Can someone tell me what the Acetylene bottle pressure should be when it is full?

[Mart63]

I thought it was aerated absorbant clay type stuff. I know they have Acetone in them. "dissolved acetylene"

I never cut one open. I not got one now - swapped over to Propane and Oxygen years ago - for heating and cutting.

I liked gas welding - but with TIG sets and MIG welders it is sort not needed. Most brazing I do now is done by TIG - DC in pure argon.

Back in the 70s it was acetone and charcoal. Don't know if that has changed in the passing years.

 

[Robotstar5]

My local BOC branch used to have an acetylene cylinder outside the door that had split top to bottom and opened up. It had some kind of honeycomb structure inside it.

Did they use O/A to section it?

 

[Seadog]

Back in the 70s it was acetone and charcoal. Don't know if that has changed in the passing years.

I think they use/used Kieselguhr, a white clay.

 

[8ob]

So the solvent allows it to be 200psi in the bottle then?
How does the gas drawn off into the regulator at 200psi, not go bang, if it decomposes above 28psi?

Not much will burn/ignite without the presence of oxygen and with o/a that is at the welding/cutting tip.

Bob

 

[Bornfree]

Did they use O/A to section it?

View attachment 433246

No it had blown up. They put it there as a warning

 

[Kram]

Not much will burn/ignite without the presence of oxygen and with o/a that is at the welding/cutting tip.

Bob

Acetylene is one that can react without oxygen.

Its most singular hazard is associated with its intrinsic instability, especially when it is pressurized: under certain conditions acetylene can react in an exothermic addition-type reaction to form a number of products, typically benzene and/or vinylacetylene, possibly in addition to carbon and hydrogen.[citation needed] Consequently, acetylene, if initiated by intense heat or a shockwave, can decompose explosively if the absolute pressure of the gas exceeds about 200 kilopascals (29 psi). Most regulators and pressure gauges on equipment report gauge pressure, and the safe limit for acetylene therefore is 101 kPagage, or 15 psig.[54][55] It is therefore supplied and stored dissolved in acetone or dimethylformamide (DMF),[55][56][57] contained in a gas cylinder with a porous filling (Agamassan), which renders it safe to transport and use, given proper handling. Acetylene cylinders should be used in the upright position to avoid withdrawing acetone during use.

Copper catalyses the decomposition of acetylene, and as a result acetylene should not be transported in copper pipes.[62]

 

[Seadog]

Not much will burn/ignite without the presence of oxygen and with o/a that is at the welding/cutting tip.

Bob

Acetylene doesn't burn, per se. It breaks down into its constituent parts: carbon, hydrogen, and oxygen. But it does it very angrily

 

[Mart63]

And don't under any circumstances pass it through copper pipe.

 

[Seadog]

And don't under any circumstances pass it through copper pipe.

Copper nozzles?

 

[Jack Ryan]

can decompose explosively if the absolute pressure of the gas exceeds about 200 kilopascals (29 psi)

That is in air. Within the cylinder, and in the absence of air/oxygen, explosive decomposition can occur above 250 psi. That is why the cylinder pressure is limited to 250 psi.

One of the reasons you don't (shouldn't) "crack" an acetylene cylinder is that, if you are a bit slow, explosive decomposition of the expelled gas could occur.

Jack

 

[Jack Ryan]

Acetylene cylinders should be used in the upright position to avoid withdrawing acetone during use.

That is stated often but the consequences are not mentioned. Drawing acetone from the cylinder has two effects:

1. it can damage plastic and rubber affecting seals and regulator operation.
2. it reduces the volume of acetone in the cylinder increasing the amount of free acetylene and the chances of an explosive decomposition.

The same is true if the acetylene flow rate exceeds the "1/10th rule" for intermittent consumption or the "1/15th rule" for continuous consumption. Acetylene can only be drawn at the rate it comes our of solution so if a large flow is required, a large cylinder (or manifolded cylinders) are required.

The 1/10th rule used to be a 1/7th rule but has been updated.

Jack

 

[Erie Fred]

Interesting about Ruston Bucyrus......Apparantly a licensee of Bucyrus Erie.
Main plant was in Millwauki area, but had one in .....wait for it ....Erie.
Saw many cranes and shovels rolling out the big door as a kid here:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

maps.app.goo.gl

See the ramp in front right ? Crawlers of all kinds walked down it, onto Weshler avenue heading north.
That street was kept as the only brick street for many years, to handle the loads.

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

maps.app.goo.gl

The lot that is now a tire store was the testing ground, I saw up to a dozen machines there all running and digging:

Google Maps

Find local businesses, view maps and get driving directions in Google Maps.

maps.app.goo.gl

 

[Seadog]

That is in air. Within the cylinder, and in the absence of air/oxygen, explosive decomposition can occur above 250 psi. That is why the cylinder pressure is limited to 250 psi.

I disagree. The pressure is limited by the volume of the cylinder and the ability of acetone to absorb acetylene.
Acetylene does not need oxygen to decompose. I notice in this extract that 25 times the volume is quoted for absorbtion.

"Acetylene will not explode under low pressure at normal temperatures. However, it becomes unstable and spontaneously combustible when compressed to a pressure over 15 psi. Beyond 29.4 psi, it becomes self explosive, and a slight shock may cause it to explode even in the absence of air or oxygen. Since acetylene is shock sensitive and explodes above 30 psi, cylinders of acetylene contain acetylene dissolved in acetone, which lowers the danger of storing acetylene under high pressure. Acetylene cylinders are not hollow. They are packed with porous rock or crushed firebrick that is saturated with acetone. Acetylene happens to dissolve readily into acetone, and the dissolved gas is no longer in contact with gaseous O2, which does not tend to dissolve in acetone, and therefore is not as prone to decomposition by O2. The porous rock helps by minimizing the free volume of the cylinder, cooling and controlling any thermal decomposition before it gets out of control. Each decomposition of acetylene gives off heat. Acetone is capable of absorbing acetylene to approximately 25 times its own volume. Incidently, placing acetylene cylinders on their sides can cause the acetone and binders to dislodge. The result may be the formation of an acetylene pocket that is subject to polymerization and the possibility that liquid acetone will be released into the regulator. If storing upright is not possible, it is recommended that the cylinder be placed upright and left to stand for one half hour before using, although I read somewhere else that it should be standing upright for a period of eight hours. Restoring to the upright position allows the acetone to settle to back to the bottom of the cylinder, which in turn would prevent liquid acetone from running through the regulator. Anyway, as far as your pressures and limits on tip sizes 3 and above, the Victor chart I have shows that for welding and multi flame heating nozzles using acetylene, the acetylene pressure range for a #3 and above tip is 3 psi minimum, and 6 psi maximum. The acetylene ranges on the chart go from 3 psi minimum to 15 psi maximum, for material thicknesses of up to 1/32" to 4". Incidently, the "cutting with acetylene" chart shows ranges of 3 psi to 15 psi."

 

[Erie Fred]

The main question is ....Did the OP have enough to finish the job ?

 

[Jack Ryan]

I disagree.

With what specifically?

The pressure is limited by the volume of the cylinder and the ability of acetone to absorb acetylene.

That depends on what you mean by "limited". You could keep pumping the gas in, but you may not survive.

Once the acetone is saturated, additional acetylene would remain in gas form so that is where you stop pumping.

Acetylene does not need oxygen to decompose.

Which is why I wrote "Within the cylinder, and in the absence of air/oxygen, explosive decomposition can occur above 250 psi.

Jack

 

[eddie49]

is that an RB22

No, this is a 22RB:

ruston bucyrus 22rb (dragline) | eBay

Ruston bucyrus 22rb been standing for about 10 years good working order up till then will need recomisioning collection only.

www.ebay.co.uk

Interesting about Ruston Bucyrus......Apparantly a licensee of Bucyrus Erie.
Main plant was in Millwauki area, but had one in .....wait for it ....Erie.
Saw many cranes and shovels rolling out the big door as a kid here

The UK side, Ruston Bucyrus, were a major employer in my home town of Lincoln. They started as an offshoot of the local engine manufacturer Ruston and Hornsby. In the 50's the cranes and draglines going for export were proudly paraded through the streets of the city on low-loaders, sometimes in huge crates.

 

[Seadog]

With what specifically?

The quote that posted with the comment.

 

[hotponyshoes]

I'd guess if you remove the regulator from an "empty" bottle and leave the valve open the acetone would evaporate quite quickly?
I'd also expect some of it to be coming out as the acetylene is being drawn off? (although maybe the top pressure from the gas prevents that?)

Do they weigh all the cylinders when they refill them and top up the acetone first?

Just wondering if the users that make sure the bottle is correctly shut-off are paying more on the refills to account for the users that leave them open!

Also wondering if there is a cheap source of acetone that I'm missing out on..

 

[Jack Ryan]

The quote that posted with the comment.

Google will help you out.

In air, the regulator limit is about 15 psi. If that were the case in the cylinder, without air/oxygen, we would all have been incinerated long ago as the pressure there is about 250 psi.

Jack

 

[not done it yet]

Acetylene doesn't burn, per se. It breaks down into its constituent parts: carbon, hydrogen, and oxygen. But it does it very angrily

Nope. Acetylene is a hydrocarbon. No oxygen. It is C2H2. As carbon has a valency of 4, the two carbon atoms are connected by a triple bond. Its classification is an alkyne.

Alkanes have single bonds between the carbon atoms, alkenes exhibit double bonds between the carbon atoms and alkynes have the triple bond.