Paintball

[idkfa]

Originally Posted by Chachi

I've got no idea why it failed, but a teammate of mine in college had a HP burst disk blow on his 68/4500 (yes, it was filled to proper specs). we just heard this really loud bang, and then his HPA tank froze over because of the venting. Hooray, PV=nRT! I've never seen that happen since.

Why would a HPA tank freeze over? I thought they get warmer as they vent, not colder.

[French t0ast]

Just send your tank to a friend down here through like USPS/dhl/fedex
Thats what I always do with my PB equipment.

[Chachi]

Originally Posted by idkfa

Why would a HPA tank freeze over? I thought they get warmer as the vent, not colder.

Ever fill an HPA tank and notice that it gets warm?

holding V and n constant (R is already a constant) in PV=nRT means that as pressure goes up, temperature must go up to make both sides of the formula equal each other.

do the same in reverse, just drop the pressure. temperature has to drop, too.

Normally you wouldn't notice a drop in temperature since it's so slight, but this was a full tank equalizing in a couple seconds.

[Jordan]

Originally Posted by idkfa

Why would a HPA tank freeze over? I thought they get warmer as the vent, not colder.

Pull a Schrader valve out of a tire's valve stem some day - you'll get frost on the tip of the valve. The air rushing through creates a venturi effect - low pressure area - which drop the temperature of the tip, and creates frost.

Or something like that.

Jordan

[aqua_scummm]

Originally Posted by Chachi

I've got no idea why it failed, but a teammate of mine in college had a HP burst disk blow on his 68/4500 (yes, it was filled to proper specs). we just heard this really loud bang, and then his HPA tank froze over because of the venting. Hooray, PV=nRT! I've never seen that happen since.

Did he leave it in the car or anything? Was it older?

As temperature changes, a full tank's burst disc flexes (due to the pressure change from temperature). Repeated flexing can weaken it to the point where the pressure it can hold is less than what it was originally rated to.

[Chachi]

Originally Posted by aqua_scummm

Did he leave it in the car or anything? Was it older?

As temperature changes, a full tank's burst disc flexes (due to the pressure change from temperature). Repeated flexing can weaken it to the point where the pressure it can hold is less than what it was originally rated to.

I wish I could give a good answer. on the morning in question it was a bit chilly outside (mid '40s, maybe), and it was within 10 minutes of filling his tank the first time that day (so maybe 9:30-10ish).

I do wish I knew more about what happened, though.

[idkfa]

Originally Posted by Chachi

Ever fill an HPA tank and notice that it gets warm?

holding V and n constant (R is already a constant) in PV=nRT means that as pressure goes up, temperature must go up to make both sides of the formula equal each other.

do the same in reverse, just drop the pressure. temperature has to drop, too.

Normally you wouldn't notice a drop in temperature since it's so slight, but this was a full tank equalizing in a couple seconds.

Thanks, I should have realized that given my past and current education.

[anomoly40]

I'm going to ship it to my friend, or maybe a local field. Still waiting on hearing back from Pure Energy.