Bottle and reg pressures

[vmaxnick]

I've got a question about bottles and regs which seems obvious at first glance but would warrant clarification; I recently bought a 5k 2nd hand bottle that had a 5k HP reg fitted. I wanted an LP reg on it, so I fitted a 4.5k crossfire reg, fine I thought, now it's a 4.5k system. It started me thinking though so I checked all my other bottles and found I had 3k regs on 4.5k bottles and even a 4.5k reg on a 3k bottle.
So common sense tells us that you must always go with the lower number. Is it acceptable to mix regs/bottles like this, what if someone filling a bottle makes a mistake and fills a 3k to 4.5k or 5k because of what it says on the reg (or fills a 5k bottle to 5k despite having only a 3k reg fitted?)
(I know you should always check the bottle and the reg but not everyone does)
I've just bought an Air America reg which someone has peeled the stickers off so you can't tell what pressure it's good for (The gauge reeds to 5k so I am going to treat it as a 3k reg to be sure)
What are the guidelines regarding mix/match of bottles and regs if any?)

 

[Skeet]

Not quite sure about a couple of the bits of your question...so excuse any stating of the obvious.

- Bottle storage pressure is nothing to do with output. So a 3k is not LP because it is less than a 4.5 or 5k.

- LP and HP refer only to the output pressure of a reg and are nominally, 450 and 800 psi respectively.

It is fine to have a 4.5k on a 5k bottle

It is very bad (BOOM) to have anything higher than a 3k reg on a 3k bottle.

Although test pressure of bottles are much higher than working pressure (see the HP burst disc 7500k on a 4.5k bottle) and the actual expected failure pressure of a healthy tank, is even higher still..putting a 4.5 or 5k reg on a 3k bottle, allows you to over fill the bottle, which will stress it and could lead to catastrophic failure.

 

[vmaxnick]

Not quite sure about a couple of the bits of your question...so excuse any stating of the obvious.

- Bottle storage pressure is nothing to do with output. So a 3k is not LP because it is less than a 4.5 or 5k.

- LP and HP refer only to the output pressure of a reg and are nominally, 450 and 800 psi respectively.


It is fine to have a 4.5k on a 5k bottle

It is very bad (BOOM) to have anything higher than a 3k reg on a 3k bottle.

Although test pressure of bottles are much higher than working pressure (see the HP burst disc 7500k on a 4.5k bottle) and the actual expected failure pressure of a healthy tank, is even higher still..putting a 4.5 or 5k reg on a 3k bottle, allows you to over fill the bottle, which will stress it and could lead to catastrophic failure.

Hmm

It is surely not good practice or safe (probably not even legal) to have a 4.5k bottle fitted with a 3k reg The 3000psi painted, stuck or engraved on the body of the reg is the SWP or safe working pressure. It has nothing to do with the output pressure which is high (800-850psi) or low (400-450) My question is; how, if at all is this mix and match checked. I had never thought to check my 2nd hand bottles to see if the SWP of the reg matched the SWP of the bottle and "Low and behold" some of them don't!
Whats really set me thinking is that I have just bought a 2nd hand 'Air America, The reg' someone has peeled all the stickers off and these regs came in 3k and 4.5k with no external differences.
It just worries me that these anomalies exist because there is one hell of a pressure difference between 3k and 5k. If a reg has been manufactured to withstand 3k + say 1k to test pressure and someone sticks it on a 5k bottle and fills it, it's going to blow! With possible catastrophic results.
Unless someone within the industry tells me that all regs are manufactured to withstand the highest pressures, I think I am going to try and get all my bottles and regs back to matched pairs!

Just an idea to maybe check your kitbags to make sure you don't have any bad mixes!

Just so we are all reading from the same script; I am talking about the engraving on the body of the reg, not the gauge, which is irrelevant!

The more I think about it, the more I think it is wrong to have any miss match, up or down could lead to fatal consequences. Is it just me that has noticed this?

I don't know, and that's the truth of it. I keep reading this thread and either way I look, it all seems wrong! If skeet is right then you can fit a 3k reg to a 5k bottle, presumably, as long as you never fill above 3k. But if the bottle says 4.5k or 5k, someone is going to be tempted to whack 5k in

 

[Tom Allen]

it is daft and dangerous to put a 3k reg on a 4.5k bottle. The main reason is it will get filled by someone to 4.5k.

5k is not available.

Unfortunately we are our own worst enemies when it comes to HIGH PRESSURE AIR, this is why i say

there should always be a trained person at the fill rig filling bottles.

You know it makes sense.

 

[vmaxnick]

it is daft and dangerous to put a 3k reg on a 4.5k bottle. The main reason is it will get filled by someone to 4.5k.

5k is not available.

Unfortunately we are our own worst enemies when it comes to HIGH PRESSURE AIR, this is why i say

there should always be a trained person at the fill rig filling bottles.

You know it makes sense.

Thank you Tom, I was about to Pm you the link to this thread as it is in danger of becoming dangerously misleading.
I think my answer is to match my regs and bottles ASAP
(Incidentally, I just bought a 1.5 L bottle 345bar SWP fitted with a reg marked 5000psi)
I take it, you mean 5k fills are not available?

 

[Tom Allen]

5000psi regs have been about for ages, but you try to get it filled to 5000 psi legally.

 

[vmaxnick]

5000psi regs have been about for ages, but you try to get it filled to 5000 psi legally.

So......Am I ok with the 4.5k reg on the 5k bottle?

 

[Tom Allen]

So......Am I ok with the 4.5k reg on the 5k bottle?

yes because there are no 5k fills. and if there was, the 500 psi extra would not make a great deal of difference.

 

[vmaxnick]

yes because there are no 5k fills. and if there was, the 500 psi extra would not make a great deal of difference.

Thanks.
I guess the smaller numbers (3k) are common sense really!
What sparked the confusion was two unfamiliar things coming along at once in the form of; the 5k bottle and reg and the Air America reg without markings.
Just got me thinking, then worrying!

 

[Tom Allen]

with the air america, if it's not marked i would fall on the safe side and assume it's 3000psi or even 3500psi.