Oxy/propane

[lexi]

I made something a few months back out of a Propane bottle and just screwed the top right off. Nothing there but fitting and valve. I thought Acetylene had wadding and acetone inside cylinder?
Alex

 

[Rail_Head]

I was under the impression that Acetylene cylinders were constructed in two halfs? Because acetylene is unstable at high pressures the only way to get sufficient quantities into a bottle is to dissolve the acetylene in acetone.

The two halfs are filled with an asbestos/cement mixture welded together and baked. After baking, the material forms a honycomb inside the tank. Liquid acetone is the put into the tank as it asorbs 25 times its own volume in acetylene gas.

is this something like? - its a long time since I last sat in a class room!

 

[morph]

Bang on description! Thats what i was(badly) decribing!Once the honeycomb is damaged the acetylene goes unstable and will eventually blow the cylinder like shrapnal! I've seen a fire service training DVD on it and its just like a bomb.

If you look at propane valve opposite the thread there is a red plug(calor gas) , under that there is a disk and lead pressure relief device. Its only small but stops the cylinder turning into 1000 pieces!

 

[weldequip]

Acetylene only becomes unstable above a pressure of 1.5bar, and that is probably well on the safe side within health & safety limits. Just as Oxygen can react violently in contact with oil or grease, safety limits are well within normal operating proceedure. That said, the boffins have done their sums & better always to operate within the guidelines!
weldequip

 

[lexi]

There was a Landmark in Glasgow many years ago. It was a portion of a building that was missing. It sat like that for years. A lorry with acy bottles turning the bend at speed lost a few bottles and they detonated taking half of the building away.

Alex