Author Topic: Tank pressure  (Read 167 times)

jimborg

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Tank pressure
« on: April 15, 2019, 05:27:49 PM »
My buddy filled up my tank yesterday with his Yong Heng compressor to 4500psi but when he brought it to me today it read 4250psi, should he have filled it to 4500psi?


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rsterne

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Re: Tank pressure
« Reply #1 on: April 15, 2019, 06:10:17 PM »
If it is a 4500 psi tank, then yes, and he likely did.... It probably lost pressure after it cooled, tanks get warm when you fill them....

Bob
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caniborrowsomeammo

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Re: Tank pressure
« Reply #2 on: April 15, 2019, 07:43:39 PM »
Like Bob said, they lose pressure when they cool after filling.
Next time have your buddy fill to 4500 then let the tank set for an hour or two, then top off to 4500 again. You will be closer to 4500 psi then.
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Alan

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Re: Tank pressure
« Reply #3 on: April 16, 2019, 05:01:39 AM »
One more comment. Depending on where you live, sometimes it is important to just forget about the resulting PSI.

Here in Roswell, New Mexico, 100° is about as common as over-active sweat glands! I actually had my Marauder (3,000 psi max fill), blow a 3.5k safety disk, after heating up in the field.
  • Roswell, New Mexico
Alan

I have an Omega compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your portable tank as a courtesy.

Frank in Fairfield

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Re: Tank pressure
« Reply #4 on: April 16, 2019, 07:07:47 AM »
When I have the tanks filled at the dive shop they suggest leaving it for one hour.
They fill the tank to 4500 then put it away til I come back.
Then they top it off.
In one hour it will lose 300psi...
My Shoebox fills so slow, that is not a problem..
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Re: Tank pressure
« Reply #5 on: April 17, 2019, 12:49:01 PM »
EVERYWHERE I read on HPA tank filling...the recommendation is NOT TO FILL TO MAX PRESSURE.  Heating and cooling can increase or decrease tank pressure to beyond recommended pressures as Alan states...if a faulty burst disc doesn't do it's job you basically have a bomb in your lap. 

NOT something you want I guarantee...I've been "privy???" to gas bottle explosions and when that happens people/animals/buildings just disappear or become rubble with very little trace evidence for identification.

A few hundred pounds of air volume/pressure just isn't worth it.

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steveoh

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Re: Tank pressure
« Reply #6 on: April 17, 2019, 04:01:18 PM »
I have found that filling at night or early morning in the shade in cool temperatures gives me less fluctuation in initial fill pressure to pressure after the tank settles/cools down. Also, covering the bottle with a layer or two of a white towel helps.
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jimborg

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Re: Tank pressure
« Reply #7 on: April 17, 2019, 04:55:25 PM »
Wow, I am learning a lot about this issue thanks so much guys!
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rsterne

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Re: Tank pressure
« Reply #8 on: April 17, 2019, 05:38:25 PM »
If you fill a bottle to the working pressure, the small amount of expansion you get from even a 50 deg. change in temperature will NOT damage the tank, as they are designed with a huge safety margin to look after exactly that situation.... Burst discs are supposed to be rated at the TEST pressure of the tank (60% more than the working pressure), so would never fail in this situation anyways.... A 3000 psi tank is fitting with a 5K burst disc, and a 4500 psi tank with a 7.5K burst disc.... CO2 bottles, which are rated at 1800 psi, use a 3K burst disc.... Those are the ONLY burst discs I have even seen in airguns…. and the Marauder does NOT have a burst disc anywhere in the gun.... I have never heard of a 3.5K burst disc, so no idea where that would come from, or what use it would have....

Bob
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Alan

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Re: Tank pressure
« Reply #9 on: April 18, 2019, 05:10:29 AM »
Bob, the Marauder in question is bottled, and regulated at 2,200 psi (at the time). The burst disk was marked 3.5 psi (I have several more of them), so it shouldn't have failed, but it did. That same Marauder is now set at 1,800 psi, and the burst disk is a 3.0k.

I also believe that burst disks work harden. The aforementioned Marauder was degassed and refilled (by me) about 10 times. Considering who "built" the Marauder, anything is possible.
  • Roswell, New Mexico
Alan

I have an Omega compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your portable tank as a courtesy.

sixshootertexan

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Re: Tank pressure
« Reply #10 on: April 18, 2019, 05:53:36 AM »
Using my shoebox type compressor I fill to 4500 and it stays there.
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rsterne

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Re: Tank pressure
« Reply #11 on: April 18, 2019, 08:30:45 AM »
Alan, I have never seen a burst disc that is 3.5K, that's an oddball, for sure.... Yes, burst discs can fatigue, they can even fatigue when connected to a Shoebox compressor, which has a "pulsating" output, if you are filling from below the setpoint pressure (so the regulator is open)…. I presume your 3.5K burst disc was on the "output" side of the regulator, and it had a 5K on the inlet side?....

Bob
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Alan

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Re: Tank pressure
« Reply #12 on: April 18, 2019, 03:44:26 PM »
That is correct. The gun is now equipped with a 3.0.

I think I have 3 or 4 of the 3.5s I bough from Amazon.
  • Roswell, New Mexico
Alan

I have an Omega compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your portable tank as a courtesy.