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

[hunter100]

The HP burst disk yes... but what about the LP one? What about the 3K reg with 4500 on top of it?

DM

The low pressure disk is 1800 psi, but its after the tank regulator. No matter what the pressure in the tank is, it would only see ~800 psi depending on the output setting of the regulator. That disk should only fail if the regulator seat leaked and let more pressure into the gun. But everything on the high pressure side of the regulator should be designed to withstand 5000 psi so the burst disk is effective.

[DevilMan]

The low pressure disk is 1800 psi, but its after the tank regulator. No matter what the pressure in the tank is, it would only see ~800 psi depending on the output setting of the regulator. That disk should only fail if the regulator seat leaked and let more pressure into the gun. But everything on the high pressure side of the regulator should be designed to withstand 5000 psi so the burst disk is effective.

Yes I know this. Which is why I said what about the 3K reg that has 4500 sitting on it. The point was that 4500 got pumped into a 3K tank.

With that said, why is something designed to not blow off until 5K only allowed to have 3K put into it?

DM

[cockerpunk]

With that said, why is something designed to not blow off until 5K only allowed to have 3K put into it?

DM

factors of saftey.

[DevilMan]

factors of saftey.

Wouldn't the safety factors be better suited to 3500 in a 3K instead of 5K in a 3K when we know that the other "level" is 4500 anyway?

And YES I know the safety factor. The question wasn't one that I didn't know the answer to. It was one that should be pondered by others. But thanx for the answer.

DM

[cockerpunk]

Wouldn't the safety factors be better suited to 3500 in a 3K instead of 5K in a 3K when we know that the other "level" is 4500 anyway?

And YES I know the safety factor. The question wasn't one that I didn't know the answer to. It was one that should be pondered by others. But thanx for the answer.

DM

for these things its typically 5/3rds for a saftey factor. so a 3k tank is proof tested to 5k (thus why the burst disk is a 5k), and 4.5ks are tested up to 7.5k (and thats why a 7.5k disk is on them).

the whole tank, regulator, and everything is proof tested (much like a hydro test) when it is made. then the burst disk is installed to make sure that in the event it is over pressurized, the disk will fail (knowing that the tank has already proven itself at higher pressures).

pretty basic fail safe.

[DevilMan]

me thinks you are missin the point here... and I'll try and keep it civil...

The burst disk is there why? To allow a blow off in the event of overpressure. The tank is "tested" to 4500. The burst disk pops at what? 4500?

So when BOTH of the items are set to pop at the same pressure, would you please care to tell me how you determine which one is going to come apart first?

Now would you also like to figure out what makes it different when I can willingly put a 7500 burst disk on a 3K bottle. Because I KNOW that the bottle can handle 5K so why not treat it like a 4500 bottle? When the burst disk, the bottle, and the reg are all tested to 5K.

Do you get it yet?

DM

[DevilMan]

pretty basic fail safe.

Sure thing... if you want to believe that... nothing like hanging yourself from a building on a rope that's rated to hold 300lbs, but is safety tested at 500 and adding a load to your weight that puts it right at 500lbs.

Would you do it?

DM

[cockerpunk]

me thinks you are missin the point here... and I'll try and keep it civil...

The burst disk is there why? To allow a blow off in the event of overpressure. The tank is "tested" to 4500. The burst disk pops at what? 4500?

So when BOTH of the items are set to pop at the same pressure, would you please care to tell me how you determine which one is going to come apart first?

Now would you also like to figure out what makes it different when I can willingly put a 7500 burst disk on a 3K bottle. Because I KNOW that the bottle can handle 5K so why not treat it like a 4500 bottle? When the burst disk, the bottle, and the reg are all tested to 5K.

Do you get it yet?

DM

the inital test proof testing is not a test to failure (that wouldn't make much sense). so the tank is known to be more then strong enough to hold up at above 5k. while the burst disk is known to fail below or at 5k. this way the burst disk will always be the first thing to fail, and when it does, it will fail in a safe way.

treating a 3k tank like a 4.5k tank would eliminate the factor of saftey. thus it would be an unsafe tank that could fail due to weakening by fatuge, damage, or material flaws.

a one time proof test (followed by later proof tests at a given interval) does not mean the tank's working pressure is at that level. it simply means it can, in the event that overpressure does happen, fail in safe manner. that is the purpose of the burst disk, and the factor of safety.

[DevilMan]

the inital test proof testing is not a test to failure (that wouldn't make much sense). so the tank is known to be more then strong enough to hold up at above 5k.

WRONG! It's not tested to hold up ABOVE 5K. It's tested TO 5K. And it's tested with water pressure in a water bath in a vertical position. All of which are different than what the use of the bottle sees. The water provides cooling, the water jacket provides a bit of resistance/pressure to hold it together and the vertical orientation provides NO lateral stress on the bottle. ALL are totally different that what the actual use of the bottle goes through.

DM

[cockerpunk]

WRONG! It's not tested to hold up ABOVE 5K. It's tested TO 5K. And it's tested with water pressure in a water bath in a vertical position. All of which are different than what the use of the bottle sees. The water provides cooling, the water jacket provides a bit of resistance/pressure to hold it together and the vertical orientation provides NO lateral stress on the bottle. ALL are totally different that what the actual use of the bottle goes through.

DM

simple logic my friend.

the only way to know how much pressure a vessel can hold is by testing it to failure. then you can point to the graph and say, wow that cyclender could hold 7.9 ksi! of course that knoweldge is pretty worthless now that the cyclender will no longer function. so you need to not test it to failure. when you do not test to failure, the bounds of the knowledge you gain is that the vessel can hold something above whatever your proof test was at.

think of it this way -

how strong is a rubber band? the only way to find out is to put in on a spring scale, and pull it until it breaks. or, if you had a given task that required it to support 5 pounts, you could proof test it to 12 pounds at the begining of life to insure that it can peform its given task. that rubber band can support at least 12 pounds, so it is capable of performing a task that requires it only supporting 6 pounds.

[DevilMan]

And thank you for proving my point... If it's tested to failure then you know where it breaks.

If you don't you only know it did NOT break up to that point.

Will the burst disk pop at EXACTLY 5K??? What if it's got a 10% variable? Then you have to worry that it could break at 4950, or maybe not break above just above 5K. What if the bottle breaks at 5100??? the burst disk had the 10% window which allowed it to 5500... but the bottle breaks at 5100. Hmmmm...

You jump out of an airplane with a parachute that can handle up to 350lbs. It's been tested to 350lbs and has a 10% window of variance. Would you jump out of that plane with the parachute and have a total load of 375lbs?

DM

[cockerpunk]

And thank you for proving my point... If it's tested to failure then you know where it breaks.

If you don't you only know it did NOT break up to that point.

Will the burst disk pop at EXACTLY 5K??? What if it's got a 10% variable? Then you have to worry that it could break at 4950, or maybe not break above just above 5K. What if the bottle breaks at 5100??? the burst disk had the 10% window which allowed it to 5500... but the bottle breaks at 5100. Hmmmm...

You jump out of an airplane with a parachute that can handle up to 350lbs. It's been tested to 350lbs and has a 10% window of variance. Would you jump out of that plane with the parachute and have a total load of 375lbs?

DM

each pressure vessel is tested to that proof test limit, so there wouldn't ever be a parachute that would hold less then 350 lbs. it would always hold at least 350 lbs if you proof tested each one to 350 lbs.

what point are you trying to make? the saftey features and design of pressure vessels is a pretty established area of engineering, what is your intention? from what i can tell, you have no point or purpose to your posts.

[DevilMan]

each pressure vessel is tested to that proof test limit, so there wouldn't ever be a parachute that would hold less then 350 lbs. it would always hold at least 350 lbs if you proof tested each one to 350 lbs.

what point are you trying to make? the saftey features and design of pressure vessels is a pretty established area of engineering, what is your intention? from what i can tell, you have no point or purpose to your posts.

That's because you are daft.

DM

[hunter100]

I think the most relevant question to this discussion is what is the reliability of the burst disk? If the tank is tested to 5000 psi without failure, but the burst disk doesn't fail until 5100 psi, then it is worthless. I would hope that 99% of the disks fail below the 5000 psi threshold, since that is the testing pressure of the cylinder they are protecting.

[DevilMan]

I think the most relevant question to this discussion is what is the reliability of the burst disk? If the tank is tested to 5000 psi without failure, but the burst disk doesn't fail until 5100 psi, then it is worthless. I would hope that 99% of the disks fail below the 5000 psi threshold, since that is the testing pressure of the cylinder they are protecting.

SEE CP!!!! HE GETS IT!!!!!

DM