Over Filling

[UaVaj]

What are the long term / short terms effect(s) of overfilling (say 10% above spec)?

Tank in question is: Worthington Steel HP120 with original hydro of Sept 05.

I have my own compressor.

 

[halocline]

Do a search, you'll find a monstro thread about this very subject just a few weeks ago.

 

[fppf]

 

[UaVaj]

I am not into overfilling. If I need more gas, I will just buy the next larger cylinder. The HP120 are more than enough.

Reason for asking is I want hot filled it to ~3750 so when it cools down to room temperature. It is close to the rated 3442.

It is a matter of convenience more than anything.

 

[tgsmith]

If you've got your own compressor, then just do a nice slow fill. There's no reason to give it a hot fill unless your busy and just haven't got the time.

 

[UaVaj]

If you've got your own compressor, then just do a nice slow fill. There's no reason to give it a hot fill unless your busy and just haven't got the time.

Maybe I am not understanding the term - "hot fill."

Let me explain. The compressor fills the tanks directly. There is no storage bank. Even with a cold water bucket (2/3 of the tank is submersed). The temp of the tank will increase during refilling.

Once the tank cools down. Whatever pressure it was cut off at. Will be less. In order to get a 3442 psi when cooled. Cut off pressure need to be around 3700 psi.

 

[fppf]

You are not over filling a tank by hot filling it to 3800 and letting it cool to 3442.
A cylinder is rated at a pressure AND temperature. HP steels are rated at 3442 at 70 degrees. So if the cylinder is hot, its allowed to be at higher pressures. That's why burst disks are so much higher than operating pressures.

But to second the opinion. Fill it slow to like 3600, let it cool for a few hours and top it off.

 

[dannobee]

I am not into overfilling. If I need more gas, I will just buy the next larger cylinder. The HP120 are more than enough.

Reason for asking is I want hot filled it to ~3750 so when it cools down to room temperature. It is close to the rated 3442.

It is a matter of convenience more than anything.

Perfectly acceptable. "Legally," it should be 3442 psi at 70 degrees. "Overfilling" to account for the change in temperature is not overfilling. DOT 49 CFR 173.302 is the regulation governing it if you wish to look it up.

Put that same tank in a car that is 130 degrees and the gas will be about the same pressure (3784 psi) anyway.

If you're worried about the pressure, get another fill whip for the compressor and fill two tanks at the same time.

 

[Luis H]

I am not into overfilling. If I need more gas, I will just buy the next larger cylinder. The HP120 are more than enough.

Reason for asking is I want hot filled it to ~3750 so when it cools down to room temperature. It is close to the rated 3442.

It is a matter of convenience more than anything.

As mentioned above, that is not an overfill. That fill is perfectlly acceptable per CFR codes.

 

[WD8CDH]

Luis,
Do you remember which CFR code covers hot fills? I can't seem to find it but I seem to remember there were specific temperature limits.