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New to acetylene


#1
...I'd suggest also Loosening /screwing out the pressure
adjustment valve on the regulator... 

This is a dumb question, but doesn’t screwing out the pressure
adjustment valve close off something? I know it’s counter-intuitive
to close off something by screwing it out (“Left-loosey” doesn’t
work here). Also, if you keep on screwing it out, won’t it finally
fall out? How far out is far enough?

I should go check this on my own acetylene torch, but it’s outdoors
and the temperature has fallen to near zero (F.).

TIA,
Judy Bjorkman


#2
This is a dumb question, but doesn't screwing out the pressure
adjustment valve close off something? I know it's
counter-intuitive to close off something by screwing it out
("Left-loosey" doesn't work here). Also, if you keep on screwing it
out, won't it finally fall out? How far out is far enough? 

It loosens the spring pressure on the diaphragm in the regulator
that sets the delivery pressure. This does allow the orifice in the
regulator to be closed off. SO yes you could say it closes off
something.

Jim

James Binnion
James Binnion Metal Arts


#3

Hi Noel,

I saw that episode too, lol. They actually showed where the tank was
the weakest, too, and this was at the very center on the bottom of
the tank. They had to shoot it there several times before they could
puncture it. But if I am remembering rightly, they also showed a
bigger danger: tipping the tank over & breaking off the
valve/regulator assembly. They showed the pressure of the tank
actually shooting through the steel and then cement wall of the
testing area they were using.

When I was nursing this happened in the hospital where I worked with
an oxygen tank. They WILL penetrate walls from the pressure release
of the gasses inside them. The one that was tipped and broke at the
hospital actually went through 3 walls. The valve had gotten hit
very hard when the tank fell, and I actually heard the resulting
"explosions" as it sailed through 3 patient rooms before lodging in
the outer wall of the building. My biggest fears, besides of course
observing normal safety precautions, is that very thing happening!
So when they say to make sure your tanks are secure, DO IT PLEASE!

Regards,
Teresa


#4

Regarding screwing out the pressure adjustment on regulators, I was
taught that if it was left in an “on”, or tightened position, to set
the pressure that the diaphragm would eventually take a set and make
adjustment more difficult after some period of time.

I have made it a habit to unscrew both fuel and oxygen until I feel
some wiggle. It’s a simple step that very little time.

Mike DeBurgh, GJG
Alliance, OH


#5

[Sigh] There is a world of difference between Oxygen, Acetylene and
Propane tanks.

Each has their dangers that are specific to each as well as common
dangers…

Smear Oil on the regulator threads and seat of an oxygen tank and
BOOM do the same with Acetylene or propane and not the same effect.

Break the cylinder valve on a compressed gas cylinder (Your choice
of Oxygen, a scuba diving tank, or any other tank containing gas
stored at 2250 PSI or more and you have an instant rocket.

Propane and to a lesser extent Acetylene are under a lot less
pressure, on the other hand however that fogbank that forms between
the valve being opened and it finding a source of ignition will give
you a whole new perspective.

This is just a long way of saying you cannot extrapolate from a to b
and figure that if this happens with A then it will happen with B
too.

Has numerous people have said, go see a Professional at your local
welding supply company for help in learning how to set up and test
your equipment.

Kay


#6
When I was nursing this happened in the hospital where I worked
with an oxygen tank. They WILL penetrate walls from the pressure
release of the gasses inside them. The one that was tipped and
broke at the hospital actually went through 3 walls. 

3,000 psi makes a helluva bang. That’s 432,000 pounds per square
foot. A typical car is in the ballpark of 2,000 pounds. It’s like
fitting 216 of those cars on a single square foot of space.

Paul Anderson


#7
This is a dumb question, but doesn't screwing out the pressure
adjustment valve close off something? I know it's
counter-intuitive to close off something by screwing it out
("Left-loosey" doesn't work here). Also, if you keep on screwing it
out, won't it finally fall out? How far out is far enough? 

It will fall out, I’ve done that before:P You want to screw it out
until it’s no longer under tension. The way a regulator is built is
thus:

There’s a diaphragm. The position of that diaphragm controls the
flow of gas out of the regulator. On one side, is the gas. On the
other side is a spring. When you screw the knob on the regulator in,
it pushes harder on the spring. That then pushes the diaphragm to one
side, causing the valve that’s attached to it to open further. The
output of that valve pushes back from the other side of the
diaphragm. When the pressure of the gas is enough to equal the
pressure applied by the spring, the valve closes. When you open the
torch valve, it lets gas out from the diaphragm. This causes the
diaphragm to be pushed off center again by the spring, opening the
valve to compensate.

In the end, you end up with it balancing the forces on either side
of the diaphragm. Increasing the force on the spring, increases the
force applied by the gas, and the force applied by the gas is it’s
pressure. So when you remove the tension from the spring, any amount
of gas on the other side forces the diaphragm to the other side and
closes the valve.

Paul Anderson


#8
Regarding screwing out the pressure adjustment on regulators, I
was taught that if it was left in an "on", or tightened position,
to set the pressure that the diaphragm would eventually take a set
and make adjustment more difficult after some period of time. 

An issue issue with leaving the adjustment knob screwed in on high
pressure regulators like those used on cylinders of oxygen is that
there is the possibility of damaging the tiny orifice of the valve
that acts to regulate the pressure by the sudden high velocity flow
of gas and particulate matter when the cylinder valve is opened and
the regulator valve is in the open position. This results in the
valve not being able to seal and then it can no longer regulate
pressure.

James Binnion
James Binnion Metal Arts


#9

And NO, it won’t come out. It stops when you unscrew it all the way.
You just keep unscrewing until it won’t go any more. Then the
acetylene is shut off.

John
Indiana


#10

A good series of guides for handling compressed and liquefied gases
and equipment is provided by air Products And Chemicals. These have
been in use a very long time and are revised when an occasion
demands:

http://tinyurl.com/ylqwwyx

jesse


#11

Just a comment about safety in general that this seems a good place
to put. Very often there are threads on Orchid that boggle the mind -
this one has had a bit of that, some are much worse. There is a
short list of essential life lessons, or a least things that make
life tolerable. One very important one is:

If frogs had wings, they wouldn’t flop their asses when they landed.

If your shop fills up with gas, it can explode

If you shoot a tank with an armor piercing bullet, bad things will
happen

If you don’t lie awake nights fretting over everything in your shop,
your family will die

If you drink acid, that would be a life-changing experience

On and on and on… If you didn’t win the lottery, it’s because
you were abducted by aliens the night before and they altered your
ticket.

Of course, we just treat each other with respect, act like normal
people, and leave the paranoid speculation at the door, most of us.
Don’t fill your shop with gas, don’t drink acid, don’t bathe in
methanol - that’s your job as a jewelry shop manager, large or small.
And use your head or bad things WILL happen - that means: GET
TRAINING. If you don’t understand acid, find out. If you are new to
torches, get trained or at least read some books, as it’s out there.
But, “If you’re driving along and a tank er truck full of cyanide
crashes in front of you, you can guess the rest.” will just drive you
nuts, not to mention the people around you. Almost all of the time,
it doesn’t.

There’s nothing in a typical jewelry shop run by 90% of Orchidians
that is especially harmful - again, with reasonable training.
Probably the worst hazards are machines and sharp tools. Even in more
industrial shops the re’s not so much - nothing like a chemical
factory has, that’s for sure… Life is too short to make up “could
be” hazards - there’s enough already.


#12

My 3 step procedure which is on an index card next to my tank so I
don’t forget:

  1. Turn tank key off.
  2. Light torch and bleed the line.
  3. Screw out regulator releasing pressure.
  4. Turn torch handle off.

I do this without fail each night I leave the shop. Can bad things
happen? Yes- I had a torch fire in the shop the first year I had my
shop. 2 fire departments and an ambulance. Dangerous and
embarrassing. I am not paranoid but I am thoughtfully conscious now
of using correct procedures.

Jean Menden
www.jmendensilver.com


#13
And NO, it won't come out. It stops when you unscrew it all the
way. You just keep unscrewing until it won't go any more. Then the
acetylene is shut off. 

I think this depends very much on the regulator, on my Victor
regulators it very much will come out, and I have had it come out.

Paul Anderson


#14

Jean - good idea to have your procedure written out so you don’t
forget. But I’d really like to know why you light the torch while
bleeding the line. I simply turn my tank off, then bleed the line
and turn the torch handle off, and then screw out the regulator
valve. Very early on I used to let the torch burn up the remaining
gas in the line and was told that this could cause problems because
the flame likely would go down into the line as it burned the
remaining gas. I was told to just bleed the line with no flame. So
that’s what I do. And there’s usually just a tiny bit of gas left in
the line anyway.

If I’m wrong, I hope someone tells me.

Kay


#15
good idea to have your procedure written out so you don't forget.
But I'd really like to know why you light the torch while bleeding
the line." 

I read about this shut down procedure in what used to be the
Lapidary Journal. They had a torch issue a few years ago. I have
always thought it would guarantee nothing left in the line. I suppose
it wouldn’t have much if it weren’t bled.

Jean Menden
www.jmendensilver.com


#16

Jean, you said you had a torch fire in the shop the first year you
had your shop - if the reason was anything that might help someone
else, may I ask what caused it? (I know what you mean about
embarassing fire calls - I was a fire fighter for the Forest Service
in Espanola, NM - one day my supervisor says, “I wonder what THIS
button does?” and pushed it. Apparently, THAT button was the manual
fire alarm - every fire engine in town showed up to our office, to
help the RED-faced firefighter shut off the alarm. Nice, huh?)

Blessings,
Susan “Sam” Kaffine


#17
Very early on I used to let the torch burn up the remaining gas in
the line and was told that this could cause problems because the
flame likely would go down into the line as it burned the remaining
gas. I was told to just bleed the line with no flame. So that's
what I do. And there's usually just a tiny bit of gas left in the
line anyway. 

I don’t think it matters really. Your torch should have a flashback
arrestor on both the oxygen and the acetylene. This will prevent the
fire going where it shouldn’t.

Paul Anderson


#18
I don't think it matters really. Your torch should have a
flashback arrestor on both the oxygen and the acetylene. This will
prevent the fire going where it shouldn't. 

I have yet to see a jewelers torch with flashback arrestors on it,
on the regulators yes but not on the torch. So you can possibly burn
up your hoses if you burn off the gas bled out of the regulator
rather than just venting it.

James Binnion
James Binnion Metal Arts


#19
I have yet to see a jewelers torch with flashback arrestors on it,
on the regulators yes but not on the torch. So you can possibly
burn up your hoses if you burn off the gas bled out of the
regulator rather than just venting it. 

Thanks Jim - and believe it or not, but my flashback arrestor is on
my torch. I was told to put it there when I first took a class in
jewelry making and I got used to it, so that’s where it has stayed.
It’s heavy but one adjusts to those things.

But I still don’t burn my torch after I turn off the tank. I simply
bleed the torch (through an open window and with my fan blowing.)
There usually is not much gas in the line anyway.

But thanks for your input.

Kay


#20

After reading all the comments and frequent references to flashback
arrestors I tried to buy some when ordering my second smith mini
torch from my online welding supply company.

However they said that Smith does not recommend the flashback
arrestors for the mini torch since it reduces the flow of gas too
much. Is that in fact the case? I use propane and oxygen.

(So far I am just turning of the gas at the bottle and shutting the
torch valves. I have drained the lines a few times but have no good
way of venting that so it seems a bit unnecessary. But then I don’t
know a lot about this torch business.)

Regards,
John Dyer