Low pressure limit in Acetylene tank?

[mhorowit]

how low do you let your acetylene tank get before getting a refill? -
Mike

[Rocky]

mhorowit wrote:
> how low do you let your acetylene tank get before getting a refill? -
> Mike
0 PSI

[[email protected]]

On Aug 13, 12:41 pm, Rocky > wrote:
> mhorowit wrote:
> > how low do you let your acetylene tank get before getting a refill? -
> > Mike
>
> 0 PSI

Oxyacetylene rigs should have anti-backflash check valves at
the torch end of the hoses so that oxygen can't go back up through the
acetylene hose and into an acetylene tank that's at zero psi. If those
valves aren't there the operator shouldn't let the tank pressure fall
so low that oxygen pressure could do that. Oxygen in an acetylene tank
is a bomb, of course. Acetylene is already unstable enough without
that.

Dan

[John[_17_]]

mhorowit wrote:
> how low do you let your acetylene tank get before getting a refill? -
> Mike

As long as you have check valves in the lines, to the point where there
is not enough pressure to sustain the 3-5 psi regulator setting at the
flow demand of the torch.

Acetylene is only unstable if in the gaseous state ABOVE 15 psi.

John

[dpilot]

On Aug 13, 8:53 pm, John > wrote:
> mhorowit wrote:
> > how low do you let your acetylene tank get before getting a refill? -
> > Mike
>
> As long as you have check valves in the lines, to the point where there
> is not enough pressure to sustain the 3-5 psi regulator setting at the
> flow demand of the torch.
>
> Acetylene is only unstable if in the gaseous state ABOVE 15 psi.
>
> John

Paul Mee, the lead welder for Aeronca (sp) says never weld with less
than 100 pounds
if you want a good weld.
He said you ain't got enough heat. with less than 100 pounds.
I suppose if you just wanted to heat up something to bend it or
whatever, any psi would be ok
JimV.

[Stealth Pilot[_2_]]

On Sun, 24 Aug 2008 21:01:04 -0700 (PDT), dpilot >
wrote:

>On Aug 13, 8:53 pm, John > wrote:
>> mhorowit wrote:
>> > how low do you let your acetylene tank get before getting a refill? -
>> > Mike
>>
>> As long as you have check valves in the lines, to the point where there
>> is not enough pressure to sustain the 3-5 psi regulator setting at the
>> flow demand of the torch.
>>
>> Acetylene is only unstable if in the gaseous state ABOVE 15 psi.
>>
>> John
>
>Paul Mee, the lead welder for Aeronca (sp) says never weld with less
>than 100 pounds
>if you want a good weld.
>He said you ain't got enough heat. with less than 100 pounds.
>I suppose if you just wanted to heat up something to bend it or
>whatever, any psi would be ok
>JimV.

what may cause the low pressure limitation is the way acetylene is
stored in the tanks. I am told that it is in solution with some
solvent - acetone I think - and that it is not just a gas as in the
case of oxygen or argon. more like a soda pop with gas disolved in the
fluid to make it stable/non explosive in the bottle.
take the pressure down too far and you may not be getting acetylene as
the gas.

ask your distributor for the details though. this was related to me
second hand.(the guy was getting stuck into me in a model engineers
meeting)

Stealth Pilot

(paul mee is in the USA isnt he? shouldnt that be $200 or did you mean
psi :-) )

[Anyolmouse]

"mhorowit" > wrote in message
...
| how low do you let your acetylene tank get before getting a refill? -
| Mike

My supplier charges extra if you let it get below 100lbs or so. They say
they have to pull a vacuum on the cylinder and then recharge it when it
is returned too low. (I own the cylinders)

--
Anyolmouse

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