Safe Acetylene Flow Rate

[Mrwurm]

According to two books I have on gas welding, the maximum flow rate on any acetylene cylinder is 1/7 of the total volume per hour. I have a small acetylene tank (75 cu ft), so this formula tells me that I can safely use flow rates up to 10.7 cu ft per hour. This flow rate effectively limits me to Victor #4 tip running at the slowest end of its range. A #2 is actually the biggest size that I can use to its full capacity. /forums/images/graemlins/frown.gif

The books claim that exceeding this flow rate (10.7) will result in a dangerous overheating of the cylinder, possibly resulting in an explosion. /forums/images/graemlins/blush.gif

So, heres my point. I have coworkers that run their gas rigs (at home) at whatever flow rate they want and are not even aware of the rules. /forums/images/graemlins/shocked.gif Are they surviving on dumb luck, or are the guidelines exaggerated ?

 

[frank_f15]

i have use all kinds of burning and welding tanks, and have never given concideration to the max flow rate. not saying it is not possible but when is the last time u heard of an welding tank exploding because the user over extended the max flow rate? /forums/images/graemlins/confused.gif

 

[RJohnson]

There is a danger with undisolved acetylene having too high a pressure. Usually the pressure is around 5 to 8 psig line pressure. If you keep your pressure down you should be able to use any tip size your torch can handle.

 

[Mrwurm]

You're right Frank, I've never heard of one exploding. These books just have me a bit nervous because I don't have a lot of experience to back me up.

 

[Hollywood]

I think RJohnson has it right. This is from my textbook:

"Excessively high withdrawl rates will cause the acetylene to boil out the acetone. This rapid boiling can cause a portion of the acetone to be carried out of the cylinder with the acetylene. Withdrawing the acetone-acetylene mixture and burning it will contaminate the weld and may damage the rubber seals and internal parts of the regulator and other equipment. In addition to the danger caused by the damaged equipment, the cylinder itself may be damaged, resulting in another hazard."

So, there is the "by the book answer"! /forums/images/graemlins/cool.gif