set of limits for stress/strain in the direction along the fiber, and nearly NONE perpendicular to your fiber. That's where your epoxy comes in. Again, without knowing the exact physical properties of the epoxy used, I can't calculate the failure limits of the epoxy, but since most binders are thermo set, and not thermo plastic, it's reasonable to assume that a certian level of heat will degrade the epoxy. UV radiation can also degrade some epoxies.

Actually, now that I think about it, it all comes down to whether or not this is a brittle material or a ductile material. I would hazard a guess that a CF tank is a 'brittle' type material. This means that it can be very good at withstanding high loadings, but NOT good withstanding sudden impact forces. Flash filling is a sudden state change, a rapid application of heat AND pressure which may exceed the design limits of the tank over time. Where if you fill slowly, you give the tank a chance to stabilize.

[MANN]

Ok, I'll admit that I haven't read the whole thread, so if I'm repeating something, well, it could use repeating.

Next: I did take a graduate level composite material design course, as well as a design through failure analysis course. I haven't run the math, but here are my concerns:

No thanks. My 400 level CE&ME material science classes are enough to make me realize that I don't want to specialize in material science.

Presurizing and de-pressurizing the tank puts it through a load/unload cycle. This can cause inherent flaws in your pressure vesel to grow. These flaws are microscopic and it may take thousands or millions of cycles for a failure to occur from this. However this only holds true while you're under a set load limit. Exceed this limit and the cycles to failure drops dramatically.

I agree. That is probably why HPA tanks have a 15 yr life. Flash filling does not provide higher pressures just more heat. It will cause the stress strain curve to be modified, but the next cycle should not change the curve. Once the work (I know thats not the term Im looking for) is done putting the same stress/strain will not hurt anything (assuming that you haven't already passed the maximum point).

Flash filling may cause localized pressures within the tank to exceed the standard load limits. Yes the bottle is designed with a significant safety margin (hydro to 1.5 MAWP, probably designed to 2.0 or higher). But as stated before, once you exceed a certian load level, you start eating into the expected life of the structure.

Actually not at all. The regulator from the hpa system are usually set below 4500 so you should never put more than 4500psi in your tank.

The epoxy is CRITICAL in design of a composite material. If you're in ME or something similar I'm sure you've studied stress/strain limits and modulus of elasticity and the like. For homogenous materials (typically metals) these properties are uniform in every direction. For composite materials they are not. You have one set of limits for stress/strain in the direction along the fiber, and nearly NONE perpendicular to your fiber. That's where your epoxy comes in. Again, without knowing the exact physical properties of the epoxy used, I can't calculate the failure limits of the epoxy, but since most binders are thermo set, and not thermo plastic, it's reasonable to assume that a certian level of heat will degrade the epoxy. UV radiation can also degrade some epoxies.

I agree with you here. I am just not sure that heat is that high. After all firefighters use carbon fiber HPA tanks, and they are exposed to higher heats than we put on our tanks.

Actually, now that I think about it, it all comes down to whether or not this is a brittle material or a ductile material. I would hazard a guess that a CF tank is a 'brittle' type material. This means that it can be very good at withstanding high loadings, but NOT good withstanding sudden impact forces. Flash filling is a sudden state change, a rapid application of heat AND pressure which may exceed the design limits of the tank over time. Where if you fill slowly, you give the tank a chance to stabilize.

I agree, but it is impossible to instantaneously fill a tank. I am not sure what is the fastest that you can fill a tank from empty to full (on a 4500psi system), but I would think it would take at least 20 seconds. I am not sure if that is considered "sudden"

[MANN]

With fiber wrapped tanks, I do not believe a bath is the solution. Epoxy and carbon are a blanket over the aluminum bottle. They do not transfer heat well. Beyond that, shocking the tank with ice water isn't going to help the condition of the epoxy or how well the bottle is bonded to the wrapping.

I am also thinking you're underestimating how much ice would be necessary to maintain a cold water bath.

That I am unsure of. I would think that putting the tank in 32* water would be fine, but I have no proof of that. As for amount of ice required to maintain a cold bath. Even if it took 10 bags a day(which it wouldn't that would be better than waiting 10min per fill. I am gearing that more toward larger games. The local field here can pull 70 people. 70 people filling an hpa tank at 10min per fill would be horrible.

[nerobro]

i'm not sure where you're coming from. Remember, our tanks are insulated. So a cold bath isn't going to help matters much.

The fills that worry me are the ones where the tank gets to hot to touch. Figure a 0-5k fill in 10 seconds or less. 20 or 30 seconds is pretty stinking slow by tournament ball standards.

a 30 second fill would make a massive difference.

[athomas]

I agree, but it is impossible to instantaneously fill a tank. I am not sure what is the fastest that you can fill a tank from empty to full (on a 4500psi system), but I would think it would take at least 20 seconds. I am not sure if that is considered "sudden"

It is possible to fill a tank at a couple of fields around here in under 10 seconds easily, if required. I'm estimating around 5 seconds. I don't like to do it. It just scares me and the heat factor keeps the fill level down. I like the ability to slow the fill to around 20 seconds. I don't consider a flash fill to be in the 20 second range. It still generates a fair amount of heat though.

[DevilMan]

I REPEAT!!!! SOMEONE NEEDS TO DETERMINE WHAT THE DIFFERENCE IN REGULAR FILL AND FLASH/SLAM FILLING IS!!!!

I would guess that most here have not dealt with FLASH filling...

DM

[Beemer]

I REPEAT!!!! SOMEONE NEEDS TO DETERMINE WHAT THE DIFFERENCE IN REGULAR FILL AND FLASH/SLAM FILLING IS!!!!

I would guess that most here have not dealt with FLASH filling...

DM

Its the same thing. I already posted what it is. Just call it FAST FILL, faster then JimmyJohns.

Fast, Slam, Flash its all the same...............If your fill cools off to less then what the supply was it got filled TO FAST, Slam, Flashed filled.

You need more info. I would bet you could fill a 68/45 with a 4500psi supply in way less then ten minutes and have a full fill. Then again what ever that time is it will STILL be too Sloooooow.

They got it right at Shatner ball 3 and with close to a thousand players I never saw crazy lines for air. And it wasnt no 10 minutes for a fill.

You will need to test temps at different fill rates. Find the max fill rate with out going over temp to get a FULL fill. Thats the safe right way. But like I said paintBall likes being stupid.

[DevilMan]

No Beemer most places I go it takes about 30 seconds I would guess to fill a bottle from 100PSI to 4500PSI... it fills fast at first then slows down as it tops off. Not saying this is the air flow and I know it's because of the the pressure increase...

BUT down at CPP I think it was, you handed your bottle to a person, they went back a few feet and hooked it up to the system, hit a button, disconnected the tank and brought it back to you... the button push took all of 2-4 seconds.

That is what I consider a FLASH/SLAM/whatever fill.

Just trying to clarify to folks the difference. At least to me and some others that have seen it. Maybe this coming weekend some folks could go out and play and take a quick video of the process at various places.

Wouldn't that be easy enough to do?

DM

[Beemer]

^^^^Crazy, scary, stupid stuff eh?





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