More Acetylene Questions

By stewarzi Date 01-12-2005 05:14

Howdy, I went down to the local welding supply store to have them check out my Acetylene regulator to see if it might be defective. The guy took it and hooked it up to one of his cylinders and proceeded to open the cylinder valve wide open. The clock jumped right up showing the cylider as full. Further, he said that the cylinder valve should always be wide open when in use, as a partially opened valve is a risk for explosion.

I've read that one should never open and acetylene cylinder valve more than 3/4 of a turn. I talked to an old geezer down at the airport who has been welding with gas longer than I have been alive, and he said the same thing.

Who's right here?

By Sand Man (**)

Date 01-12-2005 05:58

Zac,
As I Have been told, the old style linde bottles that use a key, 3/4 turn kept the flow down to keep the acetone in the bottle.
With the new style linde valve it doesn't matter.
Bottles with regular hand valves should be opened all the way.

Hope this helps, Jeff

By Lawrence (*****)

Date 01-12-2005 12:43

Stew,

Having been in the business a few years I can say the advice you have been given is risky at best.

ANSI Z49.1 is the commonly accepted safety standard for welding, cutting and allied processes in the U.S. and it says that fuel gas bottles (acetelene, mapp,etc) should never be opened more than one full turn. This way they can be shut off quickly in case of emergency.

If the bottle has a key, keep the key attached when the regulators are charged for service. If the regulators do not respond after opening the bottle up to one full turn than something is wrong with the bottle or the regulator. Some fuel gas cylinder valves will give full flow at about 1/8 turn and some take up to about 3/4 turn, those are average, again, anything more than 1 turn and you ought to just have the vendor exchange cylinders.

I don't know of any new type of fuel gas valve that requires a full open position. Challenge your supply guy to SHOW you manufactures instructions that back his claim of a fully open fuel gas valve.

Edit:
ANSI/AWS Z49.1 1999.... 10.8.4.8 Valve partially open.
An acetylene cylinder valve shall not be opened more than approximately one and one half turns and preferably no more than three-fourths of a turn, unless othrwise specified by the manufacturer.

By backpurge (*)

Date 01-12-2005 16:26

I work for Linde in the UK and part of my job function is safe handling and use of oxy fuel cylinders training.
You should never, ever open the cylinder valve handwheel more than "one turn of the wrist" otherwise how are you going to stop the gas flow in the case of an emergency.
Half to three quarters of a turn will usually open the valve fully.

Cheers - Bob

By Pepe Loco Date 01-16-2005 02:30

I am glad I don't open mine more than 3/4. When the hose got cut and began to burn, took me 1-2 seconds to shut it off.