Do you purge your regulators when you complete a useage?

[Copperdog]

My son is enrolled in the local Vo-Tech welding program. He has been instructed that any time he is finished for the day using the oxygen-acetylene or mig/tig welders to purge the lines of gas after closing the tank valves.
I have been accused of being a little conservative and it makes me sqeek when he does it. The pressure usually bleeds off overnight anyhow on its own.
I have never done this previously, and I have the same regulators I have had for many years. Is this something I should be doing, or is this a standard safety precaution that is followed in a school setting?

[Sonora Iron]

I too have heard of this from day one. It is a good practice, along with backing the adjustment valves off after each use.
But do I do it? No!

[davedarragh]

AWS Welding Safety

My son is enrolled in the local Vo-Tech welding program. He has been instructed that any time he is finished for the day using the oxygen-acetylene or mig/tig welders to purge the lines of gas after closing the tank valves.
I have been accused of being a little conservative and it makes me sqeek when he does it. The pressure usually bleeds off overnight anyhow on its own.
I have never done this previously, and I have the same regulators I have had for many years. Is this something I should be doing, or is this a standard safety precaution that is followed in a school setting?

Yes. It is stipulated by the AWS to shut off main tank valves, purge/bleed lines and loosen the regulator adjusting screws. This also prolongs diaphram life, and insures your pressure(s)/flow volume(s) are accurate when set.

[just_a_girl]

Remember, regulators are designed to regulate, not "store".

[Andy]

It also prevents a slow leak through the regulator from blowing the hose.

[Daniel]

Makes sense.

[Rick C]

[QUOTE=Copperdog;221699]
I have been accused of being a little conservative and it makes me sqeek when he does it. The pressure usually bleeds off overnight anyhow on its own.


Not to be a smart axx don't you do a leak test after you change tanks. If so there would not be any drain off over night. In reality when the valves are open or closed you are wasting gas if you don’t do a leak test. So if you not doing a leak test you are squeaking and not even knowing it. I know what you mean gas is high priced and don’t like to waste it.
I’m not bashing you like some do on here just bringing it to your attention leak test should be done for safety and waste purposes.
Good point you brought up helps make us think what we are doing right and wrong.
Rick C.

[walker]

You will not hurt the regulator leaving it pressurized! These are tough regs with hard seats. If regulators were prone to failure under a lockup condition we would all be dead by now due to the vast number of regulator stations by road sides and on gas meters around the world. I have worked on reg stations that sat for years at a time with several thousand pounds on them with no damage. Also, you will not blow a hose either, unless you have a damaged hose that will blow under normal operting condition, or unless you have removed the over pressure protection (pop off valve) from your reg. The bleed off seems to occur in older hoses as the gas permeates the hose. It is not a quick process, nor have I been able to detect it with soapy water.

[just_a_girl]

If you do not bleed the lines and the reg. has a rubber diaphragm, fuel gases can degrade the diaphragm material over time. Also, if there is a leak in the system it will cause the high pressure seat to continuously open and close to maintain the set pressure which may result in premature wear of the soft seat surface.

[nikodell]

I for one know of a welder that returned to his shop that was closed all night with a leaking co2 or argon gas tank which had displaced enough oxygen to render him unconscious and convulsing on the floor. He did survive but it could have easily gone another way. This was not because of just the lines being pressured, but tank valves and regulators open still.
I now tend to double check tanks and cringe when I hear of people storing tanks in a home or attached garage.

[Bodybagger]

As much as I am a believer in the right way versus the wrong way, I admit I never ever ever bleed my regulators off.

Why?

I figure that by the time you compress a cubic foot of gas at standard temperature and pressure into 2000psi on the high side and 30 psi on the low side of a regulator including all the hoses, you can just about cram that cubic foot in.

That means every 300 some odd purges, you've wasted an entire tank of gas.

If I did that at the end of every weekday to each of the 4 commonly used tanks of compressed gasses, I'd buy 5*50*4 /300 = 3.33 extra cylinders of gas each year.

And the only regulators I ever have replaced were due to mechanical damage (gravity usually involved). Call me a penny pincher, but that works out to a brand new Milwaukee porta band every year. There is not enough "feel good" in the equation to make me part with that money.

[MMW]

No I do not always purge them but I always shut off the bottles when done using them. I have heard you should always release pressure on the diaphram by backing off the adjusting screw but I don't do it unless the regulator is removed from the tank for storage.

[travlinbumm]

At our shop we just turn the bottles off. There will usually be someone using it with 10-12 hours, so no real need to bleed the lines.
At home I have to admit that I just turn the bottles off too.
I have a hard time wasting the gas….. maybe it doesn’t amount to much in the long run, but it still makes me cringe to let it go.

Here is a vid a friend sent to me, check out how this guy stores his gas bottles.
Oxygen, acetylene, argon all nice and cozy in the coat closet.

http://www.youtube.com/watch?v=fIpna...eature=channel

[Copperdog]

Thanks for the reply's.
It appears we are all over the map on this one.

[captkipp]

Bleed out?

I have both a mobile rig and a shop. The mobile unit has the reg and hoses removed before the truck moves from the job site. But the shop system stays hooked up all the time. Although we do shut the tank valves off. I'm not a fan either of violating safety. Nor am I a fan of wasting things. So bleeding off the system seems to me to waste a bit of product I could be using the next time.

I understand why the school would do it. To get the Kids into the "safety" habit. And I agree wholeheartedly with this. They'll get climatized to the "real" world soon enough! Not saying that it's right, just that's the way it is.